uticaj sastava za[titnog gasa na intenzitet...

UTICAJ SASTAVA ZA[TITNOG GASA NA INTENZITET OKSIDACIONIH REAKCIJA PRI VISOKOENERGETSKOM

MAG POSTUPKU ZAVARIVANJA

Doc. Dr. Sead Pai, Univerzitet u Mostaru, Mainski fakultet Mostar

REZIME Promjena sastava zatitnog gasa, u smislu promjene njegovog oku intenzitetu odvijanja oksidacionih reakcija u rastopljenom mhemijskog sastava, mikrostrukture i nekih mehani~kih osobina mistaìvanje uticaja sastava zatitnog gasa tipa Ar/CO2 i Ar/O2 napri visokoenergetskom Twin Arc postupku zavarivanja kutnih spoklonjena analizi koncentracije kisika u metalu zavara i njegovom

Klju~ne rije~i: zatitni gas, oksidacioni potencijal, hemijs

AN INFLUENCE OF SHIELDING GINTENSITY OF OXYDATION REACT

GMA WELDING PRO

Sead Pai, PhD., Assistant Professor, Faculty of

SUMMARY The change of shielding gas composition, in terms o changchange of oxydation reactions intensity in molten metal. This composition, microstructure and mechanical characteristics. Tinfluence of the shielding gas composition, type Ar/CO

f

2 chemical compostion in high power Twin Arc welding of fresearch was paid to analyzing the oxygen concentrationdifferent oxides.

Key words: Shielding Gas, Oxidation Potetnial, Chemical

1. UVOD Zavarivanje MAG postupkom se danas uglavnom izvodi u zatiti gasnih mjeavina na bazi argona, koje u svom sastavu obavezno imaju odre|eni procenat oksidirajuih komponenti – CO2 ili O2, koje sniàvaju jonizacioni potencijal zatitnog gasa, poveavaju stabilnost luka i smanjuju prskanje. Sa druge strane, kisik je veoma reaktivan i u stanu je da oksidie rastop, prvenstveno èljezo, zbog njegovog velikog afiniteta prema kisiku. Da bi se ova nepoèljna pojava izbjegla, elektrodna ìca se obavezno legira dezoksidantima, naj~ee manganom i silicijem, koji imaju vei afinitet prema kisiku od èljeza. Oksidacija mangana i silicija u zavariva~koj kupki rezultuje produktima kao to su MnO, SiO2 i 2MnO x SiO2, koji u formi ljake isplivavaju na povrinu zavara.

1. IN

The Gaexecutebase ofhave th– CO2 potentiastability.On thecould oits hugeoccurredeoxidishave thoxidationpool resSiO2, wweld su

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IZVORNI NAU^NI RAD
sidacionog potencijala, dovodi do promjene etalu. Ovo za posljedicu ima promjenu
etala zavara. U ovom radu je predstavljeno promjenu hemijskog sastava metala zavara pojeva. Posebna pa`nja u istraìvanjima je vezivanju u pojedinim oksidima.

ki sastav, oksidacione reakcije

AS COMPOSITION TO IONS IN HIGH POWER CEDURE

Mechanical Engineering, Mostar
ORIGINAL SCIENTIFIC PAPER e o its oxyda ion potetntia , leads to the results in changing weld metal chemical his paper presents an investigation as to
f t l

and Ar/O2, on change of weld metal illet welds. The special attention in this in weld metal and its connecting in

Composition, Oxidation Reactions

TRODUCTION

s Metal Arc Welding procedure is usually d in the protection of gas mixtures, on the argon, which in their composition obligatory e certain percent of the oxidation component or O2. They are decreasing the ionisation l of the shielding gas and increasing the arc In addition, they are decreasing spatter loss. other hand, oxygen is very reactive and it xidize the molten metal, primanly iron, due to affinity to oxygen. To avoid this undesirable nce, the filler wire is obligatory alloyed with ers, usually manganese and silicon, which e bigger affinity to oxygen than the iron. The of manganese and silicon in the welding ults in products like MnO, SiO2 and 2MnO x hich in the form of slag come out to the rface.

Preostali mangan i silicij ostaju ili u ~vrstom rastvoru ili u vidu fino dispergovanih ~estica oksida zarobljenih unutar o~vrsnutog metala zavara. Mangan i silicij u ~vrstom rastvoru poveavaju tvrdou metala zavara, a fino dispergovane ~estice oksida predstavljaju kristalizacione centre, koji uti~u na kinetiku raspada austenita. Tako, promjena hemijskog sastava metala zavara moè da uzrokuje promjenu mikrostrukture i mehani~kih osobina [1,2,3]. Uticaj oksidacionog potencijala zatitnog gasa na promjenu hemijskog sastava metala zavara predmet je istraìvanja opisanih u ovome radu.

The rest of manganese and silicon stays in the weld metal either in the form of solid solution or finely dispersed oxide particles. Manganese and silicon in the solid solution increased the hardness of weld metal and finely dispersed oxide particle represent the centres of crystallisation, which influence on the kinetics of austenite decomposition. Therefore, the change of weld metal chemical composition can cause the change of the microstructure and the mechanical characteristics [1,2,3]. The influence of oxidation potential of shielding gas on the change of the weld metal chemical composition has been the main topic of research, which is presented in this paper.

2. POSTAVKA EKSPERIMENTA Uticaj sastava zatitnog gasa na promjenu hemijskog sastava metala zavara istraìvan je na eksperimentalnim uzorcima koji su zavareni u zatitnoj atmosferi sedam razli~itih gasnih mjeavina: pet Ar/CO2 mjeavina, sa koncentracijom od 8, 12, 18, 22 i 30 % CO2, te dvije gasne mjeavine tipa Ar/O2 sa koncentracijama od 12 i 14 % O2. Za izradu eksperimentalnih uzoraka odabrani su kutni spojevi, formirani iz plo~evina debljne 12 mm za horizontalnu plo~u i 10 mm za vertikalnu plo~u, od ugljeni~nog konstrukcionog ~elika klase St 45, prema DIN 1779. Na osnovu kvaliteta osnovnog materijala odabran je dodatni materijal: elektrodna ìca oznake SG 3, prema DIN 8559. Hemijski sastav osnovnog i dodatnog materijala dati su u tabeli 1.

2. PROPOSITION OF THE EXPERIMENT The influence of the shielding gas composition on the change of the weld metal chemical composition has been researched on experimental samples, which were welded in the shielding atmosphere of seven different gas mixtures. Out of those, five are Ar/CO2 gas mixtures, with concentration of 8, 12, 18, 22, and 30 % CO2, two are gas mixtures of Ar/O2 type with concentration of 12 and 14 % O2. The fillet welds have been chosen as the experimental samples. They were made from 12 mm thick plates for horizontal and 10 mm thick ones for vertical plate. The plates are made of low carbon construction steel St 45, as per DIN 1779. The filler material has been chosen on the basis of parent material: the wire SG 3, Ø 1,2 mm, pursuant to DIN 8559. The chemical composition of the parent and filler material is shown in table 1.

Tabela 1.- Hemijski sastav osnovnog i dodatnog materijala Table 1. Chemica composition o parent and filler material l f Hemijski sastav – Chemical composition

C [%] Mn [%] Si [%] P [%] S [%] O2 [ppm] Osnovni materijal: Parent material

St 45 0,12 0,60 0,18 0,013 0,016 129

C [%] Mn [%] Si [%] P [%] S [%] O2 [ppm] Dodatni materijal: Filler material

SG 3 - ∅ 1,2 mm 0,10 1,70 1,00 < 0,025 < 0,025 --

Zavarivanje eksperimentalnih uzoraka je izvreno primjenom visokoenergetskog MAG postupka zavarivanja sa dvije elektrodne ìce, po Twin Arc sistemu. Parametri zavarivanja, prikazani u tabeli 2, odabrani su na takav na~in da omogue stabilan proces zavarivanja sa svakom od navedenih gasnih mjeavina, pri velikim brzinama zavarivanja i sa visokim u~inkom topljenja dodatnog materijala od 16,5 kg/h.

Welding procedure of the experimental samples have been done by usage of high power Gas Metal Arc Welding process with two electrode wires – Twin Arc system. The welding parameters (shown in the table 2) were this chosen to enable a stable welding process with usage of all above mentioned gas mixtures, at high welding speed and high melting rate of filler material, 16,5 kg/h.

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Tabela 2.- Parametri zavarivanja eksperimentalnih uzoraka [4] Table 2. Chemical composition o parent and filler material f

Parametri zavarivanja – Welding parameters

Napon luka: Arc voltage

U = 32V Brzina zavarivanja: Welding speed

vZ = 160 cm/min

Struja glavne ìce: Master wire amperage Brzina dotura ìce: Feed wire speed

IM = 270 A vM = 13 m/min

Slobodni kraj el. ìce: Free end:

l = 30 mm

Struja druge ìce: Slave wire amperage Brzina dotura ìce: Feed wire speed

IS = 320 A vS = 18,2 m/min

Protok zatitnog gasa: Shielding gas flow

Q = 32 l/min

Sastav zatitnog gasa je bio jedina promjenjiva veli~ina tokom eksperimenta. Svi drugi parametri zavarivanja su zadràvani na konstantnim vrijednostima, kako bi se na jednozna~an na~in moglo utvrditi kako sastav zatinog gasa, kod visokoenergetskog Twin Arc zavarivanja, direktno uti~e na odvijanja oksidacionih reakcija u rastopljenom metalu zavara, odnosno promjenu hemijskog sastava.

The composition of shielding gas has been the only one variable dimension during experiment. All other welding parameters were kept on constant values. In this way it was possible to find how the composition of shielding gas, (by Twin Arc Welding procedure), directly influence on intensity of oxidation reactions in the molten metal, and change of the chemical composition.

3. HEMIJSKI SASTAV METALA ZAVARA U ZAVISNOSTI OD OKSIDACIONOG POTENCIJALA ZA[TITNOG GASA

U cilju decidnog konstatovanja promjena hemijskog sastava metala zavara u zavisnosti od sastava zatitnog gasa, izvreno je ispitivanja hemijskog sastava metala zavara svih uzoraka. Da bi rezultati istraìvanja bili pouzdani, vrena su ponavljanja, pa su tako sa svakom od navedenih gasnih mjeavina zavarena po tri uzorka. S obzirom da su kao osnovni i dodatni materijali koriteni ugljeni~ni konstrukcioni ~elik u kombinaciji sa odgovarajuom ìcom, ispitivan je sadràj osnovnih elemenata: ugljika, mangana i silicija. Drugi legirajui elementi nisu tretirani s obzirom da se nalaze samo u tragovima. Sa posebnom pa`njom je izvreno ispitivanje sadràja kisika u metalu zavara, kao i detaljna analiza distribucije kisika prisutnog u metalu zavara. Rezultati ispitivanja hemijskog sastava metala zavara prikazani su u tabeli 3.

3. THE WELD METAL CHEMICAL COMPOSITION IN DEPENDENCE OF THE SHIELDING GAS OXIDATION POTENTIAL

In the aim of finding the changes of the weld metal chemical composition in dependence of shielding gas composition, the chemical analysis of all the welded metal samples has been done. To ensure that the research results are reliable, analyses were repeated. Thus three samples were welded with each of gas mixture mentioned. Considering that low carbon steel in combination with corresponding wire was used for the both parent and filler material the contents of basic elements; carbon, manganese and silicon were examined. The other alloy elements were not treated because they are present only in the traces. Special attention was paid to the analyses of oxygen content in the weld metal and analyses of oxygen distribution, in the weld metal. The results of analyses of weld metal chemical composition are given in Table 3.

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Tabela 3.- Rezulta i analize hemijskog sastava metala zavara [4] t.Table 3 Results of analyses on weld metal chemical composition

Hemijski sastav metala zavara Welding metal chemical composition

Redni broj No.

Sastav gasne mjeavine

Shielding gas composition

C [%] Si [%] Mn [%] O2 [ppm] N2 [ppm]

1. Ar + 8%CO2 0,154 0,150 0,151

0,354 0,370 0,376

1,106 1,008 1,013

370,1 368,0 359,7

47,2 53,3 55,5

2. Ar + 12%CO2 0,132 0,126 0,124

0,339 0,315 0,316

1,131 1,125 1,124

341,2 352,7 349,6

43,3 50,1 45,8

3. Ar + 18%CO2 0,161 0,156 0,153

0,302 0,312 0,290

1,003 0,924 0,920

368,3 407,9 411,2

38,6 30,2 30,1

4. Ar + 22%CO2 0,093 0,102 0,094

0,286 0,279 0,288

1,045 0,998 1,092

439,3 420,8 431,3

36,7 48,1 43,9

5. Ar + 30%CO2 0,112 0,122 0,126

0,303 0,288 0,283

0,956 0,958 0,947

400,9 371,3 388,5

39,0 43,3 42,6

6. Ar + 12%O2 0,144 0,151 0,138

0,180 0,186 0,192

0,805 0,820 0,824

493,3 489,9 462,7

40,3 39,6 33,8

7. Ar + 14%O2 0,231 0,229 0,211

0,242 0,257 0,256

0,895 0,909 0,923

524,9 538,1 484,3

49,4 52,2 48,7

Poredei prezentovane podatke o sadràju ugljika, mangana i silicija u metalu zavara sa podacima o hemijskom sastavu osnovnog i dodatnog materijala, tabela 1, moè se konstatovati da se nivo ugljika u metalu zavara zadrào na pribli`no istom nivou kao za osnovni materijal, dok se vrijednosti za mangan i silicij nalaze u granicama izme|u sadràja ovih elementa u osnovnom i dodatnom materijalu: OM = 0,60 % Mn < M[ = 0,80 - 1,12 % Mn <

DM = 1,70 % Mn, OM = 0,18 % Si < M[ = 0,18 - 0,37 % Si <

DM = 1,0 % Si.

Comparing the presented facts on content of carbon, manganese and silicon in weld metal with data of chemical composition of parent and filler material, Table 1, it could be stated that the level of carbon in the weld metal remained on the same level like in the parent material. The value for the manganese and silicon are in the limit between content of those elements in the parent and filler material: PM = 0,60% Mn < WM = 0,80 – 1,12%Mn <

FM = 1,70%Mn PM = 0,18% Si < WM = 0,18 – 0,37% Si < FM

= 1,0% Si

Ovakvo ponaanje se moè smatrati potpuno o~ekivanim, kako s obzirom na neminovno mijeanje osnovnog i dodatnog materijala pri formiranju zavarenog spoja, tako i s obzirom na ulogu mangana i silicija kao glavnih dezoksidatora metala zavara. Konstatovane razlike u sadràju pojedinih elemenata u metalu zavara razli~itih uzoraka mogu se dovesti u vezu i sa promjenama u sastavu zatitnog gasa, odnosno sa promjenom njegovog oksidacionog potencijala. Na slici 1 dat je grafi~ki prikaz uticaja sastava zatitnog gasa, izraèn preko njegovog oksidacionog potencijala, na promjenu hemijskog sastava metala zavara [4,5].

This behaviour is fully expected as the mixture of the parent and filler material in forming welds is inevitable and concerning the role of the manganese and silicon as the main deoxidisers of the weld metal. The differences in the content of some elements in the weld metal of different samples can be put in the connection with changes in the shielding gas composition or its oxidation potential. The figure 1 provides the graphical presentation of the influence of shielding gas composition, which is expressed through its oxidation potential, on changing the weld metal chemical composition [4,5].

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2 4 6 8 10 12 140,0

0,4

0,8

1,2

1,6

2,0

oksidacioni potencijal zaštitnog gasa OP = O2 + 0,45 (CO2)0,92

sadr

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u %

0

100

200

300

400

500

Si

Mn

sadržaj O2 u m

etalu zavara u ppm

l ,

O2

f

Con

tent

of

Mn

and

Si i

n w

eld

met

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%

Content of O

2 in weld m

etal in ppm

Slika 1.- Uticaj sastava zatitnog gasa, izraènog preko oksidacionog potencija a na promjene hemijskog sastava metala zavara [4]

Figure 1. Influence o shielding gas, expressed by oxidation potential, on changes of weld metal chemical composition

Sa dijagrama se moè uo~iti da sa poveanjem koncentracije oksidirajuih komponenti u zatitnom gasu (CO2 ili O2), dakle sa poveanjem oksidacionog potencijala zatitnog gasa, dolazi do poveanja sadràja kisika u metalu zavara. Vea koncentracija kisika poveava intenzitet oksidacionih reakcija, pa kao posljedica toga dolazi do pada koncentracije ugljika, mangana i silicija. Ovakve promjene su o~ekivane i u potpunoj su saglasnosti sa teorijom.

From the diagram, it is visible that the increase in concentration of oxidation component in the shielding gas (CO2 or O2) i.e. increase in the shielding gas oxidation potential, leads increases to in the content of oxygen in the weld metal. The bigger concentration of the oxygen enlarges the intensity of the oxidation reactions. As the consequence of that the concentration of the carbon, manganese and silicon is decreasing. Those changes are expected and they are in the ful compliance with theory.

4. ANALIZA DISTRIBUCIJE KISIKA PO OKSIDIMA

Poveanjem sadràja oksidirajuih komponenti u zatitnom gasu poveava se sadràj kisika u metalu zavara. Kisik, u svakom slu~aju, predstavlja vrlo tetnu i nepoèljnu primjesu u ~eliku, koja smanjuje mehani~ke osobine i naruava homogenost. Da bi se smanjila koncentracija i izbjegli nepoèljni efekti kisika, koji u metal zavara pri MAG zavarivanju dospjeva iz zatitne atmosfere, elektrodna ìca se obavezno legira sa manganom i silicijem. Ovi elementi imaju veliki afinitet prema kisiku, vezuju ga za sebe i u vidu ljake odstranjuju iz metala zavara. Ipak, odre|eni dio kisika ostaje u metalu zavara i to vezan u razli~itim oksidima. @eljezo sa kisikom gradi tri oksida: Fe2O3 (èljezo-oksid), Fe3O4 (èljezo oksidul - oksid) i FeO (èljezni oksidul). Prva dva oksida se ne rastvaraju u èljezu i u metalu zavara se mogu nalaziti samo kao uklju~ci. @eljezni oksidul FeO najvie moè da uti~e na osobine ~elika, a kao mikrokonstituent u strukturi ~elika nosi naziv vustit. Njegova ta~ka topljenja, u zavisnosti od sadràja kisika, se kree od 1370 do 1430 oC, a u strukturi se nalazi u obliku siunih globula.

4. THE ANALYSE OF THE OXYGEN DISTRIBUTION ON THE OXIDES

Increase of the content of oxidation components in the shielding gas leads to increase of the oxygen content in the weld metal. The oxygen, in any case, presents an undesirable constituent in the steel, which reduces mechanical characteristics and interrupts the homogeneity. To reduce the oxygen concentration and to avoid undesirable effects of the oxygen, which comes to weld metal from shielding atmosphere, electrode wire is obligatory alloyed with manganese and silicon. Those elements have the bigger affinity toward oxygen, connect it to themselves and remove the oxygen from the weld metal in the form of slag. In spite of that, certain part of the oxygen remains in the weld metal connected in different oxides. The iron and oxygen make three types of oxides: Fe2O3 (iron-oxide), Fe3O4 (iron oxidul -oxide) and FeO (iron-oxidul). The first two oxides are not dissolved in the iron and they can be in the weld metal only like includes. The iron oxidul, FeO, can substantially influence the characteristics of the steel. Like microconstituent in the structure of the steel, it is known under the term vustit. Its melting point varies between 1370 and 1430 OC, depending on the oxygen content, and in the structure it is found in the form of small globules.

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Smanjenje prisustva nepoèljnog FeO u strukturi metala zavara se postiè dezoksidacijom sa manganom ili silicijem. Procesi redukcije se odvijaju prema sljedeim reakcijama:

Reduction inpresence of undesirable FeO in structure of the weld metal is achieved by deoxydation with manganese and silicon. The reduction processes are developed as per the following reactions:

Mn + FeO → Fe + MnO Si + 2FeO → 2Fe + SiO2.

Nastali MnO se odstranjuje u vidu ljake, a zaostali dio mangan-oksida u strukturi metala zavara je znatno manje tetan od FeO. Udio mangana koji ne u~estvuje u oksidacionim reakcijama se rastvara u feritu, to izaziva poveanje svojstava ~vrstoe. Silicijum-dioksid SiO2 se, tako|e, u najveoj mjeri odstranjuje u vidu ljake, a zaostali udio se u strukturi metala zavara naj~ee ne javlja samostalno, kao silicijum-dioksid, ve u obliku razli~itih sloènih silikatnih uklju~aka: (FeO)2 x SiO2; (MnO)2 x SiO2; MnO x SiO2; MnO x FeO x SiO2, koji su po pravilu vrlo tvrdi i krti. Udio sadràja silicija koji ne u~estvuje u reakcijama oksidacije rastvara se u feritu gradei ~vrsti rastvor - siliko ferit, koji povoljno uti~e na elasti~na svojstva i poveava svojstva ~vrstoe [6,7,8]. S obzirom da prisustvo kisika, odnosno nekih njegovih oksida u metalu zavara, u zna~ajnoj mjeri moè da uti~e na promjenu mikrostrukture i kona~ne osobine spoja, to je pored standardnog odre|ivanja procentualnog u~ea kisika u metalu zavara, izvrena i detaljna analiza njegovog vezivanja u pojedinim oksidima (FeO, Fe2O3, Fe3O4, MnO, SiO2). Ispitivanje je izvreno prema standardu ISO 4491/3, a uzorci za ispitivanje sadràja kisika u metalu zavara su bili posebno pripremljeni valj~ii dimenzija ∅ 3 x 4 mm, izrezani iz sredinjeg dijela metala zavara. Analiza distribucije kisika po oksidima izvrena je na osnovu grafi~kog prikaza raspada pojedinih oksida prisutnih u svakom tretiranom uzorku, slika 2. Koli~ina kisika vezanog u odre|enom oksidu ekvivalentna je povrini ispod svakog od pikova predstavljenih na dijagramu (plava linija), a iz tabela uz dijagrame mogu se dobiti i podaci o procentualnom u~eu kisika vezanog za neki od prisutnih oksida. Sa druge strane, vrsta svakog pojedinog oksida, prisutnog u metalu zavara, se odre|uje na osnovu njegove temperature topljenja (crvena linija na dijagramu) i poznatih temperatura topljenja pojedinih vrsta oksida, tabela 4.

The formed MnO is mainly removed as slag, and the remaining manganese-oxide in the weld metal structure is less harmful than FeO. A share of manganese that does not participate in the oxidation reactions is dissolved in the ferrite, which provides enlargement of hardness. The silicon dioxide, SiO2, is in its biggest part removed as slag, whilst the remainder in the weld metal structure most often doesn’t come like silicon dioxide. But in the form of the different complex silicates: (FeO)2 x SiO2; (MnO)2 x SiO2; MnO x SiO2; MnO x FeO x SiO2, which are, by a rule, very hard and brittle. A part of the silicon, which does not participate in oxidation reactions, is dissolved in ferrite, making a solid solution - silicon ferrite, which favourably influence on the elastic properties and increase strength [6,7,8]. The presence of the oxygen or some of its oxides in weld metal can largely influence the change of microstructure and final characteristics of welded joints. Therefore, besides the standard analyses on oxygen percentage participation of oxygen in weld metal, a detailed analysis as to has been carried out its connections in certain oxides (FeO, Fe2O3, Fe3O4, MnO, SiO2). The analysis has been done pursuant to standard ISO 4491/3. The samples for the analysis on oxygen content in weld metal were specially prepared cylinders of dimension Ø 3 x 4 mm, cut from the middle part of the weld metal. Analysis on the oxygen distribution per oxides is made on the basis of graphics which represent decomposition of some oxides present in every treated sample, figure 2. The quantity of oxygen connected in certain oxide is equivalent to the surface under each of culminating point, represented on the diagram (blue line). Besides, it is possible to get data on percentage of oxygen tied in some of oxides present. On the other side, type of each oxide, present in the weld metal, is determined on the basis of his melting temperature (red line on the diagram) and well-known melting temperature of some oxide types, table 4.

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ID CODE: a-2 wt = 0,2502 g 09:26 15-Oct Oxygen = 0,03680 % Nitrogen = 0,00533 % Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area

1 2 3 4 5 6 7 8 9

0-19 sec 19-59 sec 59-99 sec 99-171 sec 171-182 sec 182-238 sec 238-252 sec 252-316 sec 316-395 sec

0,00000 % 0,00321 % 0,00165 % 0,00938 % 0,00083 % 0,00820 % 0,00099 % 0,00928 % 0,00325 %

Oxygen = 0,03680 %

ID CODE: a-4 wt = 0,2697 g 09:46 15-Oct. Oxygen = 0,03496 % Nitrogen = 0,00458 % Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area

1 2 3 4 5 6 7 8 9

0-20 sec 20-64 sec 64-97 sec 97-161 sec 161-180 sec 180-229 sec 229-245 sec 245-325 sec 325-395 sec

0,00004 % 0,00329 % 0,00131 % 0,00712 % 0,00147 % 0,00695 % 0,00110 % 0,00857 % 0,00511 %

Oxygen = 0,03496 %

ID CODE: a-6 wt = 0,2695 g 10:06 15-Oct. Oxygen = 0,04079 % Nitrogen = 0,00302 % Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area

1 2 3 4 5 6 7 8

0-21 sec 21-56 sec 56-110 sec 110-165 sec 165-166 sec 166-230 sec 230-310 sec 310-395 sec

0,00005 % 0,00211 % 0,00180 % 0,00822 % 0,00007 % 0,01375 % 0,01123 % 0,00355 %

Oxygen = 0,04079 %

ID CODE: a-8 wt = 0,2563 g 10:25 15-Oct. Oxygen = 0,04313 % Nitrogen = 0,00439 % Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area

1 2 3 4 5 6 7

0-16 sec 16-64 sec 64-139 sec 139-208 sec 208-272 sec 272-352 sec 352-395 sec

0,00000 % 0,00388 % 0,00865 % 0,01586 % 0,00673 % 0,00653 % 0,00148 %

Oxygen = 0,04313 %

Slika 2.- Distribucija kisika u metalu zavara za eksperimentalne uzo ke r

t fzavarene u zatiti Ar/CO2 gasnih mjeavina sa 8, 12 i 18 % CO2 [4]

Figure 2.: Oxygen distribution in the weld metal of experimental samples welded in the pro ection o Ar/CO2 gas mixtures with 8, 12 and 18 % CO2

- 214 -

ID CODE: a-11 wt = 0,2968 g 10:44 15-Oct Oxygen = 0,03885 % Nitrogen = 0,00426 % Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area

1 2 3 4 5 6 7 8

0-16 sec 16-64 sec 64-180 sec 180-236 sec 236-236 sec 236-300 sec 300-364 sec 364-395 sec

0,00000 % 0,00290 % 0,01738 % 0,00595 % 0,00005 % 0,00502 % 0,00615 % 0,00146 %

Oxygen = 0,03885 %

ID CODE: e-4 wt = 0,2590 g 11:03 15-Oct Oxygen = 0,04899 % Nitrogen = 0,00396 % Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area

1 2 3 4 5 6 7


0,00000 % 0,00318 % 0,01346 % 0,01564 % 0,00643 % 0,00958 % 0,00070 %

Oxygen = 0,04899 %

ID CODE: e-5 wt = 0,2773 g 11:23 15-Oct Oxygen = 0,05249 % Nitrogen = 0,00494 % Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area Oxygen Area

1 2 3 4 5 6 7


0,00000 % 0,00208 % 0,01505 % 0,02038 % 0,00820 % 0,00632 % 0,00047 %

Oxygen = 0,05249 %

Slika 2./nastavak/ - Distribucija kisika u metalu zavara, za uzorke zavarene u zatiti Ar/CO2 mjeavina sa 22

i 30 % CO,

t

2 i uzorke zavarene u zatiti Ar/O2 mjeavina sa 12 i14 % O2 [4] Figure 2./continuation/- Oxygen distribution in the weld metal of experimental samples welded in the

protection of Ar/CO2 gas mixtures with 22 and 30 % CO2, and samples welded in the protection of Ar/O2 gas mixtures with 12 and 14 % O2,

Tabela 4.- Temperature topljenja pojedinih oksida, prisutnih u metalu zavara Tabel 4. Melting tempera ure of particular oxides, present in the weld metal Vrsta oksida Type of oxide

Cu2O FeO Fe3O4 Fe2O3 MnO SiO2

Temperatura topljenja Temperature of melting

1235 oC 1420 oC 1538 oC 1595 oC 1650 oC 1710 oC

Analiza distribucije kisika po oksidima, ura|ena u okviru ovoga rada, na sedam karakteristi~nih uzoraka, zavarenih u razli~itim Ar/CO2 i Ar/O2 gasnim mjeavinama pokazala je, u veoj ili manjoj mjeri, prisustvo svih naprijed navedenih oksida u metalu zavara. Procentualno u~ee kisika vezanog u pojedinim oksidima u strukturi metala zavara navedeno je u tabelama uz dijagrame, slika 2.

Analysis of the oxygen distribution per oxides, carried out in this paper, on seven characteristic samples welded in the different Ar/CO2 and Ar/O2 gas mixtures has shown to some extent presence of all above mentioned oxides in weld metal. Percentage participation of oxygen connected in particular oxides in the structure of the weld metal is shown in the tables along with diagrams, figure 2.

Prema ovim podacima, koli~ine kisika vezanog za èljezni oksid (FeO), koji je vrlo vaàn za osobine metala zavara, kreu se od 0,00712% do 0,01738%, kisika vezanog u mangan-oksid (MnO) - od 0,00615% do 0,01123%, a koli~ine kisika vezanog za silicijum-dioksid (SiO2) su u granicama od 0,00070% do 0,00511%. Distribucija kisika prisutnog u metalu zavara eksperimentalnih uzoraka na pomenuta tri oksida moè se predstaviti i grafi~ki, slika 3.

Pursuant these data the quantity of oxygen connected in iron oxide (FeO), which is very important for the characteristics of weld metal, varies from 0,00712% to 0,01738%; of oxygen connected in manganese oxide (MnO) varies from 0,00615% to 0,01123%; and of oxygen connected in silicon dioxide (SiO2) - from 0,00070% to 0,00511%. The distribution of oxygen present in the weld metal, of experimental samples on three mentioned oxides can be presented graphically, figure 3.

0,035 0,040 0,045 0,0500,000

0,005

0,010

0,015

0,020

SiO2

MnO

količ

ina

kisi

ka v

ezan

og u

oks

idim

a

sadržaj kisika u metalu zavara u %

(

u %

f

Qua

ntit

y of

oxy

gen

conn

ecte

d in

oxi

des

in %

FeO

Oxygen content in weld metal in %

Slika 3.- Zavisnost koli~ine kisika vezanog u pojedinim oksidima FeO, MnO, SiO2) od sadràja kisika u metalu zavara [4]

Figure 3.- Dependence o oxygen quantity connected to particular oxides (FeO, MnO, SiO2) on oxygen content in the weld metal

Analizirajui dijagram moè se zaklju~iti da sa porastom sadràja oksidirajuih komponenti u zatitnom gasu, odnosno sa porastom oksidacionog potencijala zatitnog gasa, raste sadràj kisika u metalu zavara. Istovremeno, dolazi i do poveanja sadràja nepoèljnog èljeznog oksida (FeO). Sadràj mangana i silicija u metalu zavara se smanjuje, slika 1, to dovodi i do smanjenja ukupnog u~ea njihovih oksida u strukturi metala zavara. Ovakav trend porasta koncentracije èljeznog oksida FeO u strukturi metala zavara je nepovoljan i moè negativno da se odrazi na kona~ne osobine zavarenog spoja. Da bi se on ograni~io potrebno je ili upotrebljavati zatitne gasove sa relativno niìm oksidacionim potencijalom ili poveati sadràj dezoksidatora - mangana i silicija u elektrodnoj ìci. Na taj na~in bi se poveao intenzitet dezoksidacije i smanjio nivo prisustva nepoèljnog èljeznog oksida u strukturi metala zavara.

By analysing the diagram, it could be concluded that increase in contents of oxide components in the shielding gas, in other words increase of the oxygen potential of shielding gas, leads to increase of the oxygen content in the weld metal. At the same time content of undesirable iron oxide (FeO) increases. The contents of the manganese and the silicon in the weld metal is decreasing figure 1, which leads to lessening in total participation of their oxides in weld metal structure. This trend in increase of the iron oxide concentration FeO in weld metal structure is unfavourable and can negatively reflect on the final characteristics of welded joints. To limit its influence it is necessary to use shielding gases with relatively smaller oxidation potential or to enlarge the content of the deoxidisers - manganese and silicon in the filler wire. In that way, the intensity of the deoxydation would be bigger and the level of undesirable iron oxide in the weld metal structure would be reduced.

- 215 -

5. ZAKLJUÂK Na kraju, kao zaklju~ak, moè se konstatovati da je provedena analiza pokazala da sa promjenom sastava zatitnog gasa, odnosno promjenom koncentracije oksidirajuih komponenti u zatitnom gasu (CO2 ili O2), dolazi do promjene hemijskog sastava metala zavara. Porastom oksidacionog potencijala zatitnog gasa sadràj kisika u metalu zavara raste sadràj mangana i silicija opada, dok se koncentracija ugljika i azota mijenja neznatno. Poveana koncentracija kisika u metalu zavara uzrokuje poveanje koncentracije nepoèljnog èljeznog oksida FeO, to se moè negativno odraziti i na mikrostrukturu metala zavara i na mehani~ke osobine zavarenog spoja. Zbog toga je pri izboru zatitnog gasa optimalnog sastava potrebno voditi ra~una o njegovom oksidacionom potencijalu, ne samo sa aspekta stabilnog odràvanja elektri~nog luka i smanjenja koli~ine prskanja, nego se u vidu mora imati i intenzitet odvijanja oksidacionih reakcija u rastopljenom osnovnom i dodatnom metalu i zatitni gas birati tako da njegov oksidacioni potencijal bude uskla|en sa hemijskim sastavom odabranog dodatnog materijala.

5. CONCLUSION In the end, it could be stated as a conclusion, that the implemented analysis has shown that changing of the shielding gas composition, in other words changing of concentration of oxidation component in the shielding gas (CO2 or O2), leads to changing of weld metal chemical composition. Increasing the shielding gas oxidation potential, contents of the oxygen in the weld metal is bigger, contents of the manganese and silicon declines and the concentration of carbon and nitrogen varies, but very slightly. Increased concentration of the oxygen in the weld metal causes increase in concentration of undesirable iron oxide, FeO, which can negatively influence the microstructure of weld metal and mechanical characteristics of welded joints. Therefore when choosing the shielding gas with optimal composition, it is very important to consider its oxidation potential, not only from perspective of a stable maintenance of electric arc and loss spatter reduction but it is necessary to take in account the intensity of oxidation reactions in the molten metal. Thus shielding gas must be chosen in that way that oxidation potential of shielding gas is harmonized with chemical composition of the chosen filler wire.

6. LITERATURA - REFERENCES

[1] Onsoien M.I., Liu S., Olson D.L.: “Shielding Gas Oxygen Equivalent in Weld Metal Microstructure Optimization”, Welding Journal, July 1996.,

[2] Luijendik T.: “Influence of Shielding Gas Composition on Features of the GMA Welding Process”, IIW Dok. XII-1343-93,

[3] Ushio M., Ikeuchi K., Tanaka M., Seto T.: “Effects of Shielding Gas Composition on Metal Transfer Phenomena in High Current GMA Welding”, Trans. of JWRI, Vol.22, No.1, August 1993,

[4] Pai S.: “Doprinos istaìvanju uticaja zatitnog gasa na proces zavarivanja MIG/MAG postupkom u visokom reìmu

parametara zavarivanja”, Doktorska disertacija, Sarajevo, Decmebar 1999.

[5] Stenbacka N., Persson K.A.: “Shielding Gases for Gas Metal Arc Welding”, Welding Journal, November 1989.,

[6] Lucas W.: “Shielding Gases for Arc Welding”, Welding & Metal Fabrication, June 1992,

[7] Schuman H.: “Metalografija”, Leipzig, 1962,

[8] Jonnson P.G., Murphy A.B., Szekely J.: “The Influence of Oxygen Addtions on Argon-Shielded Gas Metal Arc Welding Processes”, Welding Research Supplement, Feb.1995.,

- 216 -

Mainstvo 4 (5), 217 – 228, (2001) M.Bijedi,...: RAZMATRANJE INTEGRALNOG JOULE-THOMSONOVOG...

RAZMATRANJE INTEGRALNOG JOULE-THOMSONOVOG EFEKTA IZ JEDNA^INE STANJA SOAVE-BENEDICT-WEBB-RUBINA

Dr. sci. Muhamed Bijedi, docent, Tehnoloki fakultet Tuzla, Bosna i Hercegovina Enver \idi, dipl. ing., BNT-TMiH, Novi Travnik, Bosna i Hercegovina REZIME

U ovom radu razvijen je postupak za ra~unanje integralnog Joule-Thomsonovog efekta iz jedna~ine stanja Soave-Benedict-Webb-Rubina (SBWR). Izvedene su korelacije za integralnu i diferencijalnu inverzionu krivu u Pr-Tr koordinatama du` kojih izotermski (∆hT) i izentalpski (∆Th)

rt

- -

)r ( )

r rr r- ) .

integralni Joule-Thomsonov efekat ima minimalne odnosno maksimalne v ijednosti. Ove korelacije su testirane na primjerima argona, azo a i metana u intervalu Pr od 0 do 70 i Tr od 0 do 5. Dobijeni rezultati upore|eni su s eksperimentalno potvr|enim podacima i sa onima dobijenim jedna~inama stanja Soave Redlich-Kwonga (SRK) i Peng Robinsona (PR).

IZVORNI NAU^NI RAD

Klju~ne rije~i: Joule-Thomsonov efekat, termodinamika, matemati~ki modeli

MEDITATION OF INTEGRAL JOULE-THOMSON EFFECT FROM SOAVE-BENEDICT-WEBB-RUBIN EQUATION OF STATE Muhamed Bijedi, Ph.D., Faculty of Technology, Tuzla, Bosnia and Herzegovina Enver \idi, B.Sc., BNT-TMiH, Novi Travnik, Bosnia and Herzegovina SUMMARY In this paper the procedure for calculation of integral Joule-Thomson effect from Soave-Benedict-Webb-Rubin (SBWR equation of state is developed. Correlations are derived for integral and differential inversion curves in Pr-T plane along which isothermal ∆hT) and isenthalpic (∆Th integral Joule-Thomson effects have minimum and maximum values, respectively. These correlations a e tested on the examples of a gon, nitrogen and methane in the ranges of P 0-70 and Tr 0-5. The results are compa ed with experimentally verified data and to those obtained by Soave Redlich-Kwong (SRK) and Peng-Robinson (PR equations of state

ORIGINAL SCIENTIFIC PAPER

Key words: Joule-Thomson effect, thermodynamics, mathematical models 1. UVOD Joule-Thomsonov (J-T) efekat1 dobro je poznat i iroko je prou~avan. Sa prakti~ne ta~ke gledita, me|utim, adijabatsko priguivanje u direktnoj je vezi s integralnim J-T efektom, koji je zato va`niji projektni parametar. Mnoge aplikacije u potpunosti su zasnovane na integralnom J-T efektu. Na primjer, J-T kriogeni hladnjaci2 i sistemi za otekuavanje3 direktno su ovisni od ukupnog temperaturnog pada pri ekspanziji gasa od visokog po~etnog pritiska do pritiska okoline. Ipak, integralni J-T efekat nedovoljno je iroko prou~avan. Ova bitna informacija data je implicitno u diferencijalnom J-T koeficijentu koji se definira kao

1. INTRODUCTION The Joule-Thomson (J-T) effect1 is well known and has been extensively studied. From a practical point of view, however, adiabatic throttling relates directly to the integral J-T effect, which is, therefore, a more important design parameter. Many applications are completely ruled by the integral effect. For instance, J-T cryocoolers2 and liquefaction systems3 are directly affected by the total temperature drop while the gas expands from the initial high pressure to that of the surroundings. Nevertheless, the integral effect has been less extensively studied. Indeed, the relevant information is implicit in the differential J-T coefficient, which is defined as

- 217 -


hJ P

T

∂∂

=µ (1)

i moè se dobiti integriranjem du` linije konstantne entalpije. Za realni gas, me|utim, ovim integriranjem ne moè se izvesti kona~ni izraz, to zahtijeva numeri~ko integriranje ta~ku po ta~ku. Alternativno, integralni J-T efekat daje se preko izotermske promjene entalpije

pcPh

JT

µ−=

∂∂

(2)

Diferencijalni J-T koeficijent definira se preko termodinami~kih svojstava, pa je i sam svojstvo supstance. Zna~aj diferencijalnog J-T koeficijenta moè se demonstrirati posmatranjem procesa priguivanja koji rezultira padom pritiska. Ovaj proces spada u grupu tzv. "steady state, steady-flow" procesa4. To su procesi koji ispunjavaju slijedee uslove: 1) Kontrolni volumen ne kree se u odnosu na koordinatni okvir; 2) Stanje mase u svakoj ta~ki kontrolnog volumena ne mijenja se sa vremenom; 3) Tok mase i njeno stanje u svakoj ta~ki toka na kontrolnoj povrini ne mijenja se sa vremenom. Tipi~an primjer je proticanje kroz djelimi~no otvoren ventil ili kroz suènje u cjevovodu. U veini slu~ajeva to se deava tako brzo i na tako malom prostoru da nema dovoljno vremena niti dovoljno velike povrine za veliki prenos topline. Zato se takvi procesi obi~no smatraju adijabatskim. Tokom takvih procesa ne proizvodi se nikakav rad, ne mijenja se ni potencijalna energija i ne izmjenjuje se nikakva toplina. Na osnovu tih postavki energetska jedna~ina jednog takvog procesa imala bi oblik

22

2i

i

2u

uwhwh +=+ (3)

gdje se indeksi u i i odnose na ulaz odnosno izlaz iz kontrolnog volumena. Ako je fluid gas onda njegov specifi~ni volumen uvijek raste u takvom procesu, pa ako je cjevovod konstantnog dijametra, kineti~ka energija fluida raste. U mnogim slu~ajevima, me|utim, ovaj porast kineti~ke energije je mali, pa se moè rei da su u ovom procesu po~etna i kona~na entalpija jednake, tj.

hu=hi (4) Pozitivan diferencijalni J-T koeficijent, J, zna~i da temperatura opada tokom priguivanja, a kada je diferencijalni J-T koeficijent negativan temperatura raste tokom priguivanja.

hJ P

T

∂∂

=µ (1)

and can be obtained by integration along a constant enthalpy line. For a real gas, however, this integration can not be given in a closed form and requires laborious point by point numerical integration. Alternatively, integral J-T effect is given in terms of the isothermal enthalpy change

pcPh

JT

µ−=

∂∂

(2)

This quantity is defined in terms of thermodynamic properties, and therefore is itself a property of a substance. The significance of the differential J-T coefficient may be demonstrated by considering a throttling process, with a resulting drop in pressure. This process is a steady state, steady-flow process across a restriction4. This group of processes meets the next conditions: 1) The control volume does not move relative to the coordinate frame; 2) The state of the mass at each point in the control volume does not vary with time; 3) The mass flux and the state of this mass at each discrete area of flow on the control surface do not vary with time. A typical example is the flow through a partially opened valve or a restriction in the line. In most cases this occurs so rapidly and in such a small space, that there is neither sufficient time nor a large enough area for much heat transfer. Therefore, we usually may assume such processes to be adiabatic. During such processes there is no work, no change in potential energy, and we make the reasonable assumption that there is no heat transfer. On the basis of these assumptions energy equation of such process would have a form

22

2i

i

2u

uwhwh +=+ (3)

where subscripts u and i refer to the input and output of the control volume, respectively. If the fluid is gas, the specific volume always increases in such a process, and, therefore, if the pipe is of constant diameter, the kinetic energy of the fluid increases. In many cases, however, this increase in kinetic energy is small and we can say that in this process the final and initial enthalpies are equal, that is

hu=hi (4) A positive differential J-T coefficient, J, means that the temperature drops during throttling, and when it is negative the temperature rises during throttling.

- 218 -


2. INTEGRALNA INVERZIONA KRIVA Izentalpski integralni J-T efekat5 ∆Th definira se kao promjena temperature pri izentalpskoj ekspanziji od po~etnog pritiska P do pritiska okoline P0≈0

( ) (( ) ( )hThPT

hPThPTT,,

,,h

012

012

−≅−=∆ )

)

(5)

i moè se korelirati sa diferencijalnim J-T koeficijentom integriranjem du` izentalpske krive

( )hP J PTPT

=∆ ∫

0

h d,µ (6)

Izotermski integralni J-T efekat5 ∆hT definira se kao promjena entalpije pri izotermskoj ekspanziji od po~etnog pritiska P do pritiska okoline P0≈≈0

( ) ( )( ) ( )[ ] ( ) ( )[ ]TPhTPhThTh

TPhThh

,,,,

,,IGRIGR

T

−−−

=−=∆

00

0 7)

Poto je hIG(P,T)=hIG(0,T) i hR(0,T)=0, proizilazi da je

( TPhh ,RT −=∆ (8)

Rezidualna entalpija hR(P,T) moè se izra~unati iz jedna~ine stanja date supstance. Za realne gasove egzaktna jedna~ina stanja daje se numeri~ki ili empirijski. Prora~uni se, dakle, moraju izvesti numeri~ki. Izraz za izotermsku promjenu entalpije realnih gasova6, izveden iz SBWR jedna~ine stanja7, ima oblik

2. INTEGRAL INVERSION CURVE The isenthalpic integral J-T effect5 ∆Th is defined as the temperature change in an isenthalpic expansion from the initial pressure P to that of the surroundings P0≈≈

)

)

0

( ) (( ) ( )hThPT

hPThPTT,,

,,h

012

012

−≅−=∆

(5)

which may be related to the differential J-T coefficient by integration along isenthalpic curve

( )hP J PTPT

=∆ ∫

0

h d,µ (6)

The isothermal integral J-T effect5 ∆hT is defined as the enthalpy change in an isothermal expansion from the initial pressure P to that of the surroundings P0≈≈0

( ) ( )( ) ( )[ ] ( ) ( )[ ]TPhTPhThTh

TPhThh

,,,,

,,IGRIGR

T

−−−

=−=∆

00

0 (7)

Since hIG(P,T)=hIG(0,T) and hR(0,T)=0, it follows that

( TPhh ,RT −=∆ (8)

The residual enthalpy hR(P,T) is calculable from the equation of state of the substance. For real gases the exact equation of state is given numerically or by empirical equations. Calculations must, therefore, be carried out numerically. The expression for isothermal enthalpy change of real gases6 is derived from SBWR equation of state7, and have the form

( )

( )RTPvTT

eT

ee

RTRT

TTc

TccRT

Tb

TbRTh

−−

+−−

−−−−

⋅

−−

+−−

+−−

−−−−+

++

++−=∆

13211

12

14

132112

221601

233221

224

233221

2

232611

rrrc

rrrc

.r

.r

cT

exp

..

εε

φψφψ

φδ

ψ

γγψ

ωββψ

(9)

Integralna inverziona kriva moè se definirati kao skup svih ta~aka iz kojih je integralna promjena temperature nula. Integralna inverziona kriva data je jednim od naredna dva oblika

∆Th=0 ili ∆hT=0 (10) Generalizirana korelacija (sa faktorom korelacije 0.993) za integralnu inverzionu krivu, koja odgovara eksperimentalno potvr|enim termodinami~kim podacima8 za N2, Ar, CO i CH4, je

2410644510502305 rrr ... PpT −⋅+−= (11)

Integral inversion curve may be defined as the locus of all points from which the integral temperature change is zero. The integral inversion curve is given by either of the two forms

∆Th=0 or ∆hT=0 (10) A generalized correlation (with a 0.993 correlation factor) for the integral inversion curve, that fits experimentally verified thermodynamic data8 for N2, Ar, CO and CH4, is

2410644510502305 rrr ... PpT −⋅+−= (11)

- 219 -


Za veinu prakti~nih namjena, sa pritiscima koji nisu isuvie visoki, Pr<40, jedna~ina

rr 105.0230.5 PT −= (12)

e obezbijediti adekvatnu aproksimaciju.

For most practical purposes, with pressures which are not too high, Pr<40, the equation

rr 105.0230.5 PT −= (12)

will provide an adequate approximation.

3. DIFERENCIJALNA INVERZIONA KRIVA Skup svih ta~aka u kojima nestaje diferencijalni J-T koeficijent (µJ=0) naziva se diferencijalnom inverzionom krivom. Maksimalne vrijednosti ∆hT pri bilo kojoj zadatoj temperaturi javljaju se u presjeku te izoterme sa diferencijalnom inverzionom krivom. Poto je ∆hT funkcija od P, v i T, a iz SBWR jedna~ine8 je

3. DIFFERENTIAL INVERSION CURVE The locus of all points for which the differential J-T coefficient vanishes (µJ=0) is called the differential inversion curve. Maximum values of ∆hT at any given temperature occur at the intersection of the isotherm with the differential inversion curve. As ∆hT is function of P, v and T, and from SBWR equation8 is

−⋅

+++++= 22242 11

vF

vF

vE

vD

vC

vB

vRTP exp (13)

zamjenom jedna~ine (13) u jedna~inu (9) i diferenciranjem rezultirajue jedna~ine po v, kada je T konstantno, dobije se

by changing equation (13) into equation (9) and by differentiation of resulting equation upon v, when T is constant, following expression is obtained

−

+−

−+

−

++++

−

+−−

−−−−

−

+−

−−

−−

+−−

−−−−

⋅+

++

++−=

∂∆∂

22

22

22

22

43

44

22

22

43

44

22

22

22

22

2

22

43

44

2

22

233221

22

22

2

22

22

22

22

22

2

22

43

45

233221

2

23

232611

2

122

1242

13211

212

13211

221601

c

c

c

c

c

c

c

c

c

c

c

c

c

c

c

c

c

c

c

c

c

c

rrrc

c

c

c

c

c

c

c

c

c

c

c

c

rrrc

c

c.

r.

rc

c

cT

expexp

exp

expexp

..

PvTR

PvTR

PvTR

PvTR

PvTR

PvTR

PvTR

vPTR

PvTR

vPTR

PRT

RT

TTe

Tee

PvTR

vPTR

PvTR

PvTR

vPTRRT

PvTTR

TTc

Tcc

vPTTR

Tb

Tb

PTTR

vh

T

φφ

φεφφ

ε

φφεδγβ

εε

φφφφφφ

δγγ

ωββ

(14)

Kada se desna strana izraza (14) izjedna~i sa nulom, pa se iz dobijenog izraza izra~una v, a onda iz jedna~ine (13) P, dobije se za zadatu temperaturu T pritisak pri kojem e ∆hT imati maksimalnu vrijednost. Numeri~ke vrijednosti ∆hTmax ra~unaju se iz jedna~ine (9). Maksimalne vrijednosti ∆Th sada se mogu izra~unati iz jedna~ine (5). Entalpija realnog gasa u stanju (P,T2) je

h=hIG(0,T2)+hR(P,T2) (15)

When right side of expression (14) is equal zero, and resulting equation is solved upon v, and equation (13) is solved upon P, for the given temperature T we obtain pressure at which ∆hT will have maximum value. Numerical values of ∆hTmax are calculated from equation (9). Maximum values of ∆Th , now, can be calculated from equation (5). Real gas enthalpy in state (P,T2) is

h=hIG(0,T2)+hR(P,T2) (15)

- 220 -


a entalpija idealnog gasa u stanju (P0,T1)

h=hIG(0,T1)+hR(0,T1) (16)

Imajui u vidu jedna~inu (4) i ~injenicu da je hR(0,T1)=0, onda je

h=hIG(0,T1) (17)

Entalpija idealnog gasa funkcija je samo od temperature i ima oblik9

and ideal gas enthalpy in state (P0,T1)

h=hIG(0,T1)+hR(0,T1) (16)

Having in mind equation (4) and the fact that hR(0,T1)=0, it follows

h=hIG(0,T1) (17)

Ideal gas enthalpy is function of temperature only and has the form9

( ) ( ) ( ) ( ) ( 40

41

30

31

20

21011 432

0 TTdTTcTTbTTaTh −+−+−+−=,IG ) (18)

Rjeavanjem jedna~ine (18) po temperaturi T1 dobije se maksimalni pad temperature izentalpskom ekspanzijom

Thmax=T2-T1 (19)

Eksperimentalne podatke za diferencijalne inverzione krive realnih gasova sa niskim Pitzerovim faktorom acentri~nosti korelirali su Gunn i dr.10

Solving equation (18) upon temperature T1 maximum temperature drop during isenthalpic expansion is obtained

Thmax=T2-T1 (19)

Experimental data for the differential inversion curves of real gases with a low acentric factor were correlated by Gunn et al.10

5432 09116706721182611567415987127536 rrrrrr ...... TTTTTP +−+−+−= (20)

Alternativnu korelaciju predlo`io je Miller11

2825054182124 rr

r ..

. TT

P −−= (21)

Iz nekih ta~aka na diferencijalnoj inverzionoj krivoj ekspanzija e se odvijati samo kroz gasovitu fazu, dok e iz drugih ta~aka sa ove krive doi do fazne promjene tokom ekspanzije. U P-h ili h-s koordinatama izentalpa koja dodiruje liniju zasienja kod jednokompo-nentnog fluida, odnosno liniju rosita kod vieko-mponentnog fluida, predstavlja granicu izme|u ova dva tipa procesa12. Sve ta~ke na diferencijalnoj inverzionoj krivoj u kojima fluid ima veu entalpiju od ove entalpije imaju za rezultat jednofaznu ekspanziju, a one ta~ke na ovoj krivoj u kojima fluid ima manju entalpiju od navedene rezultirae promjenom faze tokom ekspanzije.

An alternative correlation was proposed by Miller11

2825054182124 rr

r ..

. TT

P −−= (21)

Certain points on differential inversion curve will result in expansion through single gaseous phase only, while others may pass through a phase change in the course of expansion. In P-h or h-s coordinates isenthalpic curve touching saturation line of pure compound, or dew line of mixture, denotes border between the two types of processes12. All the points on differential inversion curve with higher enthalpy result in single-phase expansion and those with lower enthalpy result in phase change during expansion.

4. REZULTATI Na slici 1 prikazane su integralna inverziona kriva (∆hT=0) i diferencijalna inverziona kriva (∆hTmax) u koordinatama Pr-Tr, za raspon redukovanog pritiska 0-70 i redukovane temperature 0-5, za argon. Isprekidana linija predstavlja izentalpu koja dijeli stanja fluida iz kojih zapo~inje ekspanzija samo kroz gasovitu fazu, od stanja iz kojih ekspanzija rezultira faznom promjenom. Integralna i diferencijalna inverziona kriva dobijene su SBWR jedna~inom stanja koritenjem izraza (9), (10) i (14). Vrijednost grani~ne entalpije dobijena je SBWR jedna~inom stanja i predstavlja maksimalnu entalpiju (hmax) zasiene pare fluida. Da bi se ova izentalpa prikazala u Pr-Tr koordinatama Pr se mijenja od 0 do 70, a T odnosno Tr ra~una se iz jedna~ine

4. RESULTS Figure 1 shows integral inversion curve (∆hT=0) and differential inversion curve (∆hTmax) in Pr-Tr plane, for reduced pressure range 0-70 and reduced temperature range 0-5, for argon. Dashed line represents isenthalpic curve, which separates fluid states resulting in single gaseous phase expansion, from states resulting in phase change during expansion. Integral and differential inversion curves are obtained from SBWR equation of state using expressions (9), (10) and (14). Value of limiting enthalpy is obtained from SBWR equation of state and it represents maximum enthalpy (hmax) of saturated vapor. In order to represent this isenthalpic curve in Pr-Tr plane, Pr is changed from 0 to 70, and T or Tr is calculated from next equation

- 221 -


h[P,T,v(P,T)]-hmax=0 (22) Na slici 2 prikazane su integralne inverzione krive za argon, za raspon redukovanog pritiska 0-70 i redukovane temperature 0-5. Isprekidana linija predstavlja integralnu inverzionu krivu ra~unatu po jedna~ini (11). Kriva sa oznakom SBWR dobijena je iz SBWR jedna~ine stanja koritenjem izraza (9) i (10). Preostale dvije linije predstavljaju integralne inverzione krive dobijene iz jedna~ina stanja Soave-Redlich-Kwonga (SRK) i Peng-Robinsona (PR), na isti na~in kao i u slu~aju SBWR jedna~ine. Sa slike se vidi da integralna inverziona kriva dobijena SBWR jedna~inom stanja najbolje prati integralnu inverzionu krivu zasnovanu na eksperimentalnim podacima, u cijelom posmatranom intervalu Pr i Tr. Najloiji rezultati dobijeni su PR jedna~inom stanja, dok je SRK jedna~ina stanja neto bolja od nje.

h[P,T,v(P,T)]-hmax=0 (22) Figure 2 shows integral inversion curves for argon, for reduced pressure range 0-70 and reduced temperature range 0-5. Dashed line represents integral inversion curve calculated from equation (11). Curve denoted with SBWR is obtained from SBWR equation of state using expressions (9) and (10). Two remaining lines represent integral inversion curves obtained from Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR) equations of state, in the same way as in the case of SBWR equation. From the figure 2 it is seen that integral inversion curve obtained by SBWR equation of state fits integral inversion curve based on experimental data the best, in whole range of Pr and Tr. The worst results are obtained by PR equation of state, while SRK equation of state is slightly better.

lSlika 1. Integralna i diferencija na inverziona kriva za Ar iz SBWR jedna~ine stanja

Figure 1. Integral and differential inversion curves for Ar from SBWR equation of state

Slika 2. Integralne inverzione krive za Ar po razli~itim metodama

Figure 2. Integral inversion curves for Ar upon different methods

Na slici 3 prikazane su integralne inverzione krive za Ar, N2 i CH4, dobijene SBWR jedna~inom stanja. Kako se sa slike vidi krive za razli~ite fluide podudaraju se u cijelom posmatranom intervalu Pr i Tr. Koeficijenti korelacija koje aproksimiraju te krive dati su u tabeli 1. Na slici 4 prikazane su integralne inverzione krive sa slike 3, ali sada u P-T koordinatama. Za razliku od krivih sa slike 3 ove krive odstupaju jedna od druge, ali ipak imaju sli~ne oblike, to se moglo i o~ekivati iz zakona o korespondentnim stanjima.

Figure 3 shows integral inversion curves for Ar, N2 and CH4, obtained by SBWR equation of state. As the figure shows, curves for different fluids coincide in the whole range of Pr and Tr. The coefficients of correlations approximating these curves are given in table 1. Figure 4 shows integral inversion curves from figure 3, but now in P-T plane. In contrast to the curves from figure 3 these curves do not coincide, but still have similar shapes, which one could expect from the law of corresponding states.

- 222 -


Tabela 1. Korelacije za integralnu inverzionu krivu u P -T koordinatama r rTable 1. Correlations for integral inversion curve in Pr-Tr plane Oblik zavisnosti (Type of dependency): Pr=A0+A1Tr+A2Tr2+A3Tr3+…+AnTrn Ar (Tr = 0.4-4.9) N2 (Tr = 0.65-4.6) CH4 (Tr = 0.5-5.0) A0 6.61553E1 9.59584E1 8.80033E1 A1 6.43269E1 -5.27567E1 -4.52830E1 A2 -2.21669E2 2.19511E1 1.93123E1 A3 2.81247E2 -5.48895E0 -5.03235E0 A4 -2.02289E2 4.85294E-1 4.55698E-1 A5 8.96755E1 A6 -2.49817E1 A7 4.25315E0 A8 -4.03502E-1 A9 1.63194E-2

F F

Na skrive i redpredspo dobijizrazadiferestanjaRobinSBWRinverzi PRzasnointervSBWRNajlou cije

Slika 3. Integralne inverzione krive za Ar, N2 i CH4 po SBWR jedna~ini stanja

igure 3. Integral inversion curves for Ar, N2 andCH4 upon SBWR equation o sta e f t

lici 5 prikazane su diferencijalne inverzione za argon, za raspon redukovanog pritiska 0-14 ukovane temperature 0-5. Isprekidana linija tavlja diferencijalnu inverzionu krivu ra~unatu jedna~ini (21). Kriva sa oznakom SBWR ena je iz SBWR jedna~ine stanja koritenjem (14). Preostale dvije linije predstavljaju ncijalne inverzione krive dobijene iz jedna~ina Soave-Redlich-Kwonga (SRK) i Peng-sona (PR), na isti na~in kao i u slu~aju jedna~ine. Sa slike se vidi da diferencijalne ione krive dobijene jedna~inama stanja SBWR najbolje prate diferencijalnu inverzionu krivu vanu na eksperimentalnim podacima, u alu Tr od 0-2.4, dok u intervalu Tr 2.4-5.0 jedna~ina stanja daje najboje rezultate. iji rezultati dobijeni su SRK jedna~inom stanja lom posmatranom intervalu Pr i Tr.

FigargredrepfroobexpdifReeqof thaancuran5.0Thof

- 223 -

Slika 4. Integralne inverzione krive za Ar, N2 i CH4 u P-T koordinatama

igure 4. Integral inversion curves for Ar, N2 and CH4 in P-T plane

ure 5 shows differential inversion curves for on, for reduced pressure range 0-14 and uced temperature range 0-5. Dashed line resents differential inversion curve calculated m equation (21). Curve denoted with SBWR is tained from SBWR equation of state using ression (14). Two remaining lines represent ferential inversion curves obtained from Soave-dlich-Kwong (SRK) and Peng-Robinson (PR) uations of state, in the same way as in the case SBWR equation. From the figure 5 it is seen t differential inversion curves obtained by SBWR d PR equations of state fit differential inversion rve based on experimental data the best, in the ge of Tr 0-2.4. However, in the range of Tr 2.4- SBWR equation of state gives the best results. e worst results are obtained using SRK equation state in the whole range of Pr and Tr.


- 224 -

Na slici 6 prikazane su diferencijalne inverzione krive za Ar, N2 i CH4, dobijene SBWR jedna~inom stanja. Kako se sa slike vidi krive za razli~ite fluide podudaraju se skoro u cijelom posmatranom intervalu Pr i Tr. Koeficijenti korelacija koje aproksimiraju te krive dati su u tabeli 2. Na slici 7 prikazane su diferencijalne inverzione krive sa slike 6, ali sada u P-T koordinatama. Za razliku od krivih sa slike 6 ove krive odstupaju jedna od druge, ali ipak imaju sli~ne oblike, to se, tako|er, moglo o~ekivati iz zakona o korespondentnim stanjima.

Figure 6 shows differential inversion curves for Ar, N2 and CH4, obtained by SBWR equation of state. As the figure shows curves for different fluids coincide in almost the whole range of Pr and Tr. The coefficients of correlations approximating these curves are given in table 2. Figure 7 shows differential inversion curves from figure 6, but now in P-T plane. In contrast to the curves from figure 6 these curves do not coincide, but still have similar shapes, which one could expect from the law of corresponding states.

400

500

600

700

0.0 1.0 2.0 3.0 4.0 5.0

Tr

0

1000

4000

5000

6000

7000

Slika 5. Diferencijalne inverzione krive za Ar po razli~itim metodama

Figure 5. Differential inversion curves for Ar upon different methods

Slika 6. Diferencijalne inverzione krive za Ar, N2 i CH4 po SBWR jedna~ini stanja

Figure 6. Differential inversion curves for Ar, N2 and CH4 upon SBWR equation of state

2000

3000

∆hT

maxkJ/kmol

Ar

N2

CH4

0 200 400 600 800 1000

T, K

0

100

200

300Pbar

ArN2

CH4

Slika 8. Zavisnost hTmax od Tr za Ar, N2 i CH4 po SBWR jedna~ini stanja

Figure 8. hTmax vs. Tr for Ar, N2 i CH4 upon SBWR equation o sta e f t

Slika 7. Diferencijalne inverzione krive za Ar, N2 i CH4 u P-T koordinatama

Figure 7. Differential inversion curves for Ar, N2 and CH4 in P-T plane


Na slici 8 prikazana je zavisnost maksimalnih vrijednosti izotermskog integralnog J-T efekta, ∆hTmax, od redukovane temperature, za Ar, N2 i CH4. Vrijednosti su dobijene SBWR jedna~inom stanja iz izraza (9), za Pr i Tr du` diferencijalne inverzione krive dobijene istom jedna~inom stanja. Koeficijenti korelacija koje aproksimiraju rezultate dobijene SBWR jedna~inom stanja dati su u tabeli 3. Na slici 9 prikazana je zavisnost maksimalnih vrijednosti izentalpskog integralnog J-T efekta, ∆Thmax, od redukovane temperature, za Ar, N2 i CH4. Vrijednosti su dobijene SBWR jedna~inom stanja po postupku opisanom izrazima (15) do (19), za Pr i Tr du` diferencijalne inverzione krive dobijene istom jedna~inom stanja. Koeficijenti korelacija koje aproksimiraju rezultate dobijene SBWR jedna~inom stanja dati su u tabeli 4.

Figure 8 shows dependency of maximum values of isothermal integral J-T effect, ∆hTmax, from reduced temperature, for Ar, N2 and CH4. These values are obtained by SBWR equation of state from expression (9), for Pr and Tr along differential inversion curve obtained by the same equation of state. The coefficients of correlations approximating results obtained by SBWR equation of state are given in table 3. Figure 9 shows dependency of maximum values of isenthalpic integral J-T effect, ∆Thmax, from reduced temperature, for Ar, N2 and CH4. These values are obtained by SBWR equation of state upon the procedure described by expressions (15) to (19), for Pr and Tr along differential inversion curve obtained by the same equation of state. The coefficients of correlations approximating results obtained by SBWR equation of state are given in table 4.

Slika 9. Zavisnost Thmax od T za Ar, Nr

r

r r

2 i CH4 po SBWR jedna~ini stanja Figure 9. Thmax vs. T for Ar, N2 i CH4 upon SBWR equation of state

Tabela 2. Korelacije za diferencijalnu inverzionu krivu u P -T koordinatama Table 2. Correlations for differentialal inversion curve in Pr-Tr plane Oblik zavisnosti (Type of dependency): Pr=A0+A1Tr+A2Tr2+A3Tr3+…+AnTrn Ar (Tr = 0.9-4.9) N2 (Tr = 0.9-4.6) CH4 (Tr = 0.9-4.9) A0 -4.31726E1 -4.61673E1 -3.93610E1 A1 1.01808E2 1.06481E2 8.77896E1 A2 -8.96209E1 -8.75348E1 -6.87442E1 A3 4.76042E1 4.07283E1 3.16223E1 A4 -1.52851E1 -1.07591E1 -8.49087E0 A5 2.79804E0 -7.83974E-2 1.18253E0 A6 -2.66100E-1 -6.54655E-2 A7 1.01276E-1

- 225 -


Tabela 3. Korelacije za hTmax, kJ/kmol, u zavisnosti od Tr Table 3. Correlations for hTmax, kJ/kmol, depending of T rOblik zavisnosti (Type of dependency): hTmax=A0+A1Tr+A2Tr2+…+AnTrn Ar (Tr = 0.9-4.9) N2 (Tr = 0.9-4.6) CH4 (Tr = 0.9-4.9) A0 1.18829E4 1.01656E4 1.53655E4 A1 -1.21171E4 -9.55161E3 -1.58510E4 A2 7.25961E3 4.68870E3 9.48993E3 A3 -2.88744E3 -1.41165E3 -3.73606E3 A4 6.81502E2 2.29055E2 8.71112E2 A5 -8.43725E1 -1.48574E1 -1.06601E2 A6 4.21592E0 5.26966E0

Tabela 4. Korelacije za Thmax, K, u zavisnosti od Tr Table 4. Correlations for Thmax, K, depending of Tr Oblik zavisnosti (Type of dependency): Thmax=A0+A1Tr+A2Tr2+…+AnTrn Ar (Tr = 0.9-4.9) N2 (Tr = 0.9-4.6) CH4 (Tr = 0.9-4.9) A0 4.83321E2 3.10768E2 6.65377E3 A1 -3.33899E2 -2.70058E2 -2.37180E4 A2 8.36974E1 1.26083E2 3.97923E4 A3 -8.82527E0 -3.80213E1 -3.95866E4 A4 3.14747E-1 6.31375E0 2.54831E4 A5 -1.10342E4 A6 3.24884E3 A7 -6.42043E2 A8 8.15335E1 A9 -6.01254E0 A10 1.95701E-1

5. ZAKLJUÂK Iz dobijenih rezultata moè se zaklju~iti da SBWR jedna~ina stanja dobro opisuje uslove pri kojima integralni J-T efekat ima ekstremne vrijednosti. Imajui u vidu da je pokriven veliki raspon redukovanog pritiska i redukovane temperature moè se rei da je odstupanje izra~unatih vrijednosti izentalpskog i izotermskog integralnog J-T efekta, od onih eksperimentalno potvr|enih, koritenjem ove jedna~ine stanja, prihvatljivo. SBWR jedna~ina stanja opisuje integralnu inverzionu krivu daleko bolje od jedna~ina stanja SRK i PR u cijelom posmatranom intervalu redukovanog pritiska i redukovane temperature. Diferencijalnu inverzionu krivu SBWR jedna~ina stanja bolje opisuje od PR jedna~ine stanja pri redukovanim temperaturama veim od 2.4, dok ovu krivu SRK jedna~ina stanja dobro opisuje samo u uskom intervalu redukovane temperature i to od 0.9 do 1.2.

5. CONCLUSION From the results obtained it can be concluded that SBWR equation of state describes well the conditions where integral J-T effect has extreme values. Having in mind broad ranges of reduced pressure and reduced temperature covered it can be said that deviation of calculated values of isenthalpic and isothermal integral J-T effects, from those verified experimentally, using this equation of state, is acceptable. SBWR equation of state describes integral inversion curve much better than SRK and PR do, in the whole range of reduced pressure and reduced temperature. Differential inversion curve is described by SBWR equation of state much better than by PR equation of state at reduced temperatures higher than 2.4, and this curve is described by SRK equation of state well in narrow range of reduced temperature only, it is 0.9 to 1.2.

- 226 -


6. SIMBOLI - SYMBOLS a, b, c, d – koeficijenti polinoma temperaturne zavisnosti cp idealnog gasa – coefficients of the cp=f(T) equation in ideal gas state B, C, D, E, F – parametri jedna~ine stanja u izrazu (13) – equation of state parameters in expression (13) b1, b2 – koeficijenti u jedna~inama (9) i (14) – coefficients in equations (9) and (14) c1, c2, c3 – koeficijenti u jedna~inama (9) i (14) – coefficients in equations (9) and (14) cp – toplotni kapacitet, kJ/kmolK – heat capacity, kJ/kmolK e1, e2, e3 – koeficijenti u jedna~inama (9) i (14) – coefficients in equations (9) and (14) h – entalpija, kJ/kmol – enthalpy, kJ/kmol P – apsolutni pritisak, kPa – absolute pressure, kPa R – gasna konstanta, kJ/kmolK – gas constant, kJ/kmolK s – entropija, kJ/kmolK – entropy, kJ/kmolK T – temperatura, K – temperature, K v – volumen, m3/kmol – volume, m3/kmol w – brzina, m/s – velocity, m/s Z – faktor kompresibilnosti – compressibility factor ∆hT – izotermski integralni Joule-Thomsonov efekat, kJ/kmol – isothermal integral Joule-Thomson effect, kJ/kmol ∆Th – izentalpski integralni Joule-Thomsonov efekat, K – isenthalpic integral Joule-Thomson effect, K µϑ – diferencijalni Joule-Thomsonov koeficijent, K/Pa – differential Joule-Thomson coefficient, K/Pa ψ, β, γ, δ, ε, – redukovani parametri jedna~ine stanja u izrazu (9) (vidi dodatak) – reduced parameters of equation of state in expression (9) (see appendix) ρ – gustina, kmol/m3 – density, kmol/m3 ω – Pitzerov faktor acentri~nosti – Pitzer's acentric factor

INDEKSI - SUBSCRIPTS 0 – referentno stanje – reference state c – kriti~na veli~ina – critical value r – redukovana veli~ina – reduced value

EKSPONENTI - SUPERSCRIPTS R – rezidualna veli~ina – residual quantity IG – idealan gas – ideal gas

- 227 -



[1] J. P. Joule, W. Thomson, Phil. Mag. 4 (1852) 4, 481.

[2] B.-Z. Maytal, S. W. Van Sciver, "Characterization of coolants for Joule-Thomson cryocoolers", VI me|unarodna konferencija "Cryocoolers", Zbornik radova, David Taylor Research Center, USA, 1991.

[3] R. F. Barron, "Cryogenic systems", Oxford University Press, New York, 1985.

[4] G. J. Van Wylen, R. E. Sonntag, "Fundamentals of classical thermodynamics", 2nd Ed., John Wiley & Sons, New York, 1978.

[5] B.-Z. Maytal, A. Shavit, "On the integral Joule-Thomson effect" Cryogenics 34 (1994) 1, 19-23.

[6] M. Bijedi, "Ra~unanje entalpije primjenom Soaveove modifikacije Benedict-Webb-Rubinove jednad`be stanja", Kemija u industriji 50 (2001) 5, 275-285.

[7] G. S. Soave, "A noncubic equation of state for the treatment of hydrocarbon fluids at reservoir conditions", Ind. Eng. Chem. Res. 34 (1995), 3981-3994.

[8] F. Din, "Thermodynamic functions of gases", Butterworths, London, 1960.

[9] R. C. Reid, J. M. Prausnitz, B. E. Poling, "The properties of gases and liquids", 4th Ed., McGraw-Hill inc., New York, 1987.

[10] R. D. Gunn, P. L. Chueh, J. M. Prausnitz, "Inversion temperatures of cryogenic gases and their mixtures", Cryogenics 6 (1966), 324.

[11] D. G. Miller, "Joule-Thomson inversion curve, corresponding states and simpler equation of states", J. Ind. Eng. Chem. Fund. 9 (1970) 4, 585-589.

[12] D. Vortmeyer, "The Joule-Thomson coefficient of nonpolar gas mixtures at p → 0: A theoretical interpretation of experiments (in German)", Kältetechnik 10 (1966), 383.

8. DODATAK - APPENDIX Parametri u jedna~ini (9) – Parameters in equation (9) Ψ=ρRTc/Pc

ωββ

−+

−+= 3.2

r21.6

r1c

1111T

bT

b

gdje je: b1=0.2971 b2=0.422

3

r3

2

r2

r1c 111111

−+

−+

−+=

Tc

Tc

Tcγγ

gdje je: c1=-0.02663+0.06170ω + 0.00779ω2 c2=-0.00605+0.07544ω - 0.06134ω2 c3=0.00153+0.03828ω + 0.01191ω2 δ=δχ/Τρ

3

r3

2

r2

r1c 111111

−+

−+

−+=

Te

Te

Teεε

gdje je:

e1=0.1087+0.2154ω - 0.0591ω2 e2=0.0705+0.3007ω + 0.4948ω2 e3=-0.0068+0.1858ω - 0.1157ω2 φ=0.06 βc=bZc γc=cZc

2

δc=dZc

4 εc=eZc

2

b=[15Zc-8+(2f2-2f3) ·exp(-f)]/3 c=[5Zc-8-3b-(1+f+f2) ·exp(-f)]/2 d=Zc-1-b-c-e(1+f) ·exp(-f) Zc=0.2908-0.099ω+0.04ω e=½ φ=φ/Ζχ

2

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Mainstvo 4(5), 229 –238, (2001) S. Ali: PRISTUP DEFINISANJU DINAMI^KOG MODELA...

DEFINISANJE DINAMI^KOG MODELA POKRETNE PLATFORME U REALNIM USLOVIMA

Senad Ali, dipl.in`., “BHSTEEL @ELJEZARA" Zenica, Zenica

REZIME

U ovom radu je data kinematsko-dinami~ko analiza pona~eono istresanje razli~itih materijala iz raznih v sta vagonamehani~kih parametra i uspostavljanje odgovarajuih reladinami~ki model cijelog mehanizma uz izra~unavanje dizavisno od nagiba pokretne platforme. Postavljenjem diferenporemeajne sile, te slobodnih priguenih i prinudnih Rjeavajui nehomogenu diferencijalnu jedna~inu posodgovarajuih frekvencija i perioda oscilovanja.

r

f

f

Klju~ne rije~i: pokretna platforma, dinami~ki model, pr

DYNAMICAL MODEL DEFINITPLATFORM IN REAL

Senad Ali, BSc. Mech. Eng., “BH STEEL @ELJE

SUMMARY

The analysis o kinematic-dynamic behaviour of a movablvarious materials from various types of wagons is given in determine some basic mechanic parameters and appropridynamical model o the complete mechanism is given, characteristics change with the incliation angle of the platfois given by appropriate differential equations as well thvibration of the platform mechanical system. The solution gave the expression for related frequencies and periods of

Key words: movable platform, dynamical model, forced

1. UVOD Pokretne platforme nale su primjenu na primjeru transportnih sredstava za rasute materijale zbog brzine i jednostavnosti istresanja. Ovdje je razmatran problem platforme koja ima ograni~eno rotaciono kretanje. Odraz dinami~ke neravnomjernosti rada pokretne platforme su vibracije ~iji intenzitet i karakter do sada nije ispitivan. Proces optereenja ide sljedeim redom. Vagoni se dovoze i postavljaju na pokretnu platformu koja se oko nepokretnog oslonca "A", (slika 1.), okree α = 0° - 60°. Pogonski mehanizam platforme ima dva paralelna ~eli~na uèta koji je sinhrono diù. Sila u ~eli~nom uètu ima svoju maksimalnu vrijednost pri nagibu platforme α ≈ 0°, a minimalnu pri nagibu platforme α=60°. Dosadanja iskustva pokazuju da se skoro svi rasuti materijali istresaju pri nagibu platforme α ≈ 22° - 35°.

1. IN Movabtranspoand tconsidlimitedinconsthe vibbeen followinmovabthe imdrivingare lifthas itsat α≈0α=60°almostplatform

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PRETHODNO SAOP[TENJE

anje pokretne platforme namijenjene za . Cilj ove analize je definisanje osnovnih cija njihove promjene. Tako|er, dat je nami~kih karakteristika koje se mijenjaju cijalne jedna~ine dat je karakter promjene oscilacija mehani~kog sistema platforme. tavljene su relacije za izra~unavanje

f

inudne oscilacije.

ION OF MOVABLE CONDITIONS

ZARA” Zenica, Zenica

e platfthis pate epalong rm. Ae anao novibrati

vibrat

TRO

le platfrt meahe simers the rotatioistencyrationsanalyseg steple platfmovab meched syn maxim°, and. The all th inclin

PRELIMINARY NOTES

orm aimed for frontal discharge of aper. The point of the analysis is to ressions of their variation. Also the with the expressions for dynamic varying character of exitation force lysis of free damped and forced n-homogeneous differential equation ons definition.

ions.

DUCTION

orms have found their application with the ns for loose materials, due to their speed plicity of their unloading. The paper problem of the platform which has a nal motion. The reflection of dynamic of the movable platform’s operation are , whose intensity and character has not d before. The loading process has the s. The wagons are driven and set to the orm, which rotates for α = 0°-60° around le support "A", (Figure 1.). The platform’s anism has two parallel steel ropes which chronously. The force in the steel rope um value when the platform is inclined

its minimum value when it is inclined at experiences so far have showed that e loose materials are unloaded at the ation angle of α ≈ 22°-35°.


Sistem pokretne platforme sa vagonom i teretom je elasti~an mehani~ki sistem a vu~na sila u ~eli~nom uètu se mijenja zavisno od poloàja pokretne platforme i stalno po istoj zakonitosti. Brzina dizanja i sputanja pokretne platforme je mala, jer proces dizanja i istresanja materijala iz vagona traje t ≈ 2 [min]. Proces dizanja obi~no traje t ≈ 68 [sec], a proces sputanja t ≈ 52 [sec]. Ovo vrijeme varira i zavisi od vie faktora. Da bi se problem egzaktno rjeavao potrebno je cijeli mehanizam, pogonsko vitlo, prenos ~eli~nim uàdima sa donjom pokretnom nestacionarnom i gornjom nepokretnom kotura~om i platformu sa teretom posmatrati u dinami~kim uslovima. Treba analizirati kinematsku emu mehanizma i za nju odrediti sve potrebne parametre kretanja. Cilj ovog rada je da se kroz dinami~ku analizu definiu osnovni parametri koji mogu posluìti kod rekonstrukcije mehani~kih platformi velikih gabarita i njihovom prilago|avanju hidrauli~nom pogonu.

The system of the movable platform with wagon and load is an elastic mechanical system and the tensile force in the steel rope changes depending on the movable platform’s position by the same law. The lifting and lowering speed of the movable platform is low because the process of the material lift and unload from the wagon lasts for t ≈ 2 [min]. The process of lifting usually lasts for t ≈ 68 [sec], and the process of lowering for t ≈ 52 [sec]. This time varies and it depends on several factors. In order for the problem to be solved with exactness, it is necessary to consider the whole mechanism, the driving winch, the transport with the steel ropes with lower movable non- stationary and upper immovable pulley block, as well as the platform with the load, in the dynamic conditions. It is also necessary to analyse the kinematic pattern of the mechanism, and to establish all its motion parameters needed. The aim of this paper is to define the basic parameters through the dynamic analysis, which can be used when reconstructing mechanical platforms of huge overall sizes, and when they are adapted to the hydraulic drive.

2. KINEMATSKA ANALIZA POKRETNE PLATFORME

U cilju definisanja ponaanja platforme za istovar vagona u uslovima nestacionarnog stanja, izme|u ostalog, je potrebno odrediti zakon promjene kinematskih karakteristika pokretnog oslonca B u odnosu na nepokretni oslonac C. Ovdje e se posmatrati brzina i ubrzanje oslone ta~ke “B” (slika 1), tj. donjeg sklopa kotura~a koje u svom radu se pribliàvaju za neku vrijednost (y) gornjem stacionarnom sklopu kotura~a. U po~etnom stanju je ovaj razmak najvei da bi u poloàju platforme α = 60° bio najmanji. Prema kosinusnoj teoremi koritenoj za rjeavanje trougla ∆ ABC dobije se zakon promjene uglova α, β i γ u funkciji pomaka donje kotura~e prema gornjoj. Duìna AB = b na osnovu geometrijskih veli~ina je uvijek konstantna (b = 5,1125[m]), dok je l = (do – y) stalno promjenjiva veli~ina. Koristei izraze kosinusne teoreme dobije se:

2. KINEMATIC ANAYISIS OF THE MOVABLE PLATFORM

In order to define the behaviour of the platform for wagon unloads in the non-stationary conditions, it is necessary, among other things, to determine the law of change in kinematic characteristics of the movable support B in relation to the immovable support C. The speed and the acceleration of the point “B”, i.e. of the lower fit of the pulley blocks will be observed here (Figure 1), which, during their operation, advance the upper stationary fit of the pulley blocks for a specific value (y). This gap is the widest at the beginning and the narrowest in the platform’s position α = 60°. According to the cosine theorem, used to solve the triangle ∆ ABC, the pattern of the angle α, β and γ change is determined, in the function of the feed of the lower pulley block towards the upper pulley block. The length AB = b, according to the geometrical sizes, is always constant (b = 5,1125[m]), whereas l = (do – y) is variable. By using the cosine theorem expressions, the following is established:

a2 = b2 + l2 – 2bl cosα1 , ( )

( )ydbkyd

arco

o

−⋅−−

=2

cos22

1α

b2 = a2 + l2 – 2al cosβ1 , ( )

( )ydakyd

arco

o

−⋅+−

=2

cos22

1β

l2 = a2 + b2 – 2ab cosγ1 , ( )

ab2ydn

cosarc2

o2

1−−

=γ

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gdje su (where) k2 = a2 – b2 , n2 = a2 + b2 , l = do – y , 0 ≤ do – y ≤ do. Apsolutna brzina ta~ke “B” pokretne platforme je:

1

..

1 γγ bABvB == (1)

The absolute speed of the point “B” of the movable platform is:

1

..

1 γγ bABvB == (1)

Radijalna i cirkularna komponenta ove brzine su:

11

.

1B

.

r sinbsinvvyv αγ=α=== (2)

( ) 11

.

1B

.

1oc cosbcosvydv αγ=α=β−= (3)

Iz jedna~ina za vr i vc uz koritenja izraza za vB i α dobijaju se ugaone brzine:

The radial and the circular components of this speed are:

111Br sinbsinvvyv αγα && ==== (2)

( ) 111B1oc cosbcosvydv αγαβ && ==−= (3)

From the equations for vr and vc, by using the expressions for vB and α1, the angular speeds can be determined:

( )( ) ( )[ ]

.

22221

.

4

2y

kydydb

yd

oo

o

−−−−

−⋅=γ (4)

( )[ ]( ) ( ) ( )[ ]

.

2222

22

1

.

4y

kydydbyd

kyd

ooo

o

−−−−−

−−=β (5)

Diferenciranjem izraza za ugaone brzine kao slo`enih funkcija od (y) pri ~emu je y = y(t) dobijaju se ugaona ubrzanja:

By differentiating the expressions for angular speed as complex functions of (y), where y = y (t), the angular accelerations are established:

( )[ ]( ) ( )[ ]

( )( ) ( )[ ]

ykydydb

ydy

kydydb

kyd

oo

o

oo

o &&22222

2

322224

44

14

2

4

2

−−−−

−⋅+

−−−−

−−=

...γ (6)

( ) ( )[ ]( ) ( ) ( )[ ]

( )[ ]( ) ( ) ( )[ ]

ykydydbyd

kydy

kydydbyd

kydkydb

ooo

o

ooo

oo &&22222

222

322222

322222

1

44

8

−−−−−

−−+

−−−−−

−−+−=

...β (7)

β

α

γ

αvc

B

1

Bv

A

b 1

vr

1

1

l

a

l = d - yb = const.a = const.

o

D

C

α = 0o; l=do α = 60o ; l =do-ymax 0≤y≤ymax

Slika 1. Kinematska ema sa apsolutnom brzinom ta~ke “B” Figure 1. Kinematic chart with the absolute speed of the point “B”

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3. TEORIJSKA ANALIZA OSCILACIJA DINAMI^KOG MODELA

Model koji je dat na Slici 2., uzima u obzir da je pokretna platforma sa reetkastom konstrukcijom kruta. Ovo se usvaja jer je krutost platforme neuporedivo vea od krutosti pogonskog vitla. Sa ovom pretpostavkom mo`e se mehanizam pokretne platforme smatrati modelom sa jednim stepenom slobode kretanja – pomjeranjem (y) i u optem slu~aju sa promjenjivom redukovanom masom i krutou. Pomjeranje (y) je ustvari smanjenje maksimalnog rastojanja (do) tj. to je rastojanje izme|u gornje nepokretne kotura~e i donje pokretne kotura~e preko kojih je namotano ~eli~no u`e. Kada je nagib platforme α = 0° rastojanje je najvee (do), a sa nagibom to rastojanje se smanjuje (do – y) i ima najmanju vrijednost pri nagibu α = 60°. Vrijednost (y) se mijenja i pri nagibu platforme α ≅ 0° je ymin, a pri nagibu α = 60° ima maksimalnu vrijednost (ymax), (slika 1).

3. THEORETICAL ANALYSIS OF THE DYNAMIC MODEL OSCILLATIONS

The model, presented in the Figure 2, takes into consideration that the movable platform with grid construction is rigid. This is adopted because the rigidity of the platform is far greater that the rigidity of the driving winch. Under this supposition, the movable platform mechanism can be regarded as a model with a degree of motion freedom – by displacement (y), and in general with a variable reduced mass and rigidity. The displacement (y) is in fact the reduction of the maximum distance (do), i.e. it is the distance between the upper immovable pulley block and the lower movable pulley block over which the steel rope is wound. When the inclination of the platform is α ≅ 0°, the distance is the biggest (do). The distance decreases with the inclination (do – y) and is the lowest at the inclination angle α = 60°. The value (y) changes and when the inclination of the platform is α ≅ 0°, then it is ymin, when the inclination α = 60°, it reaches its maximum value (ymax), (Figure 1).

α

.

B

A

c

β = 23,95735368°

FBb

C

D

a)

.

A

BM t

b)

m (y)r F (y)B

b M

c (y)

m

C

Slika 2. Dinami~ki model pokretne platforme sa promjenjivom masom i krutou Figure 2. Dynamic model o the movable platform with variable mass and rigidity f

U spoljanja optereenja spadaju aktivne sile ili momenti stvoreni elektromotorom. Za pogonski mehanizam pokretne platforme ema rasporeda momenata izgleda kao na slici 3. Za rjeavanje zadataka dimanike podesno je da se eme mehanizama predstave u vidu odvojenih elemenata, spojenih me|usobno elasti~nim elementima. Za stvarni mehanizam pokretne platforme, prema slici 3., pogonsko vitlo ima mase m1, m2, m3, m4 i m5, momente inercije I1, I2, I3, I4 i I5, prenosne odnose i1, i2, i3, i4 i i5.

The external loads are active forces and moments produced with electric motor. The moment chart for the movable platform driving mechanism is presented in the Figure 3. When solving problems in dynamics, it is convenient to present the mechanism charts as separate elements, coupled with elastic elements. For the real mechanism of the movable platform, according to the Figure 3, the driving winch has the masses m1, m2, m3, m4 and m5, the moments of inertia I1, I2, I3, I4 and I5, the transmission ratios i1, i2, i3, i4 and i5.

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Drugi dio mehanizma je pokretna platforma sa teretom koja ima moment inercije IPA + IVA, svoje mase mP + mVt i prenosni odnos na osu pogonskog bubnja i5. Moment inercije IPVC e biti:

The second part of the mechanism is the movable platform with the load, with its moment of inertia IPA + IVA, its mass mP + mVt, and its transmission ratio to the driving barrel centre line i5. The moment of inertia IPVC will be:

IPVC = I1 i12 + I2 i22 + I3 i32 + I4 i42 + I5 i52 (8)

gdje je: IPVC – redukovani moment inercije masa svih elemenata pogonskog vitla, I1, I2, I3, I4 i I5 – momenti inercije masa elemenata po stvarnoj emi pogonskog vitla, i1, i2, i3, i4 i i5 – odgovarajui prenosni odnosi .

where: IPVC – is a reduced moment of inertia of masses of all the driving winch elements I1, I2, I3, I4 and I5 – moments of inertia of the masses of elements according to the real chart of the driving winch, i1, i2, i3, i4 and i5 – adequate transmission ratios .

M

I2i2 η m

2SM3m

3c

3

m

2

3SM

η3i 3

44SM

4

ηi4 4

c

2c

cηi1 1

2I1SM

11m

II

.

VAPAI I

1

PVC

V

m5

mr

I

4

I 5

IIV

III

ic5

oc

= d

- y

5

m2r

1t

II

Slika 3. [ema cijelog mehanizma pokretne platforme sa redukcijom masa, momenata inercije i krutosti

Figure 3. The chart of the who e movable platform mechanism with the reduction of masses, moments of inertia and rigidity

l,

Redukovani dinami~ki moment inercije pokretne platforme sa teretom se ra~una na sljedei na~in:

IPA + IVTA = IukA = mukA⋅R2 (9)

IPA + IVA = IukA = mukA⋅R2 (10) gdje je: mukA – ukupna masa platforme, vagona sa i bez tereta, R – polupre~nik rotacije ove mase, IPA – dinami~ki moment inercije pokretne platforme, IVA – dinami~ki moment vagona sa teretom. Ukupna masa sistema u dva krajnja radna polo`aja α ≈ 0° i α = 60° je: mukA = mp + mvt , mukA = mp + mv

gdje su: mp – ukupna masa pokretne platforme zajedno sa svim prateim dijelovima, mvt, mv – ukupna masa vagona sa i bez tereta.

The reduced dynamic moment of inertia of the loaded movable platform is calculated in the following manner:

IPA + IVTA = IukA = mukA⋅R2 (9)

IPA + IVA = IukA = mukA⋅R2 (10)

where: mukA – is the overall platform mass, wagon with and without load, R – the radius of the rotation of this mass, IPA – the movable platform dynamic moment of inertia, IVA – the dynamic moment of the wagon without load, IVTA – the dynamic moment of the wagon with load.

The overall mass of the system in the two final operation positions α ≈ 0° and α = 60° is: mukA = mp + mvt , mukA = mp + mv , where: mp – is the movable platform overall mass, along

with all the accompanying parts, mvt, mv – the overall wagon mass with and without load.

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Masa svih pokretnih dijelova redukuje se na osu pogonskog bubnja. Redukcija se vri na bazi jednakosti kineti~ke i potencijalne energije stvarnog mehani~kog sistema koji se redukuje, (slika 2.a), i energije mehani~kog sistema na koji se redukuje, (slika 2.b). Izjedna~avanjem kineti~ke energije obrtanja ~lanova 1 i 2 sa kineti~kom energijom redukovane mase (mr), koja se kree pribli`no translatorno, kako se pomjera oslonac “B” dobie se:

The mass of all the movable parts is reduced on the driving barrel centre line. The reduction is performed on the basis of the equality of kinetic energy of the real mechanic system being reduced (Figure 2.a), and the energy of the mechanical system on which it is reduced (Figure 2.b). By equalising the kinetic energy of revolution of the members 1 and 2 with the kinetic energy of the reduced mass (mr), which has approximately translatory motion, according to the motion of the support “B”, we get the following:

( )2.

r2

1

.

PVC2

1

.

VAPA ym21III

21

=

β+γ+ (11)

Ako se u ovu jedna~inu uvrste jedna~ine za dobie se: 1 i βγ &&

If we insert into (11) the equations for we

get: 1 i βγ &&

2

1

.

2.

PVC21

.

2.

VAPAr

y

I

y

IIβ+γ

+=m ,

( )2o

12

12

PVC

122

VAPAr yd

cossin

Isinb

IIm

−α

⋅α

+α

+= (12)

Koristei trigonometrijske relacije i izraz cosinusne teoreme za (α1) i uvrtavanjem u jedna~inu (12) dobie se:

By using trigonometry relations and cosine theorem for (α1) and by inserting it in the equation (12) we get:

( )21

2

12

122 yd

lIb

IImo

PVCVAPAr

−

−⋅+

+=

)sin(sinsin

ααα

( ) ( )( ) ( )[ ] ( )

( )( ) ( )[ ]

−−−−−

−

−+

−−−−

+−= l

kydydb

ydbyd

I

kydydb

IIydmoo

o

o

PVC

oo

VAPAor 22222

22

222222

2

4

4

4

4 (13)

pri ~emu je 0 ≤ y ≤ ymax = h Iz izraza (12) se vidi da je mr = mr (y), i da se mijenja u intervalu:

It can be seen from the expression (12) that mr = mr (y), in changes in the interval:

( )( ) ( ) ( )

( ) ( )( ) ( )[ ] ( )

( )( ) ( )[ ] 0

0

60

22222

22

222222

2

0

2220

20

2

20

2

22222

2

4

4

4

4

4

4

4

4

=

≅

−−−−−

−

−+

−−−−

+⋅−⋅≤

≤≤

−

−−+

−−

+⋅

α

α

lkydydb

ydbyd

I

kydydb

IIyd

ymlkddb

dbdI

kddb

IId

oo

o

o

PVC

oo

VAPAo

ro

PVC

oo

VAPAo

(14)

Pod krutou mehani~kog sistema ili pojedinog njegovog elementa podrazumijeva se odnos optereenja i deformacije koju je izazvalo to optereenje. Krutost moè biti linearna (sila pri linearnoj deformaciji) i ugaona (moment sile pri ugaonoj deformaciji). Na slici 3. date su krutosti elemenata mehani~kog sistema pokretne platforme. Sa slike je vidljivo da pogonsko vitlo mehani~kog sistema ima obrtne mase i za njega se odre|uje ugaona krutost. Mehani~ki sistem tako|e sadrì i prijenos uàdima izme|u donje pokretne i gornje nepokretne kotura~e i za ovaj dio se mora odrediti linearna krutost ~eli~nih uàdi.

The rigidity of a mechanical system or one of its elements represents the relationship between the load and the deformity caused by that load. Rigidity can be linear (force at linear deformity) and angular (the moment of force at angular deformity). The Figure 3 presents the rigidity of the elements of the movable platform mechanical system. One can see in the figure that the driving winch of the mechanical system has the rotary mass, and the angular rigidity can be defined for it. The mechanical system also has the transmission by ropes between the lower movable and the upper immovable pulley block, and the linear rigidity of the steel ropes must be determined.

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Dakle, mehani~ki sistem ima linearnu i ugaonu krutost, tj, pribli`no translatorno i obrtno kretanje masa, tako da se na osnovu njih odre|uje ekvivalentna krutost koja moè biti pretpostavljena kao linearna ili ugaona. Ugaona krutost pogonskog vitla se odre|uje kao odnos redukovanog momenta uvijanja M i ugaone deformacije ϕ, tj.

The mechanical system therefore has both the linear and the angular rigidity, i.e. approximate translatory and rotary motion of masses, on the basis of which the equivalent rigidity, which can be presupposed as linear or angular, can be defined. The angular rigidity of the driving winch is defined as the relationship of the reduced moment of torsion M and the angular deformity ϕ, i.e.:

++++

====

45

54

4

44

3

34

2

24

1

14

1

3232dl

dl

dl

dl

dl

G

dl

GlGIMc P ππ

ϕ (15)

Linearna krutost ~eli~nih uàdi preko kojih se donja pokretna kotura~a kree pribli`no translatorno u zavisnosti je od promjene "y" (0 ≤ y ≤ h, l=do–y). Za nagib pokretne platforme α ≅ 0° (l=do), a za nagib platforme α = 60° (l=do–y), pa e biti:

lEA

EAlF

FlF

fFc

B

BBB ==∆

==2 (16)

Ekvivalentna krutost mehani~kog sistema pokretne platforme cr= cr(y) se mijenja u intervalu:

The linear rigidity of the steel ropes, over which the lower movable pulley block moves approximately translatory, depends on the change "y" (0 ≤ y ≤ h, l=do–y). For the inclination of the movable platform α ≅ 0° (l=do), and for the inclination of the platform α = 60° (l=do–y), and we have:

lEA

EAlF

FlF

fFc

B

BBB ==∆

==2 (16)

The equivalent rigidity of the movable platform mechanical system cr= cr(y) changes in the interval:

( )oo ccR

ccycccR

ccr

60122

21

0122

21

=≅

+⋅⋅

≤≤

+⋅⋅

αα

(17)

4. DIFERENCIJALNA JEDNAÎNA KRETANJA MEHANIZMA POKRETNE PLATFORME

Diferencijalna jedna~ina kretanja se postavlja primjenom Lagrange–ove jedna~ine druge vrste za mehani~ki sistem na koji djeluju konzervativne sile koje su u funkciji pomaka (y).

nkk QQyy

Ek

y

Ekdtd

+=∂

∂+

∂∂

−

∂

∂..

φ (18)

Poto je generalisana konzervativna sila yEpk

∂∂

−=

)( yFBp =

Q ,

a generalisana poremeajna sila u

sklopu ~eli~ne uàdi, sila koja djeluje na ta~ku “B”, moè se jedna~ina (18) pisati u obliku:

Q

( )yFyEp

yyEk

y

Ekdtd

B.. =∂

∂+

∂

∂+

∂∂

−

∂

∂ φ (18)

Izrazi za Ek i Ep koji figuriu u gornjem obrascu su:

( ) 2

21 yymEk r &= , ( ) 2

21 yycEp r ⋅= , 2

21 yb&=φ .

4. THE DIFFERENTIAL EQUATION OF THE MOVABLE PLATFORM MOTION OF MECHANISM

The differential equation is set by applying Lagrange’s secondary equation for the mechanical system which is, apart the conservative forces, that is in the function of the feed (y).

nkk QQyy

Ek

y

Ekdtd

+=∂

∂+

∂∂

−

∂

∂..

φ (18)

Since the generalised conservative force

yEp

Qk∂

∂−=

)( yFQ Bp =

, and the generalised deformity force

the equation (18) can be written in

the following form:

( )yFyEp

yyEk

y

Ekdtd

B.. =∂

∂+

∂

∂+

∂∂

−

∂

∂ φ (19)

The expressions for Ek and Ep from the above expression are:

( ) 2

21 yymEk r &= , ( ) 2

21 yycEp r ⋅= , 2

21 yb&=φ .

Nalaènjem potrebnih izvoda i uvrtavanjem u jedna~inu (19) dobije se:

By finding the necessary derivative and by inserting it into the equation (19) we get:

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( ) ( ) ( )yFybyycydyydc

21y

dy)y(dm

21y)y(my)y(m Br

2r2rrr =+++−+ &&&&&&& (20)

Dobijena diferencijalna jedna~ina je nelinearna, nehomogena ~ije je rjeenje u zatvorenom obliku vrlo komplikovano. Zato se ova jedna~ina mora integrisati numeri~ki. Jedna~ina (20) se moè pojednostaviti tj. svesti na linearnu nehomogenu diferencijalnu jedna~inu koja se moè lahko integrisati za dati trenutak vremena. Na osnovu prethodnih jedna~ina mogue je izra~unati FB(y), mr(y) i cr(y), njihove konkretne vrijednosti i to uvrstiti u diferencijalnu jedna~inu. Sila FB(y), se moè razviti u Fourier-ov red oblika:

The above differential equation is non-linear, non-homogeneous, whose solution in the closed form is very complicated. That is why this equation has to be numerically integrated. The equation (20) can be simplified, i.e. reduced to a linear differential equation that can be easily integrated for a specific moment of time. On the basis of the previous equations, it is possible to calculate FB(y), mr(y) and cr(y), their concrete values and insert that into the differential equation. The force FB(y), can be developed into the Fourier’s series of forms:

( ) ( )∑∞

=

++=1n

nnBoB tnsinBtncosAFtF ΩΩ , (21)

s obzirom da je linijska veli~ina y = y(t) promjenljiva, to su FBo, An i Bn promjenljive veli~ine. FBo je srednja vrijednost sile FB(t) , koja se uz koeficijente An i Bn odre|uje:

Considering that a linear value y=y(t) is variable, thus FBo, An i Bn are varialble too. FBo is the mean value of the force FB(t) , which is with the coefficients An and Bn defined as:

( )∫=Ω

Ω

T

0BBo dttF

T1F , ( ) ( )∫∫ ==

ΩΩ

ΩΩΩΩ

T

0Bn

T

0Bn dtnsintF

T2B,dtncostF

T2A . (22)

Kako je An = Cn ⋅ cosρn ; Bn = Cn ⋅ sinρn ;

2n

2nn BAC += ;

n

nn A

Btg =ρ , moè se

pisati:

( ) ( )∑∞

=

−+=1n

nnBoB tncosCFtF ρΩ .

Na osnovu prethodnog dobie se diferencijalna jedna~ina u obliku :

( )( )ymyFyy2y

r

B2 =++ ωδ&&& (23)

( )( )

( )( )ymyc,

ymbym2

r

r2

r

r =+

= ωδ&

Rjeenje ove jedna~ine moè se pretpostaviti u obliku zbira homogenog i partikularnog integrala:

y = yh + yp , (24) gdje su: yh – zakon slobodnih priguenih oscilacija, yp – zakon prinudnih oscilacija.

Since An = Cn ⋅ cosρn ; Bn = Cn ⋅ sinρn ;

2n

2nn BAC += ;

n

nn A

Btg =ρ , it can be

written that:

( ) ( )∑∞

=

−+=1n

nnBoB tncosCFtF ρΩ .

According to the above, the result is the differential equation in the following form:

( )( )ymyFyy2y

r

B2 =++ ωδ&&& (23)

( )( )

( )( )ymyc,

ymbym2

r

r2

r

r =+

= ωδ&

.

The solution to this equation can be set in the form of the sum of the homogeneous and the particular integral:

y = yh + yp , (24) with: yh – the law of free damped oscillations, yp – the law of forced oscillations.

Rjeenje homogenog dijela diferencijalne jedna~ine (23) se traì u obliku:

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yh = e-δt [C1cospt + C2sinpt] , (25)

gdje su: C1 i C2 – integracione konstante koje se odre|uju iz po~etnih uslova kretanja.

Prije po~etka dizanja pokretne platforme sa vagonom i teretom vrijede po~etni uslovi

( ) 00t yy == , , (26) ( ) 00t yy && ==

na osnovu kojih se iz jedna~ine (24) dobiju integracione konstante:

pyyC;yC 00

201δ+

==&

, (27)

Ako su konstante C1 = A sinβ i C2 = A cosβ i kad se uvrsti u (27) dobije se:

( )2

20o2

022

21 p

yyyCCA δ++=+=

&, (28)

pyyy

tgarcCCtgarc

0

0o

1

2 δβ

+==

&.

Tada je homogeni integral:

( βδ −⋅= − ptcosAey th ) , (29)

gdje je: e-δtA– amplituda oscilovanja izraèna u funkciji vremena, β – fazni ugao Partikularni inegral iznosi:

( ) ( ) ( )∑∞

=

−+=1n

nnrr

Bop tncosC

ym1

ymF

y ρΩ (30)

Zakon kretanja, koji zadovoljava po~etne uslove moè se napisati u obliku: The solution of the homogeneous part of the differential equation (23) can be found in the form:

yh = e-

δt [C1cospt + C2sinpt] , (25)

where: C1and C2 – are the integration constants defined from the starting conditions of motion.

Before lifting the movable platform with the wagon and load, the following starting conditions are valid:

( ) 00t yy == , , (26) ( ) 00t yy && ==

on the basis of which from the equation (24) we can get the integration constants:

pyy

C;yC 00201

δ+==&

, (27)

If the constants are C1 = A sinβ and C2 = A cosβ, when they are inserted into (27) we get:

( )2

20o2

022

21 p

yyyCCA δ++=+=

&, (28)

pyyy

tgarcCCtgarc

0

0o

1

2 δβ

+==

&.

The homogeneous integral is then:

( βδ −⋅= − ptcosAey th ) , (29)

where: e-δtA– the amplitude of oscillation expressed in the function of time, β – the phase angle The particular integral is:

( ) ( ) ( )∑∞

=

−+=1n

nnrr

Bop tncosC

ym1

ymF

y ρΩ (30)

The law of motion, which satisfies the starting conditions, can be written in the following form:

( ) ( ) ( ) (∑∞

=

− −++−⋅=1n

nnrr

Bot tncosCym1

ymF

ptcosAey ρΩβδ ) . (31)

Prividni period priguenja od slobodnih priguenih oscilacija i period oscilovanja od poremeajne sile iznose:

22p2

p2T

δω

ππ

−== ,

Ωπ

Ω2

=T , (32)

gdje je: 22p δ−ω= – kru`na frekvencija slobodnih

priguenih oscilacija, Ω – kru`na frekvencija promjene generalisane poremeajne sile.

The virtual damping period from free damped oscillations and the oscillation period from the deformation force are:

22p2

p2T

δω

ππ

−== ,

Ωπ

Ω2

=T , (32)

where: 22p δ−ω= – the rotary frequency of the free

damped oscillations, Ω – the rotary frequency of the change of the generalised deformity force.

5. ZAKLJUÂK

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Na osnovu definisanih polaznih razmatranja i uz izvrenu aproksimaciju, uo~ava se da se za ovakve i sli~ne mehanizme mogu postaviti odgovarajue relacije i zakonitosti promjene dinami~kih veli~ina. Vidljivo je da se promjenom rastojanja “l” mjenjaju odgovarajui dinami~ki parametri. To su redukovana masa mehani~kog sistema, ekvivalentna krutost, veli~ina poremeajne sile, itd. Ove veli~ine daju promjenu ostalih dinami~kih veli~ina (frekvencije i periodi oscilovanja). Kona~no rjeenje nehomogene diferencijalne jedna~ine je matematski, a ne inènjerski problem i on moè biti tematika nekog drugog rada. Matematska analiza daje odgovarajui nivo aproksimacije ovakvih i sli~nih inènjerskih problema. Ta~nost matematske razrade bi bilo mogue provjeriti odgovarajuim eksperimentalnim mjerenjima to, opet, moè biti tematika nekog drugog rada. Sprovedena dinami~ka analiza je definisala iznalaènje osnovnih parametara i dala smjernice za dalja istraìvanja, to bi trebalo znatno da olaka rad projektantima koji se bave ovom problematikom.

5. CONCLULUSION

On the basis of the defined starting considerations, and with the performed approximation, it can be noticed that adequate relations and laws of the change in dynamic values can be defined for these and similar mechanisms. It is obvious that the change in the distance “l” causes the change in certain dynamic parameters. These are the reduced mass of the mechanic system, equivalent rigidity, the deformity force value, etc. These values cause the change in other dynamic values (frequency and the oscillation periods). Finally, the solution of the non-homogeneous differential equation is a mathematical, not an engineering problem, which can be a topic of some other paper. Mathematical analysis gives a certain level of approximation of these and similar engineering problems. The precision of the mathematical development of the problem could be checked by adequate experimental measurements, which, again, can be a topic of some other paper. The conducted dynamic analysis has defined the ways of finding the basic parameters, and it has given the directions for further research, which should considerably ease the work for the engineers engaged in these issues.


[1] Komarov M.S.: Dinamika mehanizama i maina, Mainostroenie, Moskva, 1969.,

[2] Vukojevi D.: Dinamika maina I i II, Mainski fakultet, Zenica, 1996.,

[3] Vukojevi D.: Teorija oscilacija, Mainski fakultet, Zenica, 1997.,

[4] Vukojevi D.: Dinamika, Mainski fakultet, Zenica, 1990.,

[5] Timoenko S. P.: Vibration problems in engineering, New York - London, 1955.

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OSNOVNI KONCEPTI ISO 10303 (STEP) STANDARDA ZA RAZMJENU PODATAKA IZME\U CAD SISTEMA

Enes Pivi, dipl. in`. ma., Mainski fakultet u Zenici, Fakultetska 1, Zenica, Bosna i Hercegovina REZIME

Razmjena podataka izme|u CAD sistema je dugo godina cilj mnogih inicijativa, analiza, istraìva~kih radova, saradnje i projekata. Veliki napor je uloèn na polju povezivanja dva razli~ita CAD sistema. Ovaj rad prezentuje osnovne koncepte, strukturu i metodologiju razvoja ISO 10303 (STEP) standarda za razmjenu podataka izme|u CAD sistema. S ciljem pruànja potpunije slike o cijelom procesu razmjene podataka izme|u CAD sistema kao i isticanja va`nosti STEP standarda, u radu je tako|e dat kratak pregled istorijskog razvoja razmjene podataka izme|u CAD sistema. Pored osnovnih koncepata STEP standarda u radu je dat i kratak opis ST-razvojne okoline – softverskih alata za rad na EXPRESS informacionom modelu.

Klju~ne rije~i: STEP, ISO 10303, PDES, CAD razmjena podataka, EXPRESS

BASIC CONCEPTS OF ISO 10303 (STEP) STANDARD FOR DATA EXCHANGE BETWEEN CAD SYSTEMS

Enes Pivi, B.Sc., Mech. Eng., Faculty of Mechanical Engineering in Zenica, Fakultetska 1, 72000 Zenica, Bosnia and Herzegovina

SUMMARY

CAD data exchange has been the goal of many initiatives, analyses, research works, (collaborations) projects nad of a great deal of team work for many years. A lot of effort has been input in linking two dissimilar CAD Systems to each other. This paper presents basic concepts, structure and development methodology of ISO 10303 (STEP) standard for data exchange between CAD Systems. In order to give a more complete picture of the whole CAD data exchange process and to emphasize the importance of the STEP standard, the paper also presents an overview of historical development of the CAD data exchange. In addition to the basic concepts of the STEP standard, this paper gives an overview of the ST-Developer – a software tools for working with the EXPRESS information model.

Key Words: STEP, ISO 10303, PDES, CAD Data Exchange, EXPRESS

1. UVOD U posljednjih 30 godina razvoj CAD sistema je proao kroz najmanje ~etiri glavne faze razvoja u smislu razmjene podataka. Faze razvoja su slijedee:

• razmjena grafi~kih podataka, • razmjena podataka inènjerskih crteà, • razmjena geometrijskih podataka i • razmjena podataka proizvodnog modela

Navedene faze razvoja se mogu predstaviti grafi~ki kao to je to prikazano na slici 1.:

1. INTRODUCTION In the past 30 years the development of CAD Systems has gone through at least four main phases regarding data exchange. These phases are as follows:

• graphical data exchange, • engineering drawing data exchange, • geometry data exchange and • product model data exchange.

The above-mentioned phases can be graphically presented as shown on the Figure 1.:

PREGLEDNI RAD

SUBJECT REVIEW

- 240 -

Slika 1. Faze razmjene plodataka izme|u CAD sistema Figure 1. Phases of the CAD data exchange

Ove faze razvoja je danas mogue shvatiti kao razvoj sistema za kompjutersku grafiku, sistema za crtenje i sistema za geometrijsko modeliranje. Dananja istraìvanja i razvojni projekti su usmjereni na sisteme za modeliranje proizvoda [2] [p195]. Izazov modeliranja proizvoda je u tome da se obezbjedi kompletna metodologija za cijeli ìvotni ciklus proizvoda, obezbje|ujui koherentno procesiranje podataka pomou svih svih kompjuterskih sistema koji se koriste u ìvotnom ciklusu proizvoda. Pristup za postizanje ovog cilja je zasnovan na definiciji koherentnih modela proizvoda. Ovo je tako|e i glavni cilj STEP standarda (Standard za razmjenu podataka proizvoda) i moè se grafi~ki predstaviti na sljedei na~in:

Today, these phases can be regarded as development of Computer Graphics Systems, Draughting Systems and Geometric Modeling Systems. Today research and development projects are focused on Product Modeling Systems [2] [p195]. The challenge of product modeling is in providing a complete methodology for the whole product life cycle, enabling a coherent product data processing by all computer systems which are being used in the product life cycle. The approach for achieving this goal is based on the definition of a coherent product model. This is also the main goal of the STEP (Standard for Exchange of Product Data) development and can be graphically presented as follows:

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Slika 2. STEP interfejs izme|u CAx komponenata Figure 2. STEP interface between CAx components

2. ISTORIJSKI RAZVOJ RAZMJENE PODATAKA IZME\U CAD SISTEMA Prvi zna~ajniji rad na razmjeni podataka je bio 1979 godine uspostavljanje IGES-a (Inicijalne specifikacije za razmjenu grafike) podrànog od strane ameri~kog nacionalnog Odbora za standardizaciju (prihvaen od strane ANSI standarda 1981). Ovaj standard su razvili, uglavnom, ameri~ki proizvo|a~i CAD sistema, i primjenjen je kao format za transfer ASCII fajla koji se mogao razmjenjivati izme|u bilo koja dva CAD sistema. Prve implementacije IGES prevodilaca, koje su razvili proizvo|a~i CAD, sistema su bile manje pouzdane – dijelom zbog neodre|enosti u specifikaciji a dijelom jer su neki proizvo|a~i CAD sistema implementirali samo dio standarda. Ovakve potekoe su natjerale francusku kompaniju Aerospatiale da razvije vlastiti standard SET (Standard d’Echange et de Transfert), koji je kasnije (1985. godine) prihvaen od strane francuskog nacionalnog tijela za standardizaciju (AFNOR) kao stadard i od tada postao iroko primjenljiv u evropskoj avio industriji. SET standard koristi sli~an model podataka kao i IGES, ali u mnogo kompaktnijem formatu.

2. THE HISTORICAL DEVELOPMENT OF CAD DATA EXCHANGE The first significant work in data exchange was the establishment in 1979 of an Initial Graphics Exchange Specification (IGES), supported by the US National Bureau of Standards (and eventually adopted by ANSI in 1981). This standard was developed mainly by major US CAD vendors, and employed as the format for the transfer of an ASCII file capable of being exchanged between any two CAD Systems. The early implementation of IGES translators by the CAD Systems vendors tended to be unreliable – in part because of vagueness in the specification, and in part because some vendors only implemented only a part of the standard. Such difficulties prompted the French company Aerospatiale to develop their own standard, SET (Standard d’Echange et de Transfert), that was eventually adopted by the French National Standards Body (AFNOR) as a standard in 1985, and has since become widely used in the European Airbus industry. SET uses a similar data model to IGES, but with a very much more compact format.

Transfer podataka izme|u CAD sistema i drugih programabilnih sistema Data transfer between CAD Systems and other program systems

CAD System A CAD System B

S T E P

♦ proces planiranja

• pllaning proces ♦ planiranje montaè

• assembly planning ♦ NC-programiranje

• NC-programming

CAP

♦ kontrolisanje

proizvodnje

• manufacturing control

♦ odràvanje transport i skladitenej

• handling, transport and storage

CAM ♦ planiranje

proizvodnje i kontrole

• production planning and control

PPS

♦ programiranje

mjerenja maina

• measurement programming

♦ osiguranje kvaliteta

• quality assurance

CAQ

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Ograni~enja IGES-a su tako|e uticala na njema~ku automobilsku industriju da razvije razvije vlastiti standard, ali u ovom slu~aju cilj je bio da se prevazi|u ograni~enja IGES standarda koji je mogao reprezentovati samo povrine sa kubnom osnovom. Standard VDA/FS (Verband der Deutsche Automobil-industrie Flachen Schnutstelle) je razvijen s ciljem da bi se mogle reprezentovati povrine vieg reda. Druga verzija ovog standarda je tako|e uklju~ivala topoloke i geometrijske informacije. Za vrijeme navedenih doga|aja koji su se deavali u Evropi, rad na IGES-u i drugim eksperimentalnim standardima se brzo nastavljao. IGES verzija 2.0 se pojavila 1983. godine i uklju~ivala je entitete iz aplikacija FE (kona~nih elemenata) i elektri~nih sistema. Premda nikada nije postala zvani~an standard, IGES verzija 2.0 je bila iroko prihvaena u CAD industriji. Iako je IGES dominantan standard za razmjenu podataka izme|u CAD sistema, brojne alternative i varijante standarda su razvijene u proteklom periodu i , tavie, uvjek je bilo odre|enih nezadovoljstava vezano za osnivne principe na kojima je zasnovan IGES standard. Navedeni faktori su poslijednjih godina doveli do zajedni~kog napora da se razvije me|unarodnog standard s ciljem integrisanja ste~enih saznanja i obezbje|enja jedne fundamentalno poboljane osnove za aktivnosti standarda u ovom podru~ju. Specifikacija za razmjenu podataka proizvoda (PDES) je proistekla na bazi inicijative iz 1984. godine od strane IGES organizacije. Pred kraj 80-tih godina prolog vijeka, evropska Zajednica je tako|e finansirala veliki projekat unutar ESPRIT programa (evropski specifi~ni program za istraìvanja i razvoj u informacionoj tehnologiji), nazvan CAD*I (CAD Interfejsi) – Esprit projekat 322 – iz 1989. godine. Ovi razli~iti projekti, i pridruèni rad u ovom podru~ju, su bili objedinjeni od strane ISO organizacije u jedan jedinstven standard nazvan STEP (Standard za razmjenu podataka proizvoda), premda je u Americi i dalje zadràn akronim PDES iz raznih razloga ali mu je zna~enje sada promjenjeno i sada glasi: razmjena podataka proizvoda koristei STEP . Hronoloki prikaz procesa razmjene podataka izme|u CAD sistema je prikazan na slijedeoj slici [3][p196]. Sa prezentovane slike moè se vidjeti da svi nacionalni standardi za razmjenu podataka izme|u CAD sistema teè da slijede i upotrebljavaju ISO 10303 (STEP) kao me|unarodni standard za razmjeu podataka modela proizvoda to tako|e

upuuje na ~injenicu da STEP predstavlja budunost u razmjeni CAD/CAM/CAE podataka. Limitations of IGES also prompted the German automotive industry to develop a standard of their own, but in this case the objective was to overcome the limitations of IGES that could represent only cubic base surfaces. The standard VDA/FS (Verband der Deutsche Automobilindustrie Flachen Schnutstelle) was developed particularly to represent higher order surfaces. The second version has also included topological as well as geometric information. While these developments were taking place in Europe, work on IGES and other experimental standards continued apace. IGES version 2.0 appeared in 1983, and included entities from FE (Finite Element) and electrical system applications. Although never an official standard, IGES 2.0 was widely adopted within the CAD industry. Although IGES is the dominant standard for CAD data exchange, a number of alternative or variant standards have been developed over the years, and furthermore there has always been some dissatisfaction in the underlying bases for IGES. In recent years, these factors have led to an effort to develop an agreed international standard to integrate previous work, and to provide an improved fundamental basis for standards activities in this area. The effort of Product Data Exchange Specification (PDES) grew out of the initiation in 1984, by the IGES organization. In the late 1980s, European Community also founded a large project under ESPRIT Programme (European Specific Programme for Research and Development in Information Technology), called Computer Aided Design Interfaces (Esprit Project 322 – CAD*I - 1989). These various projects, and associated work in the area, have been drawn together by the ISO into a single unified standard called the Standard for Exchange of Product Data (STEP), although in the US the PDES acronym has been retained for various reasons, standing for Product Data Exchange using STEP. Chronological highlights of CAD data exchange process are presented in the following figure [3][p196]. From the above-presented figure it can be seen that all national standards for data exchange between CAD Systems tend to follow and use the ISO 10303 (STEP) as an International Standard for data exchange of the Product Model, which also implies that STEP is the future in the CAD/CAM/CAE data exchange.

- 243 -

Slika 3. Hronoloki prikaz razmjene podataka izme|u CAD sistema

Figure 3. Chronological highlights of CAD data exchange

3. OSNOVNI KONCEPTI I STRUKTURA STEP STANDARDA Digitalni podaci proizvoda moraju sadràvati dovoljno informacija za obuhvatanje cjelokupnog ciklusa ìvota jednog proizvoda od procesa dizajna do analize, proizvodnje, testiranja kontrole kvaliteta, inspekcije i funkcija podrke proizvodu. Da bi sve to bilo mogue uraditi STEP standard mora obuhvatiti geometriju, topologiju, tolerancije, povezanost, atribute, sklopove konfiguraciju i jo monogo drugih relacija. Za postizanje ovako ambicioznog cilja STEP standard je, kao ISO standard, sastavljen iz vie dijelova. Osnovni dijelovi su zavreni i publikovani, dok su ostali dijelovi u razvoju. Ovi dijelovi pokrivaju opta podru~ja, kao to su procedure testiranja, format fajla, programski interfrejs kao i informacije zavisne od industrije u kojoj se primjenjuje. Najva`niji aspekt STEP standarda jeste proirivost. STEP je izgra|en na posebnom jeziku koji moè formalno opisati strukturu i uslove korektnosti bilo koje inènjerske informacije koju je potrebno razmjeniti. Veoma va`ni pristupi za razvoj STEP standarda su bazirani na [2][p202]:

• razvojnoj metodologiji i • konceptu modela proizvoda.

Metodologija razvoja STEP standarda je zasnovana na tri nivoa i bie detaljnije prezentovana kasnije u ovom radu.

3. BASIC CONCEPTS AND STRUCTURE OF THE STEP STANDARD Digital product data must contain enough information to cover a product's entire life cycle, from design to analysis, manufacture, quality control testing, inspection and product support functions. In order to do this, STEP must cover geometry, topology, tolerances, relationships, attributes, assemblies, configuration and more. To accomplish this ambitious goal, STEP has been constructed as a multi-part ISO standard. The basic parts are complete and published, while more are under development. These parts cover general areas, such as testing procedures, file formats and programming interfaces, as well as industry-specific information. The most important aspect of STEP is extensibility. STEP is built on an language that can formally describe the structure and correctness conditions of any engineering information that needs to be exchanged. Very important approaches for the STEP development are based on the [2] [p202]:

• development methodology and the • product model concept.

The development methodology of STEP is based on three layers and will be discussed in detail later in the article.

- 244 -

Koncept modela priozvoda STEP standarda je zasnovana na konceptu generi~kog modela koji uklju~uje koherentnu definiciju svih definicija proizvoda (kontekst definicije proizvoda, definiciju proizvoda, definiciju osobina proizvoda i reprezentaciju oblika proizvoda). Reprezentacija oblika STEP standarda obezbje|uje koncept modela za predstavljanje oblika i veli~ine proizvoda i podràva obje glavne reprezentacije modela ~vrstog tijela (CSG i B-rep). STEP je podjeljen u klase koje se sastoje iz vie dijelova i to [1] [ p18]:

• Uvodni dio, • Deskriptivne metode, • Informacioni modeli, • Implementacione forme, • Metodologija potvrde testiranjem, • Modeli informacionih resursa i • Aplikacioni protokoli

Uvodni dio sadr i samo prvi dio STEP standarda i daje uvod u koncepte STEP standarda i strukture njegovih dijelova. Deskriptivne metode standardizuju metode koritene pri opisu STEP entiteta. Kao prvi primjer moè se navesti jezik za opis podataka - EXPRESS Informacioni model opisuje metode koritene pri razvoju informacionog modela. Takvi dijelovi uklju~uju jezik za specifikaciju modela (EXPRESS) i okvir za modeliranje podataka proizvoda. Okvir definie jedan integrisan model informacija proizvoda (IPIM) koji specificira kako se modeliraju informacije o proizvodima, modele interpretiranja aplikacije koji interpretiraju IPIM da bi obezbjedili funkcionalnost za specifi~nu upotrebu podataka proizvoda. Implementacione forme STEP standarda obezbje|uju logi~ki potpun informacioni model proizvoda koji je u mogunosti da podr i vie implementacionih metoda. Kao primjer moè poslu iti razmjena fizi~kog fajla. Metodologija potvrde testiranjem uklju~uje definiciju standardnih procedura i alata potrebnih za izvrenje potvrde testiranjem proizvoda kojom se potvr|uje da je implementiran jedan ili vie standarda STEP aplikacionih protokola. Modeli informacionih resursa definiu sadràj podataka koji obezbje|uju za razvoj aplikacionih protokola. Oni uklju~uju modele skoro univerzalne primjenljivosti i one koji podràvaju odre|ene aplikacije ili klase aplikacija. Podatak proizvoda se enkapsulira u jednu nezavisnu implementacionu formu i samo se moè primjeniti indirektno preko aplikacionog protokola. Aplikacioni protokoli predstavljaju poboljane modele informacionih servisa s ciljem obezbje|enja specifi~nih funkcionalnosti. Sadr aj logi~kih podataka svakog protokola je dovoljan i kompletan. Aplikacioni protokoli izraàvaju eksplicitno informacije potrebne odre|enoj aplikaciji, specificiraju nedvosmisleno zna~enje pomou kojeg se informacije razmjenjuju za datu aplikaciju i obezbje|uje osnovu za potvrdu testiranjem. Predhodno navedena klasifikacija se moè grafi~ki predstaviti na slijedei na~in:

The STEP Product Model concept is based on Generic Model Concept which includes a coherent definition of all product definitions (the product definition context, the product definition, the product property definition and the product shape representation). The STEP shape representation provides a model concept for representing the shape and size of product and it supports both main solid representations (CSG and B-rep). STEP is devided into Calasses comprising a number of Parts as follows [1] [ p18]:

• Introductory, • Descriptions methods, • Information models, • Implementation forms, • Conformance testing methodology, • Resource information models and • Application protocols

Introductory contains only Part 1 of STEP and provides an introduction to the concepts of STEP and the structure of its Parts Description methods standardize the methods used when describing STEP entities. The data description language EXPRESS is the first example. Information model describes the methods used in the development of information models. Such parts include a model specification language (EXPRESS) and a framework for the product data modelling. The framework defines an integrated product information model (IPIM) that specifies how information about products is modelled and application interpreted models, which interpret the IPIM to provide required functionality for specific uses of product data. Implementation forms of the STEP standard provi-de a logically complete information model of a product, which is capable of supporting multiple implementation methods. Physical file exchange is an example. Conformance testing methodologies include definition of the standard procedures and tools required to undertake conformance testing of products which claim to implement one or more STEP application protocol standards. Resource information models define the data content which provides the basis for the development of application protocols. They include models of almost universal applicability and those which support a particular application or class of application. The product data is encapsulated in an independent implementation form and is only implemented indirectly via an application protocol. Application Protocols are refined from the resource information models to provide a specific functionality. The logical data content of each is self-contained and complete. Application protocols state explicitly the information needs of particular application, specify an unambiguous means by which information is to be exchanged for that application, and provides a basis for conformance testing. The above-mentioned classification can be graphically presented as follows :

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APLIKACIONI PROTOKOLI (AP) APLPLICATION PROTOCOLS (AP)

AP3 AP1 AP2 AP4

...

INFORMACIONI MODELI INFORMATION MODELS APLIKACIONI RESURSI

APPLICATION RESOURCES

Crtanje Drafting

Struktura broda Ship

structure

Elektro Electrical

Model kona~nog elementa

Finite Element Model

OP[TI RESURSI GENERAL RESOURCES

Prezentacija Presentation

Sakupljanje (PSCM, AEC jezgro, dizajn broda)

Aggregations (PSCM, AEC Core, Ship Design)

Oblik 2 (Osobine, Tolerancija, Interfejs oblika)

Shape 2 (Features, Tolerances, Shape Interface)

Materijal Material

Oblik (Geometrija, Topologija, Oblik tijela)

Shape (Geometry, Topology, Shape Solid)

Ostali resursi Miscellaneous Resources

Fizi~ki fajl

Physical File

Radni format Working format

Baza podataka Data Base

Baza saznanja Knowledge

Base ...

DE

SKR

IPC

ION

E M

ET

OD

E —

DE

SCR

IPT

ION

ME

TH

OD

S

IMPLEMENTACIONE METODE IMPLEMENTATION METHODS

PO

TV

RD

A T

EST

IRA

NJE

M

FR

AM

EW

OR

K F

OR

CO

NF

OR

MA

NC

E T

EST

ING

Slika 4. Pregled strukture STEP standarda [2][p198] Figure 4. STEP structure overview [2] [p198]

Slijedea tri aplikaciona protokola predstavljaju dio ISO STEP standarda za razmjenu podataka izme|u CAD sistema i odnose se na podru~je dizajna u mainstvu: • AP204 (aplikacioni protokol za mainski dizajn

koritenjem B-rep reprezentacije modela) • AP205 (aplikacioni protokol za mainski dizajn

koritenjem povrinske reprezentacije modela) • AP206 (aplikacioni protokol za mainski dizajn

koritenjem `i~ne reprezentacije modela)

The following three Application Protocols (APs) are a part of ISO STEP standard for CAD data exchange and are related to the Mechanical Design: • AP204 (Application Protocol for Mechanical

Design Using Boundary Representation) • AP205 (Application Protocol for Mechanical

Design Using Surface Representation) • AP206 (Application Protocol for Mechanical

Design Using Wireframe Representation)

4. METODOLOGIJA RAZVOJA STEP STANDARDA

Metodologija razvoja STEP standarda je zasnovana na tri nivoa. Navedena tri nivoa su: aplikacioni nivo, logi~ki nivo i implementacioni nivo. Nivoi su definisani tako da podr`e razvoj model proizvoda STEP standarda koji je baziran na metodama i alatima koji se moraju korisititi u svakom nivou.

4. THE DEVELOPMENT METHODOLOGY OF STEP STANDARD

The development methodology of STEP is based on the three layer approach. These three layers are: the application layer, the logical layer and the implementation layer. They have been defined to support the development of the STEP product model based on methods and tools which have to be used in each layer.

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Zahtjev STEP standarda je da bude nezavisan od implementacije, aplikacije, koritenog sistema i nacionalnih standarda. Zbog toga, pristup sa tri nivoa se koristi da se izvede formalni oblik specifikacije, funkcionalna analiza modela semanti~kih podataka pri dizajnu i da se izvede, iz formalne specifikacije, specifikacija orjentisana na implementaciju. Tri nivoa podràvaju navedeni process i sadrè slijedee aktivnosti [2] [p200]: • Aplikacioni nivo podràva funkcionalne

analize zasnovane na IDEF metodu i dizajn modela padataka proizvoda koji je baziran na funkcionalnoj analizi. Za dizajn podataka modela proizvoda analize podataka i metode dizajna koriste se IDEF 1X, NIAM i EXPRESS-G.

• Logi~ki nivo sluì da izradu formalne specifikacije. Formalna specifikacija modela podataka STEP standarda moè se porediti sa definicijom konceptualnog modela podataka. Logi~ki nivo je nezavisan od bilo kojeg modela strukture podataka. Za formalnu specifikaciju razvijen je programski jezik EXPRESS koji je objektno-orjentisan i obezbje|uje lokalna i globalna pravila za definisanje ograni~enja.

• Fizi~ki nivo je neophodan da izvede i specificira svrhu implementacie za formalnu specifikaciju. Danas tri nivoa se koriste da se definie fizi~ki fajl, radni format i pristup bazi podataka. Za implementaciju fizi~kog fajla se koristi WSN sintaksna notacija (Wirth Syntax Notation)

Navedeni nivoi se mogu grafi~ki predstaviti kao to je to prikazano na slijedeoj slici: Za kontrolu izvo|enja i rezultata specifikacija koriste se procedure za validnost i verifikaciju. Ove procedure su veoma zna~ajne posebno za kontrolu potvr|ivanja bilo koje implementacije u odnosu na standard. Za ove svrhe su definisane metode za potvrdu testiranjem.

The STEP standard requires to be independent of any implementation, application, system or any national standards. Therefore the three layer approach is used to derive the formal specification from a functional analysis when designing a semantically data model and to derive a implementation oriented specification from the formal specification. The three layers support this process and they contain the following activities [2] [p200]: • The application layer supports the

functional analyses based on the IDEF method and the design of the product data model which is based on the functional analysis. For the design of the product model data the data analysis and design methods IDEF 1X, NIAM and EXPRESS –G are used.

• The logical layer serves to produce the formal specification. The formal specification of the STEP data model can be compared with the definition of conceptual data model. It is independent of any data structure model. For the formal specification language EXPRESS has been developed. EXPRESS is object oriented and provides local and global rules to define constrains.

• The physical layer is necessary to derive and specify the implementation purpose for the formal specification. Today, the three levels are used to define the physical file, the working format and the access to the data bases. For the physical file implementation the Wirth Syntax Notation (WSN) has been used.

The above-mentioned layers could be graphically presented by the following picture: A validation and verification procedure is being used to control the derivation and specification results. The procedures are very important especially for the control of conformity of any implementation towards the standard. For this purpose conformance testing methods have been defined.

Slika 5. Pristup sa tri nivoa STEP standarda

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Figure 5. Three layer approach of STEP

5. STRUKTURA ST RAZVOJNE OKOLINE ST-razvojna okolina predstavlja kolekciju softverskih alata za rad sa setom podataka definisanih EXPRESS jezikom za razna programska okruènja. Komponente ST-razvojne okoline su prikazane na slijedeoj slici [6]:

5. STRUCTURE OF ST-DEVELOPER ST-Developer is a set of software tools for working with EXPRESS information models and EXPRESS-defined data set in a variety of database and programming environments. The components of ST-Developer are shown below [6]:

Slika 6. Struktura ST-razvojne okoline Figure 6. ST-Developer structure

ST-razvojna okolina sadrì SDAI programsko okruènje za C++ i C programske jezike. Ove veze se mogu koristiti za izgradnju softvera koji koristi STEP podatke u objektno-orjentnisanim i relacionim bazama podataka kao i u tradicionalnim fajlovima. Dodatno ST razvojna okolina sadrì alate za modeliranje informacija, definicije pogleda, potvrdno testiranje i pomjeranje naslije|enih podataka. Svaki od slijedeih interfejsa ima odgovarajue prednosti, ali svaki od njih daje mogunost programeru da kreira i manipulie bazom podataka STEP standarda:

ST-Developer contains SDAI programming environments for C++ and C. These bindings can be used to build software that works with STEP data in object-oriented databases, relational databases, and traditional files. In addition, ST-Developer contains tools for information modelling and view definition, conformance testing, and legacy data migration. Each of the following interfaces have certain advantages, but all of them let a programmer create and manipulate STEP data sets:

STEP Objekti Biblioteka jezgra

STEP Objects Core Library

Skladite Repository

Object store Open ODB

Rose files Oracle Versant Part 21 Files

Ostali STEP alati Other STEP Tools

SDAI C, C++, i ostali inter fejsi za programiranje

SDAI C, C++, and other programming Inter faces

CAD alati za integracijuCAD Integration Tools

STEP editor za potvrdui ver ifikator

STEP Conformance Editor and Ver ifer

EXPRESS kompajler i EXPRESSS — G-alati za izradu ema

EXPRESS Compiler and EXPRESS — G Scheme tools

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• ROSE C++ Class Library • SDAI C Library • Part 21 Filter Library

• ROSE C++ Class Library • SDAI C Library • Part 21 Filter Library

6. ZAKLJUÂK

STEP predstavlja sveobuhvatan ISO standard (ISO 10303) za razmjenu podataka modela proizvoda kojim se opisuje na koji na~in je potrebno predstaviti i razmjenuti digitalne informacije proizvoda. STEP je nastao 1983. godine i baziran je na predhodnim saznanjima nacionalnih standarda za razmjenu podataka kao to su: IGES, VDAFS, SET and CAD*I Prednosti STEP standarda kada se poredi sa ostalim standardima za razmjenu podataka izme|u CAD sistema su : • STEP standar pored geometrije definie i ostale

bitne podatke proizvoda • Pomou STEP standarda mogue je definisati i

strukturu proizvoda • Mogunost podrke vie nivoa implementacije

(npr.fizi~ki fajl ili baza podataka) • Mogunost izrade fleksibilnih i pouzdanih

prevodilaca • STEP je standard koji moè da se proiruje.

On je baziran na programskom jeziku (EXPRESS) i moè se proiriti na bilo koju industrijsku granu. Standard koji je proiriv ne moè zastariti nakon prve publikacije.

• EXPRESS jezik opisuje ograni~enja kao i strukturu podataka. Formalna pravila korektnosti e sprije~iti konfliktne interpretacije. STEP CASE alati kao to je ST razvojna okolina koriste navedene opise za kreiranje robusnijeg i za odràvanje lakeg sistema.

I najzna~ajnija prednost STEP standarda bi trebala biti: • Me|unarodna prihvaenost STEP standarda tj.

STEP je me|unarodni standard kojeg su razvili korisnici a ne proizvo|a~i CAD sistema. Standardi pokrenuti od strane krajnjih korisnika su okrenuti ka rezultatima dok su standardi pokrenuti od strane proizvo|a~a okrenuti ka tehnologiji. STEP je preìvio i nastavie da se ide u korak sa tehnologijom i moè se koristiti kao dugoro~no opredjeljenje za arhiviranje podataka proizvoda.

6. CONCLUSION The Standard for the Exchange of Product Model Data (STEP) is a comprehensive ISO standard (ISO 10303) that describes how to represent and exchange digital product information. STEP was born in 1983, and was based on previous national efforts such as IGES, VDAFS, SET and CAD*I. The advantages of STEP standard compared with other standards for CAD data exchange are as follows: • besides geometry, other product data are

defined in the STEP standard • the structure of the product can be defined by

STEP standard • different level of implementation will be

supported, such as physical file or database • flexible and reliable translators can be made • STEP is a standard that can grow. It is based

on a language (EXPRESS) and can be extended to any industry. A standard that grows will not be outdated as soon as it is published.

• The EXPRESS language describes constraints as well as data structure. Formal correctness rules will prevent conflicting interpretations. STEP CASE tools such as ST-Developer use these descriptions to create more robust, maintainable systems.

And the most important advantage of the STEP standard should be: • International acceptance of the STEP standard

i.e. STEP is international, and was developed by users, not vendors. User-driven standards are result-oriented, whereas vendor-driven standards are technology-oriented. STEP has survived, and will continue surviving changes in technology and can be used for long-term archiving of product data.


[1] H.J.Helpenstain(Ed.): CAD Geometry Exchange using STEP – Realisation of Interface Processor, Springer Verlag, 1993.

[2] J.Haschek (Ed.): Free Form Tools in CAD Systems – a comparisons, B.G.Tember, 1991.

[3] C.Mc Mahon,J.Browne: CAD/CAM From Principles to Practice, Addison-Wesley Publisher Ltd,1993.

[4] A.Elisabeth: CAD Product Data Exchange – Conversion for Curves and Surface, Delft University Press, 1991.

[5] P.F.Jones: CAD/CAM – Features, Application and Management, The Macmillan Press Ltd, 1992.

[6] STEP Tools Inc. : ST-Developer v.8 Relase Notes - Manual, STEP Tools Inc., 2000.

Mainstvo 4(5), 249 – 256, (2001) H.Simi~i,...: OBRADA OTPADNIH VODA HEMIJSKE...

OBRADA OTPADNIH VODA HEMIJSKE INDUSTRIJE U VISOKOM TORNJU - BIOREAKTORU

Hajrudin Simi~i, Vahida Selimbai, Tehnoloki fakultet Univerziteta u Tuzli, E-mail: [email protected]

REZIME

Pre~iavanje otpadnih tokova hemijske industrije obi~no predstavlja problem zbog njihovog sastava i karakteristika. Posebno je teko ove vode ~istiti biolokim putem zbog sadràja toksi~nih i teko razgradljivih spojeva. Savremene tehnologije biolokog ~ienja kao to je aktivni mulj u visokom tornju, omoguuju pre~iavanje industrijskih teè razgradljivih otpadnih voda, posebno u kombinaciji sa fekalnom vodom. U tom cilju je na osnovu prethodnih istraìvanja, razra|ena koncepcija biolokog ~ienja organskih otpadnih tokova iz hloralkalnog kompleksa u Tuzli zajedno sa fekalnim vodama. Prednosti ovog sistema pre~iavanja su viestruke a posebno to se vode ~iste u zatvorenom sistemu gdje je mogue kontrolisati i ~istiti otpadne gasove koji sadrè hlorirane ugljovodonike. Pri tome se dobija razrije|ena hlorovodoni~na kiselina za neutralizaciju ulazne otpadne vode.

STRU^NI RAD

Klju~ne rije~i: otpadne vode, hemijska industrija, propilen oksid, bioloka obrada

THE TREATMENT OF CHEMICAL INDUSTRY WASTE WATER IN HIGH TOWER – BIOREACTOR

Hajrudin Simi~i, Vahida Selimbai, Faculty of Technology, Univerzity in Tuzla, E-mail: [email protected]

SUMMARY

The treatment of chemical industry wastewater due to its composition and characteristics is in general connected with many difficulties. It is especially hard to treat the wastewaters biologically because of the toxic and hard degradible compounds. The modern treatment technology such as activated sludge in the high tower - bioreactor make the biological treatment, of such hard degradible wastewater, possible especially the municipal wastewater. On the basis of the previous pilot plant investigation, the conceptual biological treatment of the organic streatms from the chloralcaly complex is designed. The advantages of this system are evident, such as the high efficency of the oxygen intake and energy savings. In addition, because of the closed system, it is possible to control and clean the waste gases containing the toxic chlorinate hydrocarbons. The by- product is dilluted chlorinated acid, which is suitable for the neutralisation of the inlet wastewater.

PROFESSIONAL PAPER

Key words: waste water, chemical industry, propylen oxyde, biological treatment

1. UVOD U proizvodnim procesima "POLIHEM"-a Tuzla nastaju zna~ajne koli~ine otpadnih voda koje su karakteristi~ne po svom sastavu i teretu zaga|enja koje nose. Za ove otpadne vode je predvi|en predtretman i to iz pogona propilen oksida, toluendiizocijanata, elektrolize i kaporita [1,2,3]. Dosadanje koncepcije za kompleksnu obradu ovih otpadnih voda su se zasnivale na njihovom priklju~enju na zajedni~ko postrojenje za pre~iavanje otpadnih voda grada i industrije Tuzle za koje je jo 1982. godine ura|en idejni projekat [3].

1. INTRODUCTION

In the production processes at “POLIHEM” Tuzla a considerable amounts of waste water are generated which are characterised by their composition and pollution load. They are pre-treated from using propylene oxyde, toluenediisocianate (TDI), electrolyse and caporite. [1,2,3]. The existing methods of treatment of these waste waters have been based on their connection to the common treatment plant for the treatment of municipal and industrial waste waters of the town of Tuzla, for which the preliminary design was made in 1982 [3].

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Me|utim, realizacija ovog projekta je odloèna na neodre|eno vrijeme, to zna~i da e veliki zaga|iva~i kao to je Hloralkalni kompleks, nakon privatizacije i pokretanja proizvodnje neminovno doi u situaciju da moraju ~istiti svoje otpadne vode neovisno o planovima za izgradnju gradskog postrojenja. Najnovija saznanja i iskustva u pre~iavanju otpadnih voda hemijskih kompleksa u svijetu (Bayer, Hoechst i dr.), kao i do sada izvrena istraìvanja na ovim vodama [4] pokazuju da je ove otpadne vode mogue pre~istiti do traènog kvaliteta za isputanje u vodotok. Otpadni tokovi iz Hloalkalnog kompleksa sadrè hlorirane ugljovodonike, aromatske nitro spojeve, propilen glikol i druge organske komponente kao i zna~ajni sadràj neorganskih soli i suspendiranih materija. Prvi preduslov za potpuno ~ienje je predtretman ovih otpadnih tokova u samim pogonima do nivoa za bioloku obradu. Ovo podrazumjeva saniranje postojeih ure|aja za predtretmane i njihov efikasan rad [1,2]. Bioloko pre~ivanje u visokom bioreaktoru ima niz prednosti u odnosu na klasi~ne bioloke metode obrade posebno industrijskih otpadnih voda i to [5,6,7]: a) bolje iskoritenje kiseonika iz zraka i do 80-85 %

zbog vee visine vodenog stuba, to zna~i da je potrebno unijeti svega 1/5 do 1/7 od iste koli~ine zraka to se moè unijeti povrinskim aeratorima kod klasi~nih biolokih bazena. Ovo zna~i i zna~ajnu utedu u energiji za unos kiseonika.

b) Eliminiu se aerosolovi, odnosno nema zaga|enja okoline sa neugodnim mirisima i opasnim bakterijama,

c) Iskoriteni zrak i otpadni gasovi se mogu voditi na pre~iavanje to je kod klasi~nih bazena veoma skupo i ~esto neizvodljivo;

d) Sistem ima puferske sposobnosti zbog mogunosti promjene visine vodenog stuba zbog ~ega je znatno elasti~niji u odnosu na klasi~ne bioloke bazene;

e) Zbog gradnje u visinu smanjuje se potrebno zemljite za faktor 3 - 5;

f) Biorekatori se grade od ~eli~nog lima koji je znatno otporniji na promjene vanjske temperature to nije slu~aj kod betonskih bazena koji pucaju i postaju vodopropusni.

However, the realization of this project has been postponed, which means that the big polluters such as Chloralkal complex, after the privatization and back set up into the production, will be in a position to treat their waste water independently of the realization of common treatment plan for the town of Tuzla. Recent knowledge and experience in the treatment of waste water originated from the chemical complexes in the world (Bayer, Hoechst), as well as research [4] have proved that the treatment for discharge of the wastewater in the water stream is possible. The waste streams from Chloralcal Complex contain the chlorinated hydrocarbons, aromatic nitro-compounds, propylene glycole and other organic compounds, as well as a considerable amount of inorganic salts and suspended mater. The first condition for complete purification is pretreatment of this waste stream at the site up to the level for biological treatment. This means the reconstruction of existing pretreatment plants and their effective operation [1,2]. Biological treatment in the high bioreactor (“tower biology”) has many advantages compared to the traditional biological methods, especially in the treatment of industrial waste waters such as [5,6,7]: a) Better oxygen intake up to 80-85 % due to the

high water path ( up to 20 m). It means the oxygen need of only 1/5 to 1/7 of the quantity normally used by surface aerators in the traditional aeration tank. It means a considerable energy saving for the oxygen intake.

b) No aerosols nor the environmental pollution with the odour or bacteria.

c) The waste air and gases are collected and treated, which is not the case in the classical aeration tanks.

d) More flexible system and the puffer capability. e) Lower space requirements due to the high

tower used instead of large tanks. f) Bioreactor is made of steel, the material which

is more resistant to temperature conditions compared to the reinforced concrete tanks.

2. PREÎ[]AVANJE OTPADNIH VODA 2.1. Ulazni podaci Na bioloku obradu se predvi|a da idu predtretirani industrijski otpadni tokovi iz: • Proizvodnje propilen oksida - otpadni tok 1. • Proizvodnje poliola - otpadni tok 2. • Proizvodnje TDI (toluendiizocijanata) - otpadni tok 3. • Fekalne i sanitarne otpadne vode hemijskog

kompleksa - otpadni tok 4.

2. WASTE WATER TREATMENT 2.1. Inlet data

The following pretreated waste streams generated at the production plants of Chloralcaly Complex are treated biologicaly: • Waste water from the Propylene oxide plant - waste stream 1.

• Waste water from the Polyols plant - Waste stream 2. • Waste water from the TDI (toluenediisocianate) plant - waste stream 3.

• Sewage from the Chemical Complex-waste stream 4.

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Ostale otpadne vode ( neorganski tokovi) se tretiraju odvojeno kao i do sada putem fizikalno-hemijske obrade. Koli~ine i sastav otpadnih tokova su dati u Tabeli 1.

Other waste waters (inorganic waste streams) are treated separately by the physical - chemical treatment. The composition and characteristics of waste streams are presented in the Table 1.

Tabela 1. Sastav i karakteristike otpadnih tokova Table 2. Composition and characteristics of waste streams

OZNAKA TOKA - STREAM 1 2 3 4 5 6 7 8

MEDIJ – KARAKTERISTIKE MEDIA-CHARACTERISTICS

WW WW WW WW WW WW WW ML

5496 1320 3120 9936 10.488 10.488 10.488 -

m3/d Koli~ina (max) Flow (max) m3/h 229 55 130 414 437 437 437

4730 864 2580 550 8170 9.332 9.332 9.332

Koli~ina (prosj.) Flow (avarage) m3/h 197 36 107 23 340 388 388 388 HPK - COD kg O2/d 10.990 1080 745 198 12.815 10.450 10.450 2.090 BPK5 - BOD kg O2/d - - - 93,5 - - 3.100 - Temperatura – Temperature °C 40 20-32 20-24 16-20 25-30 20-25 20-25 20-25 pH 7-12 3,5-11 2-13 7-8 5-10 5-10 7-8,5 6,5-8,5 SM, suspended solids SS kg/d 110 90 51,5 100 30250 210 210 26.136 % SM % - - - - - - - 0,3 Hlorirani ugljovodonici Chlorinated hydrocarbons kg/d

140 - - - 140 140 140 2,8

Aromatski nitro spojevi Aromatic nitro compounds kg/d

- - 533 - 533 530 530 106

Neorganske soli Inorganic salts kg/d

110.000 - 29.000 - 139.000 98.000 98.000 98.000

OZNAKA TOKA STREAM

9 10 11 12 13 14 15 16

MEDIJ – KARAKTERISTIKE MEDIA-CHARACTERISTICS

EFLUENT RS SS PS MULJ

SLUDGE TS

FILTRAT FILTRATE

MULJNI KOLA^ SLUDGE

10.488 437 - - - - - - -

Koli~ina (max) Flow (max) m3/h

9.332 4.360 175 820 760 528 620 140 388 182 7,3 34 32 22 26 5,8

Koli~ina (prosj.) Flow (avarage) m3/h

HPK - COD kg O2/d 2.090 - - - - - - - BPK5 - BOD kg O2/d - - - - - - - - Temperatura – Temperature °C 20-25 - - - - - - - pH 6,5-8,5 - - - - - - - SM, Suspended solids SS kg/d 174 30.520 1.230 41.000 42.230 42.230 - 42.230 % SM % - 0,7 0,7 5,0 5,5 8,0 - 30 Hlorirani ugljovodonici Chlorinated hydrocarbons kg/d

2,8

- - - - - - -

Aromatski nitro spojevi Aromatic nitro compounds kg/d

106

- - - - - - -

Neorganske soli Inorganic salts kg/d

98.000

- - - - - - -

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WW - otpadna voda = waste water ML - voda i mulj = mixed liquor RS - povrat mulja = return sludge SS - viak mulja = surplus sludge TS - ugueni mulj = thickened sludge

HPK – COD - hemijska potronja kiseonika = chemical oxygen demand BPK5 – BOD – biohemijska potronja kiseonika = biochemical oxygen demand SM - suspendovane materije = suspended solids

Industrijski otpadni tokovi 1,2 i 3 se prethodno moraju egalizirati u posebnom pufer tanku sa vremenom zadr`avanja od jednog dana. Egalizirana industrijska otpadna voda (tok 5) ima sastav i koli~ine kako je prikazano u Tabeli 2.

Industrial waste streams 1, 2, 3 have to be balanced in a separate equalised tank with the detention time of 1 day. Equalised waste water (waste stream 5) has the characteristics presented in the Table 2.

Tabela 2. Karakteristike egalizirane industrijske otpadne vode (tok 5) Table 2. Characteristics of balanced industrial wastewater (stream 5)

Maksimalna koli~ina, Qmax - Maximum flow 9.936 m3/d Prosjek - Average flow m3/h 340 Teret zaga|enja, HPK - COD loading 12.815 kg/d Koncentracija zaga|enja, HPK - COD concentration 1.200-2.000 mg/l Temperatura, T - Temperature 20,25 oC PH – vrijednost - pH 5 - 10 Suspendirane materije, SM - Suspended solids 251 kg/d Hlorirani ugljovodonici - Chlorinated hydrocarbons 140 kg/d Aromatski nitro spojevi - Aromatic nitro compounds 633 kg/d Neorganske soli - Inorganic salts 110.000 kg/d

Poslije egalizacije u sistem se uvodi fekalna voda hemijskog kompleksa koli~ina i sastava kako je dato u Tabeli 1. (otpadni tok 4.) Nakon mjeanja, talo`enja i neutralizacije i uvo|enja procjedne vode u bioreaktor ide otpadna voda koli~ine i sastava kako je dato u Tabeli 3.

After the equalisation, the sewage of the chemical Comlex is introduced in to the system with the composition and characteristics presented in the Table 1. (waste stream 4). After the mixing, settling and neutralisation and addition of the drainage water, the bioreactor is filled with the waste water with the characteristics shown in the Table 3.

Tabela 3. Koli~ine i karakteristike otpadne vode u bioreaktor Table 3. Quantity and characteristis of wastewater to bioreactor

Srednja koli~ina, Qsr - Average flow 9.332 m3/d Prosje~na koli~ina, Qsr - Average 388 m3/h Teret zaga|enja, HPK - COD loading 10.450 kg/d Teret zaga|enja, BPK5 - BOD loading 3.100 kg/d Temperatura, T – Temperature 20,25 oC PH – vrijednost – pH 7 - 8,5 Suspendirane materije, SM - Suspended solids 210 kg/d Hlorirani ugljovodonici - Chlorinated hydrocarbons 140 kg/d Aromatski nitro spojevi - Aromatic nitro compounds 530 kg/d Neorganske soli – Inorganic salts 98.000 kg/d

2.2. Opis tehnolokog procesa pre~i~iavanja otpadnih voda

Na shemi, slika 1. je prikazan tehnoloki postupak pre~iavanja otpadnih voda. Industrijski otpadni tokovi nakon odgovarajuih predtretmana u pogonima, dopremaju se iz prihvatnog ahta (1) pumpom prvo u egalizacioni bazen (2) ~ija je namjena da se izvri ujedna~avanje protoka i koncentracije zaga|enja industrijskih otpadnih tokova.

2.2. Description of waste water treatment process

The flow chart of the treatment process is given on the diagram, Fig. 1. Industrial waste streams after the proper pretreatment at the plants are pumped from the inlet basin (1) to the equalisation tank (2) in order to equalize the flow and concentration of industrial waste waters.

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U egalizacionom bazenu se vri aeracija sa komprimiranim zrakom ~ime se vri intenzivno mjeanje a ujedno i dodatno stripovanje hloriranih i hlapivih organskih komponenata iz otpadne vode, kao i izdvajanje taloga kalcijevog karbonata i neizreagovanog kalcijevog hidroksida. Egalizacioni bazen je pokriven a izdvojeni gasovi i zrak idu u sistem za tretman otpadnih gasova (10). Nakon egalizacije voda ide u talo`nik (3) gdje se dodaje i fekalna voda i gdje se izvri taloènje izdvojenih taloga. Talo`nik je tako|e pokriven i spojen na sistem za ~ienje otpadnih gasova. Istaloèna voda ide u bazen za neutralizaciju (4) gdje se izvri potrebna neutralizacija a talog se pumpom alje u ugu~iva mulja (8). Neutralzacija je potrebna za obezbje|enje sistema u slu~aju zastoja na predtretmanima. Neutralizacija se vri automatski u zadatom podru~ju preko sistema za mjerenje i regulaciju pH vrijednosti i magnetnih ventila za doziranje kiseline ili baze. Voda se zatim pumpa u biorektor (5) preko posebnog sistema injektora u koje se istovremeno ubacuje komprimirani zrak ~ime se ostvaruje intenzivno mjeanje vode i zraka kao i mjeanje sadràja u bioreaktoru. Preko sistema za mjerenje i regulaciju sadràja kiseonika u bioreaktoru vri se potrebno doziranje komprimiranog zraka u sistem.

The equalisation basin is equipped with the diffused aeration for mixing and additional stripping of chlorynated and volatile organic components, as well as the removal of suspended calcium carbonate and non-spent calcium hydroxide. The equalisation tank is covered in order to control and treat the generated waste gases in the waste gases treatment unit (10). After the equalisation the water flows to the settling tank (3) where the sewage is added. The settling tank is also covered on the top and connected to the gas treatment system. The clear water flows to the neutralisation tank (4). The sludge is pumped from the settling tank to the sludge thickener (8). The neutralisation is needed in the case of delay in pretreatment. The neutralisation process goes automatically. After the neutralisation, the water is pumped to the bioreactor (5) through a special injection system with the compressed air for intensive mixing of the water and air. The concentration of dissolved oxygen in the bioreactor is controlled by a special measuring system.

Slika 1. Shema pre~iavanja otpadnih voda "POLIHEM-a" u bioreaktoru sa aktivnim muljem

Figure 1. Block diagram of wastewater treatment in bioreactor with activated sludge Izdvojeni gasovi i zrak se izvode sa vrha reaktora i vode u sistem za izdvajanje hloriranih ugljovodonika. Na vrhu reaktora se po potrebi rasprava pre~iena voda kako bi se sprije~ila pojava pjene na vrhu reaktora. U reaktor se ubacuju soli fosfora za obezbje|enje biolokog sistema. Tako|e, u sistem se povremeno dodaje kultura adaptiranih mikroorganizama.

The outcoming gases from the top of the reactor are leaded to the waste gas system for removal of chlorinated hydrocarbons. For nutrient requirements of the bilogical system, the phosphorus salts are added in the reactor. Adapted microorganismus ar also added in the bioreactor from time to time.

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Nakon vremena reakcije u bioreaktoru, voda i aktivna biomasa ( mulj) idu u talo`nik (6) gdje se vri separacija mulja iz te~nosti. Bistri preliv kao pre~iena voda odlazi u kontrolni bazen (7) a odatle u vodotok preko mjera~a protoka. Istaloèni mulj se pumpom vraa u bioreaktor a viak biolokog mulja se povremeno izdvaja iz sistema i vodi u ugu~iva (8). Tretman mulja sa postrojenja se sastoji u uklanjanju vode iz mulja u ugu~ivau (8) i zatim na filter presi sa trakom (9). Muljni kola~ sa oko 30 % suhe materije se kontejnerima odvozi na deponiju.

After the bioreactor, water and activated sludge are separated in the settling tank (6). The clear effluent flows to the control tank (7) and then to the water course through the flow measuring device. The settled sludge is pumped to the bioreactor. The surplus sludge is temporary removed from the system and leaded to the sludge thickener (8). The treatment of the sludge consists of sludge thickening in the thickener (8) and dewatering on the belt filter press (9). Dewatered sludge with 30 % of dry matter is transported to the landfill.

2.3. Kvalitet pre~iene vode Na bazi istraìvanja bioloke obrade ovih otpadnih voda u laboratorijskim i poluindustrijskim uslovima (1,2,3) kao i o~ekivane efikasnosti bioreaktora, moè se pretpostaviti o~ekivani kvalitet efluenta iz postrojenja za pre~iavanje: Koli~ina vode, Qsr = 9.930 m3/d Biohemijska potreba kiseonika, BPK5 = 30 mgO2/l Hemijska potreba kiseonika, HPK=150-200 mgO2/l Temperatura, T = 20 - 25 oC PH - vrijednost 6,5 - 8,5 Suspendirane materije, SM = 30 mg/l Hlorirani ugljovodonici 106 kg/d Neorganske soli 30.000-90.000 kg/d Efikasnost pre~iavanja prema stepenu uklanjanja tereta zaga|enja iznosi: HPK 75-85 % BPK5 95 % Hlorirani ugljovodonici 99 %

Aromatski nitro spojevi 83 %

2.4. Veli~ine osnovnih aparata i ure|aja postrojenja

U Tabeli 4. su dati gabariti i dimenzije osnovnih jedinica postrojenja za pre~iavanje otpadnih voda Hloralkalnog kompleksa u visokom tornju (bioreaktoru).

2.3. Effluent quality On the basis of the previous research on treatment in the lab and pilot scale (1,2,3), and the efficiency of bioreactor, one can assume the expected quality of the effluent from the waste water treatment plant is as follows: Flow Qsr = 9,930 m3/d Biochemical oxygen demand BOD = 30 mgO2/l Chemical oxygen demand COD=150-200 mgO2/l Temperature T = 20-25 oC pH 6,5 – 8,5 Suspended solids SM = 30 mg/l Chlorinated hydrocarbons 106 kg/d Inorganic salts 30,000 –90,000 kg/d The efficiency of the treatment regarding the removal of the pollution load will be: COD 75-85 % BOD 95 % Chlorinated hydrocarbons 99 % Aromatic nitro compounds 83 %

2.4. Dimension and basic parameters of main treatment units

The Table 4. present the dimension and basic parameters of the main units of the waste waters treatment plant at the Chloralkaly Complex in the high tower – bioreactor.

3. ZAKLJU^CI Otpadne tokove hemijske industrije kakva je proizvodnja propilen oksida, poliola i toluendiizocijanata, je mogue pre~iavati biolokim putem u visokom tornju - bioreaktoru sa aktivnim muljem. Industrijski otpadni tokovi se moraju prethodno tretirati do potrebnog nivoa za bioloku obradu. U bioloki sistem obrade je potrebno uvoditi fekalnu vodu hemijskog kompleksa za unos potrebnih nutrijenata i to fosfora, dok se azot nalazi u dovoljnoj koli~ini u industrijskoj otpadnoj vodi.

3. CONCLUSIONS Industrial wastewaters generated from the production of propylene oxyde, polyols and toluenediisocyanate can be treated biologically in a high tower - bioreactor with activated sludge. Industrial streams have to be pretreated properly to the level of biological treatment. Fecal wastewater from the chemical complex is added to the biological system for nutrient requirements, especialy phosphorus, whereas the concentration of nitrogen is sufficent in the industrial wastewater.

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Na osnovu poluindustrijskih i laboratorijskih ispitivanja je koncipirana bioloka obrada egalizirane i istalo`ene otpadne vode hloralkalnog kompleksa u 20 m visokom bioreaktoru sa injektiranjem vode i zraka pomou dizni posebne izvedbe. Potrebno vrijeme kontakta vode i aktivne biomase u reaktoru iznosi 14-16 sati to je dovoljno za bioloku razgradnju teko razgradljive organske materije. Tehnologija obrade otpadne vode u visokom bio-reaktoru ima znatne prednosti u odnosu na klasi~ni sistem sa aktivnim muljem to se odnosi prije svega na bolji unos i iskoritenje kiseonika, utedu energije i prostora i to je najva`nije, efikasnije pre~iavanje i kvalitet efluenta koji se mo`e ispustiti u vodotok. Tako|e, poto je sistem zatvoren, otpadni gasovi se kontroliu i vode na poseban tretman - apsorpciju pri ~emu se dobija hlorovodoni~na kiselina potrebna za neutralizaciju otpadne vode.

On the basis of the pilot and bench scale research, the biological treatment of balanced and pretreated wastewater in the 20 m high tower - bioreactor is designed. Oxygen is supplied with the compressed air by special nozles and injected to the biological system together with the inlet wastewater. Detention time of the water in the bioreactor is 14 to 16 hours and is sufficient for bilological degradation of hard degradible organic matter. Industrial wastewater treatment in such bioreactor has many advantages, such as better efficiency of oxygen intake, energy and space saving and better effluent quality for discharge to recipient. In addition, because the system is closed, it is possible to control and clean the waste gases which are treated in the scruber system. The by - product is dilluted chlorinated acid used for the neutralisation of inlet wastewater.

LEGENDA - LEGEND 1. Ulaz otpadne vode - Wastewater inlet 6. Zrak - Air supply 2. Injektor - Injector 7. Talo`nik - Settling tank 3. Ventilacija - Ventilation 8. Zrak - Air supply 4. Ciklon - Cyclone 9. Pre~iena voda - Effluent 5. Recirkulacija mulja - Return sludge

Slika 2. Shema biolokog pre~iavanja otpadne vode u visokom tornju - bioreaktoru Figure 2. Diagram of bilogical wastewater treatment in high tower - bioreactor

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Tabela 4. Veli~ine i dimenzije osnovnih aparata/jedinica postrojenja za pre~iavanje otpadnih voda Table 4. Dimensions of basic units /equipment of wastewater treatment plant

Broj No

Naziv aparata/jedinice Name of unit

Kom ps.

Zapremina Volume m3

Dimenzije Dimension

m

Potreba kiseonika Oxygen Demand kgO2/h

Potreba zraka Air supply Nm3/h

Vrijeme zadràvanja

vode Detention time of water h

1 [aht za pumpu Intake basin

1 20 2x4x2,5 - - 0,06 (3,71')

2 Egalizacioni bazen Egalisation tank

1 8000

(2x4000) 18x15,7x16,7 2.000 - 24

3 Primarni talo`nik Primary clarifier

1 400 R=15,2 H=2,8

- - 1

4 Bazen za neutralizaciju Neutralisation tank

1 195 10x8x2,5 - - 0,5

5 Biorektor Bioreactor

1 6.200 R=20 H=20,5

3.200 640 14-16

6 Talo`nik Settling tank

1 940 R=15 H=14,5

- - 2,4

7 Kontrolni bazen Control tank

1 200 10x10x2 - - 0,5

8 Ugu~iva~ mulja Sludge thickener

1 72,5 R=6 H=3

- - -


[1] Rekonstrukcija postrojenja za predtretman otpadnih voda na pogonu za proizvodnju propilen oksida, Izvedbeni projekat, Institut za hemijsko inènjerstvo Tuzla, 1989.

[2] Rezultati poluindustrijskih istraìvanja smanjenja zaga|enja otpadnih voda iz proizvodnje propilen oksida biolokim tretmanom sa aktivnim muljem u koloni, Elaborat Institut za hemijsko inènjerstvo Tuzla, 1989.

[3] Idejni projekat postrojenja za pre~iavanje otpadnih voda grada i hemijske industrije Tuzla, Institut za hemijsko inènjerstvo i DHV Holandija,Tuzla 1982.

[4] Simi~i H., Mogunost biooksidacije organskih spojeva iz otpadnih voda Hloralkalnog kompleksa Tuzla zajedno sa komunalnim otpadnim vodama, Doktorska disertacija, Sveu~ilite u Zagrebu 1986.

[5] Bauer A., Development trends in construction and chemical engineering of biological waste water treatment plants taking Hoechst AG as example, Hoechst Frankfurt/M, 1980.

[6] Pascik I., Treat waste water biologically, Hydrocabon Processing, 1980.

[7] Zlokarnik M., Verfahrenstechnik der aeroben Abwasserreinigung, Chem. Ing. Tech. 54, 1982.

[8] Metcalf and Eddy, Inc.Wastewater Engineering, Treatment, Disposal and Reuse, McGraw-Hill, Inc. N.York, St. Louis, S.Francisco, International 3 d Edition 1991.

[9] Corbitt R.A., Standard Handbook of Environmental Engineering, Mc.Graw.Hill, Inc, N.York, S.Francisco, 1990.

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