multi - fuel boiler technology

8/3/2019 Multi - Fuel Boiler Technology

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MULTI-FUEL BOILER TECHNOLOGY

RICK A. HAVERLAND

SYSTECH Corporation (SYSTECH)Xenia, Ohio

ABSTRA

The paper presents he concep o resource recoveryas an energy managemen aeative or industrieswith lite or no waste ue o their own Two ypicaprojects and he multiue boiler equipment used oreach proect are described Aso, he technical merits

o he multiue boier and hea recovery incineraion(HR) echnologies are compared

NOMENCLATURE

Btu British hermal unito C degrees Celsiuso degrees ahrenheit cubic eeG gigaga galonhr hourHR hea recovery incinerator induced dratJ Joulekg = kilogramkW kiowatkWh kiowat hour iter

lb pound

m cubic meerMc thousand cubic eet

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MPa megapascalNm norma cubic meterpsi pound per square inchR reusederived ue meric onW wasederived uel

INTRODUION

The energy availabe rom wases generaed by anindusria aciiy rarey maches the energy demando the aciity Mos o the indusria HR systems havebeen insalled at aciities where he energy demand isgreaer han or equal to the energy avaiabe romcombusting the wases generaed a he aciity Thisis probably because both wase disposa and ue savings are availabe or recovering he cos o he HRsystem The industries wih arge amouns o waseand ite energy demand may have considered an HRsystem but a system could not be ustied wihou theenergy savings arge energy users wih smal amounso combusible wases woud probaby no consider anHR sysem because they have no waste but they mayhave considered the insalaion o coa or woodredboilers to repace heir oi or gas boilers Thereore, apossible approach or developing indusria waseto


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FIG. 1 MIXTURE O WASTE DERIVED FUELS

energy is to install (at a aility with a large energydemand) a oiler system apale o using a variety owastes rom industries with little energy demand andother solid uels

There are a variety o oiler system tehnologiesthat an utilize a variety o wastes and solid uels.Beause this energy management approah may require the purhase o wastes and uels the oiler system must e energy eient Also most industrialsystems will proaly e in the size range where atoryassemled (pakaged) oiler systems are the mosteonomial The multiuel oiler tehnology is oth

energy eient and availale in pakaged systemsThereore one possile approah or developing industrial wastetoenergy projets is to install (at a largeenergy user's site) a oiler system that is apale ousing a variety o wastes rom neary industries orother low ost solid uels

Following are projet desriptions or two multiuel oiler installations in Belgium that use a variety owastes rom neary industries as their uel soure. Alleonomis are given in US dollars.

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PROJECT DESCRIPTIONS

The rst Belgium ompany produes paking materials and needed an average o 2 /hr (55kg/h) o 75 psi (2 MPa) saturated steam hr/day 240 day/yr. Their existing uel was naturalgas nd they were using 5322 M/year (5072Nm/year) or a total annual uel ost o $30440 at$5/M (U$ 020/Nm)

The gasred oiler was replaed with a N VVynke multiuel oiler with a rated apaity o7 l/hr (8 kg/h) The ost o the omplete

multiuel oiler system inluding the storage systemoiler multilone ID an stak and oiler eed onveyor was $29 in early 984. Beause the ompany has no waste uel they must purhase uel onthe soliduel market. They are using variale mixtureso ark reusederived uel (F) wood waste pel

letized F pelletized rewery waste peat lignitewaste plastis and textiles (see Figs 3). The totalannual uel onsumption and ost is approximately3 tons (5742 t) and $830 Thereore the average


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FIG 2 PELLEIZED PAPER WASES

cos fo solid fuels is $3.4/on ($5./). ssumin a vey consevaive eain vaue of 45 Bu/b(0.5 J/k), e aveae fuel cos is $5/06 Bu($44/G)

e eciency of e boile vaes sinicany dependin upon e fue bein used Usin een woodwase wi a ie eain value of 440 Bu/b anda moisue conen of 50%, e eciency of e mulifue boie usin e SME Powe es Code is appoximaey 3% Usin seec indusial wase wia ie eain value of 758 Bu/lb and a moisue

conen of 5%, e mulifue boile eciency is 77%.Compaed o e naua as boile sysem, emuifue boile sysem equies an addiional manou/day of opeaion and mainenance abo $/manou e addiional annua abo cos is$880 e mulifuel boile sysem aso uses 50 kWmoe of eleciciy an e as boile sysem fo anannual cos of $0,50 wen eleciciy aes ae$0.055/kW.

Based on ese values, e annual savins usin emuifue boile ae $0,870 neecin capial coss.

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e payback peiod (invesmen/annua savins excludin capial coss) is 4 yeas

e second company also poduces packin maeialand needed an aveae of 8 lb/ (3 k/)of 58 psi (04 MPa) sauaed seam /day, 40days/yea. e exisin boile used No fue oi ase fue, wi an annua consumpion of 90,4 a(,099,4 L) and an annua cos of $8,09. iscoesponds o a uni pice of $0785/ al ($0.08/ ).

e oiled boile was eplaced wi a N. V. Vynckemulifue boie wi a aed capaciy of 0,5b/ (4775 k/) of 30 psi (. MPa), 53F (80C)supeeaed seam wic is expanded ou a sinesae backpessue ubine o poduce 0 kW of elecic powe. e cos of e sysem includin soaesysem, boie, muliclone, ID fan, sack, boie feedconveyo, ubine eneao, and wae eamen sysem was appoximaey $4, in lae 983 eyalso pucase simila fuels as e oe company one solidfues make. e oa annua fue consumpion is 470 ons (47 ), and e annual fuecos is $70,5 e aveae cos of e fue is e same


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FG 3 PELLETIZED BEWEY WASTES

as e oe company e mulifue boile and eecica eneaion sysem as a mainenance budewic is $8,8 moe an fo e oiled boie eelecica usae by e muifue boie sysem is 0kW moe an e oied boile fo an addiionalannua cos of $8,8 Howeve, e muifue sysempoduces 10 kW wi an annua value of $33,79

Based upon ese values, e annua savins usine mulifue boile coeneaion sysem is $17,10,neecin capia coss eefoe, e payback peiodis 3 yeas

EQUIPMENT DESCRIPTION

Bo of e mulifuel poecs descibed in is pape uiize e same boie sysem e equipmen eneay consiss of a soae conveyo, a feed conveyo,a muifue boie, auomaic as emova sysem, aipoluion conol equipmen, fan, and sack Onefaciliy also as a supeeae secion on e boile and

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a ubine eneao e equipmen unique fo use ofmulisolid fuels ae e soae conveyo, e feedconveyo, and e boie moe deailed descipionof ose iems folows

Storage Conveyor

l e fues fo bo faciiies ae deiveed by uck,soed on a coveed concee pad, and loaded, asneeded, ono e soae conveyo by a fonend

loade One of e faciiies as a live boom soaeconveyo (Fi ) a can eceive diec discae ofe fuel fom e deivey uck e ive boom ooconsiss of ydaulicalyacuaed ecipocain seefames e second faciiy as wo elevaed be soae conveys feedin one conveyoo allow blendinof dieen fuels ou bo ypes of soae conveyos ave woked wel, e be conveyo causesmoe ousekeepin poblems and equies moe opeain labo.


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FIG 4 LIVE BonOM SORAGE CONVEYOR

Feed Coveyor

bo aciiies e fes are fed o e boier inan incined be conveyor and an incined feed cewi pnemaic doors o preven ramp air from enerin e boier e feed conveyor as a sre opperwi a eve indicaor o conro e sorae conveyore feed conveyor (Fi. 5) meers e fe fed o eboier by e ei of e ps paes on e be foo mc fe is on e be, e fe wi mbe back

down e seepyincined (45 de) bee feedin sysem aows aomaic feedin of efes on a reaivey coninos basis raer an feedin are baces. e maximm dimension of e fea can be fed is dependen on e sie of e boierand moisre conen of e wase For ese boiers,e maximm fe dimension is 43 in erefore, eaomaic and reaivey coninos feedin can beacieved wi minima or no sreddin

e aomaic feedin redces abor coss, and ereaivey coninos feedin aows combsion a

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near seady sae condiions on a niform dep febed. o dae, e ony operaion probem wi e feedconveyors a eier faciiy as been wen e fedensiy was ess an 0 b/f (160 k/m) Wenis occrred, e ow densiy fes roed back downe conveyor, and e proper mass feed rae o eboier cod no be aained o sove e probem,denser fes were sed, and roer weis were pacedon e conveyor.

Multi-Fuel Boiler

Bo boiers are e JUMBO ) series boier manfacred by N V Vyncke of arebeke, Beime boier is a packaed (facoryassembed) ni consisin of a separae frnance and convecive secion(Fis. 6 and 7) e face secion is formed of waerbes in a modied arc conraion o aow considerabe radian ea ransfer wio ame impinemen on "cod ea ransfer sfaces e convecive


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FIG 5 DOSING BEL FEED CONVEYR

secn e be cnsiss w passes naeube bundes e supeeae secn a e neaciy is an eena mdue added a e end (ppsem e unace secin e cnvecive secinW ead e ue as w, e supeeae sbeween e w passes e cnvecive secin As neaive pessue s mainained in e beunace by e D an and a ue as mduain vaveUndee cmbusin ai is suppied by a ceddaan e a undee a s dvided n ee nes

unde e ae e a w eac ne can becned bee cmbusn wen e ue caneis made e vee cmbusn ai s induced by eneaive pessue in e unace

e unique eaue s muue be is encined waeced sepae skn sysem eae bens a e base e ncned eed cue Eacwaeced sep is an inea pin e beea anse suce and is cnneced b e seamand mud dums e ue is mved dwn e ae bya seies pus paes beween eac sep e paes

ae nmay eaced bu ae pneumacay eended pus e ue ne sep and dwn e nesep is acin and e spe e ae pducesa eavey unim ue bed dep e unm beddep aws d cmbusin cn and ue bunu e bies a b cmpanes ae desned amamum ue misue cnen 5% bu e bemanuacue eped avn e muiue bensaans a ae desned a maimum uemsue cnen 0%

Eac e bes is equpped wi a a pscmbusin ae wc eans e ue un cmbusns cmpee e ne as as in e as ppewen e ae s pneumacay pened Any aeas paices ae manuay pused e end epscmbusn ae in e as ppe A pneumacayacuaed am puses e n e ppeu a ap d e as cnvey e ascnvey ansps e dy as a cnane Oneaciy as a bucke as cnvey we e e asa dacan as cnvey


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FI 6 PACKAED MULTIFUEL BOILER

These two facilities have operated since early 1984with little or no unscheduled downtime and no majoroperational problems.

TECHOLOGY DSCUSSO

There is a fundamental dierence in design philosophy between the multi-fuel boiler and HRI technologies The primary design criteria for multifuel boilersis hot water or steam production, while the primarydesign criteria for HRI systems is waste incinerationLike all fossil fuel boilers and the more ecient elderected HRIs, the fuace of a multifuel boiler is anintegral radiant heat transfer section of the boiler whilemost packaged HRI's are typically an incinerator (oneor more chambers) followed by a heat recovery boilerFollowing is a comparison of multifuel boilers andHR's

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The feeder for a multifuel boiler has an open discharge to the inclined grate in the fuace while thefeeder for an HRI pushes the new charge against previous charges This requires the HRI feeder to pushsome or all of the waste in the fuace forward to asmall step or the ash discharge Since the HRI feedermust develop substantially more force the multifuelboiler feeder has lower power and maintenance costsand higher reliability.

The multifuel boiler fuace has watercooled wallsthat are an integral portion of the boiler while theHRI fuace is completely refractory lined The multifuel boiler fuace will provide higher eciencies because of considerable radiant heat transfer The radiantheat transfer prevents high ue gas temperature in thefuace by recovering energy from the gases when thefuel has a heating value over 5Btu/lb An HRIuses considerable excess air or water sprays to preventhigh ue gas temperatures when high Btu wastes are


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d cas of h watwalls th mli-fl boilfac has considably lss facoy which sholdsbsantially dc factoy mainnanc costs hata sally high fo incinaos h wawalls alsopovid low skin tmpas (150 max) which asaf fo psonnl and dc th pontial of hni compad to an HRI h watwalls also dc

.

ha losss fom th fnac which impovs h cincy and povids mo comfoabl woking condiions

cas mlifl boils a opad a xcss aicondiions h nits hav lss potnial ash slaggingo "png poblms and a simpl o contol hana HRI

h mlifl boil fac chamb is high hanan HRI (appoximaly 10 f vs ft) h gatfnac high allows b mixing of gass fopop combstion wiho having am impingmnton h walls o ciling of h fnac lam imping

mn on facoy o hat tansf sfacs can shotnth lif of h sfac

h mltifl boil fnac has an inclind (appoximaly 25 dg) ga ath han a laivly afacoy hath fond in mos HRI's Mliflboil manfacs s facoy haths in som ofhi boils bt only fo homognos fls wih lowmoist and ash connts sch as kilndid woodh inclind ga podcs b fl bd agitationand allows h fl o mbl down h ga whash wass mst b pshd hogh mos packagdHRIs h pshods bwn h gas of th mlti

fl boil qi vy litl pow bcas thy onlyhav o psh a small amont of was a small distancbfo i falls o th nxt stp h massiv facoyams in mos packagd HRI nis ms psh lagamons of was fo p o onhalf of th nti lngthof th pimay combsion chamb A considablfoc is qid o mov ths ams which a sallyopad sing high pss hydalic sysms hpshods sd in h mli-fl boil a opatdpnmaically sing a small compsso h opnings

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fo h pshods also povid an vn distibion ofth nd ai

h s of a watcoold gat instad of a factoy hah has many advantags h ha ansffom h fl bd impovs h boil cincy andalso dcs th potntial fo ash slagging h wacooling kps h gats cool to xtnd hi lif

Mlifl boils s a dy ash handling sysminstad of a qnch tank commonly sd fo packagHRI sysms h dy ash sysm dcs coosionpoblms and liminas h cos of haling and disposing th wat in h ash If concd abot hoashs qnch spay can b addd to h dy sysm

Sinc th mltifl boil fac is an ingalpotion of th boil th a no dmp stacks o longho gas dcs o a wast hat boil as in an HRIhs hot dcts on HRI sysms can b sponsiblfo considabl ha losss and a xpnsiv o installand maintain

h typ of ai pollion conol qipmn qiddpnds pon h fl and th local mission standadsfo boh chnologis Howv th ncontolld missions fom an HRI a appoximaly qal to hmission fom a mlifl boil with a mlticyclonspaao

CONCLUSIONS

(a) Slc wass and wastdivd fls can b ffcivly ilizd as an alativ fl fo a mliflboil faciliy

b Mlifl boils a an atactiv option o ngy ss hat gna lil o no combsibl wastsof hi own

c Mlifl boils a an conomically atacivaltnativ o incinatos wih ha covy boilsfo slc wasts minimally pocssd wasts andwasdivd fls

Key Words: oil; Cognaion; Engy; l;Rfs Divd Fl

multi - fuel boiler technology

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