D liu cho trc : Cng sut ca thp chng ct :Qv = 6,5 triu tn/nm = 21666,67 tn/ngy (Nh my hot ng 300 ngy mt nm )Gi s :-Thp chng ct kh quync 50 a-Sn phm nh: Kh + naptha-Kerosen ly ra a 15 -LGO ly ra a 25-HGO ly ra a 40-Vng stripping y thp c 5 a-p sut ti nh: 1,5 atm, tn tht p sut trn tng a l 8 mmHg-Nguyn liu u vo l du th Bch H.* Yu cu tnh ton:-Tnh nhit , lu lng Q ti cc vng ca thp-Tnh ton cu trc thp- Thit k bn v PFD cho phn xng CDU -Xy dng bn v P&ID cho mt thit b A. TNH NHIT , LU LNG THP CHNG CT KH QUYNBng A.1. c trng du th Bch HSTT TINH CHT C BAN CUA DU TH KQ PHN TICH1 Tytrong, 0APITytrong, d6060 0FKhi lng ring 150C, g/ml40,20,82410,82362 Ham lng khi (C1-C4) ho a tan trong du, %KL -3 Ham lng lu huynh, %KL 0,0414 im chay, 0C 365 Hng s c trng K UOP 12,396 nht ng ho c 500C, cSt700C, cSt5,2863,4347 Trong lng phn t 240,58 Ham lng parafin, %KL 27,239 Ham lng nc, %TT 0,2010 Ham lng tro, %KL 0,01411 Ham lng Nit, %KL 0,03212 Ap sut hi bao hoa Reid, psi 3,7913 Ham lng tap cht c hoc, %KL 0,00514 Chi s axit, mgKOH/g 0,03715 Cok Conradson, %KL 0,8216 Ham lng mui NaCl, mg/kg 51,3217 Ham lng nha, %KL 1,8818 Ham lng Asphanten, %KL 0,5019 Ham lng Vanadi, ppm 10 cm (ln hn chiu cao chp l 9,52 cm).Nu dng a 1 dng: Vi tit din ng chy chuyn bng 8% din tch a th di b chn L ca ng chy chuyn l 68% D hay 879,5cm . T s QL/L= 288339,8 /879,5= 327,85 cm2/s Theo biu H 4.19[1] th gradien mt lngi ng vi1dy chp khong10 mm. Khi l/d = 0,37 th s chp ti a trn 1 dy l dD37 , 1= 48 , 15 . 37 , 14 , 1293= 61 chp S dy chp l: 2357 /61= 39 dy Vy gradien mt lngi 39= 39.10 =390>>25cm .Kt qu tnh s b cho thy phi dng a 2 dng.B tr chp;Trn mt a, cc chp c sp xp theo quy lut tam gic u nh hnh bn.Nu la chna 2 dng1 bc :Phn trc ta chn a c 16 % din tch l ng chy chuyn. Trong ng chy chuyn gia chim 8%; 2 ng chy chuyn 2 bn mi ng 4% .Theo biu H 4.30 [1] th chiu di b chn ng chy chuyn bn l : 52% D hay 672,6 cm . ng chychuyn gia chim 8% din tch a hay 96972 cm2 . Do b rng ng chy chuyn khong 75cm .Mt a nhn t trn xung mi bc c 1179 chp c xp thnh 19 hay 20 dy khi dng chy t 2 bn vo gia. Cn khi dng chy t gia ra 2 bn th s dy c th nhiu hn, l trnh dng lng qua vng m s ln hn. dy trung bnh h ca lp lng trn a ch c th nh gi 1 cch gn ng : + + 6 5h h hh5: chnh gia mt cht lng trn b chn ng chy chuyn vi mt b chn .Theo cng thc (4-15)[1] ta c :02 / 3515 , 0 FLQhL

,_

H s Foc tra theo biu H 4.23 [1].Vi 5 , 2LQL=2,5672,6 288339,8=0,0246L/D=0,68 th F0 =1,04Thay s ta c : h5=0,15.3 / 2672,6 288339,8

,_

.1,04= 8,77 cmLy h1 = 2,5 cm, theo bng 4/2 [1] th vi chp s 6, chiu cao ng hi : h6 = 8,25 (cm ) = 3cm Khi h = 8,87+8,25+3=20,12 cm Vih =20,12 cm ,Ql/L= 215 , h1 = 2,5 cm , =0,37 thi=3,8 mm = 3,8.20=76mm >25mm Nh vy vic la chn a 2 dng 1 bc khng ph hp .Ta s dng a 4 dng 1 bc:.

Hng dng lng trn mt a i vi a 4 dng 1 bc, lp lng trn mt a c chia lm 4 vng 1-2, 2-3, 3-4, 4-5. Mi vng c 9 hay 10 dy. Do 2 a lin tip c s ng chy chuyn l khc nhau nn gradien mt lng cc vng cng khc nhau.Ta c qui tc sau :1-2=4-5,2-3 =3-4Q2= Q3 = Q4 = 2Q1 = 2Q5S2= S3 = S4 = 2S1 = 2S5S1=2% A L1/D = 0,42 L1 = 543 cm S2=4% A L2/D = 0,52 L2 = 672 cm S3=4% A S3= 36768 cm2 Theo hnh 4.30 [1] th ng chy chuyn giachim 4% din tch a hay bng 36768 cm2 .Do vy b rng ng chy chuyn28,5 cm III.TNH CHIU CAO THP: p dng cng thc tnh chiu cao thp :H=( N- 2).h + 2a + bTrong H: chiu cao thpN: s a thc t ca thp h: khong cch gia hai a l 0,8m a:chiu cao nh thp ti a trn cng (3m)b:khong cch gia 2 a tip liu (2m)Thay s ta c : H =(50-2).0,8+2.3+2 = 46m III.GRADIEN MT LNG :1.Gradien mt lng quanh a :Vic tnh gradien mt lng c tnh nh biu 4.19[1]. Vi h5: chnh gia mt cht lng trn b chn ng chy chuyn vi mt b chn .Theo cng thc (4-15)[1] ta c :02 / 3515 , 0 FLQhL

,_

H s Foc tra theo biu H 4.23 [1].Vi 5 , 21LQL=2,5543 /4 288339,8=0,01L1/D=0,42 F0 = 1,0Thay s ta c : h5=0,15.3 / 2543 288339,8/4

,_

.1,0= 3,9cmLy h1 = 2,5 cm, theo bng 4/2 [1] th vi chp s 6, chiu cao ng hi : h6 = 8,25 (cm )V ly= 2,3 Khi : dy trung bnh ca lp lng trn mt a : 3,9+8,25+2,3=14,45 cmi= 1,8mm Chng ta cn tnh n nh hng ca dng hi nh hnh 4.20[1]i lngv ou = .0,84 1313154,762,95.106. 00395 , 0= 3,6 Theo hnh 4.20 th h s iu chnhbng 0,96.vy Gradien mt lng ng vi 1 dy chp l 0,96.1,8=1,73mm , trong vng l 1,73.9= 15,57 mm2.Gradien mt lng vng trung tm a :L2= 672cm L2/D= 0,52 Theo cng thc (4-15)[1] ta c :02 / 3515 , 0 FLQhL

,_

H s Foc tra theo biu H 4.23 [1].Vi 5 , 22 LQL=2,5672 /4 288339,8=0,0062L1/D=0,42 F0 = 1,015Thay s ta c : h5=0,15.3 / 2672 288339,8/4

,_

.1,015= 3,4cmLy h1 = 2,5 cm, theo bng 4/2 [1] th vi chp s 6, chiu cao ng hi : h6 = 8,25 (cm )V ly= 3,2Khi : dy trung bnh ca lp lng trn mt a : 3,4+8,25+3,2=14,85 cmi= 1,7mm Chng ta cn tnh n nh hng ca dng hi nh hnh 4.20[1]i lngv ou = .0,84 1313154,762,95.106. 00395 , 0= 3,6 ,22LQL=107 Theo hnh 4.20 th h s iu chnhbng 0,95.vy Gradien mt lng ng vi 1 dy chp l 0,95.1,7=1,62mm , trong vng l 1,62.9= 14,54 mmIV.TNH P SUT A:H thng ng hi chp cng nh s tn ti ca lp lng trn mt a to ra 1 tr lc i vi dng hi i qua a .Do p sut pha trn a phi b hn p sut pha di a, ngha l mi a gy ra 1 gim p sut. Ta gi ngn gn l p sut a.p sut a b gy ra bi lp cht lng trn a, bi gim p khi dng hi i qua h thng ng hi-chp v bi sc cng b mt. Trong nhiu trng hp c th b qua gim p gy bi sc cng b mt. gim p gy bi s chui lun ca dng hi qua h thng ng hi-chp ho c th tnh theo cng thc (4-11) [1]20

,_

,_

ovv LvoAQk h H s ko c gi tr ph thuc t s tit din hnh vnh khn so vi ng hi. Theo bng 4/2 [1]:Tit din hnh vnh khn =90,30 (cm2 ) Tit din ng hi = 76,00 (cm2 )tit din vnh khn/tit din ng hi = 90,30/76,00 = 1,19Theo H 4.22 [1] th ko = 0,00145Vy 262357 . 7610 . 95 , 6295 , 3 6 , 62595 , 300145 , 0

,_

,_

oh= 1,138cm Theo cng thc (4-13) [1] th gim p hl gy ra bi lp lng hot ng trn a phi bng chiu cao lp lng t mt lp lng n v tr thp nht khe chp m dng hi chui qua :hl = h3+ h4 + h5 +/2 = 0,9H + (h6 h1 h2 H) + h5 +/2= 0,9.3,81 + (8,25 - 2,5 - 0,65 - 3,81) +3,4 + 3,2/2 =11,03(cm)Vy theo (4-14) [1] :h = ho + hl = 1,138+11,03=12,169 cm Vy p sut a tnh theo chiu cao ct lng tng ng l 12,169cm V.NG CHY CHUYN :1. ng chy chuyn trung tm(3)TheoH 4.5 v cng thc (4-16) [1] th chiucaoca lpcht lng trong ng chy chuyn l: hc = (h6 + h5 + D) + h + hkhk l gim p gy ra bi s chy ca cht lng t chn ng chy chuynquakhe ng chy chuyn trn qua mt a.C th tnh hk theo cng thc (4-16a) [1] : 2210 . 65 , 1

,_

kLkAQhAk l tit din khe ng chy chuyn , Ak = L.hkKhengchy chuynphinhsaochompdicatmchnphingp tronglplngtrnmta1khongsungnkhngchodnghita di chui qua ng chy chuynln a trn. ng thi khe ng chy chuyn phi ln tcchy cadnglngtrongngchychuynraadil va phi,trnhgy hin tng dn .ngp lt .Nh vy cao khe phi nh hn mc cht lng trn a:'kh< + + 6 5h h h= 15 t 1Ly hk = 15 cmAk = L.hk= .1293,4.15= 19401 cm2224 . 194018 , 28833910 . 65 , 1 ,_

kh = 0,228 cm < 25mm Vy thay s vo ta c:hc= 14,85+12,169+0,228= 27,247 cm Thi gian lu cht lng trong ng trung tm l :t= Lc Qh A . 04 , 0 .= 288339,8/47 0,04.27,24 1313154,7.= 16,8s Tc chy xung ca cht lng trong ng chy chuyn l 27,247/16,8=1,62 cm/sKt qur tnh cho thy kch thc ng chy chuyn l hon ton thch hp 2.ng chy chuyn ngoi cng:Ak= 543.15=8145cm2hk= 1,65.10-228145 . 88 , 288339

,_

= 0,32cmhc =14,85+12,169+0,32=27,39 cm t =8 / 8 , 28833939 , 27 . 02 , 0 . 7 , 1313154= 17,7 s Tc chy xung ca cht lng trong ng chy chuyn l 27,39/17,7=1,54 cm/s.VI.HIN TNG NGP LT :Hintngngplt(flooding)l hintng trnngpchtlngtrongtonb khng gian gia cc a. Khi b ngp lt, thp chng ct b tc dn ti ngng hot ng vcht lngkhngchy kp,hikhng bay lnc.Ngoira,ncnc thgyn thpchngct dostngpsutqu mc(dn, tchtqu nhiu pha hi).Hintngngpltxy radochtlngtrongngchy chuynkhngchy kp hocdochtlngtrnmtablicunquddiditcngcadng hibay lnvitc quln.Nichunglsphnbkhnghplvng cha chp v vng ng chy chuyn.Dotchicahintngngp,ltchngtaphixemxt,nhgikhnngkhng b ngpngp lt. Ta c th nh gi kh nng theo cng thc (4-19) [1] .2222118 , 1 2 , 1

,_

+

,_

ll lSSSSfS1l: din tch l thuyt ca vng cha cc chpS1: din tch thc ca vng cha cc chpS2l: din tch ca vng ng chy chuynS2: din tch thc ca vng cha ng chy chuynf: i lng nh gi kh nng khng b ngp ltyu cu f < 1,2Theo cng thc (4-20) [1] :( )v v L lvlKQS /1Chn khong cch gia cc a l T =80 (cm) Theo biu H.4.24 [1]th K1 =250Do ( ) 95 , 3 / 95 , 3 6 , 625 250226613,91lS= 72,25 m2Theo cng thc (4-21) [1]:S2l = K2.(QL + eS1)Trong :K2: h s tra theo biu hnh 4.26 [1]Vi L - V = 621,65 kg/m3 ; T = 80 cm th K2= 0,15e : lng lng b li cun t 1 m2 mt a trong 1 pht v c tnh theobiu H 4.25 [1].Ta c:S1 = 70% A = 0,7.1313154,7 =919208,3 cm2lS1 /s1 = 0,79 e =0,0101S2l = 0,15.(288339,8+0,0101.91,9208)=43251 m2. Vy thay s ta c :2 292 , 91 . 8 , 192 , 9125 , 72 . 2 , 125 , 72

,_

+ ,_

f =1,003f< 1,2. Nh vy khng sy ra hin tng ngp lt trong thp .v thit k thp nh vy l hp l .