Công Nghệ Hóa Dầu

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B CNG THNGTRNG I HC CNG NGHIP TP.HCMKHOA CNG NGH HA*****

BI TIU LUN MN: CNG NGH LC DU

GVHD: NGUYN HU SN TP. HCM, THNG 10 NM 2012

MC LCI)craking nhit11)tng quan12)c s l thuyt1a)S bin i paraffin1b)Bin i ca olefin1c)Bin i ca naphten1d)Bin i ca hydrocacbon thm1e)S bin i ca hp cht lu hunh13)qu trnh craking nhit1a)Nguyn liu1b)Sn phm ca qu trnh cracking nhit14)cc yu t nh hng v s cng ngh1a)Cc yu t nh hng1b)S cng ngh v hot ng ca qa trnh cracking nhit1II)cc ha (coking)11)gii thiu qu trnh cc ha1a)Mc ch1b)Khi nim12)phn loi1a)Cc ho gin on.1b)Cc ha chm1c)Qa trnh cc ha tip xc1d)Cc ha tng si13)cc yu t nh hng1a)Nhit :1b)p sut1III)cracking hi (pyroly)11)Mc ch qu trnh12)c im qu trnh13)Lng hi nc14)Nguyn liu15)C ch to thnh sn phm chnh16)C ch to thnh sn phm ph17)S hnh thnh cc hydrocarbure acetylenique v allenique18)S hnh thnh hydrocarbure aromatique19)S hnh thnh cc hydruacarbure nng110)Sn phm (vi nghim ngt = 0.52 )111)Tiu th nng lng1IV)vis-breaking11)Tng quan12)Nguyn liu13)Sn phm14)Cng ngh visbreaking15)Cc yu t nh hng1a)Nguyn liu1b)Nhit 16)Cc s cng ngh in hnh1

cc qu trnh ch bin nhit trong ch bin du mcraking nhittng quanTrong cng nghip ch bin du kh, cc qu trnh ch bin thun ty bi nhit c p dng t lu nhm ch bin cc phn on du khc nhau thnh cc sn phm lng (xng, FO), kh v cc. Cc sn phm kh c cha nhiu olefin rt thch hp cho cng ngh tng hp ho du v ho hc.Mc ch chnh ca qu trnh cracking ni chung nhm to ra xng co ch s octance cao v mt s phn on khc nn ngy nay c nhiu phng php khc cho nng sut sn phm cao vd:cracking xc tc,reforming, isomer ha, ankyl haTuy nhin phng php cracking nhit vn c s dng rng ri trong nh my lc du.QutrnhNguynliuSnphmchnhNhit,oCpsut,kg/cm3

CrackinghiEtanAxetylen100014000,20,5

CrackinghiEtanEtylen8008500,22

CrackinghiPropanbutanEtylenpropan7708000,22

CrackinghiXngnhEtylenpropylen7207700,52

CrackinghiGasoilnhEtylenpropylen720-7500,52

CrackingnhitGasoilnhXng4695102070

CchoCnnngCc480530110

VibrekingCnnngGimtcnht440-4802070

Cracking nhit l qu trnh phn hy di tc dng ca nhit, thc hin iu kin nhit khong 470 n 540oC, p sut 20 n 70 at.Nguyn liu s dng t phn gasoil n cn nng ca du, ph bin hay s dng l cn mazut. Sn phm thu c bao gm kh cha nhiu olefin v xng.Ty theo mc ch thu sn phm, nguyn liu s dng v ch cng ngh m qu trnh c th chia cc qu trinh chuyn ha ha hc di tc dng ca nhit nh sau: Qu trnh cracking nhit Qu trnh nhit phn (pyrly) Qu trnh cc ha Qu trnh visbreakingy l cc qu trnh bin i nguyn liu du m di tc dng ca nhit cao thnh cc sn phm rn, lng, kh. Thnh phn v s lng cng nh cht lng ca sn phm cui c quyt nh bi cc thng s cng ngheejcuar qu trnh nh:nhit , p sut, thi gian phn ng.Trong qu trnh ch bin nhit kh cu trc c hai vn quan trng cn gii quyt: Ngn nga s to thnh cc trong ng phn ng hay trong cc thit b trao i nhit. m bo hiu qu s dng cao cc thit b trong dy truyn.Nh vy trong nhng qu trnh chuyn ha ha hc di tc dng ca nhit trn th qu trnh cracking nhit chim mt v tr tng i quan trng trong cng ngh lc du.c s l thuytBn cht ca cracking l s b gy mch cacbon, thu c nhng phn t mch cabon ngn hn ph hp vi yu cu .L phn ng thu nhit,nn i hi iu kin nhit thch hp.L qu trnh phc tp v nguyn liu gm s lng ln cc cu t ring bit, di nhit cao dn n s bin i rt phc tp nn kh theo diS bin i paraffinCnH2n+2CmH2m+ CpH2p+2Khi n 4 th lin kt C C bn hn C Hxy ra hin tng t lin kt C H to H2.Nhit cao, p thpnhiu sn phm kh.Nhit va phi (450 530oC), p sut caot gia mchnhiu sn phm lng.C ch: Theo Rice n xy ra theo c ch gc t do:

Nh vy, cracking nhit to ra mt lng ln etylen, sn phm thu c t nhnh, khng nhiu phn ng ng phn ha, kh thu c sn phm vng, v vy m xng thu c t qu trnh cracking nhit c tr s octan thp.Bin i ca olefinNhit thp, p sut cao olefin d trng hp. Nhit tng phn ng phn hu tng. Ngoi ra,olefin cn tham gia phn ng ngng t, ankyl ho vi naphten to thnh nha v cc.Bin i ca naphtenu tin xy ra cc phn ng sau: Kh nhnh ankyl Kh hydro olefin vng Aromatic Phn hu naphten a vng n vng. Kh naphten n vng parafin + olefin / diolefin.To nhiu sn phm lng v no hn so vi nguyn liu v parafin.Bin i ca hydrocacbon thm nhit cao, theo quy lut sau: Kh nhnh ankyl. Ngng t vng cc (cacboit). Tc hi ca cc:+ Gim tc truyn nhit.+ Gim nng sut bm.+ Tng chi ph vn hnh.S bin i ca hp cht lu hunhCc hp cht lu hunh nm trong nguyn liu di dng mercaptan ni chung cc hp cht lu hunh c bn nhit km..v mt s bn nhit nh benzoliophen, khi phn hy to ra H2S. Khng mong mun nhng hp cht ny c trong sn phm.qu trnh craking nhitNguyn liu Phn don mazut ca chng ct kh quyn. Gasoil nng ca qu trnh cracking xc tc. Cn nng ca qu trnh lm sch (DAO).Sn phm ca qu trnh cracking nhitKhSn phm kh cha nhiu hydrocacbon olefin v cn c th cha H2S . kh cracking cn cha mt lng ln nhng hp cht khng no ch yu, cn ca qu trnh cracking nhit cn c s dng lm nhin liu t l. Mt s c nhp chung vi cn gurdon v nhng sn phm khc lm nguyn liu cho l hi v nguyn liu ban u cho qu trnh coking.XngKhc vi xng chng ct trc tip c hm lng parafin l ch yu, xng ca qu trnh cracking nhit cn cha c olefin trong olefin c 1 ni i hoc aren c cha nhnh olefin chim a phn. V vy xng cracking nhit tr s octan MON = 68-72 cao hn so vi xng ca qu trnh chng ct trc tip(MON=40-45). Thnh phn ca mt s loi xng(% trng lng):Loi xngOlefinArenNaphtenParafin

Xng chng ct trc tip122662

Xng cracking nhit t mazut25-3512-15-840-45

Xng cracking nhit t gasoil40-4518-2015-2020-25

Xng Reforming nhit19-2014-1627-3233-37

Trong thnh phn ca du m khng cha olefin chnh v th nn xng i t qu trnh chng ct kh quyn s khng c thnh phn ca olefin. i vi xng i t qu trnh cracking nhit t gasoil c thnh phn olefin kh cao do gasoil ly t qu trnh cracking xc tc nn thnh phn olefin ca xng sau khi cracking nhit cao gp 2 ln so vi xng i t qu trnh cracking nhit t mazut.Xng cracking nhit cha nhiu olefin nn c bn km, di tc dng ca nh sng v nhit , cc phn t olefin d b ngng t, polymer ha, trng hp ha to nha. xng cha nhiu olefin d b bin i thnh mu sm. Xng cha nhiu olefin lm tng ch s octan nhng cng lm cht lng khng tt do cc olefin ny c cha lin kt linh ng nn d b chuyn ha (oxi ha) bi oxi khng kh (khi tn tr).Hm lng lu hunh trong xng cracking nhit cao dao ng trong khong 0.5 n 1.2 %.cc yu t nh hng v s cng nghCc yu t nh hngNhit Nhng thng s cng ngh quan trng nht nh hng n qu trnh cracking nhit l nhit , p sut v thi gian phn ng. khi tng nhit , tc cracking tng ln theo quy lut hm s m. Trong khong nhit chn trc, s thay i cc thng s v nhit v thi gian phn ng c tc dng tng h ln nhau. gi cho su bin i l nh nhau, khi tang nhit cn thit phi gim thi gian phn ng. i lng nhit phn ng l thng s rt quan trng. Khi tng nhit , tc phn ng phn hy tng ln v ngc li, khi gim nhit tc phn ng trng hp li tng ln. Gim nhit cracking s lm gim tc ca phn ng a t. Nh vy, tng hiu sut cc sn phm phn hy (kh, lng) v gim hiu sut cc sn phm a t (cn nha cc) cn thit phi gi nhit phn ng cao ng vi thi gian phn ng thch hp. l nhim v chnh ca qu trnh cracking nhit; cn i vi qu trnh cc ha, y sn phm chnh l cc, th qu trnh c hiu sut tt ch khi nht phn ng nm trong khong va phi.p sutp sut xc nh trng thi pha ca h cng nh chiu hng v tc phn ng. p sut khi cracking phn on gasoil nh cn phi m bo trng thi lng ca cc tc nhn phn ng, bi v trng thi lng to iu kin tt cho qu trnh trao i nhit, khng xy ra s qu nhit cc b, s to cc l cc tiu, cn hiu sut xng l cc i. Nu cracking cn nng, cn phi gi cho h thng trng thi pha hn hp hi-lng. Khi cracking xy ra trong pha lng vi nguyn liu nng nh mazut, gudron th p sut khng nh hng nhiu. Khi p sut v nhit cng cao, v tr t mch nghing v cui mch, iu dn n lm tng hiu sut sn phm kh, sn phm lng gim. Cn nu ch c p sut cao th v tr t mch C - C xy ra gia mch, dn n hiu sut sn phm lng tng.Nhit cng cao, p sut cng thp th pha kh s cng nhiu, tc dng trong l ng cng ln v cho php gim s lng ng cc trong cc ng xon ca l. Nhng trong qu trnh vibreaking, nh hng ca p sut khng ln, tng p sut ch c th lm tng mt cht t nng sut ca thit b. p sut cao thng lm tng nng ca cc tc nhn phn ng trongpha hi, iu s to iu kin cho cc phn ng kt hp nh phn ng polymer ha, alkyl ha v hydro ha.Nguyn liuNguyn liu ca cracking nhit ph bin nht l phn on mazt ca chng ct trc tip, phn on gasoil nng ca qu trnh cracking xc tc hay cn nng ca qu trnh lm sch. Cht lng ca nguyn liu l mt thng s quan trng xc nh cht lng sn phm. khi iu kin cracking khng thay i, nu ta dung nguyn liu c thnh pn khc nhau s cho cc kt qu khc nhau. Khi tng gii hn nhit si ca nguyn liu, tc phn ng cng tng ln:Nguyn liuGii hn si, oCHiu sut xng, %kh.l

Phn on ligroil180 22012.1

Phn on Kerosen220 27014.9

Phn don gasoil270 30015.8

Phn on xola300 35018.0

Thi gian luThi gian lu cu nguyn liu l thi gian nguyn liu trong vng phn ng. Nu thi gian lu ngn, nhiu phn t cha kp thc hin phn ng dy chuyn, v cha b cracking nn cha phn hy, lm cho hiu sut qu trnh thp. Ngc li, nu thi gian lu cng di, sn phm to thnh cng c nhiu c hi tng tc vi nhau nn d dng b ngng t (cc olefin), dn n to nha, to cc. Nh vy, tng hiu sut sn phm kh, xng, v gim hiu sut phn ng trng hp (cn, cc) th vng phn ng, nhit duy tr cao vi thi gian lu ca nguyn liu trong vng phn ng phi thch hp.S cng ngh v hot ng ca qa trnh cracking nhit

Cc thit b chnh ca dy chuyn:L t (1 v 2)Trong dy chuyn cracking nhit ngi ta hay dng l ng hai bc: bc x-i lu loi bung. s cu trc ca l gm hai bung bc x v mt bung i lu. Trong bung bc x, nhin liu c t chy cp nhit cho l. Ngi ta b tr cc ng pha trn v di ngn la trc tip nhn bc x, cn bung i lu l nhn nhit ca kh khi ch yu do truyn nhit i lu. Trong bung bc x, pha trn pha-ken ca ngn la, ngi ta b tr khong 6 ng vi ng kinh 127x10mm, pha di ngn la ngi ta b tr khong 30 ng. trong buongf i lu c 84 ng. b mt t nng tng cng l 900m2 . t, ngi ta b tr 18 vi t dc theo chiu di ca bung bc x, c np nhin lu kh hoc lng.Thit b bay hiHn hp sn phm bay hi t bung phn ng sang thit b bay hi p sut cao (55-100atm). phn chia pha trong thit b bay hi th phi duy tr p sut cao phn cn i ra y thit b bay hi cha mt lng ln phn on xng v gasoil ha tan ln. tch ring phn nh ny ngi ta cho bay hi p sut thp. Nh p sut thp, mt phn nh c bay hi ra khi phn cn. tng kh nng bay hi phn di thit b cho hi nc vo. Thit b ny bay hi p sut cao c cu to l hnh tr t 2-3m, chiu cao l 15-18m. Thit b bay hi p sut thp c trang b cc a chng ct. N khng nhng ch tch cc cu t nh ra khi cn craking m cn t nng nguyn liu do nhit lm lnh v ngng t hi cc phn on c tch ra.Ct tinh ct (8 v 9)Ct tinh ct l mt hnh tr thng ng c ch to bng thp cacbon pha ngoi, cn pha trong c lt bng thp mm, bn trong thp c b tr cc a v c chia lm hai phn bng mt a ic. phn pha trn lm nhim v chng luyn cn phn pha di ch chng ct cc cu t nh trong cn nng. v ngoi c cc lp cch nhit v cc ca kim tra s lm vic ca thp v lm v sinh, lp rp v thay th cc a khc. Khc vi ct tinh ct du th, thp tinh ct ny lm vic iu kin p sut cao (0.8 1.0 MPa).Hot ngNguyn liu l phn du nng c bm 13 cho qua thit b trao i nhit 11, vo phn bn di ca thp tinh ct 8, ng thi cho v phn nh ca thit b bay hi p sut thp 9. T thit b 9, nguyn liu c trn vi phn on gasoil nng v c a vo y thp 8, dng nguyn liu v phn tun hon c trn vi nhau ri nh bm 18 cho qua l t nguyn liu nng 1, sau vo bung phn ng 3. Phn on gasoil thu c a ic ca thp 8 nh bm 19 cho qua l t 2 cracking su v tip tc vo thit b phn ng 3. T thit b 3, sn phm i vo thit b bay hi p sut cao 4, y phn nng cracking c tch ra v c cho vo y thp bay hi p sut thp 9, t thit b ny s tch ra c phn on gasoil. Phn nng c ngng t v cho quay li tun hon cng vi nguyn liu, cn phn nh c cho qua thit bj trao i nhit sau i ra khi dy chuyn.Dng hi t nh thit b 4 c cho vo thp 8, t nh thp 8 tch ra phn kh v xng, sau c lm lnh cc thit b 5, ri c tch trong thit b tch kh 6. Kh tch ra c dn n dy chuyn phn tch kh, cn xng c cho vo ct n nh xng, cui cng vo b cha xng.

Cc thng s cng nghNhit oCp sutMPa

L t 1Vo400 410 4.0 5.5

Ra450 490 2.2 2.7

L t 2Vo380 390 4.0 4.5

Ra 540 550 2.2 2.8

L phn ng 3470 5001.5 2.5

Thit b bay hi p sut cao 4

nh thp415 430

y thp410 420

Thp tinh ct 80.8 1.2

nh thp190 210

Gia thp275 320

y thp380 410

Thp bay hi p sut thp 90.15 0.35

nh thp190 195

Gia thp290 310

y thp380 410

Trn th gii ph bn hn nay l cc dy chuyn cracking vi cng sut t 600 ngn tn/nm n 1800 ngn tn/nm theo nguyn liu. cn vi dy chuyn vis-breaking th cng sut thng cao hn, t 800 ngn tn/nm n 2000 ngn tn/nm.cc ha (coking)0. gii thiu qu trnh cc haMc chQa trnh cc ho nhm sn xut cc cc t du m t cc nguyn liu l cn nng nh gudron ,cn ca qu trnh cracking nhit hay cracking xc tc . Qa trnh ny c tin hnh iu kin nhit t 450-520 oC . Sn phm chnh l cc ,c dng cho cng nghip luyn nhm , ch to in cc , cho nghnh cng nghip khc nh cng ngh in t , vin thng. Ngoi ra ta cng thu c cc sn phm khc nh kh ,xng v gasoil cc ho.Khi nim Qa trnh cc ho l mt dng ca qu trnh cracking nhit .S to thnh cc l do cc phn ng ngng t cc hydrocacbon to thnh cc hp cht cao phn t c ngng t vng thm cao . Nh vy nu nh nguyn liu cha nhiu vng no , nhiu vng thm ngng t c mch bn di ,l cc cu t d tham gia phn ng ngng t , s cho hiu sut v cht lng cc tt nht .Kh nng to cc v hiu sut c nh gi thong qua i lng gi l cc ho Conradson. cc ho ca nguyn liu cng cao cng cho php nhn nhiu cc hn.0. phn loiTrong thc t ,cc dy chuyn cng ngh cc ho c phn loi thnh cc ho gin on , cc ho bn lin tc (cc ho chm) v cc ho lin tc trong lp si ca cc ht cc.Cc ho gin on.Cc ha gin on l loi c in v n gin nht. Dy chuyn gm 1 thit b chnh l ni cc ha, hnh tr c t nm ngang, ng knh t 2-4m v chiu di 10-12m. Nguyn liu c cho vo ni ri c t trc tip nhm nng nhit , tch phn nh v to cc. Khi t ti 450-460oC, sau gim nhit tch phn nh. Sau tip tc gia nhit t 700-750oC. Khi thy nhit gim th ngng gia nhit v duy tr thm thi gian na hon thnh to cc. Sau c lm lnh n 250oC v tho cc. Chu k lm vic khong 25-35h. Nng sut ti a khong 5 tn.Cc ha chm*Mt s h thng s cc ha chm.Hnh 1.1:

Hnh1.2:

*y l cng ngh kh ph bin v rng ri trn th gii. Loi cng ngh ny phi c t nht 2 bung phn ng(bung cc ha), mt bung lm nhim v phn ng cn bung kia trong thi gian tho d cc, sau li thay th cho nhau. Nguyn liu c t nng lin tc trong l ng n nhit 480-520oC; p sut t 2kg/cm2 ri c np vo bung cc ha. Nguyn liu c gi trong bung cc ha vi thi gian tch hi hydrocacbon nh v to cc. Khi bung ny np th chuyn sang bung khc. S hot ng theo kiu bn lin tc.c m t chi tit trong s sau: Nguyn liu c chia lm 2 dng, nh bm bm qua cc thit b trao i nhit a vo l ng 1 ri t a vo ct tinh ct. Ti y nguyn liu c tip xc vi sn phm hi kh t bung cc ha sang vi nhit khong 425oC, nguyn liu c t nng ti 400oC. Sn phm nng v phn tun hon c trn cng vi nguyn liu mi to thnh nguyn liu cho vo bung cc ha. T y ct 3, nguyn liu c bm qua l ng 2 nng nhit ln 510oC v tip tc c np vo bung cc ha 4 ang sn sng lm vic (trong chu k np liu). Cc bun khc ang tho cc hoc ang tho d cc. Gasoil nng t y ca ct tch c bm qua l t 1, y n c t n nhit 510 520oC, qua van trn vi nguyn liu cc ha v c np vo bung cc ha. Ti nh ct 3, kh v hi xng cng vi hi nc c cho qua thit b lm lnh bng khng kh, tip theo lm lnh bng nc thit b 8 ti 40oC sau a ti thit b tch kh 9. Nc t y thit b tch kh c cho vo b 10, t bm qua cc thit b trao i nhit n 150oC ri vo l 1 v 2. Gasoil nh t ct tch hi 11 c bm qua thit b trao i nhit, sau qua thit b lm lnh ri ra khi dy chuyn thnh sn phm. Phn gasoil nng t y ct 11 c bm qua thit bj trao i nhit, vo thit b un nng cp nhit cho y thp n nh ri cng c cho qua thit b t sn xut hi nc vi p sut t 1 1.4 MPa, sau c lm lnh trong thit b ngng t ri a ra khi dy chuyn. Kh bo(C3 C4) t thit b phn tch kh 12 cng c a ra ngoi lm sn phm. Xng cha n inh c bm phn ln, a vo thit b trao i nhit sau cho vo ct n nh 13. Di p sut 0.6 MPa, qu trnh kh butan c thc hin. Hi t thit b 13 c a qua thit b lm lnh, sau c a i phn tch kh 17 nhn C1,C2 . Xng n nh thit b 13 c cho qua thit b trao i nhit, thit b lm lnh ri a vo b cha. Khi tho d cc, thit b c lm lnh bng hi nc n 400oC. Hi tch ra c da vo thp tch 3, sau lm lnh bng khng kh v bng nc ri a vo b cha 16 tch hydrocacbon nng. Cc trong bung c tho bng phng php thy lc, nc tch ra c a vo thit b lng lc 16 v c a tr li chu trnh.*Bng 1:Ch cc ha chm Nga v M Nguyn liu

Thng sNgaM

Cn crackingCn du m

GudronDu Ty XibiaCaliforniaTrung ngCraking nhit

T trng 0.95401.0400.98610.9841.083

Hm lng S,%0.512.41.60.380.56

cc ho8.021.09.611.38.6

Hiu sut sn phmKhXngGasoil nhGasoil nngCciu kin lm vic Nhit ra khi l t 0 oCp sut trong bung cc ,MPa

9.110.424.737.818.0

487

0.185.03.029.227.835.0

505

0.412.015.735.215.521.6

496

0.416.516.056.5

21.0

488

0.2 18.10.921.1

59.9

502

0.34

Qa trnh cc ha tip xcQa trnh ny c m phng bng s cng ngh sau

Hnh 2: S cng ngh cc ha tip xc

Nguyn liu c t nng trong thit b trao i nhit 10 ,c trn vi phn tun hon t thp chng ct 13 ,ri bm qua l ng 9 .Nhit t nng trong l t n 400 oC .Hn hp nguyn liu sau khi ra khi l t c cho vo l phn ng 1 tin hnh cc ha , ngi ta np lin tc cht ti nhit l cc ht cc c nhit 540-580 oC , kch thc ht t 3-12mm vo bung phn ng .Do tip xc vi cc ht cc nhit cao , nguyn liu s tham gia phn ng cracking ,cc ha. Cc to thnh bm vo ht cc mang nhit lm cho kch thc ca chng tng ln . Thi gian lu ca cc ht cc trong thit b phn ng ph thuc vo nhit ,p sut trong thit b v thng c t 6-10 pht , khi p sut trong thit b l 1,5 at v nhit 510-520 o C. Cc chuyn ng xung ng dn 4 ,ri cho qua phn loi 6 tch cc ht c kch thc ln hn 12mm ,sau cho qua thit b lm ngui 8 ri ra ngoi lm sn phm. Cc c kch thc ht nh c cho qua l t 7 nng nhit ri a vo trong bunke 2 . Sn phm hi c cho qua thit b trao i nhit 12 , vo ct tinh ct 13 v qua cc ct ti bc hi 16,17,18 phn tch thnh cc sn phm : Kh ,xng, gasoil nh, gasoil nng v cn . Cn c cho tun hon li chu trnh.*Bng 2: Nng sut qu trnh cc ha tip xcNng sutNguyn liuHiu sut sn phm %kh.I

T trng cckhXng

Gasoil

Cn

16 tn cc / ngy1.10111919.816.253.519.5

70 tn cc/ ngy1.055

24

11.4

12.5

49.6

36.5

900 nghn tn cc/nm1.0282014.620.043.022.4

Cc ha tng siHinh 3: s cng ngh cc ha tng si (lp si)I: nguyn liu, II: xng v kh, III: Gasoil nh,IV: Gasoil nngCng ngh cc ha lp si p dng qu trnh lp si ca cc ht cc c nhit cao khong 480-540oC trong l phn ng S thit b: Nguyn liu i vo oc chia lm 2 phn, mt phn vo thit b phn ng, mt phn vo thp ra, cc trng thi tng si c nhit cao t l t sang. Trong thit b phn ng xy ra cc phn ng cracking nhit v cc ha. Hn hp kh, xng, gasoil t thit b phn ng vo cyclon tch nhng ht mn v hn hp hi i ln thp ra ra cc ht bi cha tch c cyclon (thp ra ngc chiu tng hiu sut chuyn ha). Sau hn hp hi c a vo thp chng ct. nh thp chng ct thu c xng v kh; y thu c gasoil nng v gia thu c gasoil nh. Cc t thit b phn ng c a qua l t ( trng thi tng si) nng ln nhit 600 620oC. Cc ht ln c cho qua thit b tch, lm ngui v a ra ngoi. Cc mn bay ln theo gp O2 t my nn kh cung cp nhit cao cho thit b phn ng. Nhit khi l t cao tn dng nhit sinh cng.Qa trnh cc ha cc si thng t c nng sut rt cao . Cc ha tng si c nhiu u im so vi cc ha chm hay cc ha gin on do vi trng thi tng si trnh c hin tng qua nhit cc b.0. cc yu t nh hngNhit : Qu trnh tin hnh nhit cao: 400-450oC (c ti liu ghi 400-520oC) Nhng khng c qu cao v s lm cho xut hin nhiu sn phm phn hy (kh v lng) v sn phm chnh ca chng ta l sn phm a t (cc).p sut p sut th ln hn hoc bng vi p sut kh quyn. Khng c tin hnh p sut qu cao v s xut hin nhiu kh lm th tch tng ln chng li qu trnh ca chng ta l ngng t-gim th tch. y l yu t quan trng nht nh hng n qu trnh cc ha.cracking hi (pyroly)0. Mc ch qu trnh Sn xut mt lng ln nguyn liu cho cng nghip ha du: ethylene v propylen, ngoi ra cn butadiene v benzenec im qu trnh L qu trnh cracking nhit cc hydrocacbon paraffine vi s c mt ca hi nc Phn ng thu nhit mnh. Sn phm chnh l hn hp kh gm cc cu t c hot tnh cao (olefin), xng v du nng. Sn phm ph gm cc hp cht thm a vng V vy cn phi lm sch n hm lng ppm. nghim ngt c c trng bi t l C3H6/C2H4 T l C3H6/C2H4 nh : nghim ngt cao i hi nhit ln => u tin sn xut EthyleneLng hi nc H = lng hi nc / lng nguyn liu (m/m) H thay i theo phn t lng nguyn liu: Ethane : H = 0.25 0.4 Naphta : H = 0.5 0.8 Gasoil : H = 0.8 1 Tng ng vi p sut u ra ng phn ng l 1.04 bar ( trnh khng kh lt vo )Nguyn liuNAPHTA

NhTrung BnhNng

T trngng cong chng ctPIPFThnh phnn-Pi-PNAr

0C0C

%m%m%m%m0.65

3590

5239720.68

44125

46311850.71

60175

3229318

BUTHANE

C3n-Buthanei-ButhaneButhane%m%m%m%m2582713

Mt s ngun nguyn liu khc: Ethane, Propane, Kerosene, Gasoil, du th...C ch to thnh sn phm chnhNguyn liu l C2H6:Khi mo:Lan truyn:

t mch:

C ch to thnh sn phm phCc dng phn ng ph c bn: Nhit phn cc olefin sinh ra. Hydro ha v d hydro ha cc olefin sinh ra, to thnh parafin, diolefin, v cc acetylenique. Polime ha. To vng v ngng t.S hnh thnh cc hydrac, etyleniquallenique

S hnh thnh hydrocarbure aromatique

S hnh thnh cc hydruacarbure nng

Sn phm (vi nghim ngt = 0.52 )NAPHTANaphta trung bnh + Buthane (75:25) (%m)

%mNhTrung bnhNng

C2C2H4C3H6Coupe C4ButadieneCoupe C5+BenzeneHuite2034189.54.51761.517321794.522.582.517291594.5261041831.517.5114.52072

Tiu th nng lng( Nguyn liu : Naphta trung bnh )T l C3=/C2=

ThpTrung bnhcao

Hi ncFuel gasinCh s nng lng tiu th/TC2H4/T nguyn liu-2 0006 7001

6 6001 760-2 0506 4000.94

6 3251 850-1 9506 2000.88

6 1001 900

vis-breaking0. Tng quanVisbreaking l mt qu trnh s dng nhit nhm chuyn ha cn ca qu trnh chng ct kh quyn (RA: residue atmospherique) hoc cn ca qu trnh chng ct chn khng (RSV: residue sous-vide) theo con ng cracking nhit thnh kh, xng, cc sn phm trung bnh v cn c lm gim nht. Cn RA v RSV c np liu vo thit b gim nht thng thng gim nht ca nhin liu (fuel oil) v tng hiu sut thu cc sn phm trung bnh trong nh my lc du.Qa trnh visbreaking thng b gy cc phn t gia mch nhit khong 4500C vi khong thi gian rt ngn.Cc phn t parafin mch di s b b gy thnh cc phn t mch ngn hn,phn ng dealkyl s gip b gy cc mch nhnh ca cc phn t hydrocacbon thm. i vi cc nh my lc du ngy nay nu ch bin du th nng hn v c nhu cu cao hn v sn phm th visbreaking cung cp kh nng chuyn ho chi ph thp m vn tng c sn lng kh ,xng v cc sn phm khc;ng thi lm gim nht ca sn phm nng FO.y cng l mc ch chnh ca qu trnh visbreaking.Mc tiu visbreaking: Gim nht ca dng ngun cp d liu: thng y l cn chng ct chn khng du th, nhng cng c th l d lng t hot ng hydroskimming, bitum t nhin t thm trong t hoc ct tar , v thm ch c mt s loi du c nht du th cao. Gim lng du nhin liu cn li c sn xut bi nh my lc: du nhin liu cn li thng c coi l mt sn phm c gi tr thp.Nhu cu nhin liu cn li tip tc gim khi n c thay th ti cc th trng truyn thng ca mnh, chng hn nh nhin liu cn thit to ra hi nc trongcc nh my in, sch hn t cc nhin liu thay th nhkh gas t nhin. Tng t l cc sn phm chng ct gia trong nh my lc du u ra: sn phm chng ct Trung c s dng nh mt dung mi vi cc loi du cn li mang li nht ca h xung n mt mc th trng.Bng cch gim nht ca dng d trong mt visbreaker, du nhin liu c th c thc hin bng cch s dng t cht pha long v cc sn phm chng ct trung lu c th c chuyn hng n diesel c gi tr cao hn, sn xut du si m.Nhng u im ca ca qu trnh l: Ct gim hm lng lu hunh trong nhin liu. Tng gi tr ca cc phn on trung bnh s dng lm nhin liu cho cc ng c diesel Gi thnh thp hn.Nguyn liu Cn ca qu trnh chng ct kh quyn (RA: residue atmosphrique) hoc cn ca qu trnh chng ct chn khng (RSV: residue sous-vide).Sn phmKh, xng, cc sn phm trung bnh v cn c lm gim nht.C cu sn phm theo ngun nguyn liu t cn du th RpSn phm%khi lng

Xng6

Gasoil15

LPG3

Tar76

Trc visbreakingSau visbreaking

nht 1000C(centistokes)930115

T trng(kg/l)1,0201,048

n nh ca sn phm theo chiu tng chuyn hoCng ngh visbreakingC hai loi cng ngh gim nht c th thng mi ha c: loi s dng l t (furnace) v qu trnh soaker. i vi cng ngh th nht, s chuyn ha t c bi s cracking nhit cao trong thi gian tng i ngn v c xc nh trc trong thit b gia nhit (heater). Cn trong qu trnh soaker, l qu trnh thc hin nhit thp vi thi gian lu ln, phn ln s chuyn ha xy ra trong mt bnh phn ng (reaction vessel) hoc trong mt ci trng (soaker drum) m ti hai dng lu th hai pha lm vic nhit thp hn v thi gian lu di hn.C hai phin bn ca qu trnh visbreaking khng s dng bt k cht xc tc.

S cng ngh soaker visbreakingTrong qu trnh vn hnh theo kiu l t, nguyn liu c np vo thit b gia nhit ca thit b gim nht (visbreaker heater), ti y nguyn liu c gia nhit n nhit cao, gy ra s ha hi mt phn v s cracking nh. Dng ra ca thit b ny c lm lnh vi dng gas oil hoc nhng nhng sn phm y ca thit b phn on lm ngng li cc phn ng cracking. Hn hp lng hi i vo thit b phn on phn tch thnh kh, xng, gas oil v cn gim nht (tar). nhng sn phm y sau c trn vi nhng nguyn liu nh hn (cutter stock) p ng cc tiu chun ca nhin liu trong cc l t. Gas oil t thit b ny thng c s dng lm cutter stock phi trn vi cn gim nht. Cc yu t nh hngNguyn liuS chuyn ho sn phm cn thnh sn phm nh hn b hn ch bi mt s c tnh nguyn liu, chng hn nh hm lng asphaltene, natri v hm lng carbon Conradson. Mt nguyn liu vi hm lng asphaltene cao s cho hiu sut chuyn ho thp. Ngoi ra ,s c mt ca natri cng nh hm lng cao Conradson carbon, c th tng t l to cc trong ng gia nhit. Gim thiu hm lng natri v Conradson carbon s ko di c chu trnh lm vic ca h thng.

Chiu di quy trnh , chuyn ho theo cht lng ngun nguyn liu

Nhit

Cc s cng ngh in hnh

Mt thit b cracking in hnh c th lm vic khi gim nht ca dng thu hi c yu cu v vy nhu cu thnh phn ct cht lng cao c th gim sn xut mt loi du thng mi t cn FO.Thit b visbreaking c nhp liu vi cn chng ct chn khng haykh quyn. Nhp liu dc nng ln n nhit thch hp trong heater. Phn ng c hco php din ra n chuyn ha yu cu trong soaker trong heater. Dng hi c thm vo cc ng gia nhit duy tr vn tc ti thiu cn thit v thi gian lu v ngn chn cc ha trong cc ng. Sau khi ra khi soaker, hn hp c lm ngui trung bnh dng cc phn ng v a n thit b phn tch phn loi. Hn hp nng c a vo phn tch, mt phn lng chy xung y thp, c tch bng hi nc sn xut sn phm y. Dng hi bay ln thp, ra condenser ngng t, sau i n b cha sn phm nh, ti y s tch ra kh, nc c nhiu lu hunh, v lng c a v hi lu mt phn, phn cn li i n thit b n nh. Ti mm x gia thit b tch, gas oil c ly ra, mt phn i qua thit b trao i nhit s b (hay to hi) ri hi lu ln pha trn cao hn, phn cn li vo stripper bng dng hi ri sau lm mt v thu gas oil hoc trn vi sn phm y t nht yu cu. Sn phm y c th i qua thit b gia nhit s b cho nhp liu tn dng nhit.

S ny ging vi s u tin ngoi tr sn phm y ca visbreaker c a n mt thp chn khng thu hi them cc sn phm chng ct. S ny c th c m t t lc cn nhp liu c chuyn i thnh nguyn liu cracking.Trong s ny, sn phm y c a n phn di thp bc hi chn khng. Phn lng i xung di y thp ni c dng hi nc tch. Phn hi bay ln v c ngng t tng phn thnh sn phm chng ct. Trong thit b ny, chng ta thy c hai mm x. mm thp hn, sn phm heavy vacuum gas oil c ly ra,tn dng nhit v mt phn hon lu, phn cn li gp chung vi light gas oil v dng hi lu ly ra mm trn to thnh dng gas oil chn khng. Sau khi visbreaking, nht ca FO gim t yu cu, c th dng lm nhp liu choc raking. Dng hi nh thp chn khng i n h thng bm chn khng ejector 3 lp. Hi ngng t v dng hi y c gom li ti thit b gom condensate.

Mt thit b cracking nhit c s dng vi mt visbreaker khi mun chuyn i ti a sn phm nh hay cn gim im chy cc i.

36