qua trinh cracking xuc tac 9904

8/2/2019 Qua Trinh Cracking Xuc Tac 9904

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Qu trnh Cracking xc tc (P1)

Qu trnh Cracking xc tc l qu trnh quan trong trong nh my lc du sn xut xng c ch

s octan cao t cc phn on nng hn. p ng yu cu cht lng sn phm ra.

1. Gii thiu chung:

2. C s l thuyt ca qu trnh2.1 Xc tc cho qu trnh CrackingXc tc cho qu trnh cracking tng si trong cng nghip thuc lai axit rn, c thnh phn khphc tp nh sau:Thnh phn xc tc cracking tng si trong cng nghip


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2.2 iu ch xc tc FCCQuy trnh sn xut xc tc FCC hin i c m t theo s sau (Grace-Davison):Hp phn zeolit Y:L Alumosilicat tinh th ngm nc vi cu trc kiu Faujazit vi l xp 3 chiu ng nht v c kchthc ca s ~ 8 .V thnh phn ha hc ca zeolt c biu din bng cng thc: M2/nO.Al2O3.x SiO2.y.H2O

y: x > 2 v n l ha tr ca cation kim lai MZeolit c to thnh t cc n v cu trcKhi cc n v cu trc c bn ni vi nhau theo cc mt 4 cnh ta c lai zeolit A, nu ni vi nhautheo cc mt 6 cnh ta c lai zeolit X hoc Y c cu trc tng tZeolit Y c th dng khong t nhin, nhng hin nay ch yu c tng hp t oxyt silic v oxytnhm, i khi t qu trnh tinh th ha t st nung (Qui trnh Engelhard).Dng Na-Zeolit c iu ch bng phng php kt tinh gel alumosilicat natri. Silicat Natri (Thuc khi x l oxyt silic vi dung dch xt nng) cho tc dng vi aluminat natri (thu c khi hatan oxyt nhm ngm nc trong dung dch hydroxyt natri)s to thnh hydrogel v nh hnh. Gelny sau s c tinh th ha trong iu kin kim sat nghim ngt to Zeolit(Alumosilicat tinh th) vi cc ion aluminat v silicat c xp xp theo cu trc nh.

Cu trc c bn ca Aluminosilicat v n v cu trc c bn ca zeolit.

Zeolit dng Faujazit c khung tinh th 3 chiu to thnh t cc t din SiO4 hoc AlO4. Lin kt -Si-O-Al- to thnh cc l xp b mt c ng knh c nh t cc hc, knh c kch thc 4-8. Cccation d dng c trao i v c a ra khi Zeolit. Cu to Faujazit c m t nh hnh:

Cc Zeolit Y c a vo xc tc FCC di cc dng khc nhau:

+ Trao i mt phn hoc han tan vi dt him, phn cn li c th decation to cc dng REHYhoc REY.+ Bin tnh bng phng php x l nhit v (hoc) x l ha hc to cc dng zeolit decation siu

bn: H-USY, RE-H-USY hoc dng dealumin: H-DY, RE-H-DY.


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Vai tr ca t him ch yu lm tng bn nhit cho tinh th (vi zeolit dng decation NH4Y, nhit > 500oC tinh th c th b ph hy nhng vi dng REY, nhit > 900oC vn bo tonc tnh cht tinh th.Mt lai zeolit mi hin nay thng c a thm vo xc tc FCC, l ZSM-5 nhm tng ch soctan ca xng v tng olefin. ZSM-5 c t l Si/Al = 50, kch thc l xp tng i nh (5.5),hn ch cc phn t c kch thc ln i qua, do khng lm xy ra cac phn ng cracking i

vi chng (Cc parafin mch nhnh, cc Alkyl benzen...) nh th khng lm gim cc hp phn choch s octan cao. Hn na n cn tng olefin, khng lm tng hm lng cc. Hin ti, 40% cccm FCC Ty u a ZSM-5 nh mt ph gia tng ch s octan.Hp phn pha nn (Matrix):Trong qu trnh sn xut cht xc tc, hp phn ny ng vai tr l cht pha lang v cht kt dnh.Cht pha lang phi l cht tr nh cao lanh,ng vai tr ti nhit, hn ch s qu nhit ca cctinh th zeolit trong qu trnh ti sinh, tng bn c hc ca cht xc tc, lm gim lng Na uc xc tc... cht kt dnh c th l cc gel ca oxyt xilic, cc polymer cha nhm, hp cht chat st, cng c th l alumosilicat v nh hnh. Cht kt dnh ng vai tr gn kt cc hp phntrong xc tc FCC, to tnh ng b vt l cho xc tc.Cc nh sn xut xc tc chia pha nn thnh 2 phn: Phn hat ng l cc alumosilicat v nhhnh, oxit nhm; phn khng hat ng l cc cht tr nh oxit silic, cao lanh. Pha hat ng c tnhaxit thp hn do c hat tnh xc tc v chn la thp hn so vi cc Zeolit. Oxit nhm c

hat tnh xc tc thp hn Al-Si v nh hnh, nhng ngi ta thng a vo trong trng hpcracking cc phn an nng. Vic a pha nn vo h iu chnh tnh axit ca xc tc v tngth, so vi cc zeolit hoc Al-Si v nh hnh ring l. c tnh ca xc tc FCC ph thuc ch yuvo 2 thnh phn Zeolit v pha nn hat ng. T l cc hp phn ny c xem xt thn trngtrong qu trnh sn xut nhm m bo cc nhu cu ring bit ca nh my lc du v hiu sut vcht lng sn phm.2.3 C ch hnh thnh trung tm hot ng trn b mt xc tcXc tc cho qu trnh Cracking l xc tc axt. Cc trung tm hot ng trn b mt cht xc tc lcc tm axit Bronsted v Lewis. Cc trung tm ny hnh thnh do trong mng tinh th ca xc tcny, bn nguyn t Oxi lin kt vi Nhm nn khng cn bng v hnh thnh mt in tch m. Ccion nh Na+, Mg2+ hay proton s trung ha in tch ny v hnh thnh tm axt Bronsted

Khi tin hnh x l nhit khong nhit 400 500oC th xut hin cc tm axt Lewis theo s sau:

2.4 Cc giai on phn ng cracking khi c mt cht xc tcS khc nhau c bn gia cracking nhit v cracking xc tc l phn ng cracking khi c mt chtxc tc xy ra theo nhng c ch nht nh v d khng ch. Do sn phm ca cracking xc tcs c tnh chn lc cao hn so vi cracking nhit.Cc giai on phn ng cracking khi c mt cht xc bao gm:Bc 1. Hp ph cc ion Hydride trn cc tm Lewis:


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Bc 2. Phn ng gia cc proton t Bronsted vi cc olefin:

Bc 3. Phn ng gia cc ion cacboni sinh ra t bc 1 v 2 vi cc hydrocacbon bng cch tora cc ion hydride

Cc ion hydride ny khng bn s b phn hy thnh cc mch ngn hn,v d nh:

Qu trnh b ry mch cc ion cacbonni tun theo mt s qui lut sau: Cc parafin mch di v ccolefin lun ng phn ho trc khi b cracking. S cracking thng xy ra gia mch v thc tkhng bao gi t hn 3 nguyn t C tnh t u mch. Cc nhnh ankyl gn trn vng thm s bct st vng v cc nhnh ankyl gn vng no s b ct v tr t 3 nguyn t C tr ln tnh t umch.2.5 C ch phn ng ho hc xy ra trong qu trnh cracking xc tcC ch phn ng cracking xc tc l c ch ion cacboni. Cc tm hat tnh l ion ccboni c tora khi cc phn t hydrocacbon ca nguyn liu tc dng vi tm axt ca xc tc.Tm axt xc tc c 2 lai: Lai Bronsted (H+) v Lewis (L).Tm Bronsted l khi tham gia phn ng c kh nng cho proton hot ng (H+) cn tm Lewis ththiu electron nn c xu hng nhn thm in t.Phn ng cracking xc tc sn ra theo cc giai an sau:- Giai an 1: to ion cacboni:V d: trong trng hp i vi cc hydrocacbon mch thng (Alcan):

Trng hp phn hy izo-propyl-benzen: Trn tm axt kiu xc tc Lewis:

Trn tm axt kiu xc tc Bronsted:

- Giai an 2: Cc phn ng ca ion cacboni to cc sn phm:Khi cc ion cacboni c tao ra s lp tc tham gia vo cc phn ng bin i khc nhPhn ng ng phn ha:


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Phn ng ct mch theo quy tc (ct mch v tr so vi ccbon mang in tch)

Cc ion tip tc tham gia cc phn ng ng phn ha, ct mch tip,alkyl ha hay ngng t. Binn cc ion cacboni tip din cho n khi c cu trc bn vng nht. bn ca cc ion cacboni c th xp xp theo th t:Ion ccboni bc 3> Ion ccboni bc 2 >Ion ccboni bc 1 bn ca cacboni s quyt nh s quyt nh mc tham gia cc phn ng tip theo cachng.Cht lng sn phm c quyt nh bi cc phn ng ca cc ion cacboni, c bit lphn ng phn hy, ng phn ha v chuyn v hydro.- Giai an 3: giai an dng phn ngKhi cc ion cacboni kt hp vi nhau, nhng hay nhn nguyn t hydro ca xc tc to thnhphn t trung ha v chng chnh l cu t ca sn phm cracking xc tc.

Qu trnh Cracking xc tc (P2): Qu trnh ha hc(ng ngy 30.01.2008 11:27 & 3002 lt xem)

Qu trnh ha hc xy ra trong Giai on cracking xc tc rt phc tp, nhiu phn ng xy ra, cmong mun v khng mong mun.

3. Ha hc qu trnh cracking xc tc

3.1 Cc phn ng mong mun

Phn ng ct mch (cracking ): xy ra theo c ch ion cacbonium.

Hot tnh cracking ca cc hydrocacbon gim dn theo th t sau:

Olefin > Ankyl Aromatic > Ankyl naphten, isoparafin> n-parafin, naphten>> nhn thm. Tc

cracking tng khi s nguyn t cacbon tng, phn nhnh tng. Phn ng isomer ho: Thngxy ra trc phn ng cracking. Nhng sau cracking qu trnh t xy ra do thi gian lu trong bnhFCC ngn v mch ngn ln cn tr qu trnh isomer ho.


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3.2 Cc phn ng khng mong mun.

Phn ng chuyn v hydro: Phn ng ny xy ra s chuyn v mt phn t hydro t mthydrocacbon ny sang mt hydrocacbon khc (khng no) dn n hnh thnh cc hp cht no vthm.

Lm gim olefin, tng Aromatic tng kh nng to cc.

Lm gim ch s octan xng (mt olefin). Lm xng n nh hn. Phn ng ngng t:

Polymer ho olefin ng vng dehydro ho to Aromatic.

Ankyl ho Aromatic ng vng nhnh ankyl hydro ho poly

Aromatic (cc). Cng ng vng Diels Alder dehydro ho poly Aromatic.

Hai phn ng trn cn hn ch (to cc) nhng khng loi b (gim olefin). Phn ng to hydro:do phn ng dehydro ho, xy ra khi c mt ca Ni lm cht xc tc. Phn ng to C1 C2: sinh ra

do phn ng cracking nhit. Cc phn ng ha hc xy ra trn tng dng hydrocacbon ring lc trnh by trong bng sau:

Hydrocacbon Sn phm qu trnh cracking xc tc

Parafin -Olefin v parafin

-Olefin v hydro

-iso-parafin

-Cc hp cht olefin c trng lng phn t thp


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Olefin -Parafin v dien

-Parafin, naphten v hydrocacbon thm

-Polyme, cc

Naphten -Olefin

-Cyclohexan v olefin

-Hydrocacbon thm

Hydrocacbon

thm

(alkyl thm)

-Parafin v alkyl c mch bn ngn

-ng phn ha, chuyn v nhm alkyl

-Sn phm ngng t v cc.

Phn ng bc 2:

Naphten+ Olefin

-Hydrocacbon thm

-Parafin

Hydrocacbonthm +Olefin

-Sn phm ngng t v cc

4. Nguyn liu v sn phm4.1 Nguyn liuNguyn liu cho qu trnh cracking xc tc thng c khang nhit si t 300-500oC, c th tcc ngun nh sau: Phn an ct chng ct kh quyn ca du th, khang si: 380-410oC Phn an ct chng ct chn khng ca du th, khang si: 380-550oC Phn ct t qu trnh Coking ca du th DAO (cn chn khng deasphaltene) (550oC) Cn chng ct kh quyn ( > 380oC) ca vi lai du thNguyn liu l nhng phn ct nh s cho sn phm c hiu sut C3, C4tng cn H2 v cc gim. Nhng phn an nh (200- 360oC) nhn c t chng ct trc tip lnguyn liu tt nht sn xut xng t v xng my bay.Nguyn liu t cc phn an nng (cc gasoil) chn khng l ph bin nht trong qu trnhcracking xc tc. Nhm ny cho sn phm l xng v cc phn an sn phm trng, qua chng ctchn khng lm gim nhng cu t v hp cht c hi cho qu trnh cracking. Thc t l thnhphn nhng kim lai nng lm nhim c xc tc nh vanadi, niken thng c trong cc hp chtc kim, trong thnh phn ca nha, asphalten l nhng phn t ln,c nhit si cao, khi chng ct chn khng nhng cht ny s li phn cn ca chng ct chnkhng, chnh v vy m cc phn ct c lm sch, c lai v c gim cc cht gynhim c xc tc. Cng chnh cc hp cht nha, asphalten khng nhng cha cc kim lai nng

m chng cn l ngun chuyn thnh cc nhiu nht, lm gim hat tnh ca xc tc.Thnh phn ha hc ca nguyn liu nh hng rt ln n hiu sut ca qu trnh. Vi nhmhydrocacbon parafin s cho hiu qu chuyn ha cao nht. Nhm hydrocacbon thm cho hiu sutxng km hn v li tng mc chuyn ha to cc. Nhng cht phi hydrocacbon l c hi cho qu trnh cracking xc tc, chnggy ng c cho xc tc v cn chuyn vo sn phm lm gim cht lng sn phm nh cc hpcht lu hunh.Trong thc t vi s tin b ca cng ngh, qu trnh cracking xc tc c th s dng cn chngct kh quyn lm nguyn liu trc tip cho qu trnh m khng phi qua chng ct chnkhng. Qa trnh ny gi l qu trnh cracking xc tc cn (RFCC). Nhng lai du thparafin, t lu hynh thng c t cc cht gy nhim c xc tc v ch s cc Conradson thp rtthun li cho vic dng thng cn chng ct kh quyn lm nguyn liu cho qu trnh RFCC. tng ngun nguyn liu, ngay c cn chng ct chn khng cng c lm nguyn liu cho

qu trnh cracking xc tc sau khi kh nha v asphalten.4.2 Sn phm


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Cht lng ca sn phm cracking xc tc thay i trong phm vi rt rng ph thuc vo rt nhiuyu t nh nguyn liu, lai xc tc v cc thng scng ngh ca qu trnh. Hn hp sn phm ca qu trnh cracking c chuyn tip nthit b chng ct phn ra cc phn an sn phm:- Sn phm kh,- Cc phn an xng, du ha,

- Cc phn an gasoil nh v nng.- Phn an cn dng lm nhin liu t l...c im cc sn phm kh v lng thu c t qu trnh cracking xc tc:Kh hydrocacbonHiu sut kh c th t 10-25% nguyn liu ph thuc vo nguyn liu v iu kin cracking.Trong iu kin nhit cao, tc nguyn liu nh, bi s tun han xctc ln th hiu sut sn phm kh s ln v ngc li th hiu sut kh nh.Nguyn liu chm lng lu hynh cao th sn phm kh c nhiu kh H2S v khi nguyn liu c nhiu nit th snphm kh cracking c nhiu NH3.Sn phm kh, kh kh c dng lm nhin liu kh, Etylen v Propylen l nguyn liu cho snxut nha Polyetylen(PE) v Polypropylen (PP), Propan-propen lm nguyn liu cho qu trnhpolyme ha v sn sut cc cht hat ng b mt v lm nhin liu t (LPG).Propan-propen, butan-buten cn lm nguyn liu cho qu trnh alkyl ha nhn cu t c tr s

octan cao pha vo xng, v lm nguyn liu cho cc qu trnh tng hp ha du.Phn an xngPhn an xng thng c nhit 40-200oC, phn an ny l cu t c bn pha trn vinhng cu t khc t cc qu trnh Reforming, alkylha,v cc phn an naphta t qu trnh chng ct trc tip sn xut cc lai xng t, xng mybay.Phn an xng t qu trnh cracking xc tc khc vi cc phn an c cng khang nhit sit qu trnh chng ct trc tip l c tr s octan cao hn v c bit l c thm thnh phnhydrocacbon olefin.Phn an 200-280oCDng lm du ha v phn an 200-350oC c dng pha trn v sn xut nhin liu diezenCc phn an > 350oCc dng lm nhin liu t l F.O hay c dng lm nguyn liu cho qu trnh cc ha.

Qu trnh Cracking xc tc (P3): Cng ngh tiu biu(ng ngy 30.01.2008 12:29 & 4858 lt xem)

Qu trnh Cracking xc tc bt u pht trin cng ngh t nm 1936 do mt k s ngi Php thitk tn l Houdry. Sau cng ngh bt u ci tin dn v ngy cng a dng cng ngh, p dngcho tng loi nguyn liu v mc ch sn phm.

5. Cc cng ngh cracking xc tc tiu biu

5.1 Cracking vi lp xc tc c nh

Dy chuyn cracking xc tc u tin do Houdry, mt k s ngi Php thit k c a vo cngnghip ch bin du t nm 1936. Cng ngh ny hat ng theo kiu gin an vi lp xc tc cnh. Nhc im ca cng ngh ny l hat ng gin an v vy rt phc tp trong vn hnh(qu trnh cracking ng xc tc cho sn phm v ti sinh xc tc trong cng mt thit b). Dychuyn ny nhanh chng c ci tin v ch nm nm sau, nm 1941 xut hin qu trnhcracking vi lp xc tc chuyn ng.

5.2 Cracking vi lp xc tc tng si

Qa trnh cracking c lp xc tc chuyn ng thay th qu trnh Houdry. Qa trnh phnng xc tc v ti sinh xc tc c thc hin cc thit b ring bit: thit b phn ng (l phnng) v thit b ti sinh xc tc (l ti sinh). Xc tc lm vic c cha cc chy t l phn ngvo l ti sinh v sau khi ti sinh li ngc v l phn ng (hoc bng t chy hoc bng


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cng bc) to thnh mt chu trnh lin tc. Nm 1942 quy trnh cracking c lp xc tcchuyn ng (FCC) u tin c a vo hat ng c tn l Up Flow.

Nm 1944 ngi ta tng ng knh ca l phn ng v l ti sinh, tch hi sn phm c thchin ngay trong l phn ng v ti sinh xc tc dng tng si v qu trnh thi cho xc tc chuynng t pha di v ly ra ngai y l. Dy truyn hat ng nh vy c tn l Down Flow.Ngi ta lin tc ci tin thit b v c hnh dng ca xc tc. Hnh dng xc tc ph bin l dngvin hnh cu nhm lm gim s mt mt xc tc v gim s mi mn thit b v nng cao hiu qutch ca xyclon. Model I, t l xc tc/nguyn liu ch t ti a l 3 nhng model II c th tng tia l 10. Hng M.B.Kellog thit k lai cn bng p sut Model III nm 1946. Hng Standard-Oil(New Jersey) thit k lai FCC mi (Model IV) t ci tin ca Model II v a vo hat ngt 1952. Cng ngh FCC ngy cng c ci tin nhm t hiu sut v cht lng xng cao hn,vi cht lng nguyn liu ngy cng xu hn.


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Cng ngh FCC ca mt s hng cng nghip ni ting gm c:

5.3 Cng ngh ca hng UOP

Qua cc bc ci tin lin tc, hin nay cng ngh FCC ca UOP cng p dng cracking nhm

chuyn ha cn du nng. Qa trnh ca UOP c cng ty Ashland OilCo pht trin. Chnh hngUOP thit k 2 lai FCC: lai l ti sinh t chy han tan 1 cp v lai ti sinh hai cp. Lai lti sinh t chy han tan mt cp: l lai thng dng trn tan th gii, nhng UOP ci tin hthng phn phi nguyn liu phn cui ca ng riser, h thng ti sinh xc tc, b phn lm lnh xctc, xc tc nng cao tnh linh ng ca nguyn liu cng nh sn phm ca qu trnh. Xc tcsau phn ng c t dng tng si, tc cao, nhm chuyn ha han tan CO thnh CO2,khng s dng thm cc ph gia khc v hm lng cacbon cn li trn b mt xc tc sau ti sinhl thp nht so vi cc cng ngh thng thng. Lai L ti sinh hai cp: C bn nh cngngh FCC thng thng nhng c thit k c bit cho nguyn liu cn nng hn (RFCC, vi4-10 % cn cacbon conradson trong nguyn liu). L ti sinh xc tc chia lm hai tng, vi b phnlm lnh xc tc c b tr bn trong v c ci tin kim sat lng cc, lng nhit chophn phn ng. Tng th nht pha trn c nhim v t chy mt phm hm lng cc trn bmt xc tc, tng th hai, lng cc cn li trn b mt xc tc s c t chy han tan. iu

ny dn n hm lng cacbon cn li trn b mt xc tc lun < 0.05 % khi lng.

5.4 Cng ngh ca Kellog

S vn chuyn xc tc c thc hin theo phng thng ng rt thun li v c th dng vanchn iu khin qu trnh tun han ca xc tc. Qa trnh cracking c thc hin hantan trong l phn ng dng ng ng (l ng ng). H thng xyclon c t ngay ca raca ng ng. Trong l ti sinh xc tc v khng kh tip xc ngc chiu nhau. Kiu RFCC ctrnh by trong hnh 10. c im chnh ca model ny l vi phun nguyn liu c ci tinnhm tng cng s tip xc gia xc tc v nguyn liu, b phn lm ngui c thay ibng cch t t pha c thay cho pha lang trong l ti sinh trnh n mn, mi mn trangthit b do xc tc v nhm lm tng tc truyn nhit. Hnh dng b phn lm ngui xc tc doKellog thit k cng tng t ca UOP ch khc l cch b tr cc ng trao i nhit t ngcchiu


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5.5 Cng ngh ca hng Shell

Shell c nhiu ng gp trong vic pht trin cracking xc tc phn cn nng (RFCC). Qu trnhShell LRFCC (Long Residue FCC) cracking xc tc cn nng v rng, c b phn lm ngui xctc trnh s t chy qu nhit. Thit b trnh by trong hnh sau:


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5.6 Cng ngh IFP Total v Stone & Webster Hai hng cng nghip ny hp tc tht k qutrnh RFCC vi ti sinh xc tc 2 cp. Qa trnh nhm cracking xc tc cn nng v c tn l R.2.RProcess. Qa trnh cng c trang b b phn lm ngui xc tc, h thng kim tra v iu khinnhit ca khi l phn ng. c im ca cng ngh R.2.R l l ng, ti sinh 2 cp, c s citin thit b phun nguyn liu trc tip vo dng xc tc nng.


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5.7 Cng ngh Exxon Exxon lin tc nghin cu ci tin cng ngh FCC, t khi a ra model IV vn nay a ra lai model III-R, cracking c c tnh linh hat. C th s dng nguyn liu khcnhau t cc phn ct chn khng n cc lai cn nng.

Qu trnh Cracking xc tc (P4): Cc yu t nh hng

c im cng ngh FCC l qu trnh cracking xc tc tng si (gi si), qu trnh thc hin trndng xc tc chuyn ng lin tc trong l phn ng cng nguyn liu v sang l ti sinh thchin vic t cc (dng vi oxy khng kh) trn xc tc tham gia phn ng ri li sang l phnng. Chu trnh trn c lp li mt cch lin tc.

6. Cc yu t nh hng n cng ngh FCCCng ngh FCC hat ng vi nhng thng s quan trng sau: chuyn ha, tc np liu; t lxc tc /nguyn liu; nhit ; p sut.6.1 chuyn ha chuyn ha C c tnh bng:C = Tng hiu sut (kh +Xng +Cc) C= 100- y(100-z)y: l % th tch ca sn phm c nhit si cui cao hn im si cui ca xngz: l % th tch xng c trong nguyn liu..


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S khi qu trnh FCC6.2 Tc np liuL t s gia lng nguyn liu c np trong mt n v thi gian trn lng xc tc trong lphn ng.v c k hiu bng M/H/M

Khi tng tc np liu s lm gim chuyn ho v ngc li v tc np liu l i lngngc vi thi gian phn ng. Khi s dng xc tc c hat tnh cao ta c th tng tc npliu khi y s tng nng sut ca thit b.6.3 T l xc tc/Nguyn liuT l xc tc zeolit/nguyn liu,cn gi l bi s tun han xc tc (X/RH). Vi lai xctc zeolt th X/RH=10/1 cn xc tc v nh hnh X/RH=20/1. Khi thay i t l X/RH s lmthay i thi gian lu ca xc tc trong l phn ng v l ti sinh v thay i c lng cc bm trnxc tc. ch n nh t l X/RH tng s lm tng chuyn ha v gim hm lng ccbm trn xc tc, khi thi gian tip xc gia xc tc v nguyn liu gim nhng hat tnh trungbnh ca xc tc li tng ln.6.4 Nhit Nhit trong l phn ng khi vn hnh trong khang 470-540oC. Khi nhit tng ln th tc phn ng phn hy nhanh hn nhng cng thc y cc phn bc 2 nh kh hydro tng ln

dn n tng hiu sut hydrocacbon thm v olefin. Khi C1-C3 trong kh tng, C4 gim, ttrngv tr s octan ca xng tng ln.Khi nhit cao hiu sut xng gim, hiu sut kh tng v cc khng tng.6.5 p sutKhi p sut tng th hiu sut xng tng ln, hiu sut C1-C3 gim, hm lng olefin vhydrocacbon thm gim dn ti tr s octan ca xng gim.6.6 Ti sinh xc tc cracking s dng xc tc c lu, trong cng ngh phi thc hin vic ti sinh xc tc. Nguyn nhnchnh lm mt hat tnh ca xc tc l do cc tothnh bm kn b mt hat tnh ca xc tc. ti sinh xc tc ngi ta tin hnh t cc bng khng kh nng trong l ti sinh. Khi t ccs to thnh CO, CO2, cc phn ng kh cc hp cht lu hynh.

C + O2 CO2

C + 1/2O2 CO

CO + 1/2O2 CO2

H2 + 1/2O2 H2O

S + O2 SO2

SO2 + 1/2O 2 SO3MeO + SO3 MeSO4

MeSO4 + 4H2 MeO + H2S + 3H2O

Nhit lng ta ra c dng cp nhit cho xc tc mang vo l phn ng cracking.

qua trinh cracking xuc tac 9904

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