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8/12/2019 N nh gi s a nh hng cu a tnh ch t nguyn li u n hi u qua phu gia ZSM-5 trong qu trnh FCC

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n Tt Nghip i Trung Tm NC&PTCB Du Kh

LI CM N

c c thnh cng trong n tt nghip ny, u tin em xin gi li cm nchn thnh n Ban gim c Trung Tm Nghin Cu v Pht Trin ChBin DuKh to iu kin thun li cho em n thc tp ti Qu Cng ty.

Bn cnh , em xin gi li cm n n cc anh chti Trung Tm Nghin Cu vPht Trin ChBin Du Kh ni chung v cc anh ch ti cc n v phn cngthc tp ni ring, c bit l Th.S Ng Thy Phng tn tnh hng dn em tnhng bc i u tin n nhng bc cui cng trong lun vn. ng thi choem gi li cm n n TS. ng Thanh Tng, TS. Nguyn Hoi Thu, KS. o Th

Thanh Xun, KS. Nguyn Sura, KS. Nguyn Hu Trng,KTV. Trn Vn Tr, ...phng Nghin Cu v nh Gi Xc Tc lun quan tm, cung cp nhng kinthc cn bn, chia skinh nghim, kin thc em hon thnh v hon thin hnti tt nghip ny.

V pha nh trng, em xin chn thnh cm n lnh o nh trng cng ccthy c thuc Khoa Ha KThut i hc Bch Khoa Nng to iu kincng nhtrang bcho em nhng kin thc nn tng trc khi c nhn vo thctp ti Trung Tm Nghin Cu v Pht Trin ChBin Du Kh.

Vpha bn b, cm n tt cnhng ngi bn gip vmt tinh thn cngnhvt cht trong t thc tp ny.

Cui cng em knh chc qu thy c, Ban gim c cng vi cc anh chcn bnhn vin Trung Tm Nghin Cu v Pht Trin Ch Bin Du Kh di do sckho, thnh cng v hnh phc.

Do thi gian thc tp ngn v vi vn kin thc cn hn chnn khi i vo thctcn gp khng t kh khn, bng, do bo co trnh by khng thtrnh khinhng sai st. Knh mong c squan tm v ng gp kin ca qu thy c v

cc anh chtrong Cng ty bi bo co thc tp ca em c hon thin hn.

Xin chn thnh cm n.

DIN N TON - L - HA 1000B TRN HNG O TP.QUY NHN

WWW.DAYKEMQUYNHON.UCOZ.COM


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n Tt Nghip ii Trung Tm NC&PTCB Du Kh

MC LC

LI CM N ............................................................................................................. iMC LC .................................................................................................................. iiDANH MC HNH V BNG BIU ................................................................... vii

DANH MC HNH ............................................................................................. viiDANH MC BNG BIU ................................................................................ viii

CC K HIU VIT TT ..................................................................................... ixLI MU ........................................................................................................... xiCHNG 1: TNG QUAN QU TRNH FCC ................................................... 1V ZEOLITE ZSM-5 ............................................................................................... 1

1.1. Nhu cu sdng propylen v cc olefin nh ................................................ 11.1.1. Etylen ......................................................................................................... 11.1.2. Propylen ..................................................................................................... 11.1.3. Butylene ..................................................................................................... 1

1.2. Qu trnh FCC ................................................................................................ 11.2.1. Mc ch, vai tr ca qu trnh cracking xc tc .................................... 11.2.2. Cng nghcracking xc tc tng si ....................................................... 21.2.3. Cng nghRFCC ca NMLD Dung Qut ............................................... 31.2.4. Csl thuyt ca qu trnh cracking xc tc ....................................... 4

1.2.4.1. Cchphn ng: l cchion cacboni .............................................. 41.2.4.2. Cc phn ng chnh ca qu trnh FCC ............................................... 6

1.3. Nguyn liu ...................................................................................................... 71.3.1. Nguyn liu sdng cho qu trnh FCC ................................................. 71.3.2.c trng vnguyn liu .......................................................................... 7

1.3.2.1. Phn loi cc hydrocacbon ................................................................... 7




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n Tt Nghip iii Trung Tm NC&PTCB Du Kh

1.3.2.2. Cc tnh cht vt l ca nguyn liu FCC ........................................... 81.3.2.3. Cc tp cht ........................................................................................ 101.3.2.4. Cc kim loi ....................................................................................... 12

1.4. Sn phm ....................................................................................................... 141.4.1. Kh kh ..................................................................................................... 141.4.2. LPG v cc olefin nh ............................................................................. 141.4.3. Xng FCC ................................................................................................ 151.4.4. LCO .......................................................................................................... 151.4.5. HCO v DO .............................................................................................. 15

1.4.6. Cc ............................................................................................................ 15

1.5. Xc tc FCC .................................................................................................. 161.5.1. Cu trc xc tc FCC.............................................................................. 161.5.2. Thnh phn xc tc FCC ....................................................................... 17

1.5.2.1. Pha hot tnh Zeolite .......................................................................... 171.5.2.2. Cht nn ............................................................................................. 18

1.6. Zeolite ZSM-5 ................................................................................................ 181.6.1. Cu trc zeolite ZSM-5 ........................................................................... 181.6.2. Thnh phn ha hc ca ZSM-5 ............................................................ 191.6.3. Tnh cht ca zeolite ZSM-5 ................................................................... 19

1.6.3.1. Tnh axit ............................................................................................. 191.6.3.2. Tnh cht chn lc hnh dng ............................................................. 191.6.3.3. Tl Si/Al .......................................................................................... 20

1.6.3.4. bn thy nhit ............................................................................... 21

1.6.4. nh hng ca ZSM-5 n hiu sut propylen, trsoctan ca xngv ccu sn phm ca qu trnh FCC ........................................................... 21

1.6.4.1. nh hng ca ZSM-5 n hiu sut propylen ................................. 211.6.4.2. nh hng ca ZSM-5 n sgia tng trsoctan ca xng ........... 221.6.4.3. nh hng ca ZSM-5 n ccu sn phm ca qu trnh FCC ..... 22

CHNG 2: THC NGHIM ............................................................................. 23




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n Tt Nghip iv Trung Tm NC&PTCB Du Kh

2.1. i tng thc nghim ................................................................................. 232.1.1. Nguyn liu .............................................................................................. 232.1.2. Xc tc ..................................................................................................... 242.1.3. Ph gia ..................................................................................................... 25

2.2. Phng php thc nghim ........................................................................... 262.2.1. Xc nh hot tnh v chn lc ca xc tc FCC ............................ 26

2.2.1.1. Nguyn l phng php ..................................................................... 262.2.1.2. Thit b, tiu chun ............................................................................ 26

2.2.1.3. Phng php thc nghim ................................................................. 27

2.2.1.4. Xc nh kt qu ................................................................................ 272.2.2. Gim hot tnh xc tc FCC bng phng php thy nhit ................. 28

2.2.2.1. Nguyn l phng php ..................................................................... 282.2.2.2. Thit b, tiu chun ............................................................................ 282.2.2.3. Phng php thc nghim ................................................................. 282.2.2.4. Xc nh kt qu ................................................................................ 292.2.2.5. Sai sca phng php ..................................................................... 29

2.2.3. Xc nh thnh phn kh cracking ......................................................... 302.2.3.1. Nguyn l phng php ..................................................................... 302.2.3.2. Thit b, tiu chun ............................................................................ 302.2.3.3. Phng php thc nghim ................................................................. 302.2.3.4. Xc nh kt qu ................................................................................ 30

2.2.4. Phn bkhong nhit si ca cc phn on lng du m............ 31

2.2.4.1. Nguyn l phng php ..................................................................... 312.2.4.2. Thit b, ti liu .................................................................................. 312.2.4.3. Phng php thc nghim ................................................................. 312.2.4.4. Xc nh kt qu ................................................................................ 31

2.2.5. Xc nh hm lng Cacbon, Lu hunh ............................................. 322.2.5.1. Nguyn l phng php ..................................................................... 322.2.5.2. Thit b, tiu chun ............................................................................ 32




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n Tt Nghip v Trung Tm NC&PTCB Du Kh

2.2.5.3 Phng php thc nghim .................................................................. 322.2.5.4. Xc nh kt qu ................................................................................ 33

2.2.6. Xc nh trsRON v MON ca phn on xng ............................. 332.2.6.1. Nguyn l phng php ..................................................................... 332.2.6.2 Thit b, tiu chun ............................................................................. 332.2.6.3. Phng php thc nghim ................................................................. 332.2.6.4. Xc nh kt qu ................................................................................ 34

2.2.7 Sai sca phng php ........................................................................... 34

CHNG 3: KT QUV THO LUN ......................................................... 36

3.1. Kt quv nh gi i tng thc nghim .............................................. 363.1.1.nh gi i tng thc nghim............................................................ 36

3.1.1.1. nh gi nguyn liu ......................................................................... 363.1.1.2. nh gi phgia ................................................................................ 36

3.1.2. Kt quthc nghim ............................................................................... 363.2. Tho lun ....................................................................................................... 40

3.2.1. nh hng ca nguyn liu n hiu sut propylen vi sc mt caphgia ZSM-5 ................................................................................................... 403.2.2.nh hng ca nguyn liu n chuyn ha vi sc mt ca phgia ZSM-5 .......................................................................................................... 413.2.3. nh hng ca nguyn liu n ccu sn phm vi s c mt caphgia ZSM-5 ................................................................................................... 42

3.2.3.1. Hiu sut kh kh ............................................................................... 423.2.3.2. Hiu sut LPG .................................................................................... 453.2.3.3. Hiu sut phn on xng .................................................................. 483.2.3.4. Hiu sut phn on LCO .................................................................. 503.2.3.5. Hiu sut phn on HCO ................................................................. 513.2.3.6. Hiu sut phn on cc .................................................................... 52

3.2.4.nh hng ca phgia ZSM-5 n trsoctan ca xng cracking ... 533.2.4.1. Sthay i trsoctan ca xng ....................................................... 53




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n Tt Nghip vii Trung Tm NC&PTCB Du Kh

DANH MC HNH V BNG BIU

DANH MC HNH

Hnh 1.1: Scng nghFCC .................................................................................. 2Hnh 1.2: Scng nghR.2.R ca hng IFP Total v Stone & Webster ............ 3Hnh 1.3: nh chp SEM ca ht xc tc ................................................................. 16Hnh 1.4: Cu to ht xc tc .................................................................................... 16Hnh 1.5: Cu to cszeolite ................................................................................. 17Hnh 1.6: Hnh dng zeolite ...................................................................................... 17Hnh 1.7: Cu trc tinh thzeolite Y v ZSM-5 ....................................................... 18Hnh 1.8: nh hng ca xc tc n sn phm ca phn xng FCC ................... 21Hnh 2.1: Squy trnh thc nghim ca ti .................................................... 23Hnh 2.2: Sthit bMAT .................................................................................... 26Hnh 2.3: Sthit b AM-1500............................................................................. 28Hnh 2.4: Sthi gian gia nhit ca phng php thy nhit ............................. 29Hnh 3.1: nh hng ca nguyn liu v nng phgia n hiu sut propylen . 40Hnh 3.2: nh hng ca nguyn liu v nng phgia n chuyn ha ....... 41Hnh 3.3: nh hng ca nguyn liu v nng phgia n chn lc kh kh................................................................................................................................... 43

Hnh 3.4: nh hng ca nng phgia n thnh phn kh kh ca nguyn liuA1 .............................................................................................................................. 43Hnh 3.5: nh hng ca nguyn liu v nng phgia n hiu sut LPG ........ 45Hnh 3.6: nh hng ca nguyn liu v nng phgia n tng C3+C4parafin 46Hnh 3.7: nh hng ca nguyn liu v nng ph gia n hiu sut C3+C4

olefin.......................................................................................................................... 47Hnh 3.8: nh hng ca nguyn liu v nng phgia n tsC3

=/C4=.......... 48

Hnh 3.9: nh hng ca nguyn liu v nng phgia n hiu sut thu xng . 48Hnh 3.10: nh hng ca nng phgia n hiu sut xng, propylen v thnhphn I, O trong xng ca nguyn liu A1 ................................................................. 49Hnh 3.11: nh hng ca nguyn liu v nng phgia n hiu sut LCO ..... 50Hnh 3.12: nh hng ca nguyn liu v nng phgia n hiu sut HCO ..... 51




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n Tt Nghip viii Trung Tm NC&PTCB Du Kh

Hnh 3.13: nh hng ca nguyn liu v nng ph gia n chn lc snphm cc ................................................................................................................... 52Hnh 3.14: nh hng ca nguyn liu v nng phgia n trsoctan ca xng................................................................................................................................... 53

Hnh 3.15: nh hng ca nguyn liu v nng phgia n trsoctan v hiusut thu xng ca nguyn liu A1 ............................................................................. 54Hnh 3.16: nh hng ca nguyn liu v nng phgia n thnh phn PIONAtrong xng ca nguyn liu A1.................................................................................. 55Hnh 3.17: nh hng ca nguyn liu v nng phgia n thnh phn PIONAca nguyn liu A1 trn nguyn liu ......................................................................... 55

DANH MC BNG BIU

Bng 1.1: Thnh phn ha hc ca zeolite Y v H-ZSM-5 ...................................... 21Bng 2.1: Mt stnh cht v thng squan trng ca nguyn liu ........................ 24Bng 2.2: Tnh cht c trng ca xc tc ................................................................ 24Bng 2.3: Mt stnh cht ca phgia mi X ......................................................... 25Bng 2.4: Tm tt sai sca cc sn phm .............................................................. 35Bng 3.1: Sliu thc nghim ca nguyn liu A1 v A2 ....................................... 37Bng 3.2: Sliu thc nghim ca nguyn liu P1 v P2 ........................................ 38Bng 3.3: So snh thnh phn kh kh ca nguyn liu A1 v P1 ............................ 44Bng 3.4: Thnh phn PIONA trong xng ca nguyn liu A1 ................................ 49Bng 3.5: So snh thnh phn PIONA trong xng ca nguyn liu A1 v P1.......... 56Bng 3.6: Sthay i hiu sut mt ssn phm .................................................... 57




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n Tt Nghip ix Trung Tm NC&PTCB Du Kh

CC K HIU VIT TT

RI : Refractive Index (Chskhc x)

MTBE : Methyl Tertiary Buthyl Ether

ETBE : Ethyl Tertiary Buthyl Ether

CPS : Cyclic Proplylene Steaming

ASTM : American Society for Testing and Materials

C/O : Catalyst/Oil

E-cat : Equilibrium Catalyst

FCC : Fluid Catalytic Cracking

RFCC : Residue Fluid Catalytic Cracking

LPG : Liquified Petroleum Gas

LCO : Light Cycle Oil

HCO : Heavy Cycle Oil

DO : Decanted Oil

MAT : Microactivity Test

R2R : one Reactor and Two Regenerator

RE2O3 : Rare Earth

RON : Research Octane Number

VGO : Vacuum Gasoil

NMLD : Nh my lc du

SA : Surface Area

Ze/Mx : Tldin tch bmt Zeolite so vi Matrix

SCT_MAT : Short Contact Time Microactivity Test

PIONA : Parafin, Iso-parafin, Aromat, Naphthene, Olefin

PE : Polyetylen

PP : Polypropylen

PVC : Polyvinyl Clorua

PG : Poly Glycol

RA : Residue Atmospherique

VGO : Vacuum Gas Oil

MTC :Mix Temperature Control




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n Tt Nghip x Trung Tm NC&PTCB Du Kh

RTD :Riser Temperature Device

DI : Davision Index

HC : HydrocacbonAP : Anilin Point

CCR : Carbonconradson

WGC : Wet Gas Compressor

SA : Surface Area

UCS : Unit Cell Size

FID : Flame Ionization Detector

TCD : Thermal Conductivity DetectionSIMDIST : Simulated Distillation

GC GAS : Gas Chromatography




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n Tt Nghip xi Trung Tm NC&PTCB Du Kh

LI MU

Nhng nm gn y nhu cu vcc olefin nh(etylen, propylen, butylen,) cbit l propylen - sn phm ch yu tng hp nha polypropylen (PP) khngngng tng.

Nm 1980 nhu cu ton cu i vi propylen l 16,4 triu tn v tng ln 68 triutn vo nm 2005 (trung bnh mi nm tng 6%). Nhu cu sdng propylen l 81triu tn vo nm 2010. Nhu cu propylen tng chyu l do nhu cu sdng PPtng, tnay n nm 2012, nhu cu PP c thtng 7%/ nm.1

Nhu cu sdng propylen tng stc ng trc tip n hot ng sn xut, ngunnguyn liu v cng nghsn xut. Trong khi ngun nguyn liu ngy cng c chtlng xu i i hi cng nghphi i trc mt bc.

Hin nay, c nhiu cng nghmi nhm u tin to ra sn phm propylen trong qutrnh chbin du mnh:

Qu trnh cracking naphta bng hi nc c xc tc Qu trnh cracking du th c xc tc - qu trnh FCC Dehydro ha kh propan Chuyn ha metanol thnh propylen

Trong scc phng php sn xut propylen ktrn, hai phng php u l phbin nht. Trong hin nay phng php cracking naphta bng hi nc chim ttrng 67%, phng php FCC chim 30%, chc 3% cho cc phng php cn li.Tuy nhin theo dbo ca CMA.Inc (Chemical Market Associates), n nm 2010,ttrng ln lt sl: cracking naphta bng hi nc l 59%, qu trnh FCC l33% v 8% cho cc phng php cn li.2

Trong qu trnh FCC, nng cao hiu sut sn phm propylen cc nh sn xut thm vo trong xc tc cht phgia ZSM-5. Tuy nhin, do ngun nguyn liu

lun thay i trong khi nhu cu propylen vn tng i hi nh my phi c nhngiu chnh ph hp. V vy, mc ch ca ti ny l nh gi snh hng catnh cht nguyn liu n hiu quphgia ZSM-5 trong qu trnh FCC. T, chophp la chn loi nguyn liu thch hp cho nh my va p ng c nhu cuthtrng va em li hiu qukinh tcao nht.

1http://congnghedaukhi.com/index.php?showtopic=9462http://congnghedaukhi.com/modules.php?name=News&op=viewst&sid=36




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n Tt Nghip 1 Trung Tm NC&PTCB Du Kh

CHNG 1: TNG QUAN QU TRNH FCC

V ZEOLITE ZSM-51.1. Nhu cu sdng propylen v cc olefin nh

Vai tr ca olefin trong ha du

Olefin c c trng bi khnng phn ng cao hn so vi cc hydrocacbonparafin. Chng phn ng ddng vi cc cht c sn v rtin nh: nc, oxy, clo,brom, axidclohydric,. to thnh nhng sn phm c gi tr nh: vinylclorua,axit acrylic, ru isopropyl, oxit propylen,. Cc olefin nhc dng tnghp cc polymer c gi trnh: PE (polyetylen), PP (polypropylen),. Cc olefinnhquan trng trong ha du phi kn l: etylen, propylen, butylen,.

1.1.1. Etylen

Etylen l olefin quan trng nht v c sdng nhiu trong cng nghip hadu. Etylen c nhiu ng dng quan trng trong thc t: sn xut PE (HDPE,LDPE, LLDPE), PVC, etylbenzen,.

1.1.2.Propylen

Propylen l mt hydrocarbon khng no ch

a m

t lin k

ti v c cng th

c hahc l C3H6. iu kin mi trng propylen l cht kh khng mu, c mi nh.

Propylen l nguyn liu quan trng ng hng thhai trong cc sn phm hadu. Cc dn xut ch yu ca propylen gm polypropylen, acrylonitril, oxitpropylen, cumen/phenol, ru oxo, axit acrylic, ru isopropyl, oligome v cc chttrung gian khc.

Propylen c nhiu ng dng quan trng trong thc t: sn xut PP, PG, .

1.1.3. Butylene

Cng nhetylen v propylen, butylen cng c nhiu ng dng trong thc t:

Butylen phn ng vi propylen to ra copolymer LLDPE. Sn xut cc phgia ci thin chsoctan trong xng: MTBE, ETBE, v

cc ha cht quan trng khc nhacetic anhydride, MEK,

1.2. Qu trnh FCC

1.2.1. Mc ch, vai tr ca qu trnh cracking xc tc

Cracking xc tc l qu trnh bin i cc phn on nng ca du m(cn chng

ct kh quyn: RA, cn chng ct chn khng: RSV, gasoil chn khng:VGO,) c




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gi trkinh tthp vi sc mt ca cht xc tc nhm thu c cc phn on nhhn c gi trkinh tcao (propylen, xng, LCO,).

1.2.2. Cng nghcracking xc tc tng siBao gm 3 bphn chnh sau:

Thit b phn ng: bao gm ng ng (riser) v b phn phn tch sn phmbng hi nc (stripper).

ng ng l ni din ra phn ng cracking rt nhanh gia dng xc tc vdng nguyn liu c gia nhit (chtrong khong vi giy).

B phn stripper b tr pha cui ca ng ng c nhim v tch cc hihydrocacbon ra khi dng xc tc. Hi sn phm sau c dn v thp

chng ct cn xc tc sc tip tc lun chuyn sang thit bti sinh.Thit bti sinh (regenerator): ti y cc bm trn xc tc bt chy mt phn

hoc hon ton bng khng kh. Qu trnh ny lm cho hot tnh xc tc cphc hi tip tc lun chuyn sang l phn ng thc hin chu trnh crackingktip. Xc tc sau khi ra khi l ti sinh c gi l xc tc ti sinh hay xc tccn bng (regenerated catalyst hay equilibrium catalyst) v xc tc sau khi rakhi cm thit bphn ng c gi l xc tc qua sdng (spent catalyst).

Thp chng ct: ti y cc phn on sn phm c tch ring theo ccu snphm ca nh my.

Hnh 1.1: Scng nghFCC




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1.2.3. Cng nghRFCC ca NMLD Dung Qut

Hin nay cng nghRFCC tiu biu c sdng nh my lc du Dung Qut

l cng ngh R2R_l cng ngh ca hng IFP Total v Stone & Webster. Haihng cng nghip ny hp tc tht kcng nghRFCC vi cm ti sinh xc tc2 cp. Qu trnh nhm cracking xc tc cn nng v c tn l R.2.R Process.Cng nghny c ci tin tcng nghFCC p dng cc kthut mi sau:

S dng hai tng ti sinh xc tc: m bo xc tc c ti sinh hon ton vkhng bph hy nhit cao.

Tng ti sinh thnht: xc tc c t cc iu kin thiu oxi v nhit thp. Ti y, nc bc hi phn ln nhng nhit thp nn khng th

kt hp vi Vanadi to ra axit Vanadic ph hy cu trc zeolite. Hiu sutt cc tng 1 l 70%.

Tng ti sinh thhai: xc tc c t cc iu kin doxi v nhit cao, hiu sut cc l 100%. Tuy nhin, lng hi nc cn li rt t nn xctc khng bph hy. Cc cn li bm trn xc tc c t trit trckhi a sang thit bphn ng.

Hnh 1.2: Scng nghR.2.R ca hng IFP Total v Stone & Webster




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S dng h thng khng ch nhit MTC (Mix Temperature Control) nhmmc ch khng chnhit m bo ha hi nguyn liu hon ton (94%) tng

hiu ququ trnh cracking.Hthng xl khCO, NOx, SOxcho kh thi m bo tiu chun kh thi vomi trng.

S dng thit b tch nhanh xc tc ra khi hn hp sn phm RTD (RiserTemperature Device).

1.2.4. Csl thuyt ca qu trnh cracking xc tc

Nhn chung, cc phn ng xy ra trong qu trnh cracking xc tc l phn ng thunhit v tng sphn t. Do , cc phn ng xy ra thun li iu kin nhit

cao v p sut thp[1].Nhng iu kin cng nghca qu trnh:

T = 470 550oC P = 1,5 2,5 bar tng i Khng c mt ca H2trong mi trng phn ng v H2lm gim nhanh hot

tnh ca xc tc.

1.2.4.1.Cchphn ng: l cchioncacboni

Cc tm hot tnh l ion cacboni c to ra khi cc phn t hydrocacbon canguyn liu tc dng vi tm axt ca xc tc.

Tm axt xc tc c 2 lai:

Tm Bronsted (H+): c khnng cho proton H+ Tm Lewis (L): c khnng nhn cp electron

Shnh thnh tm axit Bronsted[2]:Cc nhm -OH tn ti trong cu trc zeolite l do sau khi trao i cation v phn

hunhit.

Tqu trnh xl zeolite trong mi trng axit.

Strao i cation ca zeolite vi cc cation a ha tr(nhkim loi kim th, t

him).




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Shnh thnh cc tm axit Lewis:Shnh thnh tm axit Lewis l do tn ti Al trong mng cu trc. Khi nguyn t

oxy btch ra nhit cao khi lin kt vi Al th sxut hin tm axit Lewis.

Axit Bronsted Axit Lewis

Phn ng cracking xc tc xy ra theo cc giai an sau:Giai an 1: giai on khi mo to ion cacboniV d: Trong trng hp i vi cc hydrocacbon mch thng (Ankan):

Giai an 2: giai on pht trin mch cc phn ng ca ion cacboni to ccsn phm

Khi cc ion cacboni c to ra slp tc tham gia vo cc phn ng bin i khcnh:

Phn ng ng phn ha.

Phn ng ct mch theo quy tc (ct mch vtr so vi cacbon mang intch).

Cc ion tip tc tham gia cc phn ng ng phn ha, ct mch tip, ankyl hahay ngng t. Bin i cc ion cacboni tip din cho n khi c cu trc bn vngnht.

bn ca cc ion cacboni c thxp xp theo tht:

Ion cacboni bc 3 > Ion cacboni bc 2 > Ion cacboni bc 1




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Giai on 3: giai on dng phn ngKhi cc ion cacboni kt hp vi nhau, nhng hay nhn nguyn thydro ca xc

tc to thnh phn ttrung ha v chng chnh l cu tca sn phm crackingxc tc.

1.2.4.2. Cc phn ng chnh ca qu trnh FCC

Parafin bcracking cho olefin v cc parafin nhhn[3].CnH2n+2 CmH2m+ CpH2p+2 (1-1)

Olefin bcracking cho olefin nhhn.CnH2n CmH2m + CpH2p (1-2)

Cc ankyl hydrocarbon aromat (cc hydrocacbon vng thm vit tt lArCnH2n+1, trong Ar: gc hydrocacbon aromat, CnH2n+1 l gc ankyl) bcracking cho aromat v olefin.

ArCnH2n+1 ArH + CnH2n (1-3)

Thay v phn ng dealkyl ha, phn ng cracking mch nhnh ca vngthm c thxy ra.

ArCnH2n+1 ArCmH2m-1 + CpH2p+2 (1-4)

Cc hydrocacbon aromat khng c nhm th tng i kh b cracking iu kin cng nghip v sbn vng ca cc vng thm.

Cracking naphten (xycloparafin) to ra cc olefin.CnH2n CmH2m + CpH2p (1-5)

Nu parafin mch nhnh c cha mt vng xyclo hexan th vng khng bph v.

CnH2n C6H12 + CmH2m + CpH2p (1-6)

Cc phn ng thcp xy ra tip sau cc phn ng scp ng mt vai trquan trng trong vic xc lp thnh phn sn phm cui cng trong qu trnhcracking.

Cc phn ng thcp thng l: Chuyn dch hydro

Naphten + Olefin Aromat + Parafin (1-7)Tin cht cc aromat + Olefin Cc + Parafin (1-8)

Isome haOlefin Isoolefin (1-9)

Chuyn dch nhm alkylC6H4(CH3)2 + C6H6 C6H5(CH3) + C6H5(CH3)

Phn ng ngng t(condensation reactions)




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(1.10)

1.3. Nguyn liu

1.3.1. Nguyn liu sdng cho qu trnh FCC

Nguyn liu cho qu trnh cracking xc tc thng c khong nhit si t300-500oC, c thtcc ngun nhsau[4]:

Phn ct nhca qu trnh chng ct kh quyn ca du th (DA) c khongnhit si 380-410oC.

Phn on cn chng ct chn khng vi khong nhit si 380-550oC. Phn ct tqu trnh cc ha hoc gim nht. Cn gudron tch nha asphalten (>550oC). Cn chng ct kh quyn (> 380oC) ca vi loi du th.

1.3.2. c trng vnguyn liu

Vic xc nh r cc tnh cht c trng ca tng loi nguyn liu m bo svn hnh n nh ca phn xng FCC l mt nhim v rt quan trng. T,ngi ta c thla chn cht xc tc, xl cc sc, ti u ho qu trnh cracking

xc tc.Cc yu tquan trng nht nh hng n cht lng ca nguyn liu FCC l

cc hydrocacbon v cc tp cht cha trong nguyn liu FCC.

1.3.2.1. Phn loi cc hydrocacbon

ParafinParafin l cc hydrocacbon mch thng hoc mch nhnh c cng thc ho hc l

CnH2n+2[3].

Ni chung, nguyn liu FCC thng cha chyu cc hydrocacbon parafin. Hmlng ca cacbon trong parafin chim khong 50 n 65% khi lng ca nguynliu. Parafin dbcracking v to ra lng sn phm lng nhiu, nhng c gi troctan thp.

OlefinOlefin l cc hydrocacbon cha bo ho, c cng thc l CnH2n. So vi parafin,

olefin l hp cht km bn hn v c thphn ng vi nhau hoc vi cc cht khcnhoxy, v vi dung dch brom. Olefin khng tn ti trong du mtnhin, n c




19/82


mt trong nguyn liu FCC l do cc qu trnh xl trc , v dnhdo crackingnhit, hoc do cracking xc tc...

Olefin khng phi l hp phn mong mun trong nguyn liu FCC v olefinthng bpolyme ho to ra cc sn phm nhcc v nha.

NaphtenNaphten c cng thc CnH2n cng nhcng thc ho hc ca olefin. Olefin c

cu trc mch thng (chnh xc hn l mch h), cn naphten l parafin c cu trcmch vng. Naphten l hp cht bo ho. V d, cc naphten nhxyclopentan,xylcohexan, metyl-xyclohexan c cu trc vng nhsau:

Naphten l hp phn mong mun trong nguyn liu FCC v chng to ra xng cgi troctan cao. Xng c to ra tnaphten c nhiu aromat hn, v nng hn sovi xng c sn xut tcracking parafin.

AromatAromat (CnH2n-6) tng tnhnaphten, nhng cha vng cacbon cha bo ho

v kh n nh. Aromat l cc hp cht cha t nht mt vng benzen. Vng benzenrt bn v khng bcracking. Cc aromat l hp phn mong mun cho nguyn liuFCC hin nay, v sto ra xng c gi troctan cao.

Cracking cc aromat thng xy ra s phn ct cc mch nhnh v to ra cchydrocacbon phn tnh. Ngoi ra, mt sthp cht aromat a vng c thto ranhng mng cacbon nm li trn bmt cht xc tc (cc), hoc cc sn phm aphn tkhc (nha).

Nguyn liu cng nhiu hp cht thm th chuyn ha s thp hn v gimhiu sut to xng, C3, C4 cn hiu sut LCO, HCO, cn y, cc v kh kh thtng. Trsoctan ca xng tng khi nguyn liu cha nhiu aromat.

1.3.2.2. Cc tnh cht vt l ca nguyn liu FCC

Ttrng, oAPITtrng (density, D) l mt i lng o mt cht lng: D ca cht lng l

tsca trng lng mt thtch cht lng vi trng lng ca thtch nc tngng, ti mt nhit cho, v dnhit 15,5oC. oAPI l i lng o mt

ca hydrocacbon lng[3].




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Gia D15,5 voAPI c mi lin hsau y:

AI =141,5

D, 131,5

V mt tnh theo oAPI tlnghch vi ttrng D, nn oAPI cng cao th ducng nh.

Cng mt khong nhit chng ct nhnhau, phn on c oAPI cng cao thd b cracking hn, v nguyn liu c oAPI cng cao th c nhiu parafin mchthng di hn. Khi tip xc vi cht xc tc nhit ~700oC, chng dbphnct thnh cc sn phm c gi tr.

im anilinAnilin l mt amin thm (C6H5NH2). Anilin c s dng xc nh hm

lng cc hydrocacbon thm ( aromat) ca cc sn phm du m, trong cnguyn liu cho FCC. im anilin (AP) l nhit ti thiu ho tan hon tonmt mu du vo anilin.

AP tng vi stng hm lng parafin (parafin) v gim vi aromat. imanilin cng tng theo trng lng phn t.

Chskhc xTng t nhim anilin, ch s khc x (RI, refractive index) cho bit hm

lng aromat ca mu. RI cng cao, aromat cng nhiu v mu cng kh bcracking. Mt mu c RI bng 1,5105 bcracking kh hn mu RI 1,4990. Chskhc xc o bi phng php thc nghim (ASTM D-1218) hoc c xcnh theo quan hchuyn i theo hthc TOTAL tAP. Trong phng th nghim,ngi ta o RI bng khc xk. i vi nhng mu du c mu ti v nht cao,cAP v RI u bhn chvchnh xc v khnng sdng.

nht nht biu th thnh phn ho hc ca mt mu du. Khi nht ca mutng, hm lng parafin tng, hm lng hydro tng v hm lng aromat gim.

nht c o hai nhit khc nhau, thng 38oC v 99oC. i vi nhiunguyn liu FCC, mu du kh c v st 38oC nn mu c gia nhit khong50oC.

nht l mt thc o bn chy ca mt cht lng. n vo nht tuyti l poise (P). Song vic xc nh nht tuyt i thng khng n gin, do, ngi ta thng s dng nht ng (kinematic viscosity). nht ng




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Sngc xc tc do cc hp cht nitkhc trong nguyn liu FCC l kh ln.Ngi ta bit rng, 100 ppm nitdng baztrong nguyn liu lm gim khong 1%

hiu sut xng. khc phc tc hi ca hp cht nitbaz, ngi ta phi nng caonhit phn ng v sdng cc cht xc tc c hm lng zeolite cao v pha nnhot tnh.

Ngoi ra, hp cht nitcn c tc dng xu i vi mt sbphn khc. Chnghn, trong reactng ng (riser), hp cht nitc th chuyn thnh amoniac vxyanid (HCN) gy n mn ca cc thit btrong phn xng kh.

Ngoi ra, mt shp cht nitcng c mt trong du nh (LCO) nhpyrol vpiridin. Nhng hp cht ny dboxy ho v slm i mu ca sn phm.

Ni chung, du th nng cha nhiu nithn du th nh. Ngoi ra, hm lngnitc khuynh hng gia tng theo phn cn trong du th.

Mt shp cht nittrong du th:

- Hp cht trung tnh

- Hp cht nitbaz

- Hp cht nitbazyu

Lu hunhNguyn liu FCC cha lu hunh di dng cc hp cht hu c sulfua nh

mercaptan, sulfua, disulfua v thiofen. Thng thng khi hm lng cn trong duth tng ln th hm lng lu hunh cng tng.

Trong qu trnh cracking FCC, H2S c hnh thnh chyu tphn ng phnhuxc tc ca cc hp cht khng cha vng thm.




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Sphn blu hunh trong cc sn phm FCC khc nhau phthuc vo nhiuyu t: ngun nguyn liu, kiu cht xc tc, chuyn ho v chvn hnh.

Cc hp cht lu hunh dng thiofen (dng vng) b cracking chm, v ccthiofen khng bcracking chuyn vo trong xng, du nhv du gn.

Qu trnh xl bng hydro lm gim lng lu hunh trong mi sn phm. Vinguyn liu c x l bng hydro, lng lu hunh trong nguyn liu c

chuyn vo cc v sn phm nng nhiu hn. Nguyn liu cng nng, cng giuaromat th hm lng lu hunh trong cc cng cao.

Mc du xl hydro lm tng hm lng lu hunh trong cc v trong cn nha,nhng lng lu hunh thc tt hn ng kso vi lng lu hunh trong nguynliu cha xl. Lu hunh khng nh hng n nhit chuyn ho v hiu sutsn phm.

1.3.2.4. Cc kim loi

Cc kim loi nhniken, vanadi v natri c trong du th.Cc kim loi ny l cht

xc tc v trxc tc cho nhiu phn ng khng mong mun, nhdehydro ho vngng t, lm cho hiu sut hydro v cc tng ln v hiu sut gasolin gim. Kimloi lm gim hot tnh xc tc i vi cc sn phm mong mun.

Hu nh tt ccc kim loi trong nguyn liu FCC u bgi li trn cc chtxc tc cracking. Nguyn liu giu parafin cha nhiu niken hn vanadi. Mi mtkim loi c mt tc hi nht nh[3].

NikenNh bit, cht xc tc cracking cng nghip c hai phn chyu:

- Pha hot ng xc tc l zeolite Y.- Cht nn: chyu l khong st, aluminosilicat v nh hnh.

Khi tip xc vi cht xc tc, niken lng ng trn pha nn. Niken trxc tccho phn ng dehydro ho, tch hydro t cc hp cht bn v to ra cc olefinkhng bn. Cc olefin ny c thpolyme ho to ra cc hydrocacbon nng. Ccphn ng ny dn n hiu sut cao ca hydro v cc. Lng cc trn bmt chtxc tc tng lm cho nhit hon nguyn cao hn. Nhvy, cn gim tschtxc tc/du v do gim chuyn ho.




24/82


Hm lng niken cao l iu thng thy khi chbin nguyn liu nng. To ranhiu hydro hoc nhit hon nguyn cao l iu khng mong mun i vi cc

nh lc du.Ngi ta nhn thy rng, da vo s liu xc nh lng kim loi trn cht xc

tc lm vic n nh (cht xc tc cn bng) c thtnh ton lng kim loi trongnguyn liu mt cch chnh xc hn so vi sphn tch trc tip tnguyn liu.Nu niken l kim loi thng xuyn c mt trong nguyn liu, th c thsdngcht thng hn chnh hng ca niken. Thng thng, ngi ta s dngantimon thng ho niken. Bin php ny l khdnu hm lng niken trongcht xc tc cn bng ln hn 10.000 ppm.

VanadiVanadi cng l kim loi cho cc phn ng dehydro ho, nhng yu hn so vi

niken. Phn ng gp to ra hydro ca vanadi chbng 20% n 50% so vi niken.Khng ging niken, vanadi khng bgili trn bmt cht xc tc. Thc vy, ndi chuyn vo bn trong cht xc tc (zeolite) v ph hoi cu trc tinh th cazeolite. Bmt ring ca cht xc tc v hot tnh xc tc gim dn.

Vanadi c mt trong cc phn thu ckim loi (ckim) c phn tlng cao,khi nhng phn tnng ny bcracking, cn cc cha vanadi bgi li trn cht

xc tc. Trong qu trnh hon nguyn, cc b chy v vanadi c chuyn thnhoxyt vanadi V2O5.

V2O5nng chy 690oC v ph vcu trc tinh th zeolite. V2O5kh linh ng

nnc thdi chuyn tht tinh thny n ht tinh thkhc.

Hin nay, c mt vi l thuyt v ho hc ng c ca vanadi. Trong , lthuyt phbin nht cho rng, V2O5chuyn ho thnh axit vanadic (H3VO4) trongiu kin hon nguyn xc tc. Axit vanadic tch nhm tdin (Al) trong mng cutrc tinh thzeolite v do lm sp khung tinh th.

Tc dng ngc ca vanadi phthuc vo cc yu tsau y:- Nng vanadi: ni chung, nng vanadi trn 2.000 ppm trong cht xc tc

cn bng cn p dng bin php thng ho hn chtc hi ca vanadi.- Nhit thit bhon nguyn xc tc: nhit thit bhon nguyn cht xc

tc (>677oC) vt qu im nng chy ca oxyt vanadi lm gia tng khnnglinh ng ca V2O5di chuyn n cc tinh thzeolite.

- Cch t chy cc: cht chy cc hon ton to ra cht xc tc "sch"lm tng shnh thnh V2O5v nhc mt oxy d.




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mt xc tc dn n ssuy gim hot tnh cht xc tc. Do vy, hon nguynhot tnh ca xc tc, ngi ta phi t chy cc trong thit b hon nguyn

(regenerator). Tuy nhin, cc l mt sn phm phcn thit cho shot ng cacng on FCC, bi v nhit sinh ra tphn ng t chy cc c cung cp chophn ng cracking-phn ng thu nhit.

1.5. Xc tc FCC

1.5.1. Cu trc xc tc FCC

Xc tc FCC bao gm hai hp phn chnh l zeolite v cht nn (matrix). Ngoira cn c thnh phn khc nh cht n v cht kt dnh. Zeolite chim 1050%khi lng ca xc tc. Cht nn chim phn tlcn li, bao gm cc thnh phn:t st, nhm hot tnh v cht kt dnh.

Hnh 1.3: nh chp SEM ca ht xc tc

Hnh 1.4: Cu to ht xc tc




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Hnh 1.5: Cu to cszeolite

Cu trc c bn ca tinh th zeolite l t din (tetrahedron) to bi Al, Si, O.Tm tdin l mt nguyn tSi hay Al, 4 nh l 4 nguyn tO. Cc tinh thhp li thnh mng khng gian. Mng khng gian zeolite c cc lrng (pore) ckch thc khong 8.0 Angstroms. Nhng l rng lm cho din tch bmt ringca zeolite rt ln, khong 600m2/g[5].

1.5.2. Thnh phn xc tc FCC

1.5.2.1. Pha hot tnh Zeolite

Zeolite cha t10 n 50% khi lng ht xc tc v quyt nh chnh n khnng cracking ca xc tc, hiu sut sn phm xng, LPG.

Hin nay c nhiu loi zeolite c bit n v sdng vi nhiu mc ch khcnhau. Trong cng nghlc du, phn ln xc tc FCC sdng zeolite kiu Y.

Zeolite dng Y

y l cc aluminosilicat tinh thngm nc. Cng thc phn tca zeolite Y:NaOx[(AlO2)x(SiO2)y].zH2O. (y/x 2)[5].

Hnh 1.6: Hnh dng zeolite




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Zeolite loi Y c khung tinh thba chiu to thnh cc tdin [SiO4] hay [AlO4].Cc tdin ny skt hp vi nhau theo nh. Lin kt Si O Al to thnh

cc lxp trn bmt c ng knh cnh cng cc hc, knh c kch thc t4 8 , chnh cc hc c thcha cc cation b trv cc phn tnc. Cc cationny d dng c trao i v c a ra khi zeolite hnh thnh tnh axit cazeolite.

1.5.2.2. Cht nn

Pha nn cha tt nht l 2 hp phn: mt l cht kt dnh, thng thng l ccoxyt tng hp nhoxit silic, oxyt nhm, aluminosilicat v nh hnh,...; hai l vtliu khong st, thng l cao lanh. Khong st to nn bn chc ca ht xc

tc c rt t hoc khng c hot tnh nhng li ng vai tr ti nhit rt tt. Cn oxyttng hp c vai tr kt dnh cc thnh phn ca xc tc.

Cht n l loi t st thm vo xc tc lm long hot tnh ca n. Cao lanhthng c sdng lm cht n ca xc tc FCC. Ngoi ra, cao lanh cn csdng lm bkhung pht trin cc tinh thZeolite trn n.

Cht kt dnh gip gn kt zeolite, cht mang v cht n vi nhau.

Chc nng ca cht n v cht kt dnh l m bo tnh bn vt l ca xc tc,m bo mi trng khuch tn nhit.

1.6. Zeolite ZSM-5

1.6.1. Cu trc zeolite ZSM-5

Cu trc zeolite ZSM-5 bao gm 10 nguyn toxy lin kt vung gc vi nhautheo kiu zic-zac to thnh mt cu trc lxp ba chiu. ng knh lxp l0.56 nm x 0.53 nm theo khe thng v 0.55 nm x 0.51 nm theo chiu ngang nn kchthc l xp ca ZSM-5 nhhn so vi zeolite Y (cu to t 12 nguyn toxy,ng knh lxp l 0.74 nm x 0.74 nm)[6].

Hnh 1.7: Cu trc tinh thzeolite Y v ZSM-5




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1.6.2. Thnh phn ha hc ca ZSM-5

Cng thc ha hc ca ZSM-5 c dng:

NanAlnSiO96-nO192.~16H2O (n < 27) (1.11)Da vo cng thc ha hc ca zeolite ZSM-5 ta thy thnh phn ha hc ca n

bao gm cc nguyn t: Na, Al, Si, O v H. Chng tn ti di dng oxit kim loi(Al2O3, SiO2, Na2O) ngm nc. Cc oxit ny chim gn nh ton bkhi lngca zeolite, ty vo tnh cht ca zeolite m tlmi oxit khc nhau.

m bo hot tnh v bn ca zeolite trong iu kin lm vic khc nghit,nh sn xut thm mt lng pht pho vo xc tc di dngH3PO4hoc NH4H2PO4. Cc th nghim ca Blasco vvic thm pht pho vi nng

khc nhau vo xc tc. Kt qucho thy, khi thm P vo xc tc slm n nhkhung nhm ca zeolite ZSM-5 v hn ch qu trnh thy nhit. T l pht phothm vo ti u khi tsP/Al = 0,50,7. Khi pht pho c bsung vt qu slng ti u, khung nhm c n nh nhng lm gim tnh axit v hot tnh mtcch ng k[7].

1.6.3. Tnh cht ca zeolite ZSM-5

Tnh cht ca zeolite ZSM-5 thay i theo theo thnh phn vi tsSi/Al. Cc

tnh cht nh

trao

i ion, tnh k

n

c, tnh cht xc tc tc thay

i h

u nh

tuy

ntnh vi hm lng nhm, trong khi tnh cht k nc th ngc li. Cc tnh

cht vt l nh: cu trc tinh th, thtch mao qun, mt tinh th, khng phthuc vo tsSi/Al[3].

1.6.3.1. Tnh axit

dng proton, H-ZSM-5 c cc tm axit Bronsted v cc tm axit Lewis. Nngca cc tm axit Bronsted mnh t lvi nng ca Al trong mng tinh th.Khi tng nhit nung ZSM-5 n 400oC dn n qu trnh tch nhm hydroxyl (-

OH), lm gim cc tm axit Bronsted v tng cc tm axit Lewis. Qu trnh xlnhit-hi nc hn hp ZSM-5/Al2O3 lm tng hot tnh xc tc tc cracking vkhnng trao i ion ca zeolite[3].

1.6.3.2. Tnh cht chn lc hnh dng

Tnh cht chn lc hnh dng l yu t then cht lm gia tng chsoctan caxng khi ZSM-5 c sdng lm cht phgia cho cht xc tc cracking FCC.

Tnh cht chn lc hnh dng xut pht tkhnng hn chkch thc v hnhdng cc phn tkhuch tn vo v ra khi knh mao qun ca zeolite.

Tnh cht chn lc hnh dng bao gm[8]:




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Chn lc theo cht phn ng: loi bcc phn ttham gia phn ng c kchthc ln hn kch thc ca smao qun ca zeolite.

Chn lc theo sn phm phn ng: chnhng sn phm phn ng c hnhthnh phi c kch thc nh hn kch thc mao qun zeolite th mikhuch tn c ra ngoi tinh thzeolite.

Chn lc theo trng thi trung gian: nhng phn ng thc hin qua nhngtrng thi khng gian cng knh, c kch thc ln hn kch thc mao qunth khng xy ra, chu tin cho cc phn ng xy ra qua cc trng thi trunggian kch thc nh.

1.6.3.3. TlSi/Al

Zeolite ZSM-5 l zeolite c hm lng oxyt silic cao(tsSiO2/Al2O3c thbini trong khong rng t20 n 8.000), cao hn nhiu so vi zeolite Y (22,43 >3,28). Nh ni mc 1.6.3 v 1.6.3.1, t lSi/Al trong zeolite ZSM-5 cao lmmt axit gim, kch thc lxp gim. Do , gim phn ng to cc v khnng thc hin phn ng chuyn dch hydro gia hai phn t. T l Si/Al trongzeolite ZSM-5 cao cng ng ngha vi bn thy nhit ca zeolite ZSM-5 cngcao hn.




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Bng 1.1: Thnh phn ha hc ca zeolite Y v H-ZSM-5[9]

Thnh phn zeolite Y zeolite H-ZSM-5

Al2O3, %kl 23,00 4,20SiO2, %kl 75,50 94,20

Na2O, %kl 0,61 0,49

1.6.3.4.bn thy nhit

Trong qu trnh phn ng, cc hnh thnh (do phn ng ngng t) v kim loi (ctrong nguyn liu) bm ln bmt xc tc. ti sinh xc tc, cc c t tronghai thit bti sinh. Qu trnh t chy sinh ra hi nc, COx, SOx, ... ng thi tara mt lng nhit ln. Nhit sinh ra trong bung ti sinh th cp c tht n810oC[7, 10]. Chnh sc mt ca hi nc nhit cao cng kim loi vanadi stch nhm v ph hy cu trc zeolite.

Do , m bo hot tnh v bn ca zeolite trong iu kin lm vic khcnghit nhtrn, nh sn xut thm mt lng pht pho vo xc tc nhm trnhhin tng tch nhm tng bn cho xc tc.

1.6.4. nh hng ca ZSM-5 n hiu sut propylen, trsoctan ca xng vccu sn phm ca qu trnh FCC

1.6.4.1.nh hng ca ZSM-5 n hiu sut propylen

Hnh 1.8: nh hng ca xc tc n sn phm ca phn xng FCC

Qua hnh trn ta thy, nu sdng xc tc csth lng propylen thu c phthuc vo qu trnh cracking trn xc tc chnh (1). Khi thm phgia ZSM-5 vo

trong xc tc cracking th hiu sut propylen thu c nhiu hn do lng olefin




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nh(nhC6=, C7

=, C8=) trong phn on xng bbgy to thnh cc olefin nhhn

(chyu l propylen v butylen). Hn na, phgia ZSM-5 c t lSi/Al cao hn

xc tc FCC thng thng nn hot tnh chuyn dch hydro gim dn n chnlc olefin cao sci thin hiu sut propylen. Cc phn ng cracking cc olefin C6-C8xy ra theo cc phn ng chnh di y[6]:

1.6.4.2.nh hng ca ZSM-5 n sgia tng trsoctan ca xng

Vic bsung ZSM-5 cho phn xng cracking xc tc tng si (FCC) trong ccnh my lc du c p dng rng ri nhm tng chsoctane xng v sn xutthm cc olefin nhtuy nhin li lm gim hiu sut thu xng (theo bo co kt quca Miller v Hsieh da th nghim so snh gia hai loi xc tc sdng phgiaZSM-5 c tsSi/Al l 40:1 v 525:1)[11].

Vi kch thc l xp t 5,1- 5,6 , ZSM-5 ch cho php cc phn thydrocarbon c kch thc < 5,6 (cc parafin, olefin mch thng hay mch nhnhyu) i qua v cracking chng thnh cc phn t nh hn (cc parafin v olefinnh). ng thi, n khng cho php cc phn tcng knh nhcc parafin nhiumch nhnh, naphten v aromat i qua nn chng khng bcracking. Sn phm thuc gm olefin tng ln, parafin c nhiu mch nhnh v aromat khng bcracking l hp phn lm tng chsoctan ca xng.

1.6.4.3.nh hng ca ZSM-5 n ccu sn phm ca qu trnh FCC

Phgia ZSM-5 chlm thay i hiu sut thu sn phm khng lm thay i ccu sn phm FCC. Cthl tng hiu sut thu kh, c bit l olefin (propylen vbutylen) nhng hiu sut thu xng li gim.

Theo kt qunghin cu ca Aitani th ZSM-5 bgy cc olefin trong phn onxng trc khi xy ra cc phn ng chuyn dch hydro, ngthi tngcngccphnng isome ha cc olefin lm tng hiu sut propylen v lmgim hiu sut xng. Trong khi , khng c thay i ln vi hiu sut ca LCO,HCO, v cc[12].




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CHNG 2: THC NGHIM

Quy trnh thc nghim ca ti c m ttheo hnh di y:

Hnh 2.1: Squy trnh thc nghim ca ti

2.1. i tng thc nghim

2.1.1. Nguyn liu

Nguyn liu sdng cho ti gm 4 loi nguyn liu A1, A2, P1 v P2.

Xc tc Phgia

Gimho t tnh

Thit b

MATNguyn

li u

SIMDISTGC GAS LECO GC 7890

KT QU

PHN TCH

NH GI




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Bng 2.1: Mt stnh cht v thng squan trng ca nguyn liu

Tnh cht cn du RFCC A1 A2 P1 P2

Khi lng ring 15oC, g/ml 0,910 0,898 0,918 0,916

oAPI 23,80 25,90 22,60 22,90

Hm lng Cn Cacbon, %kl 0,23 0,06 2,03 4,37

Hm lng Asphalten, %kl 0,179 0,015 0,842 0,280

Hm lng Nha, %kl 8,142 0,251 6,289 12,620

Hm lng Parafin rn, %kl 13,13 24,29 42,79 35,56Hm lng Vanadi, ppm -


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V, ppm 327 0

Na, %kl 0,13 0,06

RE2O3, %kl 1,14 0,99

Al2O3, %kl 55,30 56,35

Kch thc mng cs, 24,29 24,57

Thtch lxp, cc/g 0,18 0,25

Kch thc lxp, 88,23 40,00

0-20m, %kl 0,57 3,11

0-40m, %kl 7,15 18,130-80m, %kl 67,8 77,11

Kch thc ht trung bnh, m 72,22 62,8

Chsmi mn 3,00 4,85

2.1.3. Phgia

Phgia sdng trong ti l loi phgia X l mt loi phgia ZSM-5 thngmi, mt stnh cht ha l quan trng ca phgia mi c thhin trong bng

2.3 di y.Bng 2.3: Mt stnh cht ca phgia mi X

Tnh cht Gi tr

Din tch bmt, m2/g 159,56

Din tch bmt zeolite, m2/g 136,59

Tldin tch Ze/Mx 5,9

ZSM-5, %tinh th 50

P2O5, %kl 8,88

Al2O3, %kl 24,02

Thtch lxp TB, cc/g 0,09

Thtch lxp vi mao qun, cc/g 0,053

Kch thc ht TB, m 77,89

Chsmi mn 1,2




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2.2. Phng php thc nghim

2.2.1. Xc nh hot tnh v chn lc ca xc tc FCC

2.2.1.1.Nguyn l phng php

Mt lng cn du c bm vo ng phn ng v tip xc trc tip vi lp xctc tng cnh trong thi gian v nhit nht nh. Sn phm phn ng gm bapha kh, lng v rn c phn tch thnh phn thng qua cc thit bsc k kh GCGAS, thit bsc k chng ct m phng SIMDIST v thit bhng ngoi LECO.

Hot tnh xc tc c nh gi da trn phn trm khi lng chuyn ha canguyn liu.

2.2.1.2. Thit b, tiu chun

Thit b s dng: SR-SCT-MAT (Single Receiver-Short Contact Time-Microactivity Test) ca hng Grace Davison.

Phn tch theo tiu chun: ASTM D5154-nh gi hot tnh v chn lc xctc FCC bng thit bMicroactivity test.

Hnh 2.2: Sthit bMAT




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2.2.1.3. Phng php thc nghim

Cn du c gia nhit 80oC chy long ng nht. Ly chnh xc 1,75 g

du ng thi np thm 03 ml kh N2vo xylanh bm. Hn hp nguyn liu nyc tip tc n nh nhit 80 oC trong vng 30 pht trc kh phn ng.

Cn chnh xc m g (phthuc vo tlxc tc/du) xc tc c sy kh nhit 540 0C trong vng 3 gi.

Thm mt lng cht n (ht thy tinh) c kch thc 180-200m ri trn u.

Np xc tc vo ng phn ng, lp xc tc nm gia hai lp bng thch anh (lpbng trn dy 6mm, lp bng di dy 20mm) cng vi li thp vo trong ngphn ng.

Bi mt lp graphit mng (graphite cho ng phn ng) ln lp ren ca ng phnng trnh chy ren ca ng phn ng nhit cao.

Lp ng phn ng vo l gia nhit, xc tc c n nh nhit 560oC trong 1,5gitrc khi phn ng.

Khi nhit ng phn ng t n nhit phn ng 482 oC, nhn nt TIMERSTART bt u phn ng, (chng trnh chy tng).

Sau khi chng trnh Timer kt thc, tho bnh cha sn phm lng, kh icn khi lng sau phn ng ri thu sn phm kh i phn tch bng GC GAS, snphm lng i phn tch bng SIMDIST. Thu xc tc trong ng phn ng phn tchhm lng cc bng LECO.

2.2.1.4. Xc nh kt qu

chuyn ha:chuyn ha= (%+ %)(2-1)

Hoc: chuyn ha= %klkh + %klxng+ %klcc(2-2)

Trong : %klLCO_phn trm khi lng ca phn on LCO

%klHCO_phn trm khi lng ca phn on HCO Hiu sut sn phm: l tlphn trm gia khi lng sn phm (kh, xng,

LCO, HCO, cc) trn nguyn liu, c tnh theo cng thc sau:

=

(2-3)

Trong : Yi: phn trm khi lng ca sn phm thi

Mi: khi lng ca sn phm thi

MFeed: khi lng nguyn liu




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thu hi: l phn trm tng cc sn phm thu c (kh, lng, cc) trnnguyn liu. thu hi cho php nm trong khong t95-102 %kl.

2.2.2.Gim hot tnh xc tc FCC bng phng php thy nhit2.2.2.1. Nguyn l phng php

Xc tc c lm gim hot tnh trong ng phn ng nhdng hi nc to cholp xc tc trng thi gisi. iu kin nhit cao v c mt hi nc, xc tcsbthy nhit mt nhm (dealuminated) v mt hot tnh.


Thit bsdng: thit bAM-1500 ca hng GRACE Davison.

Phn tch theo tiu chun: ASTM D4463-Phng php gim hot tnh xc tc mikhng c mt kim loi bng phng php thy nhit.

Hnh 2.3: Sthit bAM-1500

2.2.2.3. Phng php thc nghimCn chnh xc 120 g xc tc ( c nung loi m 205 oC trong 3 gisau

nng nhit ln 540 oC trong 4 gi) np vo ng phn ng.

iu chnh cp nhit in (thermocouple) vo trung tm lp xc tc.

Cp kh Nitthi ttrn ming l phn ng xung lp xc tc.

Gn ng ht bi xc tc vo st ming l phn ng.

Np nc ct vo bnh ng vch mc qui nh 500 ml.

Ci t thng svn hnh thit bgim hot tnh vn hnh theo quy trnh sau:




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Hnh 2.4: Sthi gian gia nhit ca phng php thy nhit

- Nng nhit cho lp xc tc:o Dng N2thi qua lp xc tc: 500 ml/pht din ra trong sut qu trnh.o Gia nhit cho reactor tnhit phng ln 538 0C (1.000 0F) vi tc 50

0F/pht.o Ginhit 538 0C (1.000 0F) trong 3 gi.o Gia nhit t538 0C (1.000 0F) n 1.5000F vi tc gia nhit 2 0F.o Ginhit 1.500 0F (816 0C) trong 1,2 gi.o Bm nc vo l vi tc 20 ml/h, sau 6 pht, dng cp kh nitthi qua

lp xc tc.- Thunhit: 100 % hi nc thy nhit 1.500 0F (816 0C) trong thi gian 12

h khng c N2thi qua.- Kt thc qu trnh, hnhit n nhit phng.Thu sn phm sau khi gim hot tnh:

- Ly l phn ng ra khi l gia nhit.- xc tc vo l, cn xc nh lng xc tc thu hi c.


t cc 500 oC trong 3 h, sau o cc chtiu khc nhhot tnh xc tc, SA(din tch bmt), UCS (n vkch thc mng), PSD (phn bkch thc ht).

2.2.2.5. Sai sca phng php

lch chun tng i ca php o c gi trl 2,6% (sliu c thng ksau 12 ln chy).




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2.2.4. Phn bkhong nhit si ca cc phn on lng du m

2.2.4.1. Nguyn l phng php

Phng php ny xc nh dy phn bim si ca phn on du mc nhitsi cui nhhn 538 oC. Cc hydrocacbon trong mu c hp phvo ct, sau ln lt c gii hp ph trong ct mao qun theo chng trnh gia nhit cact v c ghi li thnh phdi dng cc xung tn hiu. Nhit si ca cccu t mu c xc nh da vo thi gian lu v nhit si n-parafin chunc phn tch cng iu kin. Tkt quthu c, dy phn bnhit si caphn on c xc nh theo thut ton m phng.

2.2.4.2.Thit b, ti liu

Thit b sdng: my SIMDIST (Simulated distillation)-Thit b chng ct mphng.

Tiu chun phn tch: ASTM D2887


Xy dng ng cong chng ct chun:-Ly 0,5 ml chun n-parafin pha long vi 1ml dung mi CS2.-Lp phng php phn tch:

o Phng php phn tch mu chun n-parafin C5- C40D 2887 CAL .Mo Thit lp iu kin phn tch cho bphn bm mu tng.

-Tdliu thu c tphca phn mm Chemstation, lp ng congchng ct biu hin mi quan hgia thi gian lu v nhit si ca cccu tn-parafin.

Chy mu thc:-Pha long mu vi dung mi CS2theo 1 tlthch hp.

-Thit lp iu kin bm tng.-Da vo thi gian lu ca cc cu t c trong th vin mu chun, phn

mm Chemstation snh danh cc cu ttn ti trong mu phn tch.

-Sau phn mm Simdist dng thut ton m phng ra phn bim si ccphn on.


Cng thc xc nh nhit si cu ttrong mu phn tch:




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=

( ) + (2-7)

Trong : BPi_nhit si ca hp phn c phn trm im ct thi

RTi_thi gian lu ca hp phn c phn trm im ct thi

RT1_thi gian lu ca n-parafin chun lin ktrc RTi

RT2_thi gian lu ca n-parafin chun lin ksau RTi

BP1_ nhit si ca hp phn c thi gian lu l RT1

BP2_ nhit si ca hp phn c thi gian lu l RT2

Da vo tn hiu ng nn thu c tmu trng vi CS2, phn mm tin hnhtrtn hiu ng nn cho mu cn tnh ton.

2.2.5. Xc nh hm lng Cacbon, Lu hunh


Mu c t chy trong mi trng kh oxy tinh khit. Thnh phn cacbon ctrong mu c oxy ha thnh CO2cng vi mt lng nhCO. Thnh phn luhunh c oxy ha thnh SO2. Cc kh ny c lc tro bi v hi m trc khivo u d hng ngoi (SO2 IR cell) o hm lng ca lu hunh. Kh cn li tiptc qua hthng lc v chuyn ha thu CO2ri a qua u d hng ngoi (IR

cell) xc nh hm lng cacbon. Da vo nng lng hp thhng ngoi c chiudi bc sng xc nh ca CO2v SO2m phn mm SC600 tnh ton nng cacbon v lu hunh.


Thit bLECO phn tch hm lng cacbon, lu hunh.

Tiu chun p dng: ASTM E1915-Phng php phn tch qung kim loi v ccvt liu lin quan bng phng php hp thhng ngoi.

2.2.5.3 Phng php thc nghim

Chy mu trng (blank) lm sch hthng v n nh u d: Cho Lecocel vo chn nung v tin hnh phn tch. t chn nung ln b, nhn phm F5 my chy phn tch. Lp li qu trnh phn tch trn cho ti khi no kt qumu trng n nh

(thng chy 4 mu).Chy mu chun chun my:

Lp li qu trnh nh chy mu trng (blank) nhng cho cht chun vLecocel, Iron Chip vo chn nung trc khi tin hnh phn tch.

Cht chun Iron Chip c cn v nhp khi lng vo phn mm tnh ton.




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Chy mu cn phn tch: Mu c trn u trc khi phn tch. Lp li qu trnh nhchy mu chun nhng thay cht chun bng cht cnphn tch.


Sau khi phn tch mu ta c c din tch mi phcht cn phn tch. T davo phng trnh ng chun lp trong bc to phng php, lp ngchun trn ta tnh c nng cacbon, lu hunh trong cht cn phn tch.

Phng trnh ng chun: = + (2.8)

Trong : b_hsgc

a_gi trim ct trc tung

Analyte_nng cacbon/lu hunh trong cht cn xc nh

Area_din tch mi phca cacbon/lu hunh trong cht cn phn tch.

2.2.6. Xc nh trsRON v MON ca phn on xng


Cc cu t trong phn on xng thc hin qu trnh hp phv gii hp theochng trnh gia nhit ca ct mao qun. Sau , chng ln lt sphn tch ra v

c ghi li tn hiu xung bi u d ion ha FID cui ca ct. Mi cu tcxc nh bng cch so snh thi gian lu ca cu t trong th vin mu chun cng iu kin phn tch bng phm mm Hydrocarbon Expert. T kt qunhdanh v nh lng chi tit tng cu t, phn mm G-CON tnh ton xc nh trsRON, MON ca phn on xng trong mu lng FCC phn tch.

2.2.6.2 Thit b, tiu chun

My sc k kh GC 7890 ca hng Agilent.

Tiu chun p dng: ASTM D 6729-Xc nh tr s RON v MON ca phnon xng bng phng php sc k kh.


Pha mu: mu cn phn tch c pha long vi dung mi CS2 theo t l gnng 1:1.

Lp phng php chy. Xc nh phng php bng cch chy mu chun n-parafin C5-C15 ct

phn on carbon mong mun.




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o mu chun DHA, kim tra nng chun so vi thc t. Nu t yu custin hnh trn mu tht.

Lp cc vng lp (sequence) bm mu tng v chy tng. Vo menu SEQUENCE chn SEQUENCE TABLE v khai bo, lu

chn Back Injector v lu bng cch chn Save Sequence Template.

Khi trng thi Ready sn sng, chn Run sequence bt u chy mu tng.

Theo di tn hiu hin thtrn ca sInstrument Online.Ghi a chcc file thng tin ca mu chy vo file YELLOW BOOK qun l.nh danh cu tv nh lng trn phn mm HydroCarbon Expert.

Mbiu tng EDITOR (Pencil) to file xl nh dng *.HCD.

Khai bo thng s t l xng trong mu. Chn Configuration Recovery.Recovery c thc ly t kt qu phn tch ca thit b chng ct mphng SIMDIST D 2887 hoc tnh bng cch pha cht ni chun MEK votrong mu o.

Tip tc vo biu tng PROCESS chn phca mu cn xl, mkm file parameter va to trn v chn OK.

Load mt phca mu chun chun c trong csdliu ca phnmm HCE, bng cch chn trn thanh cng cLOAD SIGNAL, chn phchun ca loi mu cn phn tch.

Tin hnh x l ph: cc file lu tr sau khi x l trn HCE c lutrong C:\Chem32\Separationsystems\HCE4 gm: *.GIX, *.HCD, *.OCT,*.HCX.


Phn mm HCE s xut kt qu di dng Excel hoc ASCII file. D liu tASCII data s l d liu vo cho phn mm tnh ton GCON. Phn mm ny s

tnh ton hon thin li cc gi troctane ng cho cc cu tv sxut kt qudng Text (c trn Word, Notepad, Wordpad).

Da vo thnh phn, hm lng cc cu ttrong mu v dliu RON, MON cacc cu t. Phn mm stnh ton c RON v MON ca mu o.

2.2.7 Sai sca phng php

Tt c cc phng php thc nghim o hot tnh ca phgia (xc nh thnhphn kh cracking, phn bkhong nhit si cc phn on du m, xc nhhm lng cacbon-lu hunh, xc nh trsRON & MON ca phn on xng)

u c thc hin trn cng chuyn ha (77 %kl) v cng cc iu kin thc




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nghim khc nh (nhit , %kl phgia). T lxc tc/du sc iu chnhcho ph hp. Sai sca phng php MAT c tnh theo phng php thng k

vi tin cy ca kt qul 95% v c cng cng thc tnh sai snhsau:=

(2.9)

Trong : Yi_sai sca sn phm i

ZR_gi trtun theo phn phi chun vi tin cy 95% (ZR = 1,96)

_lch chun ca my

n_sln lm th nghim (n = 2)

Sai sca php o hot tnh xc tc, phgia trn thit bMAT-SCT bng 1,82

%kl.Sai s ca cc sn phm cng c tnh ton theo cng thc (2.9) v c th

hin bng 2.4 di y.

Bng 2.4: Tm tt sai sca cc sn phm

Sn phm

Gi trphn phi(tin cy 95%)

Z = 1,96

Sln

th nghim

n = 2

lch chunca php o

(%kl)

Sai s

(%kl)

Kh kh (C1-C2) 1,96 2 0,05 0,07

LPG (C3-C4) 1,96 2 0,33 0,46

Propylen 1,96 2 0,09 0,12

Xng 1,96 2 1,21 1,68

LCO 1,96 2 0,67 0,93

HCO 1,96 2 0,74 1,03

Cc 1,96 2 0,17 0,24

RON 1,96 2 0,29 0,40




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CHNG 3: KT QUV THO LUN

3.1. Kt quv nh gi i tng thc nghim

3.1.1. nh gi i tng thc nghim

3.1.1.1.nh gi nguyn liu

Da vo bng 2.1 ta c nhn xt sau:

Nguyn liu sdng trong ti l nguyn liu cn nng (khi lng ring 15 oC > 0,884).

Cbn loi nguyn liu sdng trong ti (A1, A2, P1 v P2) u thucloi du parafin. V vy rt d cracking cho sn phm nh v propylen cao.

Trong , hm lng parafin ca du P1 v P2 cao hn rt nhiu (hm lngparafin rn ln > 35 %kl, im anilin cao > 118 oC). C ngha l du A1 chm lng aromat cao nht nn kh b cracking nht n du A2, P2 v P1(du P2 c chskhc xcao hn du P1 nn kh bcracking hn).

Hm lng asphalten rt t (< 1 %kl). Nhng hm lng nha li kh cao,ring du A2 c hm lng nha v asphalten rt thp.

3.1.1.2.nh gi phgia

Da vo tnh cht ca phgia bng 2.3 ta c nhn xt sau:

Din tch bmt ca zeolite v cht nn ca phgia kh ln (ln hn so vixc tc).

Tldin tch Ze/Mx v hm lng tinh thzeolite ZSM-5 kh cao. Hm lng oxit pht pho chim tlcao (khong 9%kl) nhm mc ch tng

bn thy nhit cho phgia.

Hm lng oxit nhm thp (24%kl), thp hn nhiu so vi xc tc nn phgia c bn mi mn cao hn xc tc.

Th tch lxp trung bnh v th tch lxp vi mao qun rt thp, chbngmt na ca xc tc cn bng. Do kch thc lxp ca phgia nhhn xctc (5,1-5,6 so vi 8-9 ).

3.1.2. Kt quthc nghim




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Bng 3.1: Sl iu thc nghim ca nguyn liu A1 v A

Nguyn liu A1

Nng phgia, %kl 0 1 3 5 10 20 0 1

chuyn ha, % 76,08 76,76 77,01 77,44 76,76 76,32 75,10 76,57

H2, %kl 0,22 0,21 0,21 0,21 0,21 0,21 0,17 0,16

C2=, %kl 0,82 1,69 2,94 3,94 5,19 5,60 0,66 1,26

Propylen, %kl 6,54 11,69 13,62 14,40 13,41 12,00 6,11 11,21

C3=/C4

= 0,73 1,13 1,29 1,37 1,45 1,51 0,65 0,92

(C3+C4) Olefin, %kl 15,42 21,86 24,04 24,75 22,49 19,80 15,36 23,28 (C3+C4) Parafin, %kl 5,50 7,33 9,04 10,39 12,53 14,75 4,37 5,63

Kh kh, %kl 3,30 4,04 5,30 6,40 7,69 8,18 2,34 2,80

LPG, %kl 20,91 29,19 33,09 35,14 35,02 34,55 19,74 28,91

Xng, %kl 46,93 38,07 32,72 30,16 28,49 28,50 50,14 42,02

LCO, %kl 15,77 15,62 15,25 14,76 14,78 14,60 14,48 13,64

HCO, %kl 8,06 7,52 7,65 7,72 8,37 8,99 10,33 9,69

Cc, %kl 4,65 5,18 5,61 5,46 5,27 4,81 2,60 2,56

RON 92,70 94,30 95,10 96,10 97,50 99,20 92,68 93,55

Parafin, %kl/xng 4,13 4,22 4,52 4,49 4,21 3,81 4,20 4,47



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LCO, %kl 11,88 10,54 8,66 8,53 8,56 7,51 11,95 10,08

HCO, %kl 11,86 8,94 6,31 5,54 5,98 6,48 11,58 8,18

Cc, %kl 3,79 3,83 4,38 4,37 4,45 4,46 4,87 5,04

RON 91,28 91,48 92,28 92,65 94,22 95,49 89,52 90,81

Parafin, %kl/xng 7,08 7,06 8,50 9,18 9,30 9,26 7,73 8,43

Isoparafin, %kl/xng 19,51 21,33 19,71 19,93 17,92 18,63 24,80 20,58

Aromat, %kl/xng 34,24 24,04 24,66 27,85 36,64 41,38 21,96 23,16

Naphten, %kl/xng 7,35 3,92 2,95 2,63 2,75 2,41 4,73 3,35

Olefin, %kl/xng 31,82 43,65 44,17 40,41 33,40 28,32 40,78 44,48



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Khi nng phgia ln hn 5%kl ng ngha vi lng xc tc gim dn tigim chuyn ha ng thi lm gim hiu sut cc phn on nhnht l xng-nguyn liu cho phgia. Hn na, cc HC mch thng hoc nhnh hu nh b

cracking thnh cc hydrocacbon nhhn C5, C6. bgy cc phn tny i hinng lng ln hn nhiu so vi iu kin trong l phn ng FCC. V nhng l dotrn m hiu sut propylen v olefin gim[10].

3.2.2. nh hng ca nguyn liu n chuyn ha vi sc mt ca phgiaZSM-5

nh hng ca tnh cht parafin, aromat ca nguyn liu n hiu quca phgia ZSM-5 c thhin r rng nht qua chuyn ha.

Khi cha c phgia thm vo th chuyn ha ca bn nguyn liu gn bngnhau khong 75-76%kl (hnh 3.2).

0 5 10 15 20

74

76

78

80

82

84

86

88

A1

A2

P1

P2

ochuyenhoa(%k

l)

Ty le phu gia (% kl)

Hnh 3.2: nh hng ca nguyn liu v nng phgia n chuyn ha

Khi thm ph gia, nguyn liu giu parafin P1 v P2 c chuyn ha tng rtnhanh so vi nguyn liu giu aromat A1 v A2. Ti nng phgia 5%kl du P1v P2 tng 10 %kl trong khi du A1, A2 tng ch1-4 %kl. Skhc nhau ny l dodu P1, P2 c nhiu parafin nn cc HC trong phn on LCO v HCO bbgynhiu hn (cc HC parafin dbbgy hn cc HC aromat) lm gim nhanh hiusut LCO v HCO nn chuyn ha ca nguyn liu giu parafin cao hn[14].




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Tuy nhin, khi thm nng phgia t5-20%kl th chuyn ha ca nguynliu parafin (P1, P2) khng tng na do hiu sut LCO gim nhng b li hiu sutHCO tng. Nguyn liu aromat c xu hng gim do hiu sut LCO gim chm

hiu sut HCO tng nhanh.Hiu sut LCO gim chm v hiu sut HCO c xu hng tng nh(hnh 3.11 v

3.12). L do l khi nng phgia thm vo ln th lng xc tc chnh gim. Mxc tc chnh c pha nn hot tnh ng vai tr cracking cc phn t ln to ranguyn liu cho phgia. Phgia khng c khnng cracking cc phn t ln dokch thc l xp nh. Do , khi thm nng ph gia nhiu s lm gim chuyn ha tng ca qu trnh lm gim hiu sut thu cc sn phm nh v tnghiu sut sn phm nng.

3.2.3. nh hng ca nguyn liu n ccu sn phm vi sc mt ca phgia ZSM-5

3.2.3.1. Hiu sut kh kh

Hiu sut kh kh tng nhanh khi nng phgia 0-5%kl v sau tng chmdn khi tng nng phgia. tng ca hm lng kh kh kh ng u vimi nguyn liu, trong tng ca nguyn liu A1 cao hn hn 3 nguyn liucn li.

Khi thm 5%kl nng phgia th chn lc kh kh ca du A2, P1 v P2tng gp i (6n vso vi 3 n v0%kl phgia), du A1 tng 4 n v(hnh3.3).

Vi chn lc c tnh bng tsca hiu sut sn phm ca mt nguyn liuchia cho chuyn ha ca nguyn liu .




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0 5 10 15 20

2

4

6

8

10

12

A1

A2

P1

P2ochonloc

khkho(%kl

)


Hnh 3.3: nh hng ca nguyn liu v nng phgia n chn lc kh kh

Trong , hiu sut H2, metan khng thay i khi thm phgia. Hiu sut etantng khng ng k, chc hiu sut etylen tng (hnh 3.4). Nhvy, hiu sut khkh tng l do hiu sut etylen tng.

0% 1% 3% 5% 10% 20%

0

1

2

3

4

5

6

H2

C1

C2

C2=

Thanhphankhkho(%k

l)


Hnh 3.4: nh hng ca nng phgia n thnh phn kh kh ca nguyn liuA1




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Hydro, metan v etan ch yu c sinh ra t qu trnh cracking nhit v qutrnh cracking trn xc tc chnh nn hiu sut gn nhkhng thay i (nhit caqu trnh c khng chv xc tc khng thay i).

Hiu sut etylen tng l nhqu trnh cracking su cc olefin nhv tng chmdn khi tng nng phgia. Etylen tng cng do cracking cc nhnh alkyl trnhydrocacbon aromat.

Bng 3.3: So snh thnh phn kh kh ca nguyn liu A1 v P1

Nguynliu

Nng

phgia, %kl

H2

%kl

C1

%kl

C2

%kl

C2=

%kl

Kh kh%kl

A1

0 0,223 1,285 0,968 0,820 3,296

1 0,206 1,236 0,905 1,691 4,0383 0,205 1,245 0,908 2,944 5,302

5 0,207 1,291 0,962 3,938 6,398

10 0,206 1,253 1,041 5,189 7,689

20 0,211 1,213 1,153 5,603 8,180

P1

0 0,181 0,907 0,736 0,635 2,460

1 0,141 0,850 0,682 1,270 2,943

3 0,143 0,917 0,695 2,500 4,256

5 0,141 0,890 0,684 3,486 5,202

10 0,140 0,863 0,706 4,815 6,524

20 0,150 0,866 0,804 6,176 7,997

Thnh phn H2, metan v etan trong kh kh ca nguyn liu A1 cao hn nguynliu P1 v khng c sthay i nhiu khi tng nng phgia. Nhng thnh phn

etylen li thay i rt r rt, tng theo nng phgia thm vo v tng kh ucho chai nguyn liu (bng 3.3). iu ny chng thiu quca phgia l lmtng hiu sut etylen m khng phthuc vo tnh cht ca nguyn liu.

Hiu sut kh kh tng cao khi tng nng phgia c thnh hng n gii hnvn hnh ca thit bnn kh m trong NMLD. Tuy nhin nu etylen c tch thuhi lm nguyn liu cho ha du th c thgim ti c cho thit bny ng thicng lm tng li ch kinh tcho nh my.




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3.2.3.2. Hiu sut LPG

Ging nhchuyn ha, hiu sut LPG tng nhanh khi thm 0-5%kl phgia vc xu hng dng li khi nng phgia thm vo ln hn 5%kl (hnh 3.5).

5%KL nng phgia c hiu sut LPG cao nht. Hiu sut LPG tng 25 %kli vi nguyn liu P1, P2 v 15 %kl i vi nguyn liu A1, A2. Chng t:

Hiu quca phgia ZSM-5 l bgy cc HC nng thnh cc HC nh. Hiu quca phgia ZSM-5 i vi nguyn liu giu parafin cao hn hn so

vi du nhiu aromat.

0 5 10 15 20

20

25

30

35

40

45

50

A1

A2

P1

P2

LPG(%k

l)


Hnh 3.5: nh hng ca nguyn liu v nng phgia n hiu sut LPG

Hiu sut LPG tng l do tnh cht chn lc hnh dng ca zeolite ZSM-5 (ni mc 1.6.3.2) bgy cc HC mch thng hoc nhnh trong phn on xng thnh

propylen v cc olefin nhl thnh phn chnh ca LPG[15].Du giu parafin (P1, P2) c hiu sut LPG tng nhanh v nhiu hn du c

nhiu aromat (A1, A2). Skhc nhau l do cc HC parafin dbbgy hn ccHC aromat nn hiu sut LPG ca du giu parafin cao hn.




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0 5 10 15 20

2

4

6

8

10

12

14

16

A1

A2

P1

P2

T

ongC3+C4Parafin(%kl)


Hnh 3.6: nh hng ca nguyn liu v nng phgia n tng C3+C4parafin

Hiu sut HC parafin (propan v butan) tng nhanh khi nng phgia thp vtng gim dn khi tng nng phgia (hnh 3.6).

Tuy nhin hiu sut HC olefin (propylen, buten-1, buten-2, isobutylen) tngnhanh hn HC parafin khi nng phgia thp (0-5%kl). Cthl 5%kl nng phgia, hm lng parafin tng 4-5 %kl nhng hm lng olefin tng 8-12%kl ivi nguyn liu nhiu aromatA1, A2 v tng 20 %kl i vi nguyn liu nhiuparafin P1, P2 (hnh 3.6 v hnh 3.7).

Khi nng phgia tng (trn 5 %kl) th HC parafin vn tng vi tc chmhn cn HC olefin gim. L do l cc olefin dbcracking phn ng mt lngln to ra cc olefin nhchyu l C3

=v C4=nng phgia thp nn cc HC

olefin tng nhanh. Khi nng ph gia tng, ch cn cc HC parafin (kh bcracking hn) bbgy cho to ra mt phn tolefin v mt phn tparafin lmgim lng HC olefin, cc HC parafin th vn tng.




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0 5 10 15 20

14

16

18

20

22

24

26

28

30

3234

36

38

A1

A2

P1P2

TongC3+C4Olefin(%k

l)


Hnh 3.7: nh hng ca nguyn liu v nng phgia n hiu sut C3+C4olefin

TlC3=/C4

=tng khi nng phgia tng (hnh 3.8) ngay ckhi hiu sut tngC3

=v C4=gim xung (hnh 3.7). Khi nng phgia ln hn 5% th tlny vn

tng ln. Do nng phgia cao lm tng cc tm axit Bronsted mnh thc y qutrnh cracking su cc ion cacbonium C4

+ trn tm xc tc to etylen. Hm lngC4

=gim nn tlC3=/C4

=tng.




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Khi tng nng phgia trn 5%kl, hiu sut thu xng tip tc gim nhng vitc chm hn (chgim 2 %kl t30 %kl 5 %kl phgia xung 28 %kl khi thm20 %kl phgia).

nng 5 %kl phgia, hiu sut thu xng ca nguyn liu P1 v P2 gim 20 %klv gim 15-17 %kl i vi nguyn liu A1, A2. Chng tnguyn liu nhiu parafingim hiu sut thu xng nhiu hn nguyn liu nhiu aromat.

0 5 10 15 20

10

15

20

25

30

35

40

45

50

Hieusuatpropylen(%kl)

Xang

Olefin

Isoparafin

Hieusuatxang,IvaO(%

kl)


6

8

10

12

14

Propylen

Hnh 3.10: nh hng ca nng phgia n hiu sut xng, propylen v thnh

phn I, O trong xng ca nguyn liu A1

T0-5 %kl phgia, hiu sut propylen tng mnh tri ngc l hiu sut xnggim mnh (hnh 3.10). Thnh phn isoparafin, olefin trong xng gim nhng thnhphn olefin gim mnh hn. iu ny chng minh hiu quca phgia ZSM-5 l

bgy cc olefin trong xng thnh propylen lm hiu sut xng v olefin trong xnggim, hiu sut propylen tng.

Bng 3.4: Thnh phn PIONA trong xng ca nguyn liu A1

Nguyn liu A1

Nng phgia, %kl 0 1 3 5 10 20

Parafin(% kl)/xng 4,13 4,22 4,52 4,49 4,21 3,81




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Isoparafin(% kl)/xng 27,64 24,91 23,80 22,56 20,67 18,15

Aromat (% kl)/xng 38,79 45,42 49,98 53,04 58,17 63,40

Naphten (% kl)/xng 5,83 5,62 5,04 4,58 3,87 3,14Olefin (% kl)/xng 23,61 19,83 16,66 15,33 13,07 11,49

Hiu sut xng gim l do hiu sut isoparafin v olefin trong xng gim. Ccthnh phn khc nhparafin, naphten c gim nhng khng ng k. Aromat tngl do cc thnh phn khc gim (bng 3.4).

Nng ph gia thm vo ln (trn 5% kl), hiu sut xng, isoparafin, olefin

trong xng tip tc gim nhng vi tc rt chm. Tuy nhin hiu sut propylencng gim theo. L do l nng phgia ln lm gim lng xc tc chnh nnlm gim chuyn ha tng ca qu trnh ng thi gin tip lm gim hiu sutsn phm xng v cc thnh phn trong xng.

3.2.3.4. Hiu sut phn on LCO

0 5 10 15 20

6

8

10

12

14

16

A1

A2

P1

P2

LCO(%k

l)


Hnh 3.11: nh hng ca nguyn liu v nng phgia n hiu sut LCO

Hiu sut phn on LCO gim nhanh khi nng phgia thp v gim chmdn khi tng nng phgia.




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Khi thm 5 %kl phgia, hiu sut LCO gim 4 %kl i vi nguyn liu nhiuparafin P1, P2 v gim 1-2 %kl i vi nguyn liu nhiu aromat (hnh 3.11). iuny chng thiu quca phgia ZSM-5 l lm gim LCO bng cch bgy cc

HC nng thnh HC nhhn trong phn on kh. ng thi cho ta thy hiu quca nguyn liu nhiu parafin l d b cracking hn so vi nguyn liu nhiuaromat.

Chnh sgim hiu sut LCO gp phn lm tng chuyn ha chung ca qutrnh (mc 3.2.2).

Khi nng phgia ln (trn 5 %kl) th hiu sut LCO gim chm v c xu hngkhng gim na. Do lng xc tc gim ko theo hiu sut sn phm nng tng lnlm hn chsgim hiu sut LCO.

3.2.3.5. Hiu sut phn on HCO

0 5 10 15 20

5

6

7

8

9

10

11

12

A1

A2

P1

P2

HCO(%

kl)


Hnh 3.12: nh hng ca nguyn liu v nng phgia n hiu sut HCO

Tng tnhhiu sut LCO, hiu sut HCO cng gim khi c mt ca phgia nng thp. Nhng khi nng ph gia ln th hiu sut HCO c xu hngngc li l tng ln (hnh 3.12).

Hiu sut HCO gim khi c mt ca phgia t0-5 %kl v t gi tr thp nht nng phgia thm vo 5 %kl. Trong c skhc bit gia ngyn liu c thnhphn khc nhau. Nguyn liu giu parafin th hiu sut gim rt nhanh 6-7 %kl

(hiu sut gim hn mt na), nguyn liu nhiu aromat chgim 1-3 %kl. Nht l




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nguyn liu A, hiu sut HCO gim rt t chng tnguyn liu A1 rt nhiu aromatv t parafin. Nguyn liu cng giu parafin th hiu quca phgia cng cao. CcHC parafin dbcracking nn hiu sut HCO ca nguyn liu giu parafin gim

nhanh hn.Khi nng phgia ln trn 5 %kl, hiu sut HCO c xu hng tng nh. Do chuyn ha gim dn ti cc HC nng khng c cracking lm cho hiu sut phnon nng tng ln. u tin l stng ln ca HCO ri n LCO.

3.2.3.6. Hiu sut phn on cc

0 5 10 15 20

3,5

4,0

4,5

5,0

5,5

6,0

6,5

7,0

7,5

A1

A2

P1

P2

ochonlocsanphamcoc(%kl)


Hnh 3.13: nh hng ca nguyn liu v nng phgia n chn lc snphm cc

Da vo chn lc sn phm cc ta nhn thy hm lng cc gn nhkhngthay i khi c mt ca phgia nhng nng khc nhau. Ring vi nguyn liuA1 v A2 th c schnh lch trong khong nng phgia thp t0-5%kl. Song,schnh lch vtrsl khng ng k.




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3.2.4. nh hng ca phgia ZSM-5 n trsoctan ca xng cracking

3.2.4.1. Sthay i trsoctan ca xng

0 5 10 15 20

88

90

92

94

96

98

100

A1

A2P1

P2

RON


Hnh 3.14: nh hng ca nguyn liu v nng phgia ntrsoctan ca xng

Trsoctan ca xng tng khi tng nng phgia. tng ca RON tuyn tnhvi nng phgia thm vo (hnh 3.14).

Khi c mt ca phgia th RON ca xng tng chng tphgia ZSM-5 lm tngch soctan ca xng. C th, khi thm 5 %kl phgia th RON tng 2-3 n v.RON tng l do thnh phn aromat trong xng tng (aromat c RON cao hn ccHC khc)[15].

Vi nguyn liu giu aromat th RON ca xng cao hn. 5 %kl phgia, RON canguyn liu giu parafin khong 92 n vcn nguyn liu giu aromat th RON l

95 v 96n v. Ngay ckhi cha c phgia thm vo th RON ca nguyn liugiu aromat cng cao hn so vi nguyn liu giu parafin (92,5n vso vi 90v 91 n v).




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0% 1% 3% 5% 10% 20%

0

5

10

15

20

25

30

35

40

45

5055

60

65

Th

anhphanPIONAtrongxang(%k

l)


P

I

A

N

O

Hnh 3.16: nh hng ca nguyn liu v nng phgia n thnh phn PIONA

trong xng ca nguyn liu A1

0% 1% 3% 5% 10% 20%

0

2

4

6

8

10

12

14

16

18

Thanhphan

PIONAtrongnguyenlieu(%kl

)


P

I

A

N

O

Hnh 3.17: nh hng ca nguyn liu v nng phgia n thnh phn PIONA

ca nguyn liu A1 trn nguyn liu




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Nhn thy, thnh phn parafin, isoparafin, olefin v naphten (trong xng v ctrong nguyn liu) u gim khi tng nng ph gia (hnh 3.16 v hnh 3.17).iu ny chng tcc thnh phn ny b cracking khi c mt ca phgia, lng

mt i ny tuyn tnh vi nng ph gia thm vo. Trong khi , thnh phnaromat trong xng tng nhng trong nguyn

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