Đồ án kỹ sư 2

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Thit kphn xng reforming xc tc

Mai Ngc ChinKTHH5K54 1

ti: Thit kphn xng Refeforming xc tc nng xut 2,2 triu tn/ nm vi

s thit b xc tc cnh.

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Mc lc

PHN CNG NGH........................................................................................................ 18

II. Cng ngh Reforming ............................................................................................... 18II.1 Cc yu tnh hng n qu trnh .................................................................... 18

II.1.1. nh hng ca nhit ................................................................................ 19

II.1.2. nh hng ca p sut ................................................................................. 20

II.1.3. Tc np liu ............................................................................................. 21

II.1.4. T l hydro/hydrocacbon nguyn liu .......................................................... 21

II.2. Gii thiu mt ss cng ngh ..................................................................... 22

II.2.1. Gii thiu chung ........................................................................................... 22II.2.2 Mt ss dy chuyn cng ngh ............................................................. 28

II.2.2.1 S cng ngh qu trnh platforming ca hng UOP vi lp xc tc cnh ....................................................................................................................... 28

II.2.2.2 S cng ngh qu trnh magnaformig do hng Chevron, s dng xctc Pt - Re ............................................................................................................. 30

II.2.2.3 Dy chuyn reforming vi lp xc tc chuyn ng .............................. 32

II.2.2.4 Qu trnh New reforming ........................................................................ 36

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MU

Vo nhng nm 1859 ngnh cng nghip ch bin du mra i v t sn

lng du mkhai thc ngy cng c pht trin mnh v slng cng nh v cht

lng .

Ngy nay vi s pht trin v tin b ca khoa hc k thut, du m trthnh

nguyn liu quan trng trong cng ngh ho hc. Trn c snguyn liu du m, ngi

ta sn xut c hng nghn cc ho cht khc nhau, lm nguyn liu cho ng c,

nguyn liu cho cc ngnh cng nghip khc .

Ngnh cng nghip ch bin du nc ta ra i tuy cha lu, nhng n c

nh gi l mt ngnh cng nghip mi nhn, c bit l trong giai on t nc ta ang

bc vo giai on cng nghip ha - hin i ha. t c nhng mc tiu m s

nghip cng nghip ha - hin i ha ra th cn phi p ng mt nhu cu rt ln

v nguyn liu, nhin liu cho pht trin cng nghip v kinh t.

Trong cng nghip ch bin du m cc qu trnh chuyn ho ho hc di tc

dng ca cht xc tc chim mt t l rt ln v ng vai tr v cng quan trng. Cht

xc tc trong qu trnh chuyn ho c khnng lm gim nng lng hot ho ca phn

ng v vy tng tc phn ng ln rt nhiu. Mt khc khi c mt ca xc tc th c kh

nng tin hnh phn ng nhit thp hn. iu ny c tm quan trng i vi cc

phn ng nhit dng (phn ng hydro ho ankyl ho , polyme ho ) v nhit cao

v mt nhit ng khng thun li cho phn ng ny.

S c mt ca cht xc tc trong qu trnh chuyn ho ho hc va c tc dng

thc y nhanh qu trnh chuyn ho , va c khnng to ra nhng nng cn bng

cao nht, c ngha l tng hiu sut sn phm ca qu trnh. Trong qu trnh chuyn ho

ho hc di tc dng ca xc tc th qu trnh reforming xc tc chim mt v tr quan

trng trong cng nghip ch bin du m, lng du mc ch bin bng qu trnh

reforming chim t l ln hn so vi cc qu trnh khc. Qu trnh reforming xc tc

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c xem l mt qu trnh ch yu sn xut xng cho ng c, l mt qu trnh quan

trng khng th thiu trong cng nghip ch bin du.

C thni qu trnh reforming ra i l mt bc ngoc ln trong cng ngh ch

bin du. Trc y ngi ta dng xng chng ct trc tip c pha trn thm ph gia (ch) lm tng tr s octan. Ngy nay ngi ta s dng xng ca qu trnh reforming cho

ng c th cht lng m bo hn ,t nh hng n mi trng hn.

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PHN TNG QUAN

I. C SHA HC CA QU TRNH REFORMING XC TC

Reforming xc tc l mt qu trnh chuyn i cc thnh phn hydrocacbon canguyn liu m ch yu l naphten v parafin thnh hydrocacbon thm c tr s octan

cao, s dng nguyn liu l xng chng ct trc tip v gn y nh s pht trin ca cc

qu trnh lm sch bng hydro m ta c th s dng xng ca cc qu trnh lc du khc

(nh xng ca qu trnh cc ha, xng cracking nhit...). Qu trnh ny c tin hnh

trn xc tc hai chc nng thng cha platin (trong hn hp vi cc kim loi qu khc

v mt halogen) c mang trn cht mang xit nhm tinh khit.

Mc ch ca qu trnh l sn xut xng c tr s octan cao (RON trong khong t

95 - 102) m khng phi pha thm ch. ng thi, do sn phm ch yu ca qu trnh l

hydrocacbon thm nn qu trnh cn c ng dng sn xut BTX (khi nguyn liu

v phn on naphta nh c nhit si t 310 - 340oF) l nhng nguyn liu qu cho

tng hp ha du. Ngoi ra, qu trnh cn l ngun thu hydro nhiu nht v r nht.

I.1. Cc phn ng xy ra trong qu trnh Reforming xc tc

Bao gm cc phn ng: dehydro ha cc hydrocacbon naphten, dehydro vng hacc hydrocacbon parafin, ng phn ha, hydrocracking. Ngoi ra cn cc phn ng ph,

tuy khng lm nh nhiu n cn bng ca phn ng chnh nhng li nh hng ln n

hot ng v bn ca xc tc. l cc phn ng :

Phn ng phn hu v kh cc hp cht c cha oxy, nit , lu hunh thnh H2S,NH3 , H2O.

Phn ng phn hu cc hp cht cha kim loi v halogen.

Phn ng ngng t cc hp cht trung gian khng bn nh olefin, diolefin vi cchydrocacbon thm, dn n to thnh hp cht nha v cc bm trn b mt xc

tc .

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5000C

>5000C

+ 3 H2

+ 3 H2

CH3CH3

V th pht trin qu trnh reforming xc tc, ngi ta phi hn ch ti mc ti a

qu trnh to cc. Trong thc t sn xut ngi ta thng dng p sut v nng hydro

cao hoc tin hnh ti sinh lin tc xc tc (RCC)

I.1.1. Cc phn ng dehydro ho

- Dehydro ho cyclo alkal to hydro cacbon thm:

5000C th nng lng hot ho ca phn ng to benzen l 51,6 Kcal/mol, cn to

Cyclo hexan l 72,1 Kcal/mol. V vy 5000C ch xy ra phn ng to benzen.

y l nhng phn ng thu nhit v vy khi tng nhit v gim p sut th hiu

sut hydrocacbon thm tng ln. Ngoi ra khi hm lng hydrocacbon naphten tng ln

trong nguyn liu th qu trnh Reforming stng r rnghm lng hydrocacbon thm.

Phn ng tng tr s octan ca xng cn ph thuc hm lng n-parafin cha bin i

trong sn phm v chng c tr s octan kh thp (NO ca n-heptan bng 0). Do , ngoi

phn ng hydro ho naphten cn phi tin hnh phn ng khc sao cho t hiu qu

qu trnh Reforming.

- Dehydro ho parafin to olefin:

C9 H20 C 9H18 + H2

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n C7H16

+ 3 H2

CH3

+ 4 H2

CH3

n C7H14

- Dehydro ho vng ho parafin hoc olfin to cht thm:

Phn ng dehydro vng ho n-parafin xy ra kh khn hn so vi naphten.

Ch c nhit cao mi thu nhn c hiu sut hydro cacbon tng, hng s cn

bng to hydro cacbon thm cng tng ln .

Bng 1: nh hng ca nhit v chiu di mch cacbon ti hng s cn

bng ca phn ng dehydro vng parafin.

Phn ng 4000K 6000K 8500K

n - C6H14 C6H6 + 4H2 3,82.10-12 0,67 3,68.105

n - C7H16 C7H8 + 4H2 6,54.10-10 31,77 9,03.105

n - C8H18 C6H5 - C2H5 + 4H2 7,18.10-10 39,54 1,17.107

n - C9H20 C6H5C3H5 +4H2 1,42.10-9 65,02 1,81.107

Khi tng nhit hng s cn bng ca phn ng dehydro vng ho tng rt

nhanh, nhanh hn naphten. Nhng tc hydro ho li rt nhy so vi s thay i p

sut hoc t s H2/RH nguyn liu.

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450 500

P=18kg/cm2

4000

n-C720

60

80

100

40

H2/RH=4

H2/RH=10

445 500

nC6550

t0C

H2/RH=10

18kg/cm2

H2

/RH=4

20

40

60

80

100

Hnh 1 Hnh 2

Hnh 1: Cn bng n - C6benzen trong phn ng dehydro vng ho.

Hnh 2: Cn bng n - C7toluen trong phn ng dehydro vng ho.

Dehydro vng ho to hydro cacbon thm l mt trong nhng phn ng quan

trng nht ca Reforming xc tc v n bin i mt lng ln cc hp cht c tr soctan thp ca nguyn liu thnh cc hydrocacbon thm l cc cu t c tr s octan cao.

I.1.2. Cc phn ng izome ho

- Izome ho : n - parafin izo - parafin

V d: n - C7H14 metyl hexan.

- Hydro Izome ho:

V d: Heptan -1 + H2 2 metyl hexan

- Izome ho alkyl: xyclopetan xyclohexan

CH3

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-Izome ho alkyl thm

I.1.3. Cc phn ng hydro cracking parafin v naphten.

- i vi paraffin thng xy ra phn ng hydro cracking v hydrogemolyse:R-C-C-R1 R-CH3(izo) + R1 - CH3(izo) + Q=11Kcal/mol

R- C-C-R1 R2-CH3 + CH4 : phn ng hydrogenolyse

- i vi naphten:

+ H2 R3H R4H + R3H + Q = 20 Kcal/mol

Ngoi ra cng cn c cc phn ng hydrodealkyl ho cc hydrocacbon thm:

+ H2 C6H6 + RH + Q = 12 - 13 Kcal/mol

I .1.4. Ccphn ng tch nguyn t d th

- Hydro denit:

+ 5H2 C5H12 + NH3

C2H5CH3

CH3

R2

R1

+H2

R

R

N

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- Hydro desunfua:

+ 4H2 C5H12 + H2S

- Tch oxy:ROH +H2 RH +H2O

Ngoi ra cn c cc phn ng phn hu cc hp cht kim loi halogen.

I.1.5. Cc phnng to cc

y l cc phn ng khng mong mun xy ra trong qu trnh Reforming nhng

do stng tc ca olefin, diolefin v cc hp cht thm a vng m to thnh cc.Cc s kh to ra hn iu kin nhit thp, p sut cao v t l H2/RH cao.

Phn ng to cc l phn ng phc tp hn ch s to cc ngi ta phi s dng p

sut hydro va sao cho cc ch to ra khong 3-4% so vi trng lng ca cc xc tc

trong khong thi gian t6 thng n 1 nm nhng nu tng p sut th cn trto cc

hydrocacbon thm.iu ny i hi cc nh sn xut phi ch iu kin cc chc hoc

tnh ca xc tc gp phn iu khin c qu trnh to cc ca qu trnh reforming.

I.2. C ch phn ng Reforming xc tc

I.2.1.C ch phn ng reforming hydrocacbon parafin:

Nhiu nh nghin cu cho rng phn ng Reforming hydrocacbon parafin xy ra

theo 3 giai on:

- Dehydro ho parafin.- ng vng.- Dehydro ho hydro cacbon vng thnh hydro cacbon thm.

Giai on u v cui xy ra trn tm xc tc kim loi, cn giai on gia xy ra

trn tm axit. Cc giai on c th xy ra xen knhau. C ngha l trong khi giai on

ny cha kt thc th giai on khc bt u nhs tn ti tm xc tc axit bn cnh

SCH3

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R

- H2 - H2- H2

A + H+ A + H

+ A + H

+

- H2

+ + +

- H2 - H2 - H2

- H+ - H

+ - H

+

MM MM

nhng tm xc tc kim loi m cc giai on c th xy ra ni tip hoc gn nh ng

thi xy ra.

V dnh phn t n - heptan (n - C7H16) chuyn ho thnh Toluen nh sau:

Vi A l tm axit, M l tm kim loi

C chng vng ca cacbocation bc ba cho thy khi Reforming n -C6 th khng

phi vng 6 cnh u tin c to ra m chnh l hp cht vng nm cnh (metyl

cyclopetan) to ra u tin:

Tc giai on ng vng nh hn nhiu so vi giai on dehydro nn khi

Reforming naphten th dhn nhiu so vi parafin.

I.2.2. C ch phn ng Reforming hydro cacbon naphten.

Qu trnh chuyn ho cyclohexan thnh benzen.

- H2

- H2A

A

M H M

A

C1 - C5- H2 A + A + A

- H2

M

+H+

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I.3. Nhit ng hc ca phn ng v iu kin phn ng

Xt thng s nhit ng hc ca mt s phn ng quan trng trong qu trnh

reforming xc tc qua cc phn ng ca hydrocacbon C6.

Bng 2: Cc thng snh it ng hc cc phnng hydrocacbon C6

Phn ng Kp 500oC H Kcal/mol

Cyclohexan C6H6 + 3H2

Metyl cyclo pentan Cyclohexan

n - hexan C6H6 + 4H2

n - hexan Hexen - 1 + H2

n - hexan 2 - metyl pentan

6.105

0,086

0,78.105

1,1

0,037

52,8

- 3,8

63,8

- 1,4

31,0

Cc s liu nhit ng hc cho thy ti cn bng cyclo hexan chuyn ha thnh

aromatic p sut ca hydro v ch mt lng nh olefin tn ti vi parafin.

Nhng phn ng chnh ca reforming l thu nhit. Phn ng isome ho l trung

ha nhit trong khi phn ng hydro cracking to nhit , cc s liu cng cho thy hiu

ng nhit ca phn ng ph thuc chnh vo nng xyclonapatran trong nguyn liu v

n hp th nhit mnh nht, v nhit ca phn ng c ly t hn hp nguyn liu v

khi nn nhit ca hn hp ny gim.

Phn ng dehydro to vng ca parafin v phn ng dehydro ha ca naphtan l

nhng phn ng chnh lm tng tr s octan. Cn bng nhit ng ca nhng phn ng

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ny dch chuyn v pha sn phm phn ng khi p sut ring phn ca hydro thp v

nhit phn ng cao (500oC).Tuy nhin iu kin ny thch hp to thnh cc v s

to cc ch c thngn chn bng cch thc hin phn ng trong mi trng hydro, nu

p sut hydro cng cao, s lng ng cc trn b mt xc tc cng t. Vic tng p suthydro cng khng lm chm phn ng hydro ha to ra aromatic.

Vy qu trnh reforming xc tc phi c thc hin di p sut cao v hydro sn

phm c hon li vng phn ng .

Phn ng hydrocracking thch hp nhit v p sut ring phn ca hydro cao,

phn ng ny thng khng mong mun trong qu trnh reforming v chng tiu th

hydro v to ra hydrocacbon pha lng. (Hnh 8) minh ha s ph thuc ca hiu sut

phn ng vo p sut phn ng ti nhng tr s octan khc nhau.

Hnh 3: H iu sut phnng vp sut ti nhng trsoctan khc nhau.

Ti p sut cao cho trc, tr s octan c thc tng khi tng nhit mc d

iu ny gy ra s mt mt hiu sut do phn ng hydrocracking tng ln. Nh vy qu

trnh thng c thc hin p sut thp t c hiu sut pha lng tng ln. Tuy

nhin, p sut ring phn ca hydro phi cao trnh s to thnh nhng hp cht

khng no c khnng b polime ha to thnh cc.

Trong thc t, qu trnh c th c tin hnh trong khong nhit 455

510oC v p sut 6,5 50 atm. iu kin ch chuyn ha mt phn aromatic cn nu thc

6

7

8

9

10

0 1 2 3 4 5

p sut thit b

Hiusutphnng-

RON85

RON95RON102

RON104

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hin nhit cao hn v p sut khong 10 atm th c th chuyn ha gn nh hon

ton naphten thnh aromatic ti cn bng vi nhng qu trnh lm vic p sut cao t

34 50 atm th vn tc phn ng hydrocracking cao, mc chuyn ha thnh hp cht

thm gim (bng 5), vn tc phn ng kh hot tnh xc tc v hiu sut hydro thp.Ngc li, p sut thp (8,5 20,5 atm) chuyn ho cc hp cht thm cao, hiu

sut hydro cao, phn ng hydrocracking gim, nhng li nhanh chng kh hot tnh xc

tc do s to thnh cc.

Bng 3: c trng vn tc vhiung nhit ca nhng phnng reformingquan trng

Loi phn ng

Vn tc

tng i

nh hng ca stng p

sut tng cng

Hiu ng

nhit

Hydrocracking Thp nht Vn tc tng Ta nhit va phi

Dehydro ha tovng

ThpKhng nh hng ti sgim nh trong vn tc

Thu nhit

isome ha caparafin

Nhanh Gim vn tc Ta nhit t

isome hanaphten

Nhanh Gim vn tc Ta nhit t

Dehydro haparafin

Kh nhanh Gim chuyn ha Thu nhit

Dehydro hanaphten

Rt nhanh Gim chuyn ha Rt thu nhit

Nhit phn ng c chn lm cn bng gia stng hot tnh xc tc v

stng vn tc phn ng kh hot tnh khi nhit tng.

Khong nhit t 460 525oC v thng l gia 482 v 500oC. Nhng qu

trnh hot ng p sut thp v nhit kh cao to ra sn phm c tr s octan cao

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nht. Khi xc tc b mt hot tnh trong qu trnh hot ng nhit thng c gim t

t duy tr tr soctan khng i.

Khong vn tc th tch l t0,9 n 5 phn th tch nguyn liu lng trn th

tch xc tc trong mt gi, thng dng nht l t 1 2 . Nn la chn vn tc sao chonhng phn ng hydro cracking xy ra trong gii hn cho php v nhng phn ng

dehydro ha to vng xy ra t yu cu mong mun. Phn ng thm ha v isomeho

khng bnh hng bi vn tc khng gian nn nhng phn ng ny t cn bng ngay

c khi vn tc khng gian cao.

T l mol gia hydro v hydrocacbon nguyn liu thay i t3 n 10, nhng

ph bin nht l t5 n 8. T l ny th nh hng bt li n phn ng thm ha, tng

phn ng hydro cracking v lm gim vn tlc phn ng nh hot tnh xc tc. Gi tr

la chn thng gii hn thp phn ng hydro cracking xy ra t yu cu v s kh

hot tnh xc tc l thp. Nhng naphtan c nhnh thng l thnh phn chnh ca

nguyn liu. Nguyn liu c hm lng hydrocacbon khng no cao phi c hydro ha

trc khi phn ng gim tiu th hydro trong phn ng v s kh hot tnh xc tc.

Nng ca tp cht trong nguyn liu ng vai tr cht gy ngc xc tc phi c

iu khin nghim ngt. Sunfua lm ngc chc nng kim loi ca xc tc nn phiduy tr nng nhhn 1 ppm i vi nguyn liu cho xc tc mi. Nguyn liu c hm

lng sunfua cao phi c hydro sunfua ha trc phn ng. Cc hp cht nit hu c

b chuyn thnh amoniac lm ngc chc nng axit ca xc tc. Nng ca n phi

nhhn 2 ppm. Nit thng c loi ra khi nguyn liu xl hydro xc tc, ng thi

vi hydro desunfua ha. Nc v cc hp cht cha Clo cng l thnh phn khng mong

mun trong nguyn liu v n thay i axit ca cht mang v lm o ln cn bng

ca nhng phn ng ang xy ra v nhng hp cht ny loi b, hm lng ca chngcn phi iu khin cn thn duy tr axit ca xc tc. Nhng kim loi nh ASipb,

Cu phi gi nng rt thp v chng to hp kim vi ch lm kh hot tnh ca xc tc.

Hm lng asen trong nguyn liu phi thp hn 30 phn t.

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I.4. Xc tc Reforming

Xc tc s dng trong qu trnh Reforming l loi xc tc lng chc nng.

- Chc nng oxy ho - kh c tc dng lm tng tc ca phn ng hydroho - kh hydro.

- Chc nng axit: c tc dng thc y cc phn ng theo c ch ion cacbonnh ng phn ho v hydro cracking vng ho.

I .4.1 Vai tr ca xc tc hai chc nng

I .4.1.1 Platin

Platin l cu t rt tt, l kim loi c dng ch yu trong qu trnh reforming

xc tc. Palatin khng nhng xc tc cho phn ng dehydro ha cc naphten v phn ng

dehydro - vng ho cc parafin to ra hydro cacbon thm m platin cn c tc dng thc

y c phn ng no ha cc hp cht trung gian: olefin, diolefin... lm gim tc to

cc trn b mt cht xc tc l mt nguyn nhn chnh dn ti vic gim hot tnh cht

xc tc.

Hm lng platin trong cht xc tc reforming chim khong 0,3 0,7 (% khi

lng) . Hm lng pt c nh hng n hot tnh ca xc tc . v d khinguyn liu

cha hm lng parafin ln m dng xc tc cha 0,35 % trng lng pt trong xc tcth nhn c xng c tr s octan l 102 m khng cn pha thm nc ch .

phn tn ca pt trn cht mang AL2O3cng nh hng n hot tnh ca xc

tc . Trong qu trnh lm vic ca xc tc hm lng pt hu nh khng thay i nhng ta

vn thy hot tnh kh hydro li gim xung l do cc tinh th pt b thiu kt t li

thnh cc tinh th ln . V vy tm hot ng b gim xung .

Vy hot tnh ph thuc ch yu vo hm lng kim loi pt v c bit l

phan tn ca n trn cht mang Axt . ngi ta thy rng nu cc ht phn tn c kch

thc nhhn 10A0th l tm hot ng mnh , cn kch thc ht phn tn ln 70A0

th xc tc khng c hot tnh i vi cc phn ng chnh ca qu trnh reforming .

iu chnh tng quan gia hai xc tc th pt ch nn chim 1% b mt ca cht mang .

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Khi nghin cu ngi ta thy rng nu cho thm nguyn t Re vo c tc dng

km hm s thiu kt ca cc tinh th pt v nguyn t Re s kt hp vi pt to thnh hp

kim c n nh cao hn pt nguyn th. Do xc tc ca qu trnh reforming ngy

nay l AL2O3 c thm nguyn t Re c hot tnh cao hn , n nh v bn nhit caohn.

I .4.1.2 Cht mang

Cht mang trong xc tc reforming c th l Al2O3 hoc l SiO2, thng th ngi

ta hay dng Al2O3. l mt Oxit c b mt ring ln (250 m2/g), chu nhit cao.

Bn thn Al2O3 lmt axt lewis v nguyn t nhm cn c mt lng t t do, cn

Al2O3 cha nc l mt axit Bronsted v mang H+.

Cht mang AL2O3 cn phi tinh khit ( hm lng Fe , Na khng qu 0,02% trng lng)

tng cng tnh axit ngi ta thng halogenua ha ri ch ha nhit. y

thng dng clo.

Nu s dng cht mang - AL2O3 hay- AL2O3 vi din tch b mt khong 250

m2/g th c b sung thm cc hp cht halogen nh flo ,clo, hay hn hp ca chng .

Axt tng khi tng hm lng ca halogen , thc t cho thy ch nn khng ch hm

lng ca halogen khong 1% so vi xc tc trnh phn hu mnh . Halogen c

a vo xc tc khi ch to hoc khi ti sinh xc tc . Khi c clo th qu trnh xy ra nhsau :

Al - OH

O+ Cl-

+ OH-

Al - ClAl - OH

Al - OH

O

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Chc nng Axt c th hin bi cht mang . Axt ca n c vai tr c bit

quan trng khi ch bin nguyn liu parafin c trng lng phn t ln : cc tm Axt

kch ng phn ng hydrocracking ca cc parafin , phn ng ng phn hohydrocacbon naphten 5cnh thnh 6 cnh , tip theo l cc naphten 6 cnh b kh

hydro to thnh cc hydrocacbon thm .

I.4.2. Nhng yu cu i vi xc tc reforming:

Xc tc cn c hot tnh cao i vi phn ng to hydro cacbon thmc

hot tnh i vi phn ng ng phn ho parafin v c hot tnh thp i vi phn ng

hydro cracking.

- Xc tc phi c chn lc cao- Xc tc phi c bn nhit v khnng ti sinh tt.- Xc tc phi bn vi cc tc nhn gy ngc (cc hp cht ca lu hunh,

nit, xy, nc mui ca kim loi nng v cc tp cht khc).

- Xc tc phi c n nh cao (khnng bo ton hot tnh ban u trongsut thi gian lm vic).

- Xc tc c gi thnh r.

PHN CNG NGH

II. Cng ngh Reforming

II.1 Cc yu t nh hng n qu trnh

Qu trnh reforming c cc thng s cng nghchnh nh : nhit , tc np liu,p sut v t l mol gia H2/RH ca nguyn liu.

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II.1.1. nh hng ca nhit

Qu trnh reforming xc tc tin hnh trong iu kin nhit nm trong khong

4795250C, khi iu kin p sut v tc thtch khng i. Nu gim nhit th s

tng hiu xut xng, hiu sut kh gim, lng hydrocacbon thm khng nhiu nn tr s

octan ca xng khng cao, tuy nhin t to cc bm trn b mt xc tc nn thi gian lm

vic ca xc tc di hn. Ngc li khi tng nhit qu trnh th hm lng kh tng

ln, thnh phn lng gim xung dn n hiu sut xng gim , tuy nhin lng

hydrocacbon thm tng nn tr s octan ca xng tng . khi nhit tng th khnng to

cc cao nn d lm mt hot tnh ca xc tc .V vy, iu chnh nhit sao cho ph

hp vi cc thng s k thut khc m bo hiu sut , cht lng ca sn phm yu

cu .

Bng 4:nh hng ca nhit ti mt schtiu ca sn phm

Ch tiuNhit (oC)

435 450 465 480

Hiu sut xng kh propan (%) 98 96,8 95 91,6

Hm lng phn on c To

s n

100oC (% TT)34 36 41 46

Hm lng hydrocacbon thm

trong xng (% TT)19 27 35 45

p sut hi bo ha ca xng

(mmHg)

310 350 430 590

Tr octan theo phng php

nghin cu (khng pha nc ch)67,5 74 80,5 89

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I I.1.2. nh hng ca p sut

Phn ln cc phn ng chnh ca qu trnh reforming xc tc u km theo qu trnh

tng th tch .Theo quan im nhit ng hc th p sut cao s cn trqu trnh ca cc

phn ng tng thtch c ngha l cn trqu trnh to hydrocacbon thm. Nhng nu p

sut thp th phn ng cracking xy ra mnh, dn n to cc nhiu v vy ngi ta phi

duy tr p sut cao trong h thng. p sut trong h thng c quyt nh ch yu bi

hot tnh v chn lc ca cht xc tc. V dtrc s dng xc tc Mo/Al2O3 th p

sut trong h thng chn 15 20 at. Nhng hin nay thng dng xc tc Pt/Al2O3 th

duy tr p sut 20 40 at trong h thng m hot tnh to hydrocacbon thm vn m

bo.

p sut ca qu trnh l nhn t chnh nh hng n hiu sut v s quay vng xc

tc, p sut t 400 500 psi thch hp thi gian quay vng xc tc di, do vy s gim

p sut, cn bng phn ng dehydro ha chuyn v pha lm gim hiu sut sn phm

thm v hydro. S gim p sut lm gim khnng hydrocracking. Vic tng phn ng

dehydro ha v phn ng hydrocracking lm tng hiu sut C5 v sn phm reforming.

Nhng s gim p sut thp s kh hot tnh xy ra nhanh n mc thi gian rng ca

xc tc ch vi ngy, trong khi p sut cao thi gian sng ca xc tc c thn 1 nm.

Cc thit b bn ti sinh khng thun li cho hot ng p sut thp cho n khi sa

vo xc tc hai hay nhiu kim loi lm gim mc to cc. Nhvy c th s dng p

sut 200 250 psig m vn duy tr c thi gian quay vng xc tc kh khi hot ng

p sut cao. Vi thit b tun hon v thit b lp xc tc chuyn ng th p sut c th

gim n 85 psig. Trong nhng h thng nhiu thit b hoc thm ch trong cng mt

thit b gim p sut c ththay i theo sthay i t l cp liu v t l kh tun

hon.p sut ring phn ca hydro cng nh hng ng kn qu trnh, nh hng ny

c minh ho bng s ph thuc vn tc phn ng dehydro ha ng vng ca n -

heptan c xc tc bi Pt/Al2O3 vo p sut ring phn hydro.

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Khi khng c hydro th khng xy ra phn ng v b mt kim loi b che ph bi cc

khi tng p sut hydro, b mt kim loi c lm sch mt phn v c phn ng dehydro

ho ng vng u xy ra. Nu p sut ring phn ca hydro vt qu 10 atm th c th

loi b cc hu nh hon ton. Nhng nu tng hn na th hn ch vn tc phn ngdehydro ha, p sut ring phn cng nh hng n phn ng isomeho v

dehydroisome ha.

I I.1.3. Tc np liu

Khi tng lu lng nguyn liu (hay gim cht xc tc trong cc thit b phn ng ) s

lm gim thi gian tip xc ca cc cht tham gia phn ng vi cht xc tc dn n lm

tng hiu sut xng n nh v tng hm lng hydro trong kh tun hon , gim hiu sut

hydrocacbon thm dn n tr s octan gim . Ngha l khi tng tc th tch th ccphn ng kh hydro ca napten , hydro cracking, ng phn ho butan v pentan s

chim u th v xy ra nhanh hn. Cn cc phn ng i hi thi gian nh kh hydro ,

vng ho parafin, kh alkyl ,hydrocracking , hydrocacbon nh xy ra yu hn . v vy

tnh ton tc np liu ring sao cho ph hp .Trong qu trnh reforming xc tc th tc

np liu ring thng c duy tr trong khong 1,5 gi(h-1)

I I.1.4. T l hydro/hydrocacbon nguyn liu

T l mol hydro trong kh tun hon trn mol nguyn liu trong qu trnh reforming

xc tc thay i trong mt gii hn rt rng tu theo mc ch ca qu trnh. p sut

hydro l yu t rt quan trng trnh s to cc . T l mol H2/RH xc nh nng

ca hydrocacbon trong vng phn ng .t l mol hydro s dng n nh do np kh cha

hydro cho tun hon trli t qu trnh phn ng.

Chn t s tun hon kh cha hydro c quyt nh bi cc yu t : thnh phn

phn on ca nguyn liu, khc khe ca qu trnh v tr s octan ca sn phm xng.T l hydro trn nguyn liu cng cao th tc to cc trn xc tc cng nh v thi

gian lm vic ca xc tc cng ko di . song nu tng t l s dn ti tiu tn mt lng

nhit ng k, ng thi lm tng trlc thung v th tch ca thit b , ng dn.V

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vy cn phi iu chnh t l hydro trn nguyn liu sao cho ph hp vi yu cu sn

phm

II.2. Gii thiu mt s s cng ngh

I I.2.1. Gii thiu chung

Qu trnh reforming xc tc vi lp xc tc cnh u tin c p dng trong cng

nghip vo nm 1940 v khi dng xc tc molipden. Song qu trnh ny khng

c pht trin v s to cc qu nhanh trn xc tc.

Vo nm 1949, reforming xc tc s dng xc tc trn c sPt ra i v qu trnh ny lin

tc c ci tin,ci tin theo hng xc tc v ci tin theo hng cng nghv mang li

nhng kt qung k (bng 5) cho ta thy s ci tin v xc tc v cng ngh.

Bng 5: S lc tin hnh ci tin xc tc vcng ngh reforming xc tc trn th

gii .

1940 Reforming xc tc u tin s dng xc tc molipden

1949 Pht trin xc tc Pt

1950-1960 Rt nhiu qu trnh Reforming xc tc c pht trin t xc tc Pt

1960 Pht trin xc tc a kim loi (ngoi Pt cn c cc kim loi khc).

1970 Qu trnh reforming ti sinh xc tc lin tc ra i.

1980 Qu trnh reforming ti sinh xc tc sn sut hydrocacbon thm.

1990 Ra i qu trnh reforming xc tc mi (new reforming).

Tnm 1950, nhiu qu trnh reforming xc tc s dng xc tc Pt c pht trin

v qu trnh reforming trong khu lc du l cha kho chnh sn sut xng c tr s

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octan cao cng vi qu trnh cracking vi lp xc tc si (FCC). Qu trnh reforming xc

tc khi s dng thit b vi lp xc tc cnh nn n phi nh k dng lm vic ti

sinh xc tc b cc ha. Mt s qu trnh s dng l phn ng c ng van song song

d ti sinh xc tc tng l phn ng ring m khng cn phi dng lm vic ton b hthng (qu trnh powerformer).

Vo thp nin 1960, xc tc hai v a kim loi c pht trin. Xc tc hai v a

kim loi c ci tin c bn cao, chng li s to cc, gp phn nng cao cht

lng ca sn phm. Sn phm c RON = 100 m vn u t, chi ph vn hnh khng

cao .

u nhng nm 1970 mt ci tin ni bt vqu trnh reforming xc tc ra i l

qu trnh c ti sinh lin tc xc tc ca UOP v tip theo l ca IFP, xc tc b cc ha

c tho ra lin tc khi l phn ng v c a quay tr li l phn ng sau khi

c ti sinh trong thit bti sinh ring. Qu trnh ny c gi l qu trnh ti sinh lin

tc xc tc (CCR). Nhkhnng ti sinh lin tc xc tc b cc ha, qu trnh CCR cho

php dng p sut thp v tho lin tc, hng nm cha phi thay xc tc mi, cng nh

gim p sut m hiu sut hydrocacbon thm v H2tng ln ng k.

Ngy nay, qu trnh CCR vi p sut siu thp v c th lm vic p sut 3,5 at.Hu nh tt c cc qu trnh reforming xc tc mi c xy dng u l qu trnh CCR.

Bng 6. Cc hng i u tr ong qu trnh ci tin reformi ng xc tc

Tn qu trnhHng thitk

Loi thit b

phn ngLoi xc tc

Loi l tisinh

(Platformer)

PlatreformingUOP Xc tc cnh

R11 - R12

Pt = 0,375

Ti sinh

gin on

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0,75

Powerforming

(Powerformer)

EXXON

Xc tc cnhKX, RO,BO(Pt, Re)

Ti sinh

gin on

IFP reforming(IFP reforming)

IFP Xc tc cnh RG 400Pt (0,2 -0,6)

Ti sinhgin on

Maonaforming

(Maonaformier)

Engelhard

Xc tc cnhRD.150(pt =0,6);E500

Ti sinh

gin on

ReNiforming

(Reniformier)CRC Xc tc cnh FC (pt, Re)

Ti sinh

gin on

CCR plat-forming(CCR platFormer)

UOPXc tc chuynng, thit b phnng chng ln nhau

R16 : 20

pt, Re

Ti sinhlin tc

AromiZer IFPXc tc chuynng, thit b phnng chng ln nhau

Pt, ReTi sinh

lin tc

Phng php ti sinh xc tc ca qu trnh reforming xc tc thng c chialm 3 loi : Thit b bn ti sinh (xc tc cnh), thit b ti sinh tun hon (c

lp t 1 thit b phn ng ph) v thit b lp xc tc chuyn ng.

y vn c bn trong thit k thit b xc tc l cn bng nhit. Nhng phn ng

to ra nhng sn phm thm l thu nhit. Mc d nhng phn ng ny c b li bi

phn ng ta nhit hydrocracking, vn cn phi cung cp mt lng ln nhit vo vng

phn ng. Trong thit b lp xc tc cnh, nhit c cung cp bi vic s dng mt

s thit b ni tip vi s gia nhit li gia nhng phn ng. V nhng hp cht c kh

nng phn ng cao, phn ng u tin nn gim nhit ln xy ra thit bu tin.

Mi thit b tip theo c gim nhit thp hn thit btrc.

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Trong qu trnh xc tc chuyn ng nhit c cung cp bi dng kh tun hon.

Trong hydroforming pha lng, dng kh tun hon c a vo y ca thit bv i

qua lp xc tc tng si : Do s trn nhanh chng ca xc tc, nhit ca lp xc tc l

hng s. Trong xc tc chuyn ng khng c s trn ca xc tc, do dng kh tunhon nng c a vo vi im trong lp xc tc. Xc tc c t nng khi n i qua

mi im. Gia cc im nhit ca xc tc gim do tc dng ca nhng phn ng thu

nhit.

H thng bn ti sinh : Nguyn liu c s l trc khi i qua b phn trao i

nhit vi dng sn phm, nguyn liu kt hp vi dng kh tun hon i vo thit b cp

nhit tng nhit ln khong 900 980oF. Sau , nguyn liu i qua mt lot thit

b phn ng. Cc l nung gia cc thit b b li s mt mt nhit do cc phn ng

thu nhit. Sn phm sau khi trao i nhit vi nguyn liu c i vo mt my sy chn

khng. Ti y, sn phm lng c ly ra y cn phn nh c phn chia thnh

sn phm hydro v kh tun hon. Sn phm lng c a i n nh loi b phn

nh. Thit b ny ngng lm vic theo chu k ti sinh xc tc. Thi gian gia hai ln

ti sinh t nht l 6 thng. p sut trong thit bthng l t 500 550 psig (p sut cao).

Vi thit b ny, tr s octan ln nht ca sn phm cht khong RON = 100.vi cng

ngh ny mt d tin hnh p sut cao nhng trong cng nghip ch bin du qu trnh

ny vn cn kh ph bin , v quy trnh cng nghkh n gin ,u t ban u va phi

iu kin vn hnh khng qu kht khe.

H thng tun hon: H thng ny khc h thng bn ti sinh ch n c thm mt

s thit b phn ng d tr v mt h thng ng ng na xc tc trong mt thit b

c th ti sinh trong khi cc thit b kia vn lm vic. Thit b ny c th thay th cho bt

k thit b no trong h thng. u im ca qu trnh ny l p sut thit b thp nn ctht c hiu sut sn phm v tr s octancao (RON trn 100). Cc thit b cui

cng thng nhiu hn cc thit b trc v nhit trung bnh cao hn do vy n

thng c thay th thng xuyn hn. Do h thng ny lm vic p sut thp hn

(200 400 psig) v iu kin khc nghit hn thit b phn ti sinh nn vic ti sinh tng

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thit b thng xuyn ha v do hiu sut sn phm cao hn trong h thng bn ti

sinh.

H thng lp xc tc chuyn ng: Trong h thng ny, thit b thng c t

chng ln nhau t thit b cui cng . Nguyn liu cng c nung nng bng trao inhit. Thit b phn ng l loi thit b chy xuyn tm xc tc chuyn ng chm ti

thit bu tin nh n thit by. Xc tc b cc lng ng c a ti b

phn ti sinh khi phc li hot tnh ri np trli thit b phn ng th nht to

thnh mt chu trnh kn .

Vi cng ngh ny , nhti sinh xc tc lin tc m khng phi dng qu trnh ti

sinh xc tc nh cc dy chuyn c , v do vy xc tc va mi c ti sinh c

chuyn lin tc vo thit b phn ng . iu lm cho xc tc c hot tnh cao v n

nh hn ,v p sut thp thun li cho qu trnh .

Mt loi khc t ph bin hn l cc thit b phn ng c ring nh bn ti sinh. Xc

tc b lng cc c lng ra thit b cui cng v a i ti sinh. Xc tc mi v xc

tc ti sinh c a vo nh ca thit bu tin duy tr lng xc tc khng i.

V h thng ny hn ch s to cc trn xc tc nn n c th lm vic p sut thp

100 psig hoc iu kin khc nghit hn. S mt mt hiu sut sn phm c th hn ch

ti a nu chn c t l tun hon xc tc thch hp.

H thng xc tc tng si : H thng ny gm nhng thit b phn ng v thit b ti

sinh t ni tip nhau. H thng lm vic p sut 200 300 psig nhit 900oF.

duy tr nhit ny kh tun hon phi c un nng n nhit 1200oF (nhit

nguyn liu nhhn 1100oF gim cracking nhit). Nhng ng ng xon lm ngui

c lp trong thit bti sinh lm gim s qu nhit do t chy v gin nhit 1100oF xc tc c thc tun hon vi t l 1 pound/pound nguyn liu.

Nu t l tun hon cao hn, nhit t chy s c th truyn sang thit b phn ng v

ng ng lm sch c th loi b. Tuy nhin, nu tng t l tun hon yu cu nn kh

trong thit b ti sinh stng v modipden trong xc tc tun hon s b kh trong thit b

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phn ng v b oxy ha li trong thit b ti sinh. Mt phng php c s dng

truyn tt c nhit ti sinh m khng lm tng lng khng kh. Theo phng php ny,

mt vt liu trcha tinh chc tun hon gia thit b phn ng v thit b ti sinh

vi t l ph thuc vo t l tun hon xc tc.Cc h thng kt hp: tr c octan ca mt qu trnh reforming c thc nng cao

bng cch s dng nhng phng php chit, hp th hoc cracking nhit ph tr. S kt

hp gia qu trnh platforming v chit gi l reforming, trong khi s kt hp gia hp

th hoc reforming nhit vi Uareforming gi l iso - plus.

C rt nhiu qu trnh feforming khc nhau do cc cng ty khc nhau a ra. iu

kin hot ng ca mt squ trnh c a ra trong bng 6

Bng 7: iu kin hot ng ca mt squ trnh reforming

Xc tc Hydroforming Platforming

Xc tc Pt

Ti sinh

gin on

Ti sinh

tun hon

Thnh phn xc tctrn cht mang

Al2O3

10% MnO3 Pt thadogen 0,5% Pt Pt

Phn ng 875 - 950 850 950

T, oF 890 - 940 850 - 960 200 - 600 200 - 400

P, psig 100 - 300 200 - 700 1 - 5 1- 5

WHSP

pound/pound0,3 - 1 1- 4

Ti sinhLoi Ring Khng Gin on Tun hon

T, oF 1100 1050

P, Psig 200 250 300

Thi gian gia 2 Lin tc Vi nm 25 7,5 bbT

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ln ti sinh thng (1b)

II.2.2Mt s s dy chuyn cng ngh

II.2.2.1 S cng ngh qu trnh pl atformi ng ca hng UOP vi lp xc tc cnh

Trong cng ngh ch bin du , qu trnh reforming vi lp xc tc cnh vn cn

ph bin. y iu kin tin hnh qu trnh c chn m bo thi gian gia cc

ln ti sinh ln (thng trn 6 thng n mt nm). Qu trnh ti sinh xc tc c tin

hnh ng thi trong tc c thit b phn ng i vi h thng khng c cc thit b d

tr. H thng trong qu trnh reforming xc tc thc hin phn ti sinh xc tc c

tin hnh nh k ngay trong thit b phn ng. Loi h thng ny c th chia lm hai

nhm :

Nhm 1: Cc h thng trong qu trnh ti sinh xc tc c tin hnh ng thi trong

tc c cc thit b phn ng. H thng ny c tin hnh ch cng va phi. Chu k

lm vic ca xc tc ko di trong nhiu thng (c th 4-8 thng ). Thuc nhm ny c

th kn cng ngh ca cc nc Lin X (c) v M nh qu trnh Katforming v

Gudri-forming .

Nhm 2: Cc h thng trong qu trnh ti sinh xc tc c thc hin trong mt s

thit b d tr. N cho php khng cn dng ton b h thng reforming ti sinh xc

tc, tuy nhin h thng li phc tp hn v mt cng ngh. H thng nay tin hnh ch

cng v chu k lm vic ca xc tc ngn. Tiu biu cho nhm nay l cng ngh

Ultraforming v Platforming.

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Hnh 4: Cng ngh reforming vi lp xc tc cnh UOP platforming

Nguyn tc hot ng:

Nguyn liu l phn on naphta c sy kh v lm sch t b phn hydro

ho lm sch c trn vi kh hydro t my nn sau khi qua cc thit btrao i nhit v

c np ni tip vo l t nng v cc thit b phn ng t1 n 3 (ngy nay thng

dng n 4 l ). Sn phm ra khi l sau khi qua cc thit btrao i nhit c np tip

Kh

nh

Ngng t

hi lu

Thit b

phn ng

L gia

nhit

Nguyn liu

Thit b phn ng

Sn phm

reformat

My bm

Hydro

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vo thit bt nng v thit b lm sch. Sau qua thit b ngng t, sn phm s gi

nhit 38 0C. Kh khng ngng sc tch ra thit b tch kh. Phn ln kh ny

c my nn v tip tc tun hon li.

Phn cn li c dn sang b phn tch kh v s dng hydro sau khi tch cho cc

qu trnh khc , v d cho hydro ho lm sch.

Sn phm y ca thit btch c a qua thit btrao i nhit vi sn phm nng

ca y ct .Sn phm nh ca ct c dn sang thit bngng t. hi sc tch ra

khi dy chuyn . Sn phm lng c hi lu bng bm xng reforming n nh y

c a qua thit btrao i nhit ri qua thit b lm sch, sau qua b cha.

II.2.2.2S cng ngh qu trnh magnaformig do hng Chevron, s dng xctc Pt - Re

y l qu trnh ci tin cng ngh reforming truyn thng c hiu qu nht. Qu

trnh ny lm gim lng kh tun hon vo thit breforming u tin v tng lng

kh tun hon vo thit b cui cng

L phn ng

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Hnh 5: S cng ngh xc tc cnh Magnaforming

Trong thit bu tin, do nhng phn ng ta nhit nn phn ng dehydro ho

gim so vi phn ng hydrocracking. V vy, s gim lng kh tun hon vo thit b

ny lm gim nh hng sn phm kh do hydrocracking to ra. Magnaforming cng s

dng 4 thit b phn ng thay v 3 thit b, nhit u vo mi thit btng t thit b

u tin n thit b cui cng. T l mol kh tun hon/nguyn liu l 2,5 3 thit b

u tin v 9 10 thit b cui cng. Hiu sut sn phm lng tng t nht 1 2% nh-

ng gi tru t cng tng 6,5% so vi h thng 3 thit b.

Ti sinh xc tc: i vi h thng cng ngh ti sinh ng thi th cc bc tin

hnh nh sau :

L gia nhit

Trao i nhit

Lm lnh

Thit b tch

Hi

lng

Nguyn liu

Bm

My nn

Hi

Thp

n

nh

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u tin ngng bm nguyn liu, cho thit b phn ng ngng hot ng xong vn

tip tc bm kh ui ht cc hydrocacbon ng thi gim dn nguyn liu t l sau

ngng hn. Nhit h xung 2000c th ngng bm kh hydro, thi ht kh hydro

bng cch ht chn khng . Thi v thi kh tr sau bm kh tr n p sut khong 10atm, un nng thit b phn ng t t, khi nhit vo khong 2500c th bm khng kh

vo sao cho lng oxy vo khong 0,5% thtch v tng t tcho n 2% th tch th kt

thc. Khi cc chy ht, nhit vo khong 4000c , gi nhit trong l khng qu

5000c sau lm lnh, thi kh tr qua v cui cng thi kh hydro qua. Bt u khi

ng li h thng lm vic. Khi s cng ngh c s dng l d tr th vic ti sinh

khng lm gin on thi gian lm vic v chn gin l chuyn ng dn nguyn liu

sang l phn ng lm vic thay th, qu trnh ti sinh i vi l phn ng lm vic t-ng tnh trnh by trn .

I I .2.2.3 Dy chuyn reforming vi lp xc tc chuyn ngNm 1970 , mt ci tin ni bc vqu trnh reforming xc tc ra i l qu trnh

c ti sinh lin tc xc tc ca UOP v IFP gi l qu trnh CCR . n nm 1996 , hng

UOP xy dng c 139 nh my CCR cn IFP c 48 nh my CCR .

c bit ca dy chuyn ny l cc l phn ng chng ln nhau thnh mt khi. Xc

tc chuyn ng t chy t thit b phn ng trn cng xung thit b phn ng cui

cng, sau xc tc lm vic c chuyn sang thit bti sinh khi phc li hot

tnh ri np trli thit b phn th nht, to thnh chu trnh ln.

Trong cc h thng ny qu trnh ti sinh xc tc c thc hin trong mt thit b ti

sinh ring . y l h thng reforming xc tc hin i nht xut hin M nm1971.

Trong cc h thng ny, cc thit b phn ng c b tr chng ln nhau lm thnh mt

c cu chung nht. Xc tc i t thit b phn ng th 1 xung thit b phn ng th 2,

ri ln lt xung thit b th 3,4 v cui cng xc tc c a sang thit b ti sinh.

Sau khi xc tc ti sinh n li c a v thit b phn ng th nht. Nh vy qu

trnh reforming xc tc c thc hin lin tc. Nhly ra lin tc mt phn xc tc

ti sinh nn c th duy tr mc hot tnh trung bnh ca cht xc tc cao hn v n

nh hn so vi lp xc tc cnh. Do vy m p sut v bi s tun hon kh cha

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hydro c th gim xung tng ng 3,5-12 at v 400-500 m3/m3. Vic gim p sut c

nh hng tt n qu trnh, tng c hiu sut, tng nng hydro trong kh cha

hydro.

Ngy nay loi reforming ti sinh xc tc lin tc tr thnh rt ph bin. Nh tisinh xc tc lin tc m khng phi dng qu trnh ti sinh xc tc nh dy chuyn c

(dy chuyn reforming xc tc cnh). iu lm cho xc tc c hot tnh cao hn v

n nh hn, lm vic iu kin kht khe hn v vn cho hiu qucao hn.

Sau y s cp mt cch chi tit qu trnh reforming xc tc chuyn ng ca hng

UOP.

54

3

Nguyn

liu Sn phm

reformat

Hydro tun

hon

Kh

nhinliu

Xc tc ti sinhThu hi phn

nhkh

Phn

lng

1

2

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Hnh 6:S cng ngh qu trnh platforming ca hng UOP

1-thit b phn ng 2-l gia nhit

3-thp tch 4-thp n nh

5-thit b ngng t

Nguyn tc hot ng :

S reforming ti sinh xc tc lin tc ca hng UOP c trnh by (hnh 6). cim ring bit ca s l cc thit b phn ng chng ln nhau thnh mt khi. Xc tc

chuyn ng t thit b phn ng trn cng xung thit b phn ng cui cng. Xc tc

lm vic c chuyn sang thit bti sinh khi phc li hot tnh ri c np trli

thit b phn ng u to thnh mt chu trnh kn. Nhly ra lin tc mt phn xc tc

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ti sinh nn n c th duy tr mc hot tnh trung bnh ca cht xc tc cao hn so vi

h thng vi lp xc tc cnh. Do vy m p sut v bi s tun hon kh cha hydro

c th gim xung tng ng c th 9 12 at v 400 500 m3/m3. Vic gim c p

sut c nh hng tt n cht lng ca qu trnh, tng hiu sut, tng nng hydrotrong kh cha hydro.

Lng xc tc cha trong thit b phn ng rt khc nhau , thit b th nht ch cha

10-20% lng xc tc v cc thit b cui cha khong 50% khi lng xc tc .

B phn ti sinh xc tc :Xc tc lm vic chy t thit b phn ng cui cng xung b phn thu xc tc

bunke cha, sau chy xung ng nng. Ngi ta dng kh cha hydro tun hon tmy nn tun hon y xc tc v vn chuyn n ln nh vo b phn tch bi pha

trn l ti sinh. b phn ny ngi ta b sung kh hydro tun hon tch cc ht bi

mn ca xc tc v mang chng ra ngoi vi kh i vo ng tp trung bi cn xc tc ri

vo y b phn tch bi ri chy xung l ti sinh .

Ti sinh xc tc gm c 4 bc, 3 bc u l :t chy,t chy cc clo ho v lm

kh. Ba bc u xy ra vng ti sinh, v bc th 4 l kh xc tc xy ra trong b

phn kh ring.

t chy cc bm trn xc tc c tin hnh trong vng chy nm nh l ti sinh.

Xc tc a vo v chy xung gia mng chn hnh trng thng, khng kh nng

c thi theo hng bn knh i t ngoi vo trong qua lp xc tc sau lm lnh v

tun hon qua cc ng trong vng chy, xc tc vn chuyn ng xung dn v b phn

lm lnh ti sinh s ly nhit khi t cc. Vic t cc tun theo chc bit nghim

ngt m bo ht cc v khng nh hng xu n xc tc. Sau khi t chy cc thxc tc c cho qua vng clo ho clo ho v sau l sy.

Cui cng xc tc c cho vo vng kh tch bit vi 3 khu vc t clo ho sy trn ,

sau khi khxc tc c a theo ng dn xc tc vo ng xut xng, nu xt bin i

nguyn liu th kinh t nht vn l dy chuyn CCR.

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I I .2.2.4 Qu trnh New reforming

Sau mt thi gian di pht trin, cng nghip lc ha du thit lp c cng ngh

mi c khnng reforming chn lc kh ho lng v naphta nh thnh cc cu t c tr s

octan cao, cho php pha trn xng c cht lng cao v cc sn phm hydrocacbon thm.Tnm 1996 n nay, cng nghip du kh thay i cng ngh s dng naphta

nh v kh ha lng lm nguyn liu cho sn sut xng cao tr s octan v hydrocacbon

thm.

Trong nm 1997, qu trnh Newreforming c pht trin nhm mc ch ny. Cc b-

c phn ng ca qu trnh c th tng qut ha nh hnh 7.

NGUYN LIU HP CHT TRUNG GIAN SN PHM

Parafin nh

Olefin Oligome Hydrocacbon vng Hydrocacbon thm

Hydrocracking Sn phm cracking: metan, etan.

Hnh 7. S Phn ng Reforming parafin nh

Cc phn ng xy ra trong qu trnh "New Reforming" gm:

Dehydro ha olefin to ra olefin. Oligome ha olefin to thnh dime v trime. Vng ha dime v trime. Dehydro ha hp cht vng to thnh hydrocacbon thm.

Vng haDehydro ha

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Ngoi cc phn ng chnh trn, cn xy ra cc phn ng phnh hydro cracking to metan,

etan trong phn ng ngng t to cc bm trn xc tc.

Trong s cng ngh reforming mi ca UOP, xc tc c s dng trong qu trnh

l Zeolit c tnh chn lc hnh hc cho qu trnh vng ha. Tnh chn lc hnh hc caZeolit lm hn chkch thc phn t ca cc hp cht sn phm trung gian v cho sn

phm ch yu l hydrocacbon thm mt vng. So vi cc phn ng reforming bnh th-

ng khc, qu trnh "New Reforming" to cc bm trn xc tc nhiu hn.

Do vy vic ti sinh xc tc phi p dng cng ngh vi xc tc chuyn ng hay s

dng l d tr.

S pht trin ca "New Reforming" c khi qut bng 8:

Bng8: Cc qu trnh New Reforming trn thgii

Qu trnh Hng thit k Nguyn liu

Cyclar

Z - Former

Aromax

Aroforming

2forming

BP/UOP

MitSubishi/Chiyod

a

CRC

IFP

Mobil

LPG

LPG, Naphta nh

Naphta nh

Naphta nh

Naphta nh, naphta

nhiu olefin

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PHN TNH TON

I.Cc s liu u :

Cng sut : 2.2 triu tn/nm.

Nhit : 743 8030K.

Tc th tch LHSV: 2 h-1. ?

p sut : 40-45 at

Thi gian lm vic xc tc 1 nm

Lng cc bm trn xc tc (% trng lng) : 3 5%

T l H2/RH, (m3/m3) = 1500

Thit b phn ng chnh: l xuyn tm

Nguyn liu c nhng c tnh sau :Bng (17) c tnh ca nguyn liu :

T trng

(g/cm3)

Thnh phn phn on, K %, khi lng

0,733

Ts u Ts 50 Ts cui P N A

358 395 438 62,61 26 11,39

Đồ án kỹ sư 2

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