B CNG THNG

TRNG I HC CNG NGHIP TP.HCM

KHOA CNG NGH HA
*****

BI TIU LUN
MN: CNG NGH LC DU

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

MC LC
I)

CRAKING NHIT..............................................................................................1
1)

TNG QUAN...................................................................................................1

2)

C S L THUYT........................................................................................1
a)

S bin i paraffin......................................................................................1

b)

Bin i ca olefin.......................................................................................1

c)

Bin i ca naphten....................................................................................1

d)

Bin i ca hydrocacbon thm...................................................................1

e)

S bin i ca hp cht lu hunh.............................................................1

3)

QU TRNH CRAKING NHIT.....................................................................1

a)

Nguyn liu..................................................................................................1

b)

Sn phm ca qu trnh cracking nhit.........................................................1

4)

CC YU T NH HNG V S CNG NGH...............................1

a)

Cc yu t nh hng...................................................................................1

b)

S cng ngh v hot ng ca qa trnh cracking nhit.........................1

II) CC HA (COKING)........................................................................................1
1)

GII THIU QU TRNH CC HA............................................................1

a)

Mc ch......................................................................................................1

b)

Khi nim.....................................................................................................1

2)

PHN LOI.....................................................................................................1
a)

Cc ho gin on........................................................................................1

b)

Cc ha chm...............................................................................................1

c)

Qa trnh cc ha tip xc............................................................................1

d)

Cc ha tng si...........................................................................................1

3)

CC YU T NH HNG..........................................................................1
a)

Nhit :.......................................................................................................1

b)

p sut.........................................................................................................1

III) CRACKING HI (PYROLY)............................................................................1

1)

MC CH QU TRNH................................................................................1

2)

C IM QU TRNH................................................................................1

3)

LNG HI NC........................................................................................1
2

4)

NGUYN LIU................................................................................................1

5)

C CH TO THNH SN PHM CHNH..................................................1

6)

C CH TO THNH SN PHM PH......................................................1

7) S HNH THNH CC HYDROCARBURE ACETYLENIQUE V

ALLENIQUE............................................................................................................1
8)

S HNH THNH HYDROCARBURE AROMATIQUE...............................1

9)

S HNH THNH CC HYDRUACARBURE NNG..................................1

10)

SN PHM (VI NGHIM NGT = 0.52 )...........................................1

11)

TIU TH NNG LNG...........................................................................1

IV) VIS-BREAKING.................................................................................................1
1)

TNG QUAN...................................................................................................1

2)

NGUYN LIU................................................................................................1

3)

SN PHM......................................................................................................1

4)

CNG NGH VISBREAKING........................................................................1

5)

CC YU T NH HNG..........................................................................1

6)

a)

Nguyn liu..................................................................................................1

b)

Nhit ........................................................................................................1
CC S CNG NGH IN HNH........................................................1

CC QU TRNH CH BIN NHIT TRONG

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

Nguyn
liu

Sn phm chn

Nhit ,
o

p sut,

kg/cm3

Cracking hi

Etan

Axetylen

1000 1400

0,2 0,5

Cracking hi

Etan
Propanbutan

Etylen

800 850

0,2 2

Etylen propa

770 800

0,2 2

720 770

0,5 2

720 -750

0,5 2

Cracking hi

n
Cracking hi

Xng nh

Etylen
propylen

Cracking hi

Gasoil nh

Etylen
propylen

Cracking nhit

Gasoil nh

Xng

469 510

20 70

Cc ho

Cn nng

Cc

480 530

1 10

Vibreking

Cn nng

Gim tc nht

440 - 480

20 70

Cracking nhit l qu trnh phn hy di tc dng ca nhit, thc hin iu

kin nhit khong 470 n 540oC, p sut 20 n 70 at.

Nguyn liu s dng t phn gasoil n cn nng ca du, ph bin hay s

dng l cn mazut. Sn phm thu c bao gm kh cha nhiu olefin v xng.
Ty theo mc ch thu sn phm, nguyn liu s dng v ch cng ngh m
qu trnh c th chia cc qu trinh chuyn ha ha hc di tc dng ca nhit nh
sau:

Qu trnh cracking nhit

Qu trnh nhit phn (pyrly)

Qu trnh cc ha

Qu trnh visbreaking
y l cc qu trnh bin i nguyn liu du m di tc dng ca nhit

cao thnh cc sn phm rn, lng, kh. Thnh phn v s lng cng nh cht
lng ca sn phm cui c quyt nh bi cc thng s cng ngheejcuar qu trnh
nh:nhit , p sut, thi gian phn ng.
Trong qu trnh ch bin nhit kh cu trc c hai vn quan trng cn gii
quyt:

Ngn nga s to thnh cc trong ng phn ng hay trong cc thit b trao i

nhit.

m bo hiu qu s dng cao cc thit b trong dy truyn.

Nh vy trong nhng qu trnh chuyn ha ha hc di tc dng ca nhit

trn th qu trnh cracking nhit chim mt v tr tng i quan trng trong cng
ngh lc du.

2) C S L THUYT
Bn cht ca cracking l s b gy mch cacbon, thu c nhng phn t
mch cabon ngn hn ph hp vi yu cu .
L phn ng thu nhit,nn i hi iu kin nhit thch hp.
L qu trnh phc tp v nguyn liu gm s lng ln cc cu t ring bit,
di nhit cao dn n s bin i rt phc tp nn kh theo di
5

a) S bin i paraffin
CnH2n+2

CmH2m + CpH2p+2

Khi n 4 th lin kt C C bn hn C H

xy ra hin tng t

lin kt C H to H2.
Nhit cao, p thpnhiu sn phm kh.
Nhit va phi (450 530 oC), p sut caot gia mchnhiu sn
phm lng.
C ch: Theo Rice n xy ra theo c ch gc t do:

Nh vy, cracking nhit to ra mt lng ln etylen, sn phm thu c t

nhnh, khng nhiu phn ng ng phn ha, kh thu c sn phm vng, v vy m
xng thu c t qu trnh cracking nhit c tr s octan thp.

b) Bin i ca olefin
Nhit thp, p sut cao olefin d trng hp. Nhit tng phn ng
phn hu tng. Ngoi ra,olefin cn tham gia phn ng ngng t, ankyl ho vi
naphten to thnh nha v cc.
6

c) Bin i ca naphten
u tin xy ra cc phn ng sau:

Kh nhnh ankyl

Kh hydro olefin vng Aromatic

Phn hu naphten a vng n vng.

Kh naphten n vng parafin + olefin / diolefin.

To nhiu sn phm lng v no hn so vi nguyn liu v parafin.

d) Bin i ca hydrocacbon thm

nhit cao, theo quy lut sau:

Kh nhnh ankyl.

Ngng t vng cc (cacboit). Tc hi ca cc:

+ Gim tc truyn nhit.
+ Gim nng sut bm.
+ Tng chi ph vn hnh.

e) S bin i ca hp cht lu hunh

Cc hp cht lu hunh nm trong nguyn liu di dng mercaptan ni
chung cc hp cht lu hunh c bn nhit km..v mt s bn nhit nh
benzoliophen, khi phn hy to ra H 2S. Khng mong mun nhng hp cht ny c
trong sn phm.

3) QU TRNH CRAKING NHIT

a) Nguyn liu

Phn don mazut ca chng ct kh quyn.

Gasoil nng ca qu trnh cracking xc tc.

Cn nng ca qu trnh lm sch (DAO).

b) Sn phm ca qu trnh cracking nhit

(1) Kh
7

Sn phm kh cha nhiu hydrocacbon olefin v cn c th cha H 2S . kh

cracking cn cha mt lng ln nhng hp cht khng no ch yu, cn ca qu trnh
cracking nhit cn c s dng lm nhin liu t l. Mt s c nhp chung vi
cn gurdon v nhng sn phm khc lm nguyn liu cho l hi v nguyn liu ban
u cho qu trnh coking.
(2) Xng
Khc vi xng chng ct trc tip c hm lng parafin l ch yu, xng ca
qu trnh cracking nhit cn cha c olefin trong olefin c 1 ni i hoc aren c
cha nhnh olefin chim a phn. V vy xng cracking nhit tr s octan MON =
68-72 cao hn so vi xng ca qu trnh chng ct trc tip(MON=40-45).
Thnh phn ca mt s loi xng(% trng lng):
Loi xng

Olefin

Aren

Naphten

Parafin

12

26

62

Xng chng ct trc tip

Xng cracking nhit t mazut

25-35

12-1

5-8

40-45

Xng cracking nhit t gasoil

40-45

18-20

15-20

20-25

Xng Reforming nhit

19-20

14-16

27-32

33-37

Trong thnh phn ca du m khng cha olefin chnh v th nn xng i t

qu trnh chng ct kh quyn s khng c thnh phn ca olefin. i vi xng i t
qu trnh cracking nhit t gasoil c thnh phn olefin kh cao do gasoil ly t qu
trnh cracking xc tc nn thnh phn olefin ca xng sau khi cracking nhit cao gp 2
ln so vi xng i t qu trnh cracking nhit t mazut.
Xng cracking nhit cha nhiu olefin nn c bn km, di tc dng ca
nh sng v nhit , cc phn t olefin d b ngng t, polymer ha, trng hp ha
to nha. xng cha nhiu olefin d b bin i thnh mu sm. Xng cha nhiu
olefin lm tng ch s octan nhng cng lm cht lng khng tt do cc olefin ny c
cha lin kt linh ng nn d b chuyn ha (oxi ha) bi oxi khng kh (khi tn
tr).
Hm lng lu hunh trong xng cracking nhit cao dao ng trong khong
0.5 n 1.2 %.
8

4) CC YU T NH HNG V S CNG NGH

a) Cc yu t nh hng
(1) Nhit
Nhng thng s cng ngh quan trng nht nh hng n qu trnh cracking
nhit l nhit , p sut v thi gian phn ng. khi tng nhit , tc cracking tng
ln theo quy lut hm s m. Trong khong nhit chn trc, s thay i cc thng
s v nhit v thi gian phn ng c tc dng tng h ln nhau. gi cho su
bin i l nh nhau, khi tang nhit cn thit phi gim thi gian phn ng. i
lng nhit phn ng l thng s rt quan trng. Khi tng nhit , tc phn
ng phn hy tng ln v ngc li, khi gim nhit tc phn ng trng hp li
tng ln. Gim nhit cracking s lm gim tc ca phn ng a t. Nh vy,
tng hiu sut cc sn phm phn hy (kh, lng) v gim hiu sut cc sn phm a
t (cn nha cc) cn thit phi gi nhit phn ng cao ng vi thi gian phn ng
thch hp. l nhim v chnh ca qu trnh cracking nhit; cn i vi qu trnh
cc ha, y sn phm chnh l cc, th qu trnh c hiu sut tt ch khi nht
phn ng nm trong khong va phi.
(2) p sut
p sut xc nh trng thi pha ca h cng nh chiu hng v tc phn
ng. p sut khi cracking phn on gasoil nh cn phi m bo trng thi lng ca
cc tc nhn phn ng, bi v trng thi lng to iu kin tt cho qu trnh trao i
nhit, khng xy ra s qu nhit cc b, s to cc l cc tiu, cn hiu sut xng l
cc i. Nu cracking cn nng, cn phi gi cho h thng trng thi pha hn hp
hi-lng.
Khi cracking xy ra trong pha lng vi nguyn liu nng nh mazut, gudron th
p sut khng nh hng nhiu. Khi p sut v nhit cng cao, v tr t mch
nghing v cui mch, iu dn n lm tng hiu sut sn phm kh, sn phm
lng gim. Cn nu ch c p sut cao th v tr t mch C - C xy ra gia mch,
dn n hiu sut sn phm lng tng.

Nhit cng cao, p sut cng thp th pha kh s cng nhiu, tc dng
trong l ng cng ln v cho php gim s lng ng cc trong cc ng xon ca l.
Nhng trong qu trnh vibreaking, nh hng ca p sut khng ln, tng p sut ch
c th lm tng mt cht t nng sut ca thit b. p sut cao thng lm tng nng
ca cc tc nhn phn ng trongpha hi, iu s to iu kin cho cc phn ng
kt hp nh phn ng polymer ha, alkyl ha v hydro ha.
(3) Nguyn liu
Nguyn liu ca cracking nhit ph bin nht l phn on mazt ca chng
ct trc tip, phn on gasoil nng ca qu trnh cracking xc tc hay cn nng ca
qu trnh lm sch. Cht lng ca nguyn liu l mt thng s quan trng xc nh
cht lng sn phm. khi iu kin cracking khng thay i, nu ta dung nguyn liu
c thnh pn khc nhau s cho cc kt qu khc nhau. Khi tng gii hn nhit si
ca nguyn liu, tc phn ng cng tng ln:
Nguyn liu
Phn on ligroil
Phn on Kerosen
Phn don gasoil
Phn on xola

Gii hn si, oC
180 220
220 270
270 300
300 350

Hiu sut xng, %kh.l

12.1
14.9
15.8
18.0

(4) Thi gian lu

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

b) S cng ngh v hot ng ca qa trnh cracking nhit

10

Cc thit b chnh ca dy chuyn:

(1) L t (1 v 2)
Trong dy chuyn cracking nhit ngi ta hay dng l ng hai bc: bc x-i
lu loi bung. s cu trc ca l gm hai bung bc x v mt bung i lu.
Trong bung bc x, nhin liu c t chy cp nhit cho l. Ngi ta b tr cc
ng pha trn v di ngn la trc tip nhn bc x, cn bung i lu l nhn
nhit ca kh khi ch yu do truyn nhit i lu. Trong bung bc x, pha trn phaken ca ngn la, ngi ta b tr khong 6 ng vi ng kinh 127x10mm, pha
di ngn la ngi ta b tr khong 30 ng. trong buongf i lu c 84 ng. b mt
t nng tng cng l 900m2 . t, ngi ta b tr 18 vi t dc theo chiu di ca
bung bc x, c np nhin lu kh hoc lng.
(2) Thit b bay hi
Hn hp sn phm bay hi t bung phn ng sang thit b bay hi p sut
cao (55-100atm). phn chia pha trong thit b bay hi th phi duy tr p sut cao
11

phn cn i ra y thit b bay hi cha mt lng ln phn on xng v gasoil ha

tan ln. tch ring phn nh ny ngi ta cho bay hi p sut thp. Nh p sut
thp, mt phn nh c bay hi ra khi phn cn. tng kh nng bay hi phn
di thit b cho hi nc vo. Thit b ny bay hi p sut cao c cu to l hnh
tr t 2-3m, chiu cao l 15-18m. Thit b bay hi p sut thp c trang b cc a
chng ct. N khng nhng ch tch cc cu t nh ra khi cn craking m cn t
nng nguyn liu do nhit lm lnh v ngng t hi cc phn on c tch ra.
(3) Ct tinh ct (8 v 9)
Ct tinh ct l mt hnh tr thng ng c ch to bng thp cacbon pha
ngoi, cn pha trong c lt bng thp mm, bn trong thp c b tr cc a v
c chia lm hai phn bng mt a ic. phn pha trn lm nhim v chng
luyn cn phn pha di ch chng ct cc cu t nh trong cn nng. v ngoi c
cc lp cch nhit v cc ca kim tra s lm vic ca thp v lm v sinh, lp rp
v thay th cc a khc. Khc vi ct tinh ct du th, thp tinh ct ny lm vic
iu kin p sut cao (0.8 1.0 MPa).
(4) Hot ng
Nguyn liu l phn du nng c bm 13 cho qua thit b trao i nhit 11,
vo phn bn di ca thp tinh ct 8, ng thi cho v phn nh ca thit b bay hi
p sut thp 9. T thit b 9, nguyn liu c trn vi phn on gasoil nng v c
a vo y thp 8, dng nguyn liu v phn tun hon c trn vi nhau ri nh
bm 18 cho qua l t nguyn liu nng 1, sau vo bung phn ng 3. Phn on
gasoil thu c a ic ca thp 8 nh bm 19 cho qua l t 2 cracking su
v tip tc vo thit b phn ng 3. T thit b 3, sn phm i vo thit b bay hi p
sut cao 4, y phn nng cracking c tch ra v c cho vo y thp bay hi
p sut thp 9, t thit b ny s tch ra c phn on gasoil. Phn nng c ngng
t v cho quay li tun hon cng vi nguyn liu, cn phn nh c cho qua thit bj
trao i nhit sau i ra khi dy chuyn.
Dng hi t nh thit b 4 c cho vo thp 8, t nh thp 8 tch ra phn kh
v xng, sau c lm lnh cc thit b 5, ri c tch trong thit b tch kh 6.

12

Kh tch ra c dn n dy chuyn phn tch kh, cn xng c cho vo ct n

nh xng, cui cng vo b cha xng.

(5) Cc thng s cng ngh

Nhit

p sut
MPa

L t 1
L t 2

Vo
Ra
Vo
Ra

400 410
450 490
380 390
540 550
470 500

L phn ng 3
Thit b bay hi p sut cao 4
nh thp
y thp
Thp tinh ct 8
nh thp
Gia thp
y thp
Thp bay hi p sut thp 9
nh thp
Gia thp
y thp

4.0 5.5
2.2 2.7
4.0 4.5
2.2 2.8
1.5 2.5

415 430
410 420
0.8 1.2
190 210
275 320
380 410
0.15 0.35
190 195
290 310
380 410

Trn th gii ph bn hn nay l cc dy chuyn cracking vi cng sut t 600

ngn tn/nm n 1800 ngn tn/nm theo nguyn liu. cn vi dy chuyn visbreaking th cng sut thng cao hn, t 800 ngn tn/nm n 2000 ngn tn/nm.

II)CC HA (COKING)
1 GII THIU QU TRNH CC HA
a) Mc ch
Qa trnh cc ho nhm sn xut cc cc t du m t cc nguyn liu l cn
nng nh gudron ,cn ca qu trnh cracking nhit hay cracking xc tc . Qa trnh
ny c tin hnh iu kin nhit t 450-520 oC . Sn phm chnh l cc ,c
dng cho cng nghip luyn nhm , ch to in cc , cho nghnh cng nghip khc
nh cng ngh in t , vin thng. Ngoi ra ta cng thu c cc sn phm khc
nh kh ,xng v gasoil cc ho.
13

b) Khi nim
Qa trnh cc ho l mt dng ca qu trnh cracking nhit .S to thnh cc
l do cc phn ng ngng t cc hydrocacbon to thnh cc hp cht cao phn t c
ngng t vng thm cao . Nh vy nu nh nguyn liu cha nhiu vng no ,
nhiu vng thm ngng t c mch bn di ,l cc cu t d tham gia phn ng ngng
t , s cho hiu sut v cht lng cc tt nht .Kh nng to cc v hiu sut c
nh gi thong qua i lng gi l cc ho Conradson. cc ho ca nguyn
liu cng cao cng cho php nhn nhiu cc hn.

2 PHN LOI
Trong thc t ,cc dy chuyn cng ngh cc ho c phn loi thnh cc ho
gin on , cc ho bn lin tc (cc ho chm) v cc ho lin tc trong lp si
ca cc ht cc.

c) Cc ho gin on.
Cc ha gin on l loi c in v n gin nht. Dy chuyn gm 1 thit b
chnh l ni cc ha, hnh tr c t nm ngang, ng knh t 2-4m v chiu di
10-12m. Nguyn liu c cho vo ni ri c t trc tip nhm nng nhit ,
tch phn nh v to cc. Khi t ti 450-460 oC, sau gim nhit tch phn
nh. Sau tip tc gia nhit t 700-750oC. Khi thy nhit gim th ngng gia

14

nhit v duy tr thm thi gian na hon thnh to cc. Sau c lm lnh n
250oC v tho cc. Chu k lm vic khong 25-35h. Nng sut ti a khong 5 tn.

d) Cc ha chm
*Mt s h thng s cc ha chm.
Hnh 1.1:

Hnh1.2:

*y l cng ngh kh ph bin v rng ri trn th gii. Loi cng ngh ny

phi c t nht 2 bung phn ng(bung cc ha), mt bung lm nhim v phn ng
cn bung kia trong thi gian tho d cc, sau li thay th cho nhau. Nguyn liu
c t nng lin tc trong l ng n nhit 480-520oC; p sut t 2kg/cm2 ri
c np vo bung cc ha. Nguyn liu c gi trong bung cc ha vi thi gian
tch hi hydrocacbon nh v to cc. Khi bung ny np th chuyn sang
15

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

16

*Bng 1:Ch cc ha chm Nga v M

Nguyn liu

Nga

Cn cracking

Cn du m

Gudron

Du
Ty
Xibia

California

Trung
ng

Craking
nhit

T trng

0.9540

1.040

0.9861

0.984

1.083

Hm lng S,%

0.51

2.4

1.6

0.38

0.56

cc ho

8.0

21.0

9.6

11.3

8.6

Kh

9.1

5.0

12.0

6.5

18.1

Xng

10.4

3.0

15.7

16.0

0.9

Gasoil nh

24.7

29.2

35.2

56.5

21.1

Gasoil nng

37.8

27.8

15.5

Cc

18.0

35.0

21.6

21.0

59.9

487

505

496

488

502

0.18

0.4

0.41

0.2

0.34

Thng s

Hiu sut sn phm

iu kin lm vic
Nhit ra khi l t 0
o
C
p sut trong bung
cc ,MPa

e) Qa trnh cc ha tip xc
Qa trnh ny c m phng bng s cng ngh sau

17

Hnh 2: S cng ngh cc ha tip xc

Nguyn liu c t nng trong thit b trao i nhit 10 ,c trn vi phn

tun hon t thp chng ct 13 ,ri bm qua l ng 9 .Nhit t nng trong l t
n 400 oC .Hn hp nguyn liu sau khi ra khi l t c cho vo l phn ng 1
tin hnh cc ha , ngi ta np lin tc cht ti nhit l cc ht cc c nhit 540580 oC , kch thc ht t 3-12mm vo bung phn ng .Do tip xc vi cc ht cc
nhit cao , nguyn liu s tham gia phn ng cracking ,cc ha. Cc to thnh bm
vo ht cc mang nhit lm cho kch thc ca chng tng ln . Thi gian lu ca cc
ht cc trong thit b phn ng ph thuc vo nhit ,p sut trong thit b v
thng c t 6-10 pht , khi p sut trong thit b l 1,5 at v nhit 510-520 o C.
Cc chuyn ng xung ng dn 4 ,ri cho qua phn loi 6 tch cc ht c kch
thc ln hn 12mm ,sau cho qua thit b lm ngui 8 ri ra ngoi lm sn phm.
18

Cc c kch thc ht nh c cho qua l t 7 nng nhit ri a vo trong

bunke 2 . Sn phm hi c cho qua thit b trao i nhit 12 , vo ct tinh ct 13 v
qua cc ct ti bc hi 16,17,18 phn tch thnh cc sn phm : Kh ,xng, gasoil
nh, gasoil nng v cn . Cn c cho tun hon li chu trnh.
*Bng 2: Nng sut qu trnh cc ha tip xc

Nguyn liu
Nng sut

16 tn cc / ngy

Hiu sut sn phm %kh.I

Xng

Gasoil

19.8

16.2

53.5

24

11.4

12.5

49.6

20

14.6

20.0

43.0

T
trng

cc

kh

1.1011

19

1.055

1.028

70 tn cc/ ngy
900 nghn tn cc/nm
f) Cc ha tng si

Hinh 3: s cng ngh cc ha tng si (lp si)

19

Cn
19.5
36.5
22.4

I: nguyn liu, II: xng v kh, III: Gasoil nh,IV: Gasoil nng
Cng ngh cc ha lp si p dng qu trnh lp si ca cc ht cc c nhit
cao khong 480-540oC trong l phn ng S thit b: Nguyn liu i vo oc chia
lm 2 phn, mt phn vo thit b phn ng, mt phn vo thp ra, cc trng thi
tng si c nhit cao t l t sang. Trong thit b phn ng xy ra cc phn ng
cracking nhit v cc ha. Hn hp kh, xng, gasoil t thit b phn ng vo cyclon
tch nhng ht mn v hn hp hi i ln thp ra ra cc ht bi cha tch
c cyclon (thp ra ngc chiu tng hiu sut chuyn ha). Sau hn hp
hi c a vo thp chng ct. nh thp chng ct thu c xng v kh; y
thu c gasoil nng v gia thu c gasoil nh. Cc t thit b phn ng c a
qua l t ( trng thi tng si) nng ln nhit 600 620 oC. Cc ht ln c
cho qua thit b tch, lm ngui v a ra ngoi. Cc mn bay ln theo gp O 2 t my
nn kh cung cp nhit cao cho thit b phn ng. Nhit khi l t cao tn
dng nhit sinh cng.

20

Qa trnh cc ha cc si thng t c nng sut rt cao . Cc ha tng si

c nhiu u im so vi cc ha chm hay cc ha gin on do vi trng thi tng
si trnh c hin tng qua nhit cc b.

3 CC YU T NH HNG
g) Nhit :

Qu trnh tin hnh nhit cao: 400-450oC (c ti liu ghi 400-520oC)

Nhng khng c qu cao v s lm cho xut hin nhiu sn phm phn hy

(kh v lng) v sn phm chnh ca chng ta l sn phm a t (cc).

h) p sut

p sut th ln hn hoc bng vi p sut kh quyn. Khng c tin hnh

p sut qu cao v s xut hin nhiu kh lm th tch tng ln chng li qu
trnh ca chng ta l ngng t-gim th tch.

y l yu t quan trng nht nh hng n qu trnh cc ha.

III) CRACKING HI (PYROLY)

1 MC CH QU TRNH
Sn xut mt lng ln nguyn liu cho cng nghip ha du: ethylene v
propylen, ngoi ra cn butadiene v benzene

1) C IM QU TRNH

L qu trnh cracking nhit cc hydrocacbon paraffine vi s c mt ca hi

nc

Phn ng thu nhit mnh.

Sn phm chnh l hn hp kh gm cc cu t c hot tnh cao (olefin), xng

v du nng.

Sn phm ph gm cc hp cht thm a vng

V vy cn phi lm sch n hm lng ppm.

nghim ngt c c trng bi t l C3H6/C2H4

21

T l C3H6/C2H4 nh : nghim ngt cao i hi nhit ln

=> u tin sn xut Ethylene

2) LNG HI NC

H = lng hi nc / lng nguyn liu (m/m)

H thay i theo phn t lng nguyn liu:

Ethane : H = 0.25 0.4

Naphta : H = 0.5 0.8

Gasoil : H = 0.8 1

Tng ng vi p sut u ra ng phn ng l 1.04 bar ( trnh khng kh lt

vo )

3) NGUYN LIU
NAPHTA

T trng
ng cong chng ct
PI
PF
Thnh phn
n-P
i-P
N
Ar

Nh

Trung
Bnh

Nng

0.65

0.68

0.71

C
C

35
90

44
125

60
175

%m
%m
%m
%m

52
39
7
2

46
31
18
5

32
29
31
8

0
0

22

C3
n-Buthane
i-Buthane
Buthane

BUTHANE
%m
%m
%m
%m

2
58
27
13

Mt s ngun nguyn liu khc: Ethane, Propane, Kerosene, Gasoil, du th...

4) C CH TO THNH SN PHM CHNH

Nguyn liu l C2H6:
Khi mo:
Lan truyn:

t mch:

5) C CH TO THNH SN PHM PH
Cc dng phn ng ph c bn:

Nhit phn cc olefin sinh ra.

Hydro ha v d hydro ha cc olefin sinh ra, to thnh parafin, diolefin, v cc

acetylenique.

Polime ha.
23

To vng v ngng t.

6) S HNH THNH CC HYDRAC,

ETYLENIQUALLENIQUE

24

7) S HNH THNH HYDROCARBURE AROMATIQUE

8) S HNH THNH CC HYDRUACARBURE NNG

9) SN PHM (VI NGHIM NGT = 0.52 )

NAPHTA
%m

Nh

C2
C2H 4
C3H 6
Coupe C4
Butadiene
Coupe C5+
Benzene
Huite

20
34
18
9.5
4.5
17
6
1.5

Trung bnh
17
32
17
9
4.5
22.5
8
2.5 25

Nng
17
29
15
9
4.5
26
10
4

Naphta trung bnh

+ Buthane (75:25)
(%m)
18
31.5
17.5
11
4.5
20
7
2

10)

TIU TH NNG LNG

( Nguyn liu : Naphta trung bnh )
26

Hi nc
Fuel gas
in
Ch s nng
lng tiu th
/TC2H4
/T nguyn liu

Thp
-2 000
6 700
1

T l C3=/C2=
Trung bnh
-2 050
6 400
0.94

cao
-1 950
6 200
0.88

6 600
1 760

6 325
1 850

6 100
1 900

IV) VIS-BREAKING
1 TNG QUAN
Visbreaking l mt qu trnh s dng nhit nhm chuyn ha cn ca qu trnh
chng ct kh quyn (RA: residue atmospherique) hoc cn ca qu trnh chng ct
chn khng (RSV: residue sous-vide) theo con ng cracking nhit thnh kh, xng,
cc sn phm trung bnh v cn c lm gim nht. Cn RA v RSV c np
liu vo thit b gim nht thng thng gim nht ca nhin liu (fuel oil) v
tng hiu sut thu cc sn phm trung bnh trong nh my lc du.
Qa trnh visbreaking thng b gy cc phn t gia mch nhit
khong 4500C vi khong thi gian rt ngn.Cc phn t parafin mch di s b b
gy thnh cc phn t mch ngn hn,phn ng dealkyl s gip b gy cc mch
nhnh ca cc phn t hydrocacbon thm.
i vi cc nh my lc du ngy nay nu ch bin du th nng hn v c
nhu cu cao hn v sn phm th visbreaking cung cp kh nng chuyn ho chi ph
thp m vn tng c sn lng kh ,xng v cc sn phm khc;ng thi lm gim
nht ca sn phm nng FO.y cng l mc ch chnh ca qu trnh visbreaking.
Mc tiu visbreaking:

Gim nht ca dng ngun cp d liu: thng y l cn chng ct chn

khng du th, nhng cng c th l d lng t hot ng hydroskimming,
bitum t nhin t thm trong t hoc ct tar , v thm ch c mt s loi du
c nht du th cao.
27

Gim lng du nhin liu cn li c sn xut bi nh my lc: du nhin

liu cn li thng c coi l mt sn phm c gi tr thp. Nhu cu nhin liu
cn li tip tc gim khi n c thay th ti cc th trng truyn thng ca
mnh, chng hn nh nhin liu cn thit to ra hi nc trong cc nh my
in , sch hn t cc nhin liu thay th nh kh gas t nhin.

Tng t l cc sn phm chng ct gia trong nh my lc du u ra: sn

phm chng ct Trung c s dng nh mt dung mi vi cc loi du cn li
mang li nht ca h xung n mt mc th trng. Bng cch gim
nht ca dng d trong mt visbreaker, du nhin liu c th c thc hin
bng cch s dng t cht pha long v cc sn phm chng ct trung lu c th
c chuyn hng n diesel c gi tr cao hn, sn xut du si m.
Nhng u im ca ca qu trnh l:

Ct gim hm lng lu hunh trong nhin liu.

Tng gi tr ca cc phn on trung bnh s dng lm nhin liu cho cc ng

c diesel

Gi thnh thp hn.

1) NGUYN LIU
Cn ca qu trnh chng ct kh quyn (RA: residue atmosphrique) hoc cn
ca qu trnh chng ct chn khng (RSV: residue sous-vide).

2) SN PHM
Kh, xng, cc sn phm trung bnh v cn c lm gim nht.
C cu sn phm theo ngun nguyn liu t cn du th Rp
Sn phm
Xng
Gasoil
LPG
Tar

%khi lng
6
15
3
76

Trc
visbreaking
28

Sau
visbreaking

 nht
1000C(centistok
es)
T trng(kg/l)

930

115

1,020

1,048

n nh ca sn phm theo chiu tng chuyn ho

3) CNG NGH VISBREAKING

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

29

S cng ngh soaker visbreaking

Trong

qu

trnh vn hnh theo kiu l t,

nguyn

liu

c np vo
thit b gia
thit

nhit

ca

gim

nht

(visbreaker
heater), ti y
nguyn liu c gia nhit n nhit cao, gy ra s ha hi mt phn v s
cracking nh. Dng ra ca thit b ny c lm lnh vi dng gas oil hoc nhng
nhng sn phm y ca thit b phn on lm ngng li cc phn ng cracking.
Hn hp lng hi i vo thit b phn on phn tch thnh kh, xng, gas oil v
cn gim nht (tar). nhng sn phm y sau c trn vi nhng nguyn liu
nh hn (cutter stock) p ng cc tiu chun ca nhin liu trong cc l t. Gas
oil t thit b ny thng c s dng lm cutter stock phi trn vi cn gim
nht.

4) CC YU T NH HNG
a) Nguyn liu
S chuyn ho sn phm cn thnh sn phm nh hn b hn ch bi mt s
c tnh nguyn liu, chng hn nh hm lng asphaltene, natri v hm lng carbon
Conradson. Mt nguyn liu vi hm lng asphaltene cao s cho hiu sut chuyn
ho thp. Ngoi ra ,s c mt ca natri cng nh hm lng cao Conradson carbon, c
th tng t l to cc trong ng gia nhit. Gim thiu hm lng natri v Conradson
carbon s ko di c chu trnh lm vic ca h thng.

30

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

31

b) Nhit

5) CC S CNG NGH IN HNH

Mt thit b cracking in hnh c th lm vic khi gim nht ca dng

thu hi c yu cu v vy nhu cu thnh phn ct cht lng cao c th gim sn
xut mt loi du thng mi t cn FO.
Thit b visbreaking c nhp liu vi cn chng ct chn khng haykh
quyn. Nhp liu dc nng ln n nhit thch hp trong heater. Phn ng c
hco php din ra n chuyn ha yu cu trong soaker trong heater. Dng hi
32

c thm vo cc ng gia nhit duy tr vn tc ti thiu cn thit v thi gian lu

v ngn chn cc ha trong cc ng. Sau khi ra khi soaker, hn hp c lm
ngui trung bnh dng cc phn ng v a n thit b phn tch phn loi.

Hn hp nng c a vo phn tch, mt phn lng chy xung y thp, c

tch bng hi nc sn xut sn phm y. Dng hi bay ln thp, ra condenser
ngng t, sau i n b cha sn phm nh, ti y s tch ra kh, nc c nhiu
lu hunh, v lng c a v hi lu mt phn, phn cn li i n thit b n nh.
Ti mm x gia thit b tch, gas oil c ly ra, mt phn i qua thit b trao i
nhit s b (hay to hi) ri hi lu ln pha trn cao hn, phn cn li vo stripper
bng dng hi ri sau lm mt v thu gas oil hoc trn vi sn phm y t
nht yu cu. Sn phm y c th i qua thit b gia nhit s b cho nhp liu tn
dng nhit.

33

S ny ging vi s u tin ngoi tr sn phm y ca visbreaker c

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

dng

hi

c gom
li ti thit
b

gom

condensate.

Mt thit b cracking nhit c s dng vi mt visbreaker khi mun chuyn

i ti a sn phm nh hay cn gim im chy cc i.

34

35