xuc tac fcc
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M u
S pht trin v tin b ca khoa hc k thut trong cc ngnh cng nghip ha
hc , ha du thc phm c lin quan v gn b cht ch vi vic s dng cc
loi xc tc.
c bit trong ha du cht xc tc ng vai tr quan trng v l nn tng
cho s pht trin ca ngnh.i vi ngnh cng nghip du kh ni chung v lnh
vc lc ha du ni ring, cng ngh xc tc v hp ph c vai tr cc k quantrng, tham gia vo gn nh ton b qu trnh sn xut, quyt nh cht lng
u ra ca nhin liu v nguyn liu cho sn xut cc sn phm ha du . V xc
tc khng ch: To c nhiu sn phm v kinh t hn (gip tng tc phn
ng, n gin ha cc bc phn ng-gim chi phu t, phn ng tin hnh
iu kin trung bnh (T,P thp) gim nng lng tiu th) , m cn gip gim
ng k lng cht thi trong qu trnh ch bin thnh phm, lm sch kh thi
c hi v bo v mi trng (Nng cao chn lc ta sn phm mong mun lm gim lng nguyn liu cht thi khng mong mun, thay th cc nguyn
liu nguy him v c hi).Mt trong s l xc tc ca FCC chim khi
lng ln trong tng s xc tc ca nh my lc du, gn 80% khi lng xc
tc rn v hn 50% gi tr. l loi xc tc chim vai tr quan trng trong ha
du (m thnh phn ch yu l zeolit).
Vy xc tc FCC l g v c ch hot ng ca n ra sao, c vai tr vng dng g trong cng nghip v c bit trong cng ngh ha du, nhm em
lm ti ny lm r cc vn trn.
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Mc lc___________________________________________Trang
M u.3
I.1Tng quan v qu trnh FCC......................................................... 5I.1.a. Qu trnh FCC...................................................................................... 5I.1.b. V tr qu trnh FCC trong nh my lc du........................................ 5I.1.c. S cn thit cn c qu trnh FCC....................................................... 6I.2 - Xc tc FCCI.2.a. Nhng thay i xc tc FCC qua cc thi k:....... 7
I.2.b. Thnh phn xc tc FCCa) nh ngha:.......................................... 8b)Thnh phn xc tc:Xc tc FCC hin i bao gm3 hp phn ch
yu l zeolite, pha nn hot tnh v ph gia.b1. Zeolite ........................... 9I.2.c. Tng quan v Zeolite.......................................................................... 10
c1. Cu trc Zeolite................................................................................. 11C2. Tnh cht ha hc ca Zeolite........................................................... 12C3. Cc kiu Zeolite................................................................................ 12
I.2.d. Cracking vi lp xc tc tng si................................................... 16IIC CH XC TC FCC............................................................................. 19II.1. Cc giai on phn ng trn b mt............................................ 19II.2. C ch phn ng ion cacboni ................................................... 20
II.2.a. Gm 3 giai on chnh sau:.............................................................. 21II.2.b. V d c th........................................................................................ 22II.2.c. Cc sn phm to ra trong phn ng cracking xc tc.................... 25
IIITNH CHT V VAI TR CA XC TC FCC.................................... 28
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III.1. Mt s tnh cht c chng ca xc tc FCC............................. 28 bn mi mn........................................................................................... 28
Tnh cht nh hng n mi mn............................................. 28 Th tch mao qun v s phn b kch thc mao qun............................. 29 bn nhit v bn thu nhit.................................................................... 29 Khi lng ring.......................................................................................... 30III.2. Vai tr chung ca xc tc........................................................... 31
I I I .2.a. Vai tr............................................................................................. 31III.2.b. nh hng ca xc tc n nn cng nghip................................... 32
III.3. Vai tr ca xc tc FCC............................................................. 32IVIU CH XC TC FCC........................................................................ 35IV.1Nguyn nhn gy gim hot tnh xc tc................................. 35
IV.1.a. Nguyn nhn vt l......................................................................... 35IV.1.b. Nguyn nhn ha hc.................................................................... 35
IV.2iu ch xc tc FCC............................................................ 36IV.2.a. Phn loi cc phng php sn xut cht xc tc FCC ........................... 36
IV.2.b. Tng hp cc nguyn liu iu ch xc tc FCC.................... 37B1. Ch to cc zeolit.......................................................................................... 37
Zeolit Y ......................................................................................... 38 Trao i ion.................................................................................. 38
I V.2.c. Quy trnh tng hp zeolite v s cng ngh............................. 42VNH HNG PHT TRIN CA XC TC FCC................................ 47
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VI.1. Tm quan trng ca xc tc FCC............................................... 47V.2. nh hng pht trin ca xc tc.............................................. 48Ti liu tham kho51
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ITNG QUAN V QU TRNH FCC V XC TC FCC
I.1 Tng quan vqu trnh FCC
I.1.a. Qu trnh FCC
Qu trnh FCC c tn khoa hc l Fluid Catalytic Cracking - cracking xc tc
tng si - l mt trong nhng qu trnh quan trng nht trong nh my lc du.
Qu trnh ny kt hp cht ch cc cng ngh nn tng trong cng ngh ha hc
nh qu trnh truyn cht (chng ct), truyn nhit, tng si ....
Carking xc tc l qu trnh chuyn ha cc phn on du nhit caothnh nhng thnh phn c bn c cht lng cho ng c, xng my bay
v distilat trung gian l gasoil.
Xc tc trc y s dng cho qu trnh l hp cht alumino -silicat, cntrong thi gian sau ny s dng xc tc trn c s zeolite tinh th v c
cha kim loi t him.
Hiu qu ca qu trnh cracking xc tc c c trng bng cc tham snh: chuyn ha tng ca nhin liu, hiu sut sn phm cracking v
cht lng sn phm. Trong thng s quan trng nht l su
cracking hay su chuyn ha nhin liu thnh xng, kh v cc.
I.1.b. Vtr qu trnh FCC trong nh my lc du
Nhn chung chc nng ca phn xng FCC th hin nh sau:
Phn xng FCC l nh my sn xut xng. Hin nay khong 45% xng trnth gii c sn xut hoc trc tip t phn xng FCC hoc gin tip t cc
phn xng h ngun ca FCC nh l alkyl ha
Phn xng FCC dng tn thu cc sn phm t cn ca du th. Qu trnh
ny to ra nhiu sn phm nh hn, gp phn p ng nhng nhu cu sn phm
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nh ngy cng tng trn th trng.
To ra tnh uyn chuyn trong s vn hnh ca nh my lc du. Ngha l phn
xng FCC c th c iu chnh cc iu kin vn hnh ti a sn xut
xng, hoc cc sn phm trung bnh (LCO), hoc LPG. S uyn chuyn ny lm
cho nh my c kh nng iu chnh cc mng sn phm ca nh my p
ng nhu cu hp l ca th trng.
+ Phn xng FCC to ra nhiu olefin nh cho cc qu trnh lc du h ngun,
nh l alkyl ha v nhng qu trnh ha du khc nh cc nh my sn xut
MTBE, PE, PP
I.1.c. Scn thit cn c qu trnh FCC
Nhu cu cc phn on nhv trung bnh sn xut xng, du ha,nhin liu phn lc v iezen nhiu hn s lng hin c nu ch
chng ct trc tip t du th.
Do nhu cu v nguyn liu cho ha du nh etylen, propylen, benzen,toluen, xylen...
Do yu cu cht lng xng phi c ch s octan cao.Nhng yu cu trn i hi phi c qu trnh cracking. Qu trnh
cracking bin i cc phn on nng thnh cc phn on nh gip ta
tng hiu sut v s lng cc sn phm nh, tng tr s ctan ca
xng v to ngun nguyn liu cho ha du.
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I.2 - Xc tc FCC
I.2.a. Nhng thay i xc tc FCC qua cc thi k:
bng: cc cht xc tc trong thi k u cng ngh caracking du m.
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S liu nm 1994 (IFP) v vic s dng cht xc tc:
I.2.b. Thnh phn xc tc FCC
a) nh ngha:
Xc tc FCC l loi bt mn c cu trc c kch thc trung bnh khong 65
micromt, v bn cht l mt loi axit rn.
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b)Thnh phn xc tc:
Xc tc FCC hin i bao gm 3 hp phn chyu l zeolite, pha nn hot
tnh v phgia.
b1. Zeolite
Zeolite l hp phn quan trng em n chn lc v hot tnh ca xctc FCC, c CTHH chung l Mex/n[(Al2O3)x.(SiO2)y].zH2O. Hai loi
zeolite c s dng ch yu hin nay l loi Standard-Y (H-Y, RE-Y)
hocUltrastable-Y (USY, RE-USY).
Cc thng s thng c s dng nh gi mt zeolite : kch thc mng c s (UCS), hm lng kim v hm lng t him.
Cht lng ca xc tc phn ln ph thuc vo bn cht v cht lngca Zeolite.
b2. Pha nn hot tnh
Pha nn hot tnh (active matrix)hay cn goi l cht mang: Cht mang ng vai
tr ng k trong cht lng ca xc tc. Cc l rng ca Zeolite qu nh,khng th chocc phn t HC ln khuch tn vo. Mt cht mang hiu qu phi
c kh nng cho php khuch tn HC vo v ra khi xc tc..Cc phn ng
cracking s cp xy ra trn cht mang. Tm acid trn cht mang khng c tnh
la chn cao nh
Zeolite, nhng c kh nng Crack cc phn t ln, nhng phn t khng c kh
nng thm nhp vo cc lrng ca Zeolite.Sn phm l cc phn t nh hn s
c kh nng chui vo cc l rng ca Zeolite.Cht mang c th ng vai tr by
cc nguyn t V v cc phn t mang N c tnh kim. Nhng cht ny c kh
nnglm ng c Zeolite. Nh vy mt trong nhng u im ca cht mang l
lm gi cho Zeolite khng b mt hot tnh sm do nhng tp cht.
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b3. Ph gia
Ph gia thng thng c s dng nh l: ph gia gim pht thi SOx, CO
promoter, ZSM-5, ph gia by kimloi...Cc ph gia thng dng ch yu lcht n v cht kt dnh.
Cht n l loi t st thm vo xc tc lm long hot tnh ca n.Cao lanh
thng c s dng lmcht n ca xc tc FCC.Ngoi ra, cao lanh cn c
s dng lm b khung pht trin cc tinh th Zeolite trnn.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 bomi trngkhuch
tn nhit.
I.2.c. Tng quan vZeolite
Zeolite l thnhphn quan trng nht ca FCC
http://hoahocngaynay.com/vi/phat-trien-ben-vung/hoa-hoc-va-moi-truong.htmlhttp://hoahocngaynay.com/vi/phat-trien-ben-vung/hoa-hoc-va-moi-truong.htmlhttp://hoahocngaynay.com/vi/phat-trien-ben-vung/hoa-hoc-va-moi-truong.html -
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Zeolite nh hng n hot tnh, chn lc v cht lng snphm.N mang n cho xc tc :
Tnh chn lc (Selectivity). Hot tnh (Activity). Cht lng ca xc tc ph thuc phn ln vo bn cht v cht
lng ca Zeolite.
Hiu cu trc ca Zeolite, kiu Zeolite, c ch Cracking v cc tnhcht ca n s gip chn c xc tc tt, ng thim bo c
hiu sut Cracking mong mun.
c1. Cu trc Zeolite
Tm t din l mt nguyn t Si hay Al, 4 nh l 4 nguyn t O. Cc tinh th hp li thnh mng khng gian. Mng khng gian
Zeolite c cc l rng (cn gi l pore) c kch thc khong 8.0
Angstroms.
Nhng l rng lm cho din tch b mt ring ca Zeolite rt ln,khong 600m2/g.
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C2. Tnh cht ha hc ca Zeolite.
Do trng thi OXH ca Si: 4 v Al: 3 nn cc t din c tm l Si strung ha in, cn cc t din c tm Al s mang in tch in tch
m ny s c trung ha bi 1 ion dng.
Dung dch cha NaOH thng c s dng trong tng hpZeolite => Na trung ha in tch - ca t din AL Loi Zeolite ny
c gi l Soda Y hay NaY. Zeolite NaY khong bn thy nhit do
cha nhiu Na. Ion NH4 c dng thay th Na, sau khi sy
Zeolite, NH3 bay hi li H trn Zeolite, do tm acidva l
kiu Bronsted, va kiu Lewis.
Tm acid Bronsted sau c th c trao i bng kim loithim, lm tng mnh ca acid.Cc tm acid ny to nn
hot tnh ca xc tc.
C3. Cc kiu Zeolite
Zeolite dng trong sn xut xc tc FCC c tng hp tZeolite t nhin (faujastite).
C khong 40 loi Zeolite t nhin v 150 loi Zeolitetng hp c bit. Nhng ch mt s Zeolite tng hp
l c ng dng.
Nhng kiu Zeolite c ng dng trong xc tc FCC : Zeolite kiu X Zeolite kiu Y Zeolite ZSM-5,
C3.1. Zeolite kiu X
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Kiu X c SAR(T L Hp Th Ring) thp hn kiu Y. Kiu X c bn nhit v thy nhit thp hn Y (do c nhiu
Na hn).
Km bn vi nhit nn zeolite X thng c s dng lmkh kh, tch CO2, tch O2/N2.
C3.2. Zeolite kiu Y
L Alumosilicat tinh th ngm nc vi cu trc kiu Fajazit vi lxp3 chiu ng nht v c kch thc ca s ~ 8.
C cng thc ha hc: M2/nO.Al2O3.xSiO2.y.H2O (iu kin: x>2 v nl ha tr ca cation kim loi M)
n v cu trc c bn ca zeolit Y l cc sodalit. Sodalit l mt khi btdin ct gm 8 mt lc gic v 6 mt vung do 24 t din TO4 gp li.
a-Cu trc zeolit Y. b- H thng mao qun vng 12 oxy
Zeolite Y c th c cc dng khon t nhin, nhng hin nay ch yutng hp t oxyt silic v oxut nhm, i khi t qu trnh tinh th ha
t st nung
Cc Zeolit Y c a vo xc tc FCC di cc dng khc nhau:
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Trao i mt phn hoc hon ton vi t him, phn cn li c thdecation to cc dng REHY hoc REY.
Bin tnh bng phng php x l nhit v (hoc) x l ha hc to ccdng zeolit decation siu bn: H-USY, RE-H-USY hoc dng
deaiumin: H-DY, RE-H-DY.
Vai tr ca t him ch yu lm tng bn nhit cho tinh th(vizeolit dng decation NH4Y, nhit >500c tinh th c th b ph
hy nhng vi dng REY, nhit >900c vn bo ton c tnh
cht tinh th.
C3.3. Zeolite ZSM-5
C3.3.a. Thnh phn ho hc v cu trc ca zeolit ZSM-5
Zeolit ZSM-5 c pht minh bi hng Mobil t nm 1972. y l loizeolit thuc h pentasil, c m cu trc quc t l MFI
Hin nay 40% cm FCC Ty u s dng xc tc ZSM -5 nhmt ph gia lm tng ch s octan.
ZSM-5 c t l Si/Al = 50, kch thc l xp tng i nh (5.5A 0)hn ch c cc phn t ln i quakhng lm xy ra cc phn
ng cracking( cc parafin nhnh hoc cc Alkyl benzen)ch s
octan lun cao v n nh.
H thng mao qun trong zeolit ZSM -5 ba chiu vi ca s vng 10 oxy,ng knh mao qun trung bnh xp x 5,5 A thuc zeolit c mao qun
trung bnh. Cng thc ho hc ca zeolit Na -ZSM-5 c dng:NanALnSi96-nO192.16H2O (n
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Ph XRD dng bt ca ZSM-5.
Mng tinh th ca zeolit ZSM -5 c to thnh t chui 8 vng 5 cnhm nh mi vng 5 cnh l 1 t din TO4.
C3.3.b. Vai tr ca Zeolite ZSM-5
Vic thm ZSM-5 vo cht xc tc FCC l mt phng php quantrng tng lng alken nh m khng lm tng lng cc v kh.
Thm ZSM-5 dn n s gia tng ch s octan ca gasolin do tng t siso/normal ca cc alkan v alken v tng nng hydrocacbon aromat
trong gasolin. tng hiu sut propen ,tng ng thi c isobuten v
isobutan. gim hiu sut gasolin, gim lng metylpenten, hexan v
heptan.
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Khi ZSM-5 c phi liu trong cht xc tc cracking th s hp ph ccalkyl thm d dng hn nn dn n tng hiu sut bezen.
Zeolit ZSM-5 thc s l mt cht ph tr hiu qu cho xc tc FCC lm gia tng gi tr octan ca gasolin v olefin nh, c bit l propen.
I.2.d. Cracking vi lp xc tc tng si
*Qu trnh cracking c lp xc tc chuyn ng thay th qu trnh
Houdry. Qu trnh phn ng xc tc v ti sinh xc tc c thc hin ccthit b ring bit: thit b phn ng(l phn ng) v thit b ti sinh xc
tc.(l ti sinh). Xc tc lm vic c cha cc chy t l phn ng vo i
ti sinh v sau khi ti sinh li ngc v l phn ng (hoc bng t chy
hoc bng cng bc) to thnh mt chu trnh lin tc. Nm 1942 quy trnh
cracking xc tc gi si (FCC) u tin c a vo hat ng c tn l Up
Flow (model I) hnh 5.1
*Nm 1944 ngi ta tng ng knh ca i phn ng v l ti sinh, tch
hi sn phm c thc hin ngay trong l phn ng v ti sinh xc tc dng
tng si v qu trnh thi cho xc tc chuyn ng t pha di v ly ra ngoi
y l. Dy truyn hat ng nh vy c tn l Dow Flow (Model II) hnh 5.2.
Ngi ta lin tc ci tin thit b v c hng dng ca xc tc. Hnh dng xc
tc ph bin l dng vin hnh cu nhm lm gim s mt mt xc tc v gim s
mi mn thit b v nng cao hiu qu tch ca cycion.
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Hnh 5.1. S FCC Model I Model I, t l xc tc/nguyn liu ch t ti a l 3 nhng model II c
thtng ti a l 10. Hng M.B.Kellog thit k loi cn bng p sut Model III nm 1946, hnh
5.3.
Hnh 5.2. S FCC Model II Hng Standard-Oil (New Jersey) thit k loi FCC mi (Model IV)
hnh 5.4. t ci tin ca Model II v a vo hat ngt 1952.
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Hnh 5.3: s FCC model III
1-Kh, 2. Hi nc, 3. L ti sinh, 4.Kh, khi, 5.Nguyn liu, 6. L phn ng, 7.Ct chng ct phn on, 8.Xng v kh, 9.Hi lu nh, 10.Hi lu,
11. ct bay hi ph, 12.Gasoil nh, 13. Gasoil nng, 14.Cn
Hnh 5.4. S cng ngh FCC Model IV
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II C CHXC TC FCC
C ch phn ng cracking xc tc l c ch ion cacboni. Cc tmhat tnh l ion ccboni c to ra khi cc phn t hydrocacbon ca
nguyn liu tc dng vi tm axt ca xc tc.
Tm axt xc tc c 2 lai: Lai Bronsted (H+) v Lewis (L). Tm Bronsted l khi tham gia phn ng c kh nng cho proton hot
ng (H) cn tm Lewis th thiu electron nn c xu hng nhn
thm in t.
C ch hnh thnh tm hot ngCc trung tm hot ng trn b mt cht xc tc l cc tm axit Bronsted v
Lewis
II.1. Cc giai on phn ng trn bmt.
Gm 4 bc c bn sau:
Bc 1:Hp ph cc ion Hydride trn cc tm Lewis:
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Bc 2:Phn ng gia cc proton t Bronsted vi cc olefin:
Bc 3:Phn ng gia cc ion cacboni sinh ra t bc 1 v 2 vi cc
hydrocacbon bng cch to ra cc ion hydride
cc ion hydr idekhng bn s b phn hy thnh
Bc 4: Nh hp ph
Nh hp ph sn phm: RH, CH3CH=CH2
II.2. C chphn ng ion cacboni
{y l c ch chnh ca cracking xc tc}.
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II.2.a. Gm 3 giai on chnh sau:
Giai on 1: To ion cacboni
V d: trong trng hp i vi cc hydrocacbon mch thng (Alcan):
Giai on 2: Pht trin chui phn ng ca cc ion cacboni.Gm ccphn ng chnh sau:
1/ Phn ng ng phn ha:
Xt i vi v tr -C-C(+); -C-H(+)
Xt i vi s chuyn dch v tr ng phn ha ca :
;
H3;
2H5
V d:
2/ Phn ng phn hy theo v tr: -C-C v -C-H
{iu kin: s C>=3}
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V d:
3/ Phn ng vi hidrocacbon (RC) ban u.
V d:
Giai on 3 : giai on dng phn ngCc ion cacboni kt hp vi nhau, nhng hay nhn nguyn t hydro ca xc tc
to thnh phn t trung ha v chng chnh l cu t ca sn phm cracking
xc tc.
II.2.b. V dcth
Xt v d cth nh sau:
{vit c ch ca phn ng cracking xc tc ca n-hexan:
CH3-CH2-CH2-CH2-CH2-CH3}
1/ Hnh thnh cc ion cacboni:
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2/ Pht trin chui phn ng:
(A)
A.1. phn ng ng phn ha:
CH3-CH+-CH2-CH2-CH2-CH3 CH3-CH2-CH
+-CH2-CH2-CH3
A.2. phn ng phn hy:
a/ theo -C-H(+)
b/ Theo -C-C(+)
CH3-CH+-CH2-CH2-CH2-CH3
CH3-CH=CH2 + C
+H2- CH2-CH3
C+H2- CH2-CH3 CH3-CH
+-CH3
CH3-CH+-CH3
CH3-CH=CH2 + H
+
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A.3. phnng vi RC
CH3-CH+-CH3 + RC CH3-CH2-CH3 + R+C (C+6H13)
(B)
B.1. phn ng ng phn ha:
CH3-CH2-CH+-CH2-CH2-CH3
CH3-CH
+-CH2-CH2-CH2-CH3
B.2.
Phn ng vi RC ban u.
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3/ Kt thc chui: mt s sn phn to ra v trng nhau, phn ng vi nhau v
phn ng vi
cc sn phm khc kt thc chu trnh phn ng.
II.2.c. Cc sn phm to ra trong phn ng cracking xc tc
Sn phm mong mun:Phn ng ct mch (cracking ),xy ra theo c chion cacboni.
Hot tnh cracking ca cc hydrocacbon gim dn theo th t sau:
Olefin Ankyl Aromatic Ankyl naphten, isoparafinn-parafin,
naphtennhn thm. Sn phm khng mong mun:
Phn ng isomer ho, thng xy ra trc phn ngcracking.
Phn ng chuyn v hydro:
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Phn ng to hydro: do phn ng dehydro ho, xy ra khi c mt ca Nilm cht xc tc.
Phn ng to C1C2: sinh ra do phn ng cracking nhit phn hy.
Phn ng ngng t:
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Bng: nguyn liu v cc sn phm tng ng ca qu trnh cracking xc tc:
Nguyn liu Sn phm qu trnh cracking xc tc
Parafin -Olefin v parafin-Olefin v hydro
-iso-parafin
-Cc hp cht olefin c trng lng phn t thp Olefin -Parafin v dien
-Parafin, naphten v H.C thm-Polyme, cc
Naphten -Olefin
-Cyclohexan v olefin
-H.C thm
Hydrocacbon thm(alkyl thm) -Parafin v alkyl c mch bn ngn-ng phn ha, chuyn v nhm alkyl-Sn phm ngng t v cc.
Phn ng bc 2:Naphten+ Olefin
-Hydrocacbon thm-Parafin
Hydrocacbon thm+Olefin
-Sn phm ngng t v cc
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III TNH CHT V VAI TR CA XC TC FCC
III.1. Mt stnh cht c chng ca xc tc FCC
bn mi mn l mt tnh cht rt quan trng v:
* bn mi mn quyt nh t l b sung xc tc mi v xc tc ang
hot ng, do , nh hng n tnh kinh t ca cng ngh;
*Mc nh hng n mi trng: v xc tc c mi mn km c th
b ph v v thi mt lng bi ng k vo mi trng,
*nh hng n tnh cht linh ng ca cht xc tc trong thit b v s
phn b kch thc khng hp l.
Tnh cht nh hng n mi mn.*Hm lng zeolit, cng nh kiu v hm lng ca cht nn tc ng trc
tip n bn mi mn ca cht xc tc FCC.
*Kch thc tinh th zeolit nh v phn tn cao ca zeolit trong pha nn
to ra bn mi mn tt cho ht xc tc. Hnh th hc ca cc tinh th zeolit
cng c th nh hng n bn mi mn. V d, ngi ta c th thay th cc
tinh th zeolit Y dng tm mt thng thng bng cc tinh th zeolit Y dng a
dt (kt tinh khi c mt ion K) gia tng mi mn ca ht xc tc (G.
Edwards et al. US. Pat. No 4,175,059, 1979).
*Chng loi v lng cht kt dnh cng nh phng php phi trn cht
kt dnh vo cht xc tc cng c nh hng ng k n bn mi mn. Nichung, tng lng cht kt dnh trong ht xc tc lm tng bn mi mn.
Oxytsilic, oxyt nhm v nh hnh v aluminosilicagel thng l cc cht kt
dnh thng dng ca cht xc tc FCC. Chng loi v hnh th hc ca khong
st dng to dng ht xc tc cng nh hng n bn mi mn.
*Cc iu kin sy phun cng nh hng n bn mi mn ca sn
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phm. V d, nhit u ra ca thit b sy phun cao v nng hn hp c c
tc dng tt tng bn mi mn. Trong mt vi trng hp, nng ca hn
hp c tng cng bng cch s dng cc cht ph gia gim nht, nn lm
tng lng pha rn trong vt liu sy phun v do to ra mt cht xc tc c
bn mi mn cc k tt.
* bn mi mn ca ht xc tc c c trng nh lng bi ch s mi
mn,c xc nh bng mt trong cc phng php do cc nh sn xut
ngh. Mt trong cc phng php tiu chun l ASTM D4058.
Thtch mao qun v sphn b kch thc mao qunTh tch mao qun v s phn b kch thc mao qun ph thuc vo thnh
phn,phng php iu ch v s x l nhit v thu nhit cht xc tc.
S phn b kch thc mao qun trong pha nn cht xc tc ng vai tr
quan trng trong s nh hnh tnh cht xc tc. Nucht nn chanhiu mao
qun tng i hp ( 200) th
thng c b mt ring thp, v do , lm gim vai tr xc tc ca cht nn,
ng thi cng lm gim bn mi mn ca ht xc tc.
S phn b kch thc mao qun ca cht nn b bin i khi thm cc cht
khc vo cht nn. V d, thm 35% +40% kaolin vo aluminosilicagel th
ngi ta nhn c mt vt liu c cu trc mao qun rng.
Cc iu kin iu ch cht nn cng nh hng n cu trc mao qun.
Nng ca hn hp t, pH, nhit phn ng, nhit v thi gian lm gi,
s hin din ca cc cation khc nhau u nh hng n th tch mao qun ca
cht nn.
bn nhit v bn thunhitVic duy tr n nh hot tnh v chn lc xc tc trong qu trnh hon
nguyn khc nghit i hi bn nhit v bn thu nhit (N&TN) cao ca cht
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xc tc FCC, ngha l, ca zeolit v ca cht nn. bn N&TN ca zeolit Y
chu tc ng ca t s SiO2/Al2O3, tinh th, dng ion trao i, hm lng ion
natri cn li, v kch thc tinh th. bn N&TN ca zeolit tng vi t s
SiO2/Al2O3tng, tinh th cao v kch thc ht tinh th ln.
Cht nn bn vng m bo mt xp n nh cho cht xc tc trong
qu trnh hon nguyn, ngha l, bo m mt s khuch tn tt cho cc phn t
nguyn liu v cc kh hon nguyn n tn cc tinh th zeolit. Cht nn tng
hp cha nhiu mao qun nh km n nh hn so vi cht nn cha t mao
qun nh. Cc cht nn hot tnh c bn tt duy tr mt cch n nh b mt
ring sau cc x l nhit v thu nhit, do , m bo s n nh ca hot tnh
xc tc.
bn N&TN ca mt cht xc tc c xc nh trong phng th nghim
bng cch x l nhit v thu nhit cht xc tc trong nhng iu kin khc
nghit khc nhau. Sau khi x l, cc tnh cht vt l ( tinh th, b mt ring,
phn b mao qun v tnh cht xc tc) ca cht xc tc c xc nh.
Khi lng ringKhi lng ring ca cht xc tc ph thuc vo thnh phn v phng
php iuch. Cht xc tc c iu ch theo phng php kt tinh "ti ch" t
khong st nung c khi lng ring cao hn so vi cht xc tc c iu ch
vi cht nn bn tng hp. Cht xc tc vi cht lin kt xut pht t sol oxyt
silic hoc t clohydrol nhm c khi lng ring cao hn so vi cht xc tc
cha cht kt dnh aluminosilicat v nh hnh.
iu kin sy phun c nh hng mnh n khi lng ring cht xc tc
vi cht nn bn tng hp. V d, tng nng pha rn trong nguyn liu sy
phun hoctng nhit u ra lm tng khi lng ring ca sn phm sy
phun.
Khi lng ring cao thng biu hin mt bn tt ca cht xc tc,
cng nh xp v th tch mao qun khng cao. Do , khi lng ring cng
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l mt c trng vt l quan trng ca cht xc tc FCC.
III.2. Vai tr chung ca xc tcI I I .2.a. Vai tr
To c nhiu sn phm v kinh t hn: Tng tc phn ng: dn n cng mt thi gian sn xut th mt
qu trnh sn xut s dng xc tc s to c nhiu sn phm hn
qu trnh snxut khng s dng xc tc.
n gin ha cc bc phn ng:gim chi ph u t hn. Phn ng tin hnh iu kin trung bnh ( vi nhit (T) v p
sut (P) thp)gim nng lng tiu th (do cht xc tc lm
gim nng lng hot hanhit cung cp gimtit kim nng
lng)
Gim lng cht thi v thn thin vi mi trng Nng cao chn lc to ra sn phm mong munlm gim
lng nguyn liu cht thi khng mong mun, hn ch to sn
phm ph.
Thay th nguyn liu nguy him v c hi( chng hn: khi xctc chuyn pha cha c pht hin th khi mun alkin ha mt vt
cht no , m mun phn ng xy ra th ta phi tin hnh trong
dung mi hu c (benzen, hexan,) ha tan mt cht phn cc
v mt cht khng phn cc, m cc dung mi hu c gy c
hi, t khi xc tc chuyn pha ra i v pht trin, th ngi ta tin
hnh phn ng ny bng xc tc chuyn pha chuyn cht t mi
trng khng phn cc vo mi trng phn cc.)
Sn xut ra cc sn phm m nu khng c xc tc th khng thsn xut c.
Kim sot qu trnh tt hn (an ton v linh hot hn).
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Thc y s pht trin ca khoa hc k thut v cng ngh.III.2.b. nh hng ca xc tc n nn cng nghip
27 % ca GNP v 90 % ca ngnh cng nghip ha cht c sdng cht
xc tc. c tnh mi nm lng cht xc tc tiu th c gi tr khong 2
t usd.
Cht xc tc chim 2% tng vn u t trong qu trnh ha hc. Cc ha cht c to ra bi cc qu trnh chuyn ha c s dng
xc tc
c gi tr khong 200 t usd.V d:
Cng nghip Hydrogen (coal, NH3, methanol, FT,hydrogen ha
/HDT, fuel cell).
Lc du (Petroleum refining): FCC, HDW,HDT,HCr , REF .
Ha du (Petrochemicals): monomers, bulk chemicals.
Ha cht tinh khit (Fine Chem).
Thc phm (Food): Magarine, butter,
Dc phm; Nng nghip; Dt nhum.
Xc tc mi trng (Environmental Catalysis): autoexhaust,deNOx,...
III.3. Vai tr ca xc tc FCC
Lm gim nng lng hot ha t dn n tng tc phn ng
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V d: Trong phn ng craking xc tc khi c mt xc tc ( nhxc tc aluminosilicat, hay xc tc cha zeolite) khong nhit
t 400 5000C cc olefine chuyn ha nhanh hn 1.103-1.104ln
so vi cracking nhit.
Lm gim nhit cn thit ca phn ng Nhm tit kin nng lng nhit u vo. ng thi trnh to nhiu sn phm kh khi nhit tng
cao, hn ch nh hng n cht lng sn phm (lm
ch s octane khng cao)
Lm cho phn ng xy ra theo chiu c li, chiu thun: dophn ng cracking xc tc l phn ng ta nhit, nn khi
gim nhit v tng p sut th phn ng din ra theo
chiu ta nhit.
Tng tnh chn lc (hng phn ng theo hng cn thit): n c khnng lm tng hay chm khng ng u cc loi phn ng, gip hng
phn ng theo hng c li.
V d: xt chn lc hnh dng ca xc tc chazeolite:
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Vi nhng vai tr trn phc v mc ch cui cng: to ra sn phm(chyu l xang) c ch s octane cao, v mt s sn phm ph nh gasoil nh,gasoil nng, kh(ch yu l phn t c nhnh) l nhng cu t qu cho
tng hp ha du.
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IV IU CHXC TC FCC
IV.1 Nguyn nhn gy gim hot tnh xc tc
Ni chung, s suy gim hot tnh xc tc c th chia thnh hai loi: nguyn
nhn vt lv nguyn nhn ha hc.
IV.1.a. Nguyn nhn vt l
Cc nguyn nhn vt l bao gm s t hp cc tm xc tc, s bt tc cc
mao qun, tn tht (gim) b mt ring...
IV.1.b. Nguyn nhn ha hc
Ng c thun nghch:do s hp ph cnh tranh ca cc tp cht trongnguyn liu. V s hp ph c tnh cht thun nghch nn s suy gim hot tnh
do nguyn nhn ny cng c tnh "thun nghch, ngha l c th khi phc tnh
cht xc tc bng cch kh hp ph cht ng c nh thi kh nit, x l nhit...
Ng c khng thun nghchbi cc tp cht trong nguyn liu. Ng cbi cc kim loi trong cracking xc tc l mt v d in hnh v ng c khng
thun nghch. S suy gim hot tnh ca cht xc tc do ng c bt thun
nghch khng th phc hi bng cc x l vt l hoc ho hc.
T ng c:l s suy gim hot tnh xc tc do cc phn ng mong mun
xy ra. y l nguyn nhn chnh ca s suy gim hot tnh ca cht xc tc
cracking v do cng l l do pht trincc dng thit k' khc nhau v react
v thit b hon nguyn cht xc tc cracking.
Hin tng ng c cht xc tc cracking xy ra do s che ph mt
lp vt liu cacbon ho trn b mt v bn trong cc mao qun cht xc tc.
Vt liu cc l sn phm khng mong mun.
Ngi ta phn bit s to cc theo cc c chkhc nhau.
1. Cc do cn:c to ra do dehydro ho cc phn cn khng bay hica nguyn liu (cc Condrason).
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2. Cc do tp cht kim loi: loi ny c to ra do cc tp cht kimloi trong nguyn liu bm vo b mt cht xc tc, ri tr thnh cc
tm to cc.
3. Cc xc tc:c hnh thnh do cc qu trnh xc tc to ra mt ssn phm v mt l do no (kch thc h nh hc, kh nng khuch
tn...) phi nm li trn b mt xc tc.
4. Cc do nguyn liu:mt s nguyn liu khng kp cracking ngli trong cc mao qun cht xc tc.
IV.2iu ch xc tc FCC
IV.2.a.Phn loi cc phng php sn xut cht xc tc FCCCht xc tc FCC c th c sn xut theo hai phng php chnh:
Cc zeolit c tng hp trc, sau mi phi trn vo cht nn. Zeolit c hnh thnh (kt tinh) trong pha nn khong st t nhin.
Phng php th nht hu nh c tt c cc nh sn xut cht xc tc FCC s
dng. Vi phng php ny c hai iu khc bit:
- Zeolit c trao i ion vi cc cation cn thit, sau mi phi trn vocht nn. Gm cc bc:
(a) tng hp, trao i ion v bin tnh cu trc zeolit,
(b) phi trn zeolit vi pha nn v(c) sy phun hn hp xc tc (zeolit pha nn)
Zeolit c trao i ion sau khi phitrn vi pha nn. Zeolit sau khi tng
hp c trn vo pha nn v sy phun, tip n tin hnh trao i ion.
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IV.2.b. Tng hp cc nguyn liu iu ch xc tc FCC
B1. Chto cc zeolit
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S kt tinh, trao i ion v bin tnh cu trc zeolit Y (RE: cation nguyn t t him).
Zeolit Y
Zeolit Y thng c iu ch dng NaY t ngun silic (ch yu l
silicat natri), ngun nhm (aluminat natri) v hydroxyt natri. Mt scht mm
khi mo cho qu trnh kt tinh NaY cng c thm vo hn hp gel tng
hp zeolit. S kt tinh thng c tin hnh trong mt thit b kt tinh ln, ko
di t 8 gi cho n vi ngy, tu thuc vo ngun nguyn liu ban u, iu
kin kt tinh, tinh th ca zeolit v thnh phn ho hcca zeolit sn phm.
Zeolit sau khi kt tinh c tch ra khi pha lng bng cc my lc ly tmv ra bng nc. NaY c cht lng tt phi c t s' SiO2/Al2O3> 5, b mt
ring khong 800m2/g, tinh th cao (so vi zeolit chun). Tp cht khng
ng k (pht hin bng XRD), kch thc ht c 1 -T- 5^m.
Trao i ionNaY sau khi tng hp c trao i ion vi cc cation t him (RE)
hoc/v vi NH4 chuyn zeolit NaY v dng hot ng v bn thu nhit.
S trao i ion c thc hin trong mt thng trao i ion hoc trong mt my
lc vt ngang. Trong thng, zeolit c ngm vi dung dch cha ion trao i
nhit , pH, nng , thi gian... quy nh. Sau , zeolit trao i ion c
lc v ra bng nc. Trong my lc, zeolit c cho vo cc ngn lc vi dung
dch trao i ion sau c ry kh v ra nc.
Cc mui t him dng cho trao i ion thng c s dng dng
clorua ca hai loi qung tnhin l bastnasit v monazit. Cc t him t nhin
thnggmxeri, lantan, neodym v paraseodym v mt lng t hn ca
samari, gadolini... (bng 3.5)
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Bng :Thnh phn ca qung t him
t him Nomazit (%) Bastnactic (%)
Xeri 46 50Lantan 24 33
Neodym 17 12
Paraseody
6 4
Samari 3 0,5Gadolini 2 0,2
Khc 2 0,3
sn xut cht xc tc FCC, nhiu nh sn xut thng tch bt xeri. Strao i ion c thc hin trong dung dch axit vi pH = 3,5 -T- 5,0 trnh s
kt ta ca cc ion t him trong qu trnh trao i v hn ch s oxy ho
Ce3+
thnh Ce4+
.
Sau khi trao i vi cc ion t him, zeolit Y vn cn cha 3 +6% Na2O.
loi b ht cc ion natri cn li, zeolit li c sy nhanh, nung t 425 +
760oC trong l quay v sau li trao i vi dung dch sulfat amoni. Khi mun
iu ch zeolit Y c mc trao i ion cao vi cc ion t him, ngi ta cth trao i ion 2 ln vi dung dch t him, sau mi ln trao i, zeolit c
sy, nung nhit cao, cc ion t him c th thm nhp vo cc v tr kh
trao i SI, Sr. Zeolit dng RE-NH4Y c th c iu ch bng cch trao i
ng thi vi dung dch cha ion NH4 v t him.
Bin tnh cu trc ca zeolit YZeolit USY
iu ch zeolit USY, NaY c trao i amoni gim hm lng natri
n 3 hoc 4% Na2O. Zeolit c trao i mt phn vi NH4 sau c nung
nhit cao (~760oC) vi hi nc n nh cu trc zeolit v gim bt
lng natri cn li. Trong sn xut cng nghip, zeolit c nung trong cc l
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quay. S trao i ion vi NH4 c thc hin tip tc cho n khi hm lng
natri trong zeolit t n mc thp hn 1% Na2O v c kch thc mng tinh
th c s khong 24,55 0,02. T s SiO2/Al2O3cao, kch thctinh th cs
thp v hm lng natri nh l cc tiu chun c bn trong vic iu ch' xc tc
FCC gia tng gi tr octan.
iu ch zeolit Y c hot tnh xc tc cao hn, ngi ta thng trao i
vi t him, c th l, vi dung dch cc mui clorua t him. Hm lng t
him a vo zeolit tu thuc vo mi quan h gia hot tnh, chn lc
gasolin v s bin i ch s octan.
X l zeolit USY bng axitZeolit USY c x l axit nhm tch Al ngoi mng v cc ion natri cn
li. Vic x l c th c thc hin bng mt dung dch axit hoc bng mt
cht (nha) trao i dng H. iu kin x l c la chn (nng axit, nhit
, thi gian x l...) t n mt hm lng thp ca Al ngoi mng. Thng
thng, ngi ta x l axit to ra mt zeolit c t s SiO2/Al2O3: 6,5 12
ng vi hot tnh xc tc tt nht, hm lng natri gim xungkhong 0,1%
Na2O. USY sau khi c x l axit c th c trao i vi cc cation t him tng hot tnh xc tc.
Zeolit AFSY l zeolit Y c x l (NH4)2SiF6 thng c k hiu l AFSY.
Zeolit ny c ch' to bi hng Union Carbide (Union Carbide Company) v
c hng Katalistiks Company s dng lm cht xc tc FCC di nhn
hiu thng mi l LZ-210. AFSY c iu ch bng cch x l zeolit Y vi
dung dch (NH4)2SiF6 pH xc nh. V qu trnh tch nhm khi mng li
nhanh hn qu trnh silic lp y l trng trong mng, nn tinh th ca
zeolit gim. S suy gim tinh th ca zeolit c th hn ch' mc ti thiu
bng cch khng ch cht ch iu kin thc hin phn ng. Bng cch tng pH
phn ng (trong khong 3 n7) v gim nng (NH4)2SiF6, tc tch nhm
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c th gim. Tng nhit phn ng lm tng tc lp y l trng mng bng
silic.
Hp cht (NH4)3AlF6c to ra v phi loi khi zeolit bng cch ra
nc mt cch cn thn. Bi v hp cht rt c hi cho bn nhit ca
zeolit. T s SiO2/Al2O3c th t c 6/15, tu thuc vo iu kin x l.
Zeolit AFSY, sau , c th trao i vi cc cation thch hp, thng l cc
cation t him.
Zeolit ph tr (ZSM-5)ZSM-5 l zeolit ng vai tr cht ph tr cho cht xc tc FCC lm gia
tng ch s octan ca gasolin. ZSM-5 c a vo cht nn ca cht xc tc
trc khi c trn u v sy phun. ZSM-5 thng c s dng dng trao
i vi NH4, i khi cng dng Zn- ZSM-5, Cd-ZSM-5...
Ngi ta c th s dng ZSM-5 dng mt cht ph tr ring r. Trong
trng hp ny, ZSM-5 c trn vi mt cht kt dnh tr ri sy phun. V d,
mt cht ph tr xc tc ZSM-5 thng mic iu ch vi 25% ZSM-5
trong cht kt dnh tr, c cc tnh cht vt lsau y: kch thc ht = 74 m,
ch s mi mn Davison = 5, b mt ring = 100 m
2
/g, th tch mao qun = 0,41ml/g (Intercat, Technical data sheet for z-cat, 1988).
Cht nn taluminosilicat v nh hnhCht nn c th c iu ch t aluminosilicat v nh hnh. Loi cht nn
ny thay i ng k hot tnh xc tc v gi tr octan ca gasolin. Cht khi u
cho aluminosilicat v nh hnh l aluminosilicagel hoc hydrosol ca oxyt nhm
v oxyt silic. Cht xc tc FCC c ch to vi cht nn aluminosilicat cm t nh cc s hnh 3.13 - 3.16.
Ngun oxyt silic c th l sol oxyt silic hoc dung dch silicat natri c
trung ho vi axit, ngun oxyt nhm l cc hp cht nhm nh sulfat nhm,
aluminat natri hoc oxyt nhm dng hydrat ho. Nc "t" nhn c sau khi kt
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tinh zeolit Y c th c dng lm ngun silic. Bng cch thay i nng ca
cc tc nhn phn ng, pH ca hn hp t ch to xc tc, thi gian v nhit
to gel, thi gian v nhit lm gi gel, ngi ta c th iu chnh c cu
trc mao qun ca cc pha nn. Zeolit c thm vo hn hp t to cht xc
tc sau khi gel c hnh thnh. Vt liu sy phun c trao i ion v ra
bng nc loi b cc ion natri v cc mui cn li. Sn phm c ra, sy
nhit 200 -T- 260oC trong thit b sy quay (sy nhanh).
Cht xc tc vi cht nn t hydrosol aluminosilicat c th c iu ch
theo s hnh 3.14, nhng axit thm vo dung dchsilicat c thay bng dung
dch ca mt mui nhm.
Mt s cht nn khcCho n nay, cc cht nn c trnh by trn u cha oxyt silic v/hoc
oxyt nhm cng vi khong st. Mt s cht nn khc cha cc oxyt, thng
gm 2 hoc 3 oxyt hn hp. Tuy nhin, chng cha c gi tr thng mi, ch tr
cht nn t magnesiosilicat.
IV.2.c. Quy trnh tng hp zeolitev s cng ngh.
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V NH HNG PHT TRIN CA XC TC FCC
VI.1. Tm quan trng ca xc tc FCC
Cracking xc tc (FCC) l mt trong nhng qu trnh quan trng nht ca
cng ngh lc du. Xng t cracking chim khong 30^50% trong thnh phn
xng thng phm. Ngoi ra cracking xc tc cn cung cp mt lng ng k
du DO, LPG, kh nhin liu v olefin nh cho ha du. Trong qu trnh
cracking, cht xc tc ng vai tr c bit quan trng trong vic nh hng sn
phm, nng cao hiu sut v cht lng cc sn phm mong mun. Khng
nhng th, xc tc RFCC cn nh hng ln n hiu qukinh tca ton b
nh my lc du do nh hng trc tip n sn lng cc sn phm chnh ca
nh my. Chi ph b sung xc tc hng ngy v thay th xc tc chim phn
quan trng trong chi ph vn hnh ca NMLD.
Chi ph thay thxc tc FCC(cthtrongNMLD Dung Qut khong 5
triu USD/nm nu chbin 100% du Bch Hv khong 15 triu USD/nm
nu chbin 85% du th Bch Hv 15% du th Dubai) l mt trong nhng
chi ph vn hnh ln nht ca nh my. Ngoi ra li nhun mt i do sdng
loi xc tc khng thch hp dn n c cu sn phm khng t c hiu qu
kinh tti u c thln ti 0,5 USD/thng du (tc hn 12 triu USD/nm) (Oil
& Gas Journal, Oct 14, 1996; 94, 42) v chi ph pht sinh do nh tr sn xut c
thgy thit hi hngp nhiu ln.
Ngoi yu t kinh t, xc tc FCC cn nh hng ti hot ng caNMLD cvphng din an ton v mitrng. Xc tc sdng khng thch
hp sdbu c, thit bslun phi hot ng nhit cao nn dgim
tui th, pht sinh ra nhiu s c trong qu trnh vn hnh nh chy, n, lm
gin on cc hot ng sn xut. Sdng loi xc tc khng thch hp cn c
thdn n vic to nhiu sn phm phc tc dng xu nmi trng ng
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thi cn c thm chi ph u t v vn hnh thit b loi bcc sn phm ph
khng mong mun.
V.2. nh hng pht trin ca xc tc.Vi tm quan trng ca xc tc trn vai tr ca xc tc FCC l c bit
quan trng trong ngnh cng nghip ha lc du. V th cht lng xc tc ngy
cng c ci tin v pht trin ra nhiu li xc tc khc nhau phc v cho qu
trnh cracking xc tc
Hin nay, trn th gii c khong 120 loi xc tc FCC ca cc hng sx
ln, do bc nh gi cc loi xc tc trong PTN trn loi nguyn liu NMLD
ang s dng la chn xc tc ph hp nht trc khi a vo thc t trong
NMLD l htsc cn thit.
Vi cc TB hin i cho php m phng gn ng qu trnh cracking xc
tc trong NMLD, hiu qu ca cc loi xc tc c th c d on chnh xc v
l c s cho vic la chn CXT ph hp.
Hin nay cng nghip lc ha du s dng cht xc tc zeolite siu bn
(USY) cho qu trnh cracking xc tc. Xc tc loi ny c tnh cht c bit: bn
ha, bn c, bn nhit v c hot tnh xc tc v chn lc cao.V th xu hng
hin nay l nghin cu v ch tp xc tc theo hng tng t s SiO2 /Al2O3
xc tc tr thnh siu bn m vn gi nguyn c cu hnh ca n hay ni cch
khc l khng sp cu trc.
Vi nn khoa hc pht trin nh hin nay, cng vi nhu cu cp bch
tng cng cht lng sn phm trong ngnh ha lc du(do ngun nguyn
liu ngy cng cn kin m nhu cu ca con ngi ngy cng tng, khng
cch no khc phi nng cao cht lng sn phm, mun th phi pht trin
cng ngh xc tc mnh m hn) ha hn trong tng lai ngy cng xut hin
xc tc c c tnh cao siu bn nh ZSM-5, USY ,
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Ti liu tham kho
1. Ha hc du m v kh : inh th ng, Nguyn khnh dip hng (Nh xutbn khoa hc v k thut H Ni)
2. Mt s ti, lun vn lin quan n craking xc tc trn trang: tailieu.vn;luanvan.net
3.Ti liu trn dien dan congnghedaukhi.com
(http://forum.congnghedaukhi.com/index.php/topic/1438-xuc-tac-fcc-va-danh-
gia-xuc-tac/#.UpIVicQXHzM)
4.Ti liu trn hoahocngaynay.com
(http://www.hoahocngaynay.com/fr/hoa-hoc-va-doi-song/hoa-hoc-dau-
khi/1747-phan-tich-danh-gia-xuc-tac-fcc-trong-phong-thi-nghiem-lua-chon-xuc-
tac-fcc-cho-cac-nha-may-loc-dau.html)
5.ng hc xc tc: GS.TS. o Vn Tng (nh xut bn khoa hc v k thut
H Ni 2006)
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