kỹ thuật xúc tác - hui - nguyễn Ánh nga

8/13/2019 K thut xc tc - HUI - Nguyn nh Nga

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LOGO


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www.themegallery.com

QUY NH V CCH NH GI IM

im gia hc k c tnh 20%.

im tiu lun c tnh 30%.

im thi kt thc mn c tnh 50%. Trng hp nhng sinh vin thi li (k c thi gia hc phn, kt

thc mn, tiu lun) Nu >4.5 th ch tnh phn thi bng 4.5,cc phn im khc c bo lu).


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GII THIU V NI DUNG MN HC

TT Ni dung Tit

1 Chng 1: Vai tr ca xc tc trong cng ngh ha hc 3

2 Chng 2: C s ca qu trnh xc tc 15

3 Chng 3: Xc tc cng nghip 7

4 Chng 4: Sn xut xc tc cng nghip 6

5 Chng 5: Cc phng php nh gi v nghin cu. 14Tng 45


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TI LIU THAM KHO

Charles N. Satterfields, Heterogeneous Catalysis in Industrial

Practice, McGraw-Hill, Inc., 1991.

Mukhlenov I.P., Dobkina E.I., Catalyst technology, Mir

Publishers, M. 1976.

Mai hu Khim, Bi ging K thut xc tc, NXB HQG TPHCM,2003

Imelik B.,Vedrine J.C., Les techniques physiques dtude decatalyseurs, Editions Technip-Paris, 1988.


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Nguyn nh Hu, Trn Kim Thanh - ng ha hc v xc tc -NXB Gio dc, 1990.

Nguyn Hu Ph - Hp ph v xc tc trn b mt vt liu v c

mao qun -NXB Khoa hc v k thut, H Ni 1998. Phan Minh Tn - Tng hp hu c ha du tp 1,2 - Trng i

hc k thut TPHCM. 1992.

G.M - Chemical kindics and catalysic - Moscow. 1978.

Staley M. Walas - Reaction kinetics for chemical engineers - NewYorkToronto

TI LIU THAM KHO


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CHNG 1: VAI TR XC TCTRONG CNG NGH HA HC


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1.1 LCH S PHT TRIN XC TC.

. T 100 nm trc Phm nhumAntraquinon + acid sulfuric =

acid sulfonicHg

CH4+ O2= CO2+ H2O

Pt,Pd


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1.2 VAI TR CA XC TC .

1835 - Khi nim v cht xc tc v qu trnh xc tc c a ra lnu tin (Berzelius).

1875 - Cht xc tc bt u c s dng trong cng nghip (Platintrong mt lot cc qu trnh nh phn hy H2O2, oxy ho H2, CO, SO2,oxy ho hydrocacbon, ru...).

* ng dng hn ch do hot tnh Pt gim rt nhanh : b u c bi cccht nh As c trong nguyn liu cn tm bin php loi tr Cc qu trnh xc tc khc c a vo ng dng trong cng nghip :

- Oxy ha NH3thnh NO (xt Pt) iu ch axit nitric (1903 -Ostwald)

- Tng hp metanol t CO v H2(1923) ;- Tng hp hydrocacbon t CO v H2(Fischer-Tropsch1930)- Naphtalen thnh anhydride phtalic( 1920)

- Benzen thnh anhydride maleic (1928)

- Oxy ho tng phn etylen thnh oxyt etylen (Union Carbide- 1937


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1.1 LCH S PHT TRIN XC TC.

Trong t nhin lun tn ti cht xc tc ( xc tc men enzimtrong qu trnh iu ch dm n, ru etylic).

Th k 8 - Phn ng ester-ha xy ra nhanh hn nu H2SO4cthm vo mi trng phn ng:

Th k 18 Tc dng ca axit rn trong chuyn ha tinh btthnh ng, t st cho dehyrat ha ru, kim loi cho dehydratha.

Xc tc c s dng trong ch bin du m thnh nhin liu.Ngy nay xc tc cng nghip c tiu th nhiu: aluminosilicatv nh hnh v tinh th (zeolit).


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Tn phn ng Sn phm cui Cht xc tc rn

A. Cc phnngoxy ha kh

1. Oxy ha

SO2+ O2 SO3 H2SO4 Pt, V2O5, Fe2O3

CO + O2 CO2 Lm sch kh. kh v kh thi khi CO hh oxyt : Mn, Cu, Co, Ag, Pt, Pd.

H2, Hydrocacbon + O2 CO2, H2O Lm schkh thi Pt, Pd, CoO, CuO, V2O5, NiO...

mCH4+ nH2O mCO2 + nH2(st.reforming s cp)

CH4 + 3/2O2 CO + 2H2O (steam reform. th cp)

Kh tnghp Ni trn chtmang

CO + H2O H2 + CO2 (chuynha CO) H2 , CO2 Fe2O3+Cr2O3; ZnO+Cr2O3+CuO;..

2. Hydro ha

N2+ 3H22NH3 Amoniac Fe +cc cht xc tin ( K2O, Al2O3, SiO2 CaO..)

CH2=CH2+ H2CH3 -CH3 Lm schkhikh HC khng no Pt, Ni

C6H6+ H2 C6H12 hydrogen ha cc HC thm Ni, Co, Pb, Pt

RS + H2 RH2+ H2S ; RN + H2RH + NH3 lm schSP dumkhicc hpchtS,N

CoMo hocNiMo/Al2O3

CO + 3H2CH4 + H2O (metan ha) Lm schkh Ni + Cr2O3

mCO + nH2 CnH2n+1OH Rubccao Fe, cacbid Fe v cc cht xc tin

CO + 2 H2 CH3OH Metanol ZnO+Cr2O3 (+CuO+K2O)nCO + 2nH2 nH2O + CnH2n (P..F-T) Cc hydrocacbon Co+ThO2+ MgO ;

2nCO + nH2 nCO2+ CnH2n (F-T) ( lm xngtnghp Fe + Cu v ccphgia ;

CnH

2n+ H

2 CnH2n+2 (F-T) v cc chttyra.....) Fe ; Ni ; Cr2O3+ZnO

3. Dehydro ha

C4H10 H2 + C4H8 H2+ C4H6 Butadien Cr2O3; phosphat Ni+Cr2O3

C6H5C2H5 H2+ C6H5CH=CH2 Styren Cc hp cht Fe, Cr, K, Mg, Ca, CuC6H12 4H2+ C6H6 Benzen Pt, Ni


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B. Cc phnngaxit- baz:

1. Polymer ha

nC2H4 [ C2H4]n Polyetylen TiCl4+ AlR3 (xc tc Ziegler-Nata)

nC4H

6 [ C4H6]n Cao su butadien Na, TiCl4+ AlR3 (xc tc Ziegler-Nata)

nC4H

5CH

3[C

4H

5CH

3]

n Cao su isopren TiCl

4+ Al(C

2H

5)3(xc tc Ziegler-Nata)

2. Cracking hydrocacbon

Hydrocacbon (C20 -C25)HCC6 -C12 Nh. liucho ngc Zeolit, Aluminosilicat3. ngphn ha

butanisobutan isobutan AlCl3; AlSi; phosphat

Hydrocacbon n.C5n.C

6i.C

5-iC

6 xngisomer Pt mang trn Al

2O

3hoctrn zeolit Mordenit

4. Alkyl ha hydrocacbon

C6H6+ CH2=CH-CH3 C6H5-CH(CH3)2 Cumen cho snxutphenol H3PO4trn chtmang

C. Cc qu trnh phc tp trn xc tc a chc nng

1. Reforming

Hydrocacbon C7-C9 AromatC6-C9Xng c c.s octan cao; Cc HCthm, BTX cho ha du

Pt, Pt-Re hocPt-Sn trn Al2O3 cClo ha

2. Hydrocracking DuDO, xng Pt, Ni trn zeolit ; Ni-Mo trn Al2O3

Bng 1.1. Cc cht xc tc v qu trnh xc tc


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1.3 ngha ca xc tc trong cngnghip v i sng

Sn xut axit sunfuric:SO2+ O2 = SO3

Hidrat ha to hnh sphm cui cng.

Cht xc tc hin nay l hn hp V2O5+ K2S2O7iu kin phn ng 450 5500C iu ch hir

Ngun nguyn liu r nht iu ch hir l kh thinnhin.CH4 + H2O= CO + 3H2(700-1000

0C, xt Ni)

CO+ H2O= CO2+ H2 (3450C, xt Fe3O4+ Cr2O3)


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Sn xut phn m v axit nitric:

N2 + 3H2 = NH3

Cht xc tc hin nay l Fe + hn hp K2O + Al2O3iu kin phn ng 450 5500C v 300-700 atm

Amoniac c sn xut trn th gii khong 70 triutn/nm, phn ln sn xut phn m, phn cn li

dng sn xut axit nitric bng cch oxi ha NH3



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1.3 ngha ca xc tc trong cng nghipv i sng

Cracking xc tc:

L phn ng chuyn ha cc sn phm nng ca du m thnh xngc nhit si 38-2000C

Hiu sut xng cao hnCh s octan cao hnGim t l FO v kh trong sn phmCht xc tc hin nay 15% zeolit cha t him + 85%

aluminosilicat tng hp v nh hnh

Phng php hin i l tin hnh phn ng theo ch lp siFCC ( phn ng 475-5100C, 0,5-2 atm)

Cracking xtc l quy trnh xtc cng nghip c quy m ln nht. (M mi ngy c 1 triu tn du c ch bin)


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Reforming xc tc:

L qu trnh thc hin mt s phn ng, trong dum chuyn ha thnh HC thm v mch nhnh, nhm

2 mc ch chnh l sn xut nhin liu xng c ch soctan cao v HC thm.

iu kin thc hin 480 - 5200C , 6- 20 atm

Phn ng chnh: ehiro ha naphten, ng phn hanaphten, ehidro vng ha, ng phn ha parafin.

Cht xc tc ph bin Pt/ Al2O3


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1.4. Lch s pht trin v xu hng citin ca xc tc lc ha du

Vai tr xc tc trong cng nghip ch bin du kh : Du th ban u ch cha khong 5 20% phn on nh (xng),

nh cc qu trnh ch bin c xc tc (cracking xc tc, reforming xc tc ngphn ha...) thu ti 75%xng c cht lng caohn ban u rt nhiu.

Nh c xc tc (kim loi v oxyt), t du m, than v kh t nhin thuc cc sn phm nh BTX, olefin nh...l cc nguyn liu quan trng cho ha du sn xut ra cc polymer, cht do, nha, cao su phc v cho kinh t v i sng

con ngi. Qu trnh xc tc cn ng vai tr quan trng trong sn xut cht ty ra,phm nhum v dc phm....

Chuyn ha xc tc metan vi hi nc thu c Kh tng hp (c thnh phn mCO+ nH2)vi hi nc To nguyn liu cho hng lot qu trnh sn xut khc(u l qu trnh xc tc) thu cc sn phm c gi tr s dng cao nh : metanol,hydrocacbon, amoniac, cht ty ra, ru bc cao.( Thay i cht xc tc v thay i cc iu kin cng ngh c th a dng ha cc

sn phm vi thnh phn v tnh cht khc nhau vi cc nh hng s dng khcnhau).

Xc tc hin i vi yu cu v mi trng : Cc qu trnh xc tc loi b chtc, lm sch kh thirt c quan tm. Cc qu trnh t cc thnh phn c hitrong kh thi nh hydrocacbon, CO, NOX, SO2...thnh CO2v H2O c s dngrng ri vi s c mt ca cc xc tc Pd, Pt...


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1.4. Lch s pht trin v xu hng ci tinca xc tc lc ha du

Xu hng ci tin ca xc tc lc du :

Cc cht xc tc cho cc qu trnh lc ha du ngy cng c ci tin theo hngp ng cc yu cu cng ngh mivyu cu v cht lng sn phm

Tin phong trong lnh vc ch to xc tc t vt liu mi (nano...)

p ng nhng i hi ngy cng kht khe hn v mi trng. C th :

- To ra nhiu th h xc tc khc nhau (i vi cc qu trnh c bn ca ch bindu nh cracking, rerorming, ng phn ha ), cng v sau cng t ra u vit hn vhot tnh xc tc(cho chuyn ha chung tng cao) hoc v la chntheohng sn phm mong mun (cho xng thnh phn c ch s octan cao hn) v bn ha hc.

- Mt khc, trong thnh phn xc tc ngi ta a thm ccph gia lm gimlng kh thi SOx, NOx ...


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Vai tr ca xc tc trong qu trnh lc ha du1.2. Mi tng quan gia cng ngh ch bin du kh v xc tc

Cho n ngy nay , hu ht cc qu trnh ch bin du (lc du vha du) u l qu trnh xc tc.

Mt qu trnh cng ngh c gi l qu trnh xc tc nu trong c mt hoc nhiu phn ng xy ra c s tham gia ca cht xctc.

Nu xt v tng th mt qui trnh cng ngh th cng on chuynha xc tc (qu trnh sn xut c xc tc) thc t khng chimnhiu khng gian, thit b khng phc tp, t nhn cng, chi phkhng ln.

Tuy nhin, y l cng on v cng quan trng, mang tnh quytnh cho c qu trnh.


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Cng ngh lc du v xc tc gn b mt thit, hu c. Cngngh lun tm cch p ng trc nhng c th ring ca mith h xc tc ; ngc li, nhng i hi t pha cng nghthc y xc tc phi lun cn ci tin hoc i mi.

V d :- Cng ngh reforming xc tc loi bn ti sinh ph hp

vi h xc tc Pt-Re/Al2O3, trong khi cng ngh ti sinh lintc li c chn cho h xc tc Pt-Sn/Al2O3.

- Cng ngh cracking tng si i vi phn on cn du(cng ngh RFCC), i hi cht xc tc cha zeolit phi citin rt nhiu c pha hot tnh ln pha nn v c cht ph gianhm p ng yu cu kht khe ca cng ngh v c th canguyn liu nng.


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CHNG 2: C S CA QUTRNH XC TC


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2.1 CC KHI NIM CHUNG V XC TC.

S xc tc: Xc tc l hin tng thay i tc do tc dng ca mt s cht. Hin tng bin i tc phn ng ha hc hay kch ng chng do

nhng cht m cui cng vn cphc higi l s xc tc.

c im quan trng nht ca chtxc tc l vi mt lng rt nhchtxc tc , ngi ta c th thc hin vic chuyn ho mt lng rtln cc cht phn ngTnh nng ca chtxc tc ng vai tr ht sc quan trng trong vicnng cao hiu sut phn ng, dn n gim gi thnh sn phm.

Tr cc nguyn t tr, hu ht cc nguyn t ho hc u c th lchtxc tc hoc mt thnh phn ca chtxc tc (dng kim loi, oxit,axit, baz, mui, cc phc cht ...).


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2.2 Phn loi phn ng xc tc:

C ch ca cht xc tc:

Xc tc dng (xc tc) lm tng tc phn ng.Xc tc m (cht c ch-inhibitor) lm gim tc phn ng.Trong thc t, ch s dng cht xc tc thun. Du hiu v pha trong phn ng:Xc tc ng th.(cht xt ha tan cng pha vi cc cht phn ng.)Xc tc d th.(xt tip xc).Xc tc chuyn pha. Cht xc tc to thun li cho s dch chuyn cc

tc cht khc pha c th tip cn nhau phn ng. Cht xc tc c sn trong h phn ng hay cho t bn ngoi vo:Phn ng t xc tc: Qu trnh xc tc xy ra bi cht xt l mt trong

cc sn phm phn ng.Phn ng c dng xc tc. Bn cht ca cht xc tc:Xc tc ha hc.Xc tc sinh hc (enzym).


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2.1 CC KHI NIM CHUNG V XC TC.

- khi phc hot tnh ban u sau mt thi gian s dng, cht xctc cn c ti sinh, hot ha li. Trong mt s trng hp cn bsung thm xc tc mi hoc thay th hon ton.

nh nghasau y phn no th hin ng thitnh c bn - ng dng: Cht xc tc l cht lmtng tc phn ng nhm t ti trng thi cn

bng m khng c s tiu tn ng k v lngtrong sut qu trnh.


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2.3. Cc tc dng chnh ca cht xc tc

H2(kh) + I2(h) 2HI(kh)

Qua thc nghim, ngi ta thy rng:

C xc tc Au: Ehh= 25Kcal/mol C xc tc Pt: Ehh= 14Kcal/mol

Khng dng xc tc: Ehh= 44Kcal/mol

Lm tng tc phn ng nhng khng lm chuyn dch trng thicn bngca phn ng. Lm tng tc ca phn ng c kh nng xy ra(c th ht sc

chm) ch khng th gy nn c phn ng.


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2.4. Cc c tnh ca cht xc tc

Tnh chn lc .( chn lc)

Hot ca xc tc.

Phn bit la chn v hiu sut.

Bo ton thnh phn ho hc, bo ton lng cht

Lm gim nng lng hot ho (Ehh).

nh hng ca iu kin bn ngoi ln s xc tc.

c trng nhit ng hc xc tc

c trng ng hc xc tc


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2.4.1.Tnh chn lc .( chn lc)

chn lc ca xc tc: l t s tc to sn phm so vi tng tc bin i trn c s cht tham gia phn ng theo cc hng khcnhau.

la chn tch phn:

Ik= Gspchnh/ (Gspchnh+ Gspph)


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2.4.2.Hot ca xc tc.

Hot ca xc tc c o bngs bin i lng cht uthamgia phn ng ( hoc lng sn phm to thnh)trong mt n v thi

gianv trn mt n v ca lng cht xc tc.

Hot ca cht xc tc rn tng khi lm tng hot tnh cho mi nv b mt.

Hot thng b thay i trong qu trnh phn ng.


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Lu : Cht xt c th s dng cho mc ch lm tng hot hoc la

chn, i khi c 2 mc ch.Trong trng hp c s a dng v snphm th yu t la chn tr nn quan trng hn.

Hot tnh xt c th c tng ln khi lm tng nhit . Tuy nhin t

tng cao d dn n: rt ngn thi gian sng ca xt, hoc tng thms lng cc phn ng(t,xt) khng mong mun. T cao s lm gim chuyn ha cc i ca cc qu trnh mang tnh ta nhit dokhng thun li v mt nhit ng hc.


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2.4.3Bo ton thnh phn ho hc, bo ton lngcht

Cht xc tc khng b thay i vphng din ho hc cng nh vlng(mt s trng hp, cht xc tc c th b thay i v tnh chtvt l).


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2.4.4.Lm gim nng lng hot ho (Ehh).

Tc phn ng tngl do cht xc tc hng phn ng tin hnh theocon ng mi c nng lng hot ha nhhn

k= k0e-E/RTphng trnh Arrhenius

Phn ng xc tc ng th: k0c trng cho

tn s va chm ca phn t

entropy hat ha

s nh hng ca va chm

Phn ng xc tc d th: k0c trng cho

entropy hot ha

s lng cc trung tm hat ng dn n phn ng

)(. CfkW RTEekk /0.


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Nng lng hot ha

A + B D

A + B AB

AB

D

A + [K] A[K]

A[K] + B AB[K]

AB[K]D + [K]


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Khng xc tc: A + BAB

AB D c k = k0e-E/RT

Khi c xc tc (theo thuyt hp cht trung gian):

A + [K] A[K]

A[K]+ B AB[K]

AB[K] [K] + D c kxt= k0xte-Ext/RT

So snh cc hng s tc phn ng:

Nu gi thit k0xt= k0th hng s tc phn ng thc t lnhn khi khng xc tc mt gi tr l eE/RTln, trong E = E Ext

/

0, 0, /

/

0 0

..

.

xtE RT

xt xt E RTxt

E RT

k e kke

k k e k


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Thc nghim cho thy:

Nu khng c CXTphnng c nng lng hot haEa= 44 Kcal/mol

CXT: AuEa= 25 Kcal/mol

CXT: Pt

Ea= 14 Kcal/mol


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Nhit .Mi cht xc tc c mt khong nhit xc nh m khi n biu hin tc dng ti u gi l nhit thch hp(xc nh thng qua thc nghim).

p sut v nng .S lin quan gia p sut (nng ) vi hng s cn bngphn ng v mt nhit ng hc.

Dung mi.

nht. ho tan ca cc kh vo dung mi. Hng s in mi, axit v baz. S hnh thnh phc, s lin hp v s solvat ha.



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Tc th tch v thi gian lu.

Tc th tch l t s gia th tch kh chy qua cht xc tctrong thi gian mt gi v th tch cht xc tc: Vr= Vkh/gi/Vxt

Thi gian lu gi cht phn ng trn b mt cht xc tc t lnghch vi tc th tch (Vr): tr 1/Vr

Hiu sut th tch - thi gian: t s gia lng sn phm phnngtrong thi gian mt gitrn mt n v th tch cht xc tc.



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2.4.5 c trng nhit ng hc ca phn ng xctc

Phn ng thun nghch: CXT- khng lm thay i mc cn bng - lm cho phn ng mau

t ti trng thi cn bng- lm tng vn tc phn ng - tng vn tc phn ng thun bao

nhiu ln th cng lm tng vn tc phn ng nghch ln bynhiu ln

XT khng bao gi c th thay i iu kin nhit ng hc

ca qtrnh. N ch c th tc ng trong phm vi m nhitng hc cho php.


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2.5.Phn ng xc tc ng th

c trng ca p xt ng th:

KN: Xt ng th l cht xt cng pha vi cc chttham gia phn ng.

P xt ng th ch xy ra trong pha kh v phalng, khng c xt ng th trong pha rn.


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C ch phn ng xc tc ng th

Phn ng xc tc ng th trong pha kh.

Ly phn ng oxy ho SO2vi xc tc NO lm th d:2SO2+ O22SO3

S n gin ca phn ng nh sau:2NO + O2 2NO2

2SO2+ 2NO2 2SO3+ 2NO2SO2+ O2 2SO3

Phn ng ny c p dng trong phng php dng

phng v thp sn xut axit sunfuric trong cngnghip. Phn ng xc tc ng th trong pha lng.

Ph t th t h l


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Phn ng xc tc ng th trong pha lng.

Ly phn ng oxy ho ion thiosunfat bng H2O2vi xc tc lion I-lm th d:

2S2O32-+ H2O2+ 2H

+ S4O62-+ 2H2O

Phn ng xy ra theo 3 giai on v to thnh 2 hp cht trung

gian l IO-

v I2theo c ch sau:H2O2 + I

- IO-+ H2OI-+ IO-+ 2H+ I2+ H2O

I2+ 2S2O32- S4O62-+ 2I-

2S2O32- + H2O2 S4O62-+ 2H2O


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Nt c trng ca phn ng xc tc ng th.

Phn ng xc tc axit baz(axit v baz c tc dng xc tc).

Phn ng xc tc oxy ha - kh(xc tc l cc hp cht ca cckim loi c ha tr bin i).

Phn ng xc tc phc(xc tc l cc phc cht ca kim loichuyn tip).

Phn ng xc tc ng th trong pha khc xc tc bi cckh hot ng ha hc nh NO2, Br2


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Ni dung thuyt Hp cht trung gian

Xc tc tc dng vi cht phn ng to hpcht hp cht trung gian khng bn.

S to thnh hp cht trung gian l qu trnh

thun nghch xy ra nhanh. Hp cht trung gian khng bn, phn hy thnh

sn phm v cht xc tc. Tc ca qu trnht l vi nng sn phm trung gian.


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Thuyt hp cht trung gian

Cht xc tc tng tc vi cht tham gia phnng hnh thnh sn phm trung gian km bn.

S hnh thnh sn phm trung gian l phn ng

thun nghch din ra nhanh. Sn phm trung gian phn hy chm, khng

thun nghch hnh thnh sn phm cui giiphng ra cht xc tc.


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Tc chung ca phn ng t l vi nng casn phm trung gian ch khng t l vi nng cht phn ng.

Nng cht xc tc trng thi t do nm cnbng vi nng sn phm trung gian.


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Thuyt hp cht trunggian

C th c nhiu cht phn ng cng nh nhiucht xc tc ng thi tham gia hnh thnh mtsn phm trung gian. Cc cht xc tc tng tc

nh hn hp xc tc. Mt cht xc tc c th to vi cht phn ng

ng thi nhiu sn phm trung gian.


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Khi tc dng ng thi nhiu cht xc tc, tc chung ca phn ng bng tng tc ca ccphn ng thnh phn.

Cht lin hp ch yu l ion H+v OH-cng cth tham gia vo s hnh thnh hp cht trunggian.

Cht lin hp tham gia hnh thnh hp chttrung gian, lm thay i bn v tc phnhy.


51/255


Phn ng xc tc ng th vi xc tc axit-baz

1.N:Theo Bronsted-

Lowry:

Axit l cht cho proton. Dung dch axit trong nc l

h hai cp tn ti song songaxit-baz nh:

Baz l cht nhn proton. Baz trong dung dch nc

cng tn ti hai cp axit-baznh

bazoaxitbazoaxitAOHOHAH 32

bazoaxitaxitbazo

OHNHOHNH

423


52/255


53/255


Miquan hnproton cthitlptheo l thuytcaLewis l do c stnticpintkhng cpi.

ycpin tcaH2O v NH3 cdng tophn tbn.

H3O+ + OH- H2O + OHH

H3O+ +

NHH

H

H2O + NHH

HH

+

axit

axit bazo

bazo


54/255


Khi SO3 tc dngviH2O, th nc l bazov c in t t do, cn SO3 s dng trn

nn l axit.

OS

O

O

+ OOS

O

O

H

H

+ HOH OHOS

O

O

-

+ OH

H

H+

axit bazo

OH

H

+ HOH OHOS

O

O

2-

+ O

H

HH

+


55/255


2. PHN LOI

Davo bnchtcacc chtxc tc, ngita phnchng thnh cc loixc tc axit-bazsau:

Xc tc axit ctrng

Xc tc axit tngqut (hotha ichtnhcht cho proton

btk,trH3O+), tcl tc dngbixc tc axit Bronsted. Xc tc electrofin khi chtxc tc l axit Lewis.

Xc tc nucleofin khi chtxc tc l bazo Lewis.


56/255


ng hc thuyt hpcht trung gian

Nu cn bng chuyn v pha to cht u, tcl Kc[A]

n


57/255



Phn ng lng phn t

1

2

3

4

*

*

( )

( )

k

kk

k

A K AK

AK B AKB

AKB X Y K


58/255



Ta s dng qui lut nng dng cho trnghp ny

T h phng trnh trn ta suy ra

1 2 3

**

3 4

[AK].[A][K]-k .[AK]-k .[AK][B]=0

d[(AKB) ].[AK][B]-k .[(AKB) ]=0

dt

dkdt

k


59/255


ng hc thuyt hp cht trung gian

Nu k2>>k3[B] th k2+k3[B]k2

phn ng gi bc 2

* 1 3

4 2 3

* 1 34

2 3

k [A][B][(AKB) ]= [K]

k ( [B]

k [A][B]d[A]- [(AKB) ]= [K]dt [B]

k

k k

kk

k k

1 3

2

[A] [K][A][B]dt

k kdk

Tc phn ng xc tc ng th


60/255


p g gt l thun vi nng CXT

k2>> k3 k2


61/255


Cht kch ng

KN:Cht kch ng l cht m bn thn n khng c tcdng xt, khng lm tng tc phn ng, nhng nh cn m cht xc tc c th pht huy ti a kh nng xctc ca mnh.

Tc dng: Khi cho vo mt lng rt nh CK c th tng hot tnh

xt ln hng trm, hng ngn ln.

Lng CK ti u cho mi xt khc nhau th khc nhau.

CK lm gim iu kin khc nghit ca p.

CK lm tng bn ca xt: tng bn c hc, tng bn nhit, tng bn ha hc, gim ng c xt.


62/255


Phn loi cht kch ng:

Cht xc tin kt cu hoc hnh hc :a vo lm gims dnh kt ca cc vi tinh th cht xc tc, khng chochng t li vi nhau thnh cc tinh th ln, t gip

lm tng b mt hot ng ca cht xc tc Cht xc tin in t hoc cu trc : l cht m lm thay

i thnh phn ha hc ca xc tc, thay i c trngin t hoc lm bn cu trc, lm thay i bn cht cc

trung tm hot ng ca xc tc. Cht xc tin chng ng c:Bo v xc tc chng li s

u c bi tp cht hoc bi phn ng ph.


63/255


64/255


65/255


66/255


CHNG 2: C S CA QUTRNH XC TC


67/255


68/255


2 M i b h d h


69/255


2.Mt s c im c bn ca qu trnh xt d th:

1. Tnh c th: Hot tnh xt khng phi l mt tnh cht vn nng ca mt cht no m ch c th c xem xt i vi tng phn ng nht nh.

Vd: cc cht xt sinh hc-cc enzim, ch xt cho chuyn ha nhng hp cht c cuto ging nhau hoc cho chuyn ha ca mt trong s cc ng phn ca cc hpcht .

2. Tnh a nng:

Mt cht c th ng vai tr xt cho nhiu phn ng khc nhau. Vd: aluminosilicat c th hot ng xt cho mt lot cc qtrnh nh cracking, ngphn ha, bt cn i ha, ehirat ha ru. Xt Pt rt hot ng trong cc phnng reforming, ehiro ha, ..

3. Tnh a dng: Thnh phn ha hc ca cc cht rt a dng:

Rt nhiu cc nguyn t trong bng h thng tun hon c th l cht xt hoc thamgia vo thnh phn cht xt. Cht xt c th dng nguyn t, dng hp cht( cc oxit, hp kim, sunfua.,,4. Tnh khng thay i trng thi nhit ng: Xt khng t gy ra phn ng , khng lm dch chuyn cn bng m ch c tc dng

rt ngn thi gian t cn bng

2 Mt i b t h t d th


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5. Tnh cht nhiu giai on:

2 Mt i b t h t d th


71/255



5. Tnh cht nhiu giai on: Thng chia lm 5 giai on: chuyn cht n b mt, hp ph hot

ha trn b mt, phn ng trn b mt, gii hp ph sn phm,chuyn sn phm ra khi b mt

Cc giai on hp ph cht, phn ng b mt, gii hp ph c bn

cht ha hc v xem nh cc giai on to nn phn ng xt. Giai on u( chuyn cht n b mt) v giai on cui(chuyn

sphm ra khi b mt ) khng lin quan n bin i ha hc, l qutrnh khuch tn, qu trnh chuyn khi.

Trong mt s trng hp, nu giai on u v cui l chm hn sovi cc giai on chnh ca p ha hc th tc ca qtrnh xt cquyt nh bi tc khuch tn hay chuyn cht.

Tc ton qu trnh b khng ch bi tc giai on chm nhtgi l giai on quyt nh tc .


72/255


Cht xc tc d th


73/255


Pha hot ng:


74/255


Cc tnh cht ca pha hot ng:

Hot tnh xc tc: hot tnh ng hc v hot tnhthc nghim.

Hot tnh ng hc: x da vo pt tc phn ng

Trung tm hot ng: L nhng trung tm c

ha tr t do ln nn c th hp ph cht phnng v tin hnh phn ng.


75/255


Thuyt Dankov

Mt phn t b hp ph ln b mt cn phi c nhiuTTH cng mt lc tc ng vo th khi mi ko dnc mi ni cc phn t b hp ph v to thnhHCTG, khi phn t mi c kh nng p vi cc phn

t b hp ph khc


76/255


V tr no cng c nhiu mt lm th cng cnhiu lin kt vi cht phn ng v kh nnghp ph dn n p cng cao

V tr hot ng mnh hay yu ty thuc votng loi p.


77/255


CHNG 3 : HP PH

1 h h


78/255


1. nh ngha

Hin tnghpph l gia tngnng

mtschtnhtnh(kh, lng)trn bmt

chtxt so vitrong thtch .

Chtkh hay hicgil chtbhp

ph, cht rn xp dng ht kh hay hi

gi l chthpph v nhng kh khng b

hpphgil kh tr.

Bn cht qu trnh hp ph: L s tngtc gia c phn t vi b mt xc tc. Stng tc ny ng vai tr ch yu trong ccqu trnh xt d th.

2 Phn bit hp ph vt l v hp ph ha hc


79/255


2. Phn bit hp ph vt l v hp ph ha hc

Nhit hp ph Lc hp ph

S chn lc hp ph

Lng cht b hp ph

Tc hp ph

S ph thuc ca nhit

Trng thi cht b hp ph

Tnh cht ca cc mi ni hp ph Tnh thun nghch ca hp ph


80/255


Qu trnh hp ph c ngha c bit trong phn ng

xc tc dth.

Trong qu trnh hpphc tora mtnhitlng,

gi l nhithpph (hoc q Kcal/mol). Bmtcnglntcxpcaxc tc cng cao th nhithpphto

ra cng ln.

Nhit hp ph

Nhit hp ph


81/255


Nhit hp ph

Trong qu trnh hp ph, nng lng t do b mt ca hgim, ngha l G < 0. ng thi hn n ca h gim(docc tiu phn ca cc cht b hp ph trn b mt cht hpph c sp xp mt cch c trt t) ngha l S < 0. Do t phng trnh nng lng ca cng thc GIBBS(Th ng

p ng tch). G = HT.S < 0. T suy ra: H < 0. Ngha l qu trnh hp ph l qu trnh ta nhit. iu ny

hon ton ph hp vi thc nghim. Hiu ng nhit ca qu

trnh hp ph c gi l nhit hp ph.

81

Nhit h h


82/255


Nhit hp ph

HPVL v HPHH u to nhit Nhit to ra do HPVL nh khong t 0 5 Kcal/mol.

Nhit to ra do HPHH kh ln khong t 10 hng trmKcal/mol (tng ng nhit phn ng)..

Lc hp ph


83/255


Lc hp ph

1.Hp ph vt l:

HPVL do lc Van-der waals gy ra gm cc lc:

Tng tc phn t

Lc tng tc tnh in.

2.Hpphha hc:

Trong HPHH lctngtc giachthpphv chtb

hpphl lctngtc ho hc

Lc hp ph


84/255


HPHH: B mt vt rn khng bao gi bng phng l tng m c cc vt nt

gy, hoc to ra cc bc nhy hoc ch li lm

to ra cc ho tr t do trn b

Bmttinh th Bmtvtrn

Lc hp ph

Lc hp ph


85/255


Lc hp ph

Hp ph ha hc

S khng cn bng lc cc nguyn t cht rn kim loi

S khng cn bng lc nguyn t trn b mt cht rn oxit

Lc hp ph


86/255


Lc hp ph

Lc tng tc ho hc trong HPHH bn vng

hnrtnhiuso viHPVL.

Cu trc in t ca phn t b hp ph trongHPHH bin i su do lin kt ho hc hnh

thnh.

S chn lc hp ph


87/255


S chn lc hp ph

HPHH c tnh chtchn lccao, ph thucvo

tnh chtbmtchtrnv tnh chtcachtb

hpph.

HPVL khng c s chn lc, ttc cc bmt

chtrnuc tnh chthpphl hc.

S lng cht b hp ph


88/255


S lng cht b hp ph

HPHH xy ra rt t, khng hn mt lp trn b mt xc

tc (n lp).

HPVL ln bmtxc tc n lphay a lpphthuc

vo bnchthhpph,nhngthngxyra a lp,

nht l khi p sut cn bng gn vi p sut bo ho

(P/Ps1).

S lng cht b hp ph


89/255


S lng cht b hp ph

Khi p sut P cn nh (P/Ps 0,1) xy ra hin tng hp ph n lp.Khi p sut tng ln s xy ra hp ph a lp

Sphthuclngchtbhpphvo P/Ps

Tc hp ph


90/255


Tc hp ph

Tchpphvt l thngnhanh. Cn tchpphho hc

thngxychmdo skhc bitvnnglnghpph.

Khi xt v tc hp ph cn ch n nh hng ca tc

khuchtn, nhtl ivivtliuc mao qun,v trong mao quntckhuchtn c nhhngrtlnnqu trnh hpph.

Tccaqu trnh hpphho hccxc nhtheo phng

trnh

Khp= ko.Z.e-Ec/RT

S ph thuc ca nhit


91/255


S ph thuc ca nhit

Nhittngchai qu trnh HPVL v HPHH ugim. HPVL tinhnh nhitthp(-1930C250C).

HPHH tinhnh nhitcao hn(354000C).

Nhittiucaqu trnh HPHH phthucvo cpchthpphv chtb

hpph.

V d: O2hp ph trn Ptv H2hp ph trn Cu. Ta c 2 ng biu din



92/255



HPVL khng lm thay i trng thi cht b hp ph, vn gi nguyntrng thi ho hc ban u ca n.

HPHH xy ra lm thay i trng thi ban u ca cht b hp ph.

Cht b hp ph c th b phn ly trn b mt cht b hp ph

H2+ 2Me 2MeHCnH2n + 2+ 2Me CnH2n + 1Me + MeH

Cht b hp ph khng b phn ly

Tnh cht ca cc mi ni hp ph


93/255


Tnh cht ca cc mi ni hp ph

HPHH to thnh minibnvngv tnh chtgngingnhminiha hc.

Chng c thl miniha tr,ion, ngha tr...

C sdi chuynin tgiachtbhpphv chthpph,

tcl c tc dngintphnthpphv bmtchtrn. HPVL khng hnh thnh mini.

Stngtc giaphn tbhpphvicc electron cachtrnrtyu.

Giachtrnv phn tbhpphccoi nhl 2 hthng,khng phil mthpchtthngnht.

Tnh thun nghch ca hp ph


94/255


g p p

S gii hp: Hin tng ngc li vi qu trnh hp ph( xy ra khi gim p sut cht b hp ph hoc tng nhit)

Qu trnh hp ph (vt l hoc ha hc) thun nghch :

nu khi gii hp cht b hp ph c gii phng dngban u nh trc khi hp ph.

HPHH khng thun nghch: Nu lin kt gia cht HP vcht b HP tng i bn, qtrnh gii hp c th dn n

s gii phng vo th tch nhng nguyn t cht HP gnkt vi cht b hp ph.


95/255


HPVL bao gi cng l thun nghch: hp ph nh hp ph

HPHH khng phi bao gi cng l qu trnhthun nghch.

Tu theo c tnh mi ni lin kt ha hc mtnh cht thun nghch qu trnh hp ph khcnhau.

C nhng qu trnh HPHH kh bn vng, tothnh cc hp cht ha hc, V d nh s hpph Oxy ln kim loi to Oxyt kim loi, hoc khihp ph ln than cho CO2, CO


96/255


Trng thi HPVL chuyn sang HPHH

HPVL c th l giai on ban u ca qu trnh HPHH v tng th

3.nh lut HPHH- Cc pt biu din HPHH


97/255


p

Hpphngnhitcalangmuir. Trong qu trnh hpphnhngphn tkhbhpphslitrnbmt

htxc tc trong mtthigian nhtnhtipnhnnnglngv thchinqu trnh nhhpph. Qu trnh hpphv qu trnh nhhpphxyra ngthicho nkhi htphnngtctrngthi cnbng.

thitlpcphng trnh nghccho qu trnh hpph,Langmuir

ara mtsiukinsau(thuythpphngnhitcalangmuir). Ttccc tm hotha uc tnh chtnhnhau. Stm hotha khng thay itheo thigian.Mitm hotha chc thhpphmtphn tbhpph. Giacc phn tbhpphkhng c tc ngqua li.

NG HC QU TRNH HP PH L TNG


98/255


NG HC QU TRNH HP PH L TNG

nghcqu trnh hpphcctrngbitc

qu trnh hpphv giihp

Phng trnh Langmuir m tcn bnghpph trn

b mt phng, c thit lp bng phng php l

thuytv c xy dng trn cc quan imvhp

phl tng


99/255


Hp ph l tng

Cc tm hpph(HP) c mcnnglngnhnhau

NhitHP khng itheo gian: Q = const

Cc phn tcHP khng tngtc vinhau Mitrung tm hotngchHP 1 phn t

Trong qu trnh HP v nhhpstm HP khng i


100/255


2.2 Hp ph n cht khng phn ly

A + R AR

Vn tc hp ph: vhA= kh. PA.(1 - A)

Vn tc nh hp ph : vnA

= kn. A Trong :

khs vn tc hp ph

kn: hng s vn tc nh hp ph

PA: p sut ring phn ca A

A: b mt b chim bi A


101/255


trng thi cn bng: vh= vn

/(1 - )= kP

.

1

K P

KP

So snh hp ph phn ly v khng phn ly


102/255


p p p y g p y

ng ng nhit hp ph khi b

phn ly vi gi tr b khc nhaung ng nhit hp ph khi khng

phn ly vi gi tr b khc nhau

Khi h t b h l


103/255


Khi phn t b phn ly

C dng:

Khi bao ph b mtc xc nh:

nii

n

iii

PKPK

/1

/1

.1.

nAAn

.1

K PKP


104/255


CHNG 3 : C TRNG XC TCBNG PHNG PHP HP PH


105/255


3.1 Khi nim v cu trc xc tc rn xp

3.2 ng ng nhit hp ph

3.3 Cc phng trnh ng nhit hp ph


106/255



Ccl

xp

Maoqun

3 1 Khi nim v cu trc xc tc rn xp


107/255



B mt ring ca vt liu (Sr); l tng din tch b mt trn mt gam cht hpph

(m2/g). ivichtkhng c lxpthbmtring khongvi chcm2/g. ivi

chtc lxpv mao mchth n khonghng ngn m2/g.

Th tch l xp ring; l khong khng gian rng tnh cho mt n v khi lng

(m3/g)

Phnbkch thcmao qun

Hnh dng mao qun: mao qunhnh tr,hnh cu,hnh khe, hnh cchai v.v

Phngphp hpphl cng ctm:bmtring, phnblxp,cc dngmao

qunv.v

Phnbkch thccacc mao qunhocphnblxpdatrn nhnggithitv

hnh dng mao qun. Sphnbcxc nhtheo sbinicathtch hoc

bmtcalxpvikch thcmao qun

Bngcc ilngctrngcutrc xpcamtsxc tc rn

Xc tc B mt ring Th tch ring ng knh


108/255


Xc tc B mt ring(m2/g)

Th tch ringca mao qun

(cm3/g)

ng knhmao

qun, Ao

Than hot tnh 500 - 1500 0,6 - 0,8 10 - 20

Silicagel 200 - 600 0,4 15 - 100

Xc tc Ni cho hydro ha 200 - 250 0,3 15 - 200

Aluminosilicat xc tc cho

cracking

300 - 500 0,4 - 0,52 15 - 100

Oxyt Al hot tnh 150 - 200 0,4 20 - 100

Vanadium trn Ba -

Alumosilicat xt oxy

ha SO2

8 - 10 0,4 - 0,5 700 - 1000

Xt oxyt Fe tng hp NH3 7 - 10 0,3 200 - 1000

Xt oxyt Fe oxy ha SO2 3 - 5 0,3 - 0,4 2000 - 4000

Xt Cu nng chy 0,23 0

3 2 ng ng nhit hp ph


109/255



C 2 loi ng hp ph:

ng ng p hp ph: qu trnh hp ph t gi P khng i ch thay i T,

ta v c ng ng p hp ph

x = f(T)P

Dng ny t c gi tr thc t nn t c nghin cu ng ng nhit hp ph: qu trnh hp ph ta gi T khng i v ch thay

i P, ta s xy dng c ng ng nhit hp ph

x = f(P)T

Khi i lng x l hm ng bin vi p sut cn bng P

3 2 ng ng nhit hp ph


110/255



Khi ta tngp sutP tlP/Ps tng(P l p sut

cn bng ti thiim t, Ps l p sutbo ho ca

chtbhpph).

NuP/Ps tngt0 cho n1 th sphthucgiaxv P/Ps l ngngnhithpph.

Nu P/Ps gim t 1 cho n 0 ta c ng ng

nhitnhhpph.


111/255


3 3 Cc phng trnh ng nhit hp ph


112/255



C rt nhiu phng trnh m t mi quan h gia lng cht b hp ph (x)

v p sut cn bng ca pha b hp ph (x - P/Ps).

Phng trnh hp ph Henry: m t mi quan h x-P n gin nht

x = KP x- lng cht b hp ph, hp ph trn 1 gam xc tc (g/g).

P- p sut cn bng ca pha b hp ph (Torr, atm).

K- l hng s Henry.

Phng trnh Henry ch ng vng tuyn tnh nh, tc l vng c che

ph thp, ta gi l vng Henry; khng th p dng c khi nng cao, do

th tch hp ph c hn.



113/255



Phngtrnh ngnhithpphLangmuir: m t cn

bng hp ph trn b mt phng, c thit lp bngphngphp l thuyt; cxy dngtrn cc quan imvhpphl tng.

Cc qu trnh hpphm quan hgia1/v 1/P thomn quan h tuyn tnh l qu trnh hp ph tun theo

phngtrnh ngnhitLangmuir.Tphngtrnh trn ta suy ra cbmtbchim



114/255



Phng trnh Langmuir vit di dng tuyntnh:

KVOA

Vtg

m

m

.

1

1

TVmta xc nhcbmtring ca1g chthpph:

Sr= Vm.NA.Ao

NA: savodro (6,023.1023)

Ao: titdinngang ca1 phn thpph



115/255



Theo l thuyt th gia1/v 1/P l ng thng.

Nhng t nhng s liu

thc nghim cho phng

trnh l ng cong. iuny chng tphng trnh

khng chnh xc lm.



116/255



Nhng hn ch ca thuyt Langmuir

S hp ph c th xy ra theo lp a phn t

Bmtchthpphthngkhng ngnhtvnnglng,tccc vtr hpphc nhithpphkhc nhau.

C th c tng tc phn t ca cht b hp ph thuc cng mt

lp


117/255


THUYT HP PH

A PHN TB.E.T



118/255



Phngtrnh ngnhithpphBET (Brunauer, Emnet, Tellernm1938) l mtthnh cng lnp dngcho hintnghppha

lp.Githitquan trngcaBET l:

Cc githitcaLangmuir cngcngdngvo BET.

Cc phn tbhpphutin c tngtc vinhau tora lc,lcny toiukincho lphpphth2,3...n

Tchpph(ra) trn lphpph th(i), bngvi tcnhhpph(ra) calp(i + 1).

Nhithppht lpth2 trln n lpngngtl bngnhauv bngnhitngngt



119/255



Phng trnh c bn ca BET l:

avdngtuyntnh

V: thtch chtbhpph

Vm: thtch chtbhpphlnnht

Tta xc nhcC v VmSr hpph



120/255



ngngnhithpphv nhhpphtnlpsang alp

Cc dngngngnhithpphctrngcphn loibiIUPAC:


121/255


Cc dngvng trkhc nhau cho cc loivtliuc cutrc m ao qun

trung bnh khc nhau .

Cc phngtrnh hpphngnhit:

Phngtrnh BET

PCIP 1


122/255


Nghin cucutrc xpcaVLMQ:Chnhngvtliuc cutrc v i mao qunv mao

quntrung bnh mithhinsphctptr ong qu trnh hpphvkhhpph. Do

chng ta snhg i 2 loivtliuny.

Cc phngtrnh hpphngnhit:

Vtliuv i mao qun(microp oros i ty ):

Cc zeo li t, t han hottnh, vtliukhong st vnhiuchtmang xc

tc ... c lxpbao gmchyul cc v i mao qun.

Kch thc ca chng xp x vi kch thc ca cc phn t b hpph. Do kch thc vi mao qun v qu trnh thc hin p suttng i nh nn khng c s ngng t hay hp ph a lp trongmao qun . Do khi nh hp ph khng c ng tr.

Vvyphngtrnh BET khng cn ygitrxc nhSr ing

cavtliu.

SmmS PP

CV

C

CV

I

PPV

P.

.

1

.

Cu trc xp trong s xc tc.


123/255


p g

Cutrc xp(lhng)lmttrong nhngctnhquan trngcaxc tc rn,thngchtxc tc rn

c bmtring rtln(hng trmm2/g), nhthan

hottnh 500 1500 m2/g . Cutrc xpphnnh

qua hng lotcc thng s: bn knh mao qun(r),

thtch mao qunvbmtring caxc tc.

Davo cutrc vm phn thnh hai loichnh:

xpvcutrc xp
http://images.google.com.vn/imgres?imgurl=http://www9.ttvnol.com/uploaded2/RatQuanTu/thanhoatinh.jpg&imgrefurl=http://www8.ttvnol.com/forum/SucKhoe/914513.ttvn&h=203&w=259&sz=14&hl=vi&start=13&sig2=NHKFdPk8VN_E9jo0TIr4kw&um=1&usg=__K884QNkt_TyJEnrxNdzOqCvun4E=&tbnid=TLqE8P12kGmkVM:&tbnh=88&tbnw=112&ei=M9HuSLHGDpr2swLLo8XnBA&prev=/images%3Fq%3D%2522THAN%2BXOP%2522%26um%3D1%26hl%3Dvihttp://images.google.com.vn/imgres?imgurl=http://www.tungvan.vn/Produce/asp-html/Anhnhom/fileanh/Impregnated_Activated_Carbon_and_Catalyst.summ.jpg&imgrefurl=http://www.tungvan.vn/Produce/asp-html/danhmuc.asp%3Fmbien1%3D19&h=100&w=100&sz=5&hl=vi&start=186&sig2=W68BmnBOa0J2rTUPJQj3JQ&um=1&usg=__5urIRUxZ0nHgZntxwr2BtuYtsuM=&tbnid=p9lDqOlbBwcLLM:&tbnh=82&tbnw=82&ei=CMzuSNuoKYGEtALM_4XtBA&prev=/images%3Fq%3D%2522than%2Bhoat%2Btinh%2522%26start%3D180%26ndsp%3D18%26um%3D1%26hl%3Dvi%26sa%3DNhttp://images.google.com.vn/imgres?imgurl=http://www.pvc.com.vn/images/stories/vatlieuloc/an.JPG&imgrefurl=http://www.pvc.com.vn/%3Fmodule%3Dcontent%26id%3D31&h=408&w=408&sz=59&hl=vi&start=376&sig2=5VBQcJ4Gbb1GxnO4egcqiQ&um=1&usg=__z-KE_hgvJjTSEFIB4UdQDThfn8w=&tbnid=sycamncpE5XMAM:&tbnh=125&tbnw=125&ei=rMvuSNjQDI6EsgK28MzpBA&prev=/images%3Fq%3D%2522than%2Bhoat%2Btinh%2522%26start%3D360%26ndsp%3D18%26um%3D1%26hl%3Dvi%26sa%3DN


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Zeolit Than anthraxt Than hot tnh

L xp

Vtliumao quntrun g bnh (mesopo ros ity)

Sngngtmao qunvnhlutKelv in

i i VLMQ t b h t t h h h kh i t h
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iviVLMQ trung bnh, trong qu trnh hpph,kh i p sutcn nh

hnp suthibo ha Ps th c xyra hintngchtbhpph

ngngt.

Phngt rnh Kelv in xc nhmiquan hgiatsP/Ps v rk l

bn knh cagitlnghnh thnh bn tro ng mao qun.

Hnnakh i khhpph,sbay hichtlngtmao qunthng

xyra p sutthphnPs . V do ngkhhpphkhng

trng vinghpph. Ssai khc l do p sutmao qun

cntrskhhpphcahingngngnhp suthpph.

TRr

VgfPP

k

L

S ..cos...ln

Tphngtrnh Kelv in c ththyrng: P/Ps caqu trnh thot hi

tmao qunngngtlun l un nhhnP/Ps caqu trnh hpph.

Sphn bkch thctro ng VLMQ t run g bnh

Phngphp cngdngnhiunhtlphngphp caBarrett,


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Joyn er v Halenda, gittlphngphp BJH. N p dngcho nhnh

khhp

ph

trnng

ng

nhit

.

Cscaphngphp lcncvo phngt rnh Kelv in viiukin

cho rng,sau khi b ay hichtlngngngt,chtlngcn lulitrn

thnh mao qunmtmng hpphalpc chiudy t. Chiudy t

cxc nhtheo cng thcsau:

Bn knh camao qunrp ctnh theo biuthc:

r

L

S

Vxt

.

trr kp

Xc nhbmtring caxc tc.

Khng mtqu trnh ngh in cuxc tc dthno hon thnh m khng

h i t b t i h b


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nhgixpcaxc tc, bmtr ing vmcphn bmao qunca

xc tc. nhg i cc ilngt rn phngphp ttnhtl dng

phngphp hpph.

Cng thctnh bmtring caxc tc : mmr SNnS ..

Chtbhpphthngdng didnglng- kh. GitrSm cachtb

hpphkhng phililngtuyti. Hinnay thngdng nhtl kh

trnhN2, Ar, He, Kr...

Mtkhc cngcnhtscthntrngivinhngtrnghpmchtb

hpphc tngtc ha hcvibmtchthpph. Chnh v l do

ngita thnglachncc khtrvnhitthpxc nhbmt

ring. N2 lchtkhcsdngnhiunht. Trong mtstrnghpcn

c skhuchtn tttro ng cc v i mao qun,A r lngcv in smt,sau

l He hocH2. Tuy nh in H2 c thhpphha hc,cn He th kh thao

tcthc

nghim,

do

vic

ng

dng

chngbhn

ch

.

Vicngdngphngtrnh BET tnh bmtring trthnh mt

phngphp tiu chuntro ng n gh in cuVLMQ.

T cc s liu thc nghim xy dng c biu m P/V(P P) ph


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T cc s liu thc nghim, xy dng c biu m P/V(Ps-P) phthuc vo P/Ps s nhn c 1 on thng nh trn hnh v

Phngtrnh BET ni chun g uc thp dngxc nhSr cattcmi

chtrnt rong phmv i g itrP/Ps cachtbhpph= 0,05 0,35 vhng

sC >1.

Xc nhxpcaxc tc.

nhg ixpcaxc tc vchtmang , cbitl xc tc vcht

mang c xpkm, ngita dng phngphp gnng. Dng phng

php ny c thnhg icxpmbngshpphnc. xp

mlilngphnxpso vibmtchung

LnghpphncW tnh th eo cng thc: %100.0

01

g

ggW


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xpmcxc nhtheo cng thc: %100.02

01

gg

ggB

Xc nhxpcaxc tc.

Sphn bmao quntheo kch thcngvai tr qu an trngtrong qu

trnh khuchtn bn trong caphnngha hcxc tc. xc nhphn

bmao qunxc tc theo kch thcthtrchtcnphixc nhkch

thcmao quncaxc tc.

Theo phngphp BJH p dngcho nhnh khhpphtrn ngng

nhit,ta c cng thc: trr k

Trong ,xc nhrk:

khpS

Lk

P

PTR

Vgfr

ln..

cos...

Hai thsau ybiudinsphn bthtch mao quncaA l2O3 v

SiO2


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TrnghpiviAl2O3 c 2 ccitngngvingknh mao qun

l 22 Ao v 41 Ao. iviSiO2 c 1 ccitngngvingknh mao

qunl 50 Ao.


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CHNG 4: XC TC CNGNGHIP


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4.1. Cc yu cu c bn i vi xc tc vn hnh trongcng ngh.


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1/ Hot tnh cao, n nh 2/ chn lc cao. 3/ Thi gian sng ca xc tc phi di 4/ bn ha, bn c, bn nhit cao 5/ Xc tc phi d iu ch v c kh nng ti

sinh c . 6/ Gi thnh hp l .

7/ Xc tc t c vi ngi

4.2. Thnh phn xc tc cng nghip.


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Xc tc cng nghip thng bao gm 2 hocnhiu hp phn i khi rt nhiu hp phn .

Cc vai tr:

cht hot ng xc tc cht kch ng xc tc

cht mang.

Cht mang ( pha nn)


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L phn mang cc pha hot ng xt v xtin,gip tng cng ti a din tch b mt ca phahot tnh nh bn thn c b mt ring ln, gipqu trnh trao i nhit thun li v tng bn

c hc cho xt.

Vai tr v tnh cht chung ca cht mang:


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Mt s tnh nng vt l v ho hc quan trng cn quan tm khi la chncht mang cho xt:

C b mt ring thun li nhm lm tng din tch b mt pha hotng(bao gm xt v xtin), gip cc tiu phn xt c th phn tn v c nhtrn mt cch tt nht.

C xp cao( gm kch thc l xp trung bnh v s phn b l xp) Gip qu trnh trao i nhit thun li, trnh gy qu nhit cc b, ngn cn

s hnh thnh cc tiu phn xt c kch thc ln. Tnh bn trong iu kin phn ng v iu kin ti sinh xt. Tnh cht c hc thun li: chng mi mn, c cng tt, chu lc nn

thch hp. Th hin Tnh tr i vi cc phn ng khng mong mun (ngc li c

th bin tnh thm tnh nng xt thun li cho phn ng mong mun).

Vd: cht mang nhm oxit trong xt reforming, ng phn ho, c x lthm vi axit tng cng chc nng axit-baz ca xt(gip chuyn ha ttcc phn ng mong mun nh ng phn , ng vng ho).

Cht mang cng c th lm thay i hng phn ng.

PHN LOI CHT MANG


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Cht mang c b mt ring nh: diatomit, amian, bt t vi m2/g n vi chc m2/g. Vd: thnh phn v tnh cht bt:

SiO2 60 - 70%

K2O. Na2O 2 - 4%

Fe2O3 13% Al2O3 15 -20%

CaO 23% % l xp 60%

B mt ring 10 m2/g


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Cht mang c b mt ring ln: oxit nhm, silicagel, tst , aluminosilicat, than hot tnhC b mt ring t vitrm n hng nghn m2/g

Cht mang B mt ringm2/g

xp(%)

Than hot tnh 500 - 1500 60-70

Silicagel 200 - 800 20-60

Aluminosilicat 300 - 500 -

Oxit nhm 150 - 200 50-70

Cc ch vn hnh xc tc trong cng nghip


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Lp xc tc tng tnh: c im c bn: Cc lp xt c nh, c sp xp theo dy vi h thng gia nhit

hoc lm lnh trung gian. Kim tra cht ch s thay i nhit t vng tm xt ra ngoi. Dng nguyn liu c np lin tc vo h thng l phn ng (

cha xt) v dng sn phm c ly ra lin tc. Ngng hot ng ton b h thng ti sinh xt ti ch ( i khi a

ra ti sinh ngoi h thng) khi hot tnh xt gim n mt gi tr nhtnh ( hoc t mt trng lng nht nh ca cc bm trn b mtxt)

Cng ngh ny c p dng trong trng hp xt c hnh dng ph

hp, hn ch s mt mt nguyn liu v loi tr s khuch tn hnlon. Xt thng c dng vin bi hoc dng ht n. V d : cc cng ngh hydrogen ha, hydrocracking, ng phn

ha


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Lp xc tc tng ng: p dng trong trng hp xt b gim hot tnh rt

nhanh( bi cc che ph) c im c bn: Lp xt chuyn ng nh nhng, lin tc trong h

thng thit b phn ng. Ton b h thng c vn hnh lin tc.

Lp xt sau khi ra khi h thng phn ng cra ngoi ti sinh ring. Sau c bm trli vo h thng ( t pha u l phn ng).


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Lp xt tng si: p dung trong trng hp khng gii quyt c vn truyn nhitnu s dng lp c nh.

c im: Cht xt dng bt mn (dng vi cu).

Cht xt nng c a vo l phn ng vi tc cao (60 cm/s),c pha trn vi dng nguyn liu ( gia nhit s b) ti ngnng (riser). Ti y, trong vng nhit ha hi ca nguyn liu,bi xt chuyn ng t di ln trn nh mt lp si.

S tn tht p sut nh hn, s truyn nhit tt hn so vi xt tngc nh.

lm vic c tng si cn c s kt hp gia c tnh c hcvi hnh dng xt.

Vd: Cng ngh cracking xt u s dng kiu vn hnh xt tng si.

S gim hot tnh xt:


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Trong qtrnh lm vic thng xy ra hin tng mt hottnh xt tng phn hoc hon ton. Nguyn nhn gy ras mt hot tnh xt:

Do ng c:

S hnh thnh cc: Hin tng thiu kt, s bin tnh thnh phn v cu trc

ca xt v cht mang di tc dng ca nhit hi nc (xt axit, zeolit)

Do to thnh cc hp cht bay hi Do xt b mi mn, tht thot ca cu t hot ng d bay

hi.

Cc cht u c xc tc rn ca mt s qu trnh ha du


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Cht c Cht xc tc

Hp cht cha lu hunh Hydrogen ha, dehydrogen ha, reforming, ng phnha, tng hp methanol, ammoniac, methan ha

Hp cht cha oxi Xt reforming, ng phn ha, polymer ha, alkyl ha

Hp cht cha nit hu c Tt c cc xt axit hoc xt lng chc nng.

Cc hp cht thm a vng Xt axit hoc lng chc

Cc hp cht dng keo ca asphalten Xt HDS i vi cc phn on nng v cn du, cracking

Cc kim P, As

Cc halogen

Xt reforming, hydrogel ha

Xt chuyn ha CO nhit thp, tng hp metanol

Kim loi Ni,V, Na Xt HDS i vi phn on du, xt cracking, xt reforming.

Cc bin php ngn nga:


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Cc phng php ngn nga s ng c xt: Phng php hp ph: Cho hn hp phn ng

i qua ct cha cc cht hp ph mnh.

PP ha hc: Bin cht c thnh cht khngc, ta dng phn ng oxi ha.

Bin php ngn nga s to thnh cc


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Phn tch nguyn nhn, ngun gc to ra cc vcacbon.

S dng cc nguyn t c th ph v gc t do,hoc bng cch a vo cc kh nh hiro , hinc.

La chn cht mang c mao qun ln lmgim thiu hin tng lp kn cc mao qun do

cc v cacbon. Gim lng tm axit mnh bng cch thm cc

ph gia nh MgO, K2O

Bin php ngn nga qu trnh thiu kt do nhit :


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La chn cc iu kin ti u nh nhit , mitrng phn ngNhit cn khng chnghim ngt trnh xy ra hin tng qunhit sinh ra thiu kt cc b.

Gim lng hi nc trong qu trnh p.

B sung vo xt cc cht ph tr c tnh n nhcao.

Qu trnh ti sinh xc tc


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Xc tc c th c ti sinh nhiu ln, nhng khng cxt no c tui th v hn.

Trong qu trnh ti sinh nhng thay i kt cu c- ldn n s suy gim hot tnh xt.

Vic tch t cc kim loi nng As,Pb,Cutrn b mtcht xt l qu trnh bt thun nghch

S mt mt thun ty c hc ( do va p, ri vi trongqu trnh lun chuyn) cng lm tn tht mt lng cht

xt nht nh Xtc mt hot tnh b thi ra nu cha kim loi qu(Pt,Au),

c a vo qu trnh thu hi kl qu sn xut xt mi

4.3. iu ch xc tc


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1/ Xc tc khng c cht mang

1.1/ Xc tc kim loi

1.2/ Xc tc oxyt


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1.1/ Xc tc kim loi


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Phng php kh cc oxyt kim loi

o Tc nhn kh : H2

o Kim loi thu c c hot tnh cao

o Kch thc ht kim loi ph thuc vo iu kin kh

o i vi mi mt loi xc tc th iu kin kh c th khc nhau


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Phng php in ha: tc l iu ch kim loi bng

cch in phn dung dch mui.

1.2/ Xc tc oxyt


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t mui ban u cho kt ta bng baz thuc hydroxyt rn em nung thnh oxyt : iu ch Al2O3 dng Al2(SO4)3 v NH4OH: Al2(SO4)3 + 6 NH4OH = 2 Al(OH)3 + 3

(NH4)2SO4

2 Al(OH)3 = Al2O3 + 3 H2O

Cc yu cu c bn i vi xc tc vn hnh trongcng nghip


153/255


C tnh nng xc tc cao (hot tnh xt cao) Tnh la chn ca xc tc


154/255


CHNG 5: PHNG PHP NGHINCU V NH GI XC TC

1. Phng php tnh:


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Nguyn tc: L phng php tin hnh trong th tchkn cho n khi t c cn bng nhit ng hay nkhi chuyn ha hon ton mt trong s cc cht phnng ban u.

c im : Thng p dng trong iu kin c sbin i s phn t . Phng php cho php theo dinh hng ca p sut n tin trnh phn ng.

u im : Kh nng lm vic vi lng nh cht tham

gia phn ng vi cht xc tc bt k dng no v thuc ton ng ng hc trong mt th nghim viphp o c th t nhy v chnh xc cao.

Phng php tnh


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Khuyt im : Kt qu thc nghim thu c dngtch phn, mun nghin cu s bin i cc thng scn phi tin hnh vi phn.

Do nhc im trn, phng php t c s dngtrong nghin cu xt cng nghip.

2. Phng php dng:


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L phng php ph bin nht nh gi hot tnh xctc.

Nguyn tc: Dng cc cht phn ng c np lin tc(vi vn tc c xc nh vo h thng phn ng ccha lp xt. C th o c v theo di s bin i ca

nng cht phn ng v cc sn phm phn ng theothi gian. c im: L phng php tch phn v lin tc, cho php thc

hin qu trnh gi cc iu kin t ra nh nhit ,nng , p sut, tc di v tc th tch ca dngvo thit b phn ng.


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Phng php dng


159/255


u im:l c th xc nh c hot ca xc tc trng thi n nh ca cht xc tc, cu trc ngin, lm vic lin tc, c th kim tra cht xc tctrong cc iu kin gn vi sn xut

Nhcim:caphngphp l khng c khnngo trc tip tcphnng v kh thchin trongcc iukinl tngcachchyl tng.

3.Phng php dng vi lng:


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L phng php n gin kho st cc phn ng xtd th, c s dng kh rng ri do tit kim xtc vcht phn ng m vn bo m qui lut ng hc caqu trnh.

Dng cht mang tr c sc qua bnh cha cht phnng v mang hi bo ha cht phn ng vo l phnng c lp xc tc. Nng ca tc cht c kim sotbng cch iu chnh p sut hi bo ha ca n trongdng kh mang hoc bng mt phng thc thch hpkhc.

Vi tc dng ln thnh phn ca hn hp phn. ngc th c coi l rt gn vi ch trn l tng


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Nhng u khuyt im rt ra tphng php dng vi lng:


162/255


L phng php tm loi xc tc mi nhanh nhtv t tn km nht (xtc kim loi qu Pt, Pd)

Lng xt dng mi ln th nghim rt nh vlng cc cht phn ng cng rt t.

Phng php ch nghin cu trong phng thnghim khng th p dng vo cng ngh c.

Ptrnh ng hc rt ra t phng php vi lng

l ptrnh vi phn cho s liu chnh xc. Thit b n gin.

4. Phng php dng tun hon


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Nguyn tc: C s tun hon mnh ( nh bm tunhon) hn hp phn ng qua lp xtc. Lng kh tunhon ln hn lng kh tham gia phn ng. Kh phnng c nhp vo v ly ra lin tc.

c im: o c trc tip tc phn ng.

Nh cng tun hon ln loi tr c s thay inhit trong l phn ng.

C kh nng lm vic vi lng xc tc ti thiu. Nhc im: H thng thit b phc tp. Cn lng cht

phn ng ln tun hon. Thi gian phn ng cn lu t trng thi n nh, do d dn ti phnng ph.


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5.Phng php xung vi lng:


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c ph bin nhm sng lc nhanh cc cht xt. Thun tin trong kho st ng hc v c ch

cc phn ng trong trng thi khng n nh. c im : Tc cht c a vo bnh phn

ng khng lin tc m bng cch np nhngxung vo dng kh mang ( kh tr) lin tc thiqua lp xt, ging nh trong phn tch sc k kh.

Sn phm p sau khi ra khi bnh p b gi li

trong by t trong bnh cha nit lng trc khic gia nhit dng kh mang a vo ctphn tch sc k.

PHNG PHP XUNG VI LNG


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Xc nh tnh cht l- ha ca xc tc.


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Tnh cht c hc: Th nghim va p

Th nghim mi mn

Phn b ht.


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CHNG 5: SN XUT CHT XCTC

Mt s cht xc tc s dng trong cng nghip


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NR-2- xuc tac reforming thu kh qua s chuyen hoa metan vi hinc.

Thanh phan: NiO20%; Na2O 0.15%; SO30.5% tren chat mang.

Be mat rieng 18 m2/g, dang khoi tru 12.7 12mm

Thi gian lam viec 4-5 nam.

Toc o the tch toi thieu 200 l/h; nhiet o 838oC; ap suat 1 atm.


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HI-3- xuc tac chuyen hoa CObang hi nc. Thanh phan: Fe2O3-95%; Cr2O3-4%; SiO2-0.2%.

Dang tru, ng knh 6.91, dai 12.7mm

Thi gian lam viec 7 nam.

Toc o the tch 600 l/h; nhiet o 455oC.


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FM-1- xuc tac tong hp amoniac. Thanh phan: 64,6% Fe2O3; 31%FeO; 1,4% K2O; 2.5%Al2O3; 0,5% SiO2.

Dang vien khong qui tac thu c theo phng phap nong chay;96% co kch thc nho hn 10mm va 4% co kch thc nho hn

4mm. Thi gian s dung 7 nam.


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Kim loai nhom Ptdung oxy hoa, hydro hoa va dehydro hoa,

dehalogen hoa.

1. 5% Pt, Pd, Ruva Rdtren phien than hoat tnh, oxyt nhom choat hoa va CaCO3.


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Cac xuc tac dang hat nho va vien (vien thuoc): 0,3% Pt tren

oxytAlhoat tnh co kch thc 3.2mm; 1% Pttren than go cochoa, kch thc 2.4-4.7mm; 0.3% Pttren silicagel.


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Xuc tac dang keo 0.5g Pd/l; li kim loai thanh phan 90 - 10% Pt

- Ph ; muoi en Pt.


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Code-902- xuc tac oxy hoa naphtalen, thanh phan 10% V2O5, 33%K2SO4; 55% SiO2 dang phien, 85% qua ray 1,147mm; 45% qua ray0,074mm.

dang vien (nh vien thuoc) 3.2 3.2; toc o the tch 1400gi1, nhiet o 455oC

Code-904- xuc tac thu vinylclorua t acetylen va HCl. Than hoat tnh (91%); kch thc 1,7 4,7mm tam thuy ngan clorua


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Xuc tac co cac dang hat khac nhau: phien, hat nho, vien, tru, vong, cau


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Chat mang va chat xuc tac tron vao nhau dang ran, sau o

em ep vien thanh hnh dang can thiet.

Chat hoat ong xuc tac c phan bo bang phng phap kettua len tren chat mang a c tao hnh xac nh.

Phng phap ket tua


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Phng phap ket tua c dung nhieu trong cong nghiep. Co

nhieu cach ket tua:

1- Tam t chat mang bang dung dch cha loai muoi cua chat

xuc tac lam kho chuyen xuc tac sang dang hoat ong

Nhc iem: trong qua trnh lam kho, muoi chuyen dch ra be

mat ngoai mot phan be mat trong khong c phu chatxuc tac.

Phng phap ket tua


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2- Tam chat mang bang dung dch, sau o x ly hoa hoc.

3- Ket tua ong thi chat mang va chat xuc tac, tao vien va lam

kho.

4- Tron hai cau t dang kem nhao, tao hnh va lam kho.

Phng phap ket tua


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5- Phun chat xuc tac len be mat chat mang (phng phap nay thch

hp cho chat mang khong xop).

6- ien di ket tua, hay hap phu cac ket tua xuc tac t dung dch

long, hi len chat mang.

Phng phap ket tua


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Cac phng phap khac:

TachAl khoi hp kim 50%Al, 20% Ni bang dung dch thuxuc tac Ni

Tach loai cac chat khong co li cho xuc tac khoi at set

thien nhien xuc tac alumosilicat.

Ngng tu hi tren si thuy tinh (chat mang)

Hoat hoa be mat xuc tac


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La giai oan can thiet trong qua trnh ieu che xuc tac: tachchat b hap phu, ket tua v.v ra khoi be mat chat xuc tac(a lam bien oi tnh chat hoa hoc va ly hoc cua chat xuctac).

Co the tien hanh ngay trong qua trnh s dung.


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Xuc tac b au occo the t phuc hoi trong qua trnh lamviec, hay phuc hoi theo chu ky trong thiet b phan ng hay trongthiet b rieng.

Tranh xuc tac b ngo ocbang cach thay oi qui trnh kythuat e co li cho xuc tac.


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Phan loai xuc tac theo phng phap chuan b va ban chat hoa hoccua chat xuc tac


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ket tua

ket tua tren chat mang

tron c hoc cac cau t

nong chay

khoang thien nhien, zeolite...

Quy trnh ky thuat chung


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Giai oan 1: Thu nguyen lieu ran ban au: (Cac chat tham gia

vao thanh phan cua chat xuc tac cuoi cung + cac chat can

phai c loai bo)

Giai oan 2: Phan huy hp chat co cha cau t xuc tac (nhiet

phan hay phan huy) san pham.

Giai oan 3: Bien oi thanh phan cua chat xuc tac

Yeu cau ve nguyen lieu au

hS ong nhat


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thanh phan hoa hocxac nh co kch thctheo yeu cau o amcan thiet khong co chat oc

gia ca thap, v.v

S ong nhat

ve thanhphan hoa

hoc cua chat

xuc tac

Phng phap troncac thanh phanban au, ieu kien van chuyen, baoquannguyen lieu


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Thanh phan pha nguyen lieucau truc xop cua chat xuctac

Tap chatco t nguyen lieu au giam hoat tnh, o chonloc cua chat xuc tac.

Tap chat gia thanh.


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Ncdung e hoa tan, pha loang va ra cac chat trong quatrnh san xuat chat xuc tac

Vat lieu lam thiet btrong san xuat. Thiet b phai c lambang vat lieu khong an mon, khong tao vay oxyt, v.v

Cac qua trnh c ban trong san xuat chat xuc tac

C h h h kh l l


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Cac qua trnh thuy ong hoc: khuay tron, lang, loc.

Cac qua trnh nhiet: gia nhiet, lam lanh, bay hi, ngng tu hi.

Cac qua trnh khuech tan (chuyen chat): trch ly, hoa tan, kettinh, hap phu. lam kho

Cac qua trnh c hoc: tron cac phan t ran, nghien, phan

loai, nh hnh va cac qua trnh khac.

Cac qua trnh hoa hoc: ong the, d the.

Cac qua trnh hoa hoc

R i h l d h d h


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Rong rai nhat la s dung cac qua trnh d the, trong o cac

qua trnh hoa hocdien ra kem theo s khuech tanva chuyencac cau t t pha nay sang pha khac.

Kh - long: s hap phu hoat hoa va giai hap

Kh ran: s hap phu hoat hoa va giai hap

Long - ran va long long: s trch ly chon loc, tao chat mitrong phan trch ly.

nh hnh hat xuc tac va chat mang

k i h


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ket tu trong giot phun

ong vien nen, ep un

say phun paste

Cac chat ket dnh: bot talk, grafit, thuy tinh long, mot so axithu c va cac chat khac.

nh hnh hat xuc tac va chat mang


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Phng phap tao hnh anh hng en:

be mat rieng

cau truc xop cua khoi tiep xuc

o ben c cua hat

THU KHOI TIEP XUC TREN C S KET TUA


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ay la phng phap san xuat 80% cac chat xuc tac va chatmang xuc tac cong nghiep

u iem: gii han rong bien oi cau truc xop va be mattrong cua cac chat xuc tac va chat mang.

Nhc iem: tieu hao ang ke ca lng nguyen lieu lan lngnc.


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Cac giai oan quan trong theo phng phap ket tua

l h h h d l


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1- Hoa tanla qua trnh chuyen pha ran vao dang long trangthai phan tan phan t hoat tnh hoa hoc cua cac phan t

tang len tang toc o phan ng cua cac cau t vi nhau

Toc o cua qua trnh c xac nh bi lng chat hoa tan

trong mot n v thi gian.

Hoa tan

Hai yeu to anh hng trc tiep en s hoa tan la:


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Hai yeu to anh hng trc tiep en s hoa tan la:

Khuay tron giup lam tang s san bang cau t trong pha long, giam xuong lam cho qua trnh hoa tan tang len.

Nhiet o tang th he so khuech tan, s chuyen chat tang (doo nht giam); nhiet o tang cung lam cho o bao hoa tang

len. (Vi cac muoi Na2SO4, K2SO4, Na2CO3, Na3PO4, MgSO4thkhi nhiet o tang lam o hoa tan giam cho en khong).

Ket tuah h h h h k l


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2 - Ket tua:chuyen cac chat hoa tan thanh ket tua la tong cuahai qua trnh: tao mampha ran va s ln len cua cac mamtinh the, ket tua.

So lng mam tinh the xuat hien ban au phu thuoc: nong o

Ket tua


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So lng mam tinh the xuat hien ban au phu thuoc: nong o

dung dch ban au, nhiet o,pH,lc ion

S tach chat ran t dung dch dien ra vi s ln len cua tinhthe - qua trnh d the

Qua trnh ket tua tao he a phan tan, tai ket tinh (theo Kelvin -Thomson)

Tnh chat cua ket tua (o phan tan o xop hnh dang hat) c

Ket tua


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Tnh chat cua ket tua (o phan tan, o xop, hnh dang hat) c

cac nh bi cac yeu to:

nhiet o ket tinh

pH

thanh phan ban au cua dung dch

nong o cua dung dch

cng o khuay tron

th t o dung dch vao nhau

Ket tua


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Phng phap tien hanh ket tua anh hng nhieu en tnh chat cuasan pham:

Ket tua chu ky se cho san pham khong ong nhat ve thanhphan.

Ket tua lien tuc (suot thi gian nong o chat phan ng,pHmoitrng bao am khong oi) cho xuc tac kha ong nhat.

e thu khoi tiep xuc n cau t n pha co dang vi ong nhat

Ket tua


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e thu khoi tiep xuc n cau t, n pha co dang vi ong nhat

th yeu cau ieu kien tien hanh cang phc tap hn v o hoatan cua hp chat ket tua, thanh phan pha ran luc bat au vacuoi la khac nhau.

Loc


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3- Loc: Trong qua trnh loc cac cau t hoa tan thng hap phu tren be

mat ket tua.

Ra ket tua loc


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4- Ra ket tua locco the thc hien ngay trong qua trnh loc, nocho phep s dung lng ln dung dch ra e lam sach themket tua, ong thi cung tao ranh tren ket tua.

Say

5- Say:


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Say kho trc tiep, la phng phap cho phep tiep xuc khongngng cua ket tua vi chat lam kho.

Say tiep xuc la qua trnh say c truyen nhiet t tng chatlam kho en vat lieu do s truyen nhiet.

Phng phap ien: s dung dong ien cao tan hay nhiet Jun.


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Aluminosi l icat

dang vien, hnh cau, bot mn

Al2O3: 7 30%


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2 3

La xuc tac axit-baz, ng dung:cracking, alkyl hoa, polyme hoa, ongphan hoa

Trong qua trnh ieu che xay rangng tu gelAl2O3va SiO2do tao

lien ket SiOAl, trong o coca lien ket SiOSihay AlOAl


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S TNG HP ALUMINOSILICAT silicate, nc

Dd Na2O nSiO2

Al(OH)3, nc

Dd H2SO4

Dd Al2(SO4)3


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Sy kh

Nung

Sn bi v ht khng t tiu chun

Thnh phm xc tc

Giac

ng

t

Tch nc (co gel)

Hot ho htRa

Kt ta v nh hnh

Dd Na2O.nSiO2 Dd Al2(SO4)3

H thng thit b chun b thy tinh lng


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Dy chuyn h thng chun b dung dch Al2(SO4)3


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CAC CHAT XUC TAC TREN CHAT MANG

(PHNG PHAP TAM)

Cau t hoat ong nh tren chat mang co nhieu lo xop, trong o chat


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mang la vat lieu tr hoac t hoat ong. Tng tac vi chat mang co the lam thay oi kch thc gia cac

phan t trong xuc tac hay hoa tr trong lien ket do co lien quan entng tinh the.

Tuy thuoc vao loai thiet b phan ng, chat xuc tac tren chat mang

co the la vien vi hnh dang bat ky: cau, vi cau, hnh tru, vay...


(THEO PHNG PHAP TAM)

Tam cau t hoat ong xuc tac len chat mang xop bang dung dch


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g g p g g

cha cau t hoat ong xuc tac.

Cac chat hoat ong xuc tac c chon dang cac muoi nitrat,

cacbonat, acetat cua anion de b phan huy khi nung

Xuc tac kim loai thng thu dang hydroxyt tren chat mang, sau o

chuyen sang dang oxyt va kh (bang kh H2). en kim loai


(PHNG PHAP TAM)

Muoi kho tan: tam 2 giai oan:


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g

1. tam cau t th nhat

2. tam cau t th hai (la chat tao muoi kho tan vi cau tva tam giai oan 1)

ket tua c tao ra trc tiep tren chat mang xop.


(PHNG PHAP TAM)

Cac bc:


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Hut chan khong, tach kh t lo xop cua chat mang

X ly chat mang bang dung dch

Tach dung dch tha

Say va nung.


(PHNG PHAP TAM)


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Tam theo chu ky hay tam lien tuc.

Tam lien tuc cho san pham ong nhat hn ve thanh phan va hoattnh xuc tac.

Tam co the tien hanh mot lan hay nhieu lan (tuy ieu kien xem coat yeu cau chat hoat ong xuc tac cha).

Sau moi lan tam chuyen qua giai oan gia cong nhiet.


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So lan tam phu thuoc nhieu vao cau truc lo xop cua chat mang echuyen van chat en tan ben trong mao quan.

Mao quan nho, tang so lan tamlam bt cac mao quanco the

lam mat tac dung xuc tac phai tm so lan tam toi u.

ac tnh va qui trnh san xuat cac chatmang quan trong


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Chat mang vi be mat rieng nho (diatomit, amian, a bot)

Chat co be mat rieng ln (gamma oxid nhom, silicagel, at set,

alumosilicat)


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1, 2- Thiet b phan ng co gia nhiet va khuay tron; 3- Loc; 4- May ep; 5- May nghien truc - tron;

6- Tao vien; 7- Lam kho; 8- Lo nung

He thong san xuat silicagel vien nen)


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1, 13- Bnh cha dung dch; 2- Bm; 3- Thung cao v; 4- Ap ke; 5- Thung em; 6- Van chnh;7- He thong lanh; 8- Lu lng ke; 9- Mang dan chat xuc tac; 10- Cot nh hnh hat xuc

tac; 11- Bo phan phoi; 12- Dau hon hp

He thong san xuat silicagel dang vien cau

KHOI TIEP XUC TREN C S TRON C HOC CAC CAU T VAO NHAU

Cac qua trnh c ban:tron cac cau t vao nhau e co the tao dung dch


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ran, hp chat hoa hoc, he nhieu pha.Phng phap t:Tron huyen phu cac loai cau t vao nhau ket tualoc

saynh hnh.

Ham lng cac cau t trong xuc tac phu thuoc:

nong o trong dung dch

kha nang hap phu huyen phu o am con lai cua ket tua

u iem: o ong eu tot.

Nhc iem: ieu kien tien hanh nghiem ngatkho khan trong sx cong nghiep

KHOI TIEP XUC TREN C S TRON C HOC CAC CAU T VAO NHAU

Phng phap kho:tron cac cau t ran ong thi vi viec


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lam am hon hp tao ra (can cho viec tao hat).

- Nhc iem: kho thu c khoi cac cau t ong nhat

Cac chat xuc tac san xuat theo phng phap nong

chay

Cac giai oan:


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1. chuan b mang li vi thanh phan can thiet2. phan bo cac cau t

3. nh hnh hay lam nguoi hp kim

4. nghien en kch thc can thiet.

Chat xuc tac tren bo khung (Skeleton catalysts)

Cac chat xuc tac tren bo khung c dung trong cac qua trnh:


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hydro hoa ng, dau, furfurol, quinon a nhan, v.v

la thanh phan cua cac ien cc cua pin nhien lieu nhiet o thap.

Chat xuc tac tren bo khung (Skeleton catalysts)

1. Vat lieu e thu cac khoi tiep xuc tren bo khung la cac hp kim lng


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hay a cau t cua cac kim loai hoat ong xuc tac.

2. Cac thanh phan cua hp kim nay b tach loai ra khi x ly bang cac

dung dch cac chat ien ly manh, chng cat trong chan khong

3. Khi tach

kỹ thuật xúc tác - hui - nguyễn Ánh nga

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