Download pdf - Tong Hop Xuc Tac Tren Chat Mang

8/13/2019 Tong Hop Xuc Tac Tren Chat Mang

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Sn xut xc tctrn cht mang

ZeoliteSilicagelOxit

nhm

Bi thuyt trnh

Sn xut xc tc trn cht mang

Thc hin :

Nguyn Minh Kha MSSV: 60501215Phng Quc Tm MSSV: 60502475

Lp HC05KSTN

Hng dn: C Trn Mai Phng


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nhm

Sn xutxc tc trncht mang

Phngphp chung

Mt s chtmang quan

trng

SilicagelOxit

nhmZeolite


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nhm

Cho cau t hoat ong gan vao chat mang.

Chat mang la vat lieu tr, co nhieu lo xop va t hoat ong hoa

hoc.

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

co the co nhng hnh dang nh: cau, tru, vay

I AC TRNG CHUNG CUA PHNG PHAP


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nhm

ac trng chung cua phng phap

Thng ngi ta tam cau t xuc tac len chat mang bang dung dch

cha cau t o.

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

chuyen sang dang oxyt va kh en kim loai.


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CAC BC THC HIEN VIEC TAM HAT CHAT

MANG

Hut chan khong kh t lo xop cua chat mang.

X ly chat mang bang dung dch.

Tach dung dch tha.

Say va nung.


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Hut chan khong chat mang

Tang s ong nhat cua hat trong qua trnh tam

Tang nhanh qua trnh tam

V:

Thng trc khi tam trong cac mao quan b bao hoa mot lng kh de

tan vao dung dch tam

Km ham s tham qua cua dung dch tam


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Hut chan khong chat mang

Ky thuat chan khong co nhieu phc tap nen thng giai oan nay

c bo qua.

Mat khac, ap suat mao quan khi tam co the at en hang tram

atm, no de dang thay the khong kh trong mao quan.

Qua trnh thay the nay cang nhanh neu co gia nhiet.


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Tam lien tuc cho san pham ong nhat hn ve thanh phan hoat tnh xuc

tac.

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

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

ac biet mao quan nho, tam nhieu co the lam bt hoan toan cac mao

quan, lam mat tac dung xuc tac.

Theo chu k

Lin tc

Tm xctc


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nhm

Tam xuc tac

a so cac trng hp, thi gian tam co the xac nh theo pt Enstein:

r: quang ng i trung bnh cua cau t khuech tan (xem la ban ban knh

hat).

De: he so khuech tan.

= r2/(2De)


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nhm

II/ MOT SO CHAT MANG QUAN TRONG

Silicagel

Oxit nhom

Zeolite


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nhm

La chat trong suot hay hat m, co nhieu lo xop.

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Cau truc xop phu thuoc vao loai silicagel, co the dao ong khoang

20-60%.

Be mat rieng 200-800 m2/g.

ng knh lo xop khoang 3-10 nm.

ong vai tro nh la chat mang cua chat xuc tac hoat ong.

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Trong cong nghiep, cho hydroxit silicagel p vi H2SO4.

Quy trnh

Hydroxyt vo nh hnh cua silic (SiO2.n H2O)

S bien oi cua gel theo c che a ngng tu, tao cac phan t vi

kch thc keo dang cau.

nSi(OH)4SinO2n-m + (2n-m)H2O

keo gel ra sy

San xuat

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Ngoai ra, san xuat silicagel trong cong nghiep theo p:

Na2O.3SiO2+ H2SO43SiO2+ H2O + Na2SO4

Keo tao ra c ong ran, ra lam kho va nung.

Loai gel nh vay co cau truc xop ong nhat.

San xuat

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He thong san xuat

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O

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Ran chac

o xop kem (5-

25%)

Be mat rieng

nho (1m2/g).

Kem ben hn

Cau truc xop

(50-70%)

Be mat rieng

ln (120-150m2/g)

-Al2O3 - Al2O3

- Al2O3khong nhng la chat mang ma con la chat xuc tac cuanhieu phan ng.


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ac iem cua - Al2O3

Thanh phan (% khoi lng) : Na2O t 0,1-0,6%; SiO20,1-1,0%; Fe2O3

0,1-1,0%

ng knh cua hat khoang 3-4 nm.

Khoi lng rieng chat ong 0,6-0,9 g/m3.

o xop tong 0,4-0,7 cm3/g.

ng knh mao quan 3-4 nm.

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Ky thuat san xuat - Al2O3

Hau het eu da tren c s thu Al(OH)3bang cach tai ket tua at

set dang hydrat.

Ban chat qua trnh the hien theo phan ng sau:

2 Al(OH)3+ 3 H2SO4Al2(SO4)3+ 6 H2O

Al2(SO4)3+ 6 NaOH 2Al(OH)3+ 3Na2SO4

Sau o, ngi ta nung Al(OH)3thu c - Al2O3

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Chuyen hoa - Al2O3 -Al2O3

Thc hien nhiet o cao hn 11000C:

- Al2O3Al2O3 -Al2O3

Ta phai chuyen nh vay v trong mot so trng hp phai s dung xuc tac

trang thai tang soi, ao tron manh b mai mon nhanh va co theloi cuon ra khoi vung phan ng.

Can loai chat mang ac biet ran chac.

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SAN XUAT KHOI TIEP XUC

1/ Xuc tac GIAP-3

Thanh phan(%khoi lng): -Al2O3(93%), - Al2O3(1,8%), NiO

(5,1%)

The tch xop: ~35%

Be mat rieng: ~5 m2/g

Mat o chat ong: ~1,0 g/cm3

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2/ Khoi tiep xuc tang soi (FB)

Dung e oxy hoa SO2trong lp tang soi.

Chat xuc tac phai ac biet ran chac, v khi ao tron manh,

no thng b mai mon nhanh va loi cuon ra khoi vung phan

ng

V du: S ton that Vanadi khi lam viec che o tang soi trong 1thang >8-10% so vi trong lng ban au.

o ben c tang len ang ke khi s dung chat mang

aluminosilicat.

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Khoi tiep xuc tang soi (FB)

La dang hat hnh cau mau vang sam.

Thanh phan (% khoi lng): V2O5>= 7 ; K2O >=7 ; Al2O3~ 4-6 ; SiO2~

82-80

The tch xop ~ 50%Be mat rieng ~ 20 m2/g

o mai mon trong 1 thang


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Qua trnh thu chat xuc tac FB

1- Chuan b dung dch aluminosufat.

2- Thu chat mang hnh cau.

3- Lam kho, nung chat mang hnh cau.

4- Tam chat mang.5- Lam kho va xuc tac.

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Cng thc chung c dng sau:M2/nO.Al2O3.xSiO2.yH2O

trong n: ha tr ca ion kim loi Mx: t s mol SiO2/Al2O3y:s mol nc

x : xc nh tnh cht v cu trc ca zeolite

Zeolite l cc Aluminosilicate c cu trc tinh th h theokhng gian 3 chiu



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1. Cu trc zeolit :

Z

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Gi tr nht trong s xc tc zeolite l cc zeoliteA,X,Y v mt s khc .

Zeolite A c x 2;X c x = 2,2-3

Y c x = 3,1-5,0

Zeolite tng hp thu c thng l zeolite -Na



nhm

B khung ca zeolite cu trc vi hng trm khoangtng i ln, thng vi nhau qua ca s kchthc nh V d:Trong 1 gam zeolite c n

3x1020

khoang.Z

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Zeolite A Zeolite X,Y


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2.c im

-Zeolit bn nhit

-bn trong quan h tip xc vi cht c, nh cc ionsulfua , cc hp cht cha nito

-khng gy n mn thit b

-b mt pht trin (800 m2/g)

-kh nng trao i ion cao, bn c



nhm

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Trong mi loi zeolite c thnh phn, cu trc, bn

cht cation, kiu phn b cation kh ng nht

C cu trc xp ( th tch xp chim khong 50%V)

B mt tip xc pha ln

D dng to cc trung tm acid base khc nhau



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Z

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Cc l xp


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Hp ph c tnh chn lc rt cao

D dng trao i ion

Xc tc c hot tnh v chn lc cao



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Z

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3. ng dng ca zeolite

Ngoi ra zeolite cn l cht mang to ra nhiu loi xc tc khc : xc tcbase, oxi ha kh


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Mt phn t phn ng trn zeolite phi thc hincc bc sau: Khuch tn n b mt ca zeolit

i vo mao qun qua cc ca s v khuchtn n trung tm hot ng Hp ph vo bn trong mao qun trn trungtm hot ng v hnh thnh hp cht trung gian

ca phn ng Thc hin phn ng to sn phm Kh hp ph v khuch tn sn phm rangoi mao qun

O i


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4.Tng hp zeolite

-Cc zeolite tng hp c th thu c bng phng

php tng hp thy nhit dng cc tinh th vi kch

thc c micromet

-Vic tng hp cc zeolite dng Na+to ra kt ta

alumosilicat ca baz v cui cng to kt ta.



nhm

Z

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O it


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Sn xut zeolite dng vin



nhm

Z

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Dd lmvic

Kt tahydro

aluminosilicat

Kt tinhhydrogeltrong mt

kim

ra

nh hnh

x l nhit

O it


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nhm

Z

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Nguyn liu

silicat

Al(OH)3 NaOH

O it


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t nng dd lmvic

NaOH si

Al(OH)3

H2O

autoclave

silicat

H2O

Hi qu nhit

O it


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S O it


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Nhc im :

-Vic thm cht kt dnh lm xu i c trng

ng hc ca zeolite

-V vy ngi ta mi tm kim k thut to vin

zeolite khng c cht kt dnh.



nhm

Z

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S t t Oxit


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Sn xut zeolite dng vin khng cha cht kt dnh



nhm

Z

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S t t Oxit


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4.a xc tc vo cht mang zeoliteCc phng php s dng :



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trao i ion

tm

hp ph t pha kh hay a vo tkhu tng hp zeolite

hp ph hi kim loi

S t t Oxit


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Phng php x l zeolite:

3 phng php



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Z

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eTrao iion Tmzeolite Tnghp

S t t Oxit


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Trao i ion

Mc ch:

-thay th cc ion Na+ bi cc ion nguyn tkhc hay H+

-Bng phng php ny c th a vocu trc zeolite cc kim loi nh Ni, Pt



nhm

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S t t Oxit


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Nhn xt:

-S phn b tt nht kim loi c th t c

trong trng hp : trc giai on kh phi khht nc trong zeolite.

-Trong qu trnh kh cc mu ngi ta nhnthy c s di chuyn kim loi t th tch ca

tinh th zeolite n b mt bn trong ca chngv to ra cc kim loi dng khi. Dc theokhoang s di chuyn ca kim loi trong zeolitec sp xp theo dy sau: Ag>Pb>Cu>Ni > Pt



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Sn xut xc tc Oxit


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Tm zeolite

c thc hin bng mt s dung dch hu c hay

v c cha hp cht cc kim loi m c th tch

thnh kim loi khi x l nhit nhit thp hn

nhit bn ca tinh th do vy thng s dng

cacbonat v hydrocacbonat ca Fe, Co, Ni, Cr....



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Sn xut xc tc Oxit


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Tng hp

Mc ch:a cu t hot ng vo xc tc t lctng hp zeolite

Phm vi s dng:

Khi c kh nng a cc cu t xc tchot ng vo mng tinh th.

u im:- C th thu cht xc tc sau phn ng- Xc tc c chn lc cao



nhm

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Sn xut xc tc Oxit


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Ngun ti liu :

Bi ging k thut xc tc - Mai Hu Khimwww.Wikipedia.comwww.china-silicagel.net

www.sciences.com
http://www.china-silicagel.net/http://www.china-silicagel.net/http://www.china-silicagel.net/http://www.china-silicagel.net/