Công Nghệ Chế Biến Khí -CHƯƠNG 5. CHẾ BIẾN KHÍ

8/11/2019 Cng Ngh Ch Bin Kh -CHNG 5. CH BIN KH

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CNG NGH

CH BIN KH

Trng i hc Cng nghip

TS. Nguyn Mnh Hun


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Slug

catcher: ng di gy p sut thptrong ng dn kh khin nhng dngphun condensat tch t li


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Kh thien nhien va kh ong hanh ng dung theo hai hng:

- Lam nhien lieu (kh kho)

- Nguyen lieu hoa hoc. Kh beo cha t 50 en 100% C3+ c che bien khac nhau.

Trong che bien kh trc tienthu hoi xang thien nhien (qua trnh loai xang).

Sau khi loai xang: kh (metan, etan, propan va butan) phan tach e thu c cac

H/C rieng le.

Trong qua trnh on nh: thu LPG.


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-Phng phap nen: nen, sau o lam lanh H/C nang ngng tu, phan rieng.

Phng phap: re, nhngkhong thu hoi hoan toan H/C nang.

ng dung ket hp vi cac phng phap khac: nen, tach cac H/C nang, kh tiep tuc c phan tach

(chng cat nhiet o thap hoac ngng tu nhiet o thap).

-Ngng tu nhiet o thap: kh nen, lam lanh, ngng tu mot phan cac H/C nang nhat, vao thap phan

rieng tach kh. Kh kho ong dan kh,

Phan ngng tu thap chng cat, thu kh va xang thien nhien.

-Chng cat nhiet o thap: nen, lam lanh, vao thap chng cat thu kh (C1 va C2)vao ong dan kh, va

H/C nang (kh xang).

Nhiet o tren cua thap chng cat luon am, con phan di nung nong. thu hoi hoan toan H/C

nang.


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I. CHE BIEN KH BANG PHNG PHAP NGNG TU

I.1. Khai niem chung

Ngng tu kh la qua trnhlam lanh ang ap en nhiet o xuat hien pha long.

n chat: iem ti han ( TC va P

C ) T>T

C, P >P

C :trang thai mot pha,khong the chuyen sang trang thai

hai pha

Kh ong hanh va kh thien nhien lahon hp a cau t covung ti han

Nhiet o va ap suat ti han ngng tu cua he a cau t : T va P cc ai co the ton tai hai pha.

+ Trong giam o pha covung hon hp the hien mnh nh n chat nhng hon hpchuyen pha trongmot vung nhiet o.

+ Qua trnh nen hoac n ang nhiet tng t nh cac n chat nhng pha long hnh thanh hoac bay

trongmot vung P

+Vung thoai hoa, qua trnh ngng tu ngc.


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Xet qua trnh ngng tu kh ngoai vung ti han va can ti han.

+ Kh co nhiet o ngng tu khac nhau lam lanh thanh phan co Tngng tu cao nhat ap suat rieng phan

cua no se ngng tu trc tien.

+ Neu cac thanh phan ton tai can bang: trc tien thanh phan Tngng tu

cao nhat se u tien ngng tu trc.

ac tnh quan trong cua kh H/C: hoa tan trong H/C long ca chat co nhiet o Thon hp > TC cung chuyen

sang pha long.

Th du: Hon hp: 10% mol CH4 va 90% mol C3H8 ngng tu hoan toan T= 10oC, P= 2,0 MPa. CH4 (TC = -

82o

C) se chuyen sang the long 10o

C neu co C3H8.Hoa tan kh va ngng tu kh - toa nhiet.

T giam lng chat long tang va chat long giau cac chat de bay hi hn, pha kh cung giau cac chat d

hi.

Tiep tuc lam lanh, qua trnh tiep tuc en ngng tu hoan toan.


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Hnh V.1. S phu thuoc mc ngng tu vao nhiet o va ap suat


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S o nguyen tac che bien kh bang phng phap NTNT gom:nen en P; lam kho; lam lanh en T etao hai pha; tach; kh kho i s dung, pha long i loai etan hoac metan (C3+ , C2).

Hnh V.2. S o nguyen tac che bien kh bang phng phap nhiet o thap 1- May nen kh nguyen lieu; 2- cum lam kho kh; 3- cum lam lanh; 4- thap tach; 5- thap deetan hoa (hoac demeta

I- Kh nguyen lieu ap suat thap; II- kh nguyen lieu ap suat cao; III- kh nguyen lieu a lam kho; IV- hon hp hai pha hi

lanh; V- kh kho; VI- phan ngng tu; VII- phan oan hydrocarbon; VIII- kh hydrocarbon t thap deetan hoa.


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Phan loai s o ngng tu nhiet o thap

S o cong nghe che bien NTNT c phan loai:

- Theo so giai oan tach;

- Theo dang chat lam lanh;

- Theo san pham chnh. Theo so lan tach: mot, hai va ba giai oan.

Theo dang nguon lanh:

- Chu trnh lam lanh ngoai;

- Chu trnh lam lanh noi;

- Chu trnh lam lanh hon hp (ngoai va noi).

Dang chat lam lanh:

-Chat lam lanh n chat :etan, etylen, propan...

-Chat lam lanh a phan:hon hp C1, C2, C3, C4...

Theo dang san pham chnh: s o san suat C2+ va C3+.


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Chat lam lanh ngoai hon hp :

Trong s o vi chat lam lanh ngoai hon hp: chat lam lanh tuan hoan trong he thong kn (may ne

kh- may lanh - bay hi - may nen kh) chu trnh lanh ngoai ,

S dung chat lam lanh hon hp cho T thap hn nhieu

cao hn.

Chat lam lanh hon hp co the chia thanh 2 nhom:

- Thanh phan co nh c chuan b san ngoai:

S o khong khac vi s o chu trnh lanh propan ngoai.

- Nhan trc tiep trong s o, thanh phan thay oi

S o se phc tap hn.

h h b


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Chu trnh lam lanh noi : Chia thanh cac nhom: - tiet lu dong long - gian n kh .

Co the ng dung tat ca nguon lanh la tiet lu cac dong long, nhng khong kinh te va ng dungphc tap.

ng dung lam lanh noi: - Kh co o beo thap (C3+ < 70 75 g/m

3) va thap. - Kh ong hanh: ket hp lam lanh propan ngoai va lam lanh noi:Trong giai oan I: lam lanh ti -30oC nh lam lanh ngoai,

Trong giai oan II: nhiet o thap hn - tiet lu dong long- Lam lanh hon hp noi va ngoai ng dung cho kh co o beo trung bnh (C3+ 300 g/m

3).Kh co ham lng C3+ > 70 75 g/m

3 va can co cao ng dung lam lanh hon hp.

h h bi


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I.2. S o cong nghe che bien kh bang phng phap ngng tu nhiet o thap (NTNT).

1. Ngng tu lam lanh ngoai

1.1. S o ngng tumot giai oan, lam lanhpropan ngoai, san phamC3+

ac iem:

- S o co ien, c ng dung rong rai.

- C s e phat trien nhng s o hien ai.

- S o co: 1 nguon lanh ngoai - propan va 1 thiet b phan rieng.

h h bi


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Hnh V.3. S o NTNT mot giai oan 1, 7 - Thap tach; 2- may nen; 3 - may lanh khong kh; 4, 5 - trao oi nhi

6,10 - thap bay hi propan; 8 - thap deetan; 9 - be cha;11-noi soi lai.

I - kh nguyen lieu; II - kh kho; III - phan oan hydrocarbon (C3+).

I.2. S o cong nghe che bien kh bang

phng phap ngng tu nhiet o thap (NTNT).

1. Ngng tu lam lanh ngoai

1.1. S o ngng tumot giai oan, lam

lanhpropan ngoai, san phamC3+

ac iem:

- S o co ien, c ng dung rong rai.

- C s e phat trien nhng s o hien

ai.

- S o co: 1 nguon lanh ngoai - propan va

1 thiet b phan rieng.

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Deetan hoa la cum c ban:- Chat lng san pham va hieu qua kinh te phu thuoc vao hieu qua lam viec cua no.

+ Tang [C3H8] trong san pham nh tang mat mat san pham+ [C

2H

6]> 2 3% k.l. th C

3+ khong hp qui cach

- Deetan hoa la thap chng cat:

+ 10 12 mam ly thuyet, sau nay 30 mam supap,+ P = 3,0 3,5 MPa.+ La chon ap suat da vao:

o P > 4,0MPa khong oi hoi chi ph them nang lng duy tr P trong thap deetan,o Vi ap suat nh vay chat lam lanh propan ap ng che o nhiet o nh.o P cao lam xau ieu kien phan tach pha.o 3,5 MPa = 0,8 gia tr PC san pham ay

Tnh = 0 -30oC, Tay = 90 120

oC.

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Deetan hoa

Lo gia nhiet va thapdeethan hoa nha

may Dinh Co

San pham cua thap deetan hoa:

-nh: CH4 (20 70% t.t), C2H6 (30 75%t.t.) va C3H8 < 5%t.t

-ay: C3+ propan, butan, pentan va kh xang (C5+) hoac kh dan dung.

C gh h bi kh


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Hnh V.5. S o NTNT vi chu trnh gom cacchat lam lanh hon hp. 1,4 - May nen kh; 2,5 - may lanh khong kh, 3,6,9 - trao oi nhiet; 7 - thiet b lam l

bang chat lam lanh hon hp; 8,10 - thap phan rieng; 11- thap deetan; 12 - be ch

13,14 - van tiet lu. I - Kh nguyen lieu; II - kh kho; III C3+.

1.2. S o NTNTmot giai oan, chat lam lanh hon

hp, nhan C3+

ac iem:

- Chat lam lanh nhan c trc tiep trong s o- Cong suat kh1 ty m3/nam,

C3 = 84%.

-Tang phan t lng chat lam lanhcong suat lam

lanh cua no tang Khoi lng chat lam lanh va

nang lng chi cho viec nen giam.-Thanh phan chat lam lanh co the la chon sao cho

viec ng dung no kinh te hn so vi s dung chu

trnh propan.

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1.3. S o NTNTmot giai oan, lam lanhpropan va etan, nhanC2+

Hnh V.6. S o NTNT mot giai oan vi cac chu trnh lanhpropan ngoai va etan enhan c C2+.

1,4,10 - Thap tach; 2 - may nen; 3 - may lanh khong kh; 5 - cum lam kho; 6,8- trao onhiet; 7,12,15 - lam lanh bang propan; 9 - lam lanh bang etan; 11 - thap demetan; 13, 16 -

cha; 14 - thap deetan.

I- Kh nguyen lieu; II - kh kho; III - phan oan hydrocarbon; IV - etan thng pham.

ac iem:

- co 2 nguon lanh rieng re tren mot giai

oan:propan va etan.

- Lam lanh kh trong may lanh khong kh 3,

trao oi nhiet 6, lam lanh propan 7, trao oi

nhiet 8 va thiet b lam lanh etan 9 ma

khong tach pha long etan hoa tan nhieu

hn trong H/C long tang thu hoi C2.

- Co Thap demetan: loai toan bo metan ra

khoi phan oan H/C nang va tranh mat

mat etan.

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Thap demetan hoa:

P = 3,5 4,0 MPa,T13 = -60 -90

oC, xac nh C2 : T13 cang thap C2 cang cao. Tdi = 20 60

oC,20 25 mam supap.

- Thap demetan lam viec can thoa man: [C2] trong san pham nh < 5% k.l. ;[C1] < 2%k.l.Thap deetan: P, Tdi nh trong thap demetan,

Ttren cao hn nhieu (0 10oC) do [C1] trong nguyen lieu va san pham tren cua thap etan thap (< 2%

k.l.).San pham nh cua thap etan: thng pha hi, nhng trong mot so trng hp no c hoa lon- Thap deetan can ap ng o sach san pham:

[C3] trong san pham nh < 2% k.l.;[C2] trong san pham ay < 2%k.l

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Hnh V.7. S o NTNT hai giai oan e nhan c C2+ vi chu trnhlam lanh propan va etan. 1 - Thap tach; 2 - thap lam kho; 3 - bo loc bui; 4- he trao oi nhiet va lam lanh bang propan; 5,7- thap phan rieng nhiet o thapthong trao oi nhiet va lam lanh bang etylen; 8,15 - be cha; 9- thiet b lam lanh bang etylen;10 - thap demetan; 11,16 - noi soi lai; 12 - be

cha trung gian;13 - thap deetan; 14 - thiet b lam lanh bang propan; 17 - bo phan lam sach CO2; 18 - thiet b lam lanh bang propan.

I- Kh nguyen lieu; II- metan; III- etan; IV- C3+

1.4. S o NTNT2 giai oan, lam lanhpropan va

etan, nhanC2+

ac iem:

-Chu trnh lam lanh propan-etan hoac propan - etylen.

- Trong giai oan I: lam lanh bang C3, II:

etylen hoac etan.

ng dung: thu hoi sau C3 (> 80%), hoace

tach C2.

Cong suat: 4,25 trieu m3 kh thien nhien/ngay

(~1,5 ty m3/nam).

Thu hi: C2 = 85%, C3 = 99% va C4+ =

100%

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Cum cong nghe ien hnh che bien kh thien nhien, kh ong hanh e thu c etan.

Khong co s khac nhau gia lam lanh propan-etylen va propan-etan, nhng propan-etylen cho phep

nhan c T thap hn

(nhiet o soi cua etan la-88,65oC, cua etylen la-103,71oC), u the chu trnh propan-etan: nhan trc

tiep trong nha may

Qua trnh ngng tu nhieu giai oan oi hoi au t cao hn.

+ Thu hoi C3+ : 1 giai oan.

+ Mc thu hoi C3+ hoac C2+ cao: 2 va 3 giai oan

hoac s dung lam lanh noi tiep, hoac lam lanh noi hoac hon hp.

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2. Ngng tu lam lanh trong (noi)

Che bien kh vi [C3+] < 70 75 g/m3 : NTNT vi nguon lanh duy nhat lathiet b gian n turbin

thu hoi sau: C2, C3 va C4+

S o tieu bieu:

- nen kh nguyen lieu;

- lam kho kh;

- trao oi nhiet ;

- phan rieng ap suat cao;

- giam ap turbin + phan rieng ap suat thap;

- demetan va deetan hoa;

- nen kh kho e a no vao ong dan chnh.

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2.1. S o nguyen tac NTNT vi thiet b giam ap turbin eche bien kh thien nhien.

Hnh V.8. S o cong nghe NTNT vi thiet bgiam ap turbin.1,3,5- Thap phan rieng; 2- trao oi nhiet hoan nguyen; 4- thiet b giam ap turbin; 6-

may nen chat lam lanh giam ap turbin. I- Kh nguyen lieu; II - kh kho; III- condensat.

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2.2. S o NTNThai giai oan,lam lanhgian n turbin va tietlu cac dong long , e nhancC3+

- Cong suat 3,7 trieu

m3

/ngay.- C3 = 85% va 100% H/Cnang.

ac iem: lng nhiet lanhdo trao oi nhiet vi kh loaixang va tiet lu condensat cung

cap.Hnh V.9. S o NTNT hai giai oan e nhan c C3+, lam lanh banggiann turbin va tiet lu cac dong long. 1,9 - Thap phan rieng; 2,3,4 - trao oi nhiet; 5 - thap tach ba pha; 6 - giamva may nen; 7 - thiet b hoan nguyen metanol; 8 - thap phong hoa; 10 - tdeetan hoa. I- Kh nguyen lieu; II- kh kho; III- C

3+; IV- metanol; V- condensat.

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3. Cac s o cong nghe NTNT vi chu trnh lam lanh hon hp 3.1. S o NTNTmot giai oan, chu trnh lanh hon hp, nhan C3+

Hnh V.10. S o NTNT mot giai oan e nhan c C3+ vi chu trnhlam lanh hon hp- propan ngoai va tietlu cac dong chat long. 1,3 - May lanh khong kh; 2 - may nen; 4,6,7,9 - trao oi nhiet; 5,8 - thiet b lam lanh bang propan; 10 - thiettiet lu; 11- thap tach nhiet o thap; 12 - thap deetan hoa; 13 - noi soi lai. I- Kh nguyen lieu; II- kh kho; III- phan oan H/C.

ac iem:lng nhiet lanh coc nhtiet lu condensat - So vi he khong co tiet lu th

s o naykinh te hn:e san xuat 1 kmol C3+ can5,65m3 nhien lieu thay v6,23 m3 theohe thong thng.

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3.2. S o thiet b NTNThai giaioan, lam lanh hon hp (propan ngoaiva tiet lu dong long), san xuatC3+

ac iem: C3 cao. - Lam lanh giai oan I: propan

ngoai,- Giai oan II - tiet lu condensat

t thap tach cua giai oan II va motphan t thap tach giai oan I.

Hnh V.11. S o NTNT hai giai oan e san xuatC3+ vi chu trnhlam lanh hon hp - propan ngoava tiet lu cac dong long. 1,12 - May nen; 2,13 - may lanh khong kh; 3,4,7,8,9,11 - trao oi nhiet; 5,15 - thiet b lam lapropan;6,10- cac thap tach nhiet o thap giai oan I va II; 14 - thap deetan; 16-be cha; 17 - may bhoi lu cho thap 17; 18 - noi soi lai cua thap deetan; 19,20 - tiet lu.

I- Kh nguyen lieu; II- kh kho; III- phan oan hydrocarbon.

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3.3. S o NTNT hai giai oan vi chutrnh lam lanh hon hp (propan ngoai,tiet lu dong long va giam ap turbin ),san xuatC3+

Che bien kh ong hanh co [C3+] =300g/m3 va C3 = 90%

ac iem: giam ap c dung thaycho chu trnh lanh etan (etylen).

Hnh V.12. S o NTNT hai giai oan vi chu trnh lam lanh hon hp - propan ngoaiva lam lanh noi e thu hoi C3+.

1,3,5 Thiet b lam lanh bang propan; 2, 4, 9, 14 - trao oi nhiet; 6, 8- lam lanh khongkh; 7,12 - may nen kh; 10, 11- thap phan rieng; 13- thiet b giam ap turbin; 15- thiet

b tiet lu; 16- thap deetan hoa; 17- noi soi lai. I- Kh nguyen lieu; II - kh kho; III- phan oan hydrocarbon (C3+)

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3.4. S o NTNTba giai oan vichutrnh lam lanh hon hp (propan ngoai,tiet lu dong long va giam ap turbin ),thu hoiC2+

C2 = 50 70%, C3 = 95%.ac iem:

- khong co lam lanh bang nc.- Dien tch nho hn 2 lan so vi

nha may hap thu nhiet o thap.

- Giam ap thay cho chu trnh lanhetan (hoac etylen). Hnh. V.13. S o NTNT ba giai oan e thu hoi C2+, s dung chu trnh lam lanhhp (propan ngoai, tiet lu dong long va giam ap turbin ) 1- Thap tach - loc; 2 - thap hap phu; 3 - may lanh propan; 4,7,10 - thap phan rientrao oi nhiet; 8- thap phong hoa; 9- thiet b giam ap turbin; 11 - thap demetan; 12soi lai; 13 - may nen kh lam viec bang nang lng t thiet b giam ap turbin may nen kh; 15 - may lam lanh khong kh.

I- Kh nguyen lieu; II- phan oan hydrocarbon C2+; III- kh kho.

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ng dung cac cong nghe NTNT vi chu trnh lam lanh ngoai va noi

Giam ap turbin ng dung tot: vungT= -45 -75oC.

[C3+] > 70 75 g/m3, C3+ cao lng nhiet lanh do giam Pkhong u lam lanh them.

ac iem cua thiet b giam ap suat turbin:

Mc giam ap cho phep, 2 3,5

Giam nhiet o,oC 26 48

o hoa long kh, % 5 20

o nen kh do nang lng tao ra t giam P 1,3 1,5

P tai ca vao thiet b giam P turbin, MPa 1,103 9,240

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II. CHE BIEN KH BANG PHNG PHAP HAP THU

II. 1. Ban chat vat ly va cac qui luat c ban

Ban chat cua qua trnh: khuech tan vat chat chuyen t pha nay sang pha khac khi cochenh lech nong

o cho en khi at c trang thai can bang

ong lc cua khuech tan: chenh lech ap suat rieng phan cua cac nguyen to trong cac pha kh va long.

e thuan tien, ong lc khong bieu dien thong qua ap suat rieng phan, ma quanong o cua cac nguyen

to .

Hap thu va giai hap tien hanh trong cac thiet b hap thu va chng cat dang mam va dang em.

Mot so khai niem va cac phng trnh dung cho tnh toan qua trnh hap thu hon hp a cau t trong ie

kienat ti can bang cua cac dong tng tac trong moi giai oan phan chia.

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Hnh V.14. H thng cc dng vt cht trong hp th. I - kh nguyn liu; I I - cht hp th bo ha; I I I - kh kh

I V - cht hp th sch.

Cac ky hieu trong hnh:Yij - ham lng cau t i trongpha kh ra khoi mam j, mol/molkh nguyen lieu;Xij - ham lng cau t i trongpha long ri xuong t mam j,mol/mol chat hap thu hoan nguyen;

Xo - ham lngH/C thu hoi con lan trong chat hap thu hoannguyen, mol/mol chat hap thu hoan nguyen;Kij- he so can bang pha cua cau t i tren mam j;Lo - lu lngchat hap phu tuan hoan, mol/gi;Lj- lu lngpha long ri khoi mam j, mol/gi;Ln- lu lngpha long ri khoi thap, mol/gi;Gj - lu lngpha hi ri khoi mam j, mol/gi;Gn+1 - lu lngkh nguyen lieu i vao thap hap phu, mol/gi.G1- khoi lngkh kho, mol/gi;

- the tch chathap thu hoan nguyen c a vao thaphap thu, l/gi;

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A = (V.3)

Trong o:

K - he so can bang cuachat can thu hoi nhiet o hap thu trung bnh;

L'o - the tch chat hap thu hoan nguyen c a vao thap hap thu, l/gi;

- trong lng rieng cua chat hap thu hoan nguyen, kg/l;

M - phan t lng cua chat hap thu hoan nguyen.

Khi G1 = 1 mol/gi th phng trnh (V.3) tr thanh:

A =

35

Cng g c b kh

CHNG5. CH BIN KH

1

4,22.' KMG

Lo

KM

Lo 4,22.'

- he so thu hoi hoac he so hap thucua mot chat (khoi lng chat c thu hoi/khoi lng cua chat nay cha trong kh

nguyen lieu):

Phng trnh Cremser Braun

11

1

n

n

A

A A

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Hnh V.15. Gian o Cremser

Phng trnh Cremser Braun

11

1

n

n

A

A A

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II.2. S o cong nghe nguyen tac che bien kh bang phng phap hap thu

S o hap thu gom co: thiet b tach, nen va lam kho kh, thap hap thu, thap demetan hoac deetan v

thap giai hap.

+ Trong thap demetan va deetan giai hap cac H/C chnh (C2+ hoac C3+) t chat hap hap thu bao hoa

S o cong nghe nguyen tac cua qua trnh hap thu thu hoi C3+ (s o hap phu dau (HTD).

S o ac trng cho cac s o hap thu hien ai: Kha nang hap thu do kh nguyen lieu va chat ha

hoan nguyen lam lanh trongmay lanh khong kh va nc en25 35oC tao ra.

Trong cac s o tien tien kh va chat hap thu c lam lanh nh chu trnh lam lanh tng ng en nhiet

o -30 -45oC

C3 = 40 50%; C4 = 85 90%, xang = 95 100%.

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Hnh V.16. S o he thong hap thu dau 1- Thap hap thu; 2- thap hap thu- bay hi; 3- thap giai hap; 4, 5- trao oi nhiet thu hoi; 6, 7- lam lanh khong

lam lanh khong kh hoac nc; 9- bon cha; 10- noi soi lai. I- Kh nguyen lieu; II- kh kho; III- chat hap thu bao hoa;IV- chat hap thu bao hoa loai etan;V- kh kho; VI-

oan hydrocarbon; VII- chat hap thu hoan nguyen

Trong cac s o nay che o nhiet cua HTBH

c qui nh chat che bi nhiet o cua thap

hap thu va thap giai hap:

- T cap do T san pham ay cua thap hap thu

qui nh;

Tdi do lng chat hap thu tuan hoan va Tdi

cua thap giai hap qui nh.

Khong cho phep toi u hoa che o cong

nghe cua HTBH.

- Che o nhiet khong ieu chnh theo chieu

cao.

Vi s o cng nhac nh vayboi so hoi lu

trong HTBHcao vathat thoat propan cung kh kho

cua thap HTBHln, ong thi cung co nhng

kho khan trong ieu hanh thap giai hap do ham

lng etan trong san pham HTBHcao.

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CHNG5. CH BIN KH

Cai tien:

-S dung he thong lam lanh chuyen dung ben canh nc (khong kh)

-He s o co hai phan :

+ NTNT: co loai xang trc kh nguyen lieu

+ HTNT: co C3 t kh ong hanh cao:

HTNT : C3 = 90-95% ch can T= -30 -38oC,

NTNT can lam lanh en -80 en -85oC.

-S dung chat hap thu nhe ( M= 80-140), chi ph rieng< 1-1,5 l/m3 tangmc thu hoi san pham va giam chi ph rieng cho che bien kh 25-50%.

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CHNG5. CH BIN KH

II.3. Thong so lam viec va cac phng phap hoan thien cac bo phan chnh cua s o hap thu nhiet o thap

Cac thong so cong nghe co anh hng:

P, T,

thanh phan nguyen lieu va chat lng san pham,

so mam trong thap hap thu va thiet b chng cat,

tnh chat hoa ly cuachat hap thu

Cac nh hng chnh e hoan thien qua trnh HTNT:

-giam Tnguyen lieu vao thap hap thu;

-tang P trong he HTNT va hap thu kh;-bao hoa chat hap thu tuan hoan bang etan va (hoac) metan bang cach tron vi kh kho cua thap hap thu va (hoa

thap hap thu-bay hi ;

-s dung chat hap thuphan t lng thap;

-ieu chnh lay nhiet theo chieu cao...

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CHNG5. CH BIN KH

1)Cum hap thu.

ng dung lam lanh propan: T =(-30) (-40)oC C2 = 40-50%, C3 = 95% va xang ~ 100% vi cac ch so kinh te-ky thuat cao.Ap suat: 3 7 MPa.

- Ap suat cho che bien kh gay thap hn cho che bien kh beo.

- Nga cho che bien kh ong hanh: P < 4 MPa,che bien kh thien nhien P < 5,5 MPa.

-Khi la chon P:+ P e at toi u;+ P trong ong dan kh sach

+ Nga P ban au trong ong dan chnh la 5,4 7,4 MPa co the gi P

Nhng tang P tang lng H/C nhe theo ra cung C3+ lng kh trong thap hap thu-bay hi tang tang that thoat C3+ Giam T va tang P cho phep s dung chat hap thuphan t thap lng (M=80-120) chi ph chat hap

thu thap hn.

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CHNG5. CH BIN KH

Hnh V.17.a) Thay oi ham lng cac cau t thu hoi trong thap hap thu doc theo chieu cao thiet b hap thu I- kh nguyen lieu; II- kh kho; V- chat hap thu tuan hoan ;V- chat hap thu bao hoa. b) Thay oi nhiet o theo chieu cao thiet b hap thu. 1- kh; 2-chat hap thu

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Toa nhiet ln nhat phan tren va di cua thap hap thu:

-Pha tren hap thu khoi lng c ban metan va etan,

-Phan di C4+

e tieu chuan hoa che o nhiet can lay nhiet theo chieu cao:

-lam lanh trung gian chat hap thu bao hoa trong trao oi nhiet( hap thu- lam lanh - hap thu ): nguyen to cang nhe

th v tr lay nhiet toi u cang gan en gia thap

-lam lanh chat hap thu bao hoa trongthiet b trao oi nhiet at trong long thiet b

-bao hoa chat hap thu hoan nguyen bang H/C nhe ket hp vilay nhiet trc khi a chat hap thu vao thiet b.

Trong nhng nam sau: khong dung phng an hap thu- lam lanh - hap thu v he so truyen nhiet thap va be

trao oi nhiet ln. s dung bo phan bao hoa trc chat hap thu

Phng an nay n gian, co o tin cay cao va co hieu qua.

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CHNG5. CH BIN KH 3 he thong c ban dung cho bao hoa trc chat hap thu.

-Phng an th nhat- chat hap thu hoan nguyen tron vi kh kho cua thap hap thu-bay hi. Do tiep xuc cua cac dong, chahap thu c bao hoa H/C nhe va ong thi c lay nhiet ra

Hnh V.18. S o nguyen tac bo phan hap thu vi viec bao hoa trc chat hap thu hoan nguyen bang kh kho cua thap thap hap thu bay hi ( phng an I) 1,5- thiet b lam lanh bang propan; 2,6- thap tach; 3- thap hap thu; 4- thap hap thu bay hi (HTBH);7- noi soi lai I- kh nguyen lieu; II, III, V - kh kho sau khi bao hoa trc chat hap thu hoan nguyen; IV- chat hap thu hoan nguyen sau khi c bao hoa trc; VI- cha

nguyen; VII- chat hap thu bao hoa deetan; VIII- chat tai nhiet.

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CHNG5. CH BIN KH

- Phng an hai( hnh V.19) - chat hap thu bao hoa hai lan

Hnh V.19. S o nguyen tac bo phan hap thu vi viec bao hoa trcchat hap thu hoan nguyen bang kh kho cua thap hap thu va thhap thu bay hi ( phng an II) 1,5, 7 - thiet b lam lanh bang propan; 2,6,8 - thap tach; 3- thap hap thu; 4- thap hap thu bay hi (HTBH); 9- noi soi lai I- kh nguyen lieu; II, V - kh kho sau khi bao hoa trc chat hap thu hoan nguyen; III, IV - kh kho;VI-chat hap thu bao hoa kh kHTBH; VII- chat hap thu hoan nguyen ; VIII- chat tai nhiet; IX- chat hap thu bao hoa deetan; X- chat hap thu bao hoa kh kho hai

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CHNG5. CH BIN KH

-Phng an ba: Bao hoa bang 2 kh kho

Hnh V.20. S o nguyen tac bo phan hap thu vi viec bao hoa trc chat hap thu hoan nguyen bang kh kho cua thap hap thu vthu bay hi ( phng an III) 1,5, 7 - thiet b lam lanh bang propan; 2,6,8 - thap tach; 3- thap hap thu; 4- thap hap thu bay hi (HTBH); 9- noi soi lai I- kh nguyen lieu; II, VI - kh kho sau khi bao hoa trc chat hap thu hoan nguyen; III- chat hap thu hoan nguyen; IV,V - kh kho; Vthu bao hoa kh kho t thap hap thu hoac HTBH; VIII- chat tai nhiet; IX- chat hap thu bao hoa deetan.

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CHNG5. CH BIN KH

- Kh beo trung bnh va T thap (-37oC) :

trng hp I : II III

C3 (%) 76 83 91

C4+ (%) ~ 100

-S o vi bao hoa trc chat hap thu hoan nguyen bang H/C nhe giam chi ph rieng

chat hap thu 20%.

-Co the giam sinh nhiet ca phan di thap hap thu: lay mot phan C4+ ra khoi khnguyen lieu (loai xang kh nguyen lieu)

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CHNG5. CH BIN KH

II.4. S o cong nghe hap thu nhiet o thap(HTN T)

1. Che bienkh thien nhien bang phng phaphap thu nhiet o thap ethu hoi C3+

S o HTNT thu hoi C3+ t kh thien nhien:

- Cong suat: 8,57 ty m3/nam;C3 = 84% - S dung 2 chat hap thu: M = 100 va M =140.

- Thap hap thu (7): 2 khoang oc lap (Ava B):

+ M=100 hap phu kh nang+ M =140(T cao hn) : hap thu M=100

- Thap HTBH (12): Gia nhiet phan dinh 3 dong tuan hoan.

- Thap hap thu (7): 2 khoang oc lap (A

va B):+ M=100 hap phu kh nang+ M =140(T cao hn) : hap thu M=100- Thap HTBH (12): Gia nhiet phan di

nh 3 dong tuan hoan.

Hnh V.24. S o cong nghe HTNT thu hoiC3+ t kh thien nhien. 1, 2, 8, 13,14,15 - Trao oi nhiet; 3, 4,10- thiet b lam lanh bang C3; 5, 6, 11 - thap tach; 7- thap hap thu; 9-

thiet b gia nhiet; 12- thap hap thu bay hi (HTBH); 16- may lanh khong kh; 17- be cha; 18- thap giai hap; 1nung.

I- Kh nguyen lieu; II- dung dch EG; III - kh kho cua thap HTBH sau bo phan bao hoa trc chat hathu hoan nguyen;IV- kh kho t thap hap thu; V- kh kho; VI, XII- chat hap thu M=100 c bao hoa bang chydrocarbon nhe; VII - chat hap thu hoan nguyen vi M= 140; VIII - chat hap thu bao hoa M=100; IX - EG t condensat; XI- kh; XIII- kh kho; XIV- chat hap thu bao hoa loai etan M= 100; XV- C3+; XVI - chat hap thu hoan

nguyen M= 100.

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CHNG5. CH BIN KH

2. Che bienkh thien nhien bang phng phap hap thu nhiet o thap e thu hoi C2+

Hnh V.25. S o cong nghe HTNT thu hoi cac hydrocarbonC2+ t kh thien nhien. 1,8, 12,13 - Trao oi nhiet thu hoi; 2,4,6,10,14,17,19 - thiet b lam lanh bang C3; 3,7,15 - thap tach; 5- thap hap thu; 9 - thap bay hi - tach; 11- thap HTBH; 18- maylanh khong kh; 20- be cha; 21- lo nung. I- Kh nguyen lieu; II- kh kho; III- d.d EG mi; IV - EG bao hoa nc; V- chat hap thu bao hoa; VI- kh kho; VII- chat hap thu bao hoa hydrocarbon nhchat hap thu hoan nguyen; IX- kh kho; X - kh kho t thap HTBH ; XI- chat hap thu bao hoa hydrocarbon nhe; XII - chat hap thu bao hoa, demetan ho

chat hap thu bao hoa loai bo mot phan kh; XIV - kh; XV- C2+.

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3. Che bienkh ong hanh bang phng phap hap thu nhiet o thap e thu hoiC3+ - Cong suat: 1 ty m3/nam.C3+ = 90%. Chat hap thu: phan oan 105 205oC, M= 140.

Hnh V.26. S o cong nghe HTNT dung e tach cac hydrocarbon C3+ t kh ong hanh. 1,2,3,9,13,14,15,16 - Trao oi nhiet; 4,7,10 thiet b lam lanh bang C3; 5,6,11 - thap tach; 8- thap hap thu; 12- thap HTBH;17, 18,20- may lanh khong kh; 19- be cha; giai hap; 22- lo nung. I- Kh nguyen lieu; II- kh kho cua thap hap thu va thap HTBH sau cum bao hoa chat hap thu hoan nguyen; III- dung dch EG; IV - chat hap thu bao honhe; V, XI- kh kho; VI - chat hap thu hoan nguyen; VII- chat hap thu bao hoa; VIII- kh; IX- hydrocarbon ngng tu (condensat); X- etylenglicol ngam nc; XII

bao hoa hydrocarbon nhe; XIII - chat hap thu bao hoa, loai metan; XIV - phan oan hydrocarbon C3+.

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CHNG5. CH BIN KH

III. CHE BIEN KH BANG PHNG PHAP CHNG CAT NHIET O THAP

Kh lam lanh va tang P chuyen sang trang thai long chng cat. Nhiet o soi cua cac kh H/C (oC):

metan: -161,5; neopentan: +9,5; etan: -88,3; isopentan: +27,9;

propan: -42,4; pentan: +36,0 isobutan: -10,2; n-butan: -0,05;

Chenh lech nhiet o soi (Tsoi ) C1 va C2 = 70

oC -160 -170oC, hut chan khong metan ra khoi etan. C2 va C3 = 46

oC,

C3 va iso-C4 : 32oC.

T gia cac H/C nang hn (iso-C6, C7 va nang hn)khong ang ke chng cat khong nhan c cacH/C rieng le co o sach u cao.

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CHNG5. CH BIN KH

Qua trnh chng cat venhiet ong hoc thuan li hn qua trnh hap thu.

CCNT hieu qua cao hn HTNT, thiet b n gian hn.

S khac nhau c ban cua he CCNT so vi NTNT:

nguyen lieu lam lanh,khong tach trc thap chng cat, tach kh kho (san pham

nh) va phan oan H/C ( san pham ay).

Phan loi: phu thuoc vao s o CCNT, thap chng cat chia thanh:

- Thap chng cat- bay hi: nguyen lieu lam lanh a vao gia thap. Hoat ongnh thap

chng cat thuan tuy

- Thap ngng tu - bay hi. hon hp tach vao mam tren cung

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Yeu to anh hng en hoat ong cua thap CCNT:

1. Tang P:

- chi ph lanh cho phan tach kh giam khong ang ke

- chi ph nang lng giam ang ke v qua trnh dien ra T cao hn.

2. Thong so cong nghe- nang lng toi u:

- T lam lanh trc nguyen lieu:-20oC

P = 2,5-3,0 MPa.

C2 = 50%, C3 = 9293%; C4+ = 100%

3. Ty le chi ph tuan hoan lanh thc/ gia tr toi thieu theo tnh toan =1,55-1,78.

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Hnh V.30. S o chng cat nhiet o thap co hai ca nap. 1.Trao oi nhiet;2. thap bay hi propan; 3. thap tach ba pha; 4. may bm; 5. thap chng cat; 6. noi soi lai. I. Kh nguyen lieu; II. kh kho;III. phan oan H/C; IV. DEG 75%;V. DEG 98-99%;VI. chat tai nhiet

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Hnh V.31. S o chng cat nhiet o thap co thiet b gian n turbin. 1,3- Thap tach; 2- may nen kh; 4- trao oi nhiet a dong; 5- bo phan gian n turbin; 6- thap chng cat. I. Kh nguyen lieu; II. kh kho; III. phan oan hydrocarbon; IV. propan

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CHNG5. CH BIN KH

Thong so NTNT CCNT

Nap 1 ca Nap 2 ca

Mc thu hoi:C3 C3+

Nhiet lng lanh, trieu kJ/giNhiet lng nong, trieu kJ/giLng phan oan H/C, ngan tan/namChi ph nang lng rieng, kW.gi

76 83,2

52,546,0 780,1 300

66,379,2

39,234,4

174,3524,2

73,182,3

39,235,6

179,7423,2

- : NTNT - cao nhat, CCNT 1 ca - thap nhat

-Ch so kinh te- cong nghe: CCNT hai ca nap la tot nhat.

CCNT hai ca nap dung cho che bien kh beo e thu C3+ li hn

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CHNG5. CH BIN KH Cac tham so c ban cua cac thiet b NTNT vi deetan hoa trc va thiet b CCNT:

NTNT CCNT

Nhiet o lam lanh thap nhat, oC -37 -30

Chi ph nhiet lng trong thap soi, ngan kJ 569 429

Tong chi ph nhiet lanh, ngan kJ 641 617

Tong chi ph nang lng trong chu trnh lanh,

kW.gi 98,36 98,50

Ty le nhiet lanh va nhiet o chat lam lanh, kJ/oC 322/-43 544/-36

184/-20 73/13

134/0 -

Cong suat lanh nh nhau.

- u iem cua CCNT:

T cao hn ( T be cha hoi lu-30oC).

(Cung : T trong thap tach cua NTNT:-37oC)

CCNTkhong oi hoi thu hoi nhiet lanh condensat tao thanh nhu cau ve thiet b trao oi nhiet t hn

CCNTchi ph nhiet lng trong cac thap soi thap hn (30%).

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IV. NG DUNG CAC QUA TRNH CHE BIEN KH KHAC NHAU Trong thc te ap dung:

+ [C3+] < 350g/m3 : HTNT,

+ [C3+] > 350 g/m3 : NTNT.

Cac thong so anh gia:

1) Ch so chi ph tng oi : Po = P/S

trong o: P- chi ph qui oi ;

S- gia tr thng pham (kh kho + phan oan H/C)

Vi P = C + eK,

C- chi ph san xuat (kh ong hanh va nang lng);

K- au t trc tiep (thiet b ky thuat trc tiep);

e - he so khau hao hang nam (cong nghiep che bien: 0,17)

2) Ch so li tng oi Dt.: Dt. = S P

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Tnh toan: la chon phng an toi u

-Cho HTNT:

+ Ham muc tieu: lng chat hap thu tuan hoan.

+ Cac tham so co nh: P= 3,5 MPa, nhiet o trong bo phan loai xang trc va chat hap thu -

23oC.

-NTNT:

+ Ham muc tieu: nhiet o ngng tu kh.

+ Cac tham so co nh: P bo phan ngng tu kh va cum loai etan cua condensat: 3,5 MPa.

San pham chnh: C3+

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CHNG5. CH BIN KH

- Thay oilng chat hap thu trong HTNT va

T lam lanh kh (NTNT) thay oi lng C3 va C4+

tm gia tr toi u.

-e tm che o nhiet o toi u chon s oNTNT loai

thng, mot giai oan:

+ P = 3,5 MPa, T = -20oC -60oC.

+ S dung chat c che DEG khi Tngng tu < -30oC

+ Lam lanh kh T < -30oC can co lam kho hap thu.

+Kh lam lanh en-30oC bang propan ;

T thap hn: lam lanh noi tieppropan-etan.

+ Chon che o nhiet o toi u cho NTNT: tnh cac ch so kinh te- cong nghe cua qua trnh cho ta

cac nhiet o ngng tu cho trc: -20, -30, -40, -50, -60oC.

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ng dung

-[C3+] < 250 g/m3 : NTNT kinh te hn T = -60oC

Ch co lam lanh propan vaC3+ cao can chon qua HTNT,

-[C3+] = t 250 en 350 500 g/m3: HTNT ~ NTNT

-[C3+] > 350 400 g/m3: NTNT kinh te hn.

(Ttoi u ~ -30oC, chu trnh lam lanh propan).

Can thu hoi C2+ NTNT la phng phap duy nhat e coC2+ =80 85%

- Kh rat beo ([C3+] > 600 g/m3), nhan C3+:CCNT vi hai dong nap nguyen lieu.

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CHNG5. CH BIN KH

Kh beo[C3+] > 350 400 g/m3

- Ch so kinh te - cong nghe: NTNT vi thiet bgian n turbin > NTNT lam lanh noi tiep >> HTNT.

u the cua thiet b lam lanh gian n turbin: mem deo, n gian.- Che bien kh kho: dungNTNT

C2= 40 60%,

C3=90% va

C4+= 98%

- Che bien kh ong hanh:

C2 C3 C4+ Vi chu trnh lam lanh propan va lam lanh noi 0,4 0,9 0,97

Vi chu trnh lam lanh propan-etan 0,60,8 0,95 0,99Vi chu trnh lam lanh propan

+ thiet b gian n 0,6 0,8 0,95 0,99

Vi chu trnh lam lanh propan-etan noi tiep+ thiet b gian n 0,60,8 0,95 0,99

Lam lanh propan + thiet b gian n do thiet b n gian c s dung pho bien nhat khi san pham la C2+ va C3.Cac s o nay co nhng ac iem sau:

- Lam lanh kh : gian t 5,0 xuong 2,8 MPa. - Lam lanh propan va trao oi nhiet: lam lanh en -62oC

ha tiep T trong thiet b gian ap en -87oC.


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Công Nghệ Chế Biến Khí -CHƯƠNG 5. CHẾ BIẾN KHÍ