DA CBK Son MEA Final

8/3/2019 DA CBK Son MEA Final

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PH LC

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M UT xa xa con ngui bit du m v kh t nhin phc v cho cuc sng sinh

hot mc d s hiu bit cn hn ch v rt lng ph nhng h cng coi l mt

ngun ti nguyn v cng qu gi.Ngy nay cng vi s pht trin ca khoa hc k thut, con ngi nh gi v

nhn thc c tm quan trng ca chng i vi s pht trin kinh t ca mi quc gia.

l ngun nguyn nhin liu chnh pht trin cc ngnh cng nghip khc. Du m

v kh t nhin l ngun khong sn khng phi l v tn nn cn bit cch khai thc, ch

bin hp l chng lng ph ngun nguyn liu ny.

Trc y lng du m c khai thc v ch bin gp nhiu ln kh t nhin

khai thc, ngy nay khong cch c thu hp li bi lng du m cng ang dn

cn kit cng vi s pht trin ca ngnh cng nghip ch bin du kh .

Vit Nam ngnh cng nghip ch bin kh v ang trn pht trin . Chng

ta khai thc, xy dng c nhng nh my ch bin ngun ti nguyn ny p ng

c nhu cu s dng nng lng v c c nhiu thnh phm c gi tr kinh t cao.

Tuy cn hn ch v cng ngh nhng n cng ng gp mt phn ln vo s pht trin

kinh t ca t nc.

Kh sau khi khai thc ngoi cc cu t chnh l cc hydrocacbon parafin cn cha

cc tp cht nh: Bi, hi nc, kh tr, CO2, H2S v cc tp cht hu c ca lu hunh.

y l cc thnh phn c th gy tn hi n sc kho con ngi cng nh n lm n

mn ng ng thit b trong qu trnh khai thc v ch bin. c bit vi cc kh nh

CO2 v H2S v vy trc khi a vo ch bin, kh cn phi qua cng on chun b, ti

tin hnh loi b cc tp cht k trn bng cc qu trnh tch bi, tch hi nc v c

bit l lm ngt kh. n Tnh ton cc thng s c bn ca thp lm ngt kh bng

MEA.

Em xin chn thnh cm n thy TS.Nguyn Danh Nhi ngi trc tip ging dy

mn hc v hng dn em hon thnh n ny.

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CHNG I: MT S PHNG PHP LM NGT KH

1.1. Tc hi ca kh Acid v s cn thit phi loi b kh Acid (H2S, CO2)

Trong hn hp kh t nhin, kh ng hnh v kh ho du ngoi kh Hydrocacbon

cn cha mt s kh khc nh: Kh chua (H2S, CO2), ng thi cn cha mt lng

khng ln kh hu c khc nh: COS, CS2, Mecaptan S tn ti ca chng trong kh

s gy cn tr trong s vn hnh v ch bin kh, chng gy n mn thit b, gy ng c

cht xc tc trong ch bin, i vi ngi s dng n c nh hng khng tt n sc

kho, gy nhim mi trng, kh cacbonic c phn t c hi hn. Nhng nu thnh

phn ca chng qu ln th s lm gim nhit tr ca hn hp kh.

Mt khc,Hydrosunfua (H2S) l kh d chy (gii hn chy n rng) l cht khngc mu trng thi rt kh chu. H2S rt c c th gy ng c dn n t vong cho con

ngi khi tip xc lu vi n nng cao trong kh. Cho nn, trong qu trnh vn hnh

kh chng ta phi ht sc quan tm n s an ton thit b, phng r r kh. T nhng

vn phn tch trn chng ta nhn thy s bt li v tc hi ca kh chua H2S, CO2 c

mt trong kh t nhin, kh ng hnh. V th chng ta cn phi loi b chng trc khi

a vo ch bin, ni mt cch khc chnh l lm ngt. Tuy vy, bn cnh s tc hi ca

kh chua, th chng vn c li cn ng dng c trong cng nghip ch bin:+ H2S l ngun nguyn liu quan trng sn xut Lu hunh nguyn cht v

Acid Sunfuaric.

+ CO2 cng l nguyn nhin liu c dng trong cng nghip ch bin thc

phm, trong cng nghip ho cht ho hc, trong nng nghip, trong cng nghip sn

xut ung nc gii kht ...

V vy, khi la chn cc quy trnh lm ngt kh cn phi tnh n mc loi cc

cu t khng mong mun trn v tn dng chng sn xut ra cc sn phm chuyndng cn thit.

* Tiu chun cho php kh chua cn li trong kh sch

- M: Hm lng H2S cho php 5,7 mgH2S/m3kh

- Nga: Hm lng H2S cho php 20 mgH2S/m3kh

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- Vit Nam : Hin nay cha c mt quy nh no c th no, v kh t nhin, kh

ng hnh v kh ha du ca chng ta c hm lng CO2 v H2S thp, (tr kh b Sng

Hng c hm lng CO2 tng i cao)

Ni chung, trong cc quy trnh cng ngh x l kh cn phi lm ngt kh nhm c

mc ch:

- Gim n mn ng ng, thit b trong qu trnh x l kh hay s dng kh.

- Gim thiu kh nng gy ng c cht xc tc trong cc cng on ch bin

su.

- m bo an ton cho sc kho v nhim mi trng.

- p ng tiu chun v cc ch tiu k thut ca sn phm kh thng mi.

- Thu hi khi chua dng cho cc ngnh cng nghip khc, khi hm lng luhunh trong kh l ng k.

1.2. Gii thiu tng qut v cc phng php lm ngt kh:

loi b kh chua (H2S, CO2) v cc hp cht khc cha lu hunh khng

mong mun ra khi t nhin, kh ng hnh v kh ho du. Ngi ta s dng ch yu

yu t l cc qu trnh hp th, tu thuc vo c im tng tc ca cc hp cht ny vi

dung mi cht hp th chng c th hp thnh cc nhm sau. Phng php ha hc,phng php vt l, phng php kt hp vt l v ha hc.

1.2.1. Lm ngt kh bng phng php ha hc

Lm ngt kh bng dung mi hp th ha hc l nhng dung dch nc Alkanol

amin. Cc Alkanol amin thng c s dng l: mondo Etanol amin (MEA), di Etanol

amin (DEA), Diglycol amin (DGA), TriEtanol amin (TEA), Di IzoPropanol amin (DIPA)

Qu trnh lm ngt kh ca cc dung mi ny l qu trnh hp th, trong khi tip

xc v phn ng ha hc vi kh chua. Qu trnh lm ngt kh bng Kalicacbonat cng

thuc nhm ny. Phng php lm ngt ny m bo trit kh chua, vi hm lng

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hp th ca kh chua v cc hp cht khng mong mun khc. Vic ti sinh cht hp th

vt l din ra ca nhiu trng hp khng cn cp nhit m nh gim p sut trong h

thng.

Nhc im ca qu trnh l: cc dung mi hp th c s dng hp th tng

i cc Hydrocacbon, v lm sch trit kh trong nhiu trng hp ch tha mn sau

khi x l b sung bng dung mi alkanolamin.

1.2.3. Lm ngt bng dung mi t hp

Dung mi t hp gm Alkanol amin dung dch nc vi dung mi hu c nh

Sunfolan, Metanol v da trn s hp th vt l ca cc hp cht khng mong mun bng

dung mi hu c v tng tc ha hc vi Alkanol amin, l phn phn ng tch cc ca

cht hp th. Cc qu trnh ny kt hp c nhiu u im ca cht hp th. Cc qu

trnh ny kt hp c nhiu u im ca hp th vt l v ha hc. Chng c th c

s dng lm sch trit khi nhng kh chua H2S , CO2 , COS, CS2 v Mecaptan.

Qu trnh tuy c nhiu u im, c th b sung cho nhau mt cch hon ho,

nhng n khng th khng c nhc im do cc dung mi c s dng, hp th ng

k cc Hydrocacbon (c bit l cc Hydrocacbon vng thm tan tt). iu ny lm hn

ch kh nng ng dng cc qu trnh hp th vt l v ha hc bi v loi tr s thpnhp s lng ln Hydrocacbon nng vo nguyn liu ca h thng sn xut lu hunh

v trong thnh phn ca nh my ch bin kh cn phi c my v thit b tch

Hydrocacbon nng khi kh nguyn liu hoc kh Acid trc khi n h thng sn xut

lu hunh (trong cng ngh cn c giai on thu hi cc Hydrocacbon nng b cun theo

bng cch cho Hydrocacbon khi sch quay vng li t di ln trn dung mi i t

trn xung trong mt thp tip xc, cc Hydrocacbon s b cun theo dng kh, cn dung

mi bo ho kh Acid, v cc hp cht cha lu hunh khc c a sang thp ti sinh).Tuy nhin iu ny khng phi lc no cng ng vai tr ch o lin quan n vic

chn q trnh s l khi H2S v cc hp cht cha lu hunh v cht khng mong mun

khc m km theo l chi ph u t v hot ng b sung trong qu trnh vn hnh.

Cc qu trnh hp th vt l c th kinh t hn, l do cc dung mi hu c m bo thu

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hi chn H2S trong s c mt ca CO2 v cho php thu hi tt cho sn phm lu hunh

khi t l H2S: CO2 .Trong nhng iu kin nht nh, cc qu trnh ny c mt s u im

m ch c th pht hin trn c s phn tch kinh t k thut cao khi H 2S , CO2 ,

Mecaptan v cc hp cht khng mong mun khc da trn hp th ha hc v vt l.

bng I.1 trnh by tm tt mt s quy trnh cng ngh lm ngt kh

Hp th ha hc Hp th ha hcQuy trnh cng ngh Dung mi Quy trnh

cng

ngh

Dung mi

* lm sch bng

Alkacol - Fluor Propylencacbonat

MEA Mon Etanol amin - Selecsol DiMetyl ete

Polyetlenglycol

(DMEPEG), N MetylPi

rrolidon (NMP)DEA Di Etanol amin

ADIP Di Izopropanol

aminEkonamin Di Glycol amin Sun finol Hn hp dung dch nc

Di Izopropanol amin v

Sunfolan

Kalycacbonat thng

thng

K2CO3 nng chy

VeTrockk

Assen ca kim

loi kim nng

chy

K3 ASO3

Rectizol Metanol ( nhit thp)

(*) Tn gi phn hot ng ca dung mi, dung mi l nc

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Cc tiu chun c bn trong vic chn chp hp th cng nh qu trnh hp th

tng ng l:Nng u v nng cui ca cc t khng mong mun trong kh v p

sut lm vic cho trc trong h thng hoc p sut ring phn u v cui ca chng

trong iu kin lm sch. p sut ban u xc nh h thng tun hon ca cht th th

(lu lng ring).p sut lin phn cui (mc lm sch) ph thuc trc ht vo mc

ti sinh cht hp th v p sut cn bng ca kh c hp th trn b mt dung mi

nhit xc nh ch yu da vo h s tun hon v iu kin ti sinh ca dung mi hp

th. V vy, tnh kinh t ca qu trnh c xc nh trong kh nguyn liu (kh chua) v

kh lm sch kh ngt. Trn c s nhng d liu ny ngi ta c th nh gi dung mi

no trong cc dung mi hp th ha hc theo vt l c ng dng hp l nht i vi

iu kin cho trc, sau phi xt n tnh c th ca cc tp cht cha trong kh vcc phng n tng tc c th c ca chng vi dung mi hp th, t mi c th

chn la qu trnh thun li tin hnh kho st kinh t ,k thut.

Tt c cc quy trnh cng ngh c nu trong bng I.1 ngoi tr quy trnh

Vetrocokk, u da trn nguyn tc hp th ha hc hay vt l cc cht cha lu hunh,

oxy khng mong mun v gii hp chng t cht hp th, a kh Acid cha H 2S n h

thng sn xut lu hunh kiu Clase. Quy trnh Vetrocokk da trn nguyn tc hp th

H2S bng dng mi hp th ha hc v xy ha trong thit b ti sinh thnh lu hunhnh s c mt ca ph gia hot tnh trong cht hp th v Oxy i vo y thp ti sinh

cng vi khng. Quy trnh lm ngt kh Vetrocokk thng c s dng lm sch kh vi

nng H2S thp.

1.3. Quy trnh lm ngt kh bng dung mi Alkanol amin

Quy trnh cng ngh lm ngt kh bng cc dung mi Alkanol amin c s tha

nhn v ng dng rng ri trong cng ngh ch bin kh t nhin kh ng hnh v khtrong nh my lc du. Khi p sut ring phn ca cc kh chua thp v trung bnh th kh

nng hp th ca cc Alkanol amin tng theo t l H2S v CO2. 1.3.1. Tnh cht chung

v cc qa trnh lm ngt kh ca cc Alkanol amin

* Tnh cht:

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Cc Alkanol amin lun c s dng lm dung mi hp th ha hc lm ngt

kh l: Mon Etanol amin (MEA), Di Etanol amin (DEA), Di Izopropanol amin (DIPA), Di

Glycol amin (DGA). Nghin cu cu trc phn t ca cc Alkanol amin ta thy n c

cu trc tng t vi NH3. V nguyn tc cng c th dng NH3 loi cc kh Acid ra

khi Hydrocacbon nhng NH3 bay hi rt mnh. Do vy, gy kh khn cho qu trnh vn

hnh v tn tht ln do s bay hi ca n.

Bng I.2 cc amin dng hp th kh axt

Tn ho cht Cng thcMonoetanolamin MEA H2N CH2 CH2 OH

Dietanolamin DEACH2 CH2 OH

HNCH2 CH2 OH

Trietanolamin TEA CH2 CH2 OHN CH2 CH2 OH

CH2 CH2 OHDisopropanolamin DIPA CH2 CHOH CH3

HNCH2 CHOH CH3

Metyldietanolamin MDEA CH2 CH2 OHH3C N

CH2 CH2 OHDiglycolamin DGA H2N CH2 CH2 O CH2 CH2 -

OH

Bng I.3 Mt s tnh cht ha l c bn ca cc Alkanol amin

MEA DEA DIPA DGAKhi lng phn t 61 105.1 133.2 105.1Khi Lng ring, kg/m3 1018 1090 989 1055

Nhit sI,0C p sut Pa

110 Pa 171 248.7 221660 Pa 100 187 1671320 Pa 69 150 133p sut hi bo ho 200C, Pa 48 1.33 1.33 1.33

Nhit ng c,0C 10.5 28 42 9.5 nht tuyt i, Pa.s 0.241

( 200C)0.38( 300C)

0.198( 450C)

0.026( 240C)

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ho tan trong nc 200C,%kl

Hon ton 96.4 87 Hon ton

Nhit ho hi 1.105Pa,j/kg 1486.4 1205.9 722.5 917.4

Mono etanolamin (MEA) l amin c tnh baz mnh nht trong cc Alkanol amindng lm dung mi hp th trong cc quy trnh lm ngt kh. nhit thp n c th

phn ng rt nhy vi cc Acid, n phn ng c c vi H2S v CO2. MEA c khi

lng phn t nh nht trong cc Alkanol amin nn nhit ta ra trong phn ng hp th

cc khi axit l ln nht trong cc Alkanol amin khc. ng thi MEA bn v mt ha

hc, dung dch MEA t b phn hu, MEA phn ng khng thun nghch vi cc

Cacbonyl Sunfua (COS) v Cacbondisunfua CS2 to thnh cc sn phm bn khng ti

sinh c hoc kh ti sinh. V vy, gy tn tht mt lng ln dung mi hp th (nukh nguyn liu c cha nhiu COS, CS2). Mt khc, MEA c p sut hi bo ho cao

nht trong cc Alkanol amin, p sut hi bo ho ca MEA ln hn gp 30 ln so vi p

sut hi bo ho ca DEA v 300 ln so vi TEA. Do , trong qu trnh vn hnh

thng b tn hao mt lng dung dch MEA ng k do bay hi.

DiEtanol (DEA) l mt baz yu hn so vi MEA, cng bn v mt ha hc. DEA

phn ng c vi H2S v CO2 nhng phn ng ca n km hn so vi MEA. DEA cng

phn ng vi COS, CS2 nhng cc phn ng ny xy ra chm hn so vi MEA.

* Cc quy trnh lm ngot:

- Qu trnh lm ngt kh bng dung dch MonoEtanolamin; qu trnh ny c

ng dng rng ri lm sch kh t nhin v kh ng hnh

- Qu trnh lm ngt kh bng dung dch Di Etanol amin (DEA), qu trnh ny

trc y c ng dng ch yu lm ngt kh nh my lc du nhng hin n cng

c ng dng lm ngt kh t nhin.- Qu trnh lm ngt kh bng dung dch Di Glycoly amin (DGA), qu trnh ny

c ng dng loi b trit H2S v CO2, nu dng DGA thay th cho MEA s cho

php gim lu lng ring ca cht hp th v chi ph nng lng l 25 40%.

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- Qu trnh kt hp ng thi va lm ngt va lm kh kh, dng dung mi l

dung dch MEA hoc DEA vi Glycol.

- Qu trnh lm ngt kh bng dung dch TriEtanol (TEA), qu trinh ny c

gii chuyn mn nh gi l khng hiu qu v hin nay c thay th bi qu trnh

MEA v DEA.

- Qu trnh lm ngt kh bng dung dch Di IzoPropanol amin (ADIP), qu trnh

c ng dng lm ngt kh t nhin v kh du m, v n c chi ph vn hnh thp hn

so vi qu trnh MEA.

- Qu trnh lm ngt kh bng dung dch Metyl Dietanol amin (MDEA), qu trnh

c bit c ch , do tnh chn lc ca n cao, khi phn ng vi H2S trong s c mt

ca CO2.Trong qu trnh lm ngt kh ca cc Alkanol amin nu trn, th cc qu trnh

MEA, DEA v ADIP th c ng dng nhiu nht lm ngt kh t nhin v kh ng

hnh.

1.3.2. Quy trnh lm ngt kh bng MEA.

S tng tc ca MEA vi H2S, CO2 theo phn ng sau:

- Vi H2S:

2RNH + H2S (RNH3)2S (I.1)

(RNH3)2 + H2S 2RNH3HS (I.2)

- Vi Cacbonic:

CO2 + 2RNH2 + H2O (RNH3)2CO3 (I.3)

CO2 + (RNH3)2CO3 + H2O 2RNH3HCO3 (I.4)

Vi R nhm HOCH2CH2

II 8 VI

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IV VIII 11

97

VII

S nguyn l cng ngh hp th bng MEA

1. thp hp th; 2,3,4. thit b phn ly; 5,6. thit b lm ngui bng khng kh; 7,8.

thit b lm lnh bng nc; 9. thit b trao i nhit; 10. thp nh hp th; 11. B phn

un nng; I. kh nguyn liu; II. kh sch(kh ngt); III. Dung mi bo ho; IV. kh phnly; V. Dung mi nh hp th mt phn; VI. kh axit; VII. Dung mi ti sinh tun

ho tr li thp hp th.

Trong cc phn ng trn th tc d phn ng ca MEA vi CO2 chm hn so vi

phn ng ca n vi H2S nhit thp cc phn ng xy ra theo chiu t tri sang

phi, nhit cao th cc phn ng xy ra theo chiu ngc li (t phi sang tri).

Trong trng hp u xy ra qu trnh hp th ho hc, H2S, CO2 lin kt vi cht hp

th theo phn ng ho hc (chiu t tri sang phi). Trong trng hp th hai din ra sgii hp (ti sinh cht hp th v tch cc kh Acid: H2H v CO2 c hp th). Nh phn

ng hp th ca cc mui MEA v cc Acid nhit cao. Cc phn ng hp th ho

hc l cc phn ng to nhit rt mnh, ngc li phn ng ti sinh (phn ng phn hu

cc mui) l phn ng thu nhit.

Dung mi hp th ho hc dng trong qu trnh lm ngt kh bng MEA l dung

dch nc Mono Etanol amin, nng MEA trong dung dch khng vt qu 15 20%

khi lng, v khi c nng cao th vn tc n mn kim loi ca n cang mnh do hp

th hm lng kh axit ln (dung dch Alkanol amin tinh khit khng c tnh n mn).

Nng dung dch cng cao th tnh n mn kim loi cng mnh, nn lm hn ch kh

nng tng hiu qu ca qu trnh hp th bng Alkanol amin (v khng th dng cc dung

dch Alkanol amin c nng cao). Gn y ngi ta thm mt s cht c ch qu trnh

12

3

1

0

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n mn cho php tng nng dung dch MEA ln 30% l tng hiu qu ca qu trnh.

Mc bo ho kh Acid ca MEA thng t 0,3 0,4 mol/molDEA.

Qu trnh lm ngt kh bng MEA thng c dng lm ngt kh chua H2S v

CO2 khi p sut ring phn ca chng khng cao hn 0,6 0,7 Mpa.

* nh gi u nhc ca qu trnh lm ngt kh bng MEA.

- u im:

+ MEA c kh nng phn ng cao, n nh v d ti sinh, cng ngh v thit b

n gin.

+ Qu trnh lm ngt kh bng MEA bo m c th tch trit H2S v CO2 ra

khi kh trong khon p sut ring phn ca H2S v CO2 kh rng, c th vn hng qu

trnh hp th p sut khng cao lm. Dung dch Mono Etanol amin tng i kh hpth Hydrocacbon, cn kh nng hp th i vi H2S v CO2 th rt cao.

- Nhc im:

Mc bo ho kh Acid ca dung dch Etanol amin thp, lu lng ring v chi

ph vn hnh cao. Mt vi tp cht (CO2, COS, CS2) cha trong kh nguyn liu, khi

tng tc vi dung mi to thnh cc hp cht khng ti sinh hoc kh ti sinh c. Do

vy lm tn hao mt lng ng k dung mi, lm mt hot tnh cht hp th, lm tng

tnh to bt ca dung mi, ngoi ra quy trnh lm ngt kh ca MEA cn nng lng chovic ti snh dung mi hp th ln hn cc quy trnh khc.

1.3.3. Quy trnh lm ngt kh bng DEA

Nhng phn ng chnh xy ra (trong qu trnh lm ngt kh) gia DEA vi H2S v

CO2;

- Vi H2S

2R2 NH + H2S (R2NH2)2S (I.5)

(R2NH2)2S + H2S 2R2NH2HS (I.6)

Vi CO2:

CO2 + 2R2 NH + H2O (R2NH2)2CO3 (I.7)

CO2 + (R2NH2)2CO3 + H2O 2R2NH2HCO313


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y R nhm C2H4OH

Tng t nh qu trnh lm ngt bng MEA (s nguyn l cng ngh hp th

cng khng khc nhiu), cc phn ng trn cng l phn ng thun nghch, chng xy ra

theo chiu thun (t tri sang phi) nhit thp, v xy ra theo chiu nghch (t phi

sang tri) nhit cao.

Dung mi hp th s dng trong qu trnh lm ngt kh bng DEA l dung dch

nc. Nng ca n trong dung dch dng lm dung mi hp th ph thuc vo nng

kh Acid trong nguyn liu ban u v thng thay i t 20 35% khi lng.

bo ho ca dung dch DEA trong qu trnh SNPA DEA c th t t 1 1,3 mol/mol

DEA (ln hn qa trnh MEA). Tuy bo ho ca dung mi DEA trong qu trnh

SNPA DEA cao, nhng kh nng hp th ca dung mi DEA km hn MEA, do MEAc khi lng phn t nh hn, nn cng mt nng % khi lng MEA c mt nng

mol ln hn nn c kh nng hp th ln hn.

- u im ca qu trnh :

Bo m lm sch trit kh khi cc kh H2S, CO2 vi s c mt ca COS v CS2

(sn phm phn ng gia DEA vi COS v CS 2 b thu phn trong iu kin ti sinh

dung mi cho ra H2S v CO2). Dung dch DEA bn v mt ho hc, d ti sinh trong iu

kin vn hnh ca qu trnh, c p sut hi bo ho thp hn nhiu so vi MEA, s hpth xy ra nhit 10 200C (cao hn so vi qu trnh MEA) nn cho php loi tr s

to bt mnh lit ca dung mi lm ngt kh c nng Hydrocacbon nng cao (hoc c

Hydrocacbon lng trong dung dch).

- Nhc im:

Kh nng hp th dung mi thp, lu lng ring ca cht hp th cao v chi ph

vn hnh ln, mt s tp cht cha trong kh nguyn liu, mt phn CO2 tng tc vi

dung mi to thnh cc hp cht khng ti sinh c, kh nng hp th ca Mecaptan v

cc hp cht hu c cha lu hunh khc thp.

1.3.4. Quy trnh lm ngt bng ADIP:

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Dung mi c dng l dung dch nc diizopropanolamin (DIPA); hm lng

cht hot ng trong c th t n 40%. Nh dung mi ny, vic lm sch trit kh

khi H2S (n 1.5mg/m3) c bo m, diizopropanolamin c th ng thi lm sch kh

khi CO2, COS v RSR. Hot tnh ca dung dch DIPA theo CO2 thp hn so vi dung

dich MEA. Trong qu trnh lm sch c n 40 50% COS v RSR c hp th.

Diizopropanolamin tng tc vi COS, CO2 v RSR to thnh cc hp cht d ti sinh, v

vy s phn hu ca DIPA do tng tc vi cc hp cht cha lu hunh v oxy t hn

nhiu so vi qu trnh MEA (chi ph hi cho ti sinhdung dich DIPA 2 ln nh hn trong

qu trnh MEA vo khong 1kg/m3 kh axit).

ho tan cc hydrocacbon trong qu trnh ADIP khng ln, v vy nng ca

chng khng ln 0.5% th tch. Trong trng hp ng dng DIPA thit b lm sch khc th c ch to t thp cacbon. S cng ngh lm sch bng MEA v qu trnh

ADIP thc t khng khc nhau, v vy h thng lm sch bng Monoetanolamin c th d

dng chuyn i cho hot ng vi diizopropanolamin.

Qu trnh ADIP ng dng rng ri nc ngoi x l kh thin nhin v du

m cng nh kh ca qu trnh xc tc ca cc nh my ch bin m.

CHNG 2: TNH TON CC THNG S C BN CA THPHP TH LM NGT KH S DNG DUNG MI MEA

Tnh ton cc thng s c bn ca thp hp th lm ngt kh bng amin

I.D liu ban u

C1 C2 C3 n-C4 n-C5 H2S CO2 N2%V 80,0 5,0 3,5 2,5 2,0 1,0 2,5 3,5

M 16,043 30,070 44,097 58,124 72,151 34,080 44,010 28,010+Lu lng kh nguyn liu: 4,5.106 Std.m3/ngy m

+Nhit kh nguyn liu: 37oC

+Hm lng kh H2S ra: 85 ppm (V)15


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Vy s mol kh chua vo thp trong 1 gi ( ktc) l :

64,5.10

7934,83[ / ]24.23,63

kcn kmol h= =

Khi lng phn t trung bnh ca kh :

= Mi.yi =0,8.16,043+ 0,05.30,07+0,035.44,097+ 0,025.58,124+ 0,02.72,151+

0,01.34,080+ 0,025.44,01+ 0,035.28,01= 20,218465 dvc

Khi lng phn t trung bnh ca HC

tbHCM =0,8.16,043 0,05.30,07 0,035.44,097 0,025.58,124 0,02.72,151

0,93

+ + + +=

20,19076882 = 20,1908 dvcBc 2: Tnh ton p sut lm vic ca thp hp th

2H SP

Pb

P : p sut lm vic ca thp

2H SP : p sut hi ca H2S trn dung dch MEA ngho 15,3%KL nhit lm

vic ca thp (37oC)

b : Hm lng H2S trong kh ngt T n v oCA, B l hng s P n v mmHg

Theo phng trnh Antoine :2

lg H SA

P BT

= +

p sut hi ring phn ca H2S/MEA(15,3%) 40oC v 100oC

Ti nhit 40oC (313K) c P=2,78477 mmHg

Ti nhit 100oC (373K) c P=3.19469 mmHg

(nhit tnh theo K v p tnh theo mmHg)

Thay cc gi tr P 40oC (313K) v 100oC (373K) vo phng trnh Antoine xc

nh c cc gi tr A v B nh sau :

A = 5350,8 B = 17,54Ti nhit 37oC (313K) p sut hi ring phn ca H2S/MEA

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lgPH2S =5350,8

17,5437 273

+

+= 0,279248

Vy PH2S = 0.279248 mmHg = 37,23 pa

Plv 2H S

P

b = 637,23

85.10 = 4380000 Pa= 4,38 Mpa

(Plv phi nh hn p sut ti hn


19/24

nH2S = nH2S (chua) nH2S (ngt) = 79,3483- 0,6745= 78,6738 [kmol]

nMEAdng hp th H2S = 3 nH2S b hp th = 3. 78,6738= 236,0214 [kmol]

S mol CO2 trong kh chua

nCO2 (chua) = %CO2 (chua). mol kh vo = 0,025. 7934,83= 198,37075 (kmol)

S mol CO2 trong kh ngt

nCO2 (ngt) = %CO2 (ngt). mol kh vo = 0,005. 7934,83= 39,674 [kmol]

Vy s mol CO2 b hp th l:

n CO2 = nCO2 (chua) nCO2 (ngt) = 198,37075- 39,674 = 158,697 [kmol]

nMEA dng hp th CO2 = 3nCO2 b hp th = 3.158,697= 476,091 [kmol]

Tng s mol MEA nguyn cht cn dng:

nMEA = nMEA dng hp th H2S + nMEA dng hp th CO2= 236,0214 + 476,091= 712,1124 [kmol]

Vy Lng dung dch MEA 15,3% bm vo thp trong 1h l.

mMEA(ngho) = nMEA .MMEA /%MEA = 712,1124.61,08.100/15,3%

= 284286,4405 [kg]

Lu lng tnh theo kg/h ca dung dch amin ngho

mMEA(ngho) = (namin.M amin/C% amin) + mCO2 ngho + mH2S ngho

= 284286,4405+ 6268,0133+ 485,3755= 291039,8293 [kg]

Vi:

mCO2/MEA ngho = nCO2/MEA ngho .MCO2 =0,2. nMEA(nc). MCO2

=0,2. 712,1124.44,01 =6268,0133 [kg]

mH2S/MEA ngho = nH2S/MEA ngho .MH2S =0,02.nMEA(nc). MH2S

=0,02. 712,112.34,08=485.3755 [kg]

Bc 4: Lu lng dung dch amin giu ra y thp

mMEA (giu) = mMEA (ngho) + mH2S(ht) + mCO2(ht) +mHC(ht)

ta chn s mol HC b hp th ti a l 0.5% th tch

Khi lng HC b hp th :

nHC = 0,5%.nkc. M = 0,005. 7934,83.20,1908= 801,0528 [kg]

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b. Nhit thu Qthu gm (mc ny T n v oC)

Nhit cn thit un nng dung dch MEA ngho (khng tnh lng

H2S) t Tdd ti T vo:

min min4 min min omin

.[ ]. .( )%

A A A A nghA

n MQ C T T C=

CAmin= 1,6927 [kJ/kg-C]

Q4 = 284286,4405.1,6927.(T-40)= 481211,6578.(T-40) [kJ]

Nhit em H2S b hp th t Tkh chua n T

Q5= nH2S(hp th) . MH2S.CH2S.(T-Tkh chua)

CH2S = 1,0165 [kJ/kg-C]

Q5= 78,6738.34,08. 0,7724 (T 37) = 2070,9613(T-37) [kJ] Nhit cn un nng H2S c sn trong dung dch amin ngho

CH2S = 1,0171[kJ/kg-C]

Q6= nH2S (ngho).MH2S.CH2S.(T-Tamin ngho)= 0,02.7934,83.34,08.0,7171.(T-40)

= 3878,3494.(T-40) [kJ]

Nhit cn un nng CO2 b hp th

2COC = 0,8813 [kJ/kg-C]

2 2 27 ( ) . . .( )CO ht CO CO kcQ n M C T T = = 158,697.44,01.0,8813.(T-37) =6155,2239.

(T-37) [kJ]

Nhit cn thit un nng CO2 c sn trong amin ngho

CCO2 = 0,8833[kJ/kg-C]

Q8 = nCO2(ngho).MCO2.CCO2.(T-Tamin ngho)

Q8 = 0,2.7934,83.44,01.(T-40)= 69842,3737[kJ]

Nhit cn thit un nng kh hydrocarbon b hp th l:

CHC (ht) =0,8.2,2801 0,05.1,8213.0,025.1,7712 0,02.1,7626

0,8 0,05 0,025 0,02, 0,895

+ +

+ + + += 2,2114 [kJ/kg-C]

C1 C2 C3 n-C4 n-C5 Tng

% th tch 0,8 0,05 0,025 0,02 0,895

Nhit dung 2,2801 1,8213 1,7712 1,7678 1,7626

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ring

Q9=mHC b hp th.CHC.(T-Tamin)= 3540,519.2,2114.(T-40)

=7829,5037.(T-40) [kJ]

Nhit lng tht tht bn ngoi ly ti a bng 5% tng nhit ta

10 0,05Q = .Qta= 0,05.(Q1+Q2+Q3)= 0,05.( 5107691,906 +13388816,84

+3527035,478) = 1101177,211 [kJ]

Vy tng lng nhit thu vo l:

QThu= (Q4+Q5+Q6 +Q7+Q8+Q9+Q10)= -0,05208.109+1672165.281.T [kJ]

QThu = - Qta10

1 2 3

4

( ) 22023544,22ii

Q Q Q Q=

= + + = [kJ]

p dng phng trinh cn bng nhit trn ta tnh c nhit dng MEA giu ra

khi y thp:

Nhit dng amin giu ra khi y thp T = 44,318oC

Bc 7: Tnh s a l thuyt ca thp

Nlt = (*)

Trong A l yu t hp th, A =

2

2

( )

( )

H S kn

H S kc

nq

n= =

685.10

0,01

= 85.10-4 =0,0085

a : Phn mol H2S trong kh nguyn liu, a=0,01

R : t s mol Amin/s mol H2S, R =3:1

r : s mol H2S cn li trong amin ngho, 2min

0,021

H S

a

nn

=

p : p sut lm vic ca thp, p= 4,38 Mpa

p1 : p sut ring phn ca H2S trong amin giu

Tnh theo phng trnh Antoine

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Trong dung dch amin ra ta c :

2lg 0,1284H S

Bp A

T C= =

+ 2337,5278H Sp=> = [mmHg]= 0.045 [Mpa]

A B C

8,02401 1921,0 203,3T: nhit [oC]

2H Sp p sut ring phn ca H2S [mmHg]

Thay cc thng s trn vo (*) ta c A,A=1,02

Nlt=1

ln0,0085(1,02 1)

1ln1,02

+ =

9,6995

Bc 8: Tnh s a thc ca thp

Nthc=ltN

trong hiu sut lm vic ca a vi kh 0,25 0,4

N thc=9,6995

24, 2488 250, 4

= ; [a]

Bc 9: Tnh ng knh thp hp th

0,1. .0,0114

.

Q TD

p=

Trong

D: ng knh thp

Q : Lu lng kh nguyn liu, Q= 4,5.106/24= 187500 [m3/h]

T : Nhit lm vic ca kh nguyn liu, T= 310 [K]

: Vn tc tuyn tnh ca kh trong thp, chn = 0,13[m/s]= 468 [m/h]

P : p sut lm vic ca thp, p= 4,38 [Mpa]

Vy ng knh thp D = 0.6071 [m]Bc 10: Tnh chiu cao ca thp

H= Nthc .d + h

d : Khong cch gia cc a chn d=0,50,6 [m]

h : Chiu cao b tr gm chp trn v chp di thng ly h= 1,21,6 [m]

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H = 25.0,5 + 1,2 = 13,7[m]

KT LUN

Vi dng kh nguyn liu c hm lng CO2 l 2,5% v H2S l 1% lm ngt dng kh

ny phi dng thp hp th ti thiu p ng cc iu kin sau:+chiu cao 13,7 m

+ng knh 0,6071 m

+p sut lm vic 4.38 Mpa

TI LIU THAM KHO

[1] CNG NGH CH BIN KH THIN NHIN V KH DU M ngi

dch: Hong Minh Nam- Nguyn Vn Phc- Nguyn nh Soa- Phan Minh Tn

[2] TS. Trn Xoa, TS. nguyn Trng Khung, K s H L Vin. S tay qu trnh

v thit b cng ngh ha cht tp 1

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DA CBK Son MEA Final

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