M phng HYSYS qu trnh lm kh kh bng pp hp th MEG 1 | P a g e 1 LHDK52 Nhm 5 Li M u Khnghnhvkhthinnhinkhaithctlngtthngbohahi nc v hm lng hi nc ph thuc vo p sut, nhit , v thnh phn ha hc ca kh. Mi mt gi tr nhit v p sut tng ng vi hm lng nc cc i c th nht nh. Hm lng m tng ng vi hi nc bo ha ti a c gi l m cn bng. Hm lng hi nc trongkhng hnhvkh thin nhin cn phi bitv hi nc c th b ngng t trong cc h thng cng ngh x l sau ny, hnh thnh cc hydrat ( cc tinh th cht rn ) d ng cc chim cckhongkhng trong cc ngdnhayccthitb,phviukinlmvicbnhthngiviccdy chuyn khai thc, vn chuyn v ch bin kh. Ngoi ra s c mt ca hi nc v cc hp cht cha lu hunh ( H2S v cc cht khc ) s l tin thc y n mn kim loi, lm gim tui th v thi gian s dng ca cc thit b, cng trnh. Trcnhngnguycvtchitolncahinccmttrongkhthin nhin v kh ng hnh trong cc quy trnh cng ngh th vic lm kh kh sao cho t yu cu v tiu chun k thut l mt nhimv bt buc m bokh nng hot ng n nh v hiu qu ca cc dy chuyn cng ngh ch bin cc sn phn kh sau ny. Kh c sy kh vi mc ch tch hi nc v to ra cho kh c nhit imsngtheoncthphnvinhitcctiumtikhcvn chuyn hay ch bin. Do vy, mc ch ca n ny l thit k mt s cng ngh lm kh kh bngphngphpHpthdngMonoEtylenGlycol(MEG)bngphnmmm phng Hysys. M phng HYSYS qu trnh lm kh kh bng pp hp th MEG 2 | P a g e 2 LHDK52 Nhm 5 Chng I - Tng quan v qu trnh cng ngh sy kh kh I.C s l thuyt Hydrat l nhng hp cht c th tn ti mt cch bn vng di dng tinh th. Thc cht l nhng dung dch rn, trong cc phn t nc dung mi nh cc lin kt hydro to thnhkhung hydrat. Trong cckhoang cakhung ny cc phn t kh c kh nng to hydrat nh metan, etan, propan, isobutan, nit, H2S, CO2, argon schimch.Cchydrocacbonviphntcancthxmnhpvokhung cngvi cc phn tkh ckch thc nh hn, dn ti thay i p sut cn bng trn cc hydrat. Mc chim ch trongkhung ca cc phn tkh to hydrat i vithnhphnkhchochyuphthucvopsutvnhitcah.Cc tinhthhydrathnhthnhtrnbmtphnchiaphacahkh-nc.Nctdo cn li sau khi hnh thnh cc hydrat ch tip tc chuyn thnh trng thi hydrat khi c skhuy trn cc phavkhi c nhng iukinnhit ng thch hp. Khi khng c s khuy trn th qu trnh khuch tn ca kh qua lp mng cng ca cc hydrat rt kh khan v s pht trin lin tc ca cc hydrat s khng xy ra. iukinhnhthnhcchydratngoiracnphthucvohmlngca muictrongnc,hmlngcachngtngsdnngimnhitbtu tothnhhydrat.Nhitnycngphthucvothnhphnkh,vdnhit bt u to thnh hydrat ca metan khi c mt propan, CO2, H2S s thp hn so vi khi vng mt cc cht ny. Hnh dng ca hydrat rt a dng, n c xc nh bi thnh phn kh v cc iu kin nhit ng hc. Thng thng v hnh dng chng ging nh nc hay tuyt m nn. Nhm ngn nga s hnh thnh cc hydrat ngi ta s dng rng ri phng phpcchtclphngphpavodngkhccchtkhcnhaugilcc chtcchlmhnhittothnhhydratnhmethanol,glycolvphng php lm kh (tch nc) kh da trn c s tch hi nc ra khi kh bng cc cht hp th lng hoc rn. -Phng php c ch: thc cht l cho cht c ch vo dng kh m, cht c ch s tan trong nc t do, kt qu l lm gim p sut hi nc v h nhit to thnh hydrat. Hin nay cc cht c ch ngn nga s to thnh hydrat thng dng nht l: oSdngchtcchlmethanol,cnckhuvckhhydratvkhuvc kh axit. oS dng cht c ch glycol M phng HYSYS qu trnh lm kh kh bng pp hp th MEG 3 | P a g e 3 LHDK52 Nhm 5 Trong thc t thng s dng cc loi glycol: EG, DEG,TEG vi nng khong 60 - 80 %khi lng. Vic la chnmt loiglycol s dng t hiu qu cao chomt qu trnh x l kh no ph thuc vo : T ng c v nht ca dung dch glycol ; h T to hydrate i vi nng glycol cho ; kh nng ha tan ca glycol trong HC ngng t ; thnh phn kh. h T im sng ca kh ph thuc vo loi cht c ch,nng ca n v T kh tip xc vi cht c ch . Nhng u im m cc glycol c c GlycolMetanol Khng gy c vi ngi v mi trng. Gy c hi vi ngi v mi trng. C p sut hi bo ha rt thp v c kh nng thu hi rt cao bng phng php vt l n gin l c c cc dung dch nc cha glycol. p sut hi bo ha cao do vy kh tch ra khi dng kh, vic ti sinh n rt phc tp nn vic tiu hao cht c ch l ln. Nhit si cao nn kh b bay hi. Trnh mt mat khi thit b. Nhit si thp nn kh nng tht thot l rt cao. Khng gy n mn cho thit b.Mt s phn xng i khi cn thit k thm cc thit b loi axit c th sinh ra. -Phng php hp ph: cc phng php hp ph cho php t im sng theo mtrongkhong100200oCvsysukhnimsng-85-100oC.Cc cht hp ph c th chia thnh : Boxit l khong thin nhin cha ch yu l oxit nhm ; oxit nhm hot ha l Boxit lm sch ; cc loi Gel l nhng hp cht cu to t oxit silic v alumogel ; cc ry phn t l cc zeolite. Cc cht hp ph c b mt ring rt ln ( 500-800 m2/g ) v b mt ny c to thnh t cc mao qun hay mng tinh th. Cc qu trnh hp ph c th thc hingin on trong cc thit b vi tng thp hp ph c nh hoc lin tc vi cc thit b cha cc M phng HYSYS qu trnh lm kh kh bng pp hp th MEG 4 | P a g e 4 LHDK52 Nhm 5 lp hp ph chuyn ng. Tuy nhin cc qu trnh lin tc rt t kh c s dng do cc thit b cng ngh rt phc tp. -Phng php thm thu kh: Cho n nay, qu trnh dehydrat ha bng thm thu khhunhkhngcncsdngtrongcngnghipxlkhnadonhng yu cu k thut qu cao ca qu trnh. dshydrat ha kh bng thm thuphi la chn nhng hp cht cao phn t thch hp c ij rt ln, khong 200.000 (vi loimngmngngthvkhnghckhuyttt)vkhong300500(vi loi chm si rng). Hn na, phi chp nhn mt lng C1 thm thu quamng lc mng lc c chn c b mt ring khng qu ln. -Phngphphpth:phngphphpthcsdngrngrisykh kh ti cc cng trnh ng dn kh cng nh trong cc nh my ch bin kh. Cht hpthsykhlnhngdungdchncmccamono-,di-v trietylenglycol. S sy kh kh bng cc cht hp th ny da trn s khc bit v psutringphncahinctrongkhngkhvtrongchthpth.Gitr im sng ca kh c m bo bng dung dch Glycol. So snh u nhc im ca cc dung mi hp th nc: u imNhc im MEG t tan trong kh ngng t. Dung dch m c khng b ng c. nht thp tng kh nng tip xc vi hn hp kh. C kh nng ngn nga to hidrat cao hn DEG v TEG p sut hi bo ha cao hn DEG v TEG. Nhng ha tan trong HC cao hn DEG v TEG DEG ht m cao, kh bn khi c mt cc hp cht lu hunh, O2 v CO2 nhit thng. Dung dch m c khng b ng c. nhit cao c chn lc cao Tiu hao do tht thot cao hn TEG. Khi ti sinh kh thu c DEG nng >95%. im sng thp hn so vi TEG. Gi thnh cao TEG ht m cao. To im sng cho kh sy cao (27.8 47.3oC) bn cao khi c mt cc hp cht lu hunh, O2 v CO2 nhit i hi chi ph u t cao. Dung dch TEG c kh nng to mng khi c mt cc HC nh. ha tan M phng HYSYS qu trnh lm kh kh bng pp hp th MEG 5 | P a g e 5 LHDK52 Nhm 5 u imNhc im bnh thng. Khi ti sinh d thu c nng cao >99%. Dung dch khng b ng c. bay hi TEG thp hn DEG ca cc HC nh trong TEG cao hn DEG Metanol Gi thnh r. c s dng ch yu trong cc h thng vn chuyn. iu kin thng dung dch m c khng bng c. C nht thp nht nn kh nng tip xc vi hn hp kh l cao hn cc glicol C p sut ring phn cao ln kh tch ra khi kh khi ti sinh. Tiu hao ln c tnh vt l ca cc Glycol v Metanol (dng lm kh kh) C TNH VT L MEGDEGTEGTREGMETANOL Cng thc H3C-CH2-CH2-OH HO-(CH2-CH2-O)2-H HO-(CH2-CH2-O)3-H HO-(CH2-CH2-O)4-H CH3OH KLPT62.1106.1150.2194.232.04 im si p sut 760mmHg, (oC) 197.3224.8285.531464.5 p sut hi 25oC, (mmHg) 0.12