bo co pro/II

PRO/IIFlash-Distillation-Shortcut-Side Column-Case study-Calculator-Optimizer

MC LCA.TNG QUAN V PRO/II3I.Gii thiu phn mm PRO/II3II.By bc s dng phn mm PRO/II:31) V s qui trnh sn xut:32) nh r nhng thnh phn43) La chn nhng phng thc tnh ton nhit ng:54) nh r nhng dng c nhp liu:65) Cung cp nhng iu kin cho qui trnh76) Chy m phng87) Xem kt qu8III.S mt quy trnh dng phn mm PRO/II8IV.Nhp d liu v chn thut ton81) Nhp d liu:8 2) Chn thut ton:9V.KIM TRA TIN CY CA KT QU10B. CC THIT B V CNG C C S DNG11I. Flash111) Tng quan112) Phng php tnh ton123) Flash drum13II. DISTILLATION131) Thut ton Inside Out :142) Thut ton Chemdist163) Thut ton Eldist184) Tnh ton thu ng lc hc cho thp chng ct205) Tc v kch thc ca thp a21III. SHORTCUT241) Gii thiu tng quan242) Phng php tinh toan253) Phn loai m hinh chng ct:274) Phn loai:27IV. SIDE COLUMN291) Gii thiu292) Phn loai:293) Phng php tinh toan:31V. CASE STUDY321) Chy mt Case study322) Xem kt qu case study34VI. CALCULATOR341) Tng quan342) Calculator setup353) Calculator procedure:40VII. OPTIMIZER :45C. BI TON49Bi ton 1: Chng ct lin tc hn hp benzen v toluen49Bi ton 2: Tnh ton thit b tch lng kh - Flash66D. TI LIU THAM KHO71

1. TNG QUAN V PRO/II1. Gii thiu phn mm PRO/IIPhn mm PRO/II l phn mm tnh ton chuyn dng trong cc lnh vc cng ngh ha hc ni chung, c bit trong lnh vc ha du, lc du, polymer, ha dc... L sn phm ca SIMSCI, hnh thnh t nm 1967 v c chnh thc s dng vo nm 1988 sau nhiu ln ci tin. y l phn mm tnh ton rt chnh xc cc qu trnh chng ct. PRO/II l cng c tnh ton d dng cc cn bng vt cht v nng lng, nhm m phng quy trnh trng thi n nh; theo di, ti u ha, ci thin nng sutPRO/II vn hnh theo cc modul lin tip, mi thit b c tnh ring r v ln lt tnh cho tng thit b.PRO/II bao gm cc ngun d liu phong ph: th vin cc cu t ha hc, cc phng php xc nh cc tnh cht nhit ng, cc k xo vn hnh cc thit b hin i cung cp cho cc k s cng ngh cc k nng biu din tt c cc tnh ton cn bng vt cht v nng lng cn thit khi m phng cc trng thi dng ca cc s cng ngh.Phn mm PRO/II c s dng nhm hai mc ch: Thit k mt phn xng mi (Sizing) M phng mt phn xng c xy dng trong thc t nghin cu cc yu t nh hng n s vn hnh ca n (Rating) nh: thay i ngun nguyn liu, iu kin vn hnh hoc tiu chun k thut ca sn phm,1. By bc s dng phn mm PRO/II:1) V s qui trnh sn xut:- M mt bn s qu trnh mi: menu file/New- To dng bn s qu trnh: ln lt b tr, sp t tng thit b v dng ln s PFD.- t tng thit b ln s PFD bng cch click chut vo biu tng tng ng trn Bng cng c palette v sau click chut ln na vo v tr trn S PFD ni mun t thit b.- Click chut vo nt bm Streams trn bng palette. By gi ta c th thm cc dng vo s qu trnh bng cch click chut ln na ti im khi u ca dng, sau click chut ln na ti im kt thc. Tip tc cho n khi mi dng c a vo S PFD.

2) nh r nhng thnh phn - Click chut vo biu tng phn t benzen trong mu trn thanh cng c chn cc cht thnh phn c mt trong qu trnh m phng, ca s Component Selection s hin ra. - Click vo tab Select from List ri nhp cc cht thnh phn (bng cch nh tn, click Add) vo ca s Component Selection.

3) La chn nhng phng thc tnh ton nhit ng:- Kch nt s pha chn nhng phng thc nhit ngtdanh sch nhng phng thc thng s dng, cc mi tng quan tng qut, cc phng php v hot ng ca cht lng, cc chng trnh c bit, cc phng php do ngi s dng a vo hay cc phng php v phng trnh trng thi.

4) nh r nhng dng c nhp liu:Nhn p vo mi dng nhp liu ngoi cung cp d liu dng (lu lung, thnh phn, nhit , p sut ).

5) Cung cp nhng iu kin cho qui trnh- Nhn p vo mi biu tng n v hot ng trong s qui trnh sn xut , v cung cp d liu ( nhng vng d liu uc phc tho mu ). Khi nhp d liu qu trnh, vng d liu thay i mu t n xanh.

6) Chy m phng- Click chut vo nt bm trn thanh cng c ca s chnh PRO/II bt u thc hin vic tnh ton.7) Xem kt qu- Sau khi chy xong qu trnh m phng, click vo biu tng trn thanh cng c xut kt qu ra file excel. 1. S mt quy trnh dng phn mm PRO/II

1. Nhp d liu v chn thut ton1) Nhp d liu:Khi nhp d liu cn ch n tnh hp l cc thng s cng ngh thc t, do thit b c th b h hng v cho kt qu sai m khng bit.Chng trnh mun hi t cc thng s phi tng ng v hi ho vi nhau.Mt thng s khng hp l lm qu trnh tnh ton khng hi t lm khng bit nguyn nhn.Qu trnh nhp d liu ch cn nhp mt phn cc gi tr cn thit, cc thng s cn li c tnh ton khi chy chng trnh. Thng s c chia ra lm 3 loi: Thng s khng i: l thng s gi c nh trong sut qu trnh tnh ton nh p sut, nhit , lu lng dng trch ngang Thng s c lng: l thng s phi khai bo hoc khng cn khai bo tu . i vi thng s ny, b tnh ton xem nh l gi tr u ca thut ton lp, kt qu tnh ton c th khc so vi gi tr c lng ban u. Tuy nhin kt qu c lng phi gn k vi gi tr kt qu th chng trnh mi hi t. Thng s khng cung cp: l thng s khng cn nhp, c phn mm qui nh.Khi nhp xong d liu vo, thng s chuyn sang mu xanh. Nu d kin vn cn thiu th c mu v cn b sung cho khi no chuyn sang mu xanh th mi c chy chng trnh.2) Chn thut ton: Trong qu trnh lp, PRO II cn cc gi tr ban u ca thng s, t PR II t ng c lng bng cng c IEG da trn cc thng s cung cp. IEG ch c s dng hai thut ton lp I/O v Chemdist trong PRO/II. Khi m phng qu trnh chng ct du m th I/O thng c s dng v gii nhanh v ph hp cho cc h Hydrocacbon. Phng php tnh lp I/O (inside/outside): chia cng vic tnh ton thnh hai vng lp, vng lp ni v vng lp ngoi.Vng lp ni PRO/II gii cc phng trnh ca ct chng ct: phng trnh cn bng vt cht, cn bng nhit v iu kin bin. Vng lp ni dng phng php tnh gn ng nn xc nh cc bin s rt nhanh. Sau khi vng lp ni hi t (sai s gia hai ln lp t yu cu) th PRO/II chuyn sang tnh vng lp ngoi. Ti vng lp ngoi, s tnh cc gi tri nh K ( bay hi tng i ), H (enthalpy) da trn kt qu vng lp ni v thnh phn, nhit . Vic tnh ton cc phng trnh nhit ng c th chim ti 80% thi gian tnh ton v y l cc phng trnh phc tp v thnh phn v p sut.PRO/II chia lm hai vng lp ni v ngoi gim s ln gii cc phng trnh nhit ng, trong c vng lp ni tnh ton gn ng.

Lu tnh ton ca phng php I/OKhi chng trnh khng hi t, c nhiu nguyn nhn dn n khng hi t: Thng s u vo khng chnh xc, d kin b thiu hoc qu chc ch nn khng thc hin c. Do m hnh khng hp l nh khng s mm l thuyt, thut ton chn sai, b tnh ton tnh cht khng ph hp Do thng s mc nh cho phn mm khng thch hp: mc d qu trnh hi t nhng khng s vng lp nn khng c p s, do vy cn phi tng thm s vng lp ti a cho php hoc gim h s damping Sai s khc khe, kh t c 1. KIM TRA TIN CY CA KT QUKhi phn tch kt qu v thy m hnh tnh ton ph hp qui trnh thc t th kim tra tin cy ca kt qu tnh tonbng cch: Thay i b tnh ton tnh cht (phi ph hp vi h ang m phng). Thay i cu t gi ca dng nhp liu Khi tng s cu t gi m kt qu tnh ton chnh lch khng ng k th phi ly kt qu mi chnh xc hn.Ni chungbc kim tra tin cy khng nht thit phi c thc hin nu khng c mi nghi ng no.1. MT S CNG C H TR B phn ngng t Sn phm nh t thp c b phn ngng t tng t nh sn phm t reflux accumulator drum. Vic la chn b phn ngng t ty thuc vo cc yu t: Thnh phn, nhit bay hi, nhit lm vic, nhit qu lnh, B phn un li (ni un li) Thng c t mc nh dng tiu chun (kettle). i vi thut ton I/O v I/O m rng, ta c th dng cc dng: ni un li c iu chnh lu lng v ni un li khng iu chnh lu lng. i vi cc thut ton khc th ch c th dng ni un li tiu chun. B phn lm nng, lm mt Cc b phn ny i km vi my bm, nng sut m dng ch qu trnh lm mt, nng sut dng cho qu trnh lm nng. Khng c gii hn v s lng cc b phn ny.i vi mi b phn lm nng, lm mt, cn khai bo cc thng s: s mm, nng sut (c du ph hp).B. CC THIT B V CNG C C S DNGI. Flash1) Tng quanThit b phn tch cn bng pha m phng cc hot ng da trn s cn bng pha. Cth dng m phng 1 s thit b cn bng n gin nh thit b bc hi, thit b lng gn, c c..2) Phng php tnh tonPro/II cha nhng phn tnh ton cho nhng trng thi cn bng tch chng hn nh flash drums, mixers,valves,splitters. Flash calculations cng thng c dng xc nh trng thi nhit ng ca mi dng vo cho mt s n v vn hnh . i vi Flash calculation cho 1 vi dng, y c s tng cng ca NC v 3 mc ca t do. NC l s ca tt c cc cu t trong dng ny . Nu thnh phn cu to ca dng v t l c trn ln th cng c 2 bc t do cng c trn. V d nhit v p sut ca tch ng nhit. Ni thm , i vi tt c cc n v vn hnh, Pro/II cng c th biu din 1 Flash calculation trn dng sn phm ti iu kin u ra. S khc bit enthalpy ca dng sn phm v dng vo l net duty ca n v vn hnh.

H thng cc phng trnh: Tng cn bng khi lng : Cn bng cho cu t

Cc trng thi cn bng

Cn bng nhit:

3) Flash drumn v ca Flash drum c th c vn hnh vi nhng thng s iu kin , ng nhit m sng , m si bt khc nhau m si bt cng c th c xc nh cho pha hydrocacbon hay pha nc . m cao hn m sng cng c th c xc nh cho tng dng. Ni thm, i vi 1 s dng tng qut c bit nh tc cu t hay l c tnh dng c bit chng hn nh sulfur c cha p sut v nhit .

II. DISTILLATIONi vi hu ht cc h, SimSci thng s dng thut ton I/O. Khi 1 bi ton c th s dng nhiu hn 1 thut ton th thut ton I/O thng hi t nhanh hn.1) Thut ton Inside Out :Thut ton ny trong PROII da trn mt bi vit ca Russell vo nm 1983. Thut ton ny cha mt s thuc tnh mi m gp phn to nn tnh cht hi t tuyt vi ca n. Thut ton ny c chia ra vi 2 vng lp l vng lp trong v vng lp ngoi. vng lp trong th nhit, vt cht, v nhng c tnh thit k k thut c gii quyt. Nhng m hnh nhit ng n gin cho enthalpy v gi tr bay hi tng i K c s dng trong vng lp trong. Cng vi nhng m hnh n gin th s la chn bin ban u cho php vng lp trong gii quyt mt cch chnh xc v ng tin cy. vng lp ngoi nhng thng s ca m hnh nhit ng n gin c cp nht da trn nhng thnh phn mi v kt qu ca qu trnh tnh ton nhit ng cht ch. Khi no m gi tr cc gi tr Enthalpy v K tnh c ph hp vi m hnh nhit ng n gin v cc c tnh thit k k thut c tha mn th thut ton c gii quyt xong.Nhng bin u tin trong vng lp trong l nhng yu t stripping v yu t dng hi lu. Nhng phng trnh ca mt vng lp trong bao gm phng trnh cn bng enthalpy cho cc a v phng trnh ca cc c tnh thit k chi tit k thut. Yu t stripping c nh ngha nh sau: Trong :Sj = yu t Stripping ca giai on jV = the net vapor leaving the stage (lng hi ri khi a)L = the net liquid leaving the stage (lng lng ri khi a)Kb = the base component K-value from the simple K-value model (gi tr K ca m hnh nhit ng) Vng lp trong gii h phng trnh sau:Trong Hj :Nhit cn bng cho mi mm.SPk : cc c tnh thit k chi tit k thutH phng trnh ny c gii bng phng php Newton-Raphson. Vng lp ngoi: Vng lp ngoi trong thut ton ny cp nht d liu t nhng thng s ca cc m hnh nhit ng n gin v kim tra s hi t. vng lp trong, nhng phng trnh chng ct c tnh ton cho m hnh nhit ng hin hnh. S kim tra hi t trong vng lp ngoi so snh vi nhng tnh ton cht ch cc gi tr enthalpies v cc gi tr cn bng lng hi K t nhng thnh phn mi ( kt qu tnh ton t vng lp trong).Gi tr ban u K b trn mi a c tnh nh sau :2) Thut ton ChemdistChemdist l 1 thut tan mi c SimSci pht trin tnh ton m phng cho hc l tng khng cao. Chemdish l phng php thun Newton Raphson vi vic phn tch y nhng pht sinh, bao gm pht sinh trong hot ng v trong h s nht. Chemdish cho php 2 pha lng c to thnh trn bt k a no trong thp v cung cp cu hnh ca 2 pha lng ngng t. Chemdish vi nhng phn ng ha hc cho php th tc In-Line cho nhng phn ng phi ng lc hc.Chemdish trong Pro/II l phng php Newton ph hp gii quyt nhng vn chng ct phi l tng lin quan n 1 s lnh vc trong ha hoc (nh khong 10%). Nhng iu kin ny l nhng va chm chung trong chng ct nh chng li phn on th khi m l ra nn la chn phng php I/O. Chemdish dng gii quyt tt c vn cn bng hi- lng v cn bng hi- lng- lng nh mt phn ng ha hc.

Biu cn bng a cho trng hp chngct 2 pha khng c phn ng ha hc.Nhng biu thc c miu t nh sau:Cn bng khi lng:

Cn bng nng lng:

Cn bng lng hi:

S phn mol:

Fi = tng dng nhp liu mm th iLi = tng dng lng t mm th iVi = I tng dng kh t mm th iQi = nhit cung cp cho mm th iTi = nhit mm th iX i,j = ln(x i,j) ca phn mol lngY i,j = ln(y i,j) ca phn mol khNC = s cu t NT = s a3) Thut ton EldistEldish l dng m rng ca Chemdish p dng cho muchng ct dung dch cht in li.N c gii quyt nh s dng nhm phn mm th 3 t h thng OLI. My tnh tnh ton trc tip gi tr bay hi tng i K m c chuyn ha thnh K cn bng.Sau Eldish dng ga tr ny tnh ton cn bng lng- hi.Thut ton Eldist trong pro/II l s kt hp ca phng php Newton c s dng trong Chemdist gii phng trh MESH v gii quyt phng trnh ring cho pha lng c m t trong m hnh ton Section Electrolyte. Thut ton c bn: Phng trnh Mesh c gii quyt nh thut ton Newton-Raphson tnh ton lp vng ngoi, trong khi phng trnh ring cho pha lng vi gi tr K th c tnh ton bng pp lp vng trong. Lp vng trong: nhp cc thng s mu nhit , p sut, phn mol ca cu t pha lng v pha kh. Nhit , p sut v phn mol pha lng th cn cho vic tnh ton thng s v nht cho ca pha lng. Cn phn mol pha kh th cn tnh gi tr K v gia tr K pht sinh c tnh Vng lp ngoi: Mu lp vng ngoi c gii theo thut ton NewtonC 2 cu t + 3 phng trnh v 2 cu t + 3n trn mi a l thuyt. Nhng bin i c lp trn mi a l:a. ln(x), phn mol lngb. ln(y) phn mol khc. a pha lng L1 d. a pha kh V1 e. a nhit T1Nhng phng trnh gii trn mi a l:Cn bng cu t:

Cn bng lng hi:

Cn bng nng lng:

4) Tnh ton thu ng lc hc cho thp chng ctPro/II cha nhng phng php tnh ton cho tc v kch c ca thp a, v cho nhng m hnh thp m c m vi vt liu bt k hay vt liu c cu trc.Thp a c chn nhiu hn thp m ng dng cho nhng trng hp tc ca lng ln. Trong khi thp m thch hp hn thp a trong trng hp chng ct chn khng v cho nhng trng hp c s n mn.Tt c cc tnh ton cho thp a v thp m u yu cu bit nht ng hc. Thng s nht ng hc s l c s ngi dng la chn cc cng c tnh ton nhit ng lc hc ph hp.

5) Tc v kch thc ca thp aThp a bao gm van, thp a l, thp a nhp liu si nh c Pro/II m hnh ho v s dng nh l 1 cng c tnh ton th nghim.Quy trnh c pht biu bi Glitsch dng c tnh nng sut hoc ch dng chy, chnh lch p sut ca van thu lc. i vi thp a l hoc a nhp liu si nh, nng sut c c tnh l 95% v nng sut tng ng l 85% i vi van. Nng sut:Nng sut ca thp a c nh ngha bng yu t nng sut lng hi khng cha lng. th c dng t ti yu t nng sut yu cu da trn khong cch gia cc a v t trng hi.S si bt trn cc a cng c xt n nh l 1 yu t h thng. Bng 5-7 s cho ta thy cc yu t h thng c dng tnh ton chnh xc yu t nng sut hi

thit k thp a ta tnh ton phn trm cc dng tm kch thc ng knh thp, lng hi cn s dng.Lng hi cn s dng c nh ngha nh sau:

Vload : dung lng hi ACFS (actual vapor volumetric flow rate): th tch thc ca hi c lng trcG: t trng hiL: t trng lng gim pi vi van, thp a l, thp a tng si gim p ton b l tng ca gim p trn thp kh v gim p gy ra do lng b nghn trn a

Vi P l gim p tng (trn 1 th tch)Pdry l gim p trn a khPl l gim p do lng trn a gy ra. gim p trn a kh c xc nh da vo th th hin quan h gia gim p do trng lng ca van ti dng hi c tc thp v bnh phng tc ban u ca dng hi c tc cao .a. gim p trn a kh i vi thp a l, phng php Fair c dng xc nh gim p trn a kh theo phng trnh

Vi C l h s chy trnG l tc ban u trn b mt hi i vi thp a tng si, gim p trn a kh c tnh bng phng php Bolles:

Vi : hsh chiu cao tng si H s nh kh K2 trong phng trnh trn l 1 hm s theo t l vng ca vng ng ng.b. gim p ca lng i vi thp a van thy lc, gim p ca lng c tnh theo cng thc sau

Vi L tc ton b dng lng trong thp (gpm)lw chiu di van (inch)hw chiu cao van (inch) i vi thp a l hay thp a tng si gim p ca lng c tnh theo phng trnh

i. Dng cho thp a l:

ii. Dng cho thp a tng si:

Vi : hds tnh ton chiu cao ca cht lng tinh khit a trn cng (ng hc c trng)hs chiu cao ct cht lng gy ra p sut tnhhow chiu cao phn nh trn vanhhg gradient thu ng lc hc chy mngIII. SHORTCUT1) Gii thiu tng quanShortcut c s dng trong tnh ton s b xc nh s bc cn thit i vi 1 s phn tch cho trc. Vic tnh ton da trn quy trnh c in Frenske-Gilliand-Underwood, c lm thch ng x l cc b phn ngng t mt phn hay ton phn. Ta nn s dng m hnh tnh ton nhanh trong giai on u ca flowsheeting hi t cc dng hon lu mt cch d dng hn, bi cc thng s lun tha mn ngay c khi vic nh kch thc c vn . Pro/II iu khin phng php tnh ton chng ct shortcut nhm xc nh trng thi lm vic ca thp nh phn tch cu t, s a cc tiu, t s hi lu ti thiu. Thit b Shortcut gi thit rng lung trung bnh ca cht d bay hi c th c xc nh. Quy trnh Fenske uc dng tnh ton hiu sut v s a cc tiu cn thit. T s hi lu ti thiu uc xc nh bi phng php Underwood. Quy trnh Gilliland uc dng tnh s ia l thuyt yu cu, t l dng hi lu thc t. ng thi phng php ny cng xc nh chc nng ca thit b ngung t v un si c th em li t s hi lu thp nht. Cui cng, quy trnh Kirkbride dng xc nh v tr nhp liu ti u.Shortcut l 1 phng php rt c ch cho nhng ai ln u thit k nhng n thc t. Phng php ny c nhc im l khng hot ng i vi mt s h thng.i vi h thng gn nh khng l tng, shortcut s cho kt qu rt xu hoc khng c kt qu. Trong cc trng hp thp c nhiu cht d bay hi khc nhau shortcut cng s cho kt qu rt xu.Cc ch lm vic ca thit b ngng t c th chn sao cho ph hp: Partial: ngng t 1 phn Mixed: ngng t hn hp Bubble Temperature :ngng t nhit si(chn) Subcooled, Fixed Temperature : nhit qu lnh Subcooled, Fixed Temperature Drop : gim nhit qu lnh2) Phng php tinh toan Quy trnh Fenske:Mi quan h gia tc ho hi gia cu t i v cu t j trn mi a trong thp c th hin qua phng trnh sau

vi x:thnh phn mol trong pha lng y:thnh phn mol trong pha hich s i, j tng ng vi cu t i v jch s N l s a phn ng.i vi nhng thp c bay hi gia cc cu t chnh lch rt nh, ta c th nh ngha bay hi trung bnh. s l ga tr trung bnh ca sn phm nh v sn phm y

S a l thuyt ti thiu c tnh theo cng thc

Quy trnh Underwood:Gi tr ca bay hi ca cc cu t trong dng nhp liu quyt nh cu t no nh cu t no nng. Cu t nh l cu t d bay hi v ngc li.Nu ta t j l bay hi tng i trung bnh ca cu t j

vi j l cu t khaj=1 cu t khaj>1 cu t nh hn cu t khaj