8/3/2019 Ung Dung Chan Khong Trong Chung Cat Dau Khi

1/10

A. TNG QUAN:I. DU M:Du m th l cht lng snh, thng d chy v i khi l cht lng khng linhng. Thnh thong ngi ta cng gp du rn. Du th c mu t vng sang (ikhi du trng) n nu sm v mu en.1. Thnh phn ca du th:

a. Thnh phn nhm hydrocarbon:L thnh phn chnh ca du th, ch yu l bn nhm sau : paraffin, olefin,naphten v aromat.-Parafin: c cu trc tinh th dng phng hoc dng si, nhit nng chy t40:70oC, s nguyn t C trong phn t t 21: 32, phn t lng t 300 : 450,paraffin rn tn ti ch yu trong phn on du bi trn c nhit si t 350 :500oC. Cc iso paraffin cho xng cht lng tt hn, trong khi cc paraffin mchthng c tc dng tiu cc ln tnh cht ca nhin liu ng c t trong. Tuy nhinparafin mch thng vi hm lng carbon khng vt qu gi tr xc nh l thnhphn mong mun cho nhin liu phn lc, diesel v du nhn.-Hydrocarbon khng no: Trong du th him gp olefin v cc hydrocarbon khng nokhc, m n l kt qu ca qu trnh ch bin ph hu cu trc. Chng c hot tnhcao nn d polymer ho, to nha lm gim thi gian tn tr v s dng sn phmdu, l thnh phn khng mong mun cho nhin liu ng c v du bi trn.-Naphten: l thnh phn quan trng ca nhin liu ng c v du nhn, to tnh sdng cao i vi xng t, to cho du nhn c nht t thay i khi nhit thayi.-Aromat: c t trng cao nht, l thnh phn mong mun ca xng nhng li lmgim cht lng ca nhin liu phn lc v diesel v lm xu c tnh chy cachng, c kh nng ho tan cao i vi cc cht hu c, nhng v l do c hi nncng cn hn ch hm lng.b.Thnh phn phi hydrocarbon:-Hp cht lu hunh: thng c mt trong tt c cc du th, thong thng hmlng lu hunh tng t phn on nhit si thp n cao v t cc i trongcn chng ct chn khng, lm gim bn ho hc v kh nng chy hon ton

ca nhin liu ng c, lm cho chng c mi hi, gy n mn ng c.-Nit v hp cht nit:phn ln nm trong cn chng ct, c ng dng lm chtc ch n mn, ph gia cho du bi trn v bitum,tuy nhin chng lm gim hot xc tc trong ch bin du, to nha v lm sm mu sn phm, hm lng caos dn n to kh v cc ho mnh trong qu trinh reforming i vi xng.-Hp cht cha oxy: ch yu dng cc acid hu c, ph bin l acid naphtenic,phenol, keton v ete, thng tp trung phn c nhit si trung bnh v cao cadu th.

2. Cc phn on ca du m:Du m, khi mun ch bin thnh cc sn phm u phi c chia nh thnh tngphn on hp vi cc khong nhit si nht nh. Nhng phn on ny c sdng sn xut mt hoc mt vi loi sn phm nht nh nn chng c mang

tn cc sn phm . Thng thng, du m c chia thnh cc phn on chnhsau y:- Phn on xng, vi khong nhit si di 180oC- Phn on Kerosen, vi khong nhit si t : 180-250oC- Phn on Gas-oil, vi khong nhit si t : 250-350oC- Phn on du nhn (hay cn gi phn on Gasoil nng), vi khong nhit sit 350-500oC- Phn on cn (Gudron), vi khong nhit si > 500oC.Ch : Cc gi tr nhit trn y khng hon ton c nh, chng c th thay i

8/3/2019 Ung Dung Chan Khong Trong Chung Cat Dau Khi

2/10

tu theo mc ch thu nhn cc sn phm khc nhau.Trong cc phn on trn, s phn b cc hp cht hydrocacbon v phi hydrocacbonca du m ni chung khng ng nht, chng thay i rt nhiu khi i t phnon nh sang phn on nng hn, v vy tnh cht ca tng phn on u khcnhau.

3. Du nhn_cn mazt_cn gudron:a. Phn on du nhn (hay phn on gasoil nng) l sn phm chng ct trongchn khng ca phn cn du m, sau khi tch cc phn on xng, kerosene vgasoil. Ba phn on ny thng khng mu, hoc mu nht nn c gi l phnon cc sn phm trng. Phn cn cn li c mu sm n nu en, gi l cnmazut. Mazut c s dng, hoc trc tip lm nhin liu lng cho cc l cngnghip (hin nay th ng dng ny rt t), hoc c chng ct tip tc trong chnkhng ( trnh phn hy do nhit) thu gasoil nng v cn goudron. Phn ongasoil nng c s dng vo cc mc ch sau:- Dng lm nguyn kiu sn xut du nhn.- Dng lm nguyn liu sn xut cc sn phm trng.Khi phn on ny c s dng lm nguyn kiu sn xut du nhn, th phnon c gi l phn on du nhn. Khi phn on c s dng lm nguyn liu sn xut cc sn phm trng phn on c gi l phn on gasoil nng (haygasoil chn khng).

b. Cn mazt:Mazut l phn cn ca qu trnh chng ct kh quyn c nhit si cao hn 350C.Phn cn ny c th em i t hoc lm nguyn liu sn xut du nhn gc. Vimc ch sn xut du nhn gc th ta i em chng ct chn khng, ta thu cphn on c nhit si khc nhau:-Phn on du nhn nh ( LVGO: Light Vacuum Gas Oil ) c nhit si t 300C -350C.-Phn on du nhn trung bnh ( MVGO: Medium Vacuum Gas Oil ) c nhit t350C - 420C.

-Phn on du nhn nng ( HVGO: Heavy Vacuum Gas Oil ) c nhit t 420C -500C.Thnh phn ca cc phn on ny gm nhng nguyn t hydrocacbon c s cacbontrong phn t t C21-40, nhng hydrocacbon trong phn on ny c trng lngphn t ln ( 1000 10000), cu trc phc tp.

c. Cn gudron:Cn gudron l phn cn cn li ca qu trnh chng ct chn khng, c nhit sitrn 500C. Trong phn ny tp trung cc cu t c s nguyn t cacbon t C41 trln, thm ch c c C80, c trng lng phn t ln, c cu trc phc tp. Do ngi ta khng chia thnh phn ca phn on ny theo tng hp cht ring bit mngi ta phn lm ba nhm nh sau:Nhm cht du: chim khong 45 46%.

Nhm cht nha: chim 1% trong cn du m.Nhm asphanten: phn cn li

II. CH BIN DU M:

Mt s qu trnh tiu biu:1. Cc qu trnh vt l:- Tch mui v nc khi du th

8/3/2019 Ung Dung Chan Khong Trong Chung Cat Dau Khi

3/10

- n nh du th- Chng ct p sut kh quyn- Chng ct chn khng2. Cc qu trnh ha hc:- Cracking nhit du th- Nhit phn du th

- Cc ho du nng- Reforming xc tc- Cracking xc tc- X l bng hydro- Ankyl ha- Polymer ha- ng phn ho cc phn on xng

Sn phm du m:B. L THUYT CHNG CT:I. S si ca dung dch:S si ca cht nguyn cht: Mt cht lng s si nhit m ti p sut hibo ho ca n bng p sut mi trng ln mt thong. V d nh nc s si 1000C ti P = 1 atm (760mmHg).Nhit si ca Butanp sut, atm Nhit ,oC1 03.41 364.80 50Ta gi cht c p sut hi bo ho ln, c nht si thp l cht d si. Cht khsi c p sut hi bo ho b, c nhit si cao.Thnh phn pha hi sinh ra khi un si mt dung dch: Pha hi sinh ra khi cht lngnguyn cht si l pha hi n cht. Pha hi sinh ra khi mt dung dch si l mt hnhp ca tt c cc hp phn ca dung dch v c thnh phn ph thuc vo thnhphn ca dung dch lng theo nh lut Konovalov.

nh lut Konovalov: Khi si mt dung dch lng cho ra mt pha hi giu cht d sihn so vi dung dch lng.

II. Nguyn l ca qu trnh chng ctChng ct l qu trnh tch mt dung dch bng cch un si n, ri ngng t hibay ra c 2 phn: Phn nh l distillat c nhit si thp, cha nhiu cht dsi, cn phn nng cn li l cn chng ct (redue).

Nh vy, php chng ct c th thu c Distillat c thnh phn mong mun bngcch chng ct nhiu ln.Nhng chng ct nhiu ln nh vy rt phin phc, tn thi gian m khng kinh t. khc phc nhc im ny ta dng h thng chng ct c ct chng ct. Ct

chng ct c s a l thuyt cng ln, th c kh nng cho mt distillat c thnhphn khc cng nhiu so vi dung dch trong bnh un, tc l distillat rt giu chtd bay hi. Dng ct chng ct c nhiu a l thuyt c th thu c distillat l chtd bay hi gn nh tinh khit.

III. C s l thuyt chng ct du mNhm phn tch du th thnh cc phn on thch hp da vo nht si ca cccu t v khng lm phn hu chng.1. Chng ct n gin

8/3/2019 Ung Dung Chan Khong Trong Chung Cat Dau Khi

4/10

a. Chng ct bay hi dn dn: Ch yu dng trong phng th nghim xc nhng cong chng ct Enghen. Chng ct bay hi mt ln: Cho php nhn cphn chng ct ln hn so vi bay hi mt ln.Chng ct bay hi nhiu ln: Cho php qu trnh tch cc phn on theo mongmun.2. Chng ct phc tp

a. Chng ct c hi lu: nng cao kh nng phn chia hn hp lng, ngi ta tinhnh cho hi lu mt phn sn phm nh. Nh s tip xc thm my ln gia phalng (hi lu) v pha hi trong thp c lm giu thm cu t nh nh m phn chia cao hn.b. Chng ct c tinh luyn: Da vo qu trnh trao i cht nhiu ln gia pha lngv hi nh vo cc a hay m. Chng ct s c phn chia cao hn nu kt hpvi hi lu

S tip xc gia dng lng v hi trong thp chng ct

c. Chng ct chn khng & chng ct vi hi nc: bn nhit cc cu t trongdu ph thuc ch yu vo nhit v thi gian lu. i vi cc phn on c nhit si cao, ngi ta cn trnh s phn hu chng (gim nht, bn oxy ho)bng cch hn ch nhit (320o- 420oC) chng ct. Nu nhit si cao hn nhit phn hu chng ta dng chng ct chn khng hay chng ct hi nc. Hi nclm gim p sut hi ring phn lm chng si nhit thp hn.

IV. a chng ct (Tray)Trong cng ngh du kh, chng ct nhng lng khng l (hng triu tn/nm).Ngi ta dng nhng thit b chng ct khng l, hot ng lin tc.Hi nguyn liu s bay ln nh thp v phn lng s chy xung phn di thp. Stip xc gia hai dng ny c thc hin mt cch c bit nh cc a.Ti cc a xy ra qu trnh trao i nhit gia dng hi v dng lng. ng thi tiy cng xy ra qu trnh trao i cht, phn nh trong pha lng bay hi theo pha

hi, phn nng trong pha hi ngng t theo dng lng.Nh vy, khi dng hi ln n nh th rt giu cu t nh, cn dng lng i xungy li giu cu t nng hn.C rt nhiu dng a khc nhau c s dng tu vo loi nguyn liu. Nhng mcch chung nhm m bo s tip xc gia pha lng v pha hi phi ln qu trnhphn tch hiu qu.Hin nay, s dng ch yu cc dng a sau: a nhiu l (Sieve Trays) a chp (BubbleCap Trays) a ng khi (Chimmey Trays) a Van (Valve Trays)

V. S Stripping

i vi chng ct du th, dng trch ngang lun c ln sn phm nh. loi b cc cu t nh ny, ngi ta thc hin qu trnh ti ho hi ring phn ccphn nh. Qu trnh ny gi l qu trnh stripping.Qu trnh ny c thc hin trong nhng ct nh t 4-10 a, t bn cnh thpchng ct kh quyn v thng dng hi nc trc tip.Ngoi ra c th stripping bng nhit (phn on Kerozen).

VI. S hi lu (Relux)Nhm to ra dng lng c nhit thp i t nh thp xung y thp trao i

8/3/2019 Ung Dung Chan Khong Trong Chung Cat Dau Khi

5/10

nhit vi dng hi. T lm cho qu trnh trao i cht tch phn on c trit v thu c cht lng distillat mong mun.T l dng hon lu ph thuc vo nhiu yu t, trong yu t kinh t l bi tonquyt nh.Khi t l hon lu tng, s mm gim nhng ng knh thp tng ln. Ch yu c 3dng sau:

Hi lu nng: S dng dng hi lu trng thi lng si. Hi lu lnh: Nhit dng hi lu di im lng-si. Hi lu vng: Ly cc sn phm cc mm di hi lu ln cc mm trn sau khi lm lnh.

C. NG DNG K THUT CHN KHNG TRONG CHNG CT DU M:

I. CHN KHNG V K THUT CHN KHNG:1. Chn khng:Chn khng, theo l thuyt c in l trng thi khng gian khng cha vt cht. Vvy, vng khng gian ny c th tch khc khng nhng khi lng v nng lngu bng khng. iu c ngha l p sut tuyt i trong vng khng gian nycng bng khng. Chn khng nh th c gi l chn khng tuyt i.Tuy nhin, trong thc t khng th tn ti vng chn khng tuyt i nh vy c.Khoa hc vt l l thuyt cng chng minh rng khng tn ti vng chn khngny do vi phm cc nguyn l ca vt l vi m v thng ging lng t. Cn v mtk thut, ngi ta nh ngha chn khng l vng khng gian c mt vt chtthp hn so vi mt vt cht trong khng kh, hay ni cch khc, l vngkhng gian c p sut tuyt i thp hn p sut kh quyn tiu chun (p 100 Pa)- Chn khng trung bnh (100 Pa > p > 0,1 Pa)- Chn khng su (0,1 Pa > p > 10-5 Pa)- Chn khng rt su ( p < 10-5 Pa).

2.K thut chn khng:Trong mt s quy trnh cng ngh, ta khng th s dng quy trnh di p sutthng c m phi s dng p sut chn khng trong h thng. V d nh mt sthit b c c cc dung dch d bin tnh v nhit ( nh nc ng, nc p tricy), thit b chng ct chn khng trong chng ct phn on du m. c imchung ca cc quy trnh ny l do ta khng th cho hot ng di p sut khquyn c l v cht tan s b phn hu, b bin tnh, hoc b bin i thnh ccdng hp cht ho hc khng mong mun di tc dng ca nhit. Do , s dngp sut chn khng trong h thng s gip ta gim nhit , cho php ta thu csn phm mong mun.

III. NG DNG CHN KHNG TRONG CHNG CT DU TH:

Sau khi chng ct du di p sut kh quyn nhit 350 370oC, chng cttip cn cn li cn chn iu kin loi tr kh nng cracking v to iu kin thuc nhiu phn ct nht. Ph thuc vo nguyn liu t cn chng ct kh quyn(mazut) c th thu c distilat du nhn cho cm sn xut du nhn, hoc gasoilchn khng - l nguyn liu cho cracking xc tc. Phng php ph bin nht tch cc phn on ra khi mazut l chng ct trong chn khng. Chn khng hnhit si ca hydrocarbon v cho php ly c distilat c nhit si 500oC nhit 410 420oC. Tt nhin khi gia nhit cn du n 420oC th s din racracking mt s hydrocarbon, nhng nu distilat nhn c sau c ch bin th

8/3/2019 Ung Dung Chan Khong Trong Chung Cat Dau Khi

6/10

cp th s hin din ca cc hydrocarbon khng no khng c nh hng ng k. iu ch distilat du nhn th phn hy cn phi t nht bng cch tng hi nc,gim chnh lch p sut trong thp chn khng. Nhit si ca hydrocarbon gimmnh nht khi p sut d thp hn 50 mmHg. Do cn ng dng chn khng sunht m phng php cho php.Ngoi ra, tng hiu sut distilat t mazut a vo thp chn khng hi nc qu

nhit hoc chng ct cn chn khng (gudron) vi tc nhn bay hi (phn onligroin- kerosen).Chn khng to thnh nh thit b ngng t kh p hoc my bm chn khng (bmpiston, bm rotary, bm phun hoc bm tia) mc ni tip vi nhau.

1. Thit b to chn khng:Chn khng trong thit b c to thnh bng cch ngng t kh trong khng giankn v ht kh v hi khng ngng t ra bng thit b tng ng. Trong phn ny giithiu cc thit b ngng t b mt, my bm chn khng, thit b ngng t kh p vmy bm phun (ejector). My bm chn khng dng bm kh, nn v x.

a) Thit b ngng t b mt:Trong s d chng ct chn khng cng sut cao chn khng trong thp K-10( H.6.3) c to ra bng thit b ngng t b mt v bm phun vi thit b ngngt b mt trung gian. Hn hp hi nc, hydrosunfua v kh phn hy i ra t thpK-10 trc tin i vo khng gian gia cc ng thit b ngng t b mt dng cnh, kt cu ca chng c trnh by trong hnh 6.9.Trong ng ca thit b ngng t b mt theo h thng 8 dng nc lnh chy t diln trn. Nh lm lnh v ngng t hi trong khng gian gia cc ng ca thit bngng t b mt th tch pha hi gim mnh v to thnh chn khng trong thp.

b) My bm chn khng:C my bm chn khng kh v t, piston v quay. My bm kh ch dng bmkh kh, cn bm t- bm kh cha cht lng. My bm chn khng piston kh c

nng sut 160-200 m3/pht v to chn khng n 30mmHg.My bm chn khng quay c trang b bnh hot ng gn cc gu bt ng tlch tm trong thn my bm. My bm c rt y nc hoc cht lng khngchy v khng n mn cc chi tit my khc n mt mc, sao cho phn cui cacc gu khi quay lun nm trong cht lng. Khi bnh xe quay nhanh nc (chtlng) vng vo thnh, to thnh vng nc cn bng. Gia cc gu v vng ny ditc dng ca lc tm sai ca bnh xe to thnh cc c th tch khng ng u-di l ln, trn - nh. Khi piston hot ng nc c lp y. na vngquay u ca van cc to ln v cc khe ny kh c ht. Trong na vng quay th2 cc xp xung, b nn li v x kh qua l chuyn dng. Chiu su chn khngph thuc vo nhit ca cht lng lm vic. Do , nc c np vi nhit cng thp cng tt, cht lng c lm lnh trong my lnh chuyn dng.My bm chn khng quay nn c dng khi kh nn khng cha hydrosunfua. u

im ca my bm ny l c th ni chng trc tip vi ng c in, khin chochng gn v cht ch. My bm chn khng quay hiu RMK nng sut 720-1800m3/h to thnh chn khng khong 720mmHg.

c) Thit b ngng t kh pThit b ngng t kh p gm ng 3 c chiu cao 12m, trong cc dng kh v ncchuyn ng gp nhau; hi nc ngng t v cng vi nc qua ca van thy lcchy vo b cha hoc thi vo knh. Van thu lc c to thnh nh sau: ui cang 3 ngp trong lp nc trong b 4. Khng kh v kh khng ngng t c ht

8/3/2019 Ung Dung Chan Khong Trong Chung Cat Dau Khi

7/10

bng my bm chn khng hoc bm tia nc.

d) Bm phun tiaHi hot ng phun ra t vi phun 1 vi tc siu m. Nh s trn ri ca tia hichuyn ng xoy vi cc ht khng kh \, trong bung ht 2 din ra s ht khkhng ngng t v cun chng vo ng thtt bung trn 3 trn hon ton hi

vi kh. Bung trn 3 kt thc bng hng hnh tr. Tr hong dng hi trn vi khc ht i vo bung khuch tn 4 chuyn ng nng ca dng thnh cng khihn hp ri khi thit b

e) H thit b ngng t kh p - bm phun.

Trong h ny hi thot ra t nh thp chn khng, ngng t ngay lp tc trong thitb ngng t kh p v sau c ht bng my bm chn khng (thng bm phunhi). p sut d trong thit b ngng t kh p ph thuc vo nhit nc thi,nhng khng thp hn p sut hi nc bo ha nhit no . Nc t thit bngng t kh p b nhim sn phm du v hp cht lu hunh (thng 5,5% so vimazut). V vy gim dng nc nhim bn trong nh my nc thi c s dngli. Tuy nhin, khi nhit nc vo thit b ngng t kh p s tng i chtv phi trang b thm ph kin cho h cp nc.Trong s to chn khng bng h thit b ngng t kh p - bm phun. Sn phmdu ngng t trong thit b ngng t khng ha long bng nc lnh, nh n ddng tch ra khi condensat, c thu gom vo b lng v ging kh p.f) H bm phun - thit b ngng t kh p.Trong s ny hi t trn thp chn khng a trc tip vo bm phun, cn suca chn khng khng ph thuc vo nhit ca nc thot ra t thit b ngng tkh p. Nh c th to chn khng su hn (p sut d t 5 10 mmHg). su chn khng ph thuc vo i p ti ca ra ca bm phun, v vy to chnkhng su cn mc ni tip vi bm phun.

2. c im chng ct trong thp chn khng

c im chng ct trong thp chn khng tng t nh trong thp chng ct khquyn. Tuy nhin n cng c mt s c im ring lin quan vi p sut d trongthp thp, iu kin nung nng nhin liu c thnh phn phn on nng. Trongthp chn khng cn to iu kin ct c nhiu nht v phn hy t nht. lm c iu ny cn s dng thit b to chn khng c c p sut chnkhng thp nht trong h. gim thi gian lu ca mazut trong l nung v gimtr lc nn s dng l nung hai chiu, a hi nc vo ng xon ca l, gim thiukhong cch gia ca nhp liu vo thp v ca ra khi l nung, tng ng knhng dn nguyn liu, gim thiu cc ch un gc, dng ch S.Cu to ca thp chn khng khc vi thp chng ct kh quyn nhm gim thigian lu ca cn trong thp trnh phn hy n di tc dng ca nhit cao. Dolu lng cc dng hi trong thp chn khng ln, nn ng knh ca cc thp nyln hn nhiu so vi thp ct kh quyn (8 12 m). Do s phn b ca cht lng v

bt si khng ng nht nn hiu qu ca mm khng cao. phn b cht lngng u trn cc mm nn s dng cu trc mm c bit (mm li, van (xupap)v sng).

3. S cng ngh cm chng ct chn khng

S nguyn tc cm chng ct chn khng trnh by trong hnh 16. Mazut t dithp K-2 c my bm H-21 (khng v trong s ) bm vo ng xon ca l nungL-3 v sau khi nung nng n 400 410oC c dn vo thp chng ct chn

8/3/2019 Ung Dung Chan Khong Trong Chung Cat Dau Khi

8/10

khng K-10. gim s phn hy ca mazut khi nung nng nhit cao v tocc trong cc ng l nung v tng phn ct, thm hi nc qu nhit vo tng dngchy qua l nung ti ca vo thp K-1. nh thp chng ct chn khng K-10 gip sut khng qu 50 mmHg. Kh sinh ra khi phn hy mazut cng hi nc cdn sang thit b ngng t T-35, trong hi nc ngng t, cn kh c ht bngmy bm chn khng - phun ba cp H-1. Phn ngng t t T-35 c a vo b

cha E-22, t vo b cha B, nc t c thi ra cn sn phn du tch ttrong b lng c my bm H-40 bm vo ca np ca my bm nguyn liu.T mm 15 ca thp chn khng K-10 dng hi lu trn c my bm H-24 ht rav bm qua cc thit b trao i nhit T-25, thit b ngng t bng khng kh T-25a,my lnh T-28 v vi nhit 50oC c a tr li mm 18 ca thp K-10. Phnon c nhit si di 350oC d c my bm H-24 bm vo thp K-2 hoc vong ng nhin liu diesel. Cng c th a dng hi lu nng vo mm 14 nhmy bm H-24.T mm 9 trch phn on 350 500oC ra di dng sn phm trung gian, sau n c my bm H-25 bm qua thit b trao i nhit T-16 (dng nng), sau lng phn on 350 500oC cn thit quay tr li thp nh dng hi lu sau khi qua my lm lnh T-30, phn d qua thit b trao i nhit T-1 v ly ra ngoi.T mm th 9 ca thp K-10 dng hi lu di c my bm H-26 bm vo thit btrao i nhit T-18 v thit b lm lnh T-31, trong n c lm lnh n 170oCv tr v mm s 6, cn phn d quay tr li thp chng ct kh quyn K-2. T bmH-25 v H-26 hai dng nng tr li tng ng ti mm th 8 v th 4.T y thp K-10 gudron (nha ng) c my bm H-27 bm qua thit b traoi nhit T-4, T-3, T-34, my lnh T-24 v vi nhit khng qu 100oC c avo b cha.

4. Ch cng nghS cng ngh cm chng ct chn khng c thit k vi mc ch nhn cphn on 350500oC (nguyn liu cho cracking xc tc) v nha ng (gudron).Thp chn khng c trang b mm van. Tt c cc mm u dng hai dng. Tngs mm l 18.Trn mm np liu v di mm sut dng hi lu gia c lp t li

chn.5. Cc sn phm thu c khi chng ct du th trong chn khng:Ch bin mazut trong chn khng thu c cc distilat du nhn c nhit si, nht v cc tnh cht khc khc nhau, cn ca qu trnh ny l semigudron hocgudron. Cc s chng ct chn khng c chia thnh nhm nhin liu v dunhn. Trong nhm s nhin liu t mazut thu phn on rng c nhit si n5500C gi l gasoil chn khng, l nguyn liu cho cracking xc tc hochydrocracking.Trong nhm cng ngh th 2 thu c phn on du nhn, sau khich bin ( x l bng hydro, lm sch la chn, loi parafin bng xc tc hoc loiparafin nhit thp trong dung mi, lm sch tip xc) c th thu c cc dunhn gc khc nhau.

Trong cc nh my chng ct chn khng nguyn liu mazut hin i c 2 loi s cng ngh: chng ct bay hi 1 bc tt c cc phn on v phn tch n trong 1thp chn khng v chng ct mazut bay hi hai bc v phn tch phn on chngct trong 2 thp chn khng. thu c gasoil chn khng vi khong si 350-5000C lm nguyn liu chocracking xc tc hoc hydrocracking th chng ct 1 bc t yu cu. Nu cn phithu c nguyn liu sn xut du nhn th tt hn nn chn h thng chng ct

8/3/2019 Ung Dung Chan Khong Trong Chung Cat Dau Khi

9/10

chn khng 2 thp. Trong thp th nht tch c phn on du nhn rng, trongthp th hai - chng ct tip n thnh cc phn on du nhn hp.Trong hnh v 6.8 dn ra s nguyn tc chng ct chn khng mazut hai bc nhn phn on du nhn. Mazut nng vi nhit 310-3150C t thp chng ct khquyn c my bm bm vo l nung gia nhit n 410-4200C v a vo thpchng ct chn khng th nht K-4. Trong thp K-4 din ra phn tch phn on

chn khng rng ra khi cn nng l gudron. ct phn on chn khng tt hnv gim nhit bay hi, a vo thp K-4 hi nc qu nhit vi khi lng 1-1.5% so vi nguyn liu. Nu phn on chn khng rng c s dng lm nguynliu cho cm cracking xc tc hoc hydrocracking, th n c ly ra t mm th 6v th 7 ca thp th nht, cho nhit trong trao i nhit v a vo s chbin tip. Ty thuc vo kh nng ca s , phn on chn khng rng c nhit si trong khong 350-5200C.Khi ch bin phn on chn khng rng vi mc ch thu cc du nhn khc nhaun c gia nhit b sung bng nhit ca gudron trong trao i nhit vi gudron vi vo thp chn khng th hai tinh ct thnh nhng phn on hp hn. Nhitlng thiu c ly t di thp K-5 di dng tia nng nh tun hon distilat dunhn nng c ly ra c nhit si 420-490 hoc 420-5000C qua mt phn ngca l nung. a vo thp K-5 hi qu nhit.Cht lng sn phm du thu c trong thp chng ct chn khng th nht nhsau:Phn on 350 n 5000C:Hm lng nha, % k.l, khng qu 12Bay hi, % t.t.n 4800C, khng thp hn 96n 3500C, khng cao hn 20Nha ng (phn on > 5000C):Nhit chp chy, 0C, khng thp hn 200 nht tng i 800C 80-150Bay hi n 5000C, % t.t, khng qu 96T thp th hai thu cc phn on 350-4200C v 420-5000C. Hi lu cho thp thc

hin bng cch ly mt phn ct trch ngang trn t thp K-4 v K-5, lm lnh chngtrong trao i nhit v thit b lm lnh, tip theo a phn ct lnh ln mm trn,Nhit lng d c ly ra bng dng hi lu tun hon.Hi v kh phn hy khng ngng t ly ra t thp K-4 v K-5 ht vo thit b tochn khng. Vi mc ch khng to khi, mui trong khu vc nh my, kh phnhy v hydrosulfua sau bc cui cng ca bm tia hi a vo l nung t.D. MT S CNG THC TNH TON:I. Tnh thit b ngng t kh p ( thit b ngng t baromet)1. Chi ph nc lm lnh cho thit b ngng t:

Trong : Gn ( kg/gi): lu lng nc lm lnhGhn (kg/gi): lu lng hi ncI (kcal/kg): entanpy ca hi nc i vo thit b ngng t kh p

C = 1kcal/(kg.): nhit dung ring ca nct1 (0C) : nhit vo ca nct2 (0C) : nhit ra ca nc.t3 (0C) : nhit vo ca hi v kht4 (0C) : nhit ca kh ht nh thit b ngng t, t4 t1Gg (kg/gi): lng kh phn hu ( c th chn bng 0,1% so vi nguyn liu)Gkk (kg/gi): lng khng kh b ht voCkk (kcal /(kg.K)): nhit dung ca khng kh.Lng khng kh b ht vo xc nh bi:

8/3/2019 Ung Dung Chan Khong Trong Chung Cat Dau Khi

10/10

Vi: = 1,293 kg/m3V (m3): th tch thp(mmHg): gim chn khng cho php trong thit b ( t 10 n 12 mmHg)t: nhit trong thp sau khi th kn (c th chn khong 250C).Nhit khng kh v hi phn hu ht vo t4 c th xc nh theo biu thc sau:

t4 = t1 + 0,1(t2 t1) + 4

2. ng knh ng kh p: xc nh t tit din ng cn thit khi bit th tch tngca nc v cht ngng t ri khi thit b ngng t, vi tc dng ( c th chnt thc t trong khong 0,5 n 2m/s).3. Chiu cao ng kh p:c xc nh theo cng thc: H = H0 + h1 + hH0 (m): chiu cao ct nc trong ng kh p trng thi cn bng tnh vi chnhlch gia p sut kh quyn vi p sut trong thit b ngng t, c tnh bi cngthc:

h1 (m): chiu cao d tr ( thng thng hay chn l 0,5m)h (m) : chiu cao ng vi tn tht p sut.4. ng knh thit b ngng t kh p: xc nh t vn tc kh v hi, lu lng. Tuynhin, khi tnh ta chn cng sut cao gp 1,5 ln thc t v cc ngn chim 70% titdin ca thit b ngng t.

II. Tnh thit b ngng t b mt:1. Lng nhit ti c Q (kcal/gi):- Cho thit b ngng t - lm lnh

- Cho thit b lm lnh:

Trong : Gd, Ghn, Gn (kg/gi): lu lng du th, hi nc v nc

(kcal/kg): entanpy ca hi sn phm du nhit vo t1(kcal/kg): entanpy ca sn phm du lng nhit ra t2Chn: nhit dung ring ca hi nc, khong 0,48 kcal/(kg.K)t3(0C) : nhit ngng t ca hi nct4, t5 (0C): nhit u v cui ca hi ncrhn (kcal/kg): nhit ngng t ca hi ncCn (kcal/(kg.K)): nhit dung ring ca nc.Ch : lng nhit Q tnh cho thit b lm lnh-ngng t khc vi thit b lm lnh ch tnh c lng nhit ngng t do hi nc to ra.2. Lng nc cn thit cho lm lnh:

3. B mt lm lnh:, m2

i vi loi thit b ny, h s truyn nhit trong khong 70-100 kcal/(m3.h.K).

III. Tnh thit b bm phun hi ( bm ejector dng hi)Ta la chn my bm ejector ph hp vi khi lng kh phn hy v khng kh htqua thit b khng kn v do hi nc lm lnh sinh ra.