do_an_hoa_cong 2011

n Ha cng

H Cng Nghip H Ni Khoa CN Ha

B Cng Thng Trng H Cng nghip H Ni

Cng ho x hi ch ngha Vit Nam c lp - T do - Hnh phc

n mn hc Qu trnh thit bS : H v tn HS-SV : Phm Th M Hnh Lp : C-H Ha 5 Khoa : Cng ngh Ha Gio vin hng dn : thy Nguyn Tun Anh Kha: 4

Ni dungThit k h thng chng luyn lin tc loi thp m phn tch hn hp Axeton nc. Cc s liu ban u: Hn hp u F=4200Kg/h. XF=40% khi lng XP=98% khi lng Xw=3% khi lng

Tn bn v T

Kh giy

S lng

V dy chuyn sn xut V thp chng luyn

A4 A0Phn thuyt minh

01 01

Sv: Phm Th M Hnh Lp LTC-H Ha 5k4

1

n Ha cng


MC LCLI M UChng I: GII THIU CHUNG:.................................................................. 5 1.1: L THUYT V CHNG LUYN: ................................................... 5 1.1.1: Phng php chng luyn: ............................................................... 5 1.1.2. Thit b chng luyn: ........................................................................ 5 1.2.GII THIU V HN HP CHNG LUYN:................................. 6 1.2.1.Axetone: ............................................................................................. 6 1.2.2. Nc (H2O):...................................................................................... 8 1.3. DY CHUYN SN XUT: ................................................................ 9 1.3.1. S cng ngh:............................................................................... 9 1.3.2. Thuyt minh dy chuyn sn xut: ................................................... 10 Chng 2: TNH TON THIT B CHNH: ................................................ 11 2.1 TNH TON CN BNG VT LIU CHO TON THIT B: ...... 11 2.1.1. Thng s ban u: ............................................................................. 11 2.1.2. Cn bng vt liu: ............................................................................. 12 2.2. XC NH S A L THUYT: ..................................................... 14 2.2.1. Phng trnh ng nng lm vic ca thp: .............................. 14 2.2.2. Xc nh s bc thay i nng :.................................................... 15 2.3. NG KNH THP CHNG: ......................................................... 27 2.3.1. Lng hi trung bnh i trong thp: ................................................. 27 2.3.2. Khi lng ring trung bnh trong thp: ........................................... 31 2.3.4. ng knh thp chng luyn: ......................................................... 37 2.4. CHIU CAO THP CHNG LUYN: .............................................. 38 2.4.1. Chiu cao ca 1 n v chuyn khi:................................................ 38 2.4.2. S n v chuyn khi: ..................................................................... 39 2.4.3. Tnh m: .............................................................................................. 50 2.4.4. Xc nh chiu cao thp:................................................................... 51 2.4.5. Chiu cao ton thp:.......................................................................... 51


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n Ha cng


2.5. TR LC CA THP M: .............................................................. 52 2.5.1. Tr lc ca on chng: ................................................................... 53 2.5.2. Tr lc on luyn: ........................................................................... 54 2.6. CN BNG VT LIU: ....................................................................... 55 Chng 3: TNH TON C KH V LA CHN: .................................... 62 3.1. TNH TON THN THP: ................................................................. 62 3.1.1. Vt liu lm thp: .............................................................................. 62 3.1.2. Chiu dy thn thp: ......................................................................... 67 3.2. Y V NP THIT B: ..................................................................... 68 3.2.1. Chiu dy np thit b: ...................................................................... 66 3.2.2. Chiu dy y thit b: ...................................................................... 67 3.3. NG KNH NG DN:.................................................................. 68 3.3.1. ng knh ng dn sn phm nh: ................................................ 68 3.3.2. ng knh ng dn hn hp u: ................................................... 70 3.3.3. ng knh sn phm y: ............................................................... 70 3.4. TRA BCH GHP: ................................................................................ 71 3.5. LI M, DM M:........................................................ 73 3.5.1. a phn phi cht lng: ................................................................... 73 3.5.2. Li m:..................................................................................... 73 3.5.3. Dm m:..................................................................................... 73 3.6. GI V TAI TREO:....................................................................... 77 Chng 4: TNH TON THIT B PH: ..................................................... 79 4.1. THIT B GIA NHIT HN HP U:........................................... 79 4.2. THNG CAO V: .................................................................................. 86 4.3. BM: ....................................................................................................... 96 KT LUN: ....................................................................................................... 99 TI LIU THAM KHO: ............................................................................... 100


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n Ha cng


LI M UNgy nay cng vi s pht trin ca khoa hc k thut, nn cng nghip mang li cho con ngi nhng li ch v cng to ln v vt cht v tinh thn. nng cao i sng nhn dn, ha nhp chung vi s pht trin chung ca cc nc trong khu vc cng nh trn th gii ng v Nh nc ta ra mc tiu cng nghip ha v hin i ha t nc. Trong tin trnh cng nghip ha hin i ha t nc nhng ngnh mi nhn nh cng ngh thng tin, cng ngh sinh hc, cng ngh in t t ng hacng ngh ha gi vai tr quan trng trong vic sn xut cc sn phm phc v cho nn kinh t quc dn, to tin cho nhiu ngnh khc pht trin. Khi kinh t pht trin th nhu cu ca con ngi ngy cng tng. Do vy cc sn phm cng i hi cao hn, a dng hn, phong ph hn, theo cng ngh sn xut cng phi nng cao. Trong cng ngh ha h c ni chung vic s dng ha cht c tinh khit cao l yu t cn bn to ra sn phm c cht lng cao. C nhiu phng php khc nhau lm tng nng , tinh khit nh: chng ct, c c, trch ly. Ty vo tnh cht ca h m ta la chn phng php thch hp.Vi nhim v tch hn hp hai cu t axeton-nc c axeton nng cao th chng ct l phng php hu hiu nht. Tp n ny bao gm 4 chng: 1: Gii thiu chung 2: Tnh ton thit b chnh 3: Thit b ph 4: Tnh ton c kh v la chn 5: Bn v chi tit thp chng luyn loi thp m


4

n Ha cng


CHNG 1 GII THIU CHUNG 1.1 L THUYT V CHNG LUYN 1.1.1. Phng php chng luyn Chng l phng php dng tch cc hn hp kh lng thnh cc cu t ring bit da vo nhit si khc nhau ca cc cu t trong hn hp. Khi chng ta thu c nhiu sn phm v thng c bao nhiu cu t th c by nhiu sn phm. Phng php chng luyn ny l mt qu trnh trong hn hp c bc hi v ngng t nhiu ln. Kt qu cui cng ta thu c nh thp l mt hn hp gm cc cu t d bay hi c nng t yu cu. Phng php chng luyn cho hiu sut cao nn n c s dng nhiu trong thc t. Cc phng php chng ct bao gm: Chng n gin . Chng bng hi nc trc tip . Chng bng hi nc gin tip Chng chn khng Chng p sut thp Chng p sut cao

Trong trng hp ny vi yu cu axeton c tinh khit cao khi s dng, cng vi hn hp axeton- nc khng c im ng ph nn chn phng php chng lin tc l hiu qu nht.

1.1.2 Thit b chng luyn Trong sn xut thng s dng rt nhiu loi thp khc nhau nhng chng thng c mt yu cu c bn l b mt tip xc pha ln. Thp chng ct phong ph v kch c v ng dng, cc thp ln thng c s dng trong cng ngh ha lc du. ng knh thp ph thuc vo lng pha lng v pha kh, tinh khit ca sn phm. Cc loi thp thng s dng nh: Thp m5


n Ha cng


-

Thp a l c ng chy truyn Thp a l khng c ng chy truyn Thp chp

Mi loi thp chng li c cu to ring, u nhc im khc nhau v vy ta phi chn loi thp no ph hp vi hn hp cu t cn chng v tnh ton thit b ph hp vi yu cu. 1.2 GII THIU V HN HP CHNG LUYN 1.2.1 Axeton CH3COCH3 a. Tnh cht vt l Axeton l cht lng khng mu, d bay hi, c mi c trng v tan v hn trong nc. Khi lng phn t M = 58 Nhit nng chy: -95.3oC Nhit si: 56.5 oC b. Tnh cht ha hc Phn ng kh vi H2 Axeton c phn ng kh vi H2 ging Andehit: CH3-CO-CH3 + H2 Phn ng oxi ha: Axeton khng b oxi ha bi dung dch bc nitrat trong amoniac (khng trng gng), khng kh ng (II) hidroxit, m b oxi ha bi cc cht oxi ha mnh nh: KMnO4, K2Cr2O7, vi H2SO4 c. CH3COCH3 + 4[O] CH3COOH + CO2 + H2O CH3-CH(OH)-CH3

Phn ng cng to ru bc 2


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n Ha cng


c. iu ch Oxi ha ru bc 2:

Theo phng php Piria:nhit phn mui canxi ca axit cacboxilic (CH3COO)2Ca CH3COCH3 + CaCO3

Thy phn 2,2-iclo propan:

i t hp cht c Magi: CH3MgCl + CH3COCl d. ng dng Sn xut sn v nha resin Aceton l dung mi ho tan tt nitrocellulose, cellulose acetate, cellulose ether, c dng lm gim nht ca sn ccha nha ny. c bit, nthch hp sn xut sn mau kh v c tc bay hi cao. Ngoi ra cng dng Acetone trong sn xut sn c hm lng cht rn cao. Dc v m phm Axeton dng lm cht kh nc trong sn xut thuc v trong cng nghip m phm, sn v ra mng tay. Nn kh axetilenSv: Phm Th M Hnh Lp LTC-H Ha 5k47

CH3COCH3 + MgCl

n Ha cng


Axetilen l mt cht kh cng nghip quan trng nhng khng th nn mt cch hiu qu m bo trong c bnh hnh tr m khng c nguy c b n. Axeton c th ha tan lng ln kh Axetilen (khong 300 ln so vi th tch thc ca n) do axetilen c cha trong bnh kn cng vi axeton. Ngoi ra axeton cn c s dng lm cht ty ra v kh nc cho cc thnh phn in t, dung mi trong ngnh sn xut cao su 1.2.2. Nc H2O a. Tnh cht vt l Nc l mt hp cht ha hc ca oxy v hidro, c cng thc ha hcl H2O. Vi cc tnh cht l ha c bit (v d nh tnh lng cc, lin kthiro v tnh bt thng ca khi lng ring) nc l mt cht rt quantrng trong nhiu ngnh khoa hc v trong i sng; 70% din tch ca Trit c nc che ph nhng ch 0,3% tng lng nc trn Tri t nmtrong cc ngun c th khai thc dng lm nc ung. Trong iu kin bnh thng nc l cht lng khng mu, khng mi, khng v, nhng khi nc dy s c mu xanh nht. Khi ha rn n c th tn ti 5 dng tinh th khc nhau Khi lng phn t: 18g/mol Khi lng ring d4oC: 1g/cm3 Nhit nng chy: 0oC Nhit si: 100oC b. Tnh cht ha hc V mt ha hc, nc l mt cht lng tnh, c th phn ng nh 1 axit hay baz. pH 7 hm lng OH- cn bng vi hm lng H3O+ Phn ng vi axit mnh: H2O + HCl Phn ng vi amoniac: H2O + NH3 ng dng NH4+ + OHH3O + Cl-


8

n Ha cng


1.3 DY CHUYN SN XUT 1.3.1. S cng ngh sn xut

Hnh 1.1: S cng ngh chng luyn

Ch thch:1: Thng cao v 2: B cha dung dch u 3: Thit b gia nhit u 4: Lu lng k 5: Thp chng luyn 6: Thit b ngng t 7: Thit b lm lnh 8: B cha sn phm nh 9: B cha sn phm y 10: Thit b gia nhit y 11: Thit b tho nc 12: Bm


9

n Ha cng


1.3.2. Thuyt minh s Nguyn liu u c cha trong thng cha (2) v c bm (12) bm ln thng cao v (1) .Mc cht lng cao nht c khng ch bi ng chy trn tr li b cha dung dch u (2). Hn hp u t thng cao v t chy xung thit b un si hn hp u (3). Lu lng c khng ch bng cch iu chnh h thng van v lu lng k (4) hi nc bo ha t ni hi vo un si hn hp u n nhit si sau khi t ti nhit si hn hp ny c a vo a tip liu ca thp chng luyn (5) loi m.Trong thp hi i t di ln tip xc trc tip vi lng chy t trn xung, ti y xy ra qu trnh bc hi v ngng t nhiu ln.Theo chiu cao ca thp, cng ln cao th nhit cng thp nn khi hi i qua cc tng m t di ln, cu t c nhit si cao s ngng t. Qu trnh tip xc lng hi trong thp din ra lin tc lm cho trong pha hi cng giu cu t d bay hi.Cui cng trn nh thp ta s thu c hu ht l cu t d bay hi (c th y l Axeton) v mt phn cu t kh bay hi (Nc). Hn hp hi ny c a vo thit b ngng t (6) v ti y n c ngng t hon ton (tc nhn l nc lnh). Mt phn cht lng sau khi ngng t c a hi lu tr v thp chng luyn v cng c khng ch bng lu lng k , phn cn li t yu cu s c a vo thit b lm lnh (7) lm lnh n nhit cn thit sau c a vo thng cha sn phm nh (8). Cht lng hi lu i t trn xung di, gp hi c nhit cao i t di ln , mt phn cu t c nhit cao tip tc ngng t thnh lng i xu ng. Do nng cu t kh bay hi trong pha lng ngy cng nhiu, cui cng y thp ta thu c hn hp lng gm hu ht l cu t kh bay hi v mt phn rt t cu t d bay hi,hn hp lng c a ra khi y thp qua thit b phn dng, mt phn c a ra thng cha sn phm y (9), mt phn c a vo thit b un si y thp (10) v mt phn c hi lu tr li y thp . Thit b ny c tc dng un si tun hon v bc hi sn phm y (to dng hi i t di ln trong thp). Nc ngng ca thit b gia nhit c tho qua thit b tho nc ngng ( 11), Thp chng luyn lm vic ch lin tc, hn hp u c a vo lin tc v sn phm c ly ra lin tc.


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CHNG 2 TNH TON THIT B CHNH2.1 TNH TON CN BNG VT LIU CHO TON THIT B 2.1.1.Thng s ban u Gi thit S mol pha hi i t di ln bng nhau trong mi tit din ca thp S mol cht lng khng thay i theo chiu cao on chng v on luyn Hn hp u i vo thp nhit si Cht lng ngng t trong thit b ngng t c thnh phn bng thnh phn ca hi i ra t nh thp Cp nhit y thp bng hi t gin tip b. K hiu cc i lng F: Lng nguyn liu u (kmol/h) P: Lng sn phm nh (kmol/h) W: Lng sn phm y (kmol/h) GF: Lng nguyn liu u (kg/h) GP: Lng sn phm nh (kg/h) GW: Lng sn phm y (kg/h) xF: Nng phn mol cu t d bay hi trong hn hp u xP: Nng phn mol cu t d bay hi trong sn phm nh xW: Nng phn mol cu t d bay hi trong sn phm y aF : nng cu t d bay hi trong hn hp u (phn khi lng) a. aP : nng cu t d bay hi trong sn phm nh (phn khi lng) aw: nng cu t d bay hi trong sn phm y (phn khi lng) Axeton: k hiu l A c MA = 58(kg/kmol) Nc: k hiu l B c MB = 18(kg/kmol) c. Yu cu thit b Thit b chng luyn loi lin tc loi thp m lm vic p sut thng phn tch hn hp Axeton - Nc Nng sut thit b tnh theo hn hp u: GF=4200kg/h aF: 40% khi lng aP: 98% khi lng aW: 3% khi lng11


n Ha cng


2.1.2 Cn bng vt liu Hn hp u vo F (axeton nc) c phn tch thnh snphm nh P (axeton), v sn phm y W (nc). a trn cngc 1 lng lng hi lu, y thp c thit b un si. Lng hi i ra nhthp Do.

a. Phng trnh cn bng vt liu Phng trnh cn bng vt liu cho ton thp GF = GP + Gw (1)(IX.16 STQTTB- II tr.144) Vit cho cu t d bay hi GF . aF= GP . aP + Gw .aW (2)(1)(2) GF ap aW GP aF aW GW aP aF

GPT(1)

GF

aF aP

aW aW

4200

0,40 0,98

0,03 0,03

1635,79( kg / h)

GW= GF - GP = 4200 1635,79= 2564,21 (kg/h)

-

b. i nng phn khi lng sang nng phn mol Nng phn mol: p dng cng thc12


n Ha cng


x

aA MAA

aA MA

aB MB

aA MA

aA MA (1 a A ) M B

[VIII.1 STQTTB-II tr.126]

Thnh phn mol trong hn hp u:aF MA aF 1 aF MA MB 0,40 58 0,40 1 0,40 58 18

xF

0,1714

Thnh phn mol trong sn phm nh:aP MA a p 1 aP MA MB 0,98 58 0,98 1 0,98 58 18

xP

0,9383

Thnh phn mol trong sn phm y:aW MA 1 aW MB 0,03 58 0,03 1 0,03 58 18

xW

aW MA

0,0095

-

Khi lng mol trung bnh:

MF = xFMA +(1-xF)MB = 0,171458 + (1-0,1714)18 = 24,856 (kg/kmol) MP = xPMA +(1-xP)MB = 0,938358 + (1-0,9383)18 = 55,532 (kg/kmol) MW = xWMA +(1-xW)MB = 0,009558 + (1-0,0095)18 = 18,38 (kg/kmol) F

Lu lng tnh theo kmol:GF MF GP MP GW MW 4200 24,856 1635,79 55,532 2564 ,21 18,38 168,973 (kmol/h)

P

29,457 (kmol/h)

W

139,511 (kmol/h)

Bng tng kt thnh phn nh sau:Sv: Phm Th M Hnh Lp LTC-H Ha 5k413

n Ha cng


Thnh phn

Nng phn khi lng 0,40

Nng phn mol

Lu lng khi lng (kg/h) 4200

Lu lng mol (kmol/h)

Hn hp u Sn phm nh Sn phm y

0,1714

168,973

0,98

0,9383

1635,79

29,457

0,03

0,0095

2564,21

139,511

2.2 XC NH S A L THUYT 2.2.1. Phng trnh ng nng lm vic ca thp a. Phng trnh ng nng lm vic ca on luyn Gi V0 l lng hi i trong on luyn Gi L0 l lng lng i trong on luyn Gi P l lng sn phm nh thu c Phng trnh cn bng vt liu V0 = L0 + P Vit cho cu t d bay hi: V0y = L0x + Pxp Trong : y: Nng cu t d bay hi trong pha hi x: Nng cu t d bay hi trong pha lng

y

L0 .x V0

P xp V0

L0 L0y L0

P

x

P L0x

P

xpP P

Chia c t v mu cho P

L0 P P P

L0

P P

xp


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n Ha cng


t R=L0/P

y

R R 1

.x

xp R 1

Phng trnh ng nng lm vic ca on luyn c dng: Y = Ax + B vi A b. R R 1

, B

xp R 1

Phng trnh ng nng lm vic ca on chng Gi V l lng hi i trong on chng Gi Ll lng lng i trong on chng Gi W l lng sn phm y thu c

Phng trnh cn bng vt liu: V = L - W Vit cho cu t d bay hi: Vy = Lx - Wxw (Vi W=F-P v L=L0+F) y' L0 L0 F .x P F P .xW L0 P

Chia c t v mu cho P:y' L0 / P L0 / P F/P .x P/Py' R R

F/P L0 / Pf .x 1

P/P . xW P/ Pf R 1 .xW 1

t F/P=f

Phng trnh c dng: y=Ax + B Vi A'R R f 1

B'

f R

1 xw 1

2.2.2 Xc nh s bc thay i nng a. Thnh phn ca hn hp hai cu t axeton-nc x y t 0 0 100 5 10 20 30 40 50 60 70 80 90 100 60,3 72 80,3 82,7 84,2 85,5 86,9 88,2 90,4 94,3 100 77,9 69,6 64,5 62,6 61,6 60,7 59,8 59 58,2 57,5 56,9

Bng 2.1: Thnh phn cn bng lng(x) hi (y) v nhit si ca hn hp axeton-nc 760mmHg


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n Ha cng


T bng s liu trn ta v ng cn bng trn th x - y v v th t - x,y. th y-xo th ca n ba ng aceyone- n c 100

80

Tha nh pha n pha hi

60

40

20

0 0 20 40 60 80 100

Tha nh pha n pha long

Gi y*F, y*P, y*W l nng phn mol ca pha hi cn bng vi pha lng trong hn hp u, sn phm nh, sn phm y. Gi tF, tP, tW : nhit si ca hn hp u, sn phm nh, sn phm y. Da vo th ta c bng kt qu sau:Sn phm F P W x ( mol) 0,1714 0,9383 0,0095 y* ( mol) 0,7881 0,9633 0,3822 tos (oC) 65,41 57,26 93,79


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n Ha cng


b. Xc nh ch s hi lu Ch s hi lu ti thiu: RminRmin xP y* F* yF xF

0,9383 0,7881

0,7881 0,1714

0,2435

Ch s hi lu thch hp: Rth Rth = Rmin (Trong l h s: 1,1 2,5)

Xc nh Rth theo s bc thay i nng c tin hnh nh sau : Cho nhiu gi tr Rth ln hn Rmin. vi mi gi tr trn, ta xc nh c tung ca ng lm vic vi trc tung l B.

Bc. Xc nh s a l thuyt

xp Rth 1

Cch xc nh s a l thuyt theo phng php s bc thay i nng bng th y - x nh sau: Trn th y-x v ng cho y=x V ng cn bng theo bng 2.1 V ng lm vic ca on chng, on luyn T M k ng thng song song vi trc honh ct ng cn bng u th dng li ti . T im ct k ng thng song song vi trc tung ct ng lm vic u th dng li . Tng t nh vy k song song vi trc honh ct ng cn bng u ri dng li , sau k song song vi trc tung ct ng lm vic u li dng . Lm nh vy cho n khi im cui cng c nng nh hn hoc bng xw. m s tam gic thu c ta tm c s a l thuyt hay s bc thay i nng . Chn =1.1B xp Rth 1 0,9383 0,7400 0,2680 1

ng lm vic ca on luyn nm ngoi ng cn bng.


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n Ha cng


Chn =1,5

B

xp Rth 1

0,9383 0,68727 0,36525 1


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n Ha cng


Chn =1,6

B

xp Rth 1

0,9383 0,6752 0,3896 1

Chn =1,8

B

xp Rth 1

0,9383 0,65237 0,4383 1


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n Ha cng


Chn =1,8

B

xp Rth 1

0,9383 0,65237 0,4383 1


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n Ha cng


Chn =2,0

B

xp Rth 1

0,9383 0,6310 0,487 1


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n Ha cng


Chn =2,2

B

xp Rth 1

0,9383 0,6101 0,5357 1


22

n Ha cng


Chn =2,3

B

xp Rth 1

0,9383 0,60145 0,56005 1


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n Ha cng


Chn =2,4

B

xp Rth 1

0,9383 0,5922 0,5844 1


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n Ha cng


Chn =2,5

B

xp Rth 1

0,9383 0,6088 1

0,58325

Da vo th ta c bng kt qu sau: Rth Bi Nlt Nlt(Rth+1) 1,5 0,3653 0,6873 20 27,305 1,6 0,3896 0,6752 16 22,2336 1,8 0,4383 0,6524 11 15,8213 2,0 0,487 0,6310 10 14,87 2,2 0,5357 0,6101 9 13,8213 2,3 0,560 0,5922 8 12,48 2,4 0,5844 0,6014 8 12,6752 2,5 0,5833 0,5922 8 12,666


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n Ha cng


Theo bng kt qu trn ta v th Nlt(Rth+1):

Nlt(Rth+1)

27,305

12,48

0,3653 0,4383

0,56

0,609

Rth

Theo th ta thy vi Rth = 0,56 th Nlt(Rth+1) l nh nht hay th tch thp nh nht. Vy ta c Rth = 0,56 theo bng trn xc nh s a l thuyt Nlt = 8 a. Ta c phng trnh ng lm vic ca on chng v on luyn: on luyn: y = 0,359.x + 0,6015 on chng: y = 4,036x 0,029 2.3 NG KNH THP CHNG LUYN ng knh thp c xc nh theo cng thc:D 0,0188 g tb (y y

) tb

(m)

[IX.90 STQTTB-II tr.181]

Trong gtb: lng hi trung bnh trong thp (kg/h)(y y

) tb :

tc hi trung bnh i trong thp (kg/m 2..s)


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n Ha cng


2.3.1 Lng hi trung bnh i trong thp V lng hi v lng lng thay i theo chiu cao ca thp v khc nhau trong mi on nn ta phi tnh lng trung bnh cho tng on .

gd

GR

GP xP

GF xF G1 x1=xF

g1, y1

g1', y1' = yw* G1', x1' Gw xw

a.

Lng hi trung bnh i trong on luyn

Lng hi trung bnh i trong on luyn tnh gn ng bng trung bnh cng ca lng hi i ra khi a trn cng ca thp v lng hi i vo a di cng ca on luyn:g tb g g1 (kg/h) 2[IX.91 STQTTB-II tr. 181]

Trong gtb: lng hi trung bnh i trong on luyn (kg/h) g: lng hi i ra khi a trn cng ca thp (kg/h) g1: lng hi i vo a di cng ca on luyn (kg/h) Lng hi ra khi nh thp: g = GP + GR = GP ( Rth+1) = 1635,79 ( 0,56 +1) = 2551,8324 (kg/h) Trong : GP l lng sn phm nh (kg/h) GP=1635,79 (kg/h) GR: l lng cht lng hi lu (kg/h) GR=GP*RthSv: Phm Th M Hnh Lp LTC-H Ha 5k427

n Ha cng


Lng hi i vo on luyn g1: Lng hi g1, hm lng hi y1 v lng lng G1 i vi a th nht ca on luyn c xc nh theo h phng trnh sau: g1 G1 GP g1 y1 G1 x1 GP x p (*)[STQTTB-II tr.182] g1r1 g r Trong cc phng trnh trn ta coi x1=xF (phn khi lng) G1: lng lng i vo a th nht ca on luyn (kg/h) r1: n nhit ho hi i ca hn hp vo a th nht ca on luyn (kJ/kg) r: n nhit ho hi ca hn hp i ra khi nh thp (kJ/kg) Xc nh n nhit ha hi ca hn hp vo a th nht ca on luyn:

r1 = rA y1 + ( 1- y1) rB rA: n nhit ha hi ca axeton tF=65,41oC rB: n nhit ha hi ca nc tF=65,41oC T bng s liu [I.212 STQTTB-I tr.254] Da theo cng thc ni suy:rA r 1 r1 r2 (t F t 2 t1 t1 ) 124 124 113 (65,41 60) 122,512(kcal / kg ) 100 60 512,933(kJ / kg )

Tng t nh trn ta cr B 579 579 539 (65,41 100 60 60) 573,59(kcal / kg ) 2401,507 (kJ / kg )

r1 = rA y1 + ( 1- y1) rB=512,933y1+(1-y1)2401,507=2401,507-1888,574y1 Xc nh n nhit ha hi ca hn hp i ra t nh thp:

r = ra y + ( 1- y) rb ra: n nhit ha hi ca axeton tP=57,26oC rb: n nhit ha hi ca nc tP=57,26oC T bng s liu [I.212 STQTTB-I tr.254] Da theo cng thc ni suy:ra r 1 r1 r2 t 2 t1 (t F t 1 ) 132 132 124 (57,26 60 20 20) 124,548(kcal / kg ) 521,458(kJ / kg )


28

n Ha cng


Tng t nh trn ta crb 584 584 60 579 20 (57,26 2 0) 579,3425 ( kcal / kg ) 2425,591( kJ / kg )

r=521,458y+(1-y)2425,591=2425,591-1904,133y

Mt khc y=yP=aP=0,98 phn khi lng r=2425,591-1904,133*0,98=559,5407 (kJ/kg) Thay cc gi tr r, r1, x1=aF,xP=aP, GP vo cng thc (*)g1 g1 y1 g1r1 g1 y1 G1 G1 GP GP x pg1 g1 y1 G1 1635,79 G1 0,4 1635,79 0,98 2551,8324 559,5407

G1 x1 g r

g1 (2401,507 1888,574 y1 )

1955 ,956 0,885 320,166

Thay y1=0,885 vo r1 ta c r1=730,119 (kJ/kg) Vy lng hi trung bnh trong on luyn :g tb g g1 2551,8324 1955 ,956 = 2 2 2253,894 (kg/h)

b.

Lng hi trung bnh i trong on chng

Lng hi trung bnh i trong on chng c xc nh gn ng bng trung bnh cng ca lng hi i ra khi on chng v lng hi i vo on chng.

g tb 'Trong :

g 'n g '1 2

(kg/h) [IX.96 STQTTB-II tr.192]

gn: lng hi i ra khi a trn cng ca on chng g1: lng hi i vo a th nht ca on luyn V lng hi i ra khi on chng bng lng hi i vo a th nht ca on luyn gn=g1 nn ta c th vit:

g tb '

g1 g '1 2

[IX.97 STQTTB-II tr.192]


29

n Ha cng


Lng hi i vo on chng g1, lng lng G1 v hm lng lng x1 c xc nh theo h cn bng vt liu v cn bng nhit lng sau: G '1 g '1 r '1 Trong : y1=yw tm theo ng cn bng ng vi xw=0,0095(phn mol) ta c yw=0,3822(phn mol). i yw t phn mol sang phn khi lng.yw 0,3822 58 0,3822 58 (1 0,3822 ) 18 0,666 (phn khi lng)

g '1 Gw g '1 yw g 'n r 'n Gw xw g1r1

(**)

G '1 x'1

r1: n nhit ha hi ca hn hp i vo trong a th nht ca on chng

r '1 r A y'1 (1

y'1 )rB

r A yw

(1

yw )rB

rn: n nhit ha hi ca hn hp i vo a trn cng ca on chng

r 'n

r Ay'n (1

y'n )rB

T bng s liu [I.212 STQTTB-I tr.254] Da theo cng thc ni suy ta c: rA: n nhit ha hi ca axeton tF=93,79oC rB: n nhit ha hi ca nc tF=93,79oCrA r 1 r1 r2 (t w t1 ) 124 t 2 t1 r1 r2 (t w t1 ) t 2 t1 579 124 113 (93,79 60) 114,708(kcal / kg ) 100 60 579 539 (93,79 60) 545,21(kcal / kg ) 100 60 480,26(kJ / kg )

rB r 1

2282,685(kJ / kg )

r1=480,260,666+(1-0,666)2282,685=1082,27(kJ/kg) Thay r1, r1, x1,g1, Gw, xw vo h (**)G '1 g '1 2564,21 G '1 x'1 g '1 0,666 2564,21 0,03 g '1 r '1 1955,956 730,119

G '1 x'1 g '1

3883,73 0,246 1319 ,52

Vy lng hi trung bnh trong on chng l :g tb ' g1 g '1 1 955,956 1319,52 1 637,738( kg / h ) 2 230


n Ha cng


2.3.2. Khi lng ring trung bnh Khi lng ring trung bnh ca pha hi:[IX.102 STQTTB-II tr.183] ytbA M A (1 ytbA ) M Bytb

22,4.T

273( kg / m 3 )

Khi lng ring trung bnh ca pha lng

1xtb

atbAxA

1 atbAxB

(kg / m 3 ) [IX.104 STQTTB-II tr.183]

a. Khi lng ring trung bnh ca on luyn Khi lng ring trung bnh ca on luyn i vi pha hiytbAL M AytbL

(1 ytbA L ) M B 273( kg / m 3 ) 22,4.T

Trong MA, MB : khi lng phn mol ca cu t Axeton v nc. T : nhit lm vic trung bnh ca thp ( oK) ytbL: nng phn mol ca cu t Atrong on luyn ly theo gi tr trung bnh

ytbL

y A 2

ycA

y1

y *P 2

[STQTTB-II tr.183]

yA, ycA: nng lm vic ti hai u on luyn ( phn mol) y1 = 0,885 phn khi lng , i sang nng phn mol ta cy1 0,885 / 58 0,885 / 58 (1 0,885) / 18 0,705 (phn mol)

ytbAL

y1

y *P 2

0,705 0,9638 2

0,8344

(phn mol)

Vi ytbL = 0,8344 phn mol. Ni suy t s liu trong bng IX.2a trong [STQTTB-II tr. 145] ta c totb = 62,1oC T = 335,1oK. Vy khi lng ring trung bnh ca on luyn i vi pha hi :y tbAL M AytbL

(1 ytbAL ) M B .273 22,4.T

0,8344 58 (1 0,8344 ) 18 .273 1,8685(kg / m 3 ) 22,4 335,1


31

n Ha cng


Khi lng ring trung bnh ca on luyn i vi pha lng1xtbL

atbLxA

1

atbLxB

( kg / m 3 )

Trong xA, xB:

xtb

: khi lng ring trung bnh i vi pha lng (kg/m3)

khi lng ring ca cu t A v B ca pha lng ly theo totb, (kg/m3)

atbL: phn khi lng trung bnh ca cu t A trong pha lngatbL xtbL aF aP 2 xF 2 xP 0,4 0,98 0,69 (phn khi lng) 2 0,1714 0,9383 2 0,5549 (phn mol)

Vi xtbAL = 0,5549 phn mol. Ni suy theo bng IX.2a trong [STQTTB-II-145] ta c toxtb = 60,21oC Vi toxtb = 60,21oC ni suy theo bng I.2 trong [STQTTB- I tr.9] ta c:xtbA

= 745,72 kg/m3 = 982,88 kg/m

xtbB

Vykhi lng ring trung bnh ca on luyn i vi pha lng:

1xtbLxtbL

atbLxA

1 atbLxB

0,69 745,72

1 0,69 982,88

1,24068 .10

3

=806,01 (kg/m3)

b. Khi lng ring trung bnh ca on chng Khi lng ring trung bnh ca on chng i vi pha hi:ytbAC M AytbC

(1 ytbAC ) M B 273( kg / m 3 ) 22,4.T

Trong MA, MB : khi lng phn mol ca cu t Axeton v nc. T : nhit lm vic trung bnh ca thp ( oK) ytbAC: nng phn mol ca cu t Atrong on chng ly theo gi tr trung bnhSv: Phm Th M Hnh Lp LTC-H Ha 5k432

n Ha cngy A 2 ycA y1 y *w 2

H Cng Nghip H Ni Khoa CN Ha0,705 0,3822 2

ytbC

0,5436 [STQTTB-II tr.183]

yA, ycA: nng lm vic ti hai u on chng ( phn mol) Vi ytbC = 0,5436 phn mol. Ni suy t s liu trong bng IX.2a trong [STQTTB-II tr. 145] ta c totbC = 80,08oC T = 353,08oK. Vy khi lng ring trung bnh ca on chng i vi pha hi :ytbC

0,5436 58 (1 0,5436 ) 18 ytbAC M A (1 ytbAC ) M B .273 .273 1,3719 ( kg / m 3 ) 22,4.T 22,4 353,08

Khi lng ring trung bnh ca on chng i vi pha lng

1xtbC

atbACxA

1 atbACxB

(kg / m 3 )

Trong xA, xB:

xtbC

: khi lng ring trung bnh i vi pha lng (kg/m3)

khi lng ring ca cu t A v B ca pha lng ly theo totb, (kg/m3)

atbC: phn khi lng trung bnh ca cu t A trong pha lng on chngatbC xtbC aF 2 xF 2 xW aw 0,4 0,03 0,215 (phn khi lng) 2 0,1714 0,0095 2 0,09045 (phn mol)

Vi xtbC = 0,09045. Ni suy theo bng IX.2a trong [STQTTB-II tr. 145] ta c toxtb = 71,19oC Vi toxtb = 71,19oC ni suy theo bng I.2 trong [STQTTB- I tr.9] ta c:xtbA

=730,8935 kg/m3 = 976,8455 kg/m

xtbB

Vykhi lng ring trung bnh ca on chng i vi pha lng:

1xtbC

atbACxtbA

1 atbACxtbB

0,215 730,8935

1 0,215 976,8455

1,0978 .10

3

xtbC

=910,9127 kg/m3

2.3.3 Tc ca kh (hi) i trong thpSv: Phm Th M Hnh Lp LTC-H Ha 5k433

n Ha cng


Tc ca kh v hi i trong thp c xc nh theo cng thc sau:(0,8 0,9)s

Vi

s

: l tc sc, c tnh theo cng thc

Y = 1,2 . e-4X[IX.114 STQTTB-II tr. 187] Vi Y2 s

.

d

.

0 ,16 ytb xtb x y

1/ 4

g.V d3 .d:

X

Gx Gy

1/8 yt b xtb

Trong

b mt ring ca m (m2/m3) (m2/s)

Vd: th tch t do ca m (m3/ m3) g : gia tc trng trng Gx,Gy : lng lng v lng hi trung bnh (kg/s)xtb

,

ytb

: khi lng ring trung bnh ca pha lng v pha hi (kg/m 3)

x

: nht ca pha lng theo nhit trung bnhn

= 1,005.10-3 nht ca nc 20oC (N.s/m2), tra bng I.102 trong [STQTTBa. Tc hi i trong on luyn

I tr.94].

Tnh Gx,Gy : Gy = gtb = 2253,894 (kg/h)Gx G1 2 GR G1 GP .Rth 2 320,166 1635,79 0,56 2 618,104 (kg/h)

Tnh nht: - nht ca pha lng totb= 60,21oC Ni suy theo bng I.101 trong [STQTTB-I tr. 91] ta c:A

= 0,2297 . 10-3 N.s/m2,

B

= 0,4678 . 10-3 N.s/m2

Vy nht ca pha lng trong on luyn tnh theo nhit trung bnh l : lglghL hh hL

= xtbL. lgxL

A

+ (1- xtbL) . lg

[STQTTB-I tr. 84] B

= lg

= 0,5549. lg(0,2297.10-3 ) + (1- 0,5549) . lg(0,4678.10-3 )=-3,50135

= 3,15 . 10-4 (N.s/m2)

Thay s liu ta c: Sv: Phm Th M Hnh Lp LTC-H Ha 5k434

n Ha cng1/ 4

H Cng Nghip H Ni Khoa CN Ha1/ 4 1/ 8

X

Gx Gy

1/ 8 ytb xtb

618,104 2253,894

1,8685 806,01

0,3390

Y = 1,2 . e-4 . 0,3390 = 0,3092

Chn m vng loi Rasiga loi ln xn kch thc: 25 x 25 x 30 tra t bng IX.8 [STQTTB-II tr.193] Kch thc m (mm) 25 x 25 x 30 B mt ring, , m2/m3 195 Th tch t do, Vd, m3/m3 0,75 S m trong 1m3 46.103 Khi lng ring xp, d , kg/m3 600

Vi loi m vng ta chn nh trn nn: Y = 0,3092 =2 s

.

d

.

0 ,16 ytb xtb xL n

g.V d3 .

3,15.10 4 . 3 9,81.0,75 3.806,01 1,005.10 .195.1,8685

2 s

0 ,16

s

= 1,8461 (m/s)

Vn tc hi i trong on Luyn l:L

= 0,85. b.

s

= 0,8.1,8461 = 1,47688 (m/s) Tc hi i trong on chngTnh Gx,Gy :320,166 3883,73 2 2101,948 kg h

G1 G1' GxC = 2

GyC = gtb = 1637,738 (kg/h) Tnh nht:

lg

xC

xtbC lg71,19 o C

A

(1

xtbC ) lg

N

I.12 [STQTTB-I tr.84]

A ; B: ln lt l nht ca 2 cu t Axeton v Nc nhit o t xtbC

o T bng I.101[STQTTB-I tr.91] ni suy vi t xtbc

71,19 o C

A = 0,2132.10-3 (N.s/m2) B = 0,40634.10-3 (N.s/m2)Sv: Phm Th M Hnh Lp LTC-H Ha 5k435

n Ha cng


Vy nht ca pha lng trong on chng tnh theo nhit trung bnh l : lglghC hC

= xtbC. lg

A

+ (1- xtbC) . lg

[STQTTB-I tr. 84] B

xC

= 0,09045lg(0,2132.10-3 )+(1-0,09045) . lg(0,40634.10-3 )=-3,41645

= 3,833 . 10-4 (N.s/m2)

Thay s liu ta c:1/ 4

X

Gx Gy

1/ 8 ytb xtb

2101,948 1637 ,738

1/ 4

1,3719 910,9127

1/ 8

0,4724

Y = 1,2 . e-4 . 0,4724 = 0,18136

Chn m vng loi Rasiga loi ln xn kch thc: 25 x 25 x 30 tra t bng: IX.8 [STQTTB-II tr.193] Kch thc m (mm) 25 x 25 x 30 B mt ring, , m2/m3 195 Th tch t do, Vd, m3/m3 0,75 S m trong 1m3 46.103 Khi lng ring xp, d , kg/m3 600

Vi loi m vng ta chn nh trn nn: Y = 0,18136 =2 s

.

g .V .

d 3 d

.

0 ,16 ytb xtb xC n

3,833.10 .195.1,3719 . 3 9,81.0,75 .910,9127 1,005.10

2 s

4 3

0 ,16

s

= 1,72682 (m/s)

Vn tc hi i trong on Chng l:C=

0,8.

s

= 0,8.1,72682 = 1,3815 (m/s)

2.3.4 ng knh thp chng luyn a. ng knh on luyn DL 0,0188 . g tb ytbL . 0,0188 .L

2253,894 1,8685 .1,47688

0,54 m

Quy chun ta ly ng knh l: DL = 0,6m. Th li iu kin lm vic thc tSv: Phm Th M Hnh Lp LTC-H Ha 5k436

n Ha cng


y

Tc hi thc t i trong on chng:1,1843 (m/s).

2253,894.0,0188 2 0,62.1,8685

tt s

T s gia tc thc t vi tc sc:1,1843 1,8461 0,6415

Vy chn ng knh l 0,6m c th chp nhn c. b. ng knh on chng DC 0,0188 . g 'tb ytbC . 0,0188 .C

1637 ,738 1,3719 .1,3815

0,553 m

Quy chun ta ly ng knh l: DC = 0,6m. * Th li iu kin lm vic thc t Tc hi thc t i trong on chng:y

1637 ,738.0,0188 2 0,62.1,3719

1,172 , m/s.

T s gia tc thc t vi tc sc:tt s

1,172 1,72682

0,6787

Vy chn ng knh l 0,6m c th chp nhn c. Quy chun ta ly ng knh thp chng l DL = DC = D = 0,6m. 2.4 CHIU CAO THP CHNG LUYN i vi thp m chiu cao lm vic ca thp hay chiu cao lp m c xc nh theo cng thc: H = hdv . my (m)IX.68[STQTTB-II tr. 175]

Trong hdv : chiu cao ca 1 n v chuyn khi (m) my : s n v chuyn khi xc nh theo nng pha hi 2.4.1 Chiu cao ca mt n v chuyn khi Chiu cao ca mt n v chuyn khi c xc nh theo cng thc:Sv: Phm Th M Hnh Lp LTC-H Ha 5k437

n Ha cngm.G y Gx


hv

h1

.h2

IX.75 [STQTTB-II tr.177]

Trong : - h1: l chiu cao ca 1 n v chuyn khi i vi pha hi (m) - h2: l chiu cao ca 1 n v chuyn khi i vi pha lng (m) - m: l h s phn b trung bnh iu kin cn bng pha - Gx, Gy: l lng lng v lng hi trung bnh i trong thp, kg/h Vi h12 3

V a. .

. Re

0, 25 y

. Pr

2 3 y

m IX.76 [STQTTB-II tr.177]

h2

2 56

x x

25 0,5 . Re 0, . Prx m IX.77 [STQTTB-II tr.177] x

a: h s ph thuc vo dngm, vim vng th a = 0,123x:

nht ca pha lng, Ns/m2

Vd: th tch t do cam, m3/m3x:

khi lng ring ca lng, kg/m3

: h s thm t ca m, n ph thuc vo t s gia mt ti thc t ln tit din ngang ca thp v mt ti thch hp, xc nh theo th IX.16[STQTTB-II tr.178]

a. Xc nh chun s Re on chng Chun s Re trong pha hi ca on chngRe yC 0,4.yC yC

.d

sC

[STQTTB-II tr.178]

.

Ta c

hh

=

yC

c tnh theo:

hh hh

m1 .A

A

m2 .B

B

[STQTTB-I tr.85]

M hh

ytbC .M

A

1

ytbC M B

0,5436 .58

1 0,5436 .18

39,744 vC

Trong m1,m2 : nng ca axeton v nc tnh theo phn th tchSv: Phm Th M Hnh Lp LTC-H Ha 5k438

n Ha cng


Trong cng iu kin nhit v p sut t l mol bng t l th tch nn ta c : m1 = ytbAC = 0,5436 phn mol Ti nhit totb= 80,08oC tra theo hnh I.35 ta c:A

= 0,19988 . 10-3 N.s/m2 = 0,3567 . 10-3 N.s/m2

B

Vy M hhyC

yC .yC

MAA

1 yC .

MNN

39,744 58 0,5436 . 0,19988 .100,4.yC yC

3

18 1 0,5436 . 0,3567 .1022,103

2,198.103

4

N .s

m2

Re yC

.

sC

.

0,4.1,3719 .1,72682 4 2,198.10 .195

Chun s Reynolt ca pha lng on Chng Ta c: Re x0,04.Gx Ft . d . x

Trong :t

Gx = 2101,948 (kg/h)D2 C 2 (m ) 4

F =

= 195 2 /m3) (mdx

= 3,833 .10-4N.s/m2 Vy chun s Re ca pha lng

Re xC

0,04.Gx Ft .xC

0,04.2101,948 4 0,6 3,14. .3,833.10 .195 4 2

1,106

.

on LuynSv: Phm Th M Hnh Lp LTC-H Ha 5k439

n Ha cng


Chun s Reynolt pha hi ca on Luyn

0,4. Re yLTrong :yL

yL

.d

s

.

M hhyL

yL .

MAA

1 yL .

MNN

M hh

ytbL .M A

1 ytbL M N

0,8344 .58

1 0,8344 .18 51,376 vC62,1o C

o T bng I.101 [STQTTB-I tr.91] nhit ttbL

A= 0,22685.10-3 N.s/m2 B= 0,45724.10-3 N.s/m251,376yL

0,8344 .

58 0,22685 .103

1 0,8433 .

18 0,45724 .103

2,34.10

4

N .s

m2

Re yL

0,4.1,8685 .1,8461 2,34.10 4.195

30,2383

Chun s Reynolt ca pha lng on Luyn Ta c: Re x0,04.Gx Ft . d . x

Trong :

Gx = 618,104 (kg/h) (m2) Ft =4

D2 L

d

= 195 (m2 /m3)

x

= 3,15 .10-4N.s/m2

Vy chun s Re ca pha lngRe 0,04.G xxL

0,04.618,104 4 0,6 3,14. .3,15.10 .195 4 2

0,3956

Ft .

xL

.


40

n Ha cng


b. Xc nh h s khuch tn


41

n Ha cng


on Chng H s khuych tn ca pha hi on ChngD yC 0,0043 .10 .T PC . v1 3 A 4 3 2 C 2

.

v

1 3 B

1 MA

1 m2/s. MB

VIII.5 [STQTTB-II-127]

Trong : DyC : l h s khuch tn ca pha hi, m2/s. PC : l p sut tuyt i ca h 2 cu t Axeton Nc = 1atA

;

B

: ln lt l th tch mol ca hi Axeton Nc , cm3/mol.

TC : l nhit tuyt i ca on chng MA , MB : l khi lng mol phn t ca 2 cu t Axeton - Nc ( vC) Tra bng VIII.2 [STQTTB-II -127] ta c th tch nguyn t ca C = 14,8: H = 3,7; O = 7,4 + +A

= 3.14,8 + 6.3,7 +7,4 = 74, cm3/mol. = 2.3,7 + 7,4 = 14,8, cm3/mol.

B

M T = 80,08 + 273 = 353,080K Thay vo ta c :3 3

DyC

0,0043 .10 .T PC . v1 3 A

4

v

1 3 N

2 C 2

.

1 MA

1 MN

0,0043 .10 .(353,08) 2 1. 741 3

4

14,8

1 3

2

.

1 1 1,7375 .10 5 m 2 / s 58 18

H s khuch tn ca hn hp lng 20o C10 6. DxC 20 A.B. 1 MAN 20

1 MB1 3 A 1 3 B 2

[STQTTB-II-133]

.

Trong :


42

n Ha cng


- A, B : l h s ph thuc vo bn cht dung mi v cht tan , l h s lin hp k n nh hng ca Axeton v nc Ta c A = 1,15; B = 4,7 - DxC20 : l h s khuch tn ca pha lng 20o C, m2/s. - MA ; MB: l khi lng phn t ca Axeton - Nc A

;

B

: l th tch mol ca Axeton - Nc, cm3/mol.

N 20

: nht ca dung mi nc 200C

T bng I.102 [STQTTB-I-94]N 20

=1,005cP10 6. 1 MAN 20 . 1 3 A

D20 A.B.

1 MB1 3 B 2

10 6.

1 58

1 181 1 2

,1 276 .10

9

m2 / s

1,15.4,7. 1,0 05. 74 3

14,8 3

H s khuch tn ca hn hp lng on Chng DxC D20 1 b ttbC 20 VIII.15 [STQTTB-II-134]

b l h s hiu chnh :

b

0,2.3

N 20 N 20


Ni suy t bng I.2 [STQTTB-I-9] ta c:N 20

998 kg / m 3 0,2. 1,03

b DxC

998

0,02006 20 1,1276 .10 9 1 0,02006 71,19 20 2,855.109

D20 1 b ttbC

m2 / s .

on Luyn H s khuych tn ca pha hi trong on Luyn3

D yL

0,0043 .10 .TL21 3 PL . v A 1 3 vN 2

4

.

1 MA

1 MN

, m2/s VIII.5 [STQTTB-II-127]


43

n Ha cng


Trong : DyL : l h s khuch tn ca pha hi, m2/s. PL: l p sut tuyt i ca h 2 cu t Axeton Nc = 1atA

;

N

: ln lt l th tch mol ca hi Axeton Nc , cm3/mol.

TL: l nhit tuyt i ca on luyn MA , MN : l khi lng mol phn t ca 2 cu t Axeton - Nc ( vC) Ta c: TL= 62,1 + 273 = 335,10K Thay vo ta c :3 3

DyL

0,0043 .10 .T PL . v1 3 A

4

v

1 3 N

2 L 2

.

1 MA

1 MN

0,0043 .10 .(335,1) 2 1. 741 3

4

14,8

1 3

2

.

1 1 1,6067 .10 5 m 2 / s 58 18

H s khuych tn ca pha lng on Luyn DxL D20 1 b t L 20 b l h s hiu chnh b 0,2.3 N 20 N 20



Ni suy t bng I.2 [I-9] ta c:N 20

998 kg / m 3 0,2. 1,03

b DxL

998

0,02006 20 1,1276 .109

D20 1 b ttbL

1 0,02006 60,21

20

2,0371 .10

9

m2 / s .

c. Xc nh chun s Prand on Chng Chun s Prand trong pha hi on ChngPryCyC yC

.D yC

[STQTTB- II- 178]


44

n Ha cng


Thay s ta c : PryCyC yC

.DyC

2,198.10 4 1,3719 .1,7387 .10

5

9,215

Chun s Prand trong pha lng on ChngPrxCxC xC

.DxC

3,833.10 4 910,9127 .2,855.10

9

147,3859

on Luyn Chun s Prand trong pha hi on LuynPryLyL yL .DyL

2,34.10 4 1,8685 .1,6076 .10

5

7,79

Chun s Prand trong pha lng on LuynPrxLxL xL .D xL

2,6083 .10 4 820,428.2,0455 .10

9

155,424

d. Tnh h s thm t on Chng Mt ti thch hp Uth = .B (m3/m2.h) B=0,065, (m3/m.h). H s ny c cho trong bng IX.6 [STQTTB-II-177] : b mt ring ca m, m2/m3. Vi loi m vng Rasiga loi: 25 x 25 x 3,0 th: - Vd = 0,75, m3/m3 - = 195, m2/m3 - a = 0,123 Uth = 195.0,065 = 12,675 (m3/m2.h) Mt ti thc tU ttC VxC (m3/m2.h) Ft

[STQTTB-II- 177]


45

n Ha cng


Trong : VxC : lu lng th tch ca pha lng trong on chng, m3/s. Ft : tit din ngang ca thp (on chng) M: Ft =VxC U ttC GxCxC

.D 2 4

3,14.0,6 2 4

0,2826 (m2)

2101,948 910,9127 2,3075 0,2826

2,3075 m3 h 8,1653 m 3 / m 2 .h

VxC Ft

U ttC U th

8,1653 12,675

0,644

T hnh IX.16 [II-178 ] ni suy c: C = 0,68 Chiu cao ca mt n v chuyn khi i vi pha hi on chng:h1C Vd a. C .25 2/3 . Re0, yC . PryC d

0,75 .22,103 0, 25.9,125 2 3 0,123.0,68.195

0,438 m

Chiu cao ca mt n v chuyn khi i vi pha lng on Chng:h2 C 256 .xC xC 2 3 25 0,5 . Re 0, . PrxC xC 2 3

3,833 .10 4 256 . 910,9127

.1,106 0 , 25.147 ,3859 0, 5

0, 18 m

on Luyn Mt ti thch hp Uth = .B (m3/m2.h) B = 0,065, m3/m.h. H s ny c cho trong bng IX.6 [STQTTB-II-177] : b mt ring ca m, m2/m3 Vi loi m vng Rasiga loi: 25 x 25 x 3,0 th: - Vd = 0,75, m3/m3Sv: Phm Th M Hnh Lp LTC-H Ha 5k446

n Ha cng


- = 195, m2/m3 - a = 0,123 Uth = 195.0,065 = 12,675 (m3/m2.h) Mt ti thc t

U ttL

VxL (m3/m2.h) Ft

[STQTTB- II- 177]

Trong : VxC : lu lng th tch ca pha lng trong on chng, m3/s. Ft : tit din ngang ca thp (on chng) M: Ft = VxLU ttLU ttL U th .D 2 4 3,14.0,6 2 4 0,2826 m2

G xLxL

618,104 806,010,7668 0,2826

0,7668 m 3 h2,71 m 3 / m 2 .h

VxL Ft

2,71 12,675

0,214

T hnh IX.16 [II-178 ] ni suy c: L = 0,23 Chiu cao ca mt n v chuyn khi i vi pha hi on Luyn: h1L V a. L . . Re 0, 25 yL

. Pr

2 3 yL

0,75 .30,2383 0, 25.7,79 3 0,123.0,23.195

2

1,253( m)

Chiu cao ca mt n v chuyn khi i vi pha lng on Luyn: h2 L 256.xL xL 2 3 25 0,5 . Re0, xL PrxL 2 3

3,15.10 4 256. 806,01

.0,3956 0, 25.191,8482 0,5

0,15 m


47

n Ha cng


2.4.2 S n v chuyn khi a. on Chng S n v chuyn khi c xc nh theo cng thc:yF

myyW

dy y*

IX.74 [STQTTB-II-176]

y

Vi mi gi tr ca y trong khong (0,009342 0,66277 ) tm c y*.T xy dng th

1 y* y

f y .

Ta chia on [0,009342; 0,66277] ra thnh 4 on bng nhau, c di:hC yF 2n yw 0,6641 0,0095 4 0,16365

Kt qu c tng hp bng sau:x y y* y* - y1 y* y

0,0095 0,0 5 0,0906 0,1312 0,1714

0,0095 0,17315 0,3368 0,5005 0,66411 y*

0,3822 0,603 0,7028 0,7554 0,7881

0,3727 0,4298 0,366 0,2545 0,124

2,683 2,3266 2,732 3,9293 8,0645

T bng s liu trn ta v th

y

y , t th ta tnh din tch gii hn bi

ng cong, trc honh v hai trc tung yw v yF chnh l s n v chuyn khi cn tm ( y w v yF l nng u v cui ca hi).


48

n Ha cng


1/y*-y

yp dng cng thc SIMSON :F 1*

y y 0,16365 2,683 3

m yC

h F0 3 8,0645

F4

4 F1

F3

2 F2 2 2,732 2,249

4 2,3266

3,9293

b. on Luyn S n v chuyn khi c xc nh theo cng thc:yc

myyd

dy ycb yIX.74 [STQTTB-II-176]

Vi mi gi tr ca y trong khong (0,6641 0,9383) tm c y* .T xy dng th

1 y* y

f y .

Ta chia on [0,6641; 0,9383] ra thnh 10 on bng nhau, c di: hL =0,9383 0,6641 10 0,02742


49

n Ha cng


Kt qu c tng hp bng sau:x y y* y* - y1 y* y

0,1714 0,2507 0,3271 0,4035 0,4799 0,5562 0,6326 0,7090 0,7854 0,8618 0,9383

0,6641 0,69152 0,71894 0,74636 0,77378 0,8012 0,82862 0,85604 0,88346 0,91088 0,9383

0,7881 0,81842 0,8352 0,8440 0,8534 0,8639 0,8752 0,9023 0,9288 0,9526 0,98231 y*

0,124 0.12648 0,11626 0,09764 0,07962 0,0627 0,04658 0,04626 0,04534 0,04172 0,044

8,0645 7,8 8 8,601 10,2417 12,5596 15,9489 21,468 21,6169 22,0555 23,9693 22,7272

T bng s liu trn ta v th

y

y , t th ta tnh din tch gii

hn bi ng cong, trc honh v hai trc tung y F v yP chnh l s n v chuyn khi cn tm ( y F v yP l nng u v cui ca hi). p dng cng thc SIMSON :F 1 y*

y

m yL

h F1 F10 4 F1 F3 ... F9 3

2( F2 F4 F6 F8 ) 3,23

0,02742 8,0645 22,7272 4(7,88 10,2417 15,9489 21,6169 23,9693) 3 2(8,601 12,5596 21,468 22,0555)


50

n Ha cng


2.4.3 Tnh m a. Xc nh m C Chn cc gi tr x bt k, ti mi gi tr x ta tm gc nghing ca ng cn bng, t cc gi tr tm c tnh m theo cng thc:m tg ycb y [STQTTB-II-169] x xcb

Chia ng cn bng thnh 6 phn t xW xF X Xcb Y Ycb m7

0,7 0,0104 2,5589 6,2801 5,396miC 5,396

0,9 0,0551 3,3673 7,0427 4,354,35

1,1 0,1346 4,1758 7,3346 3,2723,272 6

1,3 0,2582 4,9843 7,556 2,4682,468

1,5 0,4360 5,7927 7,7317 1,8221,822

1,7 0,6880 6,6012 7,8726 1,2561,256

mC

i 1

6

3,09

b. Xc nh m L Chn cc gi tr x bt k, ti mi gi tr x ta tm gc nghing ca ng cn bng, t cc gi tr tm c tnh m theo cng thc:m tg ycb y [STQTTB-II-169] x xcbxP

Chia ng cn bng thnh 7 phn t xF X Xcb Y Ycb m 3 0,9182 7,087 8,27 0,568 4 1,186 7,4476 8,42 0,3468 5 1,562 7,807 8,55 0,2161 6

7 4,8211 8,5262 8,82 0,1348

8 7,2708 8,8685 9,04 0,2151

2,4290 8,1667 8,69 0,141


n Ha cng7


miL mLi 1

0,568

0,3468

4

0,2161 0,141 6

0,1348

0,21

0,269

2.4.4 Xc nh chiu cao thpa. on Chng Chiu cao ca mt n v chuyn khi:h vC h1C mC .G yC G xC .h2 C 0,438 3,09.1637 ,738 .0,18 2101,948 0,87 m

Vy chiu cao lp m on Chng l: HC' m yC .h vC 2,249.0,87 1,9566 ( m)

b. on Luyn Chiu cao ca mt n v chuyn khi:h vL h1L mL .G yL G xL .h2 L 1,253 0,269.2253,894 .0,15 1,40 m 618,104

Vy chiu cao lp m on Luyn l:H L' m yL .h vL 3,23.1,40 4,522 m

2.4.5 Chiu cao ton thp Chn: - Khong cch gia cc ngn m l 100mm = 0,1m on Chng c HC = 1,9566m, ta chia lp m on Chng ra thnh cc ngn m nh c chiu cao l: 0,5m. Vy on Chng ta s chia thnh 3 ngn m, vy s khong cch gia cc ngn m l: 3 1 = 2 (khong cch). Do chiu cao ton b lp m on Chng l: HC = HC + 3.0,1 = 1,9566 +0,3 = 2,2566(m) on Luyn c HL = 4,522m, ta chia lp m on Luyn thnh cc ngn m nh c chiu cao l: 0,5m, Vy on Luyn ta s chia thnh 9 ngn m, vy s khong cch gia cc ngn m l: 9 1 = 8 (khong cch). Do chiu cao ton b lp m on Luyn l: HL = HL +8.0,1 = 4,522 + 0,8 = 5,322m


52

n Ha cng


Chiu cao ca lp m: H = HC + HL = 2,2556+5,322 = 7,5776 (m) Vi ng knh thp D = 0,6 (m) - Khong khng gian gia hai lp m on chng v luyn l: 0,5 (m) - Khong cch t m n np Zn = 0,6 ( m ) - Khong cch t m n y Z = 1,5 ( m ) Chiu cao ton thp: HT = 7,5776 + 0,6 + 0,5 + 1,5 = 10,1775(m) 10,2m

2.5 TR LC CA THP MTr lc i vi thp m c th c xc nh theo cng thc:m

PU

G Pk . 1 A x Gy

n

c

.

y x

.

x y

(N/m2)


Trong :PU : Tn tht p sut khi m t ti im o pha c tc ca kh bng tc

ca kh khi i qua m kh, N/m2. Gx, Gy: Lu lng ca lng v kh, kg/hx

, ,

y

: :

Khi lng ring ca lng v kh, kg/m3 nht ca lng v kh, N.s/m2

x

y

2 Pk : Tn tht p sut ca m kh, N/m

Pk'

'

H . d td

y

. 2

2 t

'

.H . . 4.V3

y

. 2

2 y

16 2 Re 0, y

khi Rey> 40

A; m; n ; c : l hng s Tra t bng IX.7 [II-189] ta c : A= 5,15 ; m = 0,342; n = 0,19 ; c = 0,038 Khi Rey < 40 th'

140 Re y


53

n Ha cng0 , 43


Re 'y Ar d td

Gx 0,045 . Ar 0,57 . Gy3 d td . y x 2 y y

.g

4.Vtd

2.5.1 Tr lc on Chng 4.Vtd 4.0,75 d td 195 ArC3 d td . yC xC 2 yC 0 , 43 yC

0,01538 (m)

.g

0,01538 3.1,3719 910,9127 1,3719 .9,81 (2,198.10 4 ) 20,045.9217800.57

921780 ,0

Re

' yC

0,045. Ar

0,57 C

.

G yC G xC

1637 ,738 . 2101,948

0 , 43

104,69

40

Re'yC .yC

yC yC

d td . PkC

104,69.2,198.10 4 0,01538 .1,3719yC

1,091(m / s ) . 22 yC

Vy :

'

HC . d td

.

2 t

'

2

.H C . 4.V 3

.

yC

Vi: do Rey> 40P kC

'

16 2 Re0, y

16.2,2566 .195 1,3719 .1,091 2 . 101,69 0, 2.4.0,753 2m

1351,611( N / m 2 )

PUC

G PkC . 1 A xC GyC

n

c

.

yC xC 0,342

.

xC yC 0,19

1637 ,738 1351,661. 1 5,15 2101,948

1,3719 . 924,413

3,8333 .10 4 . 2,198.10 4

0,038

3245,597


54

n Ha cng


2.52. Tr lc on Luyn d td 4.Vtd3 d td .

4.0,75 195yL xL 2 yL yL

0,01538 ( m).g 0,01538 3.1,8685 806,01 1,8685 .9,81 (2,34.100 , 434 2

ArL

)

979336 ,36

Re y

0,045 Ar

0,57

.

Gy Gx

IX.117 [STQTTB-II-188] 2253,894 . 618,1040 , 43

Re

' yL

0 ,045.979336 ,36

0,57

203,51

Re 'yL .yL

yL yL

d td .Vy :

203,51.2,34.10 4 0,01538 .1,8685'

1,657 ( m / s )' 2 yL

PkL

HL . d td

yL

.

2 t

2

.H L . 4.V 3

.

yL

.

2

Vi:

'

16 0, 2 do Re y> 40 Re y16.5,322.195 1,8685 .1,657 2 . 2 203,510, 2.4.0,75 3m n c

PkL

8717 ,193( N / m 2 )

PUL

G PkL . 1 A xL G yL

.

yL xL 0 ,342

.

xL yL 0 ,19 4 4 0 ,038

618,104 8717 ,193. 1 5,15 2253,894

1,8685 . 806,01

3,15.10 . 2,34.10

17928 ,23( N / m 2 )

Vy tr lc ca ton thp :P PuC PuL 3245,597 17928,23 21173,83


55

n Ha cng


2.6 CN BNG NHIT LNG Qn Qy Q Q2

R

xq

QF QD 1

Q

QD2

n 4

Qxq1 Qf Qng1 Q Qng 2W

QP

2.6.1 Cn bng nhit lng ca thit b un si hn hp uPhng trnh cn bng nhit lng ca thit b un nng hn hp u: QD1 + Qf = QF + Qng1 + Qxq1 (J/h) IX.149[STQTTB-II-196] Trong : QD1 : Nhit lng do hi t mang vo, J/h. Qf : Nhit lng do hn hp u mang vo, J/h. QF : Nhit lng do hn hp u mang ra, J/h.

Q ng1 : Nhit lng do nc ngng mang ra, J/h. Q xq1 : Nhit lng mt mt ra mi trng xung quanh, J/h.Chn hi t l hi nc bo ho p sut 2 at, c to si = 119,62oC a. Nhit lng do hi t mang vo

QD1

D1 .

1

D1 (r1

1

.C1 )( J / h) IX.150[STQTTB-II-196]

Trong : - D1 : lng hi t, kg/h. - r1 : n nhit ha hi, J/h.Sv: Phm Th M Hnh Lp LTC-H Ha 5k456

n Ha cng


-

1:

hm nhit ca hi t, J/kg.( nhit lng ring ca hi t (J.kg)). nhit nc ngng, o C.

1:

- C1: nhit dung ring ca nc ngng, J/kg . b. Nhit lng do hn hp u mang vo Qf = F.Cf.tf (J/h)IX.151[STQTTB-II-196] Trong : - F: lng hn hp u, kg/h = 4200 kg/h - tf: nhit ca hn hp u, o C. Hn hp vo nhit thng: tf = 250C - Cf : nhit dung ring ca hn hp u, J/kg . Ly tf = 25oC v ni suy t bng I.153 [I-171] ta c : CA = 2195 (J/kg ) CN = 4178,75 (J/kg )

Cf

C A aF

(1 aF )C N `

2195 .0,4 (1 0,4).4178,75

3385,25 (J/kg ).

Vy:Qf = F.Cf.tf = 4200.3385,25.25 = 355451250,00 (J/h) c. Nhit lng do hn hp u mang ra QF = F.CF.tF (J/h)IX.152[STQTTB-II-196] F: lng hn hp u, kg/h = 4200, kg/h. tF : nhit si ca hn hp, o C. CF: nhit dung ring ca hn hp i ra khi thit b un si, J/kg .

CF

CAaF

(1 aF )CN `

CA ; CN : ln lt l nhit dung ring ca Axeton, Nc nhit toF = 65,41oC Ni suy t bng I.153 [STQTTB-I-171] ta c : CA = 2322,6 (J/kg ) CN = 4190 (J/kg )

CF CAaF (1 aF )CN ` 2322,6.0,4 (1 0,4).4190 3443,04 (J/kg )Vy: QF = F.CF.tF = 4200.3443,04.65,41 = 945878834,88 ( J/h )Sv: Phm Th M Hnh Lp LTC-H Ha 5k457

n Ha cng


d. Nhit lng do nc ngng mang ra Qng1 = Gng1.C1. Trong : Gng1: Lng nc ngng, bng lng hi t, kg/h Do Gng1 = D1 (kg/h) e. Nhit lng m t mt ra mi trng xung quanh Lng nhit mt ra mi trng ly bng 5% nhit tiu tn Qxq1 = 0,05D1.C1r1 (J/h)IX.154[STQTTB-II-197] f. Lng hi t cn thit un nng dung dch u n nhit si0,95.r 0,95 r 1 1 o o Chn p = 2 at tra bng I.251 [STQTTB-I-314] ta c ts = 119,6 C11

= D1 .C1 . 1 ( J / h) IX.153[STQTTB-II-197]

D1

QF

Qng1

Qxq1

Qf

QF

Qf

F .(CF .t F

Cf tf )

( kg / h)

Vi ts=119,6oCtra bng I.212[STQTTB-I-254] r1=526,247(kcal/kg) =2203290,94 (J/kg).D1 F CF .t F C f .t f 0,95r1 4200 3443,04.65,41 3385,25.25 0,95.2203290 ,94

ta

c

282,08( kg / h)

2.6.2 Cn bng nhit lng ca thp chng luyn Phng trnh cn bng nhit lng ca thp chng luyn: Tng lng nhit mang vo thp bng tng lng nhit mang ra: QF + QD2 + QR = Qy + QW + Qxq + QngtIX.156 [STQTTB-II-197] Trong : QF : nhit lng do hn hp u mang vo thp, J/h. QD2 : Nhit lng do hi t mang vo thp, J/h.

QD 2

D2 r2

C2 .

2

D2 . 2 (J/h)IX.157 [STQTTB-II-197]

- QR: Nhit lng do lng lng hi lu sn phm nh mang vo thp : QR = GR.CR.tR (J/h)IX.158 [STQTTB-II-197] Qy:Nhit do hi mang ra nh thp :


58

n Ha cng


Qy

P 1 Rth .A

N

.a P 1 a P


-

Qw :Nhit lng do sn phm y mang ra :

QW

W .CW .tW (J/h)IX.160 [STQTTB-II-197]Qng2:Nhit do nc ngng mang ra :2

Qng 2

Dngt .C2 .

D2 .C2 . 2 ( J / h) IX.161 [STQTTB-II-198]

Qxq2:Nhit lng mt mt ra mi trng xung quanh : Ly bng 5% nhit tiu tn y thpQ xq 2 0,05 D2 r2 ( J / h) IX.162

[STQTTB-II-198]

Chn hi t l hi nc bo ho p sut 2 at, c t0 si = 119,60C Vy lng hi t cn thit un si sn phm y :

D2

Qy

QW

Qngt2

Q xq 2

QF

QR

(kg/h)IX.163 [STQTTB-II-198]

a. Nhit lng do lng lng hi lu mang vo thp QR = GR.CR.tR = P.Rth.CR.tR Tnh CR: CR

C A .aP

1 aP .CN

T bng I.153 [STQTTB-I-171] nhit to P= 57,26oC CA = 2296,1(J/kg ), CN = 4187,95(J/kg )

CR CA .aP 1 aP .CN 2296,1.0,98 1 0,98 .4187,95 2333,94 (J/ kg )Tnh GR:GR = P . Rth = 1635,79.0,56= 916,04(J/h ) Vy: QR = GR.CR.tR = 916,04.2333,94.57,26 = 122420872,09 ( J/h ) b. Nhit lng do hi mang ra nh thp

Qyd A N

P ( Rth 1)

d N

a P A (1 aP ) rA t P .C A rN tP .C N


59

n Ha cng


Tra bng I.212[STQTTB-I-254] ni suy nhit toP = 57,26oC c:rA rN 124,548(kcal / kg ) 579,34(kcal / kg ) 521457 ,57( J / kg ) 2425580 ,72( J / kg ) rA tP .C A 521457 ,57 57,26.2296 ,1 652932 ,25( J / kg ) A rN t N .C N 2425580 ,72 57,26.4187 ,95 266538 ,74( J / kg ) a P A (1 aP ) N 0,98.652932 ,25 (1 0,98).2665382 ,73 Qy P( Rth 1)

N

693181,26( J / kg )

1635,79.(0,56 1).693181,26

1768907916 ,67( J / h)

c. Nhit lng do sn phm y mang ra QW = CW.W.tW ( J/h )0

T xw=0,0095 ni suy theo bng IX.2a [STQTTB-II-145] ta c t w

93,79 0 C

CW

C A .aw

(1 aw )CN

Ni suy t bng I.153[STQTTB-I-171] c CA = 2414,82 (J/ kg ) CN = 4217,58 ( J/kg )CW C A .aw (1 aw )CN 2414,82.0,03 (1 0,03).4217,58 4163,50

QW

W .CW .tW

2464,71.4163,5.93,79

1001504898 ( J / h)

d. Nhit lng do nc ngng mang ra

Qngt

D2 .C2 .

2

T bng I.149 [I-168] ta c Qngt D2 .C2 .2

2

119,62 o C

C2

2156,11 ( J/kg )

2156,11.119,62 D2

257913 ,878 D2 ( J / h)

Nhit tn tht ra mi trng : Qxq = 0,05.D2r2 = 0,05.2203290,94D2 Lng hi t cn thit un si lng sn phm y :D2 Qy QW QF QR 0,95 r2 1768907916 ,67 1001504898 ,75 122420872 ,10 945878834 ,88 0,95.2203290 ,94

813,20( kg / h)


60

n Ha cng


2.6.3 Cn bng nhit lng cho thit b ngng tPhng trnh cn bng nhit lng cho thit b ngng t (ngng t hon ton): P(Rth +1)r = GnlCn(t2 t1) [STQTTB-II-198] Trong : r: n nhit ngng t, J/kg Nhit ca hi nh thp l: t0d = 57,260C Tra bng I.212[STQTTB-I-254] ni suy nhit toP = 57,26oC c :

rA rN

1 24,548(kcal / kg ) 521457 ,57( J / kg ) 579,34(kcal / kg )rn g rA .a P

2425580 ,72( J / kg )

(1 a P )rN 1 0,98 .2425580 ,728 559540 ,03( J / kg )

521457 ,57.0,98

Cn: Nhit dung ring ca nc nhit trung bnh (J/kg. ) Gnl: Lng nc lnh tiu tn cn thit, kg/h. t1, t2: Nhit vo v ra ca nc lm lnh, 0C Nhit vo ca nc lnh ly l nhit thng: t1 = 250C Nhit ra ca nc lnh chn l: t2 = 450Cttb 25 45 2 3 5o C

Tra t bng I.153 [I-171] ta c Cn = 4176,25(J/kg ) Vy lng nc lnh cn thit ngng t hon ton sn phm nh :Gnl P.(1 Rth ).r Cn (t2 t1 ) 1612 ,903.(1 0,595).599321,9981 4176 ,25.(45 25) 18459 ,19(kg / h)

2.6.4 Cn bng nhit lng ti thit b lm lnhCoi lm lnh sau khi ngng t hon ton th ta c phng trnh cn bng nhit lng ca thit b lm lnh:' P.C P (t1' t 2 )

Gn 4 .Cn .(t 2

t1)



61

n Ha cng


Trong : Gn4: Lng nc lnh tiu tn, kg/h. T1, t2: Nhit u v cui ca sn phm nh ngng t, 0C Chn t1 = 15oC ,t2 = 25o C Tnh t1 Hiu s nhit trung bnh:ttb' tP t1 7,26

t 2 t1 T t1 ln T t2ttb 5

45 25 57,26 25 ln 57,26 4520,62 o C

20,62 o C

36,64 o C

Nhit cui ca sn phm nh ngng t ly l: t 2 =250C Vy CP ti t' tb

t1' 2

' t2

36,64 2

25

30,82 o C

Ni suy theo bng I.153 [STQTTB-I-171] ti 30,82oC ta c CA = 2212,46 (J/kg ) CN = 4177,30 (J/kg )CP aP .C A (1 aP ).C N 0,98.2212,46 (1 0,98).4177,30 2251,7568 (J/kg

)

Lng nc lnh tiu tn : Gn 4' P.C P .(t1' t 2 ) C n (t 2 t1 )

1635,79.2251,7568 (36,64 4176 ,25.(45 25)

2 5)

513,32(kg / h)


62

n Ha cng


CHNG 3 TNH TON C KH V LA CHN3.1 TNH TON THN THP3.1.1 Chn vt liu lm thn thp Thp chng luyn c thn hnh tr t thngng lm vic khong nhit t = 25 1000C v p sut thng nn ta chn vt liu lm thn hnh tr thp bng thp cacbon c k hiu CT3. Thp ny rt bn nhit.Thit b thuc nhm 2 loi II H s iu chnh [STQTTB-II-356] l: = 1,0 c trng c hc ca mc thp ny tra t bng XII.4 [STQTTB-II309]v[STQTTB-II-313] Gii Vt liu hn bn kok

gii hn bn chyc

H s0

Khi lng ring (kg/m3) nhit

gin0

H s dn

khi ko 20 -100 C at (1/ C) 11.106 o

(N/m2)

(N/m2)

W/m.

CT3

380.1 06

240.1 06

7,85. 103

50,0

a. Cch ch to: T Dt = 600 (mm) Hn tay bng h quang in vi kiu hn gip mi 1 bn c tm lt khp chu vi. Theo bng XIII.8 [STQTTB-II-362] ta c h s bn mi hn h = 0,9 b. Tnh ton sc bn vt liu : - Cng thc tnh ng sut cho php : do tT< 470o t bng XIII.4-337 dng cng thc XIII.1 XIII.2t k k

nkt C

.

[STQTTB-II-355].

k

nC


63

n Ha cng


Trong : - k : l ng sut ko ( N/m2) - nb, nC : h s an ton theo gii hn ko , gii hn chy ; Tra t bng XIII.2, XIII.3 [STQTTB-II-356] =1,0, nk = 2,6 , nC = 1,5 ng sut gii hn bn ko l:k

380.10 6 .1,0 146.10 6 N / m 2 2,6 ng sut gii hn bn chy l:

C

240.10 6 .1,0 160.10 6 N / m 2 1,5 t min =k

Chn ng sut sao cho

=146.106 ( N/m2)

3.1.2 Tnh chiu dy thn thp Theo STQTTB-II-360 :

S

Dt .P 2. P

Cm

[STQTTB-II-360]

- Dt : ng knh trong thn thp (m). Theo tnh ton ban u Dt = 0,6m - [k] : ng sut cho php vi loi vt liu chn, N/m2. : H s bn hn ca mi hn dc

Trn thn hnh tr c 2 l ng knh 150mm lp knh quan st cc v tr quan st phn phi cht lng v cht hi lu. V cc l c b tr trn mt ng sinh nn gi tr h s bn ca thn hnh tr c khot lc tnh theo cng thc sau:L L d L 2d L

XIII.16 [STQTTB-II-362]

L: chiu cao thn hnh tr, m L = Ht = 10,1775mL 2d L 10,1775 2.0,15 10,1775 0,97

- P : p sut lm vic trong thp (N/m2)Sv: Phm Th M Hnh Lp LTC-H Ha 5k464

n Ha cng


P

Pmt

Pl

Pmt

g. l .Hl

(N/m2)

- Pmt: p sut ca hi trong thp. Thp lm vic p sut thng nn Pmt = 1 at =9,81.104 (N/m2) - l : Khi lng ring ca cht lng trong thp, kg/m3. Ta ly theo khi lng ring ln nht l khi lng ring trung bnh pha lng on chng v on luyn:l

=

xtbL

xtbC

2

806,01 910,9127 2

858,46 kg/m3

- Hl : Chiu cao ct cht lng trong thp, m. Ta ly chiu cao ln nht l chiu cao thp: Hl = HT = 10,1775 (m) - Pl : p sut thy tnh ca ct cht lng = l.g.H1 - g: Gia tc trng trng: g = 9,81 (m/s2) P = 9,81.104 + 9,81.858,46.10,1775 = 183809,74 (N/m2) - C: S b sung do n mn, bo mn v dung sai v chiu dy, (m) C = C1 + C2 + C3 (m) - C1 : L h s hiu chnh do n mn. B sung do n mn xut pht tiu kinn mn vt liu cathp (m) Chn C1 = 1 (mm) = 10-3 (m) - C2 : H s hiu chnh do bo mn c hc ( m) Thp chng luyn ch cha lng v hi nn t bo mn C2 =0 - C3 : H s hiu chnh do dung sai (m) Tra t bng XIII.9 [STQTTB-II-364] C3 = 0,8.10-3 (m); Vy: C = C1 + C2 + C3 = 10-3 + 0 + 0,8.10-3 = 1,8.10-3 (m) V gi trP 146.10 6 .0,97 183809 ,74 770,47 50 nn ta c th b qua i lng P

mu s ca cng thc tnh chiu dy thit b.S Dt .P 2. C 0,6.183809 ,74 2.146.10 6.0,97 1,8.103

2,189.10 3 (m)

Chun ha S= 3 (mm)


65

n Ha cng


Kim tra ng sut thnh thit b theo cng thc XIII.26 [II-365]th

Dt S C Po 2. S C

C

1,2

p sut th: Po = Pth + Pl (N/m2)[STQTTB-II-366] Trong : Pl : p sut ct cht lng trong thp (N/m2) Pl = g . l . Hl 3 1: Khi lng ring ca nc nhit trung bnh ca thp, kg/mo t tb

tp

tF 3

tw

57,26 65,41 93,79 3

72,15 0 C

Vi nhit trung bnh ca thp nh trn ta ni suy theo bng I.2 [STQTTB-I9]c: 3 1 = 976,3175 kg/m Pl = g . l . Hl = 9,81 . 858,46 . 10,1775 = 85709,74(N/m2) Pth : p sut thu lc (N/m2) Theo bng p sut thu lc khi th [STQTTB-II-358]: Pth = 1,5.P1 = 1,5 . 85709,74 = 128564,61 (N/m2) Po =128564,61 +85709,74 = 214274,35(N/m2) Vy:th

D (S C ) P 2( S C ) h 0C

0,6 (3 1,8).10 3 214274 ,35 2(3 1,8).10 3.0,97 200.10 6 ( N / m)

65,29.10 6

1,2

240.10 6 1,2

Vy St = 3 mm l chp nhn c . 3.2 TNH CHIU DY Y V NP THIT B Chn y v np dng elip c g lp vi thn thit b bng cch ghp bch, tm cc l ly sn phm y v sn phm nh. Vt liu lm y v np bng thp CT3. Chi tit cu to: - y v np elip c g -ng knh: Dt = 0,6 (m)Sv: Phm Th M Hnh Lp LTC-H Ha 5k466

n Ha cng


-Chiu cao g, tra bng XIII.12 [STQTTB-II-385]: h = 25 (mm) Chiu dy ca y v np c xc nh theo cng thc sau: Dt .P D . t C [STQTTB-II-385] S 3,8. . h .k P 2.hb Trong : - [] : ng sut cho php (N/m2) h

: H s bn mi hn = 0,9

- hb: Chiu cao phn li ca y v np, (m). Tra bng XIII.10 [STQTTB-II382] ta c: hb = 150 (mm) - k: H s khng th nguyn k 1 d Dt XIII.48 [STQTTB-II-385]

i vi np thp c ng knh ng dn sn phm nh d = 150mmkn 1 d Dt 1 0,15 0,6 0,75

i vi y thp c ng kn hng dn sn phm y d = 80mmkd 1 d Dt 1 0,08 0,6 0,866

- C: h s hiu chnh (m) 3.2.1 Chiu dy npSn Dt .Pn D . t 3,8. . h .k Pn 2.hbk

C

[STQTTB-II 385]30 nn ta c th b qua i lng

V gi tr

P

k.

h

146.10 6 0,75.0,9 183809 ,74

536,15

P mu s ca cng thc tnh chiu dy np.Sn Dt Pn D . t 3,8. . h .k n 2hb4

C

0,6.183809 ,74 0,6 . 6 3,8.146.10 .0,9.0,75 2.0,15

C

5,89.10

C

Sn

C

5,89.10 4 (m)

0,589(mm) 10(mm) 67


n Ha cng


V vy ta thm vo C: 2mm sao vi i lng b sung phn tnh chiu dy thn thp, ta c: C= 2 + 1,8 =3,8 (mm) Vy Sn = 0,589 + 3,8 = 4,389 (mm) Quy chun ta ly Sn = 5 (mm) Kim tra ng sut np bng nc :St [ D 2 t 2.hb. ( s n c )].P 0 . 7,6k n . h .hb. ( S n C ) 71,69.10 6 ( N / m)C

2.0,15.(5 3.8).10 3 7,6.0,75.0,9.0.15.(5 3.8).10 240.10 6 1,2 200.10 6 ( N / m)

0,6 2

3

.183709 ,74

1,2

Vy Sn = 5 (mm) l chp nhn c. 3.2.2 Chiu dy y thit bS Dt .P . h .k dk

3,8.

Ph

.

Dt 2.hb

C

V gi tr

P

kd .

146.10 6 .0,866.0,9 619,41 30 nn ta c th b qua i 183709 ,74

lng P mu s ca cng thc tnh chiu dy np.Sd Dt .P d 3, 8.4

. C

h

.kd 2.hb Sn C

.

Dt

C

0, 6.1832716

3, 8.146.10 .0, 9.0, 866 2.0,15 0, 508( mm) 10( mm)

.

0, 6

C

5, 08.10

5, 08.10 4 ( m)

V vy ta thm vo C: 2mm so vi i lng b sung tnh phn tnh chiu dy thn thp, ta c: C = 2 + 1,8 = 3,8 (mm) Vy: Sd = 0,5098 + 3,8 = 4,3098 (mm) Chun ha ta c: S = 5 (mm) Kim tra ng sut bng nc :St Dt2 2.hb . S d C .Po C 0, 62 2.0,15. 5 3, 8 .103

.1832713

7, 6.kd . h .hb . Sd 61, 93.106 C

7, 6.0, 866.0, 9.0,15. 5 3, 8 .102 200.106 ( N / m )

1, 2

240.10 6 1, 2


68

n Ha cng


VyS = 5 (mm) l chp nhn c . Vy Sn = Sd = 5 (mm) Tra bng XIII.11 [STQTTB-II-384], vi ng knh Dt = 600mm, S = 5mm, ta tra c khi lng ca y v np: m = 17,5 (kg)

3.3 TNH NG KNH NG DN3.3.1 ng knh ng dn sn phm nh Lng hi nh thp l: gd = 2551,8324 (kg/h) = 0,7088 (kg/s) Nhit ca hi nh thp l: tP = 57,260C Lu lng th tch ca hi nh thp l:d

V

g

: Khi lng ring ca hi nh thp, kg/m

3

M .To 22,4.T M M A .x P (1 xP ).M N 58.0,9383 (1 0,9383).18 55,532.273 2,049 kg / m 3 . 22,4. 273 57,26 g 0,7088 V 0,346(m 3 / s) 2,049

55,532( VC)

Theo bng II.2 [STQTTB-I-370] i vi hi bo ho trong ng dn khi P = 1at ta chn tc hi nh thp: wh = 20 (m/s) [ STQTTB-II -74 ] a. ng knh ca ng dn hi nh thp l:

d

V 0,785.20

0,346 0,785.20

0,148(m) 148(mm)

Quy chun: Dy = 150mm, Dn = 159mm Tc thc t ca hi nh thp l: wTT V 0,785.d 2 0,346 0,785.0,15 2 19,6 (m/s)


69

n Ha cng


b. ng knh ng dn hi lu sn phm nh Lng hi ngng t hi lu l: GR = GP.R = 1635.79.0,595 = 916,0424 (kg/h)=0,2544(kg/s) Nng khi lng ca hi ngng t hi lu: aR = aP = 98% Khi lng ring ca hi ngng t hi lu l: 1R

aPA

(1 a P )N

Ni suy t bng I.2[STQTTB-I-9] nhit tPo = 57,26oCA N

7 49,014(kg / m 3 ) 984,233(kg / m 3 ) 1R R

aPA

(1

aP )N

0,98 749,014

(1 0,98) 984,233

1,3287 .10

3

752,61(kg / m 3 )

Lu lng th tch ca hi ngng t hi lu l:V GRR

0,2544 752,61

0,338.10 3 (m 3 s )

Do sn phm nh t chy v hi lu. Tra bng vn tc II.2 [STQTTB-I-370] w = 0,1 0,5 m/s. Nn ta chn tc hi ngng t hi lu l: wR = 0,3 (m/s) ng knh ca ng dn hi ngng t l:

dR

V 0,785.WR

0,338.10 3 0,785.0,3

0,038(m)

Quy chun: Dy = 40mm, Dn = 45mm Tc thc t ca hi ngng t hi lu l:

wTT

V 0,785.d 2

0,338.10 3 0,785.0,04 2

0,269 (m/s)


70

n Ha cng


3.3.2 ng knh ng dn hn hp u Lng hn hp u vo thp l: F = 4200 (kg/h) = 1,1667 (kg/s) Nhit ca hn hp u: tF = 65,41oCKhi lng ring ca Axeton v nc bng I.2 [STQTTB-I-9] theo t = tF :A

738,6965 (kg/m3)

N

3 980,0245 (kg/m )

Nng khi lng ca hn hp u: aF = 40% Khi lng ring ca hn hp u l:1F

aFA

(1 a F )N

0,4 738,6965

1 0,4 980,0245

F

866,76 kg m 3

Lu lng th tch ca hn hp u l:

V

FF

1,1667 866.76

1,346.10

3

(m3/s)

Chn tc hn hp u l: wF = 0,3 (m/s) ng knh ca ng dn hn hp u l: d V 0,785.WF 1,346.10 3 0,785.0,3 0,076( m) 76( mm)

Quy chun ta c : Dt = 80mm, Dn = 89mm 3.3.3 ng knh ng dn sn phm y a. ng knh ng dn sn phm y Lng sn phm y l: GW = 2564,21 (kg/h) = 0,7123 (kg/s) Nhit ca hn hp y: tw= 93,790C Khi lng ring ca Axeton v Nc c ni suy t bng I.2 [STQTTB-I-9] nhit = two tW A N

93,79 o C 701,073( kg / m 3 ) 962,347 (kg / m 3 ) 1w

aWA

(1 aW )N

0,03 701,073

(1 0,03) 962,347

W

951,707 (kg / m 3 ) 71


n Ha cng


Lu lng th tch ca sn phm y l:V GWW

0,7123 951,707

0,748.10 3 ( m 3 / s )

Chn tc sn phm y l: w = 0,3 (m/s) ng knh ca ng dn sn phm y l:d V 0,785.Ww 0,748.10 3 0,785.0,3 0,056(m) 56( mm)

Quy chun Dt = 60mm, Dn = 69mm b. ng knh ng dn hi lu sn phm y Lng hi sn phm y hi lu l: gtbC = 1637,738 (kg/h) = 0,4549 (kg/s) Nhit ca hi sn phm y hi lu: t W = 93,790C Chn tc hi sn phm y hi lu l: w = 20 (m/s)M hl M A . yW (1 yW ).M N 58.0,3822 (1 0,3822 ).18 33,288.273 M hl .To 0,1,106( kg / m 3 ) hl 22,4.T 22,4.(273 93,79) g1' 0,4549 V 0,41( m 3 / s ) 1,106 hl d V 0,785.Whl 0,41 0,785.20 0,1616 ( m) 162( mm) 33,288( VC)

Quy chun ta c :Dt = 200mm, Dn = 219mm 3.4 TRA BCH Vi thn thp hnh tr lm vic iu kin thng ta chn mt bch lin bng thp CT3 ni thn vi y v np thit b.Theo bng XIII.27 [II-419] Kt qu tng hp bng sau: Py.106 N/m2 0,1 600 740 690 Dt D Db D1 mm 650 611 M20 20 D0 db h Z Ci 20


72

n Ha cng


3.4.1 Chn bch lin bng thp kim loi en ni cc b phn ca thit b v ng. Theo bngXIII.26[STQTTB-II-409] Tn ng dn Dy Dn D D D mm Sn phm nh Hi lu nh ng dn liu Sn phm y Hi lu y 150 40 80 70 200 159 45 89 76 219 260 130 185 185 290 225 100 150 150 255 202 80 128 128 232 M16 M12 M16 M16 M16 16 12 14 14 16 D1 D0 h Z Ci 8 4 4 4 8

3.4.2 Kch thc chiu di on ng ni Da vo ng knh ca cc ng ta tra c s liu sau: Theo bng XIII.32 [STQTTB-II-434] Tn ng dn Dy mm Sn phm nh Hi lu nh ng dn liu Sn phm y Hi lu y 150 40 80 70 200 130 100 110 110 130 Py< 2,5.10-6 N/m2


73

n Ha cng


3.5 LI M, DM M3.5.1 a phn phi cht lng Chn kiu a loi 2 vi cc thng s nh sau: Tra t bng IX.22 [STQTTB-II-230] kt qu c tng hp ti bng sau: ng knh thp 600 ng knh a, Dd mm 350 25 48 3.5.2 Li m Chn ng knh li l: D1 = 590mm Theo bng IX.22 [STQTTB-II-230] chiu rng ca bc b vi m (25 x 25) = 20,5mm 3.5.3 Dm m Chn dm m hnh ch nht c chiu cao bng 2 ln chiu rng. Dm c lm bng vt liu thp CT3, hai u thanh dm c hn vo thn thit b. Tnh bn ca dm:A 2 z

ng knh ng

Bc ng, t

Bc ng, t Chic 24

3.

2 y

, kN/m2

Trong :z

: ng sut php, kN/m2 : ng sut tip, kN/m2

y

- Dm s chu tc dng phn b gy nn bi khi lng ca lp m ca cht lng v ca thnh thit b. - m bo bn cho thanh dm, ta coi cht lng chon y thp. -V khi lng ring ca Nc ln hn ca Axeton nn ta coi thp cha ton Nc. ng thi coi c thp l mt khi tc dng ln mt thanh dm chung. * Th tch ca mt ngn m: Vi Hn: Chiu cao mt ngn m, chn Hn = 0,5mSv: Phm Th M Hnh Lp LTC-H Ha 5k474

n Ha cng


3,14.0,6 2.0,5 0,1413 m 3 Vd 4 4 Theo bng IX.8 [II-193] th khi lng ring ca xp:

.Dt2 .H n

d

= 600 kg/m3

*Khi lng ca mt ngn m: m1

.V

600.0,1413

84,78(kg )

* on Chng c HC = 1,9566m, vi khong cch mi ngn m l 0,5m vy ta phi s dng 3 dm m trong dm trn cng c chiu cao lp m l: HC= 1,9566 2.0,5 = 0,9566m. Th tch ngn m tng ng vi chiu cao m HC l:VdC ' .Dt 2 .H C ' 4 3,14.0.6 2.0,9566 4 0,27 m 3

Vy khi lng ngn m trn cngon Chng l:mC '

.VC'

600.0,27 162(kg )

Vy khi lng ca lp m on Chng l: mC = 2.md1 + mdC = 2.84,78 + 162 = 331,56 (kg) * on Luyn c HL =4,522m, vi khong cch mi ngn m l 0,5m vy ta phi s dng9 dmm trong dm trn cng c chiu cao lpm l: HL= 4,522 8.0,5 = 0,522m. Th tch ngn m tng ng vi chiu cao m HL l:VL' .Dt 2 .H L ' 4 3,14.0,6 2.0,522 4 0,1475 m 3

Vy khi lng ngn m trn cngon Luyn l:

mL'

.VL'

600.0,1475

88,5(kg )

Vy khi lng ca lp m on Luyn l: mL = 8.md1 + mdL = 7.84,78 + 88,5 = 681,96 (kg) Vy khi lng m trong thp chng l: md = mC + mL = 331,56 + 681,96 = 1013,52 kgSv: Phm Th M Hnh Lp LTC-H Ha 5k475

n Ha cng


*Khi lng ca cht lng trong thp: Vi N =962,347 (kg/m3) tra nhit tw o = 93,79o CVthmth

.Dt .H T 4th

2

3,14.062.10,1775 2,87 m 3 4962,347.2,87 2761,93(kg )

.Vth

*Din tch bao quanh thp:S .Dt .H T 3,14.0,6.10,1775 19,174 m 2

* Lc phn b tc dng ln thanh dm ca thnh thit b l:qthepth ep

.S = 7850.19,174 = 150515,9 N/m

- Khi lng ca np bng khi lng ca y: m = 17,5kg * Lc phn b tc dng ln dm ca thit b:q qthep ( md mth Dt m) .g 150515 ,9 (1013,52 2761,93 17,5) .9.81 0,6 212,245 kN / m

* Momen i vi trc x, Mx Mx = MA.MB =q.Dt 2 16 212,245.0,6 2 16 4,77 kN

* Lc ct ngang ti hai u A v B: Qy = RA = RB =q.Dt 16 212,245.0,6 16 63,67 kN

- Biu ni lc :q

l

C A B

Qy Mx


76

n Ha cng


Mt ct nguy him ti B,C,A V trng thi ng sut l n nn ta c: Mx Wx : ng sut cho php ca thp CT3C

240.10 6 N / m 2

240.10 3 kN / m 2

- Wx: Kch thc dm o, m2w Mx 4,77 240.10 3 1,98.10 5 m 22

b.h 2 b. 2b w M: x 6 6 b 0, 031m

4b 3 6

Vy ta chn: b = 40mm, h = 2b = 80mm Vi h l chiu cao, b l chiu rng *Kim tra bn ca thanh dm c b = 40mm, h = 80mm. Theo cng thc:2 z

3.

2 y

, ti v tr 1, 2, 3

Ta c:

max

=QY b.h

min

=

Mx wx

4,77 1,98.10

5

240,9.10 3 kN / m 2 kN/m

2

y max

1,5.

1,5.63,67 0,04.0,082 m ax

29845 ,3

Ti v tr (1):

0

240,9.10 3 kN/m277


n Ha cng


< [ ] => Tho mn iu kin bn Ti v tr (2):h v y 4

6.Q yy

b.h

3

.

h2 4

g20, 08 42

m g

y

0, 08 2 . 3 4 0, 04. 0, 08 62, 4 6.m ax

21965, 76 kN/m2

z

2y

240,9.10 3 2

120,45.10 3126107 ,6kN / m 2

2

z

3

2

(120,45.10 3 ) 2

3.(22383,98) 2

< [ ] => tho mn iu kin bn Ti v tr (3):0 3.2 y

0 3. 21965, 76

2

38045, 8 kN/m2

< [ ] => tho mn iu kin bn Vy chn thanh dm vi thng s: b = 40mm, h = 80mm l t c yu cu thit k.

3.6 GI V TAI TREO 3.6.1 Tai treoChiu cao ca ton thp: HT = 10,1775 Tng khi lng ca ton thp: M = mt + mnap+ mdem + mday + mchatlong + mbx mbx: H s b sung bao gm khi lng cc chi tit ph ca thp nh bch, bulng Khi lng thp: mt = t. Vt Thn thit b lm bng thp CT3 vi -Th tch thp: Vtt

= 7850kg/m3

[STQTTB-II.313]

.( Dn2 Dt2 ) Ht. 4

- Dt, Dn: ng knh trong v ngoi ca thp - Dn = 0,6 + 2.0,003 = 0,606m Dt = 0,6mSv: Phm Th M Hnh Lp LTC-H Ha 5k478

n Ha cng(D 2 n 4 D 2t )

H Cng Nghip H Ni Khoa CN Ha3,14 .(0,606 2 4 0,6 2

Vt

Ht.

10,1775 .

0,0578 m 3

mtM

7850.0,0578mbx

453,815 kg

453,815 17,5 1013,52 17,5 2761,93 mbx

4264 ,265

mbx: Khi lng cc b phn khc, gi thit chn: mbx = 500kg M = 4264,265 + 500 =4764,265kg -Trng lng ca thp l: P = M.g = 4764,265.9,81 = 46737,44 N -Ta s dng 4 tai treo lm bng thp CT3, ti trng ca mi tai treo l:G P 4 46737 ,44 4 11684 ,36

Theo bng XIII.36 [II-438], ta chn tai treo c ti trng cho php l: G = 2,5.104 N. B mt l: F = 173.10-4 m2, ti trng cho php ln b mt l: Q = 1,45.106 N/m2. L B B1 H mm 150 120 130 215 8 60 20 30 s l a d KL 1 tai treo kg 3,48

3.6.2 Gi Tra bng XIII.35 [STQTTB-II-437], ta chn chn c ti trng cho php l: G = 2,5.104 N B mt l: F = 444.10-4 m2, ti trng cho php ln b mt l: Q = 0,56.106 N/m2. L B B1 B2 H mm 250 180 215 290 350 185 16 90 2779

h

s

l

d


n Ha cng


CHNG 4 TNH TON V CHN THIT B PH4.1 THIT B GIA NHIT HN HP U Thit b trao i nhit loi ng chm thng ng vi cc thng s: - Chiu cao ng: h0 = 1,5 (m) - ng knh ng: d = 30 (mm) - Chiu dy thnh ng: = 2,0 (mm)

Vy ng knh trong ca ng l: d0 = 26 (mm) - Dung dch i trong ng, hi t i ngoi ng - Chn vt liu ch to ng l thp khng g CT3 Vy h s dn nhit ca vt liu l: = 50 (W/m.) [STQTTB-II-313]

Chn hi t l hi nc bo ho p sut 2 at, c t0 si = 119,620C 4.1.1 Hiu s nhit trung bnh Nhit vo ca dung dch l: td =250C Nhit ra ca dung dch l: tc = tF = 65,410C Hi t l hi nc bo ho nn nhit khng thay i v l nhit si p sut chn ( 2 at ): 119,620C [STQTTB-I-314]t tc 119,62 25 94,62 o C 119,62 69,2 54,21o C ttb

tc t tc

ln

94,62 54,21 94,62 ln 54,21

72,16 o C

Suy ra nhit trung bnh hn hp u ttb2 =119,62 72,16=47,46oC 4.1.2 Lng nhit trao i Q=FCP(tF tf) CA = 2264,245(J/kg ) CN = 4180,60(J/kg )Sv: Phm Th M Hnh Lp LTC-H Ha 5k480

[STQTTB-II-46]

T bng I.153[STQTTB-I-171] ni suy ti 47,46oC ta c :

n Ha cng


CP aF CA (1 aF )CN 0,4.2264,245 (1 0,4).4180,605 3414,055 (J/kg )Q = FCP(tF tf) = 4200.3414,055(65,41 25)= 579440242,71(J/h) = = 160955,62 (J/s) 4.1.3 Din tch trao i nhit

2

th t1 tT1 q11

qT tT2 tdd tT t2

q2

K hiu: th : Nhit hi t hi nc bo ho 2 at (oC) : th = ttb1 = 119,62 oC tT1 : Nhit mt ngoi ng (oC) tT2 : Nhit mt trong ng (oC) tdd : Nhit dung dch (oC) : tdd = ttb2 = 47,46oC t1 : Hiu nhit gia hi t v mt ngoi ng (oC) : t1 = th tT1 t2 : Hiu nhit gia mt trong ng v dung dch (oC) : t1 = tT2 tdd tT : Hiu nhit gia mt ngoi ng v mt trong ng (oC): tT = tT1 tT2 : Chiu dy thnh ng (m) tm : Nhit mng nc ngng (oC) : tm = 0,5.( th + tT1) q1 : Nhit ti ring pha hi ngng t (W/m2) q2 : Nhit ti ring pha dung dch (W/m2) 1 : H s cp nhit pha hi ngng t (W/m2.) 2 : H s cp nhit pha dung dch (W/m2.)Sv: Phm Th M Hnh Lp LTC-H Ha 5k481

n Ha cng


a. H s cp nhit pha hi ngng t4

2,04. A. Trong :

r (W/m.) V.101 [STTBQT-II-28] t1 .H

- r: n nhit ngng t ly theo tobh-

t1 :chnh lch nhit gia hi bo ha v thnh ngoi ng

- H: chiu cao ng = 1,5 m - A: h s tra theo tom ( nhit mng nc ngng)o Vi t hd

119,62 o C ni suy theo I.212 [STTBQT-I-254] 526,247(kcal / kg )2,15 o C

r

2203290 ,94 J kg

Gi s: t1 Khi tm

119, 62

2,15 118, 545o C 2

T tom = 118,545oC tra theo [STQTTB-II-29] ta c A=187,3454

Vy

1

2, 04. A.

r t1.H

4

2, 04.187, 345.

2203290, 94 2,15.1, 5

10987, 7 (W/m2. )

b. Tnh h s cp nhit pha hn hp chy xoy0 , 25 2

0,021 . k .Re

0,8

.Pr

0, 43

Pr P rt

Chn d = 30x2 mm , H= 1,5 m

H d

1, 5 0, 026

57, 69 50

k

1

Re : Chun s Reynolt: qu trnh truyn nhit t hiu qu, dung dch phi ch chy xoy Gi s Re = 10500


82

n Ha cng


Chun s Pr: Chun s Prand ca dng tnh theo nhit dng:Pr CP .

V.35 [STQTTB-II-12]

Trong : CP : Nhit dung ring ca dung dch ttb, (J/kg. ) = 3414,055 (J/kg. ) : nht ca dung dch totb , (N.s/m2) Ti totb = 47,46oC ni suy theo I.101[I-91]A N

0,25159 .10 3 ( N .s m 2 ) 0,576178 .10 3 ( N .s m 2 ) xF .lg (1 xF ) lg 0,1714 .lg 0,25159 .103

lghh

hh

A

N

1 0,1714 .lg 0,576.11780

3

0,5.10 3 ( N .s m 2 )

-

: H s dn nhit ca hn hp, (W/m.)

Cng thc tnh h s dn nhit:3

A.C P .

M

I.32 [STQTTB-I-123]

Trong : A: H s ph thuc mc lin kt ca dung dch Axeton - Nc.V Axeton v Nc l hai cht lng lin kt nn A = 3,58.10-8 [STQTTB-I-123] : Khi lng ring ca dung dch (kg/m3) Tra t bng I.2[STQTTB-I-9] ti ttb= 47,46oC ta c:A N

7 59,794(kg / m 3 ) 9 88,643(kg / m 3 )

Nng khi lng ca dung dch: aF = 40% Theo IX .104a [STQTTB-II-183], ta c:1hh hh

aFA

aF ) (1 N

0,4 759,794

1 0,4 988,643

1,13335 .10

3

882,34 kg m 383


n Ha cng


M: Khi lng mol phn t ca dung dch, (kg/kmol)=24,856 (kg/kmol)3

3,58.10 .3414,055.882,34

8

882,34 24,8563

0,402 (W/m )

Vy: Pr

CP .

3414,055.0,5.10 0,402

4,2463

Chun s Prt: Chun s Prand tnh theo nhit tng:Prt C Pt .t t

- Nhit ti ring v pha hi ngng t : q11

. t1 10987, 7.2,15

23623, 56(W / m2 )

-hiu s nhit hai pha thnh ng :

tt rt

tT 1 rT 1

tT 2 rT 2

qt

rt[STQTTB-II-3]

: b dy ca thnh =2 mm : h s dn nhit ca vt liu lm ng (W/m ) Theo bng[STQTTB-II-313] vi thp CT3 thrT 1 =1,16.10 (m . /W)-3 2

= 50(W/m )

Tra theo bng PL 12 tnh ton qu trnh thit b tp 1 [STQTTB-I-346]

rT 2 =0,464.10-3 (m2/W)rt 1,16.10 tt3

0,464.10

3

0,02 503

2,024.10

3

Do

23623, 56.2, 024.10

47, 8o C

tT1 = th - t1 = 119,62 2,15 = 117,47(oC)tT 2 tT 1 tt 117, 47 47, 8 69, 67 o C


84

n Ha cng


t2 tT 2 ttb 2 69,67 47,46 22,21Tnh CPt: Ti tT2 = 69,67oC ni suy theo I.153[I-171] CA = 2336,43(J/kg ) CN = 4190(J/kg )C Pt C A aF (1 a F )C Nt

2336,43.0,4

(1 0,4)4190

3448,572 (J/kg )

Tnh

:

Ti tT2 = 69,67oC ni suy theo I.2[I-9]A B

732,9( kg / m 3 ) 977,68( kg / m 3 ) aFt A V

1 aF

0,4 732,9

1 0,4 977,68

862,46( kg / m 3 )

Tnh t: Ti tT2 = 69,67oC ni suy theo bng I.101[STQTTB-I-91]A N

0,215.10 3 ( N .s / m 2 ) 0,415.10 3 ( N .s / m 2 ) lgt t

x F lg

A 3

(1

x F ) lg

N

0,1714 lg 0,215.10

3

(1 0,1714 ) lg 0,415.10

3

0,37076 .10

Tnh

t

:

Theo [STQTTB-I-123] :3 t

A.C Pt .

t t

M

, (W/m.)862,46 24,8563

t

3,58.10 8.3448,572.862,46.3 C Pt .t

0,347

Vy: Prt

t

3448,572.0,37076 .10 0,3470,8 0, 43

3,6850 , 25

2

0,021 .

d

Re

Pr

Pr . P rt


85

n Ha cng0 , 25


4,2463 0,402 0,021. .10500 0,8.4,2463 0, 43. 3,685 0,026q22

1032,43

. t2

1032,43.22,21

22930 ,27( W / m 2 )

q1 q1

q2

23623,56 22930 ,27 23623,56

0,03

5%

Vy chn t1

2,15 o C l ph hp

Kt qu chp nhn c Nhit ti ring trung bnh:qtb q1 2 q2 23623,56 2 22930 ,27 23276 ,64 (W/m )2

4.1.4 B mt truyn nhitF Q qtb 160955 ,62 23276 ,64 6,915(m 2 )

4.1.5 S ng truyn nhitn F d td H 6,915 0,026 0 ,03 3,14. .1,5 2 52,43

(ng)

Quy chun ta c n = 61 (ng ) t bng V.11 [STQTTB-II-48] Chn cch sp xp ng theo hnh lc gic, gi a l s ng trn mt cnh hnh lc gic.b n 2a 1 3a (a 1) 1 61 a a 5 4

Chn a = 5(ng)

S ng trn ng cho hnh lc gic: b = 2a 1 = 9ng

4.1.6 ng knh trong ca thit bng knh ngoi ca ng: dn = 0,03m t l bc ng, t = (1,2 S ng xuyn tm b= 9 Theo [STQTTB-II-49] ng knh trong ca thit b l:Sv: Phm Th M Hnh Lp LTC-H Ha 5k486

1,5).dn

Chn bc ng l: t = 1,5.dn = 1,5.0,03 = 0,045m

n Ha cng


Dt = t.(b - 1) + 4.dn= 0,045.(9 1) + 4.0,03 = 0,48m 500mm

4.1.7 Tnh li vn tc v chia ngnVn tc thc t :t

4.G F .d 2 .n.

4.4200 3,14.0,026 2.61.882,34.3600

0,041(m / s )

Vn tc gi thitgt

Re. d.

10500 .0,5.10 3 0,026.882,34gt t

0,2288(m / s )

S ngn m

0,2288 0,041

5,6

ngn

Quy chun, ta chia thit b lm: m= 6 ngn Vy cc thng s ca thit b gia nhit hn hpu l: F = 6,915 m2 L = 1,5 m dn =30 mm D = 500 mm n = 61 ng m = 6 ngn

4.2 TNH THNG CAO V4.3.1 Cc tr lc trong qu trnh tip liu p sut ton phn cn thit khc phc tt c sc cn thy lc trong h thng k c ng dn vo thit b khi dng chy ng nhit.

P

P

Pm

PH

Pc

Pk

Pt ( N / m 2 ) [STQTTB-I-376]

Trong : - P : p sut ng lc hc cn thit to tc cho dng chy ra khi ng dn, N/m2.2

P

2

[STQTTB-I-377]87


n Ha cng


-

: khi lng ring ca cht lng trong ng, kg/m3. : tc dng chy, m/s.Pm: p sut khc phc tr lc ma st khi dng chy n nh trong ng

thng, N/m2.Pm . L d tb2

2

.

L . P [STQTTB-I-377] d tb

-

: h s ma st

- L : chiu di ng ni (m) - dt : ng knh tng ng ng dn (m) - Pc : tn tht p sut cc b (N/m2)2

Pc

2

[STQTTB-I-377]

Vi: - : h s tr lc cc b - PH : p sut cn thit nng cht lng ln cao hoc khc phc p sut thy tnh . PH .g.H ( N / m2 ) [I-377]

- H: Chiu cao cht lng, m - Pt : p sut cn thit khc phc tr lc trong thit b - Pk : p sut b sung cui ng dn trong nhiu trng hp Trong tnh ton thit b chng luyn vi thp m th:Pt , Pk

a. Tr lc ca on ng t thit b gia nhit hn hp u n thp2

Tnh p sut ng hc: P

2

Khi lng ring ca dung dch ti tos = tF = 65,41oC trong phn tnh ton c kh tnh = 866,76(kg/m3) d = 100mm ( ng knh ng dn liu, tnh trong phn tnh ton c kh )Sv: Phm Th M Hnh Lp LTC-H Ha 5k488

n Ha cng


Tc trung bnh ca lu th:4.V .d 2 .36002

4.F .d . .36002

4.4200 3,14.0,1 .866,76,5.36002

0,168 m / s

P

2

866,76.0,168 2 2

12,51( N / m 2 )

Tnh p sut khc phc tr lc ma st:. L Pm = . . d td 22

= .

L . Pd, N/m2 d td

Chn chiu di ng dn: L = 2,5m ng knh tng ng ca ng: dtd = d = 100mm = 0,1m Re Chun s Re ca lu th : .d .

nht ca hn hp ti toF = 65,41oC Ni suy theo bng I.101 [STQTTB-I-91] ta c:A N

0,2219 .10 3 ( N .s / m 2 ) 0,4387 .10 3 ( N .s / m 2 ) lg hh xF .lg A (1 xF ) lg3

N 3 hh

0,1714 .lg 0,2219 .10.d .

(1 0,1714 ) lg 0,4387 .10

0,39.10 3 ( N .s / m 2 )

Re

0,168.0,1.886,765 0,39.10 3

38198 ,89

10 4

Vy dng chy trong ng l dng chy xoy Chn ng lm bng ng trng km mi bnh thng. Tra bng II.15 [STQTTBI381] ta c

0,1 0 ,5 mmd td 0,1 0,1.103

Chn1000d td8 7

=0,1mm

Vy: Re gh

6.

6.1000 8 7

16096 ,17


89

n Ha cng98


Re n

220.

d td

220.1000 9 8

521702 ,22

Ta thy Regh< Re < Ren v vy h s ma st c tnh theo cng thc sau:0,1. 1,46. 100 Re3 0 , 25

d td

[STQTTB-I-380]100 54497 ,80 , 25

0,1.10 0,1. 1,46. 0,1Pm . L . P d tb

0,024

0,062.

2,5 2 .1,512 19,39( N / m ) 0,1

Tnh tr lc cc b:PC . . 22

PC

. Pd , N/m2

- : H s tr lc cc b Trn ng c : + Mt van chn tiu chun, m hon ton. Theo bng II.26 [I-397] ta c:1

4,4

+ Tr lc ca 3 khuu 90o do 3 khuu 30o to thnh. Chn a/b =1. T bng II.26 3.0,3 0,9 [STQTTB-I-394] 2 +Tr lc ra khi ca ng, t m: Fo Ft3

0,1 0,6 0,6966

0,1667

1

do_an_hoa_cong 2011

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