nguyenlyhoacongnghiep

8/14/2019 NguyenLyHoaCongNghiep

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MN HC

NGUYN L HA CNG NGHIP

30 tit (15 LT + 7,5 BT + 7,5 TH)

TI LIU THAM KHO

1. J.P. MOULIN, Gnie des procds, tp 1 & 2, Technip, 1999.2. Vn i - Nguyn Trng Khun - Trn Quang Tho - V Th Ngc Ti

- Trn Xoa, C scc qu trnh v thit b cng ngh ha hc, Tp 1 & 2,

Nh xut bn i Hc v Trung hc chuyn nghip

3. P. TRAMBOUZE - H. VAN LANDEGHEM - J.P. WAUQUIER, Lesracteurs chimiques, Technip, 1984.

4. V B Minh, K thut phn ng, Trng i Hc Bch Khoa TP. H ChMinh, 1999.

5. R.E TREYBAL, Mass transfer operations, 1980.


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Nguyn l ha cng nghip 2

NI DUNG MN HC

L thuyt v bi tp

Chng I: Mu

Chng II: Chng luyn

Chng III: Trch ly

Chng IV: Thit b phn ng Bi tp p dng

Chng V: Thit b trao i nhit

Thc hnh

Vn dng phn mm PROII m phng mt s s trong cng

nghip ha hc


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MC LCCHNG 1:MU................................................................................................................. 5

1.1. PHNLOICCQUTRNHTRONGCNGNGHHAHC ........................... 5

1.2. NHNGKINTHCCBNCAQUTRNHCHUYNKHI......................... 61.2.1.nh ngha ..................................................................................................................... 61.2.2. Phn loi ....................................................................................................................... 6

CHNG 2:CHNG LUYN................................................................................................... 72.1. NHNGHACHNG .................................................................................................. 72.2. PHNLOICCPHNGPHPCHNG............................................................... 72.3. PHNLOIHNHPHAICUT.......................................................................... 82.4. CNBNGLNGHICAHNHP2CUT................................................... 9

2.4.3. Gin ng nhit P-x-y .............................................................................................. 92.4.4. Gin ng p T-x-y................................................................................................. 102.4.5. Gin phn mol x-y .................................................................................................. 11

2.5. THPCHNGLUYN ............................................................................................... 122.5.1. Nguyn tc hotng.................................................................................................. 122.5.2. Thit b ngng tnh thp (Condenser) .................................................................... 132.5.3. Thit bun si y thp (Reboiler)............................................................................ 142.5.4. Cn bng vt cht........................................................................................................ 162.5.5. Xc nh chshi lu rfv sa l thuyt ti thiu Nmin......................................... 172.5.6. Xc nh sa thc tNTT.......................................................................................... 19

THC HNH

VN DNG PHN MM PROII M PHNG MT S S TRONG CNG

NGHIP HA HC

I- GII THIU TNG QUAN ..................................................................................................... 211-MC CH, VAI TR CA THIT K M PHNG ........................................................................... 212-CC PHN MM M PHNG TRONG CNG NGH HA HC.......................................................... 22

II- PHN MM PRO/II ............................................................................................................... 221-LNH VC S DNG................................................................................................................... 222-QU TRNH M PHNG BNG PHN MM PRO/II....................................................................... 23

III- L THUYT NHIT NG HC........................................................................................ 24IV- CSLA CHN M HNH NHIT NG.................................................................... 25V- CC PHN CBN CA PROII......................................................................................... 28

1-GIAO DIN CA PROII-QUI C BAN U ............................................................................... 282- Ca sPRO/II ................................................................................................................... 29

VI- CC THAO TC THNG DNG TRONG M PHNG BNG PRO/II........................ 301-MMT CHNG TRNH M PHNG MI (OPENING ANEW SIMULATION) ................................ 302-MMT CHNG TRNH M PHNG C (OPENING AN EXISTING SIMULATION) .................. 303-GHI MT FILE M PHNG ANG HIN HNH (SAVING THE CURRENT SIMULATION).................. 30

a- Ghi mt file m phngang hin hnh ............................................................................. 30b- Ghi mt file m phng vi mt tn khc ........................................................................... 31

4-XA MT CHNG TRNH M PHNG (DELETING A SIMULATION)........................................... 315-SAO CHP MT CHNG TRNH M PHNG (COPY A SIMULATION).......................................... 31


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6-THAY I DNG NG VIN CC DNG (MODIFYING THE FLOWSHEET STREAM BORDERSTYLE)........................................................................................................................................ 327-HIN TH TNH CHT CA DNG TRN S M PHNG ............................................................ 328- S DNG FLASH HOT-KEY TOOL............................................................................................ 33

9-XUT MT S M PHNG RA CA S LU TR TM (EXPORTING THE PFD TO THE WINDOWSCLIPBOARD) ............................................................................................................................... 3410-NHP MT FILE PRO/II C SN (IMPORTING A PRO/IIKEYWORD INPUT FILE)...................... 3411-XC NH CC TNH CHT V CN BNG LNG - HI CA CC H2 CU T(DISPLAY BVLE).. 34

VII- BI TP P DNG............................................................................................................ 36BI TON 1:M PHNG S CNG NGH CA PHN XNG TCH MTHANE ........................... 36BI TON 2:M PHNG THIT B TCH KH - LNG ...................................................................... 38BI TON 3:TNH NHIT SI CA MT HN HP HAI PHA MT P SUT NHT NH.................. 39BI TON 4:M PHNG THP TCH PROPANE ............................................................................ 40BI TON 5:XC NH A NP LIU TI U CHO THP TCH PROPANE BNG CNG COPTIMISER................................................................................................................................................... 42BI TON 6:XC NH SA L THUYT TI THIU V CH S HI LU TI THIU CHO THP TCHPROPANE BNG PHNG PHP SHORTCUT ................................................................................... 44

CHNG 3:TRCH LY ........................................................................................................... 463.1. NGUYN TC ................................................................................................................... 463.2. S .............................................................................................................................. 463.3. NG DNG ...................................................................................................................... 46

CHNG 4:THIT B PHN NG....................................................................................... 474.1. ICNG................................................................................................................. 47

4.1.1. PHN LOI THIT BPHNNG........................................................................... 47a- Theo pha ca h ................................................................................................................ 47b-iu kin tin hnh qu trnh............................................................................................ 47c- Theo iu kin thy ng................................................................................................... 474.1.2. PHN LOI CC THIT BPHNNG THEO PHNG THC LM VIC ...... 48a- Thit b phn ng gin on :........................................................................................... 48b- Thit b phn ng lin tc : ............................................................................................... 49c- Thit b phn ng bn lin tc : ........................................................................................ 504.1.3. NHIM VTHIT KTHIT BPHNNG.......................................................... 50

4.2. CNBNGVTCHTVCNBNGNHITTNGQUT ............................. 514.2.4. Cn bng vt cht........................................................................................................ 514.2.5. Cn bng nhit ............................................................................................................ 51

4.3. MTMTSDNGTHITBPHNNGNGTHCBN.................... 52Thit b phn ng lin tc...................................................................................................... 52a- Thit b phn ng dngng : ............................................................................................ 52b- Thit b phn ng dng khuy trn l tng..................................................................... 55c- Thit b phn ng nhiu ngn (tag) ............................................................................... 59

4.4. PDNGPHNGTRNHTHITK..................................................................... 604.4.7. SO SNH CC THIT BPHNNGN ............................................................. 604.4.8. HNHIU THIT BPHNNG............................................................................. 67


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CHNG 1: MU

1.1. PHN LOI CC QU TRNH TRONG CNG NGHHA HC

Nhn chung cc qu trnh trong cng ngh ha hc c phn thnh 4 loi sau:

1. Cc qu trnh chc: gm cc qu trnh: p, nghin, sng, cc vt liurn.

2. Cc qu trnh thu lc: nghin cu v: Cc nh lut v thy tnh, thy ng, chuyn ng ca cht lng, cht kh. Cc thit b vn chuyn kh, lng (bm, qut, my nn, ) Cc phng php v thit b phn ring cc h kh, lng khng ng nht (lng,lc, ly tm, )

3. Cc qu trnh nhit: nghin cu v: Cc nh lut v truyn nhit (dn nhit, cp nhit, bc x nhit, ) Cc qu trnh v thit b trao i nhit (un nng, lm ngui, ngng t, c c) Cc qu trnh lm lnh.4. Cc qu trnh chuyn khi: nghin cu v: Cc nh lut v s di chuyn vt cht gia cc pha vi nhau Cc thit b chuyn khi (chng luyn, hp th, hp ph, sy, trch ly, kt tinh,)


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1.2. NHNG KIN THC CBN CA QU TRNH CHUYN KHI

1.2.1. nh ngha

- L qu trnh di chuyn vt cht t pha ny sang pha khc khi hai pha tip xctrc tip vi nhau;

- y l qu trnh ng vai tr quan trng trong nn cng nghip ha hc v c,hu c, lc ha du, thc phm,

1.2.2. Phn loi

Tu theo c trng ca s di chuyn vt cht v tnh cht ca 2 pha phn loi:

- Chng: l qu trnh tch cc hn hp lng thnh cc cu t ring bit, trong vt cht di chuyn t pha lng vo pha hi v ngc li. y l qu trnh rt ph

bin (qu trnh chng ct cn, chng ct du th, )

- Hp th: l qu trnh vt cht di chuyn t pha kh vo pha lng (iu ch olumbng cch cho H2SO4m c h p th kh SO2; tch kh acide bng dung dch

alkanolamine);

- Hp ph: l qu trnh vt cht di chuyn t pha kh vo pha rn (tch kh acidera khi hn hp kh t nhin hay kh ng hnh bng ry phn t);

- Trch ly: l qu trnh tch hon ton hay mt phn cht ha tan trong cht lnghay cht rn bng mt cht lng khc;

- Kt tinh: l qu trnh tch cht rn trong dung dch, trong vt cht di chuynt pha lng vo pha rn (kt tinh ng, kt tinh phn ln, );

- Sy kh: l qu trnh tch nc ra khi vt cht m, trong vt cht (hi nc)di chuyn t pha lng hay pha rn vo pha kh (sy nng sn thc phm);

- Ha tan: l qu trnh vt cht di chuyn t pha rn vo pha lng (ha tan muihoc ng vo nc);


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CHNG 2: CHNG LUYN

2.1. NH NGHA CHNG

- L phng php dng tch cc hn hp cht lng cng nh cc hn hp khlng thnh cc cu t ring bit da vo bay hi khc nhau ca cc cu t

trong hn hp;

- Trong trng hp n gin nht th chng v c c gn nh nhau, nhng giachng c mt ranh gii cbn:

Chng: Dung mi v cht tan u bay hi; C c: Ch c dung mi bay hi cn cht tan khng bay hi;

- Khi chng thu c nhiu sn phm v thng c bao nhiu cu t ta scby nhiu sn phm;

- i vi trng hp 2 cu t : sn phm nh gm cu t c bay hi ln + cu t c bay hi b; sn phm y gm cu t c bay hi b + cu t c bay hi ln;

2.2. PHN LOI CC PHNG PHP CHNG

Trong sn xut, thng gp cc phng php chng sau:

1. Chng n gin:

- dng tch cc hn hp gm cc cu t c bay hi rt khc nhau- thng dng tch sb v lm sch cc cu t khi tp cht2. Chng bng hi nc trc tip:

- dng tch cc hn hp gm cc cht kh bay hi v tp cht khng bay hi


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- thng c ng dng trong trng hp cht c tch khng tan vo nc3. Chng chn khng: Dng trong trng hp cn h thp nhit si ca cut (i vi cc cu t trong hn hp d b phn hunhit cao hay c nhit si qu cao)

4. Chng luyn:- L phng php ph bin nht dng tch hon ton hn hp cc cu t d bay

hi c tnh cht ha tan mt phn hoc ha tan hon ton vo nhau;

- Chng luyn p sut thp dng cho cc hn hp d b phn hunhit cao;- Chng luyn p sut cao dng cho cc hn h p khng ha lng p sut

thng;

2.3. PHN LOI HN HP HAI CU T

1. Dung dch l tng:

- l dung dch m trong lc lin kt gia cc phn t cng loi v lc lin ktgia cc phn t khc loibng nhau.

- Khi cc cu t ha tan vo nhau theo bt c t l no. cn bng lng-hi honton tun theo nh lut Raout;

2. Dung dch thc:

- L nhng dung dch hon ton khng tun theo nh lut Raout;- S sai lch vi nh lut Raout l dng nu lc lin kt gia cc phn t khc

loi < lc lin kt gia cc phn t cng loi;

- S sai lch vi nh lut Raout l m nu lc lin kt gia cc phn t khc loi> lc lin kt gia cc phn t cng loi;

- Trng hp lc lin kt gia cc phn t khc loi


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Ta xt trng h p ph bin nht:

cht lng ha tan vo nhau theo bt

ct l no

2

1

3

Hnh 2-1: Quan h gia p sut v

thnh phn ca dung dch 2 cu t

1. Tun theo nh lut Raout;2. Sai lch dng3. Sai lch m

2.4. CN BNG LNG HI CA HN HP 2 CU T

2.4.3. Gin ng nhit P-x-y

P0A

Hi

Lng - Hi

Lng

T = constP

PM

P0B

0 xM yM 1

Trong :

A : cu t d bay hi P0A > P0B


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Nguyn l ha cng nghi p

xM, yM: thnh phn ca cu t A trong pha lng v pha hi nhit T v p sut

PM

Thnh phn ca cu t B trong pha lng v pha hi nhit T v p sut PMl: 1-xM, 1-yM

Biu ny t s dng v trong thc t P rt t thay i

Sdng biu T-x-y

2.4.4. Gin ng p T-x-y

T P = const

T0B

T0A

AB

Lng - Hi

Hi

Lng

TM

xM yM

Trong :

A : cu t d bay hi T0A < T0B

xM, yM: thnh phn ca cu t A trong pha lng v pha hi Pv TM

thnh phn ca cu t B trong pha lng v pha hi nhit T v p sut PM l:

1-xM, 1-yM


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2.4.5. Gin phn mol x-y

V d ta c gin phn mol x-y ca h 2 cu t Propane v Butane. Trong :

Trc x : biu din phn mol ca cu t nh Propane trong pha lng ; Trc y : biu din phn mol ca cu t nh Propane trong pha hi.

90

90


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2.5. THP CHNG LUYN

2.5.1. Nguyn tc hot ng

Thp chng luyn gm c 2 on :

on luyn : L phn trn, gm ta tip liu trln nh ;

on chng : L phn di, gmta tip liu trxung di;

Thp chng luyn gm c nhiu a

Trn mi a xy ra qu trnh

chuyn khi gia pha lng v pha hi.

Pha hi i t di ln qua cc l ca

a xuyn qua pha lng i t trn

xung theo cc ng (vch) chy

chuyn.

V nhit trong thp cng ln cao cng gim nn khi hi i qua cc a t di

ln, cc cu t c nhit si cao s ngng t li v cui cng trn nh thp, ta

s thu c hn hp sn phm gm hu ht l cc cu t nh (d bay hi). Hi ny

si vo thit b ngng t (condenser) (mt phn hoc hon ton) nh thp

hi lu lng ngng tc v li thp v ly ra lm sn phm nh.

Ngc li, pha lng i t trn xung gp hi c nhit cao hn, mt phn cu t

c nhit si thp s bc hi nng ca cu t nng (kh bay hi) trong pha

lng s cng tng v cui cng y thp, ta s thu c hn hp sn phm gm

hu ht l cc cu t nng. Mt phn sn phm y si vo thit bun si li

(reboiler) y thp to mt lng hi a vo ty thp, m bo trong thp

lun lun c s tip xc gia 2 pha lng v hi.


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Qu trnh bc hi v ngng t lp

li nhiu ln cc a

Pha hi i ln cng giu cu t nh

Pha lng i xung cng giu cu t

nng

Theo l thuyt Mi a l mtbc thay i nng : thnh phn hi

khi ri khi a cn bng vi thnh

phn lng khi i vo a sa = s

bc thay i nng .

Thc t trn mi a qu trnh chuyn khi gia 2 pha thng khng t cnbng Sa thc t > sa l thuyt

Hiu sut aTT

LT

N

N==

tthcaS

thuytlyaS

2.5.2. Thit b ngng tnh thp (Condenser)

c 4 dng Condenser :

1. Partial (ngng t mt phn): Hi i ra tnh thp c lm lnh v ch ngngt mt phn. Loi Condenser ny thc s l mt bc thay i nng . Nhit

trong Condenser chnh l nhit im sng ca hn hp hi cn bng.

Gm 2 loi :

- loi Distillat vapor : lng ngng t ch hi lu vnh thp, cn snphm ly ra th hi c gi l Overhead.


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- Loi Distillat mixe : lng ngng t mt phn hi lu vnh thp, cnli ly ra lm sn phm sn phm nh gm 2 loi l sn phm hi v

sn phm lng.

2. Bubble Temperature : Hi i ra tnh thp c lm lnh n nhit imsi ca hn hp v ngng t hon ton, mt phn cho hi lu vnh thp, phn

cn li ly ra dng sn phm lng, c gi l Fixe Rate Draw.

Lon

Hi

Long

Hi

a- Dng Partial

Distillate vapor Distillate mixe

b- Dng Bubble

2.5.3. Thit bun si y thp (Reboiler)

c 4 dng Reboiler :

- Thermosiphon without baffles v with baffles- Dng Kettle : c mc nh (qui chun)- Dng one through- Dng l


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Trong , loi Thermosiphon gm 2 loi: without baffles v with baffles.

t c cht lng sn phm y cao hn, ngi ta thit k loi

Thermosiphon with baffles c cu to nh sau:


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210

300

?

?

?

?

50

2.5.4. Cn bng vt cht

Nu gi :

F - Lng hn hp nguyn liu i vo thp, kg/h

P - Lng sn phm nh, kg/h

W - Lng sn phm y, kg/h

aF, aP, aW : nng % khi lng ca cu t d bay hi trong hn hp nguyn liu,

trong sn phm nh v trong sn phm y.Phng trnh cn bng vt cht ton thp : F = P + W

Nu i vi cu t d bay hi : F.aF = P.aP + W.aW

Ta tnh c P :WP

WF

aaaa

FP

= W = F P


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Chuyn t nng % khi lng sang nng phn mol :

B

F

A

F

A

F

MM

M

a1a

a

xF += B

P

A

P

A

P

MM

M

a1a

a

xP += B

W

A

W

A

W

MM

M

a1a

a

xW +=

Vi MA, MB: khi lng mol ca cu t nh v cu t nng

Tnh khi lng mol trung bnh ca:

hn hp nguyn liu: MF = xF.MA +(1-xF).MB sn phm nh: MP = xP.MA +(1-xP).MB sn phm y: MW = xW.MA +(1-xW).MBLp bng cn bng vt cht ton thp:

Hn hpNng %

khi lng

Nng phn

mol

Lu lng khi

lng, kg/h

Lu lng

mol, kg/h

Nguyn liu aF xF F FM

F

Sn phm nh aP xP PPM

P

Sn phm y aW xW WWM

W

2.5.5. Xc nh ch s hi lu rfv sa l thuyt ti thiu Nmin

Ch s hi lu rf l t s gia lng lng hi lu v lng sn phm nh.

xc nh ch s hi lu rfv sa l thuyt ti thiu Nmin, ta thc hin theo

nhng bc sau:


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1- Xc nh rf min:F

*F

*FP

minf xyyx

r

=

Vi y*F - nng phn mol cn bng ng vi xF

2- Xc nh cc gi tr rf= b. rfmin vi b = 1,2 2,5

3- Xc nh cc gi tr1r

xB

f

P

+=

4- Trn ng cn bng lng hi x-y ca h hai cu t Vng lm vic ca:

- on luyn: bng cch ni im (xP, yP) vi im (0, B)

- on chng: bng cch ni im (xW, yW) vi giao im ca ng lm

vic ca on luyn vi ng x = xF (nu hn hp nguyn liu vo im si)

5- Xc nh s bc thay i nng NLT bng cch v cc ng thng song song

vi trc honh v trc tung bt u tim xP cho n khi qu im xW. NLT thng

thng khng phi l s nguyn.

6- Gi tr thch hp ca ch s hi lu rfv sa l thuyt ti thiu Nmin tng ngvi gi tr cc tiu ca NLT(rf+ 1)

b

rf

B

NLT

NLT(rf+ 1)


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xP

ng lm vic on luyn

ng lm vic on chng

B = xP/(Rx+1)

xW xF

2.5.6. Xc nh sa thc t NTT

Sa thc t:tb

LTTT

NN

=

3WFP

tb++

=

Vi : P, F, W - hiu sut ca a u tin nh thp, ca a np liu v ca a

cui cng y thp.

Hiu sut a l mt hm ca bay hi tng i v nht ca cht lng:

( )= ,f


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Trong : - bay hi tng i ca hn hp

- nht ca hn hp lng, N.s/m2

bay hi tng i ca cc hn hp thc c xc nh theo cng thc:

x

x1

y1

y

=

y, x : nng phn mol ca cu t d bay hi trong pha hi v pha lng

Sau khi tnh c tch ( , ) Tra th Correlation de OConnel xc

nh c P, F, W xc nh tb NTT


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THC HNH

VN DNG PHN MM PROII M PHNG MT

S S TRONG CNG NGHIP HA HC

I- Gii thiu tng quan

1- Mc ch, vai tr ca thit km phng

Thit k m phng l qu trnh thit k vi s tr gip ca my tnh vi ccphn mm chuyn nghip

M phng l mt cng c cho php ngi k s tin hnh cng vic mt cchhiu qu hn khi thit k mt qu trnh mi hoc phn tch, nghin cu cc yu

tnh hng dn mt qu trnh ang hot ng trong thc t.

Tc ca cng c m phng cho php kho st nhiu trng hp hn trongcng thi gian vi chnh xc cao hn nu so vi tnh ton bng tay. Hn na,

chng ta c th tng ha qu trnh tnh ton cc s cng ngh trnh

vic phi thc hin cc php tnh lp khng c cshoc m mm.

Thit k m phng thng c s dng :- Thit k (Designing) mt qu trnh mi- Th li, kim tra li (Retrofitting) cc qu trnh ang tn ti- Hiu chnh (Troubleshooting) cc qu trnh ang vn hnh- Ti u ha (Optimizing) cc qu trnh vn hnh

xy dng mt m hnh m phng hiu qu, chng ta phi xc nh ng mctiu. Bc u tin trong bt c mt qu trnh m phng no l lng ha cc

mc tiu cng nhiu cng tt. Cc kt qut c thng ph thuc vo cc


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yu cu t ra. Nh vy, trc khi m phng mt qu trnh nn t ra cc cu

hi sau :

-

Mc ch s dng cng c m phng trong trng hp ny lm g ?- Qu trnh m phng s thc hin nhng vic g ?- S phc tp c cn thit khng ?- Cn thit phi tm ra cc kt qu no t qu trnh m phng ?

Cn nhrng cc gi tr thu c t kt qu m phng ph thuc rt nhiu vonhng la chn ban u m chng ta nhp vo.

2- Cc phn mm m phng trong cng nghha hc

Trong cng ngh ha hc, ngi ta s dng rt nhiu cc phn mm m phng :- DESIGN II (WINSIM) : s dng trong cng nghip ha hc ni chung- PRO/II (SIMSCI) : s dng trong cng nghip ha hc, cng nghip lc -

ha du

- PROSIM : s dng trong cng nghip ha hc- HYSIM (HYSYS) : s dng trong cng nghip ch bin kh

Trong cc phn mm k trn, phn mm PRO/II l phn mm ni ting nht,c s dng rng ri nht trong nhiu lnh vc cng nghip.

II- Phn mm PRO/II

1- Lnh vc sdng

Phn mm PRO/II l phn mm tnh ton chuyn dng trong cc lnh vc cngngh ha hc ni chung, c bit trong lnh vc lc du, ha du, polymer, ha

dc, ... y l phn mm tnh ton rt chnh xc cc qu trnh chng ct. L

sn phm ca SIMSCI, hnh thnh t nm 1967 v c chnh thc s dng vo


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nm 1988 sau nhiu ln c ci tin. Hin nay, chng ta ang s dng phin

bn PRO/II 7.0

PRO/II vn hnh theo cc modul lin tip, mi thit bc tnh ring l v lnlt tnh cho tng thit b.

PRO/II bao gm cc ngun d liu phong ph : th vin cc cu t ha hc, ccphng php xc nh cc tnh cht nhit ng, cc k xo vn hnh cc thit b

hin i cung cp cho cc k s cng ngh cc k nng biu din tt c

cc tnh ton cn bng vt cht v nng lng cn thit khi m phng cc trng

thi dng ca cc s cng ngh. Phn mm PRO/II c s dng theo nhm 2 mc ch chnh:

- Thit k mt phn xng mi (Sizing)- M phng mt phn xng c xy dng trong thc t nghin cu

cc yu t nh hng n s vn hnh ca n (Rating) nh : thay i

ngun nguyn liu, iu kin vn hnh hoc tiu chun k thut ca sn

phm, ...

2- Qu trnh m phng bng phn mm PRO/II

Trc khi tin hnh m phng, chng ta phi din t cc d liu t s thct thnh m hnh m phng. Qu trnh ny bao gm cc bc sau :

- Xc nh hn vo : c 3 hn vo : h Anh, h Mt v h SI. Tutrng hp, chng ta chn hn vo cho thch hp, thng thng chnh Mt;

- Xc nh thnh phn cu t c trong h : c chn t ngun d liuphong ph cc cu t ca PROII;

- La chn cc phng trnh nhit ng thch hp : trn c s thnh phnha hc ca nguyn liu v iu kin vn hnh ca thit b ;


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- La chn cc dng nguyn liu v sn phm : xc nh thnh phn, trngthi nhit ca cc dng;

-

Xc nh cc d liu v thit b v iu kin vn hnh cho cc thit b. Hn na, trong nhiu trng hp chng ta phi thay i s cng ngh thc t

sang mc ch m phng. Mc d c s tng ng gia s cng ngh thc t

v s m phng nhng vn c nhng s khc bit cn ch .

V cng c m phng ch m t trng thi dng nn trong s m phngkhng nn b tr cc thit biu khin, kim tra.

PRO/II mc nh Condenserc xem l 1 bc thay i nng (1 a lthuyt) v Reboiler cng c xem l mt bc thay i nng v dng Kettle

c mc nh s dng.

III- L thuyt nhit ng hc

Cc tnh cht nhit ng l c sd liu quan trng nht cho vic tnh ton qu

trnh phn tch ton h thng.

C nhiu phng php tnh ton cc tnh cht ny, trong , quan trng nht l 2

phng php :

- Phng php tng quan : API v Rackett- Phng php phng trnh trng thi : phng trnh bc ba tng qut, cng

thc Alpha, cc qui lut hn h p, phng trnh SRK, phng trnh PR,

phng trnh SRKP, SRKM, SRKS, ...

Phng php API v Rackett tnh ton kh chnh xc t trng ca pha lng, cn

cc tnh cht nhit ng khc nh : enthalpie, entropie lng v hi, t trng pha hi,

... th c tnh ton rt chnh xc bng cc phng trnh trng thi nh : SRK,

SRKM, ...


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IV- Csla chn m hnh nhit ng

La chn m hnh nhit ng thch hp cho mt ng dng c thng mt vaitr rt quan trng, nh hng ln n chnh xc ca kt qu m phng

Mi phng php nhit ng cho php tnh cc thng s sau :- Hng s cn bng pha K : th hin s phn b cu t gia cc pha iu

kin cn bng

- Enthapie ca cc pha lng v pha hi : xc nh nng lng cn thit chuyn mt h t trng thi nhit ng ny sang trng thi khc

- Enthapie ca cc pha lng v pha hi : nhm phc v vic tnh ton ccmy nn, gin nv nng lng t do ti thiu cc thit b phn ng

- T trng ca pha lng v pha hi : tnh ton qu trnh truyn nhit, trlc v xc nh kch thc thp chng ct

la chn m hnh nhit ng thch hp, nn da vo cc yu t sau :- Bn cht ca cc c trng nhit ng ca h nh : Hng s cn bng

lng-hi (VLE : Vapor Liquid Equilibrium) ca cc qu trnh chng ct,

c c hoc bc hi, qu trnh trch ly, ...

- Thnh phn ca hn hp- Phm vi nhit v p sut- Tnh sn c ca cc thng s hot ng ca cc thit b

C th, ta c th da vo s sau :


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V- Cc phn cbn ca PROII

1- Giao din ca PROII- Quic ban u

Khi khi ng PROII, u tin s xut hin mt ca s giao din qui c ban u:

Cc nt hoc cc biu tng trong mt vi trng hp c vin quanh bi 1 trong

6 mu: , xanh lc, xanh dng, vng, nu v en. ngha ca mi mu nh sau :

: d liu yu cu cn phi nhp Xanh lc : d liu mc nh hoc la chn Xanh dng : d liu bn va cung cp tho mn yu cu Vng : bo rng s liu bn va nhp ngoi khong cho php Nu : d liu khng c gi tr en : d liu khng yu cu nhp vo


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2- Ca sPRO/II

TFile menu Chn New : mt ca sView1 s xut hin cho chng ta mt

flowsheetmi nh sau:

Mn hnh bao gm :

Dng trn cng gi l Application Title Bar (Thanh tiu ng dng), c tnca ng dng l PRO/II with PROVISION, km theo l Document Title Bar

(Thanh tiu ti liu) c tn ca chng trnh m phng ang thc hin (chng

hn l View 1 - l tn nguyn ca ti liu khi mi khi ng PRO/II)

Dng th hai gi l Menu Bar (Thanh trnh n) gm 10 mc t File n Help ; Dng th ba gi l Standard Tool Bar (Thanh cng c chun) cha biu tng ca

cc lnh thng dng

Bn phi v pha di mn hnh l thanh trt dc v thanh trt ngang Bn phi mn hnh, bn ngoi thanh trt dc l thanh cng cfloating PFD (Pipe

Flow Diagram). Nu thanh cng c PFD khng hin th th ta c th gi n nh sau :


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- click vo biu tng Show or Hide PFD Palette trn Standard Tool Bar- hoc tViewPalettes nhp chn (hoc khng) PFD

Ngoi ra cn c thanh cng cRun. lm xut hin hoc bin mt thanh cng cny cng tViewPalettes nhp chn (hoc khng) Run

VI- Cc thao tc thng dng trong m phng bng PRO/II

1- Mmt chng trnh m phng mi (Opening a New Simulation)

TFileMenuNew

Nu bn mun PRO/II lun lun c mvi mt chng trnh m phng mi Options MenuNew File on Startup

2- Mmt chng trnh m phng c (Opening an Existing Simulation)

Bn c th mbt k mt chng trnh m phng no c ghi trc chnh sa,

xem hoc in. Qui trnh :

TFileMenuOpen hin th ca sOpen Simulation . nh tn chng trnh vo hoc chn tn file m phng OK hocEnter hin th file Simulation cn thit3- Ghi mt file m phngang hin hnh (Saving the Current Simulation)

a- Ghi mt file m phngang hin hnh

TFileMenuSave nu bn cha ghi chng trnh m phng ny ln no th shin th ca sSave as nhp tn Chn OKhoc nhp Enter. Cn sau ln ghiu tin, mun ghi li file ang hin hnh nhp vo biu tng Save

Chng trnh PRO/II s t ng nn 3 file d liu (*.pr1, .pr2, .pr3) v 1 fileflowsheet biu cc dng (*.sfd) thnh mt file n *.prz. V vy, bn cnh vic

gim kch thc ca cc file lu tr cn m bo rng vic ci t file hon thnh

mi khi chng ta ghi cc chng trnh m phng


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Chc nng Autosave ca PRO/II s tng to mt file sao chp d phng (backupfile). Nu bn ng hoc thot ra chng trnh m phng m khng ghi th file ny s

b xa. Hy chn Options / simulation Defaults / Autosave t menu bar hin th

ca sAutosave Options nhp chn Automatic Save File every nhp chu k

save (pht) OK

b- Ghi mt file m phng vi mt tn khc

TFileMenu chn Save as hin th ca sSave as Nhp tn mi cho chng

trnh m phng Chn OKhoc nhpEnter

4- Xa mt chng trnh m phng (Deleting a Simulation) TFileMenu chn DeletePRO/II s hin th mt danh sch cc file m phng

c

Nh p hoc chn tn ca flie mun xa (Bn khng th xa mt chng trnh mphng ang hin hnh)

Chn OKhoc nhpEnterPRO/II s xa tt c cc file lin kt vi chng trnhm phng ny

5- Sao chp mt chng trnh m phng (Copy a Simulation)

PRO/II c th copy tt c cc file lin kt vi chng trnh m phng (3 file d liuv 1 flowsheet) vo mt file m phng mi hoc ang hin hnh. Nu bn mun

copy vo mt file m phng ang hin hnh PRO/II s hi bn c mun vit ln

file hin hnh ny khng ?

TFileMenu chn Copy PRO/II s hin th ca sSelect File to CopyHy chn tn file cn copy (Bn khng th copy mt chng trnh m phng ang

hin hnh) Nhp tn file ch (target) OK


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6- Thay i dngng vin cc dng (Modifying the Flowsheet Stream Border

Style)

Thng thng ng vin cc dng thng c dng hnh ch nht Chng ta c ththay i thnh ng vin dng trn. Qui trnh nh sau :

- Right-click vo dng c chn hin th ca s la chn- Chn Display xut hin ca sStream Style- Chn Circle t drop-down list box ca Stream Label Border- click OKng vin dng c chn t dng hnh ch nht chuyn thnh

ng vin dng trn

Vi cch nh trn, bn c th thay i dng ng vin cho tng dng ring l. Cnnu mun, bn c th click chut tri v qut chn mt hnh ch nht bao xung quanh

cc dng mun thay i dng ng vin ri tin hnh qui trnh nh trn. Hoc bn c

th mc nh dng ng vin cho tt c cc dng ngay tu theo qui trnh sau :

- TOptionsMenuDrawing DefautsStream Display hin th ca sStream Style

- Chn Circle t drop-down list box ca Stream Label Border. V la chn nych c gi tr khi chng ta chn Namemc Stream Label Type OK

7- Hin thtnh cht ca dng trn s m phng

Qui trnh nh sau :- Right-click vo dng c chn hin th ca s la chn- Chn Display xut hin ca sStream Style- Chn Properties t drop-down list box mc Stream Label Type- Mc nh mc Property List l Property Label List s hin th tn, nhit

, p sut v lu lng dng OK


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8- Sdng Flash Hot-Key Tool

PRO/II c mt cng c hu ch cho php hin th nhanh chng cc tnh ton flash cabt k dng no c chn l cng cFlash Hot-Key, cung cp mt phng

tin nhanh chng, d dng xc nh hm lng v thnh phn ca pha lng v pha

hi ca bt k dng no


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9- Xut mt s m phng ra ca s lu tr tm (Exporting the PFD to the

Windows Clipboard)

TClipboard, bn c th dn mt cch n gin hnh v ln bt k mt chng trnhson tho no nh trong Microsoft Word. Qui trnh nh sau :

TMenuFileExport Chn Flowsheet Drawing Click OKPRO/II s hin th mt hp hi thoi khng nh rng flowsheet

c xut ra ca s lu tr tm

10- Nhp mt file PRO/II c sn (Importing a PRO/II Keyword Input File)

Bn c th nhp mt file keyword Input ca PRO/II dng *.inp c sn vo giao din

PRO/IIang hin hnh. PRO/II s tng chuyn i file ny thnh mt s tnh ton

v chng ta c th tin hnh m phng nh m phng trn mt s PFD, t chng ta

c th chnh sa theo mnh

TMenuFileImport Nhp hoc chn tn ca flie mun nhp Chn OKhoc nhpEnter11- Xc nh cc tnh cht vcn bng lng - hi ca cc h2 cu t(Display

BVLE)

xc nh cc tnh cht v bng lng - hi ca cc h 2 cu t ny p sut thng (1

atm) hay mt p sut bt k no , ta s dng cng cDisplay BVLE.

Qui trnh nh sau :

Chn hn v Chn cu t Chn m hnh nhit ng thch hp


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Nhp chn biu tngDisplay BVLE Chn cc cu t, chn p sut v nhp chnCalculate Ta sc 5 loi biu :

Biu X - Y Biu T - X - Y Biu h s Fugacity Biu hng s cn bng K thay i theo thnh phn mol Biu hng s cn bng K thay i theo


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VII- BI TP P DNG

Bi ton 1: M phng s cng nghca phn xng tch Mthane

Thp Demethanizer tch methane ra khi hn h p kh trong s s dng turbo-

expander.

Lu lng dng kh nguyn liu : 8 m3/s

Nhit : 120 oF

Ap sut : 602,7 psia (pound per square inch absolute)

(1 psi = 0,06896 bar; 602,7 psia = 588,2 psig; 1pound = 453,6 g)Thnh phn ca hn hp kh ban u nh sau :

Cu t % mol Cu t % mol

N2

CH4

C2H6

C3H8

i-C4H10

7,91

73,05

7,68

5,69

0,99

n-C4H10

i-C5H12

n-C5H12

C6H14

C7H16

2,44

0,69

0,82

0,42

0,31

Trong : Hiu sut ca my nn l 75%; Hiu sut ca thit b gin n: 80%

Yu cu cht lng ca sn phm y l t l C1/C2 = 0.015

Hy xc nh:

1.

Cng sut thc ca my nn C1?2. Thnh phn, nhit v p sut ca cc dng sn phm kh v lng?

Phng php tin hnh: Chng ta s chia s trn thnh 2 vng :

Vng 1 : m phng 3 thit bn gin lm quen vi phn mm PROII Vng 2 : Chng ta s m phng ton b qu trnh tm hiu nhng im u vit

ca phn mm PROII


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Nguyn l ha cng nghi p Nguyn l ha cng nghi p


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Bi ton 2: M phng thit btch kh - lng

Cho vo thit b tch kh lng mt dng nguyn liu vi cc d liu sau:

Lu lng : 100 kmol/h; t = 300C ; P = 10 bar Thnh phn ha hc: Mthane : 13 kmol/h

Ethane : 22 kmol/h

Propane : 38 kmol/h

Butane : 22 kmol/h

Pentane : 5 kmol/hiu kin lm vic ca thit b tch: 300C v 7 bar

Hy xc nh:

1. Phn mol bay hi ca nguyn liu trong iu kin ca bnh tch?2. Thnh phn ca lng v hi ra khi thit b tch?3. Nng sut nhit ca thit b tch?


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Bi ton 3: Tnh nhit si ca mt hn hp hai pha mt p sut

nhtnh

Nguyn liu c thnh phn nh bi ton 2, lu lng = 5500 kg/h.

Hy xc nh:

1. Nhit si ca hn hp nguyn liu ny p sut 7 bar?2. Hng s cn bng pha ca cc cu t ?3. Thnh phn hn hp hi cn bng vi lng?4. Nng sut nhit ca thit b tch?

Gii quyt bi ton

gii quyt bi ton trn, ta tin hnh cc bc:

Gi thit cho hn hp nguyn liu ny i vo mt bnh tch lm vic p sut l 7bar.

Tin hnh m phng nh bi ton 2 V mun xc nh nhit si ca hn hp ca sFlash Drum, mcSecond

Specification ChnBubble pointmc Unit Specification

Do phi xc nh hng s cn bng pha ca cc cu tca sFlash Drum, mcPrint Option Chn Include Component K - values


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S bi ton

Bi ton 4: M phng thp tch propane

Tnh cho thp Depropanizer vi cc d liu ban u nh sau :

Nguyn liu :- nng sut : 400 tn/ngy- P = 18 bar- c thnh phn 40% hi gm : 26% khi lng C3 v 74 % khi lng C4

Thp :- 22 a l thuyt; np liu a 13- p sut nh : 16,5 bar; trlc : 10 mbar/a l thuyt- thit b ngng t hon ton ; p sut bnh tch : 16,2 bar

Ch tiu cht lng sau :- sn phm nh : c 0,5% khi lng C4


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- sn phm y : c 0,5% khi lng C3 Hy xc nh :

- Ch s hi lu ?- Nng sut nhit ca thit bun si li v thit b ngng t (MkCal/ngy)- Lu lng sn phm nh v sn phm y ?

S bi ton


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Bi ton 5: Xc nh a np liu tiu cho thp tch propane bng

cng c Optimiser


Nguyn liu :- nng sut : 400 tn/ngy- P = 18 bar- c thnh phn 40% hi gm : 26% khi lng propane v 74 % khi lng

butane

Thp :- 22 a l thuyt- p sut nh : 16,5 bar; trlc : 10 mbar/a l thuyt


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- thit b ngng t hon ton- p sut bnh tch : 16,2 bar

Ch tiu cht lng sau :- sn phm nh : c 0,5% khi lng C4- sn phm y : c 0,5% khi lng C3

Hy xc nh a np liu ti u nng sut ca thit bun si li l b nht


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Bi ton 6: Xc nh sa l thuyt ti thiu v ch shi lu ti

thiu cho thp tch propane bng phng php shortcut

Bi ton


Nguyn liu :- nng sut : 400 tn/ngy- P = 18 bar- c thnh phn 40% hi gm : 26% khi lng propane v 74 % khi lng

butane

Thp :- p sut nh : 16,5 bar- trlc : 10 mbar/a l thuyt


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CHNG 3: TRCH LY

3.1. Nguyn tc

- Trch ly l qu trnh tch hon ton hay mt phn cht ha tan trong cht lng hay chtrn bng mt cht lng khc Ch xt cho hn hp lng - lng

- Yu cu ca dung mi:- Ha tan chn lc cu t cn tch;- H s khuych tn D ln vn tc chuyn khi ln;- Nhit dung ring v nhit ha hi nh (tit kim khi hon nguyn dung mi);- bay hi ln (nhit si nh);- Khng n mn thit b, khng tc dng ha hc vi cc cu t trong hn hp;- R tin, d kim;

3.2. S

Hn hp lng A + B(A: cu tcn tch)

S: dung mi

Pha R (B + A-S)

Pha E (A-S + B)

3.3. ng dng

- Trong cng nghip lc ha du: tch cc sn phm c nhit si gn nhau;- Trong cng nghip dc phm: tch pnicilline t hn hp ln men;- Trong cng nghip luyn kim: tch kim loi trong dung dch ;- Trong cng nghip thc phm: tch du bo, tinh du t nguyn liu;


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CHNG 4: THIT B PHN NG

4.1. I CNG

4.1.1. PHN LOI THIT B PHN NG

a- Theo pha ca h

Theo bn cht pha : thit b phn ng pha kh, lng hoc rn ; Theo s pha :

- thit b phn ng mt pha (ng th) : pha kh hoc lng,- thit b phn ng nhiu pha (d th) :

- thit b phn ng hai pha : kh-lng, lng-lng, kh-rn, lng-rn- thit b phn ng ba pha : kh-lng-rn.

Theo trng thi pha : thit b phn ng pha lin tc hoc pha phn tnb- iu kin tin hnh qu trnh

Theo phng thc lm vic:- thit b phn ng gin on- lin tc- bn lin tc

Theo iu kin nhit- thit b phn ng ng nhit- on nhit

c- Theo iu kin thy ng

Theo chiu chuyn ng ca cc pha :- thit b phn ng xui dng, ngc dng hoc dng cho nhau- thit b phn ng dc trc hoc xuyn tm


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Theo ch chuyn ng :- thit b phn ng dng ng ;- thit b phn ng khuy trn hon ton- thit b phn ng nhiu ngn.

Theo trng thi tng xc tc :- thit b phn ng tng xc tc cnh ;- thit b phn ng tng xc tc di ng ;- thit b phn ng tng si ;- thit b phn ng tng xc tc ko theo

4.1.2. PHN LOI CC THIT B PHN NG THEO PHNG THC LM

VIC

Tu thuc vo phng thc lm vic, ngi ta chia thit b phn ng thnh 3 loi :

a- Thit b phn ng gin on :

nh ngha : l thit b phn ng lm vic theo tng m, ngha l cc thnh phn thamgia phn ng v cc cht ph gia (dung mi, cht tr) hoc cc cht xc tc c a

tt c vo thit b ngay t thi im u. Sau thi gian nht nh, khi phn ng t

c chuyn ha yu cu, ngi ta cho dng thit b v tho sn phm ra.

u im :- Tnh linh ng cao : c th dng thit b thc hin cc phn ng khc nhau

to ra cc sn phm khc nhau- t chuyn ha cao do c th khng ch thi gian phn ng theo yu cu- Chi ph u t thp do t phi trang b cc thit biu khin tng

Nhc im :- Nng sut thp do thi gian mt chu k lm vic di : i hi thi gian np liu,

t nng, lm ngui, tho sn phm v lm sch thit b


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- Mc cgii ha v tng ha thp- Kh iu chnh v khng ch qu trnh do tnh bt n nh ca phng thc lm

vic gin on

- Mc gy c hi hoc nguy him i vi ngi sn xut cao hn do mc tng ha thp, ngi cng nhn phi tip xc nhiu hn vi cc ha cht

Phm vi ng dng :- Ch thch hp vi cc phn xng nng sut nh- Phc v cho mc ch sn xut nhiu loi sn phm khc nhau trong cng mt

thit b

b- Thit b phn ng lin tc :

nh ngha : l thit b m trong cc cht tham gia phn ng c a lin tc vothit b v sn phm cng c ly ra lin tc. Sau thi gian khi ng th nhit , p

sut, lu lng v nng cc cht tham gia phn ng khng thay i theo thi gian,

thit b lm vic trng thi n nh

u im :- C kh nng cgii ha v tng ha cao- nng sut cao do khng tn thi gian np liu v tho sn phm- cht lng sn phm n nh do tnh n nh ca qu trnh

Nhc im :- Chi ph u t cao, trc ht l do i hi phi trang b cc thit b tng iu

khin m bo tnh n nh ca qu trnh

- Tnh linh ng thp, t c kh nng thc hin cc phn ng khc nhau, to ccsn phm khc nhau

Phm vi ng dng : thit b phn ng lin tc c s dng thch hp cho cc qutrnh sn xut vi nng sut ln, cht lng sn phm m bo


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c- Thit b phn ng bn lin tc :

nh ngha : l thit b m trong c thnh phn cht tham gia phn ng a vogin on cn cc cht khc a vo lin tc. Sn phm c th ly ra gin on hay

lin tc

Phm vi ng dng : c thc hin i vi nhng qu trnh khng c kh nng thchin theo phng thc lin tc, cn nu thc hin theo phng thc gin on li cho

nng sut thp

Khi tnh ton thit k thit b phn ng phi da trn yu cu ca sn xut (nngsut v cht lng sn phm). Trn cscc phng trnh cn bng vt cht v cn

bng nhit - l nhng phng trnh ton hc m t quan h gia cc thng sng hc,

nhit ng v cc iu kin thc hin qu trnh vi cc thng sc trng cho kch

thc hnh hc ca thit b nh th tch, chiu di thit b, thi gian lu, ... t c th

tnh ton cc kch thc cbn ca thit b.

4.1.3. NHIM V THIT K THIT B PHN NG

Thit k mt thit b phn ng l xc nh kch thc ca thit b t c hiusut thu sn phm mong mun, ng thi xc nh nhit , p sut v thnh phn ca

hn hp phn ng iu kin vn hnh ti cc phn khc nhau ca thit b.

Cc s liu cn thit hay cn gi l iu kin thit k bao gm :- Cc d liu ban u ca dng nguyn liu nh : lu lng, nhit , p sut,

thnh phn cc cht tham gia phn ng, ...

- Ch vn hnh ca thit b : gin on hoc lin tc, on nhit hoc ngnhit, ...

- Yu cu v nng sut v cht lng sn phm. Thit k ti u da trn nguyn liu, chi ph ban u, chi ph vn hnh v gi tr

thng mi ca sn phm cui cng


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4.2. CN BNG VT CHT V CN BNG NHIT TNG QUT

4.2.4. Cn bng vt cht

Cn bng vt cht cho mt tc cht c vit di dng tng qut c th p dng chobt k mt dng thit b phn ng no.

Trong mt phn t th tch V v mt phn t thi gian t, cn bng vt cht dngtng qut l :

Lng tc cht

nhp vo phn

t th tch

Lng tc cht

ri khi phn

t th tch

Lng tc cht

phn ng trong =

phn t th tch

Lng tc cht

cn li trong (III-1)

phn t th tch

S hng th ba ph thuc vo vn tc phn ng trong phn t th tch V v c dng(-rA).V.t vi (-rA) - phng trnh vn tc phn ng ha hc

phng trnh (5-1) c th tnh theo khi lng hoc theo mol.4.2.5. Cn bng nhit

Cn bng nhit nhm mc ch xc nh nhit ti mi im trong thit b phn ng(hay ti mi thi im nu thit b hot ng gin on) xc nh ng vn tc ti

im .

Trong mt phn t th tch V v mt phn t thi gian t, phng trnh cn bngnhit tng qut cho thit b phn ng l :

Nhit do tc cht

mang vo phn

t th tch

Nhit do tc cht

mang ra khi +

phn t th tch

Nhit trao i

vi mi trng =

bn ngoi

Nhit tch t

li trong phn (III-2)

t th tch

Dng ca phng trnh (III-1) v (III-2) ph thuc vo loi thit b phn ng vphng php vn hnh. Trong nhiu trng hp, mt hoc nhiu s hng ca phng

trnh trn s khng c.


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4.3. M TMT S DNG THIT BPHNNGNG THCBN

Thit b phn ng lin tc

i vi dng thit b ny, ta phn thnh 2 loi cbn :

a- Thit b phn ng dng ng :

Trong thit b phn ng dng ng, nguyn liu c nhp vo mt u ca ng hnhtr v dng sn phm ra u kia ;

Do thit b ny thng hot ng trng thi n nh, khng c s khuy trn theophng dc trc nn tnh cht ca dng chy thay i tim ny n im khc ch

do qu trnh phn ng. V vy, ngi ta gi thit rng trong thit b dng ny, tnh cht

ca cc phn t trn cng mt tit din l nh nhau v khng thay i theo thi gian ;

Chng ta c sn gin ca thit b phn ng dng ng nh hnh v bn di. T c th biu din s ph thuc ca nng tc cht c xt vo chiu di ca thit

b phn ng l mt ng cong lin tc v gim dn tu vo n u ra ca thit b.

Sn gin ca thit b phn ng dng ng

u vo u ra Chiu di thit b

Sn phmTc cht

xAf

xAo

Thit b phn ng dng ny thng s dng 1 trong 3 loi tng xc tc sau : tng xctc cnh, di ng v ko theo.


53/72


V phng din ng hc, c th m t thit b phn ng dng ng theo s sau :CAo

FAoxAo= 0vo

CAf

FAfxAfvf

FAxA FA+dFAxA+ dxA

V

dx

dVxA

Phng trnh (III-1) v (III-2) c thc vit cho mt n nguyn th tch V :

Lng tc cht

nhp vo phn

t th tch

Lng tc cht

ri khi phn

t th tch

Lng tc cht

phn ng trong =

phn t th tch

Lng tc cht

cn li trong (III-1)

phn t th tch

i vi phng trnh (III-1) :- S hng th nht l FAo.(1 - xA ).t ;- Nu chuyn ha khi ra khi phn t th tch l xA + xA th s hng th hai

l : FAo.(1 - xA - xA).t ;

- S hng th ba l (- rA ). V. t ;- S hng th t bng 0 v qu trnh trng thi n nh.

Vy phng trnh (5-1) c vit l :

FAo.(1 - xA ).t FAo.(1 - xA - xA).t (- rA ). V. t = 0

Hay : FAo. xA (- rA ). V = 0


54/72


Chia 2 v cho V v ly gii hn khi cho V 0, ta c :

( )

0A

AA

F

r

dV

dx =

V FAo l lu lng ban u ca tc cht nn khng i, ly tch phn theo xA t xA1n

xA2 ta c :

( )( )1-VI =

2A

1A0

x

x A

A

A r

dx

F

V

V d 1 : Phn ng phn hy pha kh ng th650 oC :

4PH3 (k) P4 (k) + 6H2 (k)

y la phn ng bc mt vi phng trnh vn tc l : ( rPH3 ) = (10 h-1 ) CPH3

Tm th tch bnh phn ng dng ng hot ng 650 oC v 4,6 at t chuyn ha

l 80% vi lu lng dng nguyn liu phosphin tinh cht ban u l 2 kmol/h.

Gii :

t A = PH3, R = P

4, S = H

2, lc phn ng c vit di dng :

4A R + 6S

Th tch bnh phn ng dng ng c xc nh theo cng thc :

( ) ===

=

80

0 A

AA

80x

0x A

AA Ck

dxF

r

dxFV

0

2A

1A

0

,,

p sut khng i, ta c :

( )

( ) AA

A

A0

AAAA x1

x1C

x1V

x1F

V

FC

0

0

+

=+

==

Ly tch phn, ta c :

( )

+=

+

=

+

=A

0

0

A

0

0

0

0

x

0A

AA

A

A

A

Ax

0 A

A

A

AA

AA xx1

11

Ck

Fdx

x1

x1

Ck

F

x1

x1Ck

dxFV ln


55/72


Vi cc s liu cho trc :

FAo = 2 kmol/h = 2000 mol/h

k = 10 h-1

xA = 0,8

R = 0,082 at.l/mol.K

( )

7504

47

0602736500820

64CAo

,

,,

,

=

=

=+

=

Vy :( )

lt

,,,

ln,,

7388V

80750801

17501

06010

2000V

=

+

=

b- Thit b phn ng dng khuy trn l tng

C 3 cch vn hnh : lin tc (n nh) , gin on v bn lin tc.

a- Lin tc b- Gin on c- Bn lin tc

c c trng bng qu trnh khuy trn l hon ton, do hn hp phn ng ngnht v nhit v thnh phn trong tt c cc phn ca thit b v ging dng ra ca

sn phm. iu ny c ngha l phn t th tch V trong cc phng trnh cn bng

c thc ly l th tch V ca ton thit b.


56/72


Ngi ta gi thit rng u vo ca thit b phn ng, nng ca tc cht gim mtcch t ngt v ng bng nng ca mi im trong ton th tch ca thit b v

nng ca dng sn phm ra. Ta c th biu din s thay i nng ca tc cht

tu vo n u ra ca thit b l mt ng gp khc nh sau :

Nng ca tc cht

u vo u ra Th tch thit b

CAo

CAf

Thit bphn ng khuy trn hotngn nh :

Xt trng hp n gin ch c mt dng nhp liu v mt dng sn phm v tnhcht ca cc dng ny khng thay i theo thi gian, nh vy :

- Hai s hng u trong phng trnh cn bng l khng i : Lng tc cht nhpvo th tch V ca thit b phn ng l FAo(1-xAo).t v lng tc cht ra khi

thit b phn ng l FAo (1-xAf).t ;

- V hn hp phn ng trong bnh c nhit v thnh phn ng nht, nn vntc phn ng l khng i v c xc nh vi nhit v thnh phn ca dng

sn phm v bng (-rA ).V.t ;

- V thit b phn ng hot ng lin tc v n nh nn khng c s tch t tccht trong thit b, v vy s hng th t bng 0 ;

Vy phng trnh vt cht vit cho thit b phn ng khuy trn hot ng n nhtrong khong thi gian t l :

FAo(1-xAo).t FAo (1-xAf).t (-rA ).V.t = 0


57/72


Hay :( )

( )2-IVfA

AoAf

AA r

xx

C

V

F

V

00

=

=

trong : xAo

v xAf

- chuyn ha ca tc cht trc khi vo thit b v sau khi ra

khi thit b ;

v - lu lng ca dng nguyn liu (l/h)

Nu dng nguyn liu cha cu t A hon ton cha chuyn ha, ngha l xAo = 0 th :

( )( )3-IV

fA

Af

A r

x

F

V

0

=

V d 1 : Xt phn ng pha lng, thun nghch : A + B R + S

vi k1 = 7 lt/mol.ph v k1 = 3 lt/mol.ph c thc hin trong bnh phn ng dng khuy

trn hot ng n nh c th tch 120 lt.

Hai dng nguyn liu : mt dng cha 2,8mol A/l, mt dng cha 1,6mol B/l c

a vo bnh phn ng vi lu lng th tch bng nhau t chuyn ha ca B gii

hn l 75%. Xc nh lu lng ca mi dng.

2,8 mol A/l

xB = 75%

1,6 mol B/l


58/72


Gii :

Nng ca cc cu t trong dng nguyn liu ban u l :

CAo = 1,4 mol/l

CBo = 0,8 mol/l

CRo = CSo = 0

Vi chuyn ha ca B l xB = 75%, thnh phn ca hn hp phn ng trong bnh hoc

trong dng sn phm ra l :

CA = CAo CBo.xB = 1,4 0,8 0,75 = 0,8 mol/l

CB = CBo CBo.xB = 0,8 0,8 0,75 = 0,2 mol/l

CR= CS = CBo.xB = 0,8 0,75 = 0,6 mol/l

Lu : CA = CAo CAo.xA = CAo CBo.xB

Vy : CAo.xA= CBo.xB

Phng trnh vn tc ca phn ng thun nghch ny l :

(rA) = (rB) = k1CACB k2CRCS

= 7 (l/mol.ph) 0,8(mol/l) 0,2 (mol/l) 3(l/mol.ph) 0,6(mol/l) 0,6 (mol/l)

= 0,04 mol/l.ph

Theo biu thc (IV-2 ), ta c :

( ) ( )( ) ( ) ( )

( )( )phl8

750lmol80

phlmol040l120

xC

rVv

r

xC

r

xC

v

V

BB

fB

fB

BB

fA

AA

0

00 /,./,

./,=

=

=

=

=

Vy, lu lng mi dng l 4 lt/ph.


59/72


c- Thit b phn ng nhiu ngn (tag)

c im :- vn hnh lin tc ;- gm nhiu ngn, mi ngn c lp cnh khuy khuy trn lin tc v hn hp

phn ng s chuyn ng t ngn u n ngn cui nhchy trn. V vy c

th xem y l h nhiu bnh phn ng khuy trn lin tc mc ni tip v nng

ca tc cht trong mi ngn l nh nhau v gim dn t ngn u n ngn

cui. Hay ni mt cch khc chuyn ha ca tc cht trong mi ngn l nh

nhau nhng tng dn t ngn u n ngn cui.

Nu s ngn tng n v cc th th tch vi ca mi ngn s gim n ti thiu sao chotng th tch l khng i. Lc , s bin thin nng ca tc cht gia hai ngn

lin tip nhau l rt b v ta c th v mt ng lin tc thay cho ng gp khc

biu din s bin thin nng ca tc cht t ngn u n ngn cui. Do , dng

thit b phn ng ny c xem l dng trung gian gia thit b phn ng dng ng v

dng khuy trn lin tc.

CAo

CAf

CAf

CAo

N n 1 N n 2 N n 3 N n 4


60/72


4.4. P DNG PHNG TRNH THIT K

thc hin mt phn ng theo nhng iu kin cho trc, chng ta c th dngnhiu loi thit b phn ng khc nhau nh : thit b phn ng dng ng, thit b phnng khuy trn hot ng lin tc hoc gin on hoc h nhiu thit b phn ng mc

ni tip hoc song song.

Hai thng s thit knh hng n tnh kinh t ca qu trnh l th tch ca thit bphn ng v hiu sut thu cc sn phm. Vi mt thit b phn ng c kt cu v th

tch thch hp s cho hiu sut thu sn phm chnh cc i, ng thi hn ch lng

sn phm ph l cc tiu.

Trong chng ny, ta s so snh cc phng n thit k thit b phn ng khc nhaucho thit bn hoc cho h nhiu thit b phn ng.

4.4.6. SO SNH CC THIT B PHN NG N

4.4.6.1 Thit bphn ng khuy trn hotngn nh v thit bphn ngdngng vi phn ng bc mt v bc hai

Dng phng trnh vn tc tng qut :( ) nA

AA kCdt

dN

Vr ==

1

vi n bin i bt k t 0 3

Vi hai dng thit b phn ng ny, chuyn ha l hm ca lu lng nguyn liu,thnh phn nguyn liu, bc phn ng v h s bin i th tch.

Ta tnh thi gian lu i vi thit b phn ng khuy trn hot ng n nh :

( )( )

( )nA

nAA

nAoA

AAo

Ao

Aokh

x

xx

Ckr

xC

F

VC

v

V

+=

===

1

111

.

.

..

i vi thit b phn ng dng ng :

( )( )

( )nA

An

Ax

nAo

x

A

AAo

Ao

Ao

x

dxx

Ckr

dxC

F

VC

v

V AA

+=

=== 1

11

01

0

.

.


61/72


Chia hai phng trnh, v theo v ta c :

( )( )

( )( )

( )( )

( )1-V

.

.

.

.

.

+

+

=

=

Ax

0An

A

n

A

khA

n

AA

Ao

nAo

khAo

nAo

1nAo

kh

1n

Ao

dxx1

x1

x1

x1x

F

VC

F

VC

C

C

Nu khi lng ring khng i, th tch s khng i v = 0, ta c :

( )( )

( )

( )

.

.

=

Ax

0An

A

kh

n

A

A

1nAo

kh1n

Ao

dxx1

1

x1

x

C

C

( )( )

( )

( )[ ]( )2-V

.

.:1nvi,tch phnLy

1n

A

kh

n

A

A

1nAo

kh1n

Ao

x1n1

1

x1

x

C

C

=

( )( ) ( ) ln..:1nvi

A

khA

A

1nAo

kh

1n

Ao

x1x1

x

CC

==

Phng trnh (V-1) v (V-2) c biu din bng th trn hnh (4-1). Vi cng

nng nguyn liu ban u CAo v lu lng nguyn liu FAo, tung ca gin s

cho ta trc tip t s th tch ca hai dng thit b phn ng trn.

Hnh 4.1:

So snh hot ng ca TBPU khuy trn hot ng n nh v TBPU dng ng cho phn

ng bc n. Vi cng iu kin np liu, trc tung cho gi tr t s Vkh/V


62/72


4.4.6.2nh hng ca sbin i tlnng ban u ca tc cht trongphn ng bc hai

Vi phn ng bc hai loi : A + B sn phm , phng trnh vn tc l :

( ) ( ) BABA CCkrr ..==

Hnh (4-1) cho php ta so snh th tch ca hai loi thit b khi nng ban u

ca hai tc cht bng nhau. Tuy nhin trong thc t, nng ban u ca hai tc cht

thng khng bng nhau. T l ti u ph thuc vo cc yu t nh : chi ph phn tch

sn phm ra khi tc cht cha phn ng, chi ph hi lu tc cht, ...


63/72


Vi M = CBo / CAo > 1 v = 0 , thi gian lu ca tc cht trong thit b phn ng

dng ng l :

( ) ( )

A

A

AoAo

AoM

A

A

AoAo

AoM

x

x

kCF

VC

xM xMMkCF VC

=

=

=

=

=

1

1

111

1

1

.

ln..

Hnh (4-2 ) cho ta so snh s hot ng ca thit b phn ng dng ng vi cc gi

tr khc nhau ca CAo, FAo, M v xA vi = 0.

( )( )

1MAo

1MAo

C

C

=

Vi thit b phn ng dng khuy trn, hot ng n nh :


64/72


( )( )

( )21

1

1

1

Ao

A

Ao

AoM

AAAo

A

Ao

AoM

xkC

x

F

VC

xMxkC

x

F

VC

=

=

=

=

=

.

.

.

Hnh (4-3 ) cho ta so snh s hot ng ca thit b phn ng dng khuy trn, hot

ng n nh vi cc gi tr khc nhau ca CAo, FAo, M v xA vi = 0. Vi cng iu

kin FAo v CAo, tung ca hai hnh (4-2) v (4-3) cho ta t s ca hai loi thit b.

V d : Phn ng pha lng : A + B sn phm vi phng trnh vn tc l :

(-rA ) = (500 l/mol.ph ) CA.CB


65/72


c thc hin trong thit b phn ng dng ng vn hnh trong cc iu kin sau :

- th tch thit b : V = 0,1 l ;- lu lng th tch ca nguyn liu : v = 0,05 l/ph ;- nng ca tc cht trong nguyn liu : CBo = CAo = 0,01 mol/l

Hy :

a- Xc nh chuyn ha ca tc cht ?b- Vi cng vn tc v chuyn ha, tm th tch ca thit b dng khuy trn, hot

ng n nh ?

c- Vi cng vn tc, tnh chuyn ha c tht c trong thit b b dng khuy trnc cng th tch vi thit b dng ng ?

Khi thay i dng t l nng ban u ca tc cht trong nguyn liu : CBo =

0,015 mol/l v CAo = 0,010 mol/l, hy tnh :

d- Vi cng lu lng nguyn liu np vo, tm chuyn ha ca A trong thit b dngng ban u ?

e- Vi cng chuyn ha ban u, tm t l tng nng sut ng vi dng nguyn liumi ?

f- Tm lu lng nguyn liu cn thit np vo cho thit b phn ng dng khuy trn,hot ng n nh c V = 100 l, chuyn ha ca tc cht gii hn l 99% ?

Gii :

a-Xc nh chuyn ha ca tc cht trong thit b phn ng dngng :Tnh thi gian lu :

( )( )

( )phphl

l

v

V2

050

10===

/,

,

Do : k.CAo. = 500 (l/mol.ph). 0,01 (mol/l). 2 (ph) = 10


66/72


T hnh (4-2), giao im ca ng k.CAo. = 10 v ng M = 1 (nm ngang) cho ta gi

tr ca 1- xA = 0,09 hay xA = xB = 0,91 = 91%

b- Thtch ca thit b dng khuy trn, hotngn nh cngiu kin :Vi cng vn tc v chuyn ha, tung trn hnh (4-1) cho ta t s th tch ca hai

dng bnh phn ng Vkh / V. Vi xA = 0,91, ta tra c :

( )lVV

V

V

kh

kh

11101111

11

,,

===

=

c- chuyn ha ca tc cht trong thit b khuy trn hotngn nh c cng thtch :

Vi cng th tch bnh th k.CAo. = 10.

Giao im ca ng k.CAo. = 10 v ng M = 1 (nm ngang) trn hnh (4-3) cho ta

gi tr ca 1- xA = 0,28 hay xA = 0,72 = 72%

d- chuyn ha ca tc cht trong thit b dngng c M1 :M = CBo / CAo = 0,015/0,010 = 1,5.Vi cng lu lng nguyn liu np vo, gi tr ca k.CAo. s khng i v bng 10

(FAo = CAo.V). Trn hnh (4-2), t giao im ca hai ng k.CAo. = 10 v M = 1,5, ta

ngoi suy gi tr ca 1- xA = 0,006 hay xA = 0,994 = 99,4%

e- Tl tng nng sut vi dng nguyn liu mi :Dng nguyn liu mi c M = 1,5 v xA = 0,91. Tung trn hnh (4-3) cho ta t s :

( )

( )300

1

51

1

51 ,.

. ,, =

=

=

=

=

=

MAo

MAo

MAo

MAo

Cv

V

CvV

C

C

M CAo v V l ging nhau trong c hai trng hp, do lu lng th tch dng nguyn

liu mi s bng :


67/72


( )phlvv MM /,,,

,,170

300

050

300

1151 === ==

Nh vy, nng sut tng thm 240%.

f- Nng sut ca thit b khuy trn hotngn nh c V = 100 lt v xA = 99% :Vi xA = 99% = 0,99 1 - xA = 0,01 v M = 1,5 ; trn biu (4-3) ta suy ra :

( ) ( ) ( )phl

llmolphmollVkCv

v

VkCkC AoAoAo /,

/,./632

190

100010500

190190 =

====

4.4.7. H NHIU THIT B PHN NG

4.4.7.1 Thit b phn ng dng ng mc ni tip v / hoc mc song songa- Mc ni tip

Xt j thit b phn ng dng ng mc ni tip v gi x1, x2, ...,xj l chuyn ha

ca tc cht A khi ri khi thit b phn ng 1, 2, ..., j.

T cn bng vt cht da trn lu lng mol ca A vo thit b phn ng u tin,

ta vit c cho thit b phn ng th i :

( )

=

iA

iA

x

x A

A

Ao

i

rdx

FV

1

Vi j thit b mc ni tip :

( ) ( ) ( )

( )

=

++

+

=

+++==

=

=

Aj

a

Aj

A

A

A

Ao

x

A

A

x

x A

Ax

x A

Ax

x A

A

Ao

jj

i Ao

i

Ao

r

dx

r

dx

r

dx

r

dx

F

VVV

F

V

F

V

0

21

1

1

2

1

1

0

....

...

Nh vy, vi j thit b phn ng dng ng mc ni tip c tng th tch l V s cho

chuyn ha ng bng chuyn ha trong mt thit b phn ng dng ng c th tch V.


68/72


b- Mc song song

i vi cc thit b phn ng dng ng mc song song, s phn phi nguyn liu

phi m bo sao cho thnh phn ti mi nhnh l ging nhau, ngha l t s V/F hay thi

gian lu mi nhnh l bng nhau.

Nh vy, vi j thit b phn ng dng ng c th tch l Vi (i = 1 j ) mc song

song s cho chuyn ha ng bng chuyn ha trong mi thit b phn ng v lu

lng ca tc cht np vo h thit b phn ng s bng tng lu lng u vo ca cc

tc cht ca j thit b phn ng.

4.4.7.2Thit b phn ng khuy trn bng nhau mc ni tip (thit b phn

ng nhiu ngn)

Xt j bnh phn ng khuy trn bng nhau mc ni tip. Gi s = 0

a- i vi phn ng bc mt

Phng trnh cn bng vt cht cho bnh phn ng th i vit cho cu t A l :

( )( )

iAi

Ai

Ai

AiAi

Ai

Ao

Ai

Ao

AiAo

i

A

AiAiAoi

Ao

iAoi

kC

C

kC

CC

kC

C

C

C

CC

hay

rxxC

vV

FVC

+=

=

=

===

1

11

1

1

1

1

.

Vi thi gian lu l ging nhau cho tt c j bnh phn ng khuy trn c th tch Vi bng

nhau. Do :

( )jiAj

Aj

A

A

A

Ao

AjAj

Ao kC

C

C

C

C

C

xC

C+==

= 1.....

1

1 1

2

1

1

Vit cho c h vi j bnh phn ng khuy trn :


69/72


70/72


Vi thit b dng ng : += kCC

CAo

A

Ao 1

Kt quc biu din trn hnh (4-8)

V d : Mt bnh phn ng dng khuy trn c chuyn ha l 90% tc cht A thnhsn phm theo phn ng bc hai. Ta dnh thay bnh ny bng hai bnh c tng th tch

bng th tch bnh trc.

a- Vi cng chuyn ha 90%, nng sut s tng bao nhiu ?b-Nu gi nguyn nng sut nh trng hp mt bnh, chuyn ha s tng bao

nhiu ?


71/72


c- Gi s ta mc ni tip bnh th nht vi mt bnh th hai c cng th tch. Vi cng chuyn ha, nng sut s tng bao nhiu ?

d- Vi cng nng sut, chuyn ha tng bao nhiu ?Gii :

a- Vi cng chuyn ha 90%, nng sut stng bao nhiu ?Thay bnh phn ng dng khuy trn bng hai bnh c tng th tch bng th tch

ca bnh u v cng t chuyn ha bng xA = 90% 1 - xA = 0,10. S dng hnh

(4-8) cho phn ng bc hai, ta tra c :

310 1j1j =

=

= ==

va:1jVi

33,33

10

FV.C

FV.C

2jAo

Ao

1jAo

Ao

1j ==

=

=

=

=

=

2j

:oDo

( )

( )33,3

F

F

1jAo

2jAo =

=

=VvaCcungVi Ao

Nh vy, vi cng chuyn ha l 90%, nu thay mt bnh bng hai bnh c tng

th tch bng th tch ca bnh u th nng sut s tng thm 2,33 ln hay 233%.

b-Nu gi nguyn nng sut nh trng hp mt bnh, chuyn ha s tng baonhiu ?

Vi nng sut khng i cho cng th tch bnh nn k, khng i ng

k.CAo. chnh l ng k.CAo. = 90 trong trng hp mt bnh (j = 1) t chuyn hal 90%. ng k.CAo. s ct ng j = 2 ti im 1 - xA = 0,046 xA = 95,4%.

Nu thay 1 bnh bng 2 bnh c tng th tch bng th tch ca bnh u m vn

gi nguyn nng sut nh trng hp 1 bnh th chuyn ha s tng thm 5,4%.

c- Gi s ta mc ni tip bnh thnht vi mt bnh thhai c cng th tch. Vi cng chuyn ha, nng sut stng bao nhiu ?


72/72


Nh trong cu a, ta xc nh c :

( )

( )66633322

333

1

212

2

1

,,:Vi

,

===

=

=

===

=

=

jAo

jAo

jj

j

j

F

FVV

Vy, nng sut tng thm 5,66 ln hay 566%.

d- Vi cng nng sut, chuyn ha tng bao nhiu ?Vi mt bnh t chuyn ha 90%, t hnh (4-8 ) ta tra c : k.CAo. = 90.

Vi hai bnh phn ng th thi gian lu s tng gp i k.CAo. = 180. ng ny s

ct ng j = 2 ti im 1 - xA = 0,026 xA = 97,4%.

Nh vy, chuyn ha tng thm 7,4%.

nguyenlyhoacongnghiep

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