Evaporator - Multiple stage

7/25/2019 Evaporator - Multiple stage

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Simulation of a multiple-effect evaporator

Instructions

2. For a forward feed 2-effect evaporator

In the spreadsheet "2-Effect"

a. Insert parameter values in the yellow cells

b. Turn the "SWITC" ! #set the value in the cell $% #red cell& e'ual to (&

c. Iterate #by pressin) *%& until "*IIS" or "+,+" si)nal is shown in the control panel

in cells $2/ or $2% respectively and start a)ain from 2b

in cells $2/ or $2% respectively and start a)ain from 2b f. When "*IIS" is shown in the control panel0 read the results in the )reen cells #$1-$1

and repeat steps 2a to 2f

h. To recalculate for different parameter values turn the "SWITC" !** #set the value in th

3. For a forward-feed 4-effect evaporator

In the spreadsheet "-Effect *orward"


b. Turn the "SWITC" ! #set the value in the cell $% #red cell& e'ual to (& c. Iterate #by pressin) *%& until "*IIS" or "+,+" si)nal is shown in the control panel

in the cells $2/ or $2% respectively and start a)ain from 2b


f. When "*IIS" is shown in the control panel0 read the results in the )reen cells #$11-$1

and5or 6(% and repeat steps 2a to 2f


4. For a backward-feed 4-effect evaporator

In the spreadsheet "-Effect $ac7ward"


b. Turn the "SWITC" ! #set the value in the cell $% #red cell& e'ual to (&

c. Iterate #by pressin) *%& until "*IIS" or "+,+" si)nal is shown in the control panel

1. a. !n the Toolsmenu0 clic7 Options0 then clic7 the Calculationtab and tic7 on theterati

d. If a si)nal to "E89CE Tsor m

win" is shown in the control panel0 turn the SWITC !**0

e. If a si)nal to "ICE+SE Tsor m

win" is shown in the control panel0 turn the SWITC !*

). If a solution can not be reached under any combination of Ts

and mwin

values0 chan)e th





). If a solution can not be reached under any combination of Tsand m

winvalues0 chan)e th


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f. When "*IIS" is shown in the control panel0 read the results in the )reen cells #$11-$1

and5or 6(% and repeat steps 2a to 2f






). If a solution can not be reached under any combination of Tsand m

winvalues0 chan)e th


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/&

e cell $% e'ual to 3& and repeat steps 2a to 2f

4&


onbo;. !n !a"imum iterationsbo; write (333

reduce the value of either Tsor m

win

0 increase the value of either Tsor m

win

e heat transfer area in the cells (% and5or :(% and5or (%


win


win

e heat transfer area in the cells (% and5or :(% and5or ,(% and5or (%


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4&



win


win

e heat transfer area in the cells (% and5or :(% and5or ,(% and5or (%


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T#e followin$ assumptions are used

(& The pressure drop in the vapour lines is ne)lected

2& The effect of superheatin) on the vapour enthalpy due to the $ation of water0 7:57)

f& ?apour pressure of li'uid water0 atm #ef. (=&

1& The heat losses to the environment are ta7en into account. If cells $21 or $2 for 9los and

a& eat capacity of li'uid foods #e'uation of 8ic7erson&0 :57)oC

where ;wis the mass fraction of water content

b& $oilin)


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where with T in Kelvin=273 .16

T


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o,are set e'ual to 30 the heat losses are ne)lected

)+0. 42873x 103 (104.76955 (1 )1 )2.2195983


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Forward-Feed 2-%ffect %vaporator

Control panel

SWITC@ (

F&S'%(

3.333

nput data

(3333 7)5h

(3A

13A

43

23

3

=3

2=

Control variables

(22

1/133 7)5h

)esults

1112 7)5h

13.3A

1%14 7)5h

Steam economy (.4 7)57)

1/133 7)5h

*eed flow rate0 mf@

*eed solids content0 ;f@

8esired product solids content0 Bspec

@

*eed temperature0 Tf@ oC

Temperature of the environment0 Te@ oC

!verall eat transfer coeffic. for heat losses0 9los

@ W5m2oC

!utside +rea of each effect of the evaporator0 +o,@ m2

Coolin) water temper. at the inlet of the cond.0 Twin@ oC

Steam temperature0 Ts@ oC

ass flow rate of coolin) water in the conden.0mWin

@

Concentrated product flow rate0 mp@Solids content at the outlet0 ;

p@

Steam consumption0 ms@

Coolin) water flow rate0 mWin

@


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*arameters 1st %FF%CT 2nd %FF%CT C

/3 /3 eat transf. area

(/33 (333 !veral heat transf. coef.

2.44/ (./4/ Coolin) water flow rate in

3.( 3.(/ Coolin) water temper. in

43 (3=.1 Water vapour temper. in

(3=.1 4%./ Coolin) water temp. out

(3=.3 4%.2 Condensation temperat.

Saturation pressure #atm&0 < (.(% 3.=1 Water vapour pressure

(.4 2=.2

3.1 3.

1%2% 1/3%

1/3% 124

3 3

3./%% 3.%=1

(./4/ 3.%2=

3.(/ 3.133

(.3% 3./%%

(22 (3=.3

eat transfer area #m2&0 +

!verall heat transfer coef. #W5m2oC&0 9

,i'uid flow rate at the inlet #7)5s&0 mi

Solids content at the inlet0 ;i

,i'uid temperature at the inlet #oC&0 Ti

$oilin) temperature #oC&0 Tb

Saturation temperature #oC&0 Tv

Temperature drop #oC&0 D

$oilin)


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&(%&S%)

=3

2=33

(3.1% 7)5s

2=

4%.2

4.=

4%.(

3.=2 atm

m2

W5m2oC

oC

oC

oC

oC


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Forward-Feed 4-%ffect %vaporator

Control panel

SWITC@ (

F&S'%(

3.3333

nput data

23333 7)5h

%A

/A

3

23

3

=3

2=

Control variables

4=

=13333 7)5h

)esults

14= 7)5h

4.%A

2 7)5h

Steam economy 1./ 7)57)

=13333 7)5h

*eed flow rate0 mf@



@




@ W5m2oC





@

Concentrated product flow rate0 mp@

Solids content at the outlet0 ;p@



@


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1st %FF%CT 2nd %FF%CT 3rd %FF%CT 4t# %FF%CT

243 243 243 243

2233 (/33 (133 =3

=.== ./( 1.142 2.213

3.3% 3.((2 3.(/ 3.22

3 43. =.3 =4.1

43. =.3 =4.1 14.(

43.2 .4 =.% 1=.4

Saturation pressure #atm&0 < 3.1(3 3.2 3.(43 3.3=/

. =.2 4. (%./

3.2 3.1 3. (.

1%= 1%33 1/3/ 1(/

1%33 1/3/ 1(/ 2%4%

3 3 3 3

(.34= (.(3% (.(2 (.(//

./( 1.142 2.213 (.32

3.((2 3.(/ 3.22 3.4%

(.(4% (.34= (.(3% (.(2

4= 43.2 .4 =.%









$oilin)


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CO&(%&S%)

eat transf. area (=3

!veral heat transf. coef. 2=33

Coolin) water flow rate in (4.2 7)5s

Coolin) water temper. in 2=

Water vapour temper. in 1=.4

Coolin) water temp. out 2%.4

Condensation temperat. 1=.4

Water vapour pressure 3.3=/ atm

m2

W5m2oC

oC

oC

oC

oC


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+ackward-Feed 4-%ffect %vaporator

Control panel

SWITC@ (

F&S'%(

3.333

nput data

23333 7)5h

%A

/A

3

23

3

=3

2=

Control variables

4=

223333 7)5h

)esults

14= 7)5h

/.(A

124 7)5h

Steam economy 1./ 7)57)

223333 7)5h

*eed flow rate0 mf@



@




@ W5m2oC





@

Concentrated product flow rate0 mp@

Solids content at the outlet0 ;p@



@


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1st %FF%CT 2nd %FF%CT 3rd %FF%CT 4t# %FF%CT

243 243 243 243

(2( (33 (243 (3

2.232 1.1(2 .1=3 =.==

3.224 3.(=( 3.((= 3.3%3

=4.4 %. 3.= 3.3

.= =4.4 %. 3.=

.% =4.2 %.1 3.1

Saturation pressure #atm&0 < 3.2 3.(41 3.((/ 3.34

/.= 4.2 4.4 /./

(. 3. 3.1 3.2

1(( 1/3( 1/%2 1%=

2%4 1(( 1/3( 1/%2

3 3 3 3

(.(2 (.((3 (.314 (.23

(.33 2.232 1.1(2 .1=3

3./( 3.224 3.(=( 3.((=

(.232 (.(2 (.((3 (.314

4= .% =4.2 %.1









$oilin)


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CO&(%&S%)

eat transf. area (=3

!veral heat transf. coef. 2=33

Coolin) water flow rate in (.( 7)5s

Coolin) water temper. in 2=

Water vapour temper. in 3.1

Coolin) water temp. out 1.

Condensation temperat. 3.2

Water vapour pressure 3.34 atm

m2

W5m2oC

oC

oC

oC

oC


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Documents

Evaporator - Multiple stage