pengendalian penukar panas

7/25/2019 Pengendalian Penukar Panas

http://slidepdf.com/reader/full/pengendalian-penukar-panas 1/5

Variabel Sistem Pengendalian Penukar Panas

Control Objective T = Tss

State Variable T (Temperatur)

Output Variable T

Input (disturbance) TC (laju alir fluida dingin)

Input (manipulated) ! ("aju air pemanas)

Parameter Cp# $# p

%onfigurasi eed back

$nalisa &erajat %ebebasan Sistem Pengendalian Penukar Panas

Variabel Terlibat C# !# TCin# T!# TCout ' eraca massa dan energi dT*dt +,

Variabel diketa-ui C# T!# TCout +.

Variabel dimanipulasi ! +,

$&% /

$sumsi+asumsi 0

"aju alir fluida dingin konstan

Temperatur fluida panas konstan

Cp# µ # ρ metanol konstan pada rentang su-u operasi

&ata+data 1ang digunakan dalam pengendalian ini adala- (conto- kasus !2+3/,)

• Tekanan operasi# P = , atm

• Temperatur air panas# T! = ,// oC

• &ensitas air panas# ρ a = 45 kg*m.

• &ensitas metanol# ρ m = 676 kg*m.

• %apasitas panas metanol# Cpm = ,#,8,/ 9*kmol %

• %apasitas panas air# CPa = 6#38,/5 9*kmol8%

• Temperatur metanol keluar keadaan tunak# Tss = 6.#. oC

• "aju alir metanol# = 6#5:8,/+5 kmol*s

• &imensi alat 0 panjang = :#.5 m



&in = :/#3 mm

Neraca Massa

( )= +in out

d mm m

dt

( )= +in out

dρV ρF ρF

dt

$kumulasi massa /=)(

dt

V ρd

$sumsi densitas tetap#

out in F F = (,)

Neraca Energi

= + 'in out

dH H H Q

dt

( )( ( + )

= ( + ) + ( + ) ' +m m C C m m C Cout a H H ref

dρCpV T Tref ρ Cp F T Tref ρ Cp F T Tref ρ F T T

dt

Tref = / ;

= + 'm m C C m m C a a H H

dT ρCpV ρ Cp F T ρ Cp F T ρ Cp F T

dt (:)

Substitusi persasaam (,) ke persamaan (:)

= + 'C C a a

C H

m m

F Fρ CpdT T T F

dt V Vρ VCp(.)

Stead1 state 0

C C#ss

! !#ss

dTss/

dtT Tss

T T

=

==

=

# #= + 'C C a a

C ss ss H ss

m m

F Fρ CpdT T T F

dt V Vρ VCp(5)



Persamaan (.) < (5)

# #

( + )= ( + ) + ( + ) ' ( + )

ss a a

C C ss ss H H ss

m m

d T Tρ Cp F F T T T T F F

dt V Vρ VCp

= + ' a a

C H

m m

ρ CpdT F F T T F

dt V Vρ VCp

"aplace 0

a aC !

m m

Cp

sT (s) T (s) T (s) (s)V V VCp

ρ

ρ + = +

( ) ( ) ( ) ρ

ρ

+ = + ÷

a aC H

m m

Cp F F s T s T s F s

V V VCp

Fungsi Trasnfer :

( ) ( )

,( ) = ( ) ' ( )

' '

F V a a

C H F F V V m m

ρ CpT s T s F s

ρ VCp s s()

Fungsi Transfer disturbance (Gd) :

( ) ,= = =

( ) ( ' ) ( ',)

,=

,,#47 ',

F V

V F V F C

T sGd

T s s s

Gd s

(3)

Fungsi transfer proses (Gp) :

( )

( ) ,= = =

( ) ( ' ) ',

:73#:=

,,#47 ',

V F a a a a

F V V F H m m m m

ρ Cp ρ CpT sGp

F sρ VCp s ρ VCp s

Gp s



Tanpa pengendali

&engan PI Controller

pengendalian penukar panas

Documents