CHAPTER 4_lecture 2

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CHAPTER 4Isothermal Reactor Design

LECTURE 2

G I V E A M A N S O M E F I S H , Y O U F E E D H I M F O R A D A Y, T E A C H A M A N H O W T O C A T C H F I S H , Y O U F E E D H I M F O R L I F E

- U N K N O W N -



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TopicsLecture 1: Design structure for isothermal reactors

Scale up of liquid phase batch reactor

data to the design of CSTR

Lecture 2: Design of CSTR

Lecture 3: Design of tubular reactors

Lecture 4: Reccle reactors

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Design o C!TR

Recap " single reactor#$Design e%&ation or C!TR

$Constant 'ol&me s(stem)&'&0

*here# F A0'C A0&0

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A

0 A

A

A0 A

%

( F

%

F F V

−=

−−

=

−−

= A

A0 A0

%

C C &V

A

A0 A

0 %

C C

&

V

−

−==τ

) *

C C ,

)C

C C 0 A

A

A

A0 A

τ

τ

+

=−

=

) *

) (

τ

τ

+

=



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Design o C!TR

Dam+ohler n&m,er) Da$-i'es %&ic+ estimate on the .egree o con'ersion

in C!TR

$Da / 01) then / 01

$Da 10) then 0

1st order irreversible

reaction:

2nd order irreversible

reaction:

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0 A

0 A

F

V % Da

−=

) Da τ = 0 A)C Da τ =



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Design o C!TRs 5 C!TR in series

-r A1

V1

-r A2

V2

CA0

CA1,X1

CA2,X2

Information:

1. First order reaction with no volume chane

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**

0 A* A

) *

C C

τ +

=

( )( )**22

0 A

22

* A

2 A) *) *

C

) *

C C

τ τ τ ++

=

+

=

( ) ( )

##

A

A

) (

)

C C

#

τ τ

+

−=

+

=1

11,

1

0



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!um"er of tan#s, n

C"#&e%+!"# a+ a #c!"# " .e #/e% " a#)+ !# +e%!e+ "% !%+ "%1e% %eac!"#

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n 1 2 3 4 7 8 9 : 10

Con'ersion 'ers&s n&m,er o tan+s) n or .i;erent Da< t+

t+<1

t+<07

t+<01

n

1 070 033 002 097 078 019

3 0:: 090 027

4 04 0:0 032

7 09 0:9 03:

8 0: 01 044

9 0 04 04

: 100 08 073 100 09 07:

10 100 0: 081

( ) ( )##

A

A

) (

)

C C

#

τ τ +

−=

+

=

1

11,

1

0



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Design o C!TRs 5 C!TR in parallel

-r A1

V1

-r A2

V2

Assume:1. $%ual reactor si&e

2. 'imilar o(eratin

tem(erature ) feed

rate

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Design o C!TRs 5 C!TR in parallel

I.entical ee. rate) si=e >temperat&re) thereore#

?ol&me o in.i'i.&al reactor

@olar o*rate

Balance on i romin.i'i.&al reactor 'ol&me

similar to single'ol&me

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A

0 A

A!

!0 A

A!

!

!0 A!

%

( F

V

%

(

#

F

#

V

%

(

F V

−=∴

−

=

−=

A A#2 A* A

#2*

% % % %

( ( ( (

−=−==−=−

===

#

V V ! =

#

F F

0 A

!0 A =



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Eample 42# Pro.&ction o eth(lene gl(col in a C!TR

It is .esire. to pro.&ce 200 million po&n.s per (ear o eth(lenegl(colA The reaction ta+es place in an isothermal C!TR an. theollo*ing .ata appliesF

$GA0 < 7: mols

$CA0 < 1 mol.m3 ater miing

$ + < 0311 min51

Pro,lem statement#

$Gin. the 'ol&me re%&ire. or :0 con'ersion in a single

C!TR$ The n&m,er o 3 m3 reactor re%&ire. to achie'e :0

con'ersion i the reactor is arrange. in parallelJ

$ The n&m,er o 3 m3 reactor re%&ire. to achie'e :0con'ersion i the reactor is arrange. in seriesJ

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THE END

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CHAPTER 4_lecture 2