CN2116E Assignment #2 (due 19-04-2013) CN2116E-XJP-2013-Assignment #2

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Name: _________________

Matric. No: _________________

QUESTION 1 (25 marks)

A liquid macrofluid reacts according to RA as it flows through a vessel. Find the conversion

of A for the following flow pattern and kinetics.

Solution

(a) Using the segregation model, dttEtXXbatch

)()(0

For a batch reactor we have

0A

A

C

r

dt

dX

From the reaction kinetics, we have

zero order reaction, minmol/lit 3 Ar and mol/lit 60 AC

Solving for X(t), we have

2minfor t 1,X

min2for ,5.05.0)(

ttXttX

From the flow pattern (a), we have

3t0for ,min3

1)( 1 tE

Therefore, the mean conversion for a zero order reaction is

3

2)

3

1()1()

3

1()5.0(

3

2

2

0 dtdttX

CN2116E Assignment #2 (due 19-04-2013) CN2116E-XJP-2013-Assignment #2

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QUESTION 2 (25 marks)

The rate law for the hydrogenation (H) of ethylene (E) to form ethane (A) over a cobalt-

molybdenum catalyst is

EE

HEE

PK

PkPr

1'

Suggest a mechanism and rate-limiting step consistent with the rate law.

Solution

AEH

HCHCH Cat

62422

Only E adsorb on catalytic surface. Eley-Rideal kinetics.

HSESs

E

SEvEAEADE

CCkrE

K

CCCkrE

SAHS

SSE

Site balance:

)1( EEvSEvT CKCCCC

Therefore

TES

EE

HE

EE

TEEHSs

CKkk

PK

PkP

CK

CCKCkr

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