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Chemical Engineering - Chemical Reaction Engineering - Discussion

Discussion Forum : Chemical Reaction Engineering - Section 10 (Q.No. 42)
Chemical Reaction Engineering
42.
For a first order isothermal chemical reaction in a porous catalyst, the effectiveness factor is 0.3. The effectiveness factor will increase if the
catalyst size is reduced or the catalyst diffusivity is reduced.
catalyst size is reduced or the catalyst diffusivity is increased.
catalyst size is increased or the catalyst diffusivity is reduced.
catalyst size is increased or the catalyst diffusivity is increased.
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
5 comments Page 1 of 1.
Chayanika said:   6 months ago
Firstly it falls intermediate of SPDR AND WPDR.
So effectiveness is directly proportional to diffusivity and inversely proportional to the length or diameter of the catalyst.
So according to it, decreasing the size of the catalyst and increasing the diffusivity will help.
Dev said:   3 years ago
B is correct as for first order reaction the Effectiveness (e) is inversely proportional to Thiele modulus. That means e is directly proportional to Diffusivity and inversely proportional to size.

Therefore as size is decreased and Diffusion is increased the e increases.
Mohsin said:   5 years ago
Catalyst size reduces mean surface area increases and diffusion may occur fast so option B is right.
Khan said:   6 years ago
Option D is the right answer.
Dev said:   8 years ago
Describe the reason.
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