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Catalysis
Posted May 5, 2017, 5:09 p.m. EDT 1 Reply
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Hello!
I would like to know how to turn the catalyst (any material present) used into a powder in order to get the right calculations. and How to turn the bulk materials in the libraries into small pieces.
Thanks in advance.
I would like to know how to turn the catalyst (any material present) used into a powder in order to get the right calculations. and How to turn the bulk materials in the libraries into small pieces.
Thanks in advance.
1 Reply Last Post May 10, 2017, 1:33 a.m. EDT
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Posted:
8 years ago
Hi
Based on your message, it is not clear what your are catalyzing, but if it is a chemical reaction taking place on the catalyst surface that is dispersed as small particles in a certain volume, I would treat that as a homogeneous reaction term. The catalyst "concentration" would be an apparent one in the reaction rate equation.
A + C --> B
R = k*[A]*[C]
A = reactant
C = catalyst
When the catalyst particles are small enough, mass transport to the catalyst surface is very fast and can be omitted or included in the apparent rate constant k. The correct expression á surface area of the catalyst would be
R' = k*[A]/(1 + k*a/D)
where a is the particle radius (assumed sphere) and D the reactant diffusion coefficient. Hence, if 1 >> ka/D homogeneous reaction is achieved.
BR
Lasse
Based on your message, it is not clear what your are catalyzing, but if it is a chemical reaction taking place on the catalyst surface that is dispersed as small particles in a certain volume, I would treat that as a homogeneous reaction term. The catalyst "concentration" would be an apparent one in the reaction rate equation.
A + C --> B
R = k*[A]*[C]
A = reactant
C = catalyst
When the catalyst particles are small enough, mass transport to the catalyst surface is very fast and can be omitted or included in the apparent rate constant k. The correct expression á surface area of the catalyst would be
R' = k*[A]/(1 + k*a/D)
where a is the particle radius (assumed sphere) and D the reactant diffusion coefficient. Hence, if 1 >> ka/D homogeneous reaction is achieved.
BR
Lasse