Chemical Reaction Engineering (CRE) is the field that studies the rates and mechanisms of chemical reactions and the design of the reactors in which they take place. Lecture 27
Chemical Reaction Engineering (CRE) is the field that studies the rates and mechanisms of
chemical reactions and the design of the reactors in which they take place.
Lecture 27
Web Lecture 27 Class Lecture 23
How Reaction Rate Varies with: 1. Temperature 2. Catalyst Particle Size 3. Eternal Flow Rate
For A. Reaction Rate Limited Reactors B. Internal Diffusion Limited Reactions C. External Rate Limited Reactions
And all 9 combinations of numbers and letters, Eq. 1A, 1B, 1C, 2A, 2B, 2C and 3A, 3B and 3C.
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Internal Diffusion How will we know these trends discussed in the last slide:
1. Solve the diffusion and reaction equation for catalyst particle for concentration gradient
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CA =CA0λ
Sinh Θ1λ( )Sinh Θ1
2. Find the true rate of reaction as a function of the external and internal surface reactions.
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Internal Diffusion
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D ~ T1.75
kr ~ e−E RT
− "rA =3R
Dekr kr =
3R
De kr
− "rA =~ D0.875e−E 2RT
=
Surface Reaction
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−rA = krCA = k1 expER1T1−1T
"
#$
%
&'
"
#$$
%
&''
− "rA
U
− "rA
dp
− "rA
T
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and − rA = −knCAn
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The Thiele modulus for this first order reaction is
For a first-order reaction, Equation (15-19) becomes
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Figure E15-1.1 Damaged cartilage. (Figure courtesy of Newsweek, September 3, 2001.) 22
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Diffusion of O2 around collagen
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A0
A
CC ,
Lz == ψλ
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