CHEN3010 Lecture Notes - Lecture 9: Rate Equation, Packed Bed, Volumetric Flow Rate
Chemical Reaction Engineering
CHEN3010/5040
Semester 1/2018
Collection and Analysis of Rate Data
Fogler Chapter 7
Lecture 3
Gia Hung Pham
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Part 2
Heterogeneous Reaction
Fluid-solid reacting system
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Packed bed reactor (PBR)
PBR is commonly used for heterogeneous reaction.
0L
0
Catalyst bed
A , B
Feed
Product
L
C [mol/l]
CA0
CAE Reactor length [m]
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Document Summary
We measure the concentration of the reactants at the reactor inlet (feed) and reactor outlet (product). Because of the concentration gradient in the pbr, the concentration-time data from the pbr are not suitable for reaction rate law study. Isothermal is difficult to meet with pbr. Axial and radial temperature gradients are usually present in pbr. We use differential reactor to avoid the concentration and temperature gradient, so that the measured data can be used for rate law study. Very small amount of solid catalyst is used for reaction rate study. * very small axial and radial temperature gradient. Simplification for reaction rate study: ignore concentration and temperature gradient. Reactor as a concentration and temperature gradientless reactor: we use high volumetric flow rate and small catalyst particle to avoid mass transfer limitations. (overall reaction rate is affected by chemical reaction rate and mass transfer rate) Because ca0 cae , we can treat the reaction rate as a function of ca0 r.