CHBE 550: Deriving Rate Expressions
S.A. Baldwin
September 16, 2013
1
Reversible reactions
Deriving the rate expression for a rst order reaction:
A
k1
Q
k2
The stoichiometric coecient is one in each c
Heterogeneous reactors
More than one phase: gas, liquid and/or solid
Commonly a solid catalyst provides a surface on which reactions take place
bulk phase is a uid (liquid or gas)
Considerations th
CHBE 550
S.A. Baldwin
September 9, 2013
1
Systematic reactor design: stoichiometry
Mathematical formulation of the stoichiometric equation:
N
i,j Aj = 0
j=1
where is the stoichiometric coecient for ch
37
Dispersion in a tubular reactor with laminar flow
The Text considers the situation where both axial and radial
diffusion can occur in a tubular reactor with laminar flow (i.e. a
parabolic velocity
26
Axial Dispersion Model
The other common model for intermediate degrees of mixing
between PF and perfect mixing is the axial dispersion model.
This model considers the mixing to be analogous to mo
1
Non-Ideal Mixing in Reactors
So far we have considered continuous flow reactors to be in
either (a) plug flow (no mixing: all elements spend identical
times in reactor) or (b) perfect mixing (CSTR: