
Two isothermal chemical reactors in series are used to carry out the reaction A → B. These reactors can be continuous stirredtank reactors (CSTR) or plug flow reactors (PFR).
The reactor volumes for a continuous stirredtank reactor (CSTR) and plug flow reactor (PFR) are:
,
,
where is the inlet molar flow rate of reactant , is the rate of disappearance of reactant and and are the inlet and outlet reactor conversions.
Assuming constant reactor inlet flow rate , the molar flow rate of is . The concentration of can be written in terms of conversion .
The reaction rates for the different reaction types are:
first order: ,
second order: ,
Langmuir–Hinshelwood: ,
assuming , the Langmuir–Hinshelwood rate law can be written in terms of conversion :
,
where is the rate constant, and and are the adsorption equilibrium constants for and .
Reference:
H. S. Fogler, Essentials of Chemical Reaction Engineering, 1st ed., Upper Saddle River, NJ: Pearson Education, 2010 pp. 33–82, 445.