Determination and Application of Improved Kinetic Parameters for Simulation of Maleic Anhydride Synthesis in Industrial Fixed- Bed Reactor

Abstract

The aims of this study were to determine improved kinetic
parameters in five kinetic models for oxidation of n-butane into
maleic anhydride in an industrial fixed-bed reactor, and to
simulate the reactor performance. On the basis of the measured
process parameters, inlet and outlet concentrations of n-butane
were calculated and then used to fit the kinetic models. The
industrial fixed-bed reactor was approximated by 10 continuous
stirred tank reactors (CSTR) connected in series. Based on the
calculated outlet concentration of n-butane from the industrial
reactor, the outlet concentration of n-butane from the
penultimate reactor was calculated. Then the concentrations of
n-butane were calculated until the inlet concentration of nbutane
in the first reactor was obtained. Kinetic parameters
were determined by comparing the inlet concentrations of nbutane
in the first reactor with the inlet concentration of nbutane
obtained on the basis of the measured process
parameters in the industrial fixed-bed reactor. Kinetic models
with improved kinetic parameters showed better simulation
results compared to kinetic models with the existing kinetic
parameters. The best agreement of simulation results and
measured values was achieved with application of the kinetic
model 2 (Equations (2a-c)). The smallest deviations of
numerical simulation in comparison with measured values of the
outlet pressure of reaction mixture were 0.45, 0.75 and 0.75%
for application of the kinetic model 3 (Equations (3a-c)). The
percentage deviations of numerical simulation with improved
kinetic parameters and the existing kinetic parameters in
comparison with measured values of inside reactor temperature
were in the range 0.90-5.36% and in the range 4.17-9.78%
(kinetic model 2, Equations (2a-c)), respectively.