Kinetic Parameters Optimization and Analysis in Packed Bed Steam Methane Reformer

Steam Methane Reformer (SMR) has been in use for several years for generation of H₂ and Syngas needed for different applications. Production of oil is one of such application, where this gas is further fed to Fischer-Tropsch process.

Lab scale experiment has been setup to study kinetics of steam methane reforming over catalyst to obtain kinetic data of reactor modelling. The overall reactions in SMR process is to form CO, H₂, CO₂ and H₂O include number of equations. However, according to thermodynamic analysis of previous studies, only the three important equations are considered in this study. The reaction equilibrium constants of these three equations are evaluated from literature,

Reaction rate expressions for SMR is determined based on the detailed studies of possible mechanisms and appropriate rate controlling steps, which have been presented in this research. It is widely accepted that both methane and steam are adsorbed on the catalyst with dissociation and the surface reactions producing CO and CO₂ are the rate controlling steps. Considering information in the literature and thermodynamics analysis, appropriate forms of reaction rate expressions are considered for the kinetic model. There are four adsorption constants and three rate constants in rate expressions where the temperature dependency of each was estimated. The kinetic parameters were determined by minimizing the squared sum of the error between experimental data and predicted results from catalyst bed model. The values of the parameters for optimal fit were determined using nonlinear regression coupled with nonlinear ordinary differential equation solver.