Modeling and estimating kinetic parameters for CO₂ methanation from fixed bed reactor experiments

Abstract

CO 2 methanation, which converts CO 2 and hydrogen into methane as fuel, is one of the promising candidates for the development of CO 2 utilization technologies. Recently, a highly active catalyst made of Ni/ZrO 2 for methanation has been developed, and is currently investigated as a potential use in a highperformance reactor. However, design of reactor must be carried out carefully, since this reaction is highly exothermic, which may cause reactor runaway and deterioration of catalysts. For this problem, a mathematical model that can predict the behavior inside the reactor is necessary. In this work, we consider the methanation reaction of CO 2 in a reactor model and estimate the kinetic parameters in the reaction rate model from experimental data. In the parameter estimation using literature values and Tikhonov regularization, eight kinetic parameters in the rate equations were identified from 64 data points with a wide range of conditions. We confirm that molar fractions at the reactor exit predicted by this reactor model are in good agreement with the experimental results. Furthermore, the developed model was validated to predict the compositions and temperature that were not used in the estimation. We expect the developed model will be a powerful tool for the reactor design.