Mathematical modeling of a methanol reactor by using different kinetic models

Abstract

In this research, a mathematical model for an industrial methanol reactor is developed comparing different kinetic models: Graaf et al., Vanden Bussche and Froment, pseudo first order and pseudo zero order. Similar studies have not been carried out previously. The considered reactor is multi-tubular with a methanol productivity of 2061 ton/day. Comparing the results obtained by mathematical models with experimental data, it is evident that only the Vanden Bussche and Froment kinetic model describes the methanol industrial reactor better. Also, it results that for all kinetic models, the effectiveness factor is equal to 1: for industrial reactors at high pressure and low temperature limitation phenomena are not present (the calculated Weis-Prater parameter is equal to 0.03). A sensitivity analysis is developed to analyze the effect of recycling ratio, global heat exchange coefficient, temperature, pressure, tube diameter on carbon conversion and specific heat flux. By increasing the recycling ratio and temperature, carbon conversion decreases, while by increasing all parameters, excluding the recycling ratio, the exchanged heat decreases. Different feeds are also analyzed: coke oven gas allows the highest methanol production, while flue gas and hydrogen from water electrolysis ensure the lowest productivity.