Modelling and optimization of methanol synthesis from hydrogen and CO2

Abstract

In this paper, CO2 hydrogenation to methanol is investigated with three objective functions, i.e. maximization of reactor productivity, CO2 utilization, and hydrogen conversion. Key performance indicators of methanol production via conventional and CO2 hydrogenation routes are compared.The results suggest that the methanol production rate with an inlet H2/CO2 of 3 is ca. 59 % greater than the case with the inlet H2/CO2 composition of 2. The overall hydrogen and CO2 conversion of the cases with the inlet H2/CO2 of 3 is greater than the reactor system with the inlet H2/CO2 of 2.For each objective function criteria, the analysis shows that increasing the H2/CO2 to the methanol reactor increases the natural gas consumption in the conventional route and the higher the inlet H2/CO2 ratio, the higher the CO2 emission is. If the inlet hydrogen is produced via water electrolysis, the CO2 emission of the CO2 hydrogenation process route will be negative.