OPTIMIZATION OF HYDROGEN PRODUCTION FROM METHANOL USING A SORPTION-ENHANCED STEAM REFORMING PROCESS

Abstract

A sorption-enhanced steam reforming is considered to be a suitable process for hydrogen production. By adding solid calcium oxide (CaO) to the reformer, carbon dioxide (CO2) is removed via the carbonation reaction and the yield of hydrogen is improved. The aim of this study was to find the optimal operating condition of the sorption-enhanced steam reforming process using methanol as a hydrogen source. Modeling of the reforming process was done using flowsheet simulator. Kinetics of methanol reforming, methanol steam reforming, methanol decomposition, water gas shift reaction, and carbonation were employed to explain the sorption-enhanced steam reforming. Sensitivity analyses of key parameters of the sorption-enhanced steam reformer were performed to study the performance of the reformer at different operating conditions. Optimization of the sorption-enhanced steam reformer was performed with the objective to find its optimal operating condition by maximizing hydrogen product with the presence of carbon monoxide (CO) less than 10 ppm. It was found that one mole of methanol gave the maximum hydrogen yield of 3 when the reformer was operated at 350 °C and steam-to-methanol molar feed ratio of 1.70. The heat integration of the reforming process was considered to reduce a hot utility requirement and the results showed that useful heat was recovered by 39.16 percents, resulting in the process thermal efficiency of 75.23 percents. A simplified profit estimation and economic analyses were carried out based on on-site reforming at a refuelling station. The estimation showed profit at 37.13 percents based on competitive selling price of hydrogen, comparing to gasoline selling price.