Optimized Process for Methanol Production via Bi-reforming Syngas

In this work, an optimized process for methanolproduction using syngas from bi-reforming is proposed. The feed ratio(CH4/CO2/H2O) in the bi-reforming step, the purge stream quantity,and the heat recovery were optimized with the overall objective toreduce direct and indirect CO2emission in the process. The effect of thefeed ratio on the rates of simultaneous reactions involved in bi-reforming(i.e., DR, SMR, and WGS) was investigated to understand the balancebetween the consumption and production of CO2relative to CH4.Compared to the conventionally used feed ratio of 3:1:2, this studyfound that the 1:1:2 ratio resulted in 100% CH4conversion and higherCO2consumption per mole of CH4in the bi-reforming step. A plant-wide heat integration approach was adopted using pinch analysis todesign a network of 27 heat exchangers. The implementation of a heatexchanger network resulted in the recovery of 221 MW of heat fromprocess streams within the plant. With complementary optimization strategies, the proposed process resulted in similar to 0.31 tonnes ofCO2per tonne of methanol production, one of the lowest among the processes published in the literature