Biomethanol production via electrolysis, oxy-fuel combustion, water-gas shift reaction, and LNG cold energy recovery

Abstract

The hydrogen economy is of crucial importance in energy policies worldwide. Moreover, there are many benefits to producing biomethanol because it can be used in engines to achieve high efficiency, zero emission and lower risks of flammability. This research aims to evaluate a biomethanol and natural gas generation system that uses biomass gasification and high-temperature electrolysis. Thermal integration is applied between the steam generators of the gasifier and electrolyzer. The LNG regasification unit and an open Brayton cycle are responsible for power and natural gas production. The flue gas leaving the gas turbine leads to additional production of biomethanol. Oxygen management is applied between three different subsystems and there is a large amount of CO2 utilization as well. The results of energy analysis and thermodynamic modelling of an integrated system conducted in Aspen Plus indicate that the proposed cycle produces 16 644 ton/yr of natural gas, 1412 ton/yr of biomethanol, uses 3450 ton/yr of CO2, and has an efficiency of 81.96 %. Raising the methanol reactor temperature from 220 °C to 350 °C significantly enhances biomethanol capacity from 1015 ton/yr to 1930 ton/yr, leading to a 4 % increase in total energy efficiency.