System aspects of biomass gasification with methanol synthesis - Process concepts and energy analysis

A systematic analysis of interrelations between different process steps in the biomass gasification and methanol synthesis chain was made. The energy performance of the system is assessed by reviewing previous studies and analysing a case study. Implications of technology choices and process integration opportunities are in focus. The case study analyses the impact on the energy balance of process-integrated drying compared to import of dried biomass, effects on electricity production due to heat pump integration or district heating (DH) delivery, effect on methanol yield of hydrogen addition and the impacts of adding an methanol-to-olefins (MTO) process. The biomass drying has significant impact on the overall energy balance, the cooling demand increases by 60% for the case study installation when process-integrated drying is not applied for drying the biomass. There is a trade-off between methanol yield, electricity and DH production potential of the system. Heat pumping can increase the electricity yield of the system. Hydrogen addition replacing the water gas shift can increase the methanol yield, in our case study by similar to 35%, but in a stand-alone case the electricity demand makes such a system unrealistic. Adding an MTO unit to the system has limited impact on the energy balance. (C) 2012 Elsevier Ltd. All rights reserved.