Thermodynamic analyses of an integrated biomass gasification and solid oxide fuel cell system.

An integrated process of biomass gasification and a SOFC is investigated using energy and exergy analyses. The performance of the system is assessed by calculating several parameters such as electrical efficiency, combined heat and power efficiency, power to heat ratio, exergy destructions and losses, and exergy efficiency. A performance comparison of power system for different gasification agent is given by thermodynamic analyses. When using enriched oxygen as gasification agent, the gasifier reactor caused the greatest exergy destruction. About 32% of the chemical energy of the biomass is converted into net electric power, while about 37 % of it is used to for producing hot water for district heating purposes. The total exergy efficiency of combined heat and power is 35%.For the case in which steam as the gasification agent, the highest exergy destruction lies in the preheater due to the great temperature difference between the hot and cold side. The net electrical efficiency is about 43%. The energy and exergy combined heat and power efficiency are almost 72% and 43%, respectively, which is higher than that when air or enriched oxygen as gasification agent.