Evaluation of catalytic effects in gasification of biomass at intermediate temperature and pressure. II Process performance analysis

This paper examines the process performance of biomass gasification to methane. Three gasification configurations were studied via process modeling: the (product) recycle, the (secondary) methanation, and the combined (recycle and methanation) mode. The simulations gave insight into the higher heating value efficiency to methane and the process energy demand (hot utility) with varying gasifier temperature (700–800 °C) and pressure (1–35 bar). Simulation results show that the overall efficiencies to methane obtained are in the range of 48–66%, of which the combined configuration exhibits the highest overall efficiencies (55–66%). Operation without extra heat input (hot utility) is possible for some cases, but only if the energy requirements for the CO2 separation unit are lower than 2 MJ/kg of CO2 via an improved or new CO2 separation technology.