Process Simulation On High-temperature Gasification Of Biomass With Steam

To alleviate pressure on energy demand, taking into account both economicalefficiency and environmental protection, the research on biomass conversion and utilizeis an urgent issue, Biomass pyrolysis and gasification technology is one of the biomassthermo-chemical conversion technology, which can utilize biomass energy effectively.High temperature biomass pyrolysis and gasification process can increase carbonconversion efficiency in pyrolysis and gasification and decrease tar quantity by the wayof rising up gasification temperature. This process use part of the gas product tocombust in a external burner for producing high temperature anaerobic flue gas burner,providing heat for pyrolysis and gasification process. According to the processsimulation software, this thesis analysis the simulation of biomass pyrolysis andgasification with steam process, this research lay a foundation on the experimentalresearch by providing theoretical reference data.This thesis selects three representative different biomass: rice husk, pine sawdustand straw. Using the Aspen Plus process simulation software to simulate biomasstwo-stage pyrolysis and gasification process. The influence of the gasificationtemperature and the steam-to-biomass ratio on gas production component yield, thecarbon conversion efficiency of biomass and low heat value of gas production areanalysed.Different categories of biomass in simulated conditions have some similarcharacteristics for pyrolysis and gasification. From600°C to1000°C, Increasinggasification temperature can lead to the content of the active ingredient in gasproduction also increases, together with the carbon conversion efficiency rise. The gaslow heat value of pyrolysis and gasification process on gasification temperature of700°C reaches the minimum, followed by gradually increase. The ratio of steam tobiomass quality （H₂O/B） ranges from0to0.35,and increasing the amount of steamintake will improve the hydrogen and the carbon dioxide content. In the certaintemperature range from800°C to1000°C,（H₂O/B） ratio more than0.15, with steamthrough the intake increase, the content of carbon monoxide will decrease. At the givensteam-to-biomass ratio range in this simulation, the increase of the ratio results in thecarbon conversion efficiency of biomass improving and the low heat value of gas production reducing. When the gasification temperature is low and the water content ofthe biomass itself is sufficient, the gasification process may not need to be added anexternal steam.