Machine learning and process modeling of high moisture biomass gasification in downdraft gasifier
Biomass gasification is a potential pathway for thermochemically generating renewable producer gas,which serves as a good substitute fuel in heating and electricity section and is beneficial to the reduction of greenhouse gas emission.Biomass feedstock varies significantly in its composition,especially the content of moisture,posing a challenge for biomass gasification process design and operation in practice,however few research were carried out to elucidate the gasification principles of biomass with different moisture content.In this research,the effects of moisture content and process parameters on biomass gasification characteristics including syngas quality and energy balance are investigated by adopting machine learning and process modeling approaches.The prediction accuracy of the two approaches is first validated by comparing with experimental data.The obtained results indicate that the moisture content of biomass has a great negative impact on the low heating value(LHV)of produced gas,but does not significantly affect the carbon conversion efficiency(CCE)in the downdraft gasifier.The LHV of the produced gas decreases when the air equivalence rate(ER)increases due to the increment of carbon dioxide in the producer gas,but CCE increases with the increase of ER.The energy balance analysis suggests that ER increase with the increment of moisture content in biomass in order to maintain energy balance of the system.Pretreatment of biomass by drying is favorable to maintaining the quality of syngas,but the tradeoff is to consume a certain amount of producer gas to supply heat for the drying process.The consumption rate of the producer gas increases as the moisture content of biomass goes up,which is characterized by a nearly linear increase with the moisture content in the range of 20wt％～60wt％and an exponentially increment as the moisture content goes up beyond 60wt％.The current research provides fundamental insights on gasification characteristics of biomass with different moisture contents.
NETL
NSTL
万方数据
维普
