Experimental Research On Biomass Catalytic Gasification Based On Fe-Ce/Dol Catalyst

Climate change caused by the greenhouse effect poses a huge threat to humans and other organisms.Greenhouse gas emissions from some human activities（such as burning fossil fuels for power generation）are the main factors leading to climate change.In order to alleviate this situation,it is necessary to develop from conventional power generation to renewable energy generation,such as solar photovoltaic,wind energy,biomass energy and hydropower generation.The use of biomass energy has certain advantages over other renewable energy sources because it is less dependent on location and climate,and biomass is easy to store and transport.In addition,biomass resources are very rich,relatively even and extensive,and it is the fourth largest energy source in the world after oil,coal and natural gas.At present,rural areas in less developed countries still rely on biomass for cooking and heating activities.At the same time,waste biomass is usually more easily available and can be as useful as low-cost fuel,which makes it a viable and promising energy source.Developed countries also use biomass as a sustainable energy option,because compared with fossil fuels,biomass is abundant and has less impact on the environment.Biomass gasification is a widely used thermochemical method for obtaining products with more value and potential applications than the raw materials themselves.The quality of the products mainly depends on the raw materials,gasification agent,temperature inside the reactor and catalyst and other factors.Due to the increasingly serious environmental problems,biomass gasification has attracted more and more attention worldwide.In order to strengthen the research on biomass gasification,this article uses waste pine wood chips as raw materials,steam as gasification agent,and Fe-Ce/dolomite prepared as catalyst using dolomite as carrier.In the fixed-bed reactor,a pine sawdust steam catalytic gasification experiment was conducted to explore the catalytic performance of the catalyst and optimize the experimental parameters to improve the quality of the biomass product gas.Firstly,dolomite is pretreated by calcination.Compared with natural dolomite before calcination,the surface color of calcined dolomite changes from cyan gray to yellowish white,the main chemical composition is decomposed into CaO and MgO by CaMg（CO₃）₂carbonate crystals,and the surface structure also changed.The BET specific surface area of the calcined dolomite and natural dolomite increased from 1.366m²/g to 8.563m²/g,and the pore volume increased from 0.007cm³/g to 0.098 cm³/g.Suitable as a catalyst carriert.The catalytic activity of dolomite at different calcination temperatures（700℃,800℃,900℃）was compared under experimental conditions.The calcination temperature of dolomite at900℃was better than other temperatures.Secondly,the calcined dolomite was used as the carrier,and the Fe-Ce/dolomite catalyst was prepared by the impregnation method.The catalyst was characterized by SEM、XRD and other means.By comparing the structure and morphology of the catalyst before and after loading,it can be seen that the additive can be well loaded on the dolomite.The catalytic performance of Fe-Ce/dolomite catalysts with different loading of additives is also discussed.It has achieved the highest gas and hydrogen production rates,1.28m³/kg and 46.24g/kg.With repeated use of this catalyst,the volume fraction of hydrogen decreased from 40.34%in the first time to 38.97%in the second time and 34.95%in the third time with the increase in the number of uses,and the catalytic activity gradually decreased.Comparing the morphology of the catalyst before and after the reaction,it can be seen that the amount of carbon on the catalyst surface area gradually increased（the amount of carbon deposit increased from 21.55mg/g for the first time to 31.61 mg/g for three times）and severe scorching,which reduced the catalytic activity.Thirdly,pine wood rods are used as biomass raw materials,water vapor is used as gasifying agent,and Fe-Ce/dolomite（8%Fe-2%Ce）is used as the catalyst in a two-stage fixed-bed reactor.Biomass water vapor catalytic gasification experiments explore the effects of water vapor flow,catalyst presence,gasification temperature,and catalytic temperature on the gasification effect of biomass.The optimal conditions for the biomass water vapor catalytic gasification experiment were obtained:the water vapor flow rate was1g/min,the gasification temperature was 900℃,and the catalytic temperature was800-850℃.At this time,the gas production rate was 1.58m³/kg,the hydrogen production rate was 67.83g/kg,and the volume fraction of H₂ was 46.95%.The significance of this paper is to improve the mechanical strength of the dolomite catalyst.After comprehensive consideration,the optimal gasification conditions under experimental conditions are obtained,which provides a reference for future biomass gasification.