The Influence of Fuel and Steam Consumption on Characteristics of Fixed Bed Process of Woody Biomass Steam Gasification with Intensive Heat Supply
Keywords:bioenergy, allothermal gasification, mathematical modeling, hydrogen, solar energy
Plant biomass is one of the most widespread renewable energy sources. Energy utilization of biomass allows solving some problems associated with the development of off-grid energy systems and the processing of combustible waste (primarily agricultural and forestry waste). This paper is devoted to the study of an allothermal gasification process of plant biomass materials using a kinetic-thermodynamic model developed by the author. The gasification process is considered stationary, and steam is used as a gasification agent. The power of the supplied heat is considered constant (10 kW). One of the significant tasks related to allothermal gasification is to choose flowrate parameters so that the heat supplied is efficiently used in chemical reactions without the threat of reactor overheating. The determination of the boundaries of the safe gasifier operation involved variant calculations with a view to optimizing the gasification conditions. The calculation results show that the allothermal gasification process can proceed with a thermochemical efficiency of about 70%. For each fixed fuel consumption level, there is an optimal fuel-steam ratio. The complete conversion of biomass requires sufficiently high temperatures. The produced gas contains a significant steam fraction
(>50 vol%) even under optimal conditions. The calculated fraction of hydrogen in dry gas is up to 60vol%. The data obtained can be used to assess the efficiency of energy units with biomass gasification using high-temperature sources, for example, in systems that use and store solar thermal energy.