Dynamics Simulation Research About Fast Pyrolysis And Gasification With Water Vapor Of Biomass In Entrained-flow Gasifier

In recent years,biomass gasification has been vigorously developed due to its high efficiency and good adaptability of raw materials,the commercialization of biomass energy has become the research hotspot of this region.This paper studies on the characteristics of biomass gasification through experiment and numerical simulation.A small experimental entrained-flow gasifier was built up,and the experiment about rapid pyrolysis and steam vaporization was taken.The result of experiment shows that the increase of temperature is beneficial to improving the yield of product gas,the carbon conversion rate and gasification efficiency of gasification process,but the temperature will promote CH4 reforming reaction,water gas change reaction,decrease the content of CO and methane,thus affecting the heat value of product gas.Particle size also has some influence on the gasification results by temperature increase rate and final temperature.Small particle size is good for faster temperature increase rate and final temperature.The steam vaporization can increase the content of H2 and CO in product gas as well as the carbon conversion rate and H2/CO ratio.Excessive water vapor will decrease furnace temperature,and influence the chemical reaction rate leading to the decline of product gas quality.In this paper,a model of entrained-flow gasifier was established on the basis of the Ansys 14.5 software.The simulation results show that during the gasification process,gas phase and solid phase is uniformly mixed in the furnace with high heat transfer efficiency and the chemical reaction rate distribution in the furnace is uniform in the gasification process.Reaction rate is sensitive to both concentration and temperature,while temperature has a comparatively greatest influence.Particle size change effects the heterogeneous reaction rate,and S/B change will change the concentration of water vapor in the furnace,which would affect the reaction rate of methane recombination and water vapor conversion.The difference of the reaction rate change in the furnace results in the change of the components content in the product gas.