Numerical Simulation Research Of Vortex Gasification Of Biomass Char

China's biomass resources are abundant and widely distributed.Biomass conversion technology can use biomass energy flexibly and efficiently.Among them,gasification technology is one of the main methods.We vigorously develop biomass gasification technologies to solve energy shortages and environmental pollution.The problem is of great significance.However,the commonly used biomass gasification technology has problems such as high gas content of tar and secondary pollution of wastewater.In this paper,based on biomass segmented high-temperature pyrolysis gasification technology that can increase gasification efficiency and effectively reduce tar yield,taking rice husk as an example,the gasification characteristics and biomass of biomass pyrolysis products of major graduate students Flow characteristics in a coke vortex gasifier.This thesis first uses the process simulation software Aspen Plus to establish a biomass pyrolysis gasification process for a 1MW internal combustion-type generator set and perform simulation calculations.The influence of the pyrolysis temperature on the product,and the influence of three gasifying agents of air,water vapor,air and water vapor mixture on the coke gasification products of biomass were studied.The results showed that the pyrolysis yield and the pyrolysis gas production value gradually increased with the increase of temperature when the pyrolysis temperature was between 600°C and 1000°C.When the temperature was higher than 1000°C,the yield and calorific value did not change.obvious.The mixture of air and water vapor as a gasification agent has obvious advantages over other two working conditions.It does not require external heating,and the gasification efficiency and the heat value of gas production can all be at a high level.Based on the simulation results of Aspen Plus,the basic structure of a horizontal vortex gasifier was designed.FLUENT software was used to study the effects of different number of inlets and aspect ratio of the furnace on the flow field in a horizontal vortex gasifier.The results show that the flow field in a single inlet furnace furnace is turbulent and the speed attenuation is large,but the flow field in the furnace with double inlets is symmetrical and the tangential velocity is obviously incr eased,which is more conducive to the rotation of the particles.When the ratio of length to diameter is 1.1-2.3,the tangential velocity at different cross sections in the furnace decreases with the aspect ratio increasing,and the particle residence time gradually increases.For the 1mm particle size biomass coke particles,the gasification agent When the inlet velocity is 80m/s and the aspect ratio is 2,the average particle residence time can reach more than 2s,and the pressure drop in the furnace is minimum.Taking the furnace with length-diameter ratio of 2 as the research object,the influence of the gasification agent inlet velocity and the particle size of the biomass coke on the flow field in the furnace was investigated.The results showed that the gasification agent inlet velocity was 40m/s-120m/s,the increase of gas velocity is beneficial to increase the tangential velocity and turbulent kinetic energy at different positions in the furnace,and it is beneficial to the particle-attached rotating motion,but the particle residence time decreases with increasing gas velocity.When the particle size is 1mm-7mm,with the increase of particle size,the tangential velocity at different positions in the furnace tends to decrease.The distribution of pa rticle phase gradually approaches the center of the gasifier,and the average residence time of particles gradually increases.