Determining the effect of the structural and technological parameters of a gas blower unit on the air flow distribution in a gas generator

Abstract

The object of this study is the structural and technological parameters of the gas blower unit in the gasification chamber of a gas generator. The task to enable uniform distribution of air masses in the gas generator has been solved using the ANSYS Fluent software. The study is based on a simulation of the movement of air flows in the characteristic cross-sections of the gas generator, in particular the cross-section of the gasification chamber at the border of the oxidation and reduction zones. Seven structures of the gas blower unit were analyzed, the effectiveness of which was determined by the coefficient of variation. The most effective was the design whose value of the coefficient of variation is the smallest and equal to 93 %. At the same time, the total area of zones with no movement of air masses, that is, the absence of a gasification process, does not exceed 12 % of the total cross-sectional area of the gas generator. The speed of air masses at the boundary of the oxidation and reduction zones is aligned in the entire cross-section of the chamber and is V ≈ 4.5 m/s. The average value of the vertical component of the speed of air masses in the cross-section at the inlet to the recovery zone of the gasification chamber is V ≈ 0.6 m/s. Under such conditions, the production of synthesis gas of high calorific value with the absence of resins, acids, heavy hydrocarbons, and mechanical impurities is ensured. The correspondence of the simulation results with experimental data is confirmed by the coefficient of determination, which amounted to 0.87. The results reported here could be the basis of a modernized methodology for the study of aerodynamic, heat and mass exchange processes that occur during biomass gasification. This would make it possible to define the rational structural and technological parameters of gas generators and improve the efficiency of the gasification process as a whole.