Numerical Simulation Of Methane Combustion And NO_x Emission Characteristics Ander Oxygen-enriched Combustion

Sustainable development is the focus of global attention,and energy structure reform is imminent.Oxygen-enriched combustion technology is an efficient energy saving and emission reduction technology,which can organize combustion well,ensure the smooth combustion process and improve combustion thermal efficiency.However,under the condition of oxygen-enriched air combustion,the increase of flame temperature will lead to a rapid increase in the production of thermodynamic NO_X,so it is necessary to study the feasibility of oxygen-enriched humidification measures to reduce the concentration of NO_X.In this paper,CFD FLUENT is selected as the research tool and numerical simulation method is used to study the combustion and NO_X emission characteristics of methane under oxygen-enriched combustion.The characteristics of high-speed gas burner,blunt body burner and baffle burner are analyzed,and four different burners are designed according to their advantages.The high-speed gas burner with the best comprehensive performance is determined on the condition that the fuel can be fully burned and the emission standard of pollutants can be met.The combustion law of methane in the selected burner was studied.The results show that with the increase of oxygen concentration in oxidizer,the overall temperature level in the burner increases,and the temperature in the second half of the burner tends to be uniform,and the combustion efficiency increases.With the increase of oxygen content in oxygen-enriched air,the concentration of NO_X in burner also increases.When the oxygen ratio was 21%,the concentration of NO_X was 66.6113 ppm.When the oxygen ratio increased to 30%,the concentration of NO_X increased to 5313.1390 ppm.In this paper,the combustion and NO_X emission characteristics of methane under different oxygen ratios at humidity levels of 0,100,200 and 300(g/kg)were studied.The results show that the overall temperature decreases with the increase of moisture content,and the distribution of temperature field tends to be uniform,and the heat transfer efficiency increases with the increase of oxygen concentration.When the moisture content is between 0and 100(g/kg),the temperature decreases most.The distribution of NO_X concentration field is basically the same as that of temperature field,and with the increase of moisture content,the emission of NO_X has been well suppressed.