Design And Numerical Simulation Of Low NO_x Natural Gas Burner

As national vigorously promote the work of coal to gas,the transformation of industrial boiler industry will face a huge challenge,ordinary coal-fired boiler to gradually transition to the gas boiler,composition and gas boiler combustion produces the most pollution is nitrogen gas,to reduce nitrogen oxide emissions,to popularize the use of low nitrogen gas burners,but domestic low nitrogen burner foreign monopoly,the market has been the imports of low nitrogen gas burner not only expensive,and implement the technology blockade.The low nitrogen combustion technology is backward in China.The independent development of low nitrogen burner can not only break through the foreign market monopoly and improve the scientific and technological competitiveness,but also reduce the environmental pollution in the combustion process and improve the economic benefits.Natural gas,as a kind of clean energy,is almost free from sulfur oxide and dust pollution in the combustion process,so it has natural advantages in the combustion of industrial boilers.Therefore,most research work now focuses on how to reduce the nitrogen oxide pollution generated in the combustion process of natural gas.The purpose of this paper is to design a new type of low-nitrogen gas burner,so as to reduce the emission of nitrogen oxides in the process of natural gas combustion,so as to provide enterprises with low-nitrogen efficient industrial boiler burners,and actively practice the mainstream development of green environmental protection.At the request of a combustion equipment enterprise in Hebei,a natural gas low nitrogen burner with a combustion capacity of 100m~3/h was designed.In this paper,the burner provided by the enterprise is used as a prototype to conduct 3-D modeling,meshing and numerical simulation of the burner.In the selection of mathematical model,the model and mechanism were verified by the experimental data of American Sandia Flame D Flame,and reliable chemical reaction model,turbulence model and combustion mechanism were obtained.On this basis,this paper designed the four new burner structure,and the combustion reaction of simulation analysis,respectively,in terms of speed of temperature and related components and the comparison of the simulation results of prototype burner,ultimately determine the burning effect is the most ideal,the lowest NO_xemissions of burner,NO_xemissions of 30.6 PPM,a prototype burner was reduced by34.1%.Then researches on the performance of the burner,six different excess air coefficient is studied respectively,5 kinds of different air preheating temperature,the center of the five different air volume,velocity field and temperature field in the burner NO_x concentration field distribution rule,determine the optimum excess air coefficient and preheating air temperature,the center values range,provides a reference for practical production.