Simulation Of Natural Gas Burners With Low NO_x Emission Under Structures And Working Conditions

China’s 14th Five-Year Plan policy calls for green development,optimization of energy structure,improvement of utilization rate of non-fossil energy sources,and efforts to achieve a steady decrease in carbon emissions.As a non-fossil clean energy source,natural gas has the advantages of high combustion efficiency and low sulfur oxide emissions,and the main pollutant is the high temperature combustion,so the study of natural gas burners has an important impact on the sustainable development of China.In this study,a 14MW natural gas burner was tested and validated and numerically simulated:firstly,the furnace chamber temperature and emissions were measured using flue gas analyzers according to the experimental bench,and the accuracy of the numerical simulation was compared,and the numerical simulation was based on SOLIDWORKS to model the burner and furnace chamber in three dimensions,and FLUENT MESHING was used to mesh the model.The model is divided into a grid using FLUENT MESHING,and the Realizable k-εmodel is used to simulate the turbulent flow,the DO radiation model is used to predict the radiative heat inside the furnace,the Eddy Dissipation model(ED)is used to simulate the reaction inside the furnace,and the methane air two-step reaction(WD1)is chosen as the chemical reaction mechanism.The main goal of this project is to reduce the emissions,with the help of the control variable method to change the physical parameters of the burner and operating conditions,extract the velocity field,temperature field,component field of the furnace,compare and analyze the results,by changing the physical parameters of the burner:air deflector,cyclone blade angle,gas pipe angle,the study shows that the installation of air deflector reduces 12.7%NO_xemissions;with the increase of the cyclone blade angle By changing the operating parameters of the burner:excess air coefficient and heat load,the results showed that the NO_xemissions decreased and then increased with the increase of excess air coefficient,and the NO_xemissions were lowest when the excess air coefficient was1.15;with the increase of heat load,the NO_xemissions increased by 52%.With the increase of thermal load,the NO_xemission increases by 52%,and at the thermal load rate of 40%,the emission is 11.5ppm,which reaches the domestic ultra-low emission standard.And based on the response surface analysis(RSM),the quadratic regression equations of four factors,such as the angle of the cyclone blade,the angle of the gas duct,the excess air coefficient,and the heat load rate,and the emissions were obtained,and it was found that within the scope of this study,the degree of influence on the NO_xemissions was in the following order:excess air coefficient>heat load rate>cyclone blade angle>gas duct angle,among them,the interaction between the angle of the cyclone blade and the excess air coefficient,the angle of the excess air coefficient and the gas duct,and the excess air coefficient and the heat load rate has a greater degree of influence on the NO_xemissions.