Performance Optimization And Engineering Application Study On Low Nitrogen Burner For Biogas Boiler

As a kind of renewable and clean energy,biogas has the advantages of wide source of raw materials,high calorific value,and low environmental pollution.These advantages make it the substitute to provide fuel for boilers and so on.Boiler occupies a large proportion of energy consumption in China,as boiler fuel,biogas can alleviate the problem of energy shortage and environmental pollution.But except for a large number of CH₄,biogas also contains some CO₂ and a small amount of H₂S gas,which makes its combustion characteristic different from conventional fuel.At present,there are only a few researches on the combustion of biogas,and the researches on the application of low nitrogen burner for biogas boiler can be negligible.Based on combustion system supply of a biochemical company's biogas boiler,this paper researches the combustion of biogas burner and the burners'performance optimization.Firstly,this paper introduces the general situation of biogas boiler.With the combination of staged combustion technology and swirling jetting technology,the technical scheme of the burner is determined based on the design parameters of the boiler.The main work includes the relevant combustion calculation,the design of matching process and control system.Secondly,by using the method of numerical simulation,the performance of the burner was optimized from the aspects of the two key factors of the excess air ratio?and the swirl angle?by FLUENT software.When?is 1.0,1.05,1.1 and1.15,?is 40°,50°and 60°,the combustion sitution in the boiler is simulated.Compared with the differences of velocity fields,temperature fields and NO_X content in the boiler under different working conditions,burner's best parameters is determined when?is 1.1 and?is 50°.By comparing the simulation results before and after optimization,it is found that the average temperature in the furnace is reduced by about50K and the local high temperature zone is also reduced.Besides,the temperature distribution is more uniform and the NO average mole fraction content is decreased by about 1.1×10^-5.At last,the thermal test of the optimized burner was carried out.Compared with the simulation results,it is found that the coincidence of the two is better.In the design load50t/h,NO emissions of the boiler is only 56mg/Nm³,which is well below the national requirements of 100mg/Nm³.The research can provide some reference and guidance for the performance optimization and engineering application of biogas burner in the future.