Combustion Simulation And Conceptual Design Of A Flameless Oxidation Burner

The flameless oxidation was discovered in 1989 during trials aimed at NO-reduction in combustion with highly preheated air.The flameless oxidation can be defined as:stable combustion without flame with a defined recirculation rate of hot combustion products.After nearly 40 years of research,mature technologies of flameless oxidation had been formed,and flameless oxidation burners had also been industrialized in European and America.The research on flameless oxidation in China is later than that in other countries.Mature industrial flameless oxidation burners have not been developed in China either.The flameless oxidation burner has many advantages than the conventional burner,such as:uniform combustion temperature,large temperature radiation range,low pollutant emission,high efficiency,energy saving,and low noise.Summing up the experience of predecessors and considering actual conditions,we selected suitable reaction mechanism models for diffusion flameless oxidation combustion in the study,such as the following.1?Basic equations:energy conservation equation,momentum conservation equation,mass conservation equation and component conservation equation.2?Turbulence model:Standard k-?model in RANS.3?Radiation model:P-1 model.4?Component transport and reaction flow model:ED model in finite-rate models.5?Contaminant generation models:thermal NO_x and prompt NO_x formation models.The CFD simulation tool of Fluent is employed in the current study to simulate a 15kW burner.The influence of four factors,i.e.,the number of air nozzle,the gas injection velocity,the angle of air injection and the location of outlet,on the combustion performance was studied.An optimum configuration was obtained:1?The number of air nozzles is 6.2?The air injects into the furnace in parallel with the gas injection.3?The flue outlet is in the lower part.In a collaborative research project between South China University of Technology and Sichuan Ally High-tech Corporation,a 10Nm³/h natural gas steam reforming device has been developed to produce hydrogen.A diffusive flameless oxidation burner with a rated heat load of 15kW was designed for the heat generation in the H₂ production unit.The burner has many advantages,such as simple structure,high efficiency,energy saving,invisible flames,uniform temperature distribution and low NO_x emission.