Numerical Simulation Study On Influence Of Arch And Air Distribution Mode For Combustion Performance In Chain Boiler

Coal-fired industrial boilers in China consumes about600million tons of coal, coal accounts for about20%of the total production throughout the year, while the layer burning industrial boiler accounts for about80%of the total coal-fired industrial boiler coal consumption. The vast majority of layer burning industrial boiler is the chain boiler. The decisive principle in the process of chain boiler combustion is3T+E that is time, temperature, turbulence and excess air. The four essential factors are controlled by the arch and the air distribution mode of chain boiler.In order to improve the theory of chain furnace arch and air distribution, In this paper, the combustion process is simplified, for solve the above problem, the numerical simulation study on influence of arch and air distribution mode for combustion performance in chain boiler was carried out by FLUENT software, research the influences of furnace arch and air distribution:The first problem is the furnace arch size effect on the properties of combustion chain boiler:Based on the different front arch heights, different front arch lengths, different rear arch lengths, different rear arch angle were studied by numerical simulation, analysis of the furnace arch size change, the variety of flow field in furnace, front arch temperature, rear arch temperature, heat flux distribution on the grate surface. The results show that reduce the front arch heights, enlarge the front arch lengths is conducive to new fuel ignition; enlarge the rear arch lengths, cut down rear arch angle is not only conducive to the new fuel ignition but also in favor of the new fuel burn out. Comprehensive analysis of furnace arch size effect of chain boiler combustion can be obtained:After the arch length change maximum to the effect of combustion in the furnace, front arch length, rear arch angle change small to the effect of combustion in the furnace, front arch height change minimum to the effect of combustion in the furnace. Through the analysis of furnace arch result size effects on the combustion performance in order to provide the feasibility of the proposed design chain furnace arch.The second problem is the air distribution effect on the properties of combustion chain boiler:Through the study of different air distribution modes influence on fuel ignition front-enhanced is most conducive to grate new fuel ignition, rear-enhanced air supply, strong air supply change small conducive to grate new fuel ignition uniform air supply change minimum conducive to grate new fuel ignition. By mean of the study of different air distribution modes influence on fuel burn out rear-enhanced air supply is most conducive to grate new fuel ignition, strong air supply, rear-enhanced air supply change small conducive to grate new fuel ignition, uniform air supply change minimum conducive to grate new fuel burn out.