Numerical And Experimental Study On The Novel Blunt-body Burner And Low NOx Combustion Reconstruture Used In Power Plant Boilers

Along with the lack of high-quality coal, more and more power plants in china used the poor-grade and even worse coal with low volatile and high ash to generate electrical-power. It results in a lot of problems including the instability of the combustion performance of boilers and the extremely high emission of pollutants beyond the national standard.To solve the first problem, we developed a novel blunt-body burner with a crisscross shape that was improved from traditional kinds of blunt-body burners. The aerodynamic field round the nozzle of this novel blunt-body burner was numerically studied using the commercial code Fluent, which was based on the principles of computational fluid dynamics. Also, the aerodynamic field round the nozzle of a traditional blunt-boby burner without design improvement was simulated simultaneously. And the results of them were compared. The comparison demonstrates clearly that the novel blunt-body burner is able to produce more steady combustion performance than the traditional one because of the design of it that can bring on the larger refluence field, more intense disturbance in this field and larger reflux round the nozzle of the burner. In terms of the configuration of burners, it demonstrates that after the reconstruction the carbon content of ash is 4.64% when using the coal with low quantity of heat of 12 470 J/g, volatile content 22.08%, and the carbon content of slag of 5.82%. They are all less than 6%. It is noted that the design of novel blunt-body burner has achieved the goal for steading the combustion status and improving the efficiency of burner.In addition, to solve the second problem, we proposed an application that based on the coal reburning technique combined with gas recycling technique. This combination can present both advantages of these two techniques for deducing the NO_x emission up to an extremely low level. We also investigated the inner temperature distribution of a...