NUMERICAL INVESTIGATION OF FUEL CHARACTERISTICS AND CONCENTRATION ON PULVERIZED COAL COMBUSTION

A three-dimensional numerical simulation of the flow, combustion, heat transfer and NOx formation process is applied to a 1MW pulverized coal furnace with two swirl burners oppositely installed at the front and back walls. Different cases as varying the coal properties, coal concentration bias and air supply are simulated in detail. Comparisons of simulation and experimental temperature distributions are conducted and the results show that the numerical and experimental results are consistent generally. Air supply has obviously influence on combustion characteristics and the ratio of inner and outer secondary air is a key factor for air staged combustion. The fuel rich/lean combustion can significantly reduce the NOx emission, however the injcetion position for the fuel rich stream must match the recirculation zone.