Experimental Research on the Burning of Anthracite Mixed with Lean Coal and Its NOx Emission Characteristics

By using a thermobalance and a small sized pulverized coal combustion test rig an experimental study was conducted for a multitude of test items. The latter include the combustion characteristics of anthracite, lean coal and the blends of the above two coals in three different proportions, NOx generation mechanism at different combustion air supply rates, and burn out characteristics. Through the processing and analysis of the test data it is concluded that there exists some differente in combustion performance between the anthracite and lean coal with the performance of the blends of these two coals exhibiting intermediate characteristics. A proper selection of excess air factor can lead to a high efficiency combustion of anthracite and lean coal blended in different ratios and to low NOx emissions. With respect to coals being blended in three different ratios a suitable range of excess air factor values is proposed to attain a high efficiency combustion and low pollutant emissions. This may serve as a guide for the cost effective and clean operation of power plants firing the above coal blends.