Study On Combustion Characteristics And Engineering Application Of Low Volatile Blended Coals

The coal-burning boilers are usually designed according to the specific coal, when the coal is different, the furnace designed structure and burning device are different too. But in fact, more and more power plants are very difficult to insist on continuing using the designed coal. In order to save the cost and maintain original operational efficiency at the same time, coal blending combustion become the choice of power plant. However,many thermal power exist various problems when combusting coal blends, because of the lack of suficient understanding of them. Therefore, it has impotrant practical engineering value and academic research meaning to lucubrate the using of coal blends.Running experience indicates that blending single coal which have signification difference in grindibility will bring signification difference in single coal under the same mill system. And it will affect combustion. This paper regarding it as a guiding theory, had carried on systematic theory analysis and experimental study on coal analysis and combustion character of coal blends.Thermogravimetric analysis experiment on the single coal, coal blends and coal blends indicate, because of the segergation of particle size of coal blends, their ignition mainly lie on the single coal with low ignition temperature or high grindability. While, their burning through performance can be determined by the single coal with harder burning through performance or low grindability .The grind ability of single coal and blended coals mixed was measured by the Hardgrove Grindability Index HGI. It was found that grindability was non-additive especially when coals of significant different HGI were blended. The single coal represent different particle size distribution in coal blends. The particle size of the single coal with high grindability, the single coal with low grindability on the contrary. Also the fuzzing mathematics method was used to calculate optimum mixture ratio.On the base of above results, a mill system concept of blending combustion by dividing grind was brought forward. Boiler combustion experiment on coal blends prepared by different methods was taken. The results indicated that the coal blends which were blended after grinded have better burning performance, because the low quality single coal's ignition and combustion condition has improved. Reliabilitysaty and economical efficiency is abtianed.The blended coals methods can be applied in the similar power plant.