The Effect of Coal Particle Size on Pyrolysis Equilibrium.pdfVIP

** BACK TO INDEX The Effect of Coal Particle Size on Pyrolysis Equilibrium Xue Yongqiang* Yan Ruiping and Ding Yihui Department of Coal Processing and Utilization, Shanxi Institute of Mining and Technology, Taiyuan, Shanxi, 030024, P.R.China Abstract: The granularity of pulverized coal has some effect on its pyrolysis. The relation of pyrolysis equlibrium constant between block coal and pulverized coal was derived, and the effects of granularity, surface tension and density on the pyrolysis equilibium was discussed in this paper. The results show that the pyrolysis equilibrium constant increases with a decrease in the coal particle size and the density or an increase in the surface tension. Key words: pulverized coal, particle size, pyrolysis, equilibrium constant, volatile substances. 1. Introduction Pyrolysis is involved in gasification, coking, liquefaction and combustion of coal. In these processes, pyrolysis plays an important role. Not only does coal types, heating speed, temperature and pressure act on pyrolysis of pulverized coal, but the particle size acts on that as well. The volatility of the small size particles is greater than that of the big ones[1-2] , and so is the conversion ratio of the hydrogenation pyrolysis[3]. Elliott[4] considered that it was because the bigger the particle size, the greater the opposition to escaping the volatile gases. We think that this explaination is not all-sided because the surface effect is not taken into consideration. As the particle size of