STUDY ON THE COMBUSTION CHARACTERISTICS AND KINETICS OF PULVERIZED COAL IN HIGH OXYGEN-ENRICHED CONDITION

摘要

The combustion characteristics of bituminous coal and anthracite under oxygen enriched condition were researched by thermogravimetric analysis. The DTG curve of bituminous coal had one peak, whereas for anthracite the curve changed from one peak to two peaks with volume fraction of oxygen increased. With volume fraction of oxygen increased: the thermogravimetric curve moved towards low temperature zone; the ignition temperature and burn out temperature decreased; the largest weight loss rate and average weight loss rate increased and the burn out time was shortened. When volume fraction of oxygen was lower than 40%, the combustion characteristics of coal were improved significantly, and when over than 40%, the effects were not that significant, so the optimum volume fraction of oxygen in oxygen enriched blast of a blast furnace should be kept between 30-40%. The combustion process of pulverized coal with oxygen enriched condition was analyzed by Coats-Redfern integration method: with increase of volume fraction of oxygen, the activation energy of pulverized coal combustion was increased; there existed obviously compensation effect during combustion process, and the compensation formula was also given.