THERMOGRAVIMETRIC KINETIC ANALYSIS OF PULVERIZED COAL COMBUSTION IN OXYGEN-ENRICHED CONDITION

摘要

Combustion characteristics of pulverized coal (PC) injected in to Blast furnace under different oxygen concentrations were investigated with thermal analysis device. The influence of oxygen concentration on thermal and kinetic behavior of PC was studied under non-isothermal conditions. Results show that the combustion process could be divided into two steps: the combustion of volatile and the combustion of solid carbon. It is shown in the results that the heating rates and oxygen concentrations have important effects on the main combustion processes of PC. With increase of the heating rate, the initial losing weight temperature and burn out temperature rise, and the amount of residue decreases. With increase of oxygen concentration, the initial losing weight temperature and burn out temperature lower, and the amount of residue decrease, thus the combustion characteristics are improved. Kinetic calculation was carried out for combustion with 21%, 30% and 40% oxygen concentration with Flynn-Wall-Ozawa(FWO) model, which show that activation energy of PC vary from 103.43kJ/mol to 172.40kJ/mol with the increase of oxygen concentration. The average reaction orders of the samples range from 0.91 to 1.05.