Experimental study on the partial preheating combustion characteristic of Yankuang coal sludge

摘要

Abstract Coal sludge is a seriously polluted solid waste, and the rational utilization of its resources has long being an undoubtedly important research topic. This paper mainly studies the coal sludge partial preheating characteristic, combustion characteristic and the process of migration and conversion of nitrogen with preheating combustion technology. The experimental results indicate that most of the elements in the coal sludge are released during preheating, and the ratio of the fuel-N converted to the N2, NH3 and HCN are 75.5%, 6.74% and 0.64%, respectively. Compared with the coal sludge, the BET surface area and cumulative pore area of preheated char are increased. The surface of preheated char is loose and porous with many fine particles, while raw coal is dense with larger particles. Meantime, the quantity of carbon defect structure, the active sites and the reactivity of preheated char are all increased. In the whole process, the NOx emission is about 156?mg/m3 (@6% O2), the ratio of fuel-N converted to NOx was 2.98%, and the combustion efficiency is 96.5%. This experiment results will play a vital role in efficient and clean utilization of coal sludge.