Prediction of the Combustion Behavior of Blended Coals in Coal Blending for Power

摘要

The quality parameters of the blended coals, such as ash content, calorific value, sulfur content,moisture content, volatile matter, and so on, are identical with that of the single coal, but thecombustion behavior of the blended coals may be very different from that of the single coal. Inorder to nicely forecast the combustion behavior of blended coals, it is very necessary for us tofind the method to predict combustion behavior of blended coals in coal blending for power inChina.This paper studies the relations between ‘burning profile curve’ DTG of coals of different typesor ranks and their quality parameters by means of thermal gravimetric analysis. The results showthat DTG of single coal displays a peak and the relation between the peak temperature (Tmax ) ofDTG of single coal and the logarithm of its fuel ratio index F (the ratio of fixed carbon to volatilematter) is linear namely :Tmax =68.86Ln F +512.°CTherefore, DTG of the blended coals can be derived according to F of its component coals incoal blending. Then, the combustion behavior of the blended coals can be predicted according tothe rule that if DTG of coals are the same, their combustion behaviors are alike. The practicalcombustion of blended coals in the small test boiler is performed, which prove that the method topredict the combustion behavior of blended coals is correct.