Strengthening the results of destroying the caking property of CBC in weak oxygen and upgrading pyrolysis products

摘要

This paper is aimed to characterize the pyrolysis reaction characteristics of caking bituminous coal after being pre-oxidized to break the caking property in a fixed bed reactor. The effects of different preoxidation temperature, carrier gas flow and oxygen volume fraction on the destruction of the caking property were investigated. The distribution of the pyrolysis products, tar composition and gasification reaction reactivity were analyzed using the selected instruments and calculated by mathematic models. The experimental results showed that the weight loss of the raw coal (ZC) and the demineralized coal (ZC-D) increased gradually, with that of ZC-D always higher than that of ZC under same experimental conditions. When the caking index of ZC decreased from 90.05 to 57.88, the heavy tar content decreased from 53.79% to 42.51%, while the light tar content increased from 46.21% to 57.49%, which indicates that the pre-oxidation effectively reduced its caking property and accelerated the release of the volatile matter from coal particles. After pre-oxidation, the specific surface area, average pore diameter and total pore volume of char increased, which improved the gasification reactivity of char as the destruction of caking property had been enhanced. (C) 2017 Elsevier Ltd. All rights reserved.