Identification of the low-rank coals thermal heating behavior

Abstract

In this study, the object of the research is low-rank coal during the process of thermal heating of five types: brown, high moisture brown, long-flame, coke weakly sintering and coke fusinite. In the research, when conducting thermal and gas analysis in inert media, the problem of using low-rank coal in the thermal heating process to obtain volatile fuel gases was solved by identifying the quantitative and qualitative performance of its behavior. Quantitative indicators are determined as the mass of thermal destruction products: the mass of coal tar and gas products and semi-coke under optimal temperature conditions of their maximum release. Qualitative indicators of coal behavior are components of thermal decomposition products. It is revealed that the behavior of low-rank coals in the process of thermal heating is determined by the degree of metamorphism. In this case, long-flame and brown coals have a lower release of volatile fuel gases than coke weakly sintering and coke fusinite coals due to a lower degree of metamorphism and greater degrees of thermal oxidation and dehydration. Thermal decomposition component ranges consisting of polyaromatic fragments (HCN, C6H12, C4H5N), greenhouse gases (CH4 and CO2), toxic gases (H2S and NH3) and synthesis gases (CO and H2) have the highest share of release. Optimal temperature conditions and ranges for the release of low molecular weight gases used as high calorific volatile fuel gases are obtained. The results can be used in the design, optimization and construction of thermal heating equipment, correction of gasification and pyrolysis processes. Moreover, they can be applied in localized coal tar spots minimization technologies and for designing targeted gases extraction