Feasibility study on underground coal gasification of quality characteristics of 9 Chinese coal types

摘要

To study feasibility on underground coal gasification (UCG) of quality characteristics of different coal types, we determined the proximate analysis, total sulfur, ultimate analysis, calorific value, ash composition, ash fusibility, true density, thermal stability and carboxy reactivity of 13 samples from 9 types of different rank Chinese coals (natural coke, anthracite-2, anthracite-3, meager coal, lean coal, coking coal, fat coal, gas coal, lignite), and comparatively analyzed the results. Eight coal properties are selected as key features to judge the UCG feasibility of coal quality and their expected values for UCG are given. Through comparative studies, lignite is the most suitable coal for UCG, with 6 key features meeting the expectations except for the thermal stability (not test) and moisture (without the parameters of groundwater inflow), followed by natural coke, anthracite-2 and lean coal with 4 items satisfying needs, respectively. Contrarily, coking coal is the most unsuitable one for UCG, with 6 key features dissatisfying requirements apart from the ash fusibility and chemical reactivity. Besides that, gas coal, fat coal and anthracite-3 also show poor performance for UCG adaptability, with only 3 key features meeting the demands.