Effects of remained catalysts and enriched coal minerals on devolatilization of residual chars from coal liquefaction

Devolatilization behaviour of residual chars from coal liquefaction was investigated using thermogravimetric analysis. Effect of remained and enriched minerals on devolatilization of residual chars was mainly concerned. By analysing TG/DTG profiles, it was found that the measured volatile matter (VM) includes not only the decomposed volatile products of unreacted organic substances of coal but also that of the inorganic materials. such as enriched mineral matters, remained liquefaction catalyst, as well as by-products formed in catalyst preparation. Therefore, the VM measured by the standard proximate analysis (up to 950degreesC) should preferably be called 'total volatile matter' (TVM), which does not reflect the organic properties of the residue as one would expect for VM, Therefore, the VM released from 110 to 700degreesC was named organic VM, which shows a better linear relationship with WC ratios of the residual char and characterises the reactivity of the residue more rationally than TVM does. (C) 2002 Elsevier Science Ltd. All rights reserved.