Investigation of subbituminous coals by thermogravimetry-mass spectrometry: Part 1. formation of hydrocarbon products

Abstract

The thermal decomposition of a series of subbituminous coals from a Hungarian coal basin was investigated by thermogravimetry-mass spectrometry at a heating rate of 20°C min −1. The mass spectrometric intensities of the aliphatic products (C n H m , n ⩾ 2) and alkyl-substituted aromatic compounds evidenced similar sharp peaks at about 490°C. Methane evolved at higher temperatures in a broader temperature range. Benzene curves were composed of two overlapping peaks and were resolved by least-squares reaction kinetic calculations. The low and high temperature peaks of the benzene curves were near to the peaks of the aliphatic C n H m ( n⩽2) compounds and methane respectively. The amounts of the various products were estimated by the integral of the corresponding mass spectrometric intensities and were correlated with coal rank. The probable sources of the various product compounds were discussed.