Thermal decomposition of solid oxygenated complexes formed by coal oxidation at low temperatures

Solid oxygenated complexes formed by coal oxidation play an important role in low-temperature oxidation of coal. Using an isothermal-flow reactor, the decomposition behaviour of solid oxygenated complexes was examined under pure nitrogen, at temperatures between 60 and 110 degreesC. The production of CO2 and CO during thermal decomposition of the complexes was quantified by an on-line dual-column micro GC. Experiments show that the production rates Of CO2 and CO depend on temperature, but are independent of the particle size of the samples, indicating that the thermal decomposition process is dominated by chemical kinetics rather than diffusion. It was also found that the rates of formation of carbon oxides follow the Elovich equation and the activation energies for the production Of CO2 and CO are 52.1 +/- 6.3 and 72.0 +/- 5.8 kJ/mol, respectively, indicating two separate reaction pathways proceeding in the decomposition of solid oxygenated complexes. (C) 2002 Elsevier Science Ltd. All rights reserved.