Low-temperature co-pyrolysis of a low-rank coal and biomass to prepare smokeless fuel briquettes

Smokeless fuel briquettes have been prepared with low-rank coal and biomass. These raw materials have been mixed in different ratios and have been pyrolysed at 600degreesC with the aim to reduce both the volatile matter and the sulphur content, and to increase the high calorific value (HCV). The co-pyrolysis of coal and biomass has shown a synergetic effect. The biomass favours the release of hydrogen sulphide during the thermal treatment. This fact can be explained in terms of the hydrogen-donor character of the biomass. Moreover, the optimisation of the amount of binder and the influence of different types of biomass in the blend have been studied with respect to the mechanical properties of the briquettes (impact resistance, compression strength and abrasion). Briquettes prepared with sawdust (S) present better mechanical properties than those with olive stones (O) because of its fibrous texture. (C) 2003 Elsevier Science B.V. All rights reserved.