Combustion process in a biomass fuel bed --experimental results

Paper in proceeding, 2001

Combustion processes in a biomass bed are investigated experimentally. Special attention is paid to the influence of primary air flow and particle properties on the ignition front, its temperature and on the composition of the gas leaving the front. Two test rigs have been built: a large rig in the same size as a domestic boiler and a small laboratory test rig. In both rigs the combustion front moves in opposite direction to the primary air flow. Two combustion regimes are identified: a sub-stoichiometric regime with complete consumption of oxygen and an over-stoichiometric regime. The results show that a fuel with higher density and thermal conductivity (but in other respects similar) has a wider sub-stoichiometric regime. If the particle size is increased the air flow range becomes shorter and starts at higher air flow.