CHARACTERIZATION OF THE FUEL BED COMBUSTION OF WOOD RESIDUES IN A 4 MW GRATE BOILER

摘要

Information about distributions of temperature and gas species within the fuel bed is of greatrnimportance in studying the formation of pollutants in an industrial-scale biomass boiler. The main objective of thisrnstudy was to investigate the gas composition and temperature in some available sections of the fuel bed of a 4 MWrnreciprocating grate boiler, burning mixture of fresh pine wood chips, bark, and sawdust with two significantlyrndifferent moisture content levels. The averageCO, CO_2,CH_4, and O_2 concentrations measured during the combustionrnof the more moist fuel (about 60 mass %) were about 12, 12, 2, and 4 vol. %, respectively, whereas the correspondingrnvalues for the less moist fuel (about 45 mass %) were about15, 10, 2.5, and 5 vol. %, respectively. Higherrnconcentration of CO and lower concentration of CO_2 for the less moist fuel could originate either from the charrnconversion process or from the reactions of the devolatilizationgas products.