Emission of pollutants from a biomass stove

Abstract It is important to know the mechanisms by which biomass combustion in a stove emits pollutants in order that appropriate remedial steps may be taken to protect the environment in general and to safeguard the health requirements of stove users who are predominantly in the Third World. In this paper, the levels of concentration of emissions have been investigated by use of a GC analyzer for CO and UHC, a chemiluminescent analyzer for NO x and a smoke detector for smoke density. The emissions can be categorised into two main groups: unburnt pollutants (CO, UHC, smoke) and oxidized pollutants (NO x , CO 2 ). The former can be avoided by creating conditions in the stove conducive for complete combustion, while the same cannot apply to NO x emission, since its source is the fuel bound nitrogen. Emission factors obtained for CO, CH 4 and NO x were: 17.56, 0.89 and 0.173 kg/ton, respectively, during charcoal combustion and 11.3, 0.46 and 0.19 kg/ton, respectively, during wood combustion. Fuel nitrogen was converted to NO and NO 2 with an overall conversion efficiency of 27.1 and 33.2% during charcoal and wood combustion, respectively. Because of the high emission of carbon monoxide, biomass stoves should be used where there is adequate ventilation. The smoke density of 80% during wood combustion, which was twice as high as that measured during charcoal combustion, renders wood fuel unsuitable for use in a stove.