Harmful emission in boiler-houses of average capacity using wood for fuel

Abstract

About 25 % of firewood is used in boiler-houses of average capacity and there is a clear increasing tendency of this. Despite the fact that biomass burning is neutral in terms of CO2 emissions the reduction of environmental pollution is rather relevant. First of all we speak about solid particles emission. It is not feasible to ensure the requirements of environmental norms without using filtration installations. The level of emission before filters exceeds 600 mg/m3. The concentration of pollutants in combustion gases very highly depends on the characteristics of biomass and the boiler operation mode. As the carried out trials showed the emissions of volatile materials can differ several times for the same boiler. A reasonable proportion of pollution is made of nitrogen oxides. If the biomass used is of low quality, their concentration can exceed the permissible threshold rate of 750 mg/m3. The emission of carbon monoxide for two types of boilers exceeded or was close to the permissible rate of 4000 mg/m3. The total pollution level in burning biomass was much lower compared with coal.