LOW-EMISSION COMBUSTION IN A FLUIDISED BED REACTOR

Regardless of the type of fuel and organization of the combustion process, usage of air as an oxidizer in this process is a source of nitrogen oxides emission. Significant increase in the emission occurs when fuel is itself a source of nitrogen. The nitrogen oxides formed in combustion processes, conducted in industrial processes, in power industry as well as in households pose a serious threat to the environment and human health when released to the atmosphere. Apart from solid fossil fuels, solid biomass is being increasingly used for energy purposes. However, it does contain significant amounts of nitrogen, usually exceeding the amount of nitrogen found in coal, in the form of organic bases and amino acids. Combustion of biomass, on the one hand, could lead to significant reduction in the growth of CO2 emission into the atmosphere, however; on the other hand it could become a significant factor in the increase in global emission of nitrogen oxides. Use of techniques and technologies that protect the atmosphere from an inflow of additional stream of nitrogen oxides would, therefore, seem inevitable. Besides methods involving chemical reduction of NOx in flue gases in isolation from the area where is the source of flue gases, methods for reducing amount of nitrogen oxides in the exhaust fumes carried in the combustion zone, are also known and applied. This paper presents results of experimental studies in which two-zone combustion in bubble fluidised bed reactor was applied in aim to reduce of NO concentration in flue gases