Flue Gas Emissions on the Oxygen-Enriched Combustion of Brown Coal and Woody Biomass

Abstract

The use of waste woody biomass as a renewable fuel is increasingly pronounced due to the necessary decarbonization of the energy sector in accordance with the acquired scientific knowledge about the characteristics of co-firing of this biomass with other primary fuels in specific temperature and other technical-technological settings. With the aim of expanding the existing knowledge and especially obtaining new knowledge, research was carried out in laboratory conditions on the co-firing of a mixture of brown coal and waste woody biomass in a pulverized state, in the conditions of an oxygen-enriched atmosphere - research into the possibility of applying new combustion technologies from the field of oxy fuel combustion for different solid fuels. The main purpose of the subject research was, through the performance of a set of laboratory test regimes, to determine the influence of changes in the content of oxygen in the oxidant on the composition and emission of flue gases. In this regard, during different test regimes, the composition of flue gases was analyzed, and the emission level of CO2, CO, NOx and SO2 was determined. In addition to changing the composition of the oxidant in the combustion furnace (O2 ≥ 21%), the test regimes were also performed at different process temperatures (950 ÷ 1250) °C and for different mixtures of the subject fuels with (0 ÷ 20)% biomass proportion in the mixture. The obtained results are presented in this paper. It is evident from this that the increase in the proportion of oxygen in the oxidant has a significant impact on the change in the composition of flue gases compared to the composition during combustion with air. As a key result of the research, it was established that the fuels in question can be used without hindrance in the treated conditions of the oxy fuel combustion technology: the efficiency of the conversion of primary energy from the fuel is very high, and at the same time, the extraction of CO2 from the resulting flue gases in their possible further treatment is significantly facilitated (CCS - Carbon capture and storage).