The co-combustion and pollutant emission characteristics of lignite and lake sediment

Abstract

Lake sediment is a high moisture solid waste that carries a large amount of water pollutants, significantly impacting the environment and urban landscape. The efficient management of lake sediment has emerged as a critical challenge requiring immediate attention. This paper focuses on the characteristics of co-combustion and its pollutant emissions. The combustion characteristics of mixed combustion of lake sediment and coal in different proportions were obtained by the thermogravimetric method. Experiments elucidated the influence of diverse factors on the variability of NO and SO₂ concentrations. The remaining bottom residue of the reaction and the reasons for the changes in emission concentration are analysed from a microscopic perspective. Results indicate that the appropriate proportion (<20 %) of mixed lake sediment promotes coal combustion. NO and SO₂ decrease with increased bed temperature, lake sediment mixing ratio (5 %–15 %), and particle size. As the bed temperature increases, the particle surface melts, reducing the pore structure and reaction sites, thereby reducing the generation of pollutants. When the mixing ratio exceeds 15 %, NO increases while SO₂ decreases. Calcium based substances have little catalytic effect on NO, but are still effective for SO₂. Larger particles will promote the decomposition of NO on their surface.