This investigation examines the co-combustion behavior and pollutant emission patterns of coal blended with two biomass types-rice husk (RH) and Populus tomentosa sawdust (SD)-at varying mixing ratios. Utilizing thermogravimetric analysis (TGA) and a drop-tube furnace system, the combustion performance and emission characteristics were systematically evaluated. The results show that co-firing with RH or SD can effectively improve the combustion performance of coal, and both coupled combustion mechanisms conform to the diffusion model. By comparing the theoretical and experimental values of thermogravimetric curves, it is found that in the main combustion range of 400°C~570°C, the interaction between coal and RH/SD first inhibits combustion and then promotes combustion, with the transition occurring around 500°C. The low sulfur content in RH and SD is the main factor for reducing SO₂ emissions. However, there is a significant difference in their nitrogen content, while their NOx emission reduction capabilities are not significantly different-with a difference of only 1.89 % when the blending ratio is 25+%. This indicates that co-firing biomass with high nitrogen content can still effectively reduce NOx emissions. For this reason, a possible NOx emission reduction mechanism is proposed.
Gu et al. (Thu,) studied this question.