Comparison of the formation characteristics of condensable particulate matter from the combustion of three solid fuels

Abstract

Exploring the formation characteristics of condensable particulate matter (CPM) and guiding its directional regulation are beneficial. Therefore, coal, pine, and sewage sludge fuels were combusted, and the differences in the contents and compositions of the generated CPM were analyzed. The results show that the CPM concentrations generated by the combustion of the three fuels are different. Maximum total CPM concentration (19.79 mg/m3) was generated by sewage sludge. The CPM concentrations generated by coal and pine were 14.1 mg/m3 and 7.57 mg/m3, respectively. The SO42− content generated by combusting sewage sludge was considerably higher than that by coal, and the SO42− content generated by the pine was the lowest. The high nitrogen content in sewage sludge influenced the SO42− content, and the oxides in the filterable particulate matter affected the formation of SO3. The NH4+ content in the CPM generated by the sewage sludge was the highest among the three fuels and is more related to the nitrogen content in fuels. The differences in the compositions and properties of the fuels lead to the differences in the CPM generated. Hydrocarbons accounted for the largest proportion of the organic fractions of CPM generated by the three solid fuels. The emission concentration of CPM can be reduced by removing N, S, and Cl from the fuel and adjusting the combustion atmosphere. This study lays the foundation for understanding the formation mechanisms of CPM.