Formation characteristics of volatile organic compounds during co-heating of municipal sewage sludge and municipal solid waste incineration fly ash

Co-heating of municipal sewage sludge (MS) and municipal solid waste incineration fly ash (FA) can effectively reduce the formation concentration of volatile organic compounds (VOCs) in solid waste, reducing environmental pollution while achieving solid waste reduction. The effects of co-heating temperature and blending ratio on the formation characteristics of VOCs during the co-heating of MS and FA were investigated through experiments and numerical simulation. Co-heating experiments were conducted using a horizontal tube furnace equipped with a Tenax-TA VOCs adsorption tube. The co-heating was conducted with different FA:MS ratios at 1100 degrees C to select the optimal blending ratio. The effects of co-heating temperature on VOCs formation characteristics were investigated at the optimal blending ratio. Chemkin software was used to simulate the migration and transformation paths of typical VOCs. The results indicated that the addition of FA inhibited the formation of VOCs. At 1100 degrees C, an FA:MS ratio of 3:7 was identified as optimal, significantly reducing the VOCs formation concentrations by 98.9 % compared to the theoretical values of VOCs. At this blend ratio, VOCs formation concentrations decreased from 1877.1 ng/L to 240.5 ng/L as the co-heating temperature rose from 800 to 1100 degrees C. However, a slight increase in VOCs formation concentrations was observed at 1200 degrees C. Simulation results revealed nine elementary reactions governing benzene transformation, with C3H3 identified as a crucial precursor for benzene formation. This study provides a scientific foundation for assessing solid waste compatibility and co-heating temperature to inhibit VOCs formation during municipal solid waste's industrial synergistic thermal disposal process.