Co-combustion behavior of municipal solid waste and food waste anaerobic digestates: Combustion performance, kinetics, optimization, and gaseous products

Abstract

Abstract With the rapid development of food waste anaerobic digestion, the safe treatment of its digestates (FWD) is an urgent mission. Co-combustion of FWD with municipal solid waste (MSW) provided a cleaner and sustainable solution. In this study, the co-combustion behavior of FWD and MSW was investigated by thermogravimetric and Fourier transform infrared (TG-FTIR) analysis. Co-combustion with MSW improved the combustion performance of FWD. Compared to calculative value, experimental CCI were maximally improved at M9F1, with growth of 32.9%. Besides, the combustion indexes were exponentially enhanced as the heating rate increased. CCI of MSW and FWD increased by 7.97 times and 7.33 times as heating rate rose from 10\xa0K/min to 40\xa0K/min. Kinetic analysis showed that the average apparent energy for FWD and MSW were 141.3 and 159.1\xa0kJ/mol, respectively. The lowest average apparent energy was obtained at M1F9 with 135.5\xa0kJ/mol. According to the established model, optimal operating condition was achieved at 540.4\xa0°C, 40\xa0K/min and MSW proportion of 0.95. FTIR results showed that total gas emissions of CO2, CO, NO, HCN and HCl from MSW were greater than FWD. High proportion of FWD was beneficial to reduce the emissions of gaseous pollutants. The experimental emissions of NO and HCl were decreased by 20.8% (M3F7) and 18.6% (M7F3).