Reaction mechanisms and N-containing compound formation during shoe manufacturing waste pyrolysis

Shoe manufacturing waste (SMW) mainly comprises leather, sponge, cloth, foam, fur, cardboard, hard-woven fabric, and plastic. Pyrolysis is an effective method to valorize SMW by converting them into valuable prod-ucts. However, SMW pyrolysis can cause secondary pollution. The pollutant generation behavior of the indi-vidual SMW components plays a critical role in dictating the overall emission behavior during SMW mixture pyrolysis. In this study, the reaction kinetics and formation of N-containing compounds during the individual SMW components pyrolysis were investigated. Moreover, to better understand the effect of fuel composition on NH3, HCN, and NO emissions, the relationship of the conversion of fuel-N between the nitrogen content as well as the volatile matter and nitrogen weight ratios (VM/N) of the SMW has been explored. The results indicated that when the individual component contained a higher N content, the conversion rates of NO and HCN derived from fuel-N decreased, while the ratio of NH3/HCN in the generated N-containing compounds increased. Investigating the dependence between the fuel composition and the total conversion rates of fuel-N to NH3, HCN, and NO suggests that the VM/N weight ratio of the fuel is a better indicator of the conversion of fuel-N to NH3, HCN, and NO.