Management of university solid waste in China through gasification technology: An analysis of waste composition and energy potential

This study explored the composition and energy potential of university solid waste (USW) in China. Five combustible components, namely hard plastics (HP), paper (PP), soft plastics (SP), biomass (BM), and rubber (RB), were screened with the compositions 51%, 29%, 9%, 4%, and 3%, respectively. Each USW sample was gasified using a thermogravimetric analyzer (TGA) coupled with mass spectrometry (MS) at the heating rates of 5, 10, and 15 ℃/min and a final process temperature of 900 ℃. Thermal weight loss (TG) curves exposed the degradation in the order HP > SP > RB > BM > PP. Derivative thermogravimetric (DTG) peaks revealed that HP, PP, BM, and SP were degraded in three temperature-oriented phases in the range 172–731 ℃. The RB took an additional phase in the range 584–660 ℃. Major released gases, H2, CH4, CO, and CO2, were detected using MS via mass-to-charge (m/z) ratios. Higher H2 and total gas yield produced in the case of the HP dominated other materials at the lower heating rate of 5 ℃/min. Validation of data was assessed by equating experimental and calculated curves; therefore, the regression coefficient (R2) ranged between 0.884 and 0.997. The kinetics of the process were estimated by applying the Flynn–Wall–Ozawa (FWO) model at the conversion rates (α) of 0.2, 0.5, and 0.8, which presented reasonable results. Overall, the lower heating rates supported higher thermal conversion and a high quantity of gaseous products for all the components.