Synergistic effect during co-pyrolysis of tea seed shell and waste printed circuit board: Thermogravimetric characteristics and operation parameter optimization

To convert tea seed shell (TSS) into bio-energy, the co-pyrolysis behaviors of TSS and waste printed circuit boards (WPCB) were studied. The impacts of synergy during co-pyrolysis were ascertained by analyzing the thermogravimetric characteristics and product properties. Blends with varying ratios of TSS and WPCB were studied using TGA for thermal decomposition analysis and a fixed-bed reactor for product analysis. According to thermal behavior analysis, the results revealed a synergistic effect when WPCB and TSS were co-pyrolysis. The dynamics of the co-pyrolysis process was confirmed using Coats–Redfern (C–R) method and the Arrhenius method. For WPCB, the values of Ea using the C–R method with the reaction orders of 1 and 1.5 were about 310.08 and 370.91 kJ/mol, respectively, while for the mixture containing 80% TSS, those values were reduced to 59.80 and 73.48 kJ/mol, respectively. To optimize the operation process, the effects of operated factors, e.g. mixing ratio, on the yields and properties of the products were fully investigated in a fixed-bed reactor. The presence of synergistic effects was further confirmed, but different results were observed for the experiments from TGA and the fixed-bed reactor. Under the optimized condition, the yields of gas, liquid, and solid products were 48.71%, 34.79%, and 16.5%, respectively.