Co-pyrolysis of low-rank coal and waste truck-tire: A comprehensive study on product distributions, product properties, and synergistic effects

Co-pyrolysis of low-rank coal and waste polymer materials is thought to be a promising way for solid waste disposal and recovering value-added chemicals. In our study, the co-pyrolysis of waste truck-tire (WTT) and Hongliulin low-rank coal (HLL) was carried out in a bench scale fixed-bed reactor to further investigate the synergistic effects during the co-pyrolysis process. The results showed that WTT volatiles inhibited the cross -linking and polycondensation reactions of HLL volatiles to a degree, showing an increase in tar yields. Volatiles -volatiles interactions improved the quality of tar products by enhancing the conversion of heavy components into more light tar, effectively lowering the average molecular weight of tars. The co-pyrolysis produced more chain hydrocarbons and aromatics while producing fewer terpenoids compared with individual pyrolysis, which was attributed mostly to the catalytic effects of char. Volatiles-char interactions increased the graphitization degree and ordered structure of the co-pyrolysis chars, and the pore structure of the co-pyrolysis chars became more developed. The large number of hydrogen-rich radicals produced by WTT pyrolysis consumed the reactive functional groups on the surface of HLL char, resulting in a decrease in the volatiles and cross-linking degree of co-pyrolysis chars. Finally, the potential synergistic mechanism for co-pyrolysis of WTT and HLL was summa-rized and depicted based on the analysis results.

Automated summary

Co-pyrolysis of waste truck-tire (WTT) and Hongliulin low-rank coal (HLL) was carried out to investigate the synergistic effects during the process. The presence of WTT volatiles increased tar yields while improving the quality of tar products. The catalytic effects of char led to the production of more chain hydrocarbons and aromatics. Volatiles-char interactions also enhanced the graphitization degree and pore structure of the co-pyrolysis chars. The synergistic mechanism for the co-pyrolysis of WTT and HLL was summarized based on the analysis results.