Co-hydrothermal carbonization of biomass and PVC for clean blast furnace injection fuel production: Experiment and DFT calculation

In this paper, a co-hydrothermal carbonization (co-HTC) process of biomass and polyvinyl chloride (PVC) is proposed. The feasibility of applying the product to blast furnace injection was verified, and the effects of different temperatures, liquid–solid ratios and holding times on the characteristics of the co-HTC products of pine and PVC were studied. After co-HTC, the fixed carbon and HHV increased to varying degrees, while the H/C and O/C atomic ratios decreased. Compared with single HTC, co-HTC significantly improved the removal efficiency of the alkali metals and organic chlorine up to 94.46% and 95.61%, respectively. Moreover, a physicochemical characteristic analysis was performed, and it showed that the order degree of the hydrochar carbonaceous structure increased and that C[dbnd]O and C[dbnd]C decreased and increased, respectively. Moreover, the physicochemical characteristic analysis showed that the corresponding combustion characteristics deteriorated. The density functional theory calculation showed that in HTC, the elimination order of the Cl atoms at the four sites followed 2-1-3-4. Moreover, the substitution was found to be more likely to occur in the region of sites 3–4.