Physiochemical, structural and combustion properties of hydrochar obtained by hydrothermal carbonization of waste polyvinyl chloride

Abstract In this study, hydrothermal carbonization (HTC) was used to convert waste polyvinyl chloride to produce hydrochar by evaluating its physiochemical, structural and combustion properties for use as a solid fuel. The results showed that the yield, H/C and O/C atomic ratio of hydrochars decreased with the increase of HTC temperature, meanwhile the higher heating value increased. From physiochemical property analysis, hydrochars had more abundant pore structure and higher ordering degree of carbonaceous due to elimination, aromatization and polymerization reaction during HTC process. The combustion and kinetic analysis results show that the hydrochar obtained at the HTC temperature of 250 °C and time of 60 min had the best combustion reactivity. The activation energy calculated by KAS and OFW methods were similar, and the average activation energy of hydrochars calculated by KAS method ranged from 124.8 kJ/mol to 234.7 kJ/mol.