Cohydrothermal carbonization of waste polyvinyl chloride and wood chip for dechlorination

¹ Department of Nanoscience, Sojo University, 4-22-1 Ikeda, Nishi-ku, Kumamoto 860-0082, Japan
² Department of Applied Science, Universiti Teknologi of PETRONAS, 32610 Seri Iskandar, Perak Darul Ridzuan, Malaysia
³ Department of Chemical Engineering, Universiti Teknologi of PETRONAS, 32610 Seri Iskandar, Perak Darul Ridzuan, Malaysia

^* Corresponding author: kusakabe@nano.sojo-u.ac.jp

Abstract

The co-hydrothermal carbonization (Co-HTC) of polyvinyl chloride (PVC) film and wood chip (WC) was conducted at 200-260oC in an autoclave filled in air or nitrogen for the chemical recycling of wastes with dechlorination of PVC. Effects of the Co-HTC temperature and the oxidation reaction during the Co-HTC on the decomposition behaviors were investigated. The percentage decomposition in nitrogen atmosphere increased with increasing the reaction temperature and reached 76.1% at 260oC. The percentage decompositions in nitrogen were several percent higher than those in air. The synergistic effect of PVC and WC for the decomposition was observed at 220oC in N₂. When the Co-HTC was performed in air, decomposition was suppressed, indicating the increase in hydrochar yield. The dechlorination yield was determined from the Cl content in the recovered PVC after the Co-HTC reaction. Under nitrogen atmosphere conditions, the dechlorination yield increased slightly with increasing the temperature. At a carbonization temperature of 260oC, the dechlorination yield of PVC was about 40%.