Dechlorination of cellulose and polyvinyl chloride by torrefaction and characterization of product escape

Abstract

Abstract Cellulose, which is the main constituent of both PVC and biomass, was chosen for investigation in this study. The process of torrefaction was employed to eliminate the elemental chlorine in PVC. Firstly, the co-pyrolysis process of cellulose and PVC was analyzed using thermogravimetric analysis to determine the effect of different ratios and identify an appropriate torrefaction temperature. torrefaction experiments were then conducted on cellulose and PVC with various mixing ratios to assess the removal rate of chlorine in the co-mixed compounds. Additionally, the pyrolysis products of cellulose and PVC were analyzed using thermogravimetric-infrared coupling technique. The experiment demonstrated that when mixing cellulose with PVC in a ratio of 9:1, the blend experienced weight loss at temperatures ranging from 279.65-404.72°C. Moreover, the total weight loss was 94.32%, while chlorine removal reached 99.18% following torrefaction at a temperature of 300°C for 90 minutes. At 340°C during PVC pyrolysis, the HCl absorption degree was 0.1213. In the case of co-pyrolysis, the HCl absorption degree of the two co-pyrolysates was only 0.0037 at 322°C. This indicates that the combined pyrolysis of the two components would result in the early escape of HCl, while reducing the amount of HCl escaping.