Co-pyrolysis of industrial hemp stems and waste plastics into biochar-based briquette: Product characteristics and reaction mechanisms

Industrial hemp stems and polyvinyl chloride are heat-treated at 400-800 C to prepare cylindrical biochar-based briquette. The results show that the co-pyrolysis of industrial hemp stems and Polyvinyl chloride degrade at 205-519 C with a mass loss of 84.173 wt%. According to the TG-FTIR, the co-pyrolysis of industrial hemp stems and polyvinyl chloride produces large amounts of volatiles such as CH4, CO, CO2 and HCl. With the increase of pyrolysis temperature and holding time, industrial hemp stems can produce biochar-based briquette with a lower O/C-H/C ratio. Polyvinyl chloride can significantly improve the durability of biochar-based briquette. Besides, polyvinyl chloride can significantly increase the high heating value of biochar-based briquette due to the HCl gas increases the fixed carbon content of biochar-based briquette in the preparation process. When industrial hemp stems and polyvinyl chloride at the ratio of 1:1, the maximum high heating value of biochar-based briquette can reach 29.475 MJ/kg. The concentration of Cl in biochar briquettes is 9.260 mg/g, mainly in the form of metal chloride. Therefore, biochar-based briquette has a potential application prospect in bioenergy production due to the remarkable improvement of its properties.

Automated summary

Industrial hemp stems and polyvinyl chloride can be heat-treated to produce cylindrical biochar-based briquette. The co-pyrolysis of these two materials results in a significant mass loss and produces large amounts of volatiles. The addition of polyvinyl chloride improves the durability and high heating value of the biochar-based briquette. This study suggests that biochar-based briquette has potential applications in bioenergy production.