(173ai) Co-Hydrothermal Carbonization of Biodegradable Straw Waste and Rice Husk

Hydrothermal carbonization (HTC) is an environmentally friendly thermochemical process used to convert wet biomass into a solid carbon-rich product. Recently, there has been growing interest in co-hydrothermal carbonization (Co-HTC), which involves using two or more types of solid waste simultaneously. This approach is gaining attention as an efficient means of waste disposal. In this study, biodegradable straw waste (PLA) and rice husk (RH) were employed for co-hydrothermal carbonization. The investigation aimed to assess the impact of Co-HTC between biodegradable straw waste and rice husk at different ratios, reaction times, and temperatures on product distribution and hydrochar properties. The findings revealed several significant trends: 1) PLA/RH ratio: Increasing the RH content in the mixed feedstocks resulted in higher solid yields but lower oil yields. Additionally, the elevated RH content in the mixed feedstocks was proposed to promote the conversion of organic matter into hydrochar, leading to increased thermal stability and higher heating value (HHV) of hydrochar. 2) Reaction time: Prolonging the reaction time led to an increase in solid and gas yields, while the oil yield decreased. The longer reaction time enhanced cracking and recombination/repolymerization of molecules, resulting in higher volatile matter content in hydrochar and increased HHV. 3) Temperature: Higher reaction temperatures led to the maximum solid yield and HHV of hydrochar, achieved at 260°C. Overall, the study provides valuable insights into optimizing Co-HTC processes for efficient waste utilization and hydrochar production.