Research Progress of Hydrothermal Carbonization Technology

Hydrothermal carbonization（HTC）can significantly improve hydrophilicity of waste with high moisture content, improve hydrophobicity of solid products, and facilitate purification of subsequent products．Due to its advantages such as simple treatment method, short reaction time, low energy consumption, and continuous treatment, as well as its ability to obtain water carbon with high carbon content, abundant active oxygen-containing functional groups on the surface, large specific surface area, and developed porosity, it is an emerging waste resource utilization, reduction, and harmless treatment method．Method and principle of hydrothermal carbonization was introduced, mechanism of reaction process was clarified, physical and chemical properties and characteristics of solid products obtained from hydrothermal carbonization by some scholars in recent years were summarized, and relationship between two indicators O/C, H/C, and reaction intensity that affect thermal stability of water carbon was discovered．Two important process parameters（reaction temperature and residence time）were optimized to meet degree of carbonization while saving resources．Important position of hydrothermal carbonization in thermochemical conversion has been established．Impact mechanism of raw material composition, temperature, time, liquid-solid ratio, and catalyst addition on hydrothermal synthesis was systematically analyzed, and challenges and development opportunities faced by hydrothermal carbonization technology in high humidity waste treatment were prospected, providing reference for promoting efficient utilization of organic waste and reducing environmental hazards of waste．