An increasing amount of spent coffee grounds (SCG) has resulted in a huge burden on landfills; thus, alternative viable technologies are needed. The hydrothermal carbonization of SCG was studied to determine to produce high-quality hydrochar. The influence of three independent variables (temperature, reaction duration, and solid to liquid ratio) on the yield of hydrochar and conversion was investigated through 15 experimental runs using central composite design (CCD). The most optimized conversion and hydrochar yield results were 89.8 % and 10.1 %, respectively. Higher heating value (HHV) progressed considerably from 19.1 MJ/kg of SCG to 21.2 MJ/kg of hydrochar. The ultimate analysis results for hydrochar revealed that the quantity of carbon (C) upgraded from 50.1 to 55.9 %, whereas; oxygen (O) content decreased from 40.5 to 38.7 %, hence improving the energy and combustion properties. The Scanning electron microscopy (SEM) analysis portrayed the alteration in the structure of SCG and improved porosity after hydrothermal processing, which was further investigated via Brunauer-Emmett-Teller (BET) analysis. BET surface area improved from 4.4 m²/g (for SCG) to 16.5 m²/g (for hydrochar). The thermal stability of hydrochar was upgraded from 330 °C for SCG to 375 °C for hydrochar.

越来越多的废咖啡渣（SCG）给垃圾填埋场带来了巨大的负担；因此，需要替代可行的技术。研究了SCG的水热碳化，以确定生产高质量的水炭。使用中心复合设计 (CCD) 通过 15 次实验运行研究了三个自变量（温度、反应持续时间和固液比）对水炭产率和转化率的影响。最优化的转化率和水炭收率结果分别为 89.8% 和 10.1%。较高的热值 (HHV) 从 19.1 MJ/kg SCG 显着提高到 21.2 MJ/kg 水炭。水炭的最终分析结果表明，碳 (C) 的数量从 50.1% 提升到 55.9%，而；氧 (O) 含量从 40.5 % 降至 38.7 %，从而提高能量和燃烧性能。扫描电子显微镜 (SEM) 分析描绘了 SCG 结构的变化和水热处理后孔隙率的改善，通过 Brunauer-Emmett-Teller (BET) 分析进一步研究了这一点。BET 表面积从 4.4 m 提高² /g（用于 SCG）至 16.5 m ² /g（用于水炭）。水炭的热稳定性从 SCG 的 330 °C 升级到水炭的 375 °C。