The hydrothermal carbonization (HTC) optimization of oat husk was performed using a response surface methodology. Furthermore, anaerobic digestion (AD) of spent liquor and hydrochar addition were evaluated in the biomethane potential (BMP) test. Results found that temperature influences the most in the studied responses (i.e., mass yield (MY) and higher heating value (HHV)). Optimal hydrochar MY (53.8%) and HHV (21.5 MJ/kg) were obtained for 219.2 °C, 30 min, and 0.08 of biomass/water ratio. A successful prediction capability of the optimization approach was observed, archiving an error < 1% between predicted and validated responses. The BMP experiment showed the feasibility of spent liquor as a potential substrate to be treated by AD (144 NmLCH₄/gCOD). Hydrochar boosted the methane production of spent liquor increasing up to 17% compared to digestion with no hydrochar addition. These findings provide new insights regarding oat husk valorization by integrating HTC and AD for energy production.

使用响应面方法对燕麦壳进行水热碳化 (HTC) 优化。此外，在生物甲烷潜力 (BMP) 测试中评估了废液的厌氧消化 (AD) 和加氢炭。结果发现温度对所研究的响应影响最大（即质量产率 (MY) 和较高的热值 (HHV)）。在 219.2 °C、30 分钟和 0.08 的生物质/水比率下获得了最佳的水炭 MY (53.8%) 和 HHV (21.5 MJ/kg)。观察到优化方法的成功预测能力，在预测和验证响应之间存档误差 < 1%。BMP 实验表明废液作为潜在底物被 AD (144 NmLCH ₄/gCOD）。与不添加 Hydrochar 的消化相比，Hydrochar 将废液的甲烷产量提高了 17%。这些发现通过整合 HTC 和 AD 用于能源生产，提供了有关燕麦壳价值的新见解。