School of City and Architecture Engineering, Zaozhuang University, Zaozhuang 277160, China E-mail:
Water Sci Technol. 2020 Dec;82(12):3017-3022. doi: 10.2166/wst.2020.546.
Hydrothermal carbonization is a feasible way to convert biomass into valuable hydrochar, the recycle of spent liquor during HTC is beneficial to reduce the output of spent liquor. The effects of spent liquor recycle on the properties of hydrochar and the biogas potential of spent liquor are investigated in this study. Part of the spent liquor (50% volume fraction) was recycled four times at 220 and 240 °C HTC, respectively. The results showed that the surface area of hydrochar was in the range of 7.2-8.6 m/g after spent liquor recycle, and the peak of -OH, C = O and C-O became more intense. The Cd adsorption capacity of hydrochar was around 1.3 mg/g and it decreased by 0.02-0.15 mg/g after spent liquor recycle. The biogas yield of spent liquor kept declining from 263 to 29 mL/g-COD with each cycle of spent liquor. Our results suggest that spent liquor recycle is a promising method to improve hydrothermal carbonization process.
水热碳化是将生物质转化为有价值的水炭的一种可行方法，在 HTC 过程中回收废水中的液体有利于减少废水量的排放。本研究考察了废水中液体的回收对水炭性质和废水中生物气潜力的影响。部分废水中液体（50%体积分数）在 220 和 240°C 的 HTC 条件下分别循环回收四次。结果表明，经过废水循环回收后，水炭的比表面积在 7.2-8.6 m2/g 范围内，-OH、C=O 和 C-O 的峰值变得更强。水炭对 Cd 的吸附容量约为 1.3 mg/g，经过废水循环回收后，其吸附容量降低了 0.02-0.15 mg/g。随着废水循环次数的增加，废水中的沼气产量从 263 下降到 29 mL/g-COD。我们的结果表明，废水循环回收是一种有前途的改进水热碳化工艺的方法。
