Abstract Our previous work reported to simultaneously remove the alkali and alkaline earth metals, and chlorine by co-hydrothermal carbonization (co-HTC) of high-alkali coal and polyvinyl chloride (PVC) (Fuel Process Technol, 199(2020)106277). This work is to investigate on the moisture re-adsorption characteristics of those hydrochar obtained at various co-HTC operating conditions. The results show that the water re-adsorption capacity of hydrochar was decreased with the circumstance temperature rising from 20 °C to 35 °C, while it was increased with the air humidity increasing from 50% to 80%. During the co-HTC, the addition of PVC could effectively inhibit the moisture re-adsorption behavior of hydrochar resulting from the adhere of the hydrophobic PVC to the surface of hydrochar as evidenced by SEM. The circumstance temperature had a significant influence on the effective diffusivity D over the humidity. The equilibrium moisture content (EMC) and effective diffusivity (D) could be linearly correlated with surface area and most probable pore size, respectively. The EMC of hydrochar was reduced about 0.6 mg/g as the BET surface area decreased 1 m2. The reduction of oxygen-containing groups could reduce the adsorption equilibrium time and adsorption heat. Besides, the higher circumstance humidity would cause hydrochar to release higher adsorption heat. As the humidity was increased from 70% to 80%, the heat released by 1 g hydrochar was increased about 13.82–19.63 kJ/mol. Due to the lower EMC and adsorption heat, 300 °C was supposed to be a suitable temperature for the co-HTC to obtain hydrophobic hydrochar.

中文翻译：

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PVC与碱煤共水热炭化水热炭的吸湿特性

摘要 我们之前的工作报道了通过高碱煤和聚氯乙烯 (PVC) 的共水热碳化 (co-HTC) 同时去除碱金属和碱土金属以及氯 (Fuel Process Technol, 199(2020)106277)。这项工作是为了研究在不同 co-HTC 操作条件下获得的那些氢化物的水分再吸附特性。结果表明，随着环境温度从20°C升高到35°C，水炭的吸水能力降低，而随着空气湿度从50%升高到80%，它的吸水能力增加。在共 HTC 过程中，通过 SEM 证明，PVC 的添加可以有效地抑制疏水性 PVC 粘附在 Hydrochar 表面导致的 Hydrochar 的水分再吸附行为。环境温度对相对于湿度的有效扩散率 D 有显着影响。平衡水分含量 (EMC) 和有效扩散率 (D) 可以分别与表面积和最可能的孔径呈线性相关。随着 BET 表面积减少 1 m2，氢化碳的 EMC 降低了约 0.6 mg/g。含氧基团的减少可以减少吸附平衡时间和吸附热。此外，较高的环境湿度会导致水焦释放较高的吸附热。随着湿度从 70% 增加到 80%，1 g 水焦释放的热量增加了约 13.82–19.63 kJ/mol。由于较低的 EMC 和吸附热，300 °C 被认为是 co-HTC 获得疏水性水炭的合适温度。