We conducted the removal of hydrocarbons and concentrating of H₂ from the tail gas of diesel hydrogenation (tail gas for short) using hydrate separation method. Based on the preliminary separation results, it is necessary to apply hydrate thermodynamic promoter to further improve the separation efficiency. In order to avoid the introduction of new impurity, we added propane (C₃H₈), one component of tail gas, in the feed gas as the hydrate promoter by reverse thinking, because it runs counter to the hydrocarbons removal from tail gas. The formation equilibrium conditions of tail gas hydrates were measured, and the enthalpy of hydrates equilibrium dissociation was calculated by the Clausius–Clapeyron equation. The results show that the addition of C₃H₈ significantly decreases the formation equilibrium pressure of tail gas hydrates at the same temperature. It indicates that C₃H₈ indeed performs as a thermodynamic promoter for tail gas hydrates. Consequently, the driving force for hydrates formation increases, and more hydrates form at the equilibrium state. As a result, the total removal rate of hydrocarbons and the recovery rate of H₂ are both increased, while the concentration of H₂ in equilibrium gas almost keeps unchanged. The results demonstrate that the addition of C₃H₈ behaves as an inducer to enclose relatively more hydrocarbons into hydrate phase, and it also accelerates the hydrates formation rate at the same time. This work presents a new research idea, i.e., cast a small fish for a big one, for the flexible and optimum application of hydrate separation technology.

我们使用水合物分离法从柴油机加氢的尾气（简称尾气）中去除了碳氢化合物并浓缩了H ₂。根据初步分离结果，有必要使用水合物热力学促进剂以进一步提高分离效率。为了避免引入新的杂质，我们通过逆向思考在进料气中添加了作为尾气成分的丙烷（C ₃ H ₈）作为水合物促进剂，因为它与去除尾气中的烃类相反。测量了尾气水合物的形成平衡条件，并通过Clausius–Clapeyron方程计算了水合物平衡解离的焓。结果表明，C的加成₃ H ₈在相同温度下显着降低了尾气水合物的形成平衡压力。这表明C ₃ H ₈确实充当了尾气水合物的热力学促进剂。因此，形成水合物的驱动力增加，并且在平衡状态下形成更多的水合物。结果，增加了烃的总去除率和H ₂的回收率，而平衡气体中的H ₂浓度几乎保持不变。结果表明，添加了C ₃ H ₈起到诱导剂的作用，将相对更多的烃封入水合物相中，同时也加快了水合物的生成速度。这项工作提出了一种新的研究思路，即将一条小鱼变成一条大鱼，以灵活，最佳地应用水合物分离技术。