Zhang Qiang, Li Chenwei, Wu Qiang, Zhang Baoyong
Department of Safety Engineering, Heilongjiang University of Science & Technology Harbin 150022 Heilongjiang China
National Central Laboratory of Hydrocarbon Gas Transportation Pipeline Safety Harbin 150022 Heilongjiang China.
RSC Adv. 2018 Jul 31;8(48):27171-27180. doi: 10.1039/c8ra04820g. eCollection 2018 Jul 30.
Coal mine gas (CMG) is a form of unconventional natural gas and its reserves are abundant. However, a large proportion of coal mine gas cannot be used owing to the low concentration of the extraction gas. The hydrate-based method can be used for the separation and recovery of methane from coal mine gas. To devise an economic and efficient method for the separation of mine gas using hydrates, dry water (DW) was used as the carrier for separation under conditions in which the initial pressure was fixed at 10 MPa and the temperature was set at 274 K. On this basis, repeated gas hydrate separation experiments were carried out three times. A pure-water system, a stirring system, and a system using a compound solution of 1 mol L THF + 500 mg L SDS were used in control experiments. The spectral characteristics of the gas hydrates in pure water were determined by Raman spectroscopy, and the hydration index was calculated. The concentrations of gas components in the equilibrium gas phase were determined by chromatography. Moreover, the hydrate formation rate, methane recovery rate, distribution coefficient and separation factor were also calculated. The results indicate that the average gas hydrate formation rate was up to 6.85 × 10 mol min in the presence of the THF + SDS solution. The maximum average methane recovery rate was 38.15%, the average distribution coefficient was up to 1.99, the average separation factor reached 2.47 and the highest methane concentration in the hydrate phase was 32.2% in DW. In the experimental range, the efficiency of DW in the recovery of methane by gas hydrate separation was greater than that of the stirring system and the system using the THF + SDS compound solution.
煤矿瓦斯（CMG）是一种非常规天然气，其储量丰富。然而，由于抽采瓦斯浓度低，很大一部分煤矿瓦斯无法利用。基于水合物的方法可用于从煤矿瓦斯中分离和回收甲烷。为了设计一种经济高效的利用水合物分离矿井瓦斯的方法，在初始压力固定为10MPa、温度设定为274K的条件下，使用干水（DW）作为分离载体。在此基础上，重复进行了三次气体水合物分离实验。对照实验采用纯水体系、搅拌体系以及使用1mol/L四氢呋喃（THF）+500mg/L十二烷基硫酸钠（SDS）复合溶液的体系。通过拉曼光谱测定纯水体系中气体水合物的光谱特征，并计算水合指数。用色谱法测定平衡气相中气体组分的浓度。此外，还计算了水合物生成速率、甲烷回收率、分配系数和分离因子。结果表明，在THF+SDS溶液存在下，气体水合物的平均生成速率高达6.85×10⁻⁴mol/min。最大平均甲烷回收率为38.15%，平均分配系数高达1.99，平均分离因子达到2.47，干水体系中水合物相中甲烷的最高浓度为32.2%。在实验范围内，干水在通过气体水合物分离回收甲烷方面的效率高于搅拌体系和使用THF+SDS复合溶液的体系。
