低剂量吸水树脂稳定活性微滴水合储甲烷动力学

Kinetics of hydrated methane storage in microdroplets stablized by low dosage of absorbent polymer

水合物的快速循环生成是水合物技术应用的关键。将十二烷基硫酸钠溶液与疏水性气相纳米二氧化硅和低剂量(质量分数0.1%~1.0%)吸水树脂置于搅拌器中快速搅拌,得到吸水树脂稳定的表面活性剂溶液微滴,其本质是由高分子聚合物改性的活性干溶液。在8.0 MPa和274.2K下,利用该活性微滴以水合物的形式存储甲烷,研究甲烷水合物在微滴中的生成动力学特性。研究表明,分散的聚合物改性微滴能为气体传输提供众多纵横交错的通路,从而极大增加了气液间接触面积,且每个微滴均具有稳定的胶质结构和活性表面。该聚合物稳定的表面活性液滴能促进甲烷水合物迅速形成,储气量高达152.5~173.3 cm^(3)·g^(-1),储气速率也达到7.62~19.70 cm^(3)·(g·min)-1。聚合物质量分数为0.1%的微滴气体存储容量最大,第7次循环前的储气量均在170 cm^(3)·g^(-1)以上,第12次循环储气量仅比第1次循环储气量衰减了14.7%。该成果对于大规模应用水合物快速循环储运天然气技术具有借鉴作用。

The circulation of rapid hydrate formation is critical to the utilization of hydrate technology.The super absorbent polymer-stabilized surfactant microdroplets(SAP-DS)were prepared by mixing low dosage(0.1%~1.0%)of super absorbent polymer,sodium dodecyl sulfate(SDS)solution,and hydrophobic silica nanoparticles in air at high speed,which was essentially a cluster of active dry solution modified by polymer.At 8.0 MPa and 274.2 K,these surfactant microdroplets were used for methane storage as hydrates.And the formation kinetics of methane hydrates in microdroplets were studied.Results indicate that the loose polymer-modified microdroplets can provide numerous crisscrossing channels for gas transfer,which greatly increases the surface area for gas-droplet contact.Each droplet has a stable gel structure and surface activity.Microdroplets stabilized by polymers can promote the rapid formation of methane hydrate.Their gas storage capacity can reach as high as 152.5~173.3 cm^(3)·g^(−1),and the gas storage rate reaches up to 7.62~19.70 cm^(3)·(g·min)^(−1).The highest gas storage capacity is achieved by the microdroplets with a mass fraction of 0.1%polymer.The SAP-DS can maintain relatively high methane uptake of 170 cm^(3)·g^(−1) before the seventh cycle,while the uptake in the twelfth cycle is only attenuated by 14.7%compared to the first cycle.The findings can provide a reference for the large-scale rapid circulated storage and transportation of natural gas in the form of hydrates.