Abstract:

Rapid formation of hydrate with high gas storage capacity is vital for the application of gas hydrates technology. In this paper, water, hydrophobic fumed nano-silica and low-dose [0.1%—1.0%(mass)] superabsorbent resin were mixed and dispersed at a high speed in a mixer to prepare a superabsorbent resin-modified dry water. The modified dry water is essentially a free-flowing swarm of scattered microdroplets held together by polymers with high molecular weight. The scattered microdroplets were employed for methane hydration and storage at 8.0 MPa and 274.2 K, and the kinetics of methane hydrate formation was investigated. The results indicate that the loose polymer droplets significantly increase the specific surface area of the liquid-phase continuous water, hence providing many pathways for gas diffusion to the surface of the droplet. Methane hydration is rapidly created in this droplet. The gas storage rate may reach 5.15—8.78 cm³·g^-1·min^-1, and the gas storage capacity is as high as 158.0—175.0 cm³·g^-1. The microdroplets with a mass fraction of 0.3% showed the fastest storage rate and the highest gas storage capacity, and the gas storage capacity of the first six times in the process of circulating hydration gas storage exceeded 120 cm³·g^-1. The findings have significant implications for the large-scale use of hydrate storage and transportation natural gas technology.

Key words: methane hydrate, superabsorbent resin, dispersed droplets, formation kinetics, promotion

摘要：

高储气密度水合物的快速生成对气体水合物技术应用至关重要。将水与疏水性气相纳米二氧化硅和低剂量［0.1%~1.0%（质量）］的超吸水树脂在搅拌器中高速混合分散，制备出一种超吸水树脂改性的干水。该改性干水实质上是由高分子聚合物支撑且可自由流动的分散微滴堆。在8.0 MPa和274.2 K条件下，研究该改性微滴中甲烷水合物生成动力学特性。结果表明，松散的聚合物微滴极大地改善了液相连续水比表面积，为气体扩散至微滴表面提供了丰富的通道。水合物在聚合物微滴中快速生成，储气速率可达5.15~8.78 cm³·g^-1·min^-1，储气量高达158.0~175.0 cm³·g^-1。质量分数为0.3%的微滴表现出最快储存速率和最高储气量，且其循环水合储气过程中前6次储气量均超过120 cm³·g^-1。研究结果对水合物储运天然气技术规模化应用有一定的参考价值。

关键词: 甲烷水合物, 超吸水树脂, 分散微滴, 生成动力学, 促进