高压工况下气液聚结过滤微观作用机理研究

In the natural gas storage and transportation process, such as gas injection process in gas storage, micron-sized droplet impurities are often entrained by high-pressure natural gas. The droplets were difficult to efficiently separated by conventional gas-liquid coalescence filtration method, which endangers the production safety seriously. To break through the technical bottleneck, it is urgent to understand the microscopic mechanism of coalescence filtration under high-pressure condition. The applicant's previous research found that when the operating pressure is increased, the filter material appears structural deformation and the liquid saturation rises, resulting in degradation of macroscopic filtration performance. We deduce that the internal cause is that the particle diffusion effect is weakened under high pressure condition, which lead to the coalescence efficiency reduced. Meanwhile, the droplet migration is hindered by the increased gas density and the deformed physical structure of the filter material. This project intends to establish a high-pressure gas coalescence filtration performance test system, to experimentally study the physical properties of the coalescing filter materials and their filtration properties under different gas densities and pressure levels. The UV curing, Micro-CT and filtration process simulation will be used, to reveal the influence mechanism of the physical properties of coalescing filter materials, droplet coalescence and migration under high-pressure. Furthermore, a theoretical model of filtration efficiency and pressure drop will be established which comprehensively reflects the trend of gas-liquid filtration performance at different pressure. The research results will provide a theoretical basis for the development of high-efficiency gas-liquid filtration technology for high-pressure natural gas storage and transportation.

在储气库注气等天然气储运工艺过程，高压天然气中常夹带有微米级液滴杂质，常规气液聚结过滤方法难以对其高效分离，严重危害生产安全。亟需通过深刻理解高压工况下气液聚结过滤的微观作用机理，突破高压天然气气液聚结过滤的技术瓶颈。申请人前期研究发现，操作压力升高时，过滤材料存在结构变形、液体饱和度升高，导致宏观过滤性能退化。因此推测高压工况下颗粒扩散效应减弱降低聚结效率，气体密度增大和滤材物性改变阻碍了液滴运移。本项目拟通过建立高压气体聚结过滤性能测试系统，研究不同气体密度和压力等级下聚结过滤材料的物性及其过滤性能的变化规律；利用紫外光固化和Micro-CT等实验手段以及过滤过程模拟，揭示操作压力对聚结过滤材料物性、液滴聚结及运移的影响机制，建立综合反映不同压力等级下气液过滤性能变化趋势的过滤效率和压降理论模型。研究成果将为研发适用于高压天然气储运领域的高效气液过滤技术提供理论依据。

在高压天然气储运过程中，对于粒径2微米以下液滴的分离，气液聚结过滤是目前唯一可行的技术。相比于气固两相过滤，气液聚结过滤过程存在气体、液滴在多孔纤维介质内的复杂流动和相互作用，过滤性能受到更多参数的影响，亟需深刻认识高压工况下气液聚结微观过滤机理。在本基金项目的支持下，建立了高压气体聚结过滤性能测试平台，结合实验室测试、现场试验和理论分析开展研究工作。综合运用过滤材料物性分析手段开展了微观机理研究，阐明了压力工况对聚结过滤材料宏观性能的影响机制。系统探索不同压力等级下过滤元件内部区域的气体流动、液滴分布形态和液滴沉降特性，揭示了疏油改性和仿生纤维对复合滤材过滤性能的提升机理。建立了反映高压工况下的过滤性能变化趋势和运行寿命预测的无量纲准数及理论模型。基于本项目研发的天然气过滤用聚结滤芯及高压气体管道内液滴检测装备，帮助解决了以海上天然气平台为代表的高压天然气净化用高效聚结过滤元件设计与运行优化问题。