Abstract:

Hydrate-based solidified natural gas (SNG) technology provides a promising method for natural gas storage, but high-pressure production environment makes it difficult to separate and store the formed hydrate, causing difficulty in achieving continuous hydrate production. In order to promote its application, it is of significant importance to enhance the formation kinetics of hydrate, while hydrate efficient production, separation and storage are also anticipated. In this work, a novel spiral-agitated hydrate formation setup was proposed, and the integrated hydrate formation, separation and storage was fulfilled. Two nano promoters of $—\mathrm{S}{\mathrm{O}}_{\mathrm{3}}^{-}$@PSNS and —COO^-@PSNS were prepared via emulsion polymerization method, which enhance hydrate later formation kinetics, giving rise to hydrate efficient production. It was found that hydration efficiency under a mild condition of (5 MPa, 275.15 K, 30 r/min) was significantly enhanced by the synergictic effect of nano promters and spiral agitation, in the two nano promoter systems of $—\mathrm{S}{\mathrm{O}}_{\mathrm{3}}^{-}$@PSNS and —COO^-@PSNS, hydrate induction time is only 1.59 and 6.48 min respectively, while gas storage capacity in hydrate is up to 128.38 m³/m³. Compared with —COO^-@PSNS, $—\mathrm{S}{\mathrm{O}}_{\mathrm{3}}^{-}$@PSNS performs better on enhancing hydration efficiency. In addition, low energy consumption was required in the spiral-agitated hydrate formation setup, it takes 3.69×10^-2 and 6.81×10^-2 kW·h to form and separate 1 kg hydrate, and compared with —COO^-@PSNS, the energy consumption in $—\mathrm{S}{\mathrm{O}}_{\mathrm{3}}^{-}$@PSNS system can be saved by 45.81%. This study makes it possible to efficiently and continuously prepare hydrates, providing theoretical guidance for the application of solid natural gas technology in the field of natural gas storage.

Key words: hydrate, solidified natural gas, natural gas storage, spiral agitation, nano promoters

摘要：

基于水合物的固体天然气（solidified natural gas， SNG）技术为天然气储存提供了一种新型、高效途径，但水合物的高压生成环境限制了其分离与储存，进而制约了水合物的连续制备，而强化水合物的生长动力学，实现水合物高效生成、分离与储存是该技术应用的关键。提出了一种新型螺旋搅拌反应装置，实现了水合物生成、分离与储存一体化，并通过乳液聚合法制备了$—\mathrm{S}{\mathrm{O}}_{\mathrm{3}}^{-}$@PSNS与—COO^-@PSNS两种纳米促进剂，强化了后期水合物生长动力学，进而实现了水合物高效制备。研究表明，在较温和条件下（5 MPa，275.15 K，30 r/min），纳米促进剂与螺旋搅拌协同作用大幅强化了水合效率，在$—\mathrm{S}{\mathrm{O}}_{\mathrm{3}}^{-}$@PSNS与—COO^-@PSNS体系，水合物诱导时间分别为1.59和6.48 min，水合物储气量高达128.38 m³/m³，且与—COO^-@PSNS相比，$—\mathrm{S}{\mathrm{O}}_{\mathrm{3}}^{-}$@PSNS对水合效率的强化更突出。利用螺旋搅拌反应装置制备水合物仅需较低能耗，在$—\mathrm{S}{\mathrm{O}}_{\mathrm{3}}^{-}$@PSNS和—COO^-@PSNS体系中，生成和分离1 kg水合物所需能耗分别为3.69×10^-2和6.81×10^-2 kW·h，且$—\mathrm{S}{\mathrm{O}}_{\mathrm{3}}^{-}$@PSNS体系比—COO^-@PSNS体系节能45.81%。研究结果使得水合物高效、连续制备成为可能，为固体天然气技术在天然气储存领域的应用提供了理论指导。

关键词: 水合物, 固体天然气, 天然气储存, 螺旋搅拌, 纳米促进剂