Structural Effects of Gas Hydrate Antiagglomerant Molecules on Interfacial Interparticle Force Interactions
Structural Effects of Gas Hydrate Antiagglomerant Molecules on Interfacial Interparticle Force Interactions
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DOI：
10.1021/acs.langmuir.0c02503
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发表时间：
2021-01-28
期刊：
影响因子：
3.9
通讯作者：
Koh, Carolyn A.
中科院分区：
文献类型：
--
作者：
Hu, Sijia;Vo, Loan;Koh, Carolyn A.
天然气水合物颗粒间黏结力对于确定水合物晶体颗粒团聚行为和随后的水合物浆液输送至关重要，这对于防止海底油气管道堵塞的潜在灾难性后果至关重要。采用一种独特的高压微机械力装置，研究了工业相关水合物抗团聚剂（AA）抑制剂的分子结构对天然气水合物晶体颗粒间相互作用的影响。四种具有已知详细结构的AA分子[具有两条长尾（R1）和一条短尾（R2）的季铵盐]，其中R1具有12个碳（C12）和8个碳（C8）以及饱和（C-C）与不饱和（C=C）键，在本工作中研究了它们的界面活性，以抑制两种液态烃（正十二烷和正庚烷）存在下的水合物晶体颗粒间相互作用。所有的原子吸收剂都能从基线（23.5 +/- 2.5 mN m(-1)）降低颗粒间的黏结力，但AA-C12在两种液态烃中表现出比其他原子吸收剂更好的性能。界面测量结果表明，长R1烷基链的AA能提供更致密的屏障，当R1烷基链尾长与液态烃链尾长相当时，AA分子在水合物晶体表面具有更高的堆积密度。增加盐度可以提高AA分子的有效性，也可以消除颗粒接触时间延长的影响，这通常会增加颗粒间的凝聚力。本研究首次在工业相关条件下对已知高性能分子结构的原子吸收剂进行了实验研究，结果表明，这些分子可以降低界面张力，增加天然气水合物-水接触角，从而最大限度地减少天然气水合物颗粒间的相互作用。本研究报告的结构-性能关系可用于帮助设计改进的AA抑制剂分子，这将是工业水合物晶体浆输送的关键。
Gas hydrate interparticle cohesive forces are important to determine the hydrate crystal particle agglomeration behavior and subsequent hydrate slurry transport that is critical to preventing potentially catastrophic consequences of subsea oil/gas pipeline blockages. A unique high-pressure micromechanical force apparatus has been employed to investigate the effect of the molecular structure of industrially relevant hydrate antiagglomerant (AA) inhibitors on gas hydrate crystal interparticle interactions. Four AA molecules with known detailed structures [quaternary ammonium salts with two long tails (R1) and one short tail (R2)] in which the R1 has 12 carbon (C12) and 8 carbon (C8) and saturated (C-C) versus unsaturated (C=C) bonding are used in this work to investigate their interfacial activity to suppress hydrate crystal interparticle interactions in the presence of two liquid hydrocarbons (n-dodecane and n-heptane). All AAs were able to reduce the interparticle cohesive force from the baseline (23.5 +/- 2.5 mN m(-1)), but AA-C12 shows superior performance in both liquid hydrocarbons compared to the other AAs. The interfacial measurements indicate that the AA with an R1 longer alkyl chain length can provide a denser barrier, and the AA molecules may have higher packing density when the AA R1 alkyl tail length is comparable to that of the liquid hydrocarbon chain on the gas hydrate crystal surface. Increasing the salinity can promote the effectiveness of an AA molecule and can also eliminate the effect of longer partide contact times, which typically increases the interparticle cohesive force. This work reports the first experimental investigation of high-performance known molecular structure AAs under industrially relevant conditions, showing that these molecules can reduce the interfacial tension and increase the gas hydrate-water contact angle, thereby minimizing the gas hydrate interparticle interactions. The structure-performance relation reported in this work can be used to help in the design of improved AA inhibitor molecules that will be critical to industrial hydrate crystal slurry transport.