Fang Bin, Ning Fulong, Hu Sijia, Guo Dongdong, Ou Wenjia, Wang Cunfang, Wen Jiang, Sun Jiaxin, Liu Zhichao, Koh Carolyn A
National Center for International Research on Deep Earth Drilling and Resource Development, Faculty of Engineering, China University of Geosciences Wuhan Hubei 430074 China
Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology Qingdao 266237 China.
RSC Adv. 2020 Aug 24;10(52):31027-31038. doi: 10.1039/d0ra04088f. eCollection 2020 Aug 21.
Anti-agglomerants (AAs), both natural and commercial, are currently being considered for gas hydrate risk management of petroleum pipelines in offshore operations. However, the molecular mechanisms of the interaction between the AAs and gas hydrate surfaces and the prevention of hydrate agglomeration remain critical and complex questions that need to be addressed to advance this technology. Here, we use molecular dynamics (MD) simulations to investigate the effect of model surfactant molecules (polynuclear aromatic carboxylic acids) on the agglomeration behaviour of gas hydrate particles and disruption of the capillary liquid bridge between hydrate particles. The results show that the anti-agglomeration pathway can be divided into two processes: the spontaneous adsorption effect of surfactant molecules onto the hydrate surface and the weakening effect of the intensity of the liquid bridge between attracted hydrate particles. The MD simulation results also indicate that the anti-agglomeration effectiveness of surfactants is determined by the intrinsic nature of their molecular functional groups. Additionally, we find that surfactant molecules can affect hydrate growth, which decreases hydrate particle size and correspondingly lower the risk of hydrate agglomeration. This study provides molecular-level insights into the anti-agglomeration mechanism of surfactant molecules, which can aid in the ultimate application of natural or commercial AAs with optimal anti-agglomeration properties.
目前，天然和商业用的抗聚剂都被用于海上作业中石油管道的天然气水合物风险管理。然而，抗聚剂与天然气水合物表面之间相互作用的分子机制以及水合物团聚的预防仍然是关键且复杂的问题，需要解决这些问题以推动这项技术的发展。在此，我们使用分子动力学（MD）模拟来研究模型表面活性剂分子（多核芳香羧酸）对天然气水合物颗粒团聚行为以及水合物颗粒间毛细管液桥破坏的影响。结果表明，抗团聚途径可分为两个过程：表面活性剂分子在水合物表面的自发吸附作用以及被吸引的水合物颗粒间液桥强度的减弱作用。MD模拟结果还表明，表面活性剂的抗团聚效果取决于其分子官能团的固有性质。此外，我们发现表面活性剂分子会影响水合物生长，这会减小水合物颗粒尺寸，相应降低水合物团聚的风险。本研究为表面活性剂分子的抗团聚机制提供了分子层面的见解，这有助于具有最佳抗团聚性能的天然或商业抗聚剂的最终应用。
