Anti-Agglomeration Effects of Biodegradable Surfactants from Natural Sources on Natural Gas Hydrate Formation

Abstract

Kinetic hydrate inhibitors (KHI) and anti-agglomerants (AA) rather than thermodynamic hydrate inhibitors (THI) are often used for flow assurance in pipelines. This is because they require much lower dosages than thermodynamic inhibitors. Although the hydrate-phase equilibria are not affected, KHI and AA prevent the formed hydrate crystals from growing to a bulky state causing pipeline blockage. However, these KHIs might have huge environmental impact due to leakages from the pipelines. In this study, two biodegradable AA candidates from natural sources (that is, lecithin and lanolin) are proposed and their performances are evaluated by comparing them with and without a conventional AA (Span 80, sorbitan monooleate). At 30% and 50% water cut, the addition of AA materials was found to enhance the flow characteristics substantially in pipelines and hardly affected the maximum value of the rotational torque, respectively. Considering the cost-effective and environmental advantages of the suggested AA candidates over a conventional AA such as Span 80, the materials are thought to have potential viability for practical operation of oil and gas pipelines. However, additional investigations will be done to clarify the optimum amounts and the action mechanisms of the suggested AAs.

Screening Hydrate Antiagglomerants for an Oil–Gas–Water System from Various Commercial Chemicals Using Rocking Cells

“…As a biodegradable zwitterionic surfactant from natural sources, lecithin has been reported as an effective hydrate AA. 21 However, lecithin was ranked as a class C AA in this work. This indicates that the screening criteria and apparatus may affect the performance and classification of AAs.…”

“…The polymers adopted in this work are mainly the drilling-fluid additives, which are expected to be screened as potential effective hydrate AAs for the drilling process. Because the antiagglomerating results may be apparatus-dependent, some chemicals with good hydrate-antiagglomerating performance in the literature were evaluated as a reference in this work, including the AA-8 (didodecyl dimethylammonium chloride , ), AA-30 (lecithin), AA-31 (cocamidopropyl dimethylamine − ), and AA-32 (rhamnolipid).…”

“…Recently, some natural zwitterionic surfactants such as lecithin were also found to have a hydrate-antiagglomeration effect. 21 For the nonionic surfactants, Huo et al 8 found that sorbitan surfactants of 3 wt % such as Span can keep the hydrate particles well-suspended in the system at 277.15 K and 8.27 MPa, while the synthesized dodecyl-2-(2-caprolactamyl)ethanamide was more efficient at a lower effective concentration of 0.75 wt %. Kelland et al 9 studied the performance of alkylamide surfactants, and some of the adopted surfactants exhibited good performance as hydrate dispersants.…”

“…The results showed that the prevention of hydrate plugging can be achieved by using amine oxides, and the performance of hydrate AAs can be affected by multiple factors including the head/spacer groups of AAs, the subcoolings, and the compositions of hydrocarbon liquids. Recently, some natural zwitterionic surfactants such as lecithin were also found to have a hydrate-antiagglomeration effect . For the nonionic surfactants, Huo et al found that sorbitan surfactants of 3 wt % such as Span can keep the hydrate particles well-suspended in the system at 277.15 K and 8.27 MPa, while the synthesized dodecyl-2-(2-caprolactamyl)­ethanamide was more efficient at a lower effective concentration of 0.75 wt %.…”

Effective Inhibition of Carbon Steel Corrosion by Waterborne Polyurethane Based on N-tert-Butyl Diethanolamine in 2M HCl: Experimental and Computational Findings

“…Currently, more attention is being paid to environmentally friendly and biodegradable inhibitors [14][15][16][17][18]. In some countries, environmental protection organizations have introduced strict rules and regulations on bioaccumulation, biodegradability, and toxicity [19].…”