Experimental investigation on hydrate anti-agglomerant for oil-free systems in the production pipe of marine natural gas hydrates

Novel Biosurfactants for Effective Inhibition of Gas Hydrate Agglomeration and Corrosion in Offshore Oil and Gas Pipelines

“…15,16 Rhamnolipids, hydroxycarbamide, sorbitan fatty acid esters, quaternary ammonium salts, and amine oxides are wellknown AAs. 1,15 Among them, quaternary ammonium salts have been considered the most effective AAs at high supercooling temperatures. 17 However, low biodegradability and toxicity are significant drawbacks for their application in deep-water oil and gas exploration.…”

“…Although THIs are practical, high concentrations (20–50 wt %) are often required to inhibit hydrate formation. − Conversely, low-dosage hydrate inhibitors including kinetic hydrate inhibitors (KHIs) and anti-agglomerants (AAs) work at concentrations between 0.1 and 2.0 wt % by affecting the properties of hydrate surfaces. , KHIs (usually water-soluble polymers) affect the water network of hydrogen bonding. They may slow nucleation or the rate of hydrate growth, but most of them are ineffective at high supercooling (i.e., >10 °C) in deep-sea environments. ,− AAs (often surfactants) are a promising option as they exhibit inhibitory effects by preventing the aggregation of hydrate particles’ low effective concentrations and ensuring hydrates in the form of a transportable slurry, which significantly reduces operating costs. , Rhamnolipids, hydroxycarbamide, sorbitan fatty acid esters, quaternary ammonium salts, and amine oxides are well-known AAs. , Among them, quaternary ammonium salts have been considered the most effective AAs at high supercooling temperatures . However, low biodegradability and toxicity are significant drawbacks for their application in deep-water oil and gas exploration. , Therefore, developing eco-friendly AAs and enhancing their inhibition activity is urgently needed and would be a favorable green alternative given the marine environment.…”

Effect of SDS on the Formation and Blockage Characteristics of the CH4 Hydrate in a Flow Loop

“…As a low-carbon and efficient clean energy source, if the natural gas contained in submarine gas hydrate can be extracted to replace the traditional fossil fuels, it will reduce production costs, improve the production efficiency, and greatly reduce the pollution caused by the traditional fossil energy. To transport the extracted natural gas, it is often necessary to lay pipelines that contain only gas and water phases on the seafloor . Pipeline blockage caused by the hydrate formation is a difficult problem when mining this type of hydrate.…”

“…To transport the extracted natural gas, it is often necessary to lay pipelines that contain only gas and water phases on the seafloor. 16 Pipeline blockage caused by the hydrate formation is a difficult problem when mining this type of hydrate. For example, in 2017, during the second trial production of submarine hydrate in Japan, production was interrupted several times due to the hydrate blockage.…”

“…However, in recent years, some scholars have found that a small number of AAs still have an antiagglomeration effect in oil-free systems. For example, DCA can prevent cyclopentane hydrate from agglomerating in an oil-free system, 16 and CO 2 hydrate slurry can flow stably without blockage under the action of Tween-80. 22 AAs that can be applied in water-based systems have positive implications for the development of subsea gas hydrates.…”