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The unscheduled formation of gas hydrate plugs in oil and gas pipelines, which can lead to serious mechanical and personnel damage, is a problematic issue in the petroleum industry. Traditionally, thermodynamic inhibitors such as methanol have been used to control the formation of gas hydrates, but due to the large expenses and ecological risks associated with its use there is increased interest in the use of alternative hydrate inhibitors. They include kinetic inhibitors (KIs) and antiagglomerants (AAs) and as their names imply, function by interfering with the kinetics of hydrate formation and hydrate agglomeration. Recently, antifreeze proteins (AFPs) have shown to inhibit hydrates and have been proposed as hydrate inhibitors. Normally, AFPs function to protect the tissues of various organisms during freezing conditions. Initially they were found in polar fish, and were later recognized in insects, plants and microorganisms. AFPs are thought to function by lowering the freezing point of water through an adsorption-inhibition mechanism. This thesis has shown that antifreeze proteins (AFPs) are able to modify the crystal morphologies of structure II (sII) tetrahydrofuran (THF) similarly to the KI poly-N-vinylpyrrolidone (PVP) by adhering to the hydrate surface and inhibiting crystal growth. The AFPs were also tested on a high-pressure sII methane/ethane/propane hydrate and proved to have superior hydrate inhibition to PVP. Yet, the expense of purifying AFPs makes them impractical for industrial purposes, thus investigations into the use of cold-adapted bacteria as hydrate inhibitors proved that isolates capable of adsorbing to THF hydrate showed the most effective THF hydrate inhibition. These findings suggest a potential for the future development of biologically-based hydrate inhibitors. / Thesis (Master, Biology) -- Queen's University, 2009-09-01 10:04:00.72

The formation of gas hydrates in the oil and gas industry causes numerous problems that require costly solutions and operation downtime. A great deal of hydrate research has focused on their prevention either through kinetic or thermodynamic inhibitors. Recently, antifreeze proteins (AFPs) produced by cold adapted organisms have been found to have a kinetic inhibitory effect on clathrate hydrates. / Kinetic experiments were conducted on the methane-water system in the presence of AFPs by measuring the gas uptake during the formation of methane hydrate in a 610 cc high pressure crystallizer. These experiments were performed at temperatures ranging from 277.15 K to 280.65 K, pressures of 5800 KPa to 8100 KPa and at an AFP concentration of 0.01 mM. / The results of these experiments showed that the presence of AFPs affect methane hydrate formation in multiple ways. They were shown to increase the nucleation time, reduce the initial growth rate of methane hydrate at the time of nucleation and there was evidence to suggest that they also have an anti-agglomerating effect on hydrate crystals.

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Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains xi, 208 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references (p. 205-208).

Thesis (Ph. D.)--Columbia University, 1918. / Vita. Includes bibliographical references.

Thesis (Ph.D.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2008. / Committee Chair: J. Carlos Santamarina; Committee Member: Carolyn D. Ruppel; Committee Member: Costas Tsouris; Committee Member: Glenn J. Rix; Committee Member: J. David Frost

Thesis (Ph. D.)--Johns Hopkins University. / Biography.

Thesis (Ph. D.)--Johns Hopkins University. / Biography.