Low-Dosage Hydrate Inhibitor

Lovell, D. Pakulski, M. (2003). Two low-dosage hydrate inhibitors. Journal of Petroleum Technology, 55(4), 65-68. 

The inhibition of three-phase hydrate formation is discussed in Section 4.4. These predictions enable answers to such questions as, How much methanol (or other inhibitor) is required in the free water phase to prevent hydrates at the pressures and temperatures of operation Classical empirical techniques such as that of Hammerschmidt (1934) are suitable for hand calculation and provide a qualitative understanding of inhibitor effects. It should be noted that only thermodynamic inhibitors are considered here. The new low-dosage hydrate inhibitors [LDHIs, such as kinetic inhibitors (KIs) or antiagglomerants (AAs)] do not significantly affect the thermodynamics but the kinetics of hydrate formation LDHIs are considered in Chapter 8. 

New, low dosage hydrate inhibitors (LDHIs) are being commonly used in the industry, based upon the kinetics of hydrate formation. 

Concepts and case studies on low dosage hydrate inhibitor prevention... 

Over the last decade or so, many research efforts have been focused on developing what are termed low-dosage hydrate inhibitors , or LDHIs, that potentially can kinetically inhibit hydrate formation/ LDHIs operate via a much different mechanism than thermodynamic inhibitors such as methanol. They are often effective at concentrations as low as 0.5 wt% and act by delaying the onset of hydrate formation, while thermodynamic inhibitors are effective only at much higher concentrations and act by changing the conditions of hydrate thermodynamic stability, thus shifting the phase diagram. 

Mehta, A.P. Hebert, P.B. Cadena, E.R. Weatherman, J.P. Fulfilling the promise of low dosage hydrate inhibitors journey from academic curiosity to successful field implementation. Proceedings of the Annual Offshore Technology Conference, SPE, 2002 565-571. 

Kelland, M. A., History of the development of low dosage hydrate inhibitors, Energ. Fuels, 2006, 20, 825-847. 

Fu, et al, 2002) [14] [17] [15] [1] [8]. AAs are different from both THIs and KHIs. AAs allow hydrate formation but prevent individual hydrate erystals from agglomerating together, therefore, maintain the hydroearbon system transportable (Fu, et al, 2002 Sloan and Koh, 2008) [8] [20], KHIs and AAs together are further ealled low dosage hydrate inhibitors (LDHIs) as the eoneentrations of KHIs or AAs are low (typically, less than 3%) in eomparison with those of THIs (Sloan and Koh, 2008 Kelland, 2006) [20] [12], where in some cases high eoneentrations of up to 60 mass% of MeOH or MEG may be needed to have suffieient inhibition (Brustad, et al, 2005 Cowie, et al., 2005) [5] [7],... 

Argo, C.B. Blain, R.A., Osborne, C.G., Priestley, I.D., 2000. Commercial deployment of low-dosage hydrate inhibitors in a Southern North Sea 69 km wet-gas subsea pipeline. SPE Production Facilities 15, 130-134. 

Fu, B., Neff, S., Mathur, A., Bakeev, K., 2002. Application of low-dosage hydrate inhibitors in deepwater operations. SPE Production Facilities 17,133-137. 

In addition to produced chemicals, offshore facUities generally use a range of chemicals for treatment of the oil, gas, and produced water. In particular, hydrate formation in subsea pipelines is controlled with chemicals such as methanol and glycol. A commonly used specialty chemical is a Low-Dosage Hydrate Inhibitor (LDHl). 

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