Metastable ionic cubic structure I clathrate hydrate formed with tetra-n-butylammonium bromide

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Effect of the Degree of Oil Biodegradation on the Crystallization of Methane Hydrate and Ice in Water-Oil Emulsions

To study the influence exerted by oxidized oil components on the nucleation and growth of gas hydrates the nucleation of methane hydrate and ice in 50 wt % emulsions of oil in native oil and two samples of the same oil subjected to biodegradation for 30 and 60 days (samples N, V30, and V60, respectively) were examined. In the course of measurements, the samples were cooled to–15°C at a constant rate of 0.14 deg min^–1 and then heated to the initial temperature. The initial methane pressure in the system was 15 MPa at 20°C. In the process, the temperatures were recorded at which heat effects corresponding to the formation of hydrate/ice and the melting of these. In the case of emulsion N, no exothermic effects were manifested in the cooling stage. In the heating stage, the endothermic effects of ice melting were found in half of the samples. No effects corresponding to the decomposition of the hydrate were observed. In experiment with V30 samples, the formation of the hydrate and ice was manifested as strong exothermic effects. Ice was formed in all the experiments, and the hydrate, only in 21% of the samples. Finally, in experiments with V60, ice and the hydrate were formed in 54 and 13% of cases, respectively. Their formation was manifested as weak exothermic effects in the cooling stage. Thus, it was demonstrated that the biodegradation level of oil samples affects the nucleation of methane hydrate and ice in emulsions formed on the basis of these samples.

     

Influence of petroleum fractions on the process of methane hydrate self-preservation

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Unusual examples of methane hydrate nucleation in bilayer water–oil systems

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Effect of reactor wall material on the nucleation of methane hydrate in water-in-oil emulsions

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Performance of Waterborne Polyurethanes in Inhibition of Gas Hydrate Formation and Corrosion: Influence of Hydrophobic Fragments

The design of new dual-function inhibitors simultaneously preventing hydrate formation and corrosion is a relevant issue for the oil and gas industry. The structure-property relationship for a promising class of hybrid inhibitors based on waterborne polyurethanes (WPU) was studied in this work. Variation of diethanolamines differing in the size and branching of N-substituents (methyl, n-butyl, and tert-butyl), as well as the amount of these groups, allowed the structure of polymer molecules to be preset during their synthesis. To assess the hydrate and corrosion inhibition efficiency of developed reagents pressurized rocking cells, electrochemistry and weight-loss techniques were used. A distinct effect of these variables altering the hydrophobicity of obtained compounds on their target properties was revealed. Polymers with increased content of diethanolamine fragments with n- or tert-butyl as N-substituent (WPU-6 and WPU-7, respectively) worked as dual-function inhibitors, showing nearly the same efficiency as commercial ones at low concentration (0.25 wt%), with the branched one (tert-butyl; WPU-7) turning out to be more effective as a corrosion inhibitor. Commercial kinetic hydrate inhibitor Luvicap 55 W and corrosion inhibitor Armohib CI-28 were taken as reference samples. Preliminary study reveals that WPU-6 and WPU-7 polyurethanes as well as Luvicap 55 W are all poorly biodegradable compounds; BOD_t/COD_cr (ratio of Biochemical oxygen demand and Chemical oxygen demand) value is 0.234 and 0.294 for WPU-6 and WPU-7, respectively, compared to 0.251 for commercial kinetic hydrate inhibitor Luvicap 55 W. Since the obtained polyurethanes have a bifunctional effect and operate at low enough concentrations, their employment is expected to reduce both operating costs and environmental impact.     

Laboratory Reactor for Visual Examination of Formation/Decomposition of Gas Hydrates in Water-Oil Systems

Russian Journal of Applied Chemistry - Design of an installation for studying the formation and decomposition of gas hydrates in water-oil systems via visual examination and video recording under...