Влияние низших спиртов на образование гидрата метана при температуре ниже точки плавления льда

Abstract

This work revealed that most water-soluble compounds have a dual nature (thermodynamic promotion or hydrate inhibition) depending on thermobaric conditions. Indeed, by lowering the melting point of ice, water-soluble organic compounds expandthe region of water-containing liquid phase existence below 0°C. This work considered typical thermodynamic hydrate inhibitors as alcohols (methanol, ethanol, and isopropanol). It turned out that even methanol does not exhibit inhibitory properties below the ice crystallization line, and it does not affect the equilibrium conditions of methane hydrate formation. In this case, the observed four-phase hydrate-ice-solution-gas equilibrium either corresponds to the hydrate-ice-gas line for the water-methane system (in the case of methanol) or lies at higher temperatures (in the case of ethanol and isopropanol). This allowed us to assume that practicallyany water-soluble organic compounds will either exhibit the properties of thermodynamic hydrate promoters in a specific temperature range below 0°C or will not affect the hydrate-ice-gas equilibrium. In addition, the presence of the ice and an aqueous liquid mixture in the system accelerates the hydrate growth (compared to the hydrate growth from the bulk phase of ice). It should alsobe noted that, unlike conventional thermodynamic promoters, methanol does not alter the methane hydrate's structure and gas capacity, which is more favorable. The data obtained can contribute to developing hydrate-based technologies for gas storage and separation of gas mixtures.