关键词: 气体水合物, 相图, 四相点, 数值模拟, 相平衡

Abstract:

With the deepening research on gas hydrates in carbon capture and oil-gas transportation, the study to their phase equilibrium is significantly important. The gas forming hydrates can be either pure components or mixtures. Hydrate formation involves three- or four-phase equilibria, including I-H-V (ice-hydrate-vapor), L_w-H-V (liquid water-hydrate-vapor), L_w-H-L_HC (liquid water-hydrate-liquid hydrocarbon), and L_w-H-V-L_HC (liquid water-hydrate-vapor-liquid hydrocarbon). The phase diagrams of hydrates formed by different gas compositions exhibit notable differences, particularly in the number of four-phase points. This paper focuses on methane, nitrogen, carbon dioxide, propane and natural gas mixture systems, discussing numerical calculation methods for hydrate phase diagrams containing one or two four-phase points and four-phase lines. Numerical simulations are conducted using the independently developed SimTech Simulator, and the results are compared with those from the commercial software Pro/Ⅱ, validating the reliability of the Simulator.

Key words: gas hydrate, phase diagram, four-phase point, numerical simulation, phase equilibrium