Gas hydrate often occurs in natural gas pipelines and process equipment at high pressure and low temperature. Methanol as a hydrate inhibitor injects to the potential hydrate systems and then recovers from the gas phase and re-injects to the system. Since methanol loss imposes an extra cost on the gas processing plants, designing a process for its reduction is necessary. In this study, an accur...

The anhydrate and the stoichiometric tetarto-hydrate of pyrogallol (0.25 mol water per mol pyrogallol) are both storage stable at ambient conditions, provided that they are phase pure, with the system being at equilibrium at aw (water activity) = 0.15 at 25 °C. Structures have been derived from single crystal and powder X-ray diffraction data for the anhydrate and hydrate, respectively. It is n...

Iran's proved natural gas reserves are the world's second largest reserves. Mainly, because of different climate changes and different reservoirs characterizations, studying the behavior of producing outcome fluids and their transportation, is of major interest. One of the main problems occur in the gas reservoirs is related to the hydrate formation while producing from a well, either in produc...

Motivated by recent experiments showing the promise of noble gases as cryoprotectants, we perform molecular dynamics modeling of phase transitions in water with xenon under cooling. We follow the structure and dynamics of xenon water solution as a function of temperature. Homogeneous nucleation of clathrate hydrate phase is observed and characterized. As the temperature is further reduced we ob...

Using a volumetric technique, a T-P diagram of phase transformations between the hydrogen-rich clathrate hydrate (sII phase), hydrogen-filled ice II (C(1) phase), and the liquid (L) is studied in the H(2)O-H(2) system at pressures up to 4.7 kbar and temperatures from -22 to +15 degrees C. The volume and entropy effects of these transformations are established in the vicinity of the triple point...

This paper reports the formation and dissociation pattern of hydrate crystals with varying compositions CH4 CO2 in porous media. Direct visualization was carried out using a high-pressure, water-wet, silicon wafer-based micromodel pore network resembling sandstone rock. Hydrate were formed under reservoir conditions (P = 45–65 bar T 1.7–3.5 °C) from either two-phase system consisting liquid wat...

Understanding of CO2 hydrate–liquid water two-phase equilibrium is very important for storage in deep sea and submarine sediments. This study proposed an accurate thermodynamic model to calculate solubility pure seawater at (HLWE). The van der Waals–Platteeuw coupling with angle-dependent ab initio intermolecular potentials was used the chemical potential hydrate phase. Two methods were describ...

Nonequilibrium molecular-dynamics simulations have been carried out at 276.65 K and 68 bar for the dissolution of spherical methane hydrate crystallites surrounded by a liquid phase. The liquid was composed of pure water or a water-methane mixture ranging in methane composition from 50% to 100% of the corresponding theoretical maximum for the hydrate and ranged in size from about 1600 to 2200 w...