Gas hydrates are crystalline solids formed from mixtures of water and low molecular weight compounds, referred to as hydrate formers, that typically are gases at ambient conditions (1). Generally, hydrates are formed in the laboratory from two-phase systems by contacting a hydrate former or formers in the gas or liquid phase with liquid water and increasing the pressure until crystalline hydrat...

We consider a computational model for the evolution of methane hydrates in subsurface. Methane hydrates, an ice-like compound abundant in subsea sediments and unstable in standard conditions, are an environmental hazard and simultaneously an energy source. Our multiphysics model includes multiphase multicomponent mass conservation equations and several variants of energy balance equation with o...

The low-frequency region (below 175 cm−1) of the spectra of solid samples can provide valuable information on vibrational modes related to large amplitude motions, intermolecular vibrations or vibrations associated to weak linkages. Whereas far-infrared spectroscopy exhibits rather broad bands for solid hydrates, among other drawbacks of this technique, Raman spectroscopy produces narrow signal...

The hydration behaviour of Ca3Al2O6, Ca12Al14O33 and CaAl2O4 with added amorphous silica at 40, 65 and 90 1C has been studied for periods ranging from 1 to 31 days. In hydrated samples crystalline phases like katoite (Ca3Al2(SiO4)3 x(OH)4x) and gibbsite, Al(OH)3, were identified, likewise amorphous phases like Al(OH)x, calcium silicate hydrates, C–S–H, and calcium aluminosilicate hydrates, C–S–...

INTRODUCXION Gas hydrates are crystalline molecular complexes formed from mixtures of water and suitably sized gas molecules. Based on hydrogen bonding, water molecules form unstable lattice structures with several interstitial cavities. The gas molecules can occupy the lattice cavities and, when a minimum number of cavities are occupied, the crystalline structure becomes stable and solid gas h...

Sir Humphry Davy witnessed the first chlorine hydrate crystallizing in 1811. Couple of century later his discovery, natural gas hydrates has begun to play an important role in energy business. From being a mere chemical curiosity, they have proven to be a nuisance for the natural gas industry. The problem of hydrate induced blockage in “wet gas” flow systems has been widely reported and became ...

The crystal structures of the tri- and tetrahydrate of tin tetrachloride, viz. diaquatetrachlorotin(IV) monohydrate, [SnCl(4)(H(2)O)(2)].H(2)O, and diaquatetrachlorotin(IV) dihydrate, [SnCl(4)(H(2)O)(2)].2H(2)O, are reported and shown to contain the cis-[SnCl(4)(H(2)O)(2)] species and water molecules in both cases. The trihydrate contains chains of the tin species linked by a single hydrogen-bo...

Introduction: The dominant naturally-occurring members of the MgSO4·nH2O series on Earth are epsomite (MgSO4·7H2O), hexahydrite (MgSO4·6H2O), and kieserite (MgSO4·H2O). In addition, other magnesium sulfate hydrates (sanderite 2H2O, starkeyite 4H2O, pentahydrite 5H2O) have been identified as efflorescent salts in limited localities in the United States, Chile, and Germany. Chipera et al., [1,2] ...