To prevent hydrate plugging conditions in the transportation of oil/gas in multiphase flowlines, one of the key processes to control is the agglomeration/deposition of hydrate particles, which are determined by the cohesive/adhesive forces. Previous studies reporting measurements of the cohesive/adhesive force between hydrate particles used cyclopentane hydrate particles in a low-pressure micro...

Phase equilibria involving gas hydrates are of importance in natural gas recovery and carbon dioxide sequestration. Due to high equilibrium pressures twoand three-phase equilibria for gas hydrates containing systems have been computed using equations of state and van der Waals and Platteeuw model for fugacity of guest components in gas hydrates. So far the inhibition effect has been accounted f...

We present molecular dynamics simulation evidence of spontaneous formation of quasi-one-dimensional (Q1D) hydrogen gas hydrates within single-walled carbon nanotubes (SW-CNTs) of nanometer-sized diameter (1-1.3 nm) near ambient temperature. Contrary to conventional 3D gas hydrates in which the guest molecules are typically contained in individual and isolated cages in the host lattice, the gues...

The recovery of CH4 gas from natural hydrate formations by injection of industrially emitted CO2 is considered to be a promising solution to simultaneously access an unconventional fossil fuel reserve and counteract atmospheric CO2 increase. CO2 obtained from industrial processes may contain traces of impurities such as SO2 or NOx and natural gas hydrates may contain higher hydrocarbons such as...

An experimental study was conducted to evaluate the feasibility of employing binary hydrates as a medium for H2 storage. Two reagents, tetrahydrofuran (THF) and tetra-n-butylammonium bromide (TBAB), which had been reported previously to have potential to form binary hydrates with H2 under favorable conditions (i.e., low pressures and high temperatures), were investigated using differential scan...

Gas hydrates could show an unexpected high stability at conditions out of thermodynamic equilibrium, which is called the self-preservation effect. The mechanism of the effect for methane hydrates is here investigated via molecular dynamics simulations, in which an NVT/E method is introduced to represent different levels of heat transfer resistance. Our simulations suggest a coupling between the...

Methane hydrate dissociation at negative temperatures was studied experimentally for different artificial and natural samples, differing by macro- and micro-structural parameters. Four characteristic dissociation types are discussed in the paper. The internal kinetics of artificial granule gas hydrates and clathrate hydrates in coal is dependent on the porosity, defectiveness and gas filtration...

The complex interplay of temperature and water activity (aw) / relative humidity (RH) on the solid form stability and transformation pathways of three hydrates (HyA, HyB and HyC), an isostructural dehydrate (HyAdehy ), an anhydrate (AH) and amorphous brucine has been elucidated and the transformation enthalpies quantified. The dihydrate (HyA) shows a non-stoichimetric (de)hydration behavior at ...

Existence of gas-hydrates in the marine sediments elevates the velocity of seismic waves, whereas even a small amount of underlying free-gas decreases the seismic velocity considerably. These changes in velocities can be used for the assessment of gas-hydrates. The traveltime inversion is an effective method to derive a 2-D velocity structure from the seismic data. We have applied the method to...

The discovery that methane from dissociation of gas-hydrates could be an important factor in the global carbon cycle resolves the major discrepancy in estimates of the increase of terrestrial biomass from the Last Glacial period to the present. Carbon isotope budgeting using the marine carbon isotopic record results in an estimate centered around 500 GtC; whereas palaeovegetation reconstruction...