(411f) Phase Equilibrium Measurements for Semi-Clathrate Hydrates of Water+Decane+Carbon Dioxide+Tbab Systems

Regardless of developments in the energy sector related to the search of renewable energies, it is a fact that fossil fuels still dominate the market, so its use is very important. In recent years, the oil industry record an increase of produced water during the extraction of these resources in oil production wells, so it is necessary to develop a low cost effective process for separating water from oil. During the extraction process the oil-gas-water phases are present. A novel alternative that can be considered for the separation of these phases is the gas hydrates formation. Gas hydrates are crystalline compounds similar to ice, composed of water molecules that form a clathrate structure (host molecule) and a molecule of a gas (guest molecule), which is encapsulated within the structure. Hydrate formation is due to a physical process, so there is no chemical interaction between the host and guest molecules at high pressures and low temperatures. However, given the energy costs, the separation of produced water must be carried out at near ambient conditions. This is possible in hydrate formation by adding a thermodynamic promoter, shifting the phase equilibrium at ambient conditions.

In this work, we reported the dissociation conditions for semi-clathrate hydrates of Water+Decane+Carbon Dioxide+tetra-n-butylammonium bromide (TBAB) systems. The dissociation conditions have been determinate using an apparatus based in an isochoric technique and designed to operate at pressure up to 40 MPa and at temperature range of (258.15-373.15) K. The experimental measurements were performed at temperature range of (275-282) K and pressures up to 4 MPa. The combined expanded uncertainties of the dissociation conditions were evaluated to be less than 0.012 MPa, 0.020 K and 0.0020 for pressure, temperature and mass fraction, respectively.