Page 251 - Handbook Of Multiphase Flow Assurance

250 10. Research methods in flow assurance

TABLE 10.7 Hydrate equilibrium calculation.
Hydrate equilibrium for Xe + neohexane + water system
T, K P, kPa Pcalc
278.15 241.25 264.22
280.65 344.74 333.38
283.15 452.52 421.12
285.65 571.21 532.8
288.15 733.593 673.68

sI hydrate equilibrium for Xe + water system
T, K P, kPa Pcalc
278.15 N/A
280.65 N/A
283.15 426.2743 396.2
285.65 N/A
288.15 698.4332 640.66

Normalized changes in xenon pressure required as a result of
having neohexane in the system.
T, K △P/P(3 component)
278.15 N/A
280.65 N/A
283.15 0.057999
285.65 N/A
288.15 0.047928

Evaluation of the biomolecular computer studies

Simulation of the macromolecules docking on the surface of water crystals showed the
preferential orientations and interaction energies between macromolecules and the surface. It
was concluded from the resulting low energies of interaction that Winter Flounder polypep-
tide biomolecule, PVP and PVCap molecules are able to adsorb on ice, sI and sII hydrate sur-
faces. Very high interaction energy was shown for the VC-713 polymer which suggests that
it cannot dock on water crystals. The reason for inability of VC-713 to dock on water crystal
is considered to be the DMAEMA (dimethylaminoethylmethacrylate) monomers presence in
the polymer chain. This monomer acts as a buffer between polymer and crystal.
Verification of the water models was performed. The simple point charge (SPC) water model
was shown to adequately represent the structural and thermodynamic properties of real water.
SPC water model is recommended as a choice among all water models available in SYBYL.