Page 262 - Handbook Of Multiphase Flow Assurance

Molecular modeling 261

FIG. 10.31 Conformation of the PVCap polymer docked on sII hydrate. Dashed lines in the hydrate lattice repre-
sent hydrogen bonds. PVCap is not hydrogen bonded to water molecules in hydrate.

FIG. 10.32 Examples of natural antifreeze polypeptide and of kinetic hydrate inhibitors.

Conclusions for docking study
Molecular mechanics was used for examining potential kinetic inhibitors' interaction with
ice or gas hydrate surface. Docking of the winter flounder polypeptide on three surfaces of
ice Ih and surfaces of sI and sII hydrates was performed. Adsorption energy is favorable.
Simulation provides some insight into the ice inhibition mechanism. Energies for VC-713
docking on water crystals are shown to be unfavorable. Long DMAEMA groups sterically
hinder the ability of a VC-713 polymer chain to lie flat on adsorption site. Results for the other
kinetic hydrate inhibitors PVP and PVCap are very similar to the results for winter flounder