INHIBITION OF CRYSTAL-GROWTH IN METHANE HYDRATE

Computer modelling has been used to investigate the viability of using a non-toxic, water-soluble polymer, polyvinylpyrrolidone (PVP), to in hibit gas hydrate formation. Monte Carte calculations have been used t o study the adsorption of monomer, dimer, tetramer and octamer PVP uni ts on different {001} surfaces of a type I hydrate; various polymer ta cticities have also been considered. Adsorption has been found to occu r predominantly through the formation of two hydrogen bonds between th e pyrrolidone oxygen and the water surface, and thus the location of a dsorption sites depended on the availability of pendant hydrogens on t he hydrate surface. PVP chains were generally found to lie flat on the surface, although there was some evidence of loops forming for the oc tamer. The results indicate that inhibition via adsorption of PVP at h ydrate growth sites is viable, but that the main factors influencing t he adsorption are inherently statistical.