Non-Amide Kinetic Hydrate Inhibitors: Investigation of the Performance of a Series of Poly(vinylphosphonate) Diesters

摘要

The kinetic hydrate inhibitor (KHI) performances of a series of poly(dialkyl vinylphosphonate)s (PDAVPs) containing pendant phosphonate groups fully esterified with two identical alkyl chains have been assessed by conducting a suite of slow constant cooling tests at 76 bar in steel rocking cell equipment using a synthetic natural gas (SNG) that preferably forms structure II gas hydrates. The KHI performances of three PDAVPs, of roughly the same molecular weights (2838 kDa), comprising methyl (M), ethyl (E,) and isopropyl (IP) groups, respectively, were evaluated. As a result, the following ranking was disclosed: P(DIPVP) > P(DEVP) > P(DMVP). The diisopropylated P(DIPVP) homopolymer gave an average onset temperature from 10 experiments of T-o of 8.3 degrees C compared to 17.3 degrees C with deionized water and no additive. The good performance is likely related to the low cloud point (1 wt % solution in deionized water), which was measured to be 18 degrees C. Three ethylated P(DEVP)s, with molecular weights in the range 3060 kDa, were tested for KHI performances. The two higher molecular weight samples gave the best performance, which we surmise is related more to the lower cloud point of these samples than the molecular weight. A P(DMVP:DIPVP) copolymer with a high cloud point showed weak KHI effect (To = 13.1 degrees C).