LAUSR

Most polymers used in commercial kinetic hydrate inhibitor (KHI) formulations show thermoresponsive behavior in aqueous solution. This means that they exhibit a cloud point (or lower critical solution temperature) which is often low and not far above the equilibrium temperature for gas hydrate formation. For example, poly(N-vinyl caprolactam) has a cloud point of about 30–40 °C and poly(N-isopropylmethacrylamide) has a cloud point of about 35–45 °C depending on the molecular weight and method of polymerization. This report is divided into two parts. First, we review previous KHI studies and show that low cloud point is a useful factor, but not the most critical factor, to be considered within a specific class of polymers in designing a high-performance KHI. This statement is supported in the second part of this report, which is an experimental KHI study. In this study, we present results of KHI tests for a natural gas/deionized water structure II gas hydrate-forming system using low cloud point polymers w...