A Study of the Kinetic Hydrate Inhibitor Performance and Seawater Biodegradability of a Series of Poly(2-alkyl-2-oxazoline)s

Abstract

Kinetic hydrate inhibitors (KHIs) have been used successfully in the field for about the last 14 years to prevent gas hydrate formation mostly in gas and oilfield production lines. They work by delaying the nucleation and often also the growth of gas hydrate crystals for periods of time dependent on the subcooling in the system. Poly(2-alkyl-2-oxazoline)s [or poly(N-acylalkylene imine)s] are a known class of KHI, but no work has previously been published detailing a systematic study of structure versus performance. In this paper we report the KHI performance of poly(2-alkyl-2-oxazoline) homopolymers and statistical copolymers with alkyl side groups up to four carbon atoms. The study includes hydrate crystal growth tests on structure II tetrahydrofuran hydrate crystals as well as high pressure nucleation and crystal growth studies on a synthetic natural gas mixture giving structure II hydrates. Seawater biodegradation studies on all the polymers according to the OECD306 procedure indicate that they are all poorly biodegradable (<20% in 28 days).

The Effect of Hofmeister Salts on the LCST Transition of Poly(2‐oxazoline)s with Varying Hydrophilicity

“…The investigated polymers PEtOx, PnPropOx, and PiPropOx, with a monomer to initiator ratio (M/I) of 100 were synthesized in a similar way as described previously. [27,28] The synthesis of the POEtOxMA comb polymer, consisting of 5 units EtOx and 39 units MA, was recently reported in ref. [29] .…”

Polyoxazoline Thermoresponsive Micelles as Radionuclide Delivery Systems

“…The cloud point temperature was slightly higher at lower copolymer concentrations in a solution and this concentration dependence was somehow more pronounced in statistic IprOX-co-BuOX copolymers compared to pure IprOX homopolymer (see Supporting Information), probably due to statistical intermolecular heterogeneity (similar to that reported for other polyoxazoline copolymers). [20,21] The triblock copolymers poly[MeOX-b-(IprOX-co-BuOX)-b-MeOX] were synthesized in high yields (> 90% after purification). Their molar weights were only slightly lower than theoretically expected (found M w ¼ 8.58 kDa in the range AE0.34 kDa) with slightly higher polydispersities (I ¼ 1.39 in the range AE0.04) compared to the model copolymers poly(IprOX-co-BuOX); see Supporting Information for a typical size-exclusion chromatogram.…”

Polyethylene Glycol Drilling Fluid for Drilling in Marine Gas Hydrates-Bearing Sediments: An Experimental Study

“…Water-based polymer drilling fluids with a high salt content and partially hydrolyzed polyacrylamide (PHPA) have been successfully used in many deep-water drilling activities [20,21]. In most cases, the thermodynamic inhibitors are added into drilling fluids to prevent gas-hydrate formation in deep water drilling, whereas the results of kinetic hydrate inhibitors (KHIs) are still under investigation [22][23][24]. Compared with traditional thermodynamic inhibitors, kinetic inhibitors are effective at very low addition (generally 0.01-1 wt%), which can significantly reduce the drilling cost.…”