To gain insight into the hydrate crystal growth inhibitor (HCGIs) mechanism, we have studied various quaternary ammonium ionic liquid salts (QAILs) and phosphonium salts for their ability to prevent structure II (sII) hydrate crystal growth. We tested polyvinylpyrrolidone (PVP), polyvinylcaprolactam (PVCap), tetrapropylammonium bromide (TPrAB), tetrabutylammonium bromide (TBAB), tetrapentylammonium bromide (TPeAB), tetrahexylammonium bromide (THexAB), and tetrabutylphosphonium bromide (TBPB) in a tetrahydrofuran (THF) sII hydrate system using a unidirectional growth apparatus to determine the concentration and growth rate dependence. The growth rates of TPrAB, TBAB, and THexAB were found to be critical in the region of low growth rate, with the degree of supercooling ΔT becoming 0 for these additives in the low-growth-rate region. In contrast, PVP, PVCap, TPeAB, and TBPB remained effective at the lowest growth rate of V = 0.04 μm s^–1. These trends can be explained by the residence time on the crystal surface of the HCGI, τ, and duration time of crystal growth.

中文翻译：

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四氢呋喃水合物晶体生长抑制剂的性能及季铵盐和磷盐的机理

为了深入了解水合物晶体生长抑制剂（HCGI）的机理，我们研究了各种季铵离子液体盐（QAIL）和phospho盐具有防止结构II（sII）水合物晶体生长的能力。我们在无水乙醇中测试了聚乙烯吡咯烷酮（PVP），聚乙烯己内酰胺（PVCap），四丙基溴化铵（TPrAB），四丁基溴化铵（TBAB），四戊基溴化铵（TPeAB），四己基溴化铵（THexAB）和四丁基溴化四氢呋喃二水合物TBPB该系统使用单向生长设备来确定浓度和生长速率依赖性。TPrAB，TBAB和THexAB的生长速率在过低冷却程度ΔT的低生长速率区域中至关重要。这些添加剂在低增长率区域变为0。相比之下，PVP，PVCap，TPeAB和TBPB在V = 0.04μms ^–1的最低增长率下仍然有效。这些趋势可以通过HCGI在晶体表面的停留时间，τ和晶体生长的持续时间来解释。