【作者】 胡军；

【导师】 樊栓狮；

【作者基本信息】 华南理工大学 ， 能源环境材料及技术， 2012， 博士

【摘要】 在石油和天然气的开采、加工和运输过程中，水合物的形成会导致管线及设备堵塞，造成严重危害，带来巨大的经济损失。动力学抑制剂代替热力学抑制剂防治水合物已经成为一种趋势，含五、七元环官能团的聚合物动力学抑制剂在油气工业得到越来越广泛的应用，但不同环状官能团对动力学抑制剂的抑制性能的影响尚不明确，其抑制机理仍需要深入研究，油气工业缺乏抑制性能好和生物降解性能好的动力学抑制剂品种。本文从分子结构设计出发，开发了含环状结构（五元环，六元环和七元环）的聚合物动力学抑制剂，研究了其对四氢呋喃（THF）和天然气水合物的抑制性能；对动力学抑制剂进行构效分析，探讨了含环状官能团聚合物的水合物抑制机理；并对动力学抑制剂的生物降解性能和对水合物颗粒粘附力的影响进行了研究；最后，挑选出性能较佳的抑制剂进行了陆上气田现场应用试验，取得了良好的效果。本文中合成了含环状官能团的三个系列动力学抑制剂，即含五元环官能团的乙烯基吡咯烷酮均聚物（HY系列），含五元-六元环官能团的乙烯基吡咯烷酮与2–乙烯基吡啶或4–乙烯基吡啶共聚物（HG系列），含七元-六元环官能团的乙烯基己内酰胺与2–乙烯基吡啶共聚物（HN系列）。对三个系列抑制剂进行了THF水合物抑制性能测试，其抑制效果良好。其中，HY4在-5°C可有效抑制水合物生成18h以上；HG15在-1oC抑制时间可达到8.5h；HN119在-1oC抑制时间达到15.7h。二乙二醇单丁醚对HY系列抑制剂具有协同抑制作用；四丁基溴化铵（TBAB）能提高HG系列抑制剂的使用过冷度、延长其抑制时间。研究含有动力学抑制剂的THF水合物颗粒粘附力大小变化规律，HY4、商业抑制剂Inhibex501作用下水合物颗粒接触面上出现了较大的粘性液桥，增大了THF水合物颗粒的粘附力；HN13、HG15、PVCap引起THF水合物颗粒表面粗糙，有效降低了水合物颗粒粘附力。在庚烷/水/天然气体系中，过冷度为10~12°C，抑制剂用量为水量的0.1wt%，对三个系列抑制剂以及含有五元环四氢呋喃官能团（PTHFMA）或链状过氧化乙烯（PEO）官能团的聚合物进行了抑制性能测试和构效分析。结果发现，含五元环官能团的聚合物中，PTHFMA-co-PEO中抑制性能最好，抑制时间达到3.4h，HY4的抑制时间为2.4h；含五元环与六元环官能团的抑制剂中，其抑制性能随着六元环官能团增加而提高，HG13和HG15的抑制时间超过4h；含七元环与六元环官能团的抑制剂中六元环对其抑制性能提高有限，HN13和HN19的抑制时间在4h以上，HN119抑制时间可达到5.6h；含有七元环和链状官能团的PEO-co-Vcap的抑制时间为3.5h。通过构效分析，认为在水合物形成的气体溶解和水合物成核阶段，含环状官能团的动力学抑制剂的抑制性能与它们的亲水疏水性质、官能团种类以及环的形状有关；在水合物晶体生长阶段，动力学抑制性能的强弱与其在水合物晶体上的吸附能力、聚合物的分子大小以及在溶液中的构象有关。聚合物中环状官能团的动力学抑制性能强弱顺序为七元环>六元环>五元环。测定了含动力学抑制剂的溶液在生物降解前后的COD（化学需氧量）和降解过程中的BOD（生化需氧量），研究了动力学抑制的生物降解性能。生物降解性能最好的是HG系列，其值在0.67~0.79之间；HY4的生物降解性能为0.61；HN系列的生物降解性能在0.30~0.48之间。动力学抑制剂的生物降解性能的大小主要由其官能团的类型决定，引入2–乙烯基吡啶能提高动力学抑制剂的生物降解性能。为考察开发的动力学抑制剂实际使用效果，将动力学抑制剂HY4应用到陕北气田。连续10天试验期间，HY4对凝析油含量低的天然气具有较好的水合物抑制效果。使用HY4可使甲醇用量降低超过70%，与甲醇相比应用成本接近，节省了污水处理成本。更多还原

【Abstract】 The pipeline and gathering production equipment can be blocked by hydrates, which aredetrimental to the natural gas and oil exploitation, gathering and processing, resulting in hugeeconomic losses. Kinetic hydrate inhibitors (KHIs) are more favorably utilized to inhibit theformation of hydrates than thermodynamic inhibitors (TIs). From the mid-1990s, KHIs withfive ring or seven ring functional groups have been utilized in oil and gas industry more andmore widely. However, the impact and mechanisim of KHIs’ ring members on hydrateinhibition is still not clear, and KHIs with good biodegradability and inhibition performance isin urgent need in oil and gas industry.In this study, new varieties of KHIs with different ring functional groups were designedand synthesized, and their performance in THF solution and water/gas/oil system to inhibithydrate formation was investigated. The biodegradability of KHIs in water was studied, andthe interaction between the hydrate particles with KHIs in n-decane was investigated. On thebasis of this study, one industrial product of KHIs was applied in gas field domestically.Three series of hydrate kinetic inhibitors were synthesized, namely PVP combinedinhibitors (HY), poly(N-vinyl2-pyrrolidone-co-4/2-vinyl pyridine)(HG) and poly(vinylcaprolactam-co-2-vinyl pyridine)(HN).The induction time of three series of hydrate kinetic inhibitors were tested in THFsolution. It was found that HY4inhibited THF hydrate formation more than18h with thesynergist of diethylene glycol monoethyl ether. The introduction of2-vinyl pyridine inN-vinyl pyrrolidone polymer can improve the polymer’s THF hydrate inhibition ability, andTBAB can improve HG’ inhibition ability in the aspects of enlarging subcooling andprolonging inhibitory time. HN’s performance was superior to Inhibex501, and HN119couldinhibit THF hydrate formation for15.7h at-1oC. The adhesion forces of tetrahydrofuran(THF) hydrate particles in n-decane in the presence of some KHIs were measured. With PVPand Inhibex501, the contact surface of hydrate particles had larger viscous liquid bridgewhich promoted the adhesion force. While PVCap, HN13and HG15caused THF hydrateparticle surface roughness, thus contributing to lower adhesion force.The three series of KHIs and THF/PEO group-contained polymers’ inhibitionperformance on natural gas hydrate was carried out. The mesuring system was heptane/water/gas at a subcooling of about10~12°C, and the amount of inhibitor tested was0.1wt%according to the water quality. It was found that the polymer containing five ring functional groups, PTHFMA-co-PEO inhibited natural gas formation for3.4h, and the inhibition time ofHY4was2.4h. With the amount of six functional groups increasing in the polymers of HG,their inhibitory performance was improved, and HG13and HG15could inhibit hydrateformation more than4h. As for the performance of seven and six ring functional groups ofHN, HN13and HN19’s inhibition time were more than4h, while HN119’s inhibition timecould be up to5.6h. PEO-co-VCap with seven ring functional groups can inhibit gas hydratefor3.5h. Based on the above results, it was proposed that in the gas dissolution and hydratenucleation stage, the performance of KHIs was determined by their hydrophobic andhydrophilic properties, the types of functional groups and ring members; on the hydratecrystal growth stage, the performance of KHIs was depended on their adsorption capacityonto the hydrate crystal, the polymer molecular size and polymer conformation in solution.The performance order of functional groups in polmers was seven ring> six ring> five ring.The biodegradability of KHIs was studied through their COD and BOD in aqueoussolution. HG’s biodegradability were at about0.7, compared with HY4having a increaseabout10%, and HG17’s biodegradability was prominently0.79; HN’s biodegradability wasat about0.3~0.5. It was shown that the biodegradability of KHIs was determined by theirfunctional groups. The introduction of2-vinyl pyridine can improve the biodegradability ofKHIs.To evaluate the actual operational performance of KHIs, HY4was applied in anonshore gas field. HY4had a good hydrate inhibition effect on low condensate content naturalgas, and can prevent effectively gas hydrate pipeline blockage in the test period of10days.The methanol dosage can be reduced by over70%with HY4. HY4’s application cost wasclose to methanol, but the sewage treatment was avoided.更多还原