【作者】 李友清；

【导师】 唐和清；

【作者基本信息】 华中科技大学 ， 材料物理与化学， 2008， 博士

【摘要】 油田现场存在两类重要问题,其一是污水系统中机械和化学的联合作用导致管道设备的严重腐蚀,其二是由于腐蚀穿孔引起的石油类有机污染物外泄而造成的严重环境污染。为了研究油田现场的CO2腐蚀,通常采用3%NaCl溶液作为模拟溶液,但这会造成与现场工况的偏离,而针对油气井缓蚀剂的研究主要是静态和低流速的室内模拟,这将明显偏离于高流速含砂的多相流条件下的腐蚀状况。而在现场高流速和含砂的腐蚀介质中,缓蚀剂已无法发挥其保护作用,需要选用耐冲刷腐蚀的涂层保护技术。环氧树脂涂覆是常用的对冲刷腐蚀进行修复处理的技术,但在油田高温和含酚条件下,易鼓泡硬化,达不到应有的效果。没有改性的双马来酰亚胺由于双键间距短,其固化交联密度高而脆性大,难溶解,工艺窗口窄,不能单独用于制备防腐涂料。因此,亟需研究新型的抗冲刷腐蚀涂层。而面对腐蚀穿孔而造成的石油污染,微生物降解技术因其成本低廉、原位性和无二次污染,得到越来越广泛应用。协同作用是有机污染物的微生物降解研究的重点。本论文用失重法、电化学法和表面分析等方法研究了金属在流动和含砂的腐蚀介质中的腐蚀行为和缓蚀剂抑制效果以及缓蚀剂现场应用过程中的室内综合评价方法;用IR, DSC, TGA, ESEM等方法研究了BMI/1,3-PBO/油酸三元共聚对提高双马来酰亚胺(BMI)的工艺性、韧性和耐热性的影响;用摩擦磨损、剪切强度和多相流冲刷等试验对环氧树脂/改性双马来酰亚胺胶粘涂料的性能进行了研究;利用自建的气相色谱与紫外分光光度法联合评价微生物对柴油降解过程的方法,分别研究了分支杆菌和枝孢属菌对柴油的降解以及两种微生物之间的协同作用。旨在探讨缓蚀剂在含砂的高流速腐蚀介质中的腐蚀抑制和室内评价方法的建立,极端腐蚀条件下改性环氧涂料的性能,以及柴油的微生物处理过程中细菌的协同作用机理,为管道系统的内腐蚀防护应用和石油烃处理提供理论依据和技术支持。主要研究结果如下:腐蚀介质中临界流速为3～4m/s。在不同流速下,介质中砂的存在明显促进了腐蚀。同一种缓蚀剂不同浓度下其临界流动强度有所不同。腐蚀介质流速为1m/s和3m/s时,缓蚀剂的极值浓度为120mg/L,流速为4m/s和5m/s时缓蚀剂的极值浓度增加为160mg/L,而流速为7m/s时缓蚀剂的极值浓度为200mg/L。极值浓度随砂的加入而进一步升高。当缓蚀剂浓度为120mg/L时其临界流速大约为3m/s,缓蚀剂浓度为200mg/L和280mg/L时其临界流速大约为3.5m/s和4.5m/s。在流速7m/s的含砂体系中,即使浓度高达280mg/L的缓蚀剂也无法有效控制腐蚀速率。通过对混合抑制型缓蚀剂与在用缓蚀剂的静态腐蚀评价、高压动态评价和电化学测试等性能评价,本文发现,缓蚀剂投加量为30mg/L时的腐蚀速率控制达到了在用药剂效果;缓蚀剂具有乳化倾向小、起泡倾向小、与在用阻垢剂和破乳剂配伍性较好等特点,同时具有一定的协同效应;现场腐蚀挂片结果表明,该药剂比较适合番禺油田油水介质和工况条件,能满足现场腐蚀防护的需要。现场应用的实践表明了应用不同评价手段的一致性原则发展起来的缓蚀剂室内综合研究方法的有效性和适用性。利用BMI和噁唑啉的反应将柔性链导入BMI体系,并且油酸具有长的柔性链和反应基团(碳碳双键和羧基),能与BMI和1,3-PBO发生共聚反应。BMI,1,3-PBO和油酸的三元共聚能提高BMI聚合物的工艺性和韧性,并且保持一定的耐热性。试验结果表明,1,3-PBO和油酸在低温时对BMI树脂起到稀释作用,在高温时,BMI、1,3-PBO、油酸之间的共聚反应增加了固化物的交联密度,固化树脂保持高的玻璃化转变温度。SEM表面形貌观察结果证实1,3-PBO、油酸能增韧BMI树脂,主要由于形成了酯-酰胺键和油酸长的脂肪链。从环氧和改性环氧三种涂层在不同介质存在的条件下拉伸剪切强度的数据变化可知,除了BMI-B/EP涂层在碱性条件下性能较差外,其在其它情况下的耐介质性能是最好的。研制的改性双马来酰亚胺/环氧基粘接膜在室温至120℃范围内具有优良的摩擦学性能。经高温多相流冲刷试验,改性后的环氧树脂涂层耐高温冲刷效果优于环氧涂层。当分支杆菌菌株和枝孢属菌株混合使用时,柴油在五天后的生物降解率高达80%;通过分支杆菌菌株和枝孢属菌株的协同降解作用可完全除去水体中的柴油污染物;协同作用主要涉及到枝孢属菌株对芳香烃的降解而促进了分支杆菌菌株的生长。更多还原

【Abstract】 Equipment corrosion and environmental pollution caused by leaked crude oil are two main problems in oilfields. 3% NaCl solution was commonly used to investigate CO2 corrosion as simulation medium under static and lower flowing conditions, which was different from on-site corrosive medium at high flow velocity under multiphase containing sand in oilfields. Under those conditions, corrosion inhibitor could not perform effectively and protective coating of anti-erosion wearing and corrosion resistance is widely used to control corrosion. Epoxy resin coating was used to protect erosion wearing inside equipment, which was easy to bubble, harden and lost its performance under high temperature and medium containing hydroxybenzene. However, unmodified bismaleimide (BMI) resins could not be solely used for anti-corrosion coating because of their high crosslinking densities after curing, poor solubility, and narrow processing window; and therefore a new type of anti-erosion wearing coating is anticipated to research. For the increasingly serious petroleum pollute, the biodegradation technology was used more widely because of the advantage of low cost, in-situ degradation and no pollution products. Synergic effect is always the important spot of research in the field of biodegradation of organic pollutants.In this dissertation, corrosive behavior of carbon steel under flowing condition and corrosive solution containing sand, corrosion inhibitor’s inhibition performance, and lab comprehensive evaluation of corrosion inhibitor, were investigated by weigh lost method, electrochemical techniques (electrochemical impedance spectroscopy (EIS), linear polarization resistance), surface analysis(scanning electron microscope (SEM), X-ray diffraction (XRD)), etc; by ternary copolymerization of BMI, 1,3-PBO and oleic acid, the curing behavior and some properties of the processibility, toughness and heat resistance were focused on by IR, DSC, TGA, ESEM, etc; properties of adhesive coating of modified epoxy resin with BMI were investigated by friction wear, shear strength, multiphase erosion-wearing testing; by combination of the two analytical techniques, gas chromatography and UV spectrophotometry to evaluate the microorganisms biodegradation of diesel, the biodegradation process of diesel by bacteria Mycobacterium hyalinum (MH) , by fungi Cladosporium, and their synergic effect were studied, respectively. Our aims are to discuss inhibition performance of corrosion inhibitor under high flowing corrosive solution containing sand, establishment lab comprehensive evaluation method and properties of modified coatings under extreme corrosive conditions, mechanism of synergic effect of biodegradation of diesel, which can provide academic explanation and technical support for protection of inner corrosion in pipeline systems and the bioremedy of leaked crude oil. The main conclusions are as follow:Critical flow velocity in uninhibited corrosive solution is between 3m/s and 4m/s at testing conditions. At different flow velocity, corrosion rate is further increased by the entrained sand in the medium. Corrosion inhibitor shows the peak-value-phenomenon in corrosive solution under flowing condition. The optimum concentration is 120mg/L as the flow velocity is less than 3m/s, in contrast with the concentration of 160mg/L when flow velocity is between 4m/s and 5m/s and the concentration of 200mg/L when flow velocity is 7m/s. The optimum concentration is further increased when adding sand. Critical flow velocity is different in inhibited corrosive solution at different concentration. Critical flow velocities are 3m/s, 3.5m/s, 4.5m/s in inhibited corrosive solution at the concentration of 120mg/l, 200mg/l and 280mg/l, respectively. Corrosion rate of medium containing sand at the flow velocity of 7m/s could not effectively controlled by corrosion inhibitor with the concentration of 280mg/l or higher.Compared mixed corroison inhibitor with incumbent corrosion inhibitor by static coupon testing, dynamic high pressure coupon testing, electrochemical techniques, compatability test with incumbent scale inhibitor and demulsifier, and on-site application, all the results have demonstrated that this corrosion inhibitor is a mixed type of absorptive inhibitor, which can effectively inhibit locale corrosion with characteristics of low emulsification and better compatability, and also meet anti-corrosion’s requirements. On-site monitoring results show that lab comprehensive evaluation is effective and applicable to settle the discrepancy of lab screening on corrosion inhibitor.By spontaneous reaction between BMI and oxazoline, flexible linkage or chain was introduced into BMI. Oleic acid, which presents long flexible chain and reactive groups (C=C double bond and -COOH), was copolymerized with BMI and 1,3-PBO. By ternary copolymerization of BMI, 1,3-PBO and oleic acid , the processibility and toughness of BMI was improved while keeping their good heat resistance. The results indicates that 1,3-PBO and oleic acid play a role in diluting to BMI at lower temperatures. At higher temperatures, the copolymerization between BMI, oleic acid and 1,3-PBO increases the crosslinking density in the resultant materials. The cured resin still remains high Tg. SEM results confirm that 1,3-PBO and oleic acid could toughen BMI system because of the formation of ester-amide bonds and the long fat chain of oleic acid. By testing tensile-shear strength of epoxy resin coatings at different corrosive media, it gains that BMI-B/EP has the best performance under different conditions except in alkaline medium. Modified epoxy adhesive resins show fine friction property at temperature range from 20℃to 120℃. Testing results under conditions of multiphase corrosive media and high flow velocity at high temperature show that modified epoxy coatings exhibited excellent performances of erosion resistance and high wear resistance than epoxy resin coating.When the mixture of bacteria strain MH and fungi strain Cladosporium is used, the extent of diesel biodegradation is significantly increased by 80% after five days; Diesel pollutants in aqueous solution can be completely removed by synergistic use of these MH and Cladosporium; The observed synergistic effect is closely related to the aromatics-resistance of the fungi strain Cladosporium, which in turn favors the growth of the MH.更多还原