The Synthesis Of Fluorocarbon Imidazoline Quaternary Ammonium Salt And Applied Research Of Its In Oil Well For Incorrison

Produced fluid of oil wells contain mass corrosive medium to cause severe corrosion to equipment in the crude oil mining, collecting, transportation, refining. That resulted in economic losses and environmental pollution. Seeking to effectively technology which prevents the produced fluid into corrosion of equipment has become important and difficult to ensure the normal oil production. This paper was focus on, by studied oilfield corrosion mechanism of produced fluid, synthesis of fluorocarbon imidazoline quaternary ammonium salt with multi-functional, efficient, low toxicity. As the main agent in corrosion inhibitor, it compounds other additives form a highly efficient oilfield produced water corrosion inhibitor, which can control effectively, comprehensively, systematic suppression the corrosion of the corrosive medium in produced fluid to equipment in the extraction, collection, transportation, refining of the crude oil.1. Based on the analysis of corrosion mechanism of corrosive elements to metal equipment contained in the oil produced liquid was studied. Mass mineral salts and O2, CO2, SO42-, Ca2+,Mg2+,Cl-, HCO3-,H2S, SRB (sulfate reducing bacteria) and other corrosive medium dissolved in water of produced fluid corroded metal equipment. Corrosion mechanism was cross-corrosion which involved in electrochemical corrosion caused by mineral ions, and bacteria microorganisms’corrosion, and mechanical stress corrosion.2. By this corrosion mechanism, the targeted inhibitors were the choice to suppress the corrosion of equipment from the produced fluid. And by anti-corrosion mechanism of inhibitor, fluorocarbon imidazoline quaternary ammonium salt compounds, as the main agent for the inhibitor, were designed. In this paper, the synthesis of the mechanism of proton catalytic synthesis and compound characterization were studied. The results showed that fluorocarbon imidazoline was synthesized with B amine and perfluorooctanoic A acid as the raw material, and mesoporous Al2O3Y supporting HPW as catalyst, reacted for9h in130℃. The yield of the reaction was up to96%. Fluorocarbon imidazoline quaternary ammonium salt was successfully synthesized in the reaction after10hours, and the temperature controlled at90-100℃, mole ratio of fluorocarbon imidazoline and alkylating agent were1:1, the yield was84.6%. The compounds were characterized by IR, GC/MS, NMR spectra, and molecular weight was481, that consisted completely with the theory.3. In this paper, the synthesis of mesoporous Al2O3Y supported HPW catalyst in preparation of imidazoline was studied. It prepared by homogeneous precipitation with urea as precipitation agent, SDS as template. The product specific surface area was627.43m2/g, and had narrow pore size distribution (concentrated around5nm), and pore size distribution, and regular shape.4. The fluorocarbon imidazoline has maximum absorption of UV wavelength at235nm.the content of fluorocarbon imidazoline tested by UV was studied Using this feature. There were a good linear relationship between the absorbance of fluorocarbon imidazoline and its concentration range of0.005-0.030mg/mL.The linear correlation coefficient R20.99882. The average recovery was99.72%, relative standard deviation (RSD) was0.8to2.0%, and this test means production can be used for quality controlling in production.5. Fluorocarbon imidazoline quaternary ammonium salt is a new compound, its physical and chemical properties were studied. The compound was heated up to220℃, the first open chain decomposition was beginning, and degraded completely at400℃. It showed that it has higher thermal stability. With it’s dosage in water be0.05%, the surface tension of water could fall to22.04from81.6mN/m. The CMC of is100mg/l. The fluorocarbon imidazoline quaternary ammonium salt was placed in sulfuric acid, and mixture solution (98%sulfuric acid/chromium oxide=100/l), and alkaline (NaOH saturated aqueous solution) for10days. There were no changes in surface tension, which indicated the compound has a strong chemical stability.6. Fluorocarbon imidazoline quaternary ammonium salt was fine bactericide for sulfate-reducing bacteria. It was compared with1227, isothiazolin ketone, hydrocarbon imidazoline quaternary ammonium salt in sterilization performance, the bactericidal efficiency of compound was the highest. When its dosage was30mg/l, all of sulfate-reducing bacteria could be killed.The sterilization rate reached100%. After Wistar rats trail oral acute toxicity test in Whitethorn’s methods showed that the LD50of fluorocarbon imidazoline quaternary ammonium salt was1046.41mg/kg, and the compound is low toxicity grade.7. The inhibition mechanism of fluorocarbon imidazoline quaternary ammonium salt was discussed in this paper. Because the molecular structure of the compound contains primary N, secondary N, tertiary N, quaternary N and fluorocarbon hydrophobic group, and the benzene ring in benzyl group, that groups made not only the coordination bonds with metal, but also provided the proton to make the adsorption complex with metal surface stronger than the coordination bond. Adsorption mechanism of fluorocarbon imidazoline quaternary ammonium salt meets with all of the adsorption mechanism of organic adsorption inhibitor. The fluorocarbon hydrophobic with low surface tension was more effectively than ordinary paraffin medium reach to the metal surface to prevent corrosion. When its dosage was1/600of general inhibitor, the corrosion inhibition rate increased to91.2%from64.4%. This indicated it had very high inhibition efficient.8. By the standard addition method, affects on determination of iron content using Phenanthroline spectrophotometer method was anglicized from oil, water hardness, demulsifies and other factors in oil field waste water. The results showed that oil content of produced water had great effect on the accuracy of test of this method. Oil could affect seriously on the light transmittance. While the demulsifier, water hardness, oil field waste water had little effect on the determination of iron content.9. Fluorocarbon imidazoline quaternary ammonium salt corrosion inhibitor for corrosion of underground equipment was judged by oil field application test. The results showed that the total iron content in the liquid effluent decreased in dosing wells, the average decline rate of64.39%～76.80%than in the blank wells; weight loss results showed that the corrosion inhibition rate were beyond97%in three dosing wells. The application test ensured that the special use of high efficient inhibitors can inhibit corrosion of the oil recovery equipment, and certified the use of inhibitors to suppress the liquid corrosion on the oil recovery equipment was an effective anti-corrosion process.