Study On Preparation And Properties Of Grafted Modified Fluorine Silicon Crude Oil Demulsifier

As the development of science and technology, crude oil play an increasingly important role in the politic and economy. So many measures have been taken to improve the oil recovery. Thus the oil become more and more stable, which brings great difficulties to demulsification. At present, many people are devoted to studing the polyether modified silicone oil emulsion breaking. However, few scholars have studied the long chain alkyl acrylate and fluorinated monomer into polyether modified silicone oil, moreover studied its solution properties and performance. This thesis based on the difficulty of crude oil demulsification, preparing a clean and efficient system for a variety of crude oil demulsifier.Two amphiphilic grafted nonionic surfactants(PEH, PES) were synthesized, which used polyether as hydrophilic monomer, hydrogen silicone(PHMS) and long chain alkyl (acrylic sixteen ester and acrylic eighteen ester) as hydrophobic monome in the temperature of 95℃ and reaction time of 7h. The structure of polymers was characterized via infrared spectroscopy(FT-IR) and nuclear magnetic resonance hydrogen spectrum(1H-NMR); the micelle size and distribution in solution were discussed; the effect of hydrophobic content on the surfactant minimum surface tension(γCMC) and critical micelle concentration (CMC) was analysised; the adsorption behavior of surfactant on the air/water interface and the aggregation behavior of surfactant in aqueous solution were discussed. The results showed that the reaction obtained expected product; the average particle size of polymer PEH was increased from 100.5 nm to 242.9 nm, the average particle size of polymer PES was increased from 152.6 nm to 329.1 nm, and the particle size dispersion coefficient increased with the increase of long chain alkyl esters. PEH and PES polymers γcmc and CMC were decreased first and then increased, which PEH4 γCMC reached to the lowest 22.08 mN/m, and CMC reached to 0.458 g/L, PES3 γcmc and CMC reached to 21.84 mN/m and 0.447 g/L; PEH and PES solution surface molecular adsorption(F) increased first and then decreased, the average area of adsorption(A) showed the opposite trend; PEH and PES critical association concentration (CAC) was the same as CMC.Then synthesized a series of polyether, perfluoro butyl ethyl acrylate (TEAc-4) modified silicone surface active agent (PEFB) and polyether, perfluorinated ethylhexyl acrylate(TEAc-6) modified silicone surface active agent(PEFH). The properties of the polymer were analyzed by means of above characterization methods. The results showed that the reaction obtained expected product.polymer average particle diameter increased with the increase of fluorinated monomer. The average particle size of PEFB was increased from 71.2 nm to 282.5 nm, and PEFH increased from 63.86 nm to 162.2 nm. The PEFBand PEFH polymer γcmc and CMC decreased first and then increased with the increase of fluorine-containing monomers, which PEFB3 CMC and γcmc reached the lowest 0.373 g/L and 21.40 mN/m, PEFH3 reached the lowest CMC and γCMC 21.26 mN/m and 0.355 g/L; The polymer solution surface molecular adsorption(Γ) increased first and then decreased, and the average area of adsorption(A) showed the opposite trend; The changing trend of CAC was similar to CMC. After modified by fluorine, the polymer has a higher surface activity.In the end, the above series of surfacant were used as crude oil demulsification and the demulsification effect of Hezhuangping and Dingbian crude emulsion was discussed by bottle test method, and then evaluating the demulsification effect of compound demulsifier concentration, temperature, pH value and salinity. The results showed that the polymer had certain demulsification for crude oil. The demulsification rate of PEFB3 for two kinds crude oil up to 62% and 56%. The demulsification rate of compounded demulsifier was improvedsignificantly, Hezhuangping crude oil demulsification rate reached 85%, and Dingbian crude oil demulsification rate reached 83% when PEFB2:L61=2:1; three compound demulsifier PEFB2-L61-M (PEFB2:L61:M=4:2:1) demulsification rate can reach 98% and 95% separately. Finally, the performance of PEFB2-L61-M demulsifier was evaluated, whose demulsifier had good demulsification, a certain acid and alkali, salt tolerance, and good broad applicability.