Study On Preparation And Demulsification Of Cationic Reverse Demulsifier

Polymer flooding has been widely applied in the Bohai Oilfield,however,the stability of produced liquid dramatically increased due to the existence of polymer.It is difficult to achieve efficiently breaking the emulsion under the action of demulsifier.So,there is necessary to design a new agent,in order to ensure that the demulsifier is still used under low dosage,which could be combined with demulsifier to break the stable emulsion,ie,reverse demulsifer.In this parper,a series of reverse demulsifiers were synthesized and their demulsifying properties were evaluted.The main work is as follows.1.A multi-branched reverse demulsifier was synthesized with the core of BPA phenolamine resin,the branch of different PEO block proportions?BPAEO10,BPAEO40?and the terminal quaternary ammonium salt,which was applied to study the oily wastewater.By the orthogonal test,the optimal synthesis process of BPA phenol amine resin was obtained.The chemical structure of the reverse demulsifier was confirmed by multiple methods,such as 1H NMR,FT-IR spectra and the determination of OH group.By studying the surface activity of the reverse demulsifier,it was found that the performance of samples would be better with the increase of the graft amount of quaternary ammonium salt,which would lead to larger cmc,and higher surface activity.The oil removal efficiency of B10C1660 was found to be 97.8%by standard evaluation methods2.A multi-branched,organic ammonium salt polyamides was synthesized with the nonylphenol?NP?as core using different organic acids as neutralized agent.The chemical structure of NP reverse demulsifier was confirmed by multiple methods,such as lH NMR,FT-IR spectra and elemental analysis.To studying the demulsification of the crude oil emulsion,the polyamide demulsifier was compounded with demulsifier A,which was made at laboratory.It was founded that the colloid was more stable when the agent was added to oily wastewater,the interfacial tension of oil-water interface was least,the better performance.The oil content in the water of dehydration was 1843 mg/L,and the dehydration rate of crude oil emulsion was above 80%,when the NP-3?200 mg/L?ammonium salt using butyric acid and hexanoic acid was mixed with demulsifier A?100 mg/L?added to crude oil emulsion in the laboratory.The effect was better than the platform agent CC351.3.Organic-inorganic hybrid cationic reverse demulsifier PNAD was synthesized by the copolymerization of the modified Nano-SiO2 monomer and hydrophilic monomers.Organic cationic linear reverse demulsifier PAD was synthesized using the hydrophilic monomers.The chemical structure of PNAD/PAD reverse demulsifier was confirmed by multiple methods,such as 1H NMR,FT-IR spectra and cation degree.The results showed that the difference of the PNAD/PAD structures leaded to the higher charge density of PNAD.According to Zeta potenial,oil floc-strength factor?Sf?and oil floc-recovery factor?Rf?,oil-water interfacial tension,it was found that the stablity of colloid of PAD agent was poor than the PNAD reverse demulsifier,the higher Sf and small Rf and lower interfacial tension.The dehydration rate of crude oil emulsion was above 90%,and the oil content of the water was as low as 1472 mg/L when the dosage of PNAD₃ reverse demulsifier was 250 mg/L and A was 100 mg/L,but the same result would be achieved when the PAD-1 was 1350 mg/L.The effect of compouned agent was obviously better than of the two agents alone.4.The PAD was selected for amplificating process study using 10 L reactor,exploring the effect of the molecular weight regulators and composite initiators for the polymerization process.The viscosity and Mw of the amplified product were measured by HAAKE rheometer and SEC-MALS respectively,the results showed that the viscosity and Mw decreased over the amount of chain transfer increasing.PAD-5 synthesis process was selected,the dehydration rate of crude oil was 98%,the oil content in water was 1687 mg/L,and the water content in oil was 12971.5 mg/L,when the dosage of PAD-5 was 70 mg/L and A was 100 mg/L.