Synthesis And Properties Of Fluorinated Polyether

At present,many offshore oil fields in China have entered the late stage of oil field exploitation.In order to meet the daily needs of stable production and increase production of oil fields and meet the daily needs of national life,polymer flooding technology has been widely used for this purpose.Polymer flooding technology,while satisfying the enhanced oil recovery,also allows polymer to enter the crude oil emulsion,interact with the natural active substances in the crude oil components,make the crude oil emulsion more stable,increase the difficulty of subsequent emulsion breaking and dehydration,and the space of the offshore platform is small,which is not conducive to large-scale storage of the crude oil emulsion produced,and the existing demulsifier is in the prescribed conditions.It is difficult to meet the requirements,so it is necessary to explore and develop new demulsifiers or similar demulsification methods to meet the demulsification and dehydration requirements of offshore platforms under the current conditions.Due to its high surface activity,high thermal mechanical and chemical stability,fluorine-containing surfactants have important applications in many fields.In this paper,bisphenol AF and bisphenol AF phenol amine resin are selected as polyether initiators to synthesize a series of fluorine-containing polyether surfactants through the polymerization process with reliable and mature Ethylene Oxide(EO)and Propylene Oxide(PO).The purpose of this paper is to explore the introduction of fluorine into the molecular structure of demulsifiers and whether the series of fluorine-containing demulsifiers have good demulsification and dehydration effect on offshore crude oil.Therefore,the research content of this paper is divided into the following three aspects:1.Bisphenol AF,catalyst potassium hydroxide and solvent xylene were directly put into a high-pressure reactor.Under the catalysis of Potassium hydroxide,bisphenol AF was polymerized with propylene oxide to form a hydrophobic section,and then the hydrophilic ethylene oxide section was polymerized to form a fluorine-containing linear block polyether surfactant.Then the structure of the surfactant was characterized by NMR and IR spectrum.The effects of different types of salts on the cloud point,surface activity,interfacial activity and particle size of the surfactant were studied.Turbidity test shows that different kinds of salts play an important role in the cloud point of polyether.Salting out salt reduces the cloud point of polyether,while salt dissolving salt is the opposite.The surface tension of surfactant in pure water,different salt solutions and different temperatures is studied by using surface tension meter.It is found that the surfactant of this system has a good ability to reduce the surface tension in pure water.When the concentration of surfactant is low,salt has obvious effect on surfactant.When the concentration of surfactant reaches the critical micelle concentration(CMC),the effect of salt is very little.Two organic solvents,toluene and n-heptane,are selected to interact with the aqueous solutions of the series of surfactants with different concentrations.The interfacial tension of the series of surfactants in the two oil-water systems is studied.It is found that the series of surfactants are active Among them,z9937 has a stronger ability to reduce the interfacial tension.2.Using bisphenol AF,formaldehyde solution and tetraethylene pentamine,bisphenol AF phenolic amine resin was synthesized by two steps as the starting agent of demulsifier.A total of 15 demulsifiers were synthesized and named BPAF demulsifier according to the mass ratio of initiator to PO,PO/EO.The structure of the demulsifier was characterized by NMR and IR spectrum.The results showed that the synthesis of the demulsifier was good.The demulsification test shows that for K oil,3.7:1 demulsifier is the optimum proportion,and three demulsifiers Bisphenol AF 9937,13937 and 16937 are selected.The results show that the ratio of 3.7:1 is better than other ratios,which is consistent with the demulsification results.The cloud point test shows that the PEO segment content in the demulsifier molecule has an important influence on the demulsifier cloud point.In the demulsifier molecule,the PO/EO remains unchanged,the demulsifier molecular chain increases,and the demulsifier cloud point decreases The test of the molecular weight of demulsifier shows that the molecular weight of demulsifier has no direct influence on the demulsification results.For K oil,a good demulsifier is a high molecular demulsifier,but the high molecular demulsifier does not necessarily have a good demulsification effect.3.The results show that the demulsification effect of multi branched demulsifier is better than that of linear straight chain demulsifier,so we choose the straight chain and multi branched polyether to be cross-linked with different amounts of polyphenyl ring polyisocyanate pm200,and explore the cross-linking modification of straight chain polyether with cross-linking agent,and compare with the original multi branched polyether and cross-linking agent after further cross-linking modification The results showed that under the same PO/EO ratio,the polyether with straight chain and cross-linked had no demulsification,and the multi branched polyether with phenol amine resin as starting agent had good demulsification effect.The demulsification result after cross-linking modification was further improved.The multi branched polyether before and after modification was tested for instability.The results showed that the higher the water content of crude oil,the higher the demulsification temperature and the more demulsifier was added The results show that when the water phase contains AP-P4,the oil droplets are more difficult to combine with oil,indicating that the presence of polymers makes the oil-water interface more stable.The addition of demulsifier makes the oil droplet speed faster than that of oil.With the increase of demulsifier concentration,the binding rate first increases and then slows down,indicating demulsification.The amount of demulsifier should be suitable.The demulsifier after modification is more favorable for the combination of oil drop and oil.