Controlled Fabrication Of Magnetic Composite Particles And Their Performance Of Oil-water Separation

Crude oil and water emulsions occur in the different stages of crude petroleum operations.The first step in oil and gas production operation is to separate and treat the water and other impurities i.e.,sand and sludge from crude oil in order to meet the refinery demands.Because of the great importance of this field,a few scientific studies have been conducted so far.Due to the variation in the physical properties of crude oils there are some difficulties associated with the characterization,emulsion formation and measurement of the demulsification process of crude oil/water emulsions.So there are many difficulties to develop a general demulsifier.If the emulsified water is not removed from the crude oil,it will lead to the quality problems and economical losses.Based on this,different types of interfacially active and magnetically responsive magnetic composite microspheres with Janus,raspberry and core-shell like morphologies were designed and synthesized by novel synthetic ways to address their applications as affective demulsifiers.Also the effects of the holdup,settling time,temperature,mixing conditions,the concentration of the novel magnetic composite microspheres as demulsifiers and types of crude oils characterized by the concentration of the waxes on the separation were experimentally investigated.The experimental separation process is successfully used to verify the theoretical idea developed based on droplet coalescence,interfacial properties and magnetic response.Iron oxide@poly?Glycidyl methacrylate-methyl methacrylate-divinyl benzene??Fe₃O₄@P?GMA-MMA-DVB??magnetic composite microspheres with proper core-shell like morphology were prepared by solvothermal process,followed by precipitation polymerization method.Then the surface epoxy group of Fe₃O₄@P?GMA-MMA-DVB?was modified with an amino group on reaction with ethylene diamine?EDA?to prepare Fe₃O₄@P?GMA-MMA-DVB?/NH2 magnetic composite core-shell microspheres.Also the surface morphology and properties of Fe₃O₄@P?GMA-MMA-DVB?/NH2 were characterized using laser particle size analyzer,transmission electron microscopy,fourier transform infrared spectroscopy,vibrating sample magnetometry and thermogravimetric analyzer.The synthesized core-shell microspheres showed paramagnetic properties with a saturation magnetization value about 19 emu/g.Experimental results showed that Fe₃O₄@P?GMA-MMA-DVB?/NH2 can separate heavy oil /water emulsion in 9 h with 1000 ppm concentration at 80 oC.Also Fe₃O₄@P?GMA-MMA-DVB?/NH2 can be recycled for four times by magnetic separation.Fe₃O₄ magnetite nanoparticles were first synthesized by solvothermal process,which were then encapsulated in poly?methylmethacrylate-acrylicacid-divinylebenzene?to form magnetic composite microspheres?Fe₃O₄@P?MMA-AA-DVB??by precipitation polymerization method with proper core-shell structure.Using laser particle size analyzer,transmission electron microscopy,fourier transform infrared spectroscopy,vibrating sample magnetometry,and thermo gravimetric analyzer,the surface morphology and magnetic properties of the magnetic composite core-shell microspheres were characterized.The synthesized core shell microspheres show the characteristic of paramagnetic with the saturation magnetization value of about 29.8 emu/g.There are carboxylic groups on the interfacially active P?MMA-AA-DVB?walls,which show better demulsification properties.Experimental results show that 800 ppm of Fe₃O₄@P?MMA-AA-DVB?can separate heavy oil/water emulsion in 6 h at 80 oC.Due to strong magnetic properties,Fe₃O₄@P?MMA-AA-DVB?can be recycled five times by magnetic separation.Poly?methylmethacrylate-acrylicacid-divinylbenzene?/Iron oxide?P?MMA-AA-DVB?/Fe₃O₄?magnetic composite microspheres were designed and prepared with Janus and raspberry like surface morphology,strong magnetic domains and unique surface functionalities.The P?MMA-AA-DVB?microspheres were prepared via soap-free emulsion polymerization and used as a precursor for preparing Janus and raspberry like composite microspheres via solvothermal process.The morphology and magnetic properties of both the magnetic composite microspheres were characterized using laser particle size analyzer,transmission electron microscopy,fourier transform infrared spectroscopy,vibrating sample magnetometer,and thermogravimetric analysis.The particle size,magnetic content and the saturation magnetization of P?MMA-AA-DVB?/Fe₃O₄ magnetic Janus microspheres were 220 nm,40%,and 20 emu/g,and that for raspberry type they are 250 nm,45 % and 25 emu/g respectively.The formation mechanisms of both Janus and raspberry microspheres were also investigated,and the results reveals that the reduction of Fe3+ ions and growth of Fe₃O₄ nanoparticles take place on the surface of P?MMA-AA-DVB?polymeric precursor particles.The magnetic part of both Janus and raspberry like magnetic composite microspheres at the oil/water interface make the interfacial properties tunable and responsive to an external magnetic field.The interfacial activity of P?MMA-AA-DVB?/Fe₃O₄ magnetic composite microspheres with raspberry like structure allow them to be effectively attached to stable emulsified water in heavy crude oil/water emulsion and readily remove them by an external magnetic,under optimized conditions,which is 600 ppm and 2 h for Janus type and 400 ppm and 1 h for raspberry type microspheres at 60 oC.It is found that external magnetic field enhances the coalescence of magnetically tagged water droplets in an emulsion.The magnetic property of raspberry like P?MMA-AA-DVB?/Fe₃O₄ magnetic composite microspheres allows the used microspheres to be readily recycled by magnetic separation and solvent washing.The recycled raspberry like P?MMA-AA-DVB?/Fe₃O₄ is found to retain its surface morphology,interfacial activity,magnetic response and effective in breaking the heavy crude oil water emulsion.The adsorption of raspberry like P?MMA-AA-DVB?/Fe₃O₄ magnetic composite microspheres at the oil/water interface with their magnetic properties demonstrating enhanced coalescence of magnetically tagged water droplets and their rapid separation from the emulsions by an external magnetic field.Here we can conclude that the synthesized raspberry like and Janus P?MMA-AA-DVB?/Fe₃O₄ magnetic composite microspheres are anticipated to give a new pathway for oil-water separation in the petroleum industry.