Study On The Preparation Of Biomass-based Demulsifier And Its Demulsification Performance

The formation of crude oil emulsion is a common problem faced by most countries in the world during the production stage of petroleum industry.Crude oil emulsions are mainly formed during oil extraction and transportation.The presence of water in crude oil emulsions not only increases the cost of oil processing and transportation,but also causes corrosion of equipment during oil extraction and transportation.So far,a variety of induced phase separation techniques have been developed in the petroleum industry,among which chemical demulsification is one of the most widely used technology.Biomass-based demulsifiers have been widely concerned because of its green and low cost advantages,so it is of great significance to carry out research on biomass-based demulsifiers.In this paper,three types of biomass-based demulsifiers were prepared according to the characteristics of different types of crude oil emulsions,and their demulsification performance and related demulsification mechanism were studied.The main contents are as follows:Taking into account the natural Janus material properties of lotus leaves and the micro/nano structure of their surface,an environmentally friendly biomass demulsifier（LLP@Si O₂）was prepared by simple hydrothermal method by coating nano-Si O₂ on natural lotus leaves powder.Fourier-transform infrared spectroscope（FT-IR）,field-emission scanning electron microscope（FE-SEM）,energy dispersive X-ray spectroscope（EDS）and thermal gravimetric analyzer（TGA）were employed to characterize the demulsifier.The effect of the LLP@Si O₂ dosage,temperature,settling time,p H value and salt concentration on the demulsifying process was studied in detail.The bottle test results showed that the demulsification efficiency（DE）reached 83.78%within 1 min when the dosage was 600 mg/L at 70℃.The DE could increase to 91.91%if the settling time was prolonged to 60 min.The LLP@Si O₂ demulsifier had excelent acid and salt tolerance,and the high salinity also could improve the demulsification performance.It showed that the DE could maintain at 91.91%even at strong acid condition of p H=2 and it increased to 94.33%when the salinity was increased to 20000 mg/L.In addition,the possible demulsification mechanism was systematically studied by the interfacial activity,interfacial tension,wettability and microexamination.Due to the rice straw（RS）is a biological waste rich in silica,a biodegradable,low-cost and environmentally friendly biomass demulsifier（A-RS）was prepared using RS via a simple acid treatment process.It was characterized by field emission scanning electron microscopy（FE-SEM）,energy dispersive X-ray spectrometer（EDS）,Fourier transform infrared spectroscopy（FT-IR）and thermogravimetric analysis（TGA）.The influence of demulsifier dosage,temperature,settling time,p H value and salinity on the demulsification efficiency（DE）of water-in-crude oil emulsion were explored through bottle tests.The results displayed that the DE could reach 89.52%within one minute when the dosage of A-RS was 600 mg/L at 70℃.The A-RS demulsifier had a good acid and alkali resistance,the DE could reach 92.72%and 86.32%when the p H value of emulsion was 2 and 10,respectively.Also,it had an excellent salt tolerance,and the DE increased slightly with the increase of the salinity.The demulsification mechanism was also investigated through interfacial activity,interfacial tension（IFT）,wettability,formation of interfacial film and optimal microscopy.For the reduction of raw material costs,biodegradable environmental protection and waste reuse,diethylenetriamine was used to modify rice straw powder（RSP）by a solvent-free strategy,and the obtained product（AM-RSP）was utilized to dispose oily wastewater.AM-RSP was characterized by Field emission scanning electron microscope（FE-SEM）,energy dispersive spectrometer（EDS）,Fourier transform infrared spectroscope（FT-IR）and BET.The factors affecting the demulsification performance（DP）such as dosage,salinity and p H value were detailly investigated.The results indicated that light transmittance（ET）and oil removal rate（ER）of separated water could reach 93.5%and96.5%,respectively,within 40 min with 150 mg/L of AM-RSP at room temperature.Also,AM-RSP had a good salt resistance.In addition,three-phase contact angle（TCA）,formation of interfacial film,interfacial activity,dynamic interfacial tension（IFT）,coalescence time of droplets and Zeta potential were adopted to probe the demulsification mechanism.