Preparation And Study On Properties Of Demulsifier Polyether Grafted On ZIFs

As an important oil recovery technology,ASP flooding has been gradually applied in many oilfields in recent years.However,with the application and promotion,the problems generated can not be ignored.The water produced by the ASP flooding has complex composition and high salinity,which also has the characteristics of high content of fine oil droplets,high emulsification,high viscosity,high strength and low tension of oil-water interfacial film.The produced water system of ASP flooding is difficult to demulsify and oil-water separation because of its stable phase state.In that case,the produced water without demulsification and oil removal can not meet the requirements of reinjection or discharge,which limits the further promotion of ASP flooding technology.In this paper,a reverse demulsifier polyether grafted ZIF-8 was synthesized according to the characteristics of produced water from ASP flooding.The demulsification and oil removal of produced water was completed by the synergistic effect of demulsification and adsorption.The polyether has the characteristics of low surface tension,good chemical stability and strong surface activity.While its carboxyl and ester groups on the side chain make the demulsifier have better dispersing and wetting performance.In addition,compared with linear demulsifiers,polyethers with a multi-branched structure have better permeability and wettability.Therefore,the polyether has more remarkable demulsifying effect.ZIF-8 is a kind of zeolites imidazole ester skeleton material,which has high porosity,high physical,chemical and thermal stability.ZIF-8 is intended to be used as adsorbent to complete the adsorption.In addition,the presence of organic ligands in ZIF-8 provides the possibility to introduce a variety of functional groups,which can be improved or introduced by modifying the ligands.The main research contents of this project include three parts:In the first part,based on the water quality analysis of the produced water samples from Shengli Oilfield,the simulated produced water from ASP flooding was prepared for future use.VT550 viscometer,VHX-6000 high magnification large depth microscope and ZetaPALS potential and particle size analyzer were used to determine and analyze the prepared water samples.The results show that the ASP flooding prepared simulation water contains a large number of fine oil droplets.The average particle size is 1.875 ?m.Its viscosity is 2.862 mPa·s,and the zeta potential is-45.51 mV.In the second part,polyether PPS was synthesized.The effects of reaction time,reaction temperature,molar ratio between reactants,and the amount of reaction solvent on the conversion of reaction were investigated;adsorbent ZIF-8 was synthesized by volatilization at room temperature;PPS@ZIF-8 were synthesized by hydrothermal reaction.BET,SEM,FTIR,XPS,XRD,and TG,etc.were used to characterize and analyze the surface area,pore volume,morphology,structure and group,surface element,crystal structure and thermal stability of PPS,ZIF-8,and PPS@ZIF-8.At the same time,it was proved that PPS was grafted onto ZIF-8,PPS@ZIF-8 is more lipophilic and has good hydrothermal stability.In the third part,the demulsification performance of PPS for produced water from ASP flooding was explored.The effects of demulsifier dosage,demulsification time and demulsification temperature on the demulsification performance of PPS were investigated.The adsorption performance of ZIF-8 on the fine oil droplets in the produced water of ASP flooding was studied,including the effect of adsorbent dosage,adsorption temperature and time on the adsorption effect of ZIF-8.The adsorption model of ZIF-8 was established,and the dynamics and thermodynamic mechanism of ZIF-8 adsorbing fine oil droplets in produced water were analyzed and clarified.In the last part,the demulsification-adsorption performance of PPS@ZIF-8 to the produced water from ASP flooding was explored.The effects of different ratios of PPS and ZIF-8,as well as the dosage,processing time,and temperature were investigated.In addition,the Zeta potential and particle size changes of the fine oil droplets in produced water of ASP flooding after the treatment were further analyzed.This paper consists of 44 figures,5 tables and 95 references.