Study On Coordinated Regulation Of EVA Crude Pour Point Depressant Performance By Modified Nano-SiO₂/MMT

Most of the crude oils have high wax content,pour point and viscosity in the world today.The low temperature fluidity is very poor,which has caused great troubles for oil storage and transportation.Therefore,reduce the pour point and viscosity of the crude oil at low temperature is the best method to solve this difficulty.Adding chemical pour point depressant is the most convenient and economical method.Developing the new nano-composite pour point depressant can achieve better results.This study used EVA crude oil pour point depressant as the basic pour point depressant,and selected three kinds of EVA drop into daqing crude oil with different VA content,and determine the pour point of crude oil,analyzed EVA28 has the best effect of daqing crude oil.We used nano-SiO₂ and montmorillonite（MMT）and organicallymodify them,and then analyzed the structure before and after modification by infrared spectroscopy and water contact angle.The modified nano-SiO₂ and MMT were made into different ratios nano-composite pour point depressants with EVA.They were applied to Daqing crude oil,and measured pour point and viscosity-temperature,and observed their wax crystal structure.Analyzing the mechanism and causes by the changes of the pour point,viscosity-temperature curve and wax rycstal structure.It can analyzed that the nano-composite pour point depressant combines with the wax crystal through heterogeneous nucleation by the changes of the pour point,viscosity-temperature curve and wax rycstal structure,which has different mechanism of action with the traditional pour point depressant.Thus has better synergy with EVA and has a better effect on Daqing crude oil.Through the structural analysis of the wax crystal polarized microscope,it is known that the different wax crystal structure will affect the effect of the nano-composite pour point depressant on Daqing crude oil.The main reason for the difference in the shape and structure of the wax crystal is due to the different structure of the nano-SiO₂ and MMT.We combined modified nano-SiO₂ and MMT to make nano-composite pour point depressants with different ratios,which were used to analyze the effects of different wax crystal structures on the low temperature rheology of Daqing crude oil.Through experimental analysis,it can be seen that the modified SiO₂ and MMT work together with EVA to have a better effect on Daqing crude oil,which changes the shape of paraffin crystals and the structural strength of wax crystals.Nano-composite pour point depressant can effectively reduce the dosage of traditional pour point depressants and has better pour point depressing and viscosity reducing effects,which brings better economic benefits.