The Effect Of Microwave Irradiation On The Properties Of High Pour Point Oil

With the large consumption and continuous exploitation of oil,light oil resources are becoming less and less.It is increasingly urgent to develop and utilize unconventional oil resources such as the oil with high pour point or high viscosity.Therefore,it is of great significance to study the viscosity reduction technology of heavy oil.Microwave technology has the potential for viscosity reduction,however,it was found that the reduction efficiency is not stable.Microwave electromagnetic fields can irreversibly reduce viscosity for some crude oils,but may increase viscosity for others.This problem has not been solved fundamentally because there is still a lack of systematic and profound understanding of the direction of microwave action and the maximization of its effect.The theoretical principle of microwave viscosity reduction technology is critical to its practical application.In this paper,the simulated oil samples with high pour point were selected.The molecular dynamics simulation method and experimental method were combined to analyze the intrinsic relationship between the properties of high pour point oil and its component molecules,as well as the effect of microwave electromagnetic field on the properties of high pour point oil.Firstly,the effects of applied electric field on the viscosity,dipole moment,radial distribution function between molecules,the mean square displacement and diffusion coefficient of paraffin molecules in the simulation system were investigated by using molecular dynamics simulation software.Then,the effects of microwave power and the alternative application of microwave electronic and magnetic field on viscosity and dielectric properties were investigated experimentally.Results show that:(1)According to the calculation of molecular dynamics,the viscosity of the model system is first decreased and then increased with the increase of the applied electric field intensity at the same electric field frequency.The greater the polarity of paraffin molecules,the greater the influence of electric field.The mean square displacement and diffusion coefficient of paraffin molecules decrease under appropriate electric field intensity.The viscosity of the system is decreased because the motion of the molecules is blocked and the aggregation of the paraffin molecules is inhibited by the electric field at this time.When the appropriate electric field intensity is selected,the aggregation of paraffin molecules in the system can be inhibited effectively.(2)The viscosity of the model system is first decreased and then increased with the increase of the applied electric field frequency at the same electric field intensity.Each substance responds to microwaves at a different frequency.The closer the frequency of the applied electric field is to the response frequency of the paraffin molecules,the stronger the interaction between the molecules and the electric field is.The viscosity is decreased because the diffusion of the molecules is reduced.When the electric field frequency is too high,the electric field can accelerate the movement of paraffin molecules and promote the aggregation of paraffin molecules.At this time,in addition to the aggregation of paraffin molecules,there is also a slight aggregation between the longer chain paraffin molecules and the shorter chain alkanes and aromatic hydrocarbon molecules in the model system.(3)The length of waveguide has a great influence on the electromagnetic field distribution in single mode cavity microwave device.With the same microwave power value,the electromagnetic field distribution,port reflection coefficient and power loss density of the oil sample change with the waveguide length.(4)Microwave can significantly change the viscosity of the simulated oil sample.The influence varies with different microwave power levels and distribution of the electromagnetic field.