Research On The Dielectric Properties Of W/O Emulsion In Alternating Electric Field

In order to enhance the oil recovery ratio, people have used a lot of oil production methods,thus the water content of crude oil increased. The water in crude oil is harmful. In order tonormal the production, we must dehydrate the crude oil. There are a lot of methods todehydrate crude oil, and the electric demulsification method is widely used because of itsclear advantages. Though there are a lot of research results of electric demulsification and itstechnology, the theoretical system has not yet formed. Also, the micro process ofdemulsification under the electric field was still not clear enough. In order to observe theproperties of the emulsion in the external electric field clearly, we must prepare the stableemulsion firstly.By a large number of trials, we got the suitable conditions for preparing the emulsion, suchas mixing intensity, mixing time and temperature. So in order to observe the mechanism ofdemulsification under an external alternating electric field from a micro perspective, we gotsome valuable information pictures about the movement of the droplets by the opticalmicroscope with CCD. We find that the droplets deformed in alternating electric field. If theelectric field strength was higher than the critical electric field strength, the droplets ruptured.The changes of frequency didn’t affect the deformation of droplets in the measurement range,but it made the droplets coalescence.In order to study the dielectric properties of emulsion, this paper measured the dielectricspectrum of emulsion under alternating electric field and analyzed the rule of curve. It provedthat the relative dielectric constant of emulsion decreased with the increase of frequency. Andit was affected by water content. The dielectric constant decreased as the content of waterreduced. At the same time, the dielectric constant of emulsion increased as the externalelectric field increased. The change of emulsion dielectric loss was different in high frequency and low frequency area. In the low frequency areas, the loss reduced with the increase offrequency. And it was just the reverse in the high frequency area. The influence of watercontent on the dielectric loss was also different in high frequency and low frequency areas.At last, the paper studied the Cole-Cole figure of the emulsion, and concluded that therewere two types of polarization of the emulsion under alternating electric field. Then itconfirmed this conclusion through the analysis of the equivalent circuit of emulsion.