Research On The Effect Of Polar Subtances On Wax Characteristics Of Model Waxy Oils

Most of the crude oil produced in China is waxy crude oil.Because it contains a large amount of wax,the crude oil has poor flowability below the wax appearance point,which brings many potential hazards to the production work.When the oil temperature drops below the gelation temperature,the crude oil will gel.The fundamental reason is that the crystallization of wax forms a network structure with high strength,resulting in the loss of flowability of the crude oil.Resins are generally the most abundant polar component in crude oil system.Although wax plays a key role in the gelling behavior of waxy oil,as a molecule with polar groups and non-polar ends,resins can affect the crystallization process of wax molecules and change the properties,morphology,structure and other characteristics of wax crystals,thus affecting the gelling.In this thesis,the mixed resins are divided into three resin sub components to prepare wax containing model oil with different polar resin sub components.It is found that:(1)With the increase of the content of resin sub components,the wax appearance point,cumulative wax precipitation,gelation temperature and yield stress of waxy model oil show a monotonous decreasing trend,indicating that resin sub components can inhibit the crystallization and precipitation of wax,delay the gelling behavior and weaken the strength of gelling structure.With the increase of the polarity of resin sub components,the above four variables show an upward trend,indicating that the weaker the polarity of resin sub components,the stronger the inhibition of wax crystal precipitation and the more obvious the weakening of the strength of gelling structure.(2)In the aspect of microstructure,with the increase of the content of resin sub components,the wax crystal particles gradually become smaller,and the morphology of wax crystal gradually changes from needle shape to ellipse shape,and finally almost close to point shape;With the increase of the polarity of resin sub components,the size of wax crystal particles increases,indicating that the stronger the polarity of resin,the more conducive it is for wax crystals to aggregate into larger particles.(3)In terms of the microstructure of wax crystals,the average grain size of wax crystals decreases monotonically with the increase of the content of resin sub components.Similarly,with the increase of the polarity of resin sub components,the average grain size of wax crystals increases monotonously,which is the same as the change law of the average grain size of wax crystals under the microscope,indicating that the change of microstructure has an impact on the morphology of wax crystals.(4)The lattice parameter c showed a monotonous increasing trend with the increase of the content of resin sub components,indicating that the structure of the smallest unit cell of wax crystal changed due to the addition of resin sub components and the increase of content;With the increase of the polarity of resin sub components,the lattice parameter c shows a decreasing trend,indicating that the increase of the polarity of resin sub components leads to the decrease of the variation range of lattice parameter c,indicating that the stronger the polarity of resin sub components,the smaller the influence on the cell structure of wax crystals.