Heavy Oil Blending And Homogenization Flow Field Simulation And Improvement Of Mixing Elements

Dilution technology is one of the common ways of heavy oil transportation.However,it is difficult to achieve light oil's dispersion and dissolution that only relying on the flow disturbance effect,so that it is hard to comply the uniformity of heavy oil and light oil,light oil is wasted greatly.At present,many scholars have studied the uniformity of heavy oil and light oil in wellbore and large tank,while the mixed state of heavy oil mixed with light oil in pipeline is rarely reported.Therefore,the uniformity of heavy oil diluted with light oil in pipeline is studied in this paper through analyzing the distribution of flow field and flow characteristics before and after installing static mixer,and seeking the ways of improving uniformity,which is important to enhance the mixing efficiency and save the light oil resources.This paper analyzes rheological behaviors and viscosity-temperature characteristics of heavy oil named PC,evaluates the viscosity reduction effect of the light oils named XI and X2,the spontaneous diffusion process of simulated oil PCm and X1m of heavy oil PC and light oil X1 was observed.A mixed model of heavy oil and light oil transportation is established,based on the computational fluid dynamics theory.ICEM is used for meshing,the Mixture multiphase flow model is selected.The process of transient change of mixture oil flow field in the natural flow state(the static mixing element is not installed in the pipe)is simulated,the influence of the dilute ratio,oil inlet speed,heavy oil viscosity and diameter of dilution pipeline to the mixing effect of heavy oil and light oil are analyzed.At the same time,the effect of SK and SX mixed elements on the transient changes of the flow field of mixture oil are simulated and the influence of the mixed elements of SK and SX was evaluated,the main influencing factors of the mixing effect is studied.The mixed experimental system of heavy oil mixed with light oil is set up to simulate the mixed state of light oil and heavy oil before and after the installation of SK static element,the comparison between the numerical simulation and the experimental observation results is carried out,wavy mixed components is proposed to improve SK element,flow state in wavy mixed components is simulated and analysed,the rotation angle of wavy mixed component is adjusted to enhance the mixing effect.The results show that the viscosity reduction effect of the light oil X1 is better than that of the light oil X2.When the mixture oil flows naturally,the mixed oil in the pipeline exhibits"light oil-mixed oil-heavy oil" stratified flow phenomenon,because the density of the light oil X2 is smaller,the layered shape is not in center.With the increase of doping ratio,the time which the fluid reaches the steady flow state is shorter,the light oil volume of the pipeline occupied becomes bigger,and the fluid stratification is still obvious.Changing the oil import speed and the size of the dilute pipeline can not effectively improve the mixing effect in the pipeline.The smaller the viscosity difference of this two kinds of oils is,the better the mixed state of the light oil is,but it still can not completely improve the light oil stratification phenomenon.The addition of SK static mixer can significantly improve the stratification of mixed oil,if's mixing effect is better than SX static mixer.With the increase of the number of SK components,the heavy oil and light oil uniformity is higher,but it makes the energy consumption increase,in this paper,the three groups of SK elements are the best.The larger the aspect ratio of the SK element is,the stronger the turbulence fluctuation is.The better the uniformity of the heavy oil and the light oil is,the energy loss is greater.The optimal aspect ratio is 1:1.25 in this model.The wave-shaped mixing element is formed by adjusting SK element,it can make the greater disturbance for fluid,and promote the fluid mixing efficiency.Changing the rotation angle from 180°to 270° can enhance the turbulent kinetic energy of the fluid,so that the distribution of heavy oil volume in pipeline export is more uniform.