Study On The Enhanced Demulsification And Dehydration Characteristics Of High-Pressure Pulse-Swirl Coupling Device

In the process of obtaining oil products in metallurgical chemistry,lube oil purification,oil extraction,waste oil recovery and other related fields,it is easy to form water-in-oil（W/O）emulsions that are stable and difficult to separate,and the demulsification and dehydration treatment is one of the most important aspects of making full use of petroleum resources,increasing the output and quality of oil products,saving energy and reducing emissions,and protecting the environment.In order to save resources and improve the treatment process of oil-water emulsions,combining the advantages of low energy consumption of pulse electric field demulsification and high efficiency of centrifugal separation,and resulting in enhanced demulsification and dehydration efficiency.A fan electrode device was designed to study the collision,rupture,agglomeration,chain formation,and other behaviors of droplets in a high-pressure pulse electrostatic field.The results showed that:i)The chain formation speed（V）of droplets increased with the voltage（U）amplitude,but U that is too large can promote the agglomeration of droplets on the chain,affecting the droplet arrangement and changing the shape of the chain.As the frequency（?）increased,V first increased and then decreased,with a maximum value of 0.2515μm·s^-1at 300Hz.ii)Compared to the volume difference and U,?had a greater effect on the plastic collision velocity（V₁,V₂）.The addition of anhydrous ethanol,a non-electrolyte that hinders charge migration,and Na Cl,an electrolyte that promotes charge migration,to the emulsion showed that the non-electrolyte intensifies the dipole motion of droplets and increases the collision velocity(V₂ maximums of 9.451μm·s^-1and 8.577μm·s^-1,respectively).The electrolyte enhances the conductivity of the emulsion,promotes charge migration and neutralization,and reduces the collision velocity by hindering the polarization motion of droplets(V₂ maximums of 3.082μm·s^-1and 4.246μm·s^-1,respectively).When adding non-electrolytes,the influence of electrical parameters on V₂ is greater than that of the diameter ratio（Ψ）and volume,while adding electrolytes,Ψhas the greatest influence on V₂,followed by volume and electrical parameters.The electric-swirl coupling procedure is designed through a user-defined scalar function,and the dual-field coupling numerical calculation method is optimized.The four structural parameters that have the most significant impact on the dehydration performance of the diversion coupled cyclone were selected using the steepest climb design:axial length of the spiral flow channel,diameter of the overflow pipe,angle of the underflow inverted cone,and length of the separation section.Single-factor tests were conducted to obtain the optimal solutions of 16mm,11mm,20°,and 140mm in turn.The operating parameters of the coupled cyclone,including voltage,inlet flow rate,and splitting ratio,were optimized using the central composite design,and the optimal solutions of 466.43V,1.32m³·h^-1,and 0.86 were obtained,respectively.Using the DPM model to study the motion behavior of droplets in the coupled cyclone,two droplet particles were symmetrically injected at the axial inlet.The following findings were observed:i)When the voltage ranged from 0 to 6000V,one particle escaped from the overflow port and the other particle was captured by the underflow port.As the voltage increased,the escaped particle moved closer to the bottom of the inverted cone,while the captured particle moved closer to the lower surface of the underflow tube.When the voltage was between9000V and 12000V,both particles were captured by the underflow port.As the voltage increased,the droplet motion became more unstable and the motion time near the inverted cone became longer,making it easier for the particles to be discharged from the underflow port.ii)When the frequency was increased from 0.1Hz to 1000Hz,there was no significant difference observed in the trajectories and velocities of both particles.iii)When the flow rate was between 0.6m³·h^-1and 1.2m³·h^-1,one particle escaped from the overflow and one particle was captured by the underflow.However,when the flow rate was 1.4m³·h^-1,both particles were captured by the underflow port.As the flow rate increased,the particles gradually moved toward the underflow pipe and were eventually discharged from the underflow port.