Numerical Simulation Of Flow Field Distribution In A Multi-unit Process Coupled Cyclone Reactor

With the increasingly stringent requirements for environmental protection and energy conservation,alkylated oil has become an ideal blending component of gasoline due to its high octane number and low sulfur content.In the alkylation reaction equipment,the cyclone reactor can realize the full mixing of the catalyst and the hydrocarbon material through the special structural characteristics,and can complete the timely separation of the target product and the catalyst at the same time,which improves the quality and yield of the target product.In this thesis,based on the Fluent software platform,through a combination of theoretical analysis and numerical simulation,the flow field distribution characteristics in the cyclone reactor are studied and analyzed.The research on this topic provides a theoretical basis for the structural optimization of the cyclone reactor.First,the development status of the alkylation reaction device is introduced,and the research progress of the cyclone reactor as a new type of alkylation reaction device is introduced.At the same time,the turbulent mixing mechanism and the droplet breaking mechanism are introduced to provide theoretical guidance for the flow field mixing process.Because the cyclone reactor studied in this thesis is in the early stage of research,the cold model research method is adopted,kerosene is selected as the dispersed phase fluid,74% glycerin aqueous solution is selected as the continuous phase fluid,and the Reynolds stress turbulence model and the European Draw a two-fluid model to conduct a numerical simulation study on the flow field of the cyclone reactor.Secondly,the velocity field distribution of the dispersed phase,the concentration field distribution of the dispersed phase,and the double "M" distribution of the tangential velocity of the dispersed phase in the cyclone reactor are studied,and the mixing performance of the two-phase fluid is quantified by the dispersion uniformity deviation.The research results show that the tangential velocity is converse to the flow field.The distribution has the greatest influence and can directly affect the mixing and separation process of the two-phase fluid.The axial velocity affects the contact time of the two-phase fluid,thereby affecting the mixing and separation effect of the two-phase fluid.The radial velocity has the smallest value,but it can directly affect the dispersion of the dispersed phase.Radial movement position;the concentration of the dispersed phase is the highest in the axis area,and the closer to the underflow port along the axial direction,the lower the concentration;in the mixing chamber,the closer to the overflow port,the more obvious the double "M" distribution,and at the same time,the dispersion is even The greater the deviation,the double "M" distribution is not conducive to the mixing process of the two-phase fluid.Finally,the effects of different structural parameters on the flow field distribution and the mixing performance of two-phase fluids are studied.The results show that as the number of tangential slit entrances increases,the tangential velocity gradually decreases,and the axial velocity is numerically valued at n=2 The largest,the tangential slit entrance angle has the least influence on the tangential speed and axial speed.When the tangential slit entrance height is 65 mm,the tangential speed and axial speed are the largest.In addition,as the entrance height of the tangential slit increases,The tangential and axial speeds gradually decrease;under different structural parameters,the double "M" distribution phenomenon is gradually strengthened as the cross-section position in the mixing cavity is close to the overflow port,and the double "M" distribution area is concentrated in the cross section z=50mm to z =70mm.At the same time,under different structural parameters,the dispersion uniformity deviation gradually increases with the position of the cross section in the mixing chamber close to the overflow port,indicating that under different structural parameters,the double "M" distribution is not conducive to the mixing process of the two-phase fluid in the mixing chamber.Close to the two-phase fluid inlet position,the more violent the flow,the flow disturbance will produce swirling flow,resulting in unstable flow field and poor dispersion;when the inlet structure parameters are n=2,a=13°,and l=65mm,the dispersion uniformity deviation is The average growth rate is slow and the value is the smallest.At this time,the flow field distribution brought by the structural parameters is the most stable and the mixing effect is the best,which is beneficial to the full mixing of the two-phase fluid in the cyclone reactor.