| Plate column is widely used in oil refining,petrochemical,fine chemical,food,medicine and environmental protection industries.The phenomenon of gas-liquid entrainment in plate column will seriously reduce the efficiency of the plate column.Further,high-throughput and even ultra-high-flux transformation in the plate column would lead to more serious gas-liquid entrainment.However,the problem of gas-liquid entrainment in plate column has not been well solved.In other words,gas-liquid entrainment at some point restricts the development of high-throughput plate column.Therefore,it is of high engineering application value and social significance to develop a high-efficient and compact gas removing liquid entrainment device.Several efficient and compact cyclone separator schemes for the entrainment of degassed liquid in a tray column were proposed.Numerical methods were used to study the separation performance of the separators and the influence of the structural parameters on the separation efficiency.The structure of the device was optimized.Moreover,the pressure drop calculation of the separator was studied.The main research contents and conclusions are as follows:(1)Based on the idea of cyclone separation,three new types of gas-liquid cyclone separators were proposed and studied numerically.The simulation results show that the separators proposed are highly efficient and compact,which can be used to solve the entrainment of gas-liquid in the plate tower.After a comprehensive comparison and analysis,a GLCC-type cyclone separator with multiple symmetrical tangential inlets and mix tube segment combinations was determined as the best solution.(2)A new unsteady simulation method of multiphase flow is developed,in which the steady state simulation is used before the non-steady state simulation.Specifically,unsteady state simulation is not replaced to complete the simulation until the residual is lower than a certain level.Compared with the test data in the verification case,it is found that the new simulation method can shorten the 2/3 time of numerical calculation,and the precision of the new method is about the same as that for the direct unsteady simulation method.(3)The influence of the structure parameters of the separator on the separation efficiency of the cyclone separator is studied with the FLUENT software.Also,the concrete structure of the separator is optimized.The research process includes: the influence of the number of inlets on the deviation of the cyclone center from the geometric center of the separator(eccentric phenomenon),the determination of the “best” aspect ratio(the ratio of length to diameter)of the separator,the determination of the optimal number of inlets,the optimization of the liquid outlet structure,and separator pressure drop estimation etc.The results of the study show that a plurality of symmetrical tangential inlets can greatly improve the eccentricity in the cyclone separator;the optimum number of inlets for the cyclone separator is 4 and the “best” aspect ratio is 3.5.The optimized liquid outlet structure is a vertical outlet with an annular sump.The objective of this paper is to develop a cyclone separator which is used in the tray column to remove the gas-liquid entrainment.Further,the optimized cyclone separator scheme can fundamentally solve the gas-liquid entrainment problem in the plate column,which provides a simple and efficient solution for the plate column to the ultra-high Throughput transformation. |
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