Separation Performance Of Multi-tube Cyclone Separator And Optimization Design Of Guide Vane

Multi-tube cyclone separator is a kind of gas-solid separation device. It is widely used in the process of natural gas purification treatment technology in gas transmission because of its simple structure and high separation efficiency. Particles can be separated in the multi-tube cyclone separator and its key parts are guide vane cyclone tube. Gas-solid mixture are got into cyclone tube along the axial direction, and then its axial movement is turned to tangential movement via guide vanes. Particles can be separated from the mixture by the density difference between gas and solid. At present, the main multi-tube cyclone separators used at gas transmission station are parallel composed by some guide vane cyclone tubes whose cylinder diameter are between 50 and 150 mm. When compared with the tangential inlet structure, this kind of multi-tube cyclone separator possesses advantages of small area, large capacity and so on.At the moment, the separation performance of multi-tube cyclone separator is not very good. On one hand, blockage is formed in the process of pigging because large number of particles accumulates in the separator. On the other hand, high load of filter separator, frequently replacement of filter elements, high operation cost of running are made due to the low separation efficiency. Meanwhile, because of low separation efficiency, the downstream pressure regulating and metering devices could be failed, and the running life of cyclone separator may be shorted. With the improvement requirement of energy-saving emission reduction efforts, not only high separation efficiency but also low pressure drop are required. Therefore, the inner fluid field of multi-tube cyclone separator has been analyzed detailly by using numerical simulation method combined with theoretical analysis method, based on computational fluid dynamics, multiphase flow theory. And the regularities of separation performances under different operating conditions have been studied, too. At the same time, the guide vane structure on single cyclone tube has been also optimized. Theoretical guidances have been provided to site operation of multi-tube cyclone separator by all these studies. Concrete research contents are shown as follows:Firstly, gas fluid field of multi-tube cyclone separator was simulated to analyze its pressure and velocity field, and the flow regularity of them was got, based on navier-stokes and continuity equations by using a turbulence model named RNG k-epsilon and a method called the finite volume. At the same time, it was studied that the influence of different inlet velocities on inlet gas fluctuation of every single cyclone tube. When the gas fluid field became steady, DPM (Discrete Phase Model) need to be added to simulate the separation process of gas and solid phases, after that the grade separation efficiency and pressure drop of multi-tube cyclone separator were revieved. All at once, the changing regularities under different fluid inlet velocity, particle diameter, particle density, operating pressure and particle concentration about separation efficiency and pressure drop of multi-tube cyclone separator were studied to provide a kind of theoretical guidance for the filed operation.Secondly, the regularities of separation efficiency and pressure drop were got about six parameters namely number, thickness, distance between fluid inlet and guide vanes' inlet, outlet angle, arc length and height of guide vanes in cyclone tube, so did their corresponding equations by using the single variable method. Besides, three different structures of guide vanes named wedged, curved and spindle were analyzed to compare their separation efficiency and pressure drop. Through all these studies, a foundation was laied to optimize the single cyclone tube.Thirdly, guide vanes were optimized by RSM method and numerical calculation. An optimization mathematical model need to be established. In tihis model, the maximum separation efficiency and the minimum pressure drop were chosen to be objective function, while guide vanes'number, thickness, arc length and height were chosen to be design variables. The response surface mode of guide vanes must be received and the optimal control parameters must be worked out to get the optimization model of guide vanes, through regression analysis about the quadratic response surface of separation efficiency and pressure drop. Finally, a laboratory experiment need to be done to measure the grade separation efficiency and pressure drop of single tube. What was more, the experimental results must be in a good conformity degree with the simulation results.In this paper, the separation performance of multi-tube cyclone separator used in gas station has been researched based on the fluent software, which provided a guiding significane for site operation. In addition, guide vanes have been optimized combining with the RSM method, which provided a reference sense to improve the separation performance of cyclone tube.