Principle And Application Of Aerosol Particles Separation By Reverse Rotation Cyclone

Aerosol particles are the major medium that pollutes the atmosphere and endangers human health. They are produced in industrial processes and industrial exhaust emissions. Therefore, the emissions reduction of aerosol particles during industrial processes and the capture and separation of them in industrial waste are crucial. The separation technology of aerosol particles is widely used and the separation effects directly affect environmental indicators, air quality, and economic benefits. Cyclonic separation technology which is inexpensive, efficient, and easy to operate and maintain has broad application prospects in the capture, recycling, and utilization of aerosol particles, and is a research hotspot in the fields of separation and purification.In this study, the aerosol particle sorting method and the enhancement method for the cyclonic separation of aerosol particles with reverse inlet sorting were proposed. The experimental device for the sorting of aerosol particles and the equipment for cyclone separation and fluid-flow measurement with particle sorting were invented. The particle image velocimetry method, computational fluid dynamics, and the separation experiment were used to study the mechanism on which reverse rotation enhances cyclone separation’s removal of aerosol. A short-process recycle hydrogen desulfurization process was successfully developed and applied. The following research results were obtained:(1) Through combination of theoretical analysis, experimental testing, and optical measurement, the rotating centrifugal flow field was innovatively proposed to realize the sorting of aerosol particles. Experimental measurement and computational fluid simulation were employed to validate the correctness of this method. The common, positive rotation, and reverse rotation regulator were designed, and the corresponding experimental testing system, computational fluid dynamics simulation system, and the image measurement system were established.(2) The experimental test was performed to study the flow rate-pressure drop relationship, the flow rate-efficiency relationship, the Reynolds number-Euler number relationship, the stage efficiency curve, and the fish-hook effect of the three separators. The Reynolds stress model (RSM) was used for the continuous phase and the discrete phase model (DPM) was used for the disperse phase to study the axial velocity, radial velocity, tangential velocity, pressure distribution, and the trajectory, concentration distribution, and separation efficiency of particles in the flow fields within the three separators. The particle image velocimetry (PIV) was used to study the motion and velocity distribution of the flow fields within the three separators, which were compared with the simulation results.(3) Cyclonic separation with reverse-rotating particle sorting caused fine particles to get closer to the wall at the entrance of the separator, and could effectively keep off the short-circuit flow. The highest separation efficiency of reverse rotation cyclone was higher than normal cyclone and positive rotation cyclone both in numerical simulation and experimental research. The residual aerosol concentration in outlet for normal cyclone, positive rotation cyclone, reverse rotation cyclone were0.064mg/L,0.068mg/L,0.010mg/L, when the inlet aerosol concentration was2mg/L. That is to say, the residual aerosol concentration of reverse rotation cyclone is only15.6%of normal cyclone. And the efficient separation scope of the reverse rotation separator was far bigger than that of the other two separators. In the numerical simulation and the optical measurement, cyclonic separation with positive-rotating particle sorting displayed more stable and symmetrical flow field distribution and velocity distribution than the other two separators. The results of the numerical simulation and the optical measurement were highly consistent for cyclonic separation with reverse-rotating particle sorting.(4) Through combination of simulation studies, experimental research, and industrial application experience, the cyclonic separation technology of arranged industrial aerosol particles was successfully developed and applied to the petrochemical hydrogenation unit. When the temperature was50℃, the pressure was13.5MPa, and the sulfur-containing recycle hydrogen was the medium, the average separation efficiency of the separators for droplets of C5+hydrocarbon was85.6%, the purity (mole ratio) of recycle hydrogen increased by2.3%on average, and the molecular weight of gas decreased by0.83on average. The separator was installed at the top inside the desulfurizer, and almost could completely separate the droplets of amine liquid carried by recycle hydrogen. The separator could effectively remove the droplets of hydrocarbon and amine liquid carried by the recycle hydrogen. Various operating indicators satisfied the design requirements, solving the technical difficulties that affect the long cycles of operation of hydrogenation units and recycle hydrogen units and producing significant economic and social benefits.