Study On Flow Field And Performance Of Horizontal Wheel Classifier

As one of the most important equipment in the powder production system,the classifier has a key role in improving the quality of the powder products.The development of the classifier has gone through three stages,namely,centrifugal classifier,cyclone classifier and vortex classifier,at present,the commonly used is vertical wheel classifier.Since the spindle of the vertical wheel classifier is usually used cantilever settings,this kind of setting often produces a series of mechanical problems,such as difficult to ensure dynamic balance,intense vibration,poor sealing and so on.Some scholars proposed horizontal wheel classifier as the fourth generation of high efficiency classifier,can maintain the original high level of classification performance and overcome the structural shortcomings of the vertical wheel classifier,so that the overall structure of the equipment is more reasonable and the operation is more stable.In this paper,a series of studies were carried out on the development of horizontal wheel catalyst classifier in accordance with the requirements of FCC catalyst classification in SINOPEC.The main work and contents are as follows:Firstly,according to the existing structure of jet vortex classifier,a set of basic model is designed,and the performance test and flow field simulation are carried out.Through the experiment,it is found that the coarse particles loss and fine particles entrainment is serious,and the classification performance is unsatisfactory,which is needed to further improve.Through numerical simulation,it is found that the exhaust pipe of the eccentric setting will cause the classification chamber flow asymmetry,thus weakening the classification force field;the flow field of the lower part of the chamber is in disorder,and exists a dead zone of classification;there is a local vortex near the exhaust pipe,which will aggravate particle mixing and increase energy consumption.Secondly,the effects of several parameters on the flow field and performance are investigated.The results show that the distribution of the flow field is more uniform when the main air inlet angle is 45 °.The distribution of the flow block can make the particles more fully dispersed.Concentric set of exhaust pipe and installation of the baffle are conducive to strengthening the classification force field.The set of secondary air is conducive to reducing the loss of coarse particles.According to the above rules,the basic model is improved,and a more reasonable structure model is obtained.Then,a classification wheel is installed in the improved structure and designed into a horizontal wheel classifier.The influence of operating parameters on the classification performance is investigated by experiment.The results show that the classification performance of the horizontal wheel classifier is higher than that of the static classifier.In addition,the formula of particle cut size is deduced by theoretical analysis.Finally,for the dynamic balance of the classifier rotor,the critical speed of the rotor of the horizontal wheel classifier is calculated more accurately.