Research On Application Of Vibrated Fluidization Technology In Lignite Drying

There is a large reserve of lignite in china, but its moisture content is high, so it needs to be dried before used. Comprehensively compare with other lignite drying technology at home and abroad, the VFB drying technology is most suitable for industry because it is not only suitable for mass production but also of a better drying effect. As a result,VFB drying technology is of a great promotional value. This paper conducts research on the vibrated fluidization technology which is used in lignite drying, and Summarize the working mechanism and the internal regularity of this technology to apply to guide and assist the actual design.The computer numerical simulation method is used to research vibration fluidized technology in this paper. Firstly, we choose the two-fluid model is chose as CFD model. Secondly, the most popular CFD software Fluent is used to simulate fluidized bed, then the simulate critical fluidization velocity is compared with the actual one to get a group of simulate models for fluidized bed which have the smaller error in the two value. Thirdly, the dynamic meshing model is combined with the fluidized bed model to simulate VFB. Lastly, this VFB simulation model is used to research how vibration affect on fluidization with different boundary condition and initial parameters. According to simulate results:Firstly, the introduction of vibration can reduce critical fluidization velocity; Secondly, the introduction of vibration can promote fluidization of the low layer material in VFB and expansion of the bed; Thirdly, the introduction of vibration can promote the fluidized uniformity of materials; Fourthly, the introduction of vibration can make materials which are mixed by particles with different diameter in VFB appear segregation phenomenon that the bigger diameter particles are the lower position it distribute. The research conclusion above can provide a important guidance for systematic process, structure of VFB and parameters in Lignite drying, and explain the advantages of vibrated fluidization technology in lignite drying. Firstly, it needs a lower operating gas-velocity which can achieve the needed fluidization state; Secondly,it obviously promotes the drying uniformity of lignite; Lastly, it promotes the stability and security of system. In last chapter the50t/h lignite vibrated fluidization drying system is designed base on the advantages above. First, we design the system scheme, and guarantee its feasibility. Then, we calculate systematic process parameters, it contains the sizes of fluidized-bed’s structure and the operation parameters of system; At last, we check parameters to confirm if they are reasonable and calculate the fluidized height of materials by using Fluent software.