| The demister is used as to remove the droplets in the flue gas.Therefore,it is one of very important devises in gas purification processes,especially in wet desulfurization system.In order to further increase the separation efficiency of gas liquid,a new type of demister,which is named as free rotary thread demister,is discussed.Here,the separation mechanisms and demisting performances of the free rotary thread demister are investigated.The main contents as follow:(1)The separation mechanisms of a single free rotary thread are analyzed based on the theory of fiber filter.A numerical integration algorithm for the multiple free rotary threads of the inertial impaction efficiencies is proposed based on the separation mechanism of single free rotary thread.The centrifugal separation efficiency of the free rotary thread demister is established by the limit trajectory method.Therefore,the overall mist separation efficiency of the multiple free rotary threads and double-layers free rotary thread can be developed theoretically by the separation efficiency of the single thread.From the quantity analysis,it is found that the main separation mechanisms of free rotary thread demister are the inertial impaction and centrifugal separation.(2)It is necessary to conduct experimental study on separation efficiency and pressure loss experiment of the free rotary thread demister in order to prove the separation performance of free rotary thread demister.For horizontal single-layer free rotary thread demister,the experimental results show that the demisting efficiency increases exponentially with the number of the rotary threads.When the rotary speed is less than 900 rpm,the demisting efficiency is approximately linear with the rotary speed.When the rotary speed exceeds 900 rpm,the growth rate of the demisting efficiency is obviously slowed down.The pressure loss of the rotary thread is linear with the increase of the number of the rotary thread.However,the pressure loss will be increasing remarkably with rotary speed.The results show that the relation between the pressure loss and the rotary speed follow the power function.Taking both the high efficiency and the low resistance into account,it is more reasonable to increase the number of the rotary thread rather than to increase the rotary speed.(3)In order to improve the separation efficiency and satisfy the industrial application requirement of the free rotary thread demister,a vertical double-layer free rotary thread demister is proposed based on the horizontal free rotary thread demister.In this experiment,the rotary fabric thread diameter is 3 mm,the number of the rotary thread per layer is 200.When the rotary speed exceeds 500 rpm,the water spray medium diameter is 20.07?m and the velocity is 5m/s,the demisting efficiency is greater than 98%.(4)According to the comparative study on theoretical and experimental classification efficiency of free rotary thread demister,it presents a good agreement between the experimental and theoretical classification efficiency at the different of the droplet diameter,the rotary speed,and the layers of the free rotary thread.When the number of rotary threads per layer is 200 and the rotary speed is 500 rpm in the vertical double-layer free rotary thread demister,the values of the theoretical and the experimental classification efficiency are almost same.This is indicated that the separation theory of the free rotary thread demister established is quite reasonable. |
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