单列滤筒脉冲清灰过程粉尘分布与喷吹控制研究

Study on dust distribution characteristics and dust-cleaning optimization during the pulse cleaning process for the uniseriate filter cartridges

  • 摘要: 滤筒除尘技术应用广泛,其清灰效果直接影响除尘效率。为了解决滤筒表面清灰不均等问题,以单滤筒除尘器脉冲喷吹清灰过程为研究对象,将实验研究与数值模拟方法相结合,分析脉冲喷吹清灰过程的气流分布特征并优化了流场,实验与模拟研究结果一致性较好,2者均发现安装散流器有利于提高滤筒上部区域的清灰效率,安装散流器后,底部测点的峰值和谷值压力绝对值较安装前分别减小了约20%与27%,减缓了高速气流对滤筒底部的冲击,有利于保护滤筒。基于所得散流器的优化结果,构建了由5个滤筒构成的单列滤筒的三维物理模型,将CFD-DPM方法、多孔介质模型和脉冲喷吹作用相结合,开展了单列滤筒脉冲喷吹清灰过程及喷吹模式的研究,可视化分析了滤筒除尘器脉冲喷吹过程中粉尘从滤筒侧壁剥离、在滤筒周围扩散到沉积的全过程;再次吸附现象明显,基于自主开发的后处理程序,定量分析了不同滤筒再次吸附的强弱。同时,为了优化喷吹控制,比较了同时喷吹、顺序喷吹和跳序喷吹3种不同脉冲喷吹模式对再次吸附与PM2.5分布的影响规律,发现处于中间位置的滤筒C表面的细微颗粒PM2.5的清灰效果均相对较差;跳序喷吹可有效抑制剥落粉尘的再次吸附,整体清灰效果优于同时喷吹和顺序喷吹;获得了跳序喷吹的优化控制方案,提高了滤筒除尘器的清灰效率。为提高细微粉尘的清灰效率提供了指导,对改善滤筒除尘器脉冲喷吹控制具有重要的实际意义。

     

    Abstract: Dust removal technology of filter cartridges is widely used, and the cleaning effect directly affects the dust removal efficiency. In order to solve the problem of uneven dust cleaning effect on the surface of the filter cartridge, the dust cleaning process of the pulse injection for a filter cartridge was selected as the research object, and the experimental research with the numerical simulation method was adopted, the air flow distribution characteristics of the pulse for the cleaning process were analyzed and the flow field was optimized. The experimental and simulation results were in good agreement. Both found that the installation of a diffuser was conducive to improve the dust cleaning efficiency in the upper area of the filter cartridge. After installing the diffuser, the absolute values of the peak and the valley pressure at the bottom point decreases by about 20% and 27% respectively when compared to the condition before the optimization, it can retard the impacting from the jet stream on the bottom area of the filter cartridge, which was conducive to protect the filter cartridge. Based on the optimization results of the diffuser obtained, a three-dimensional physical model of a uniseriate filter cartridges of five ones was constructed. Combining the CFD-DPM method, the porous medium model and the pulse injection effect, the pulse cleaning process was investigated, as well as the mode of the injection control. The entire process from dust diffusion to its deposition around the filter cartridge was visually investigated. The re-adsorption phenomenon is obvious. Based on the self-developed post-processing programs, the strength of the re-adsorption phenomenon for different filter cartridges was quantitatively analyzed. Meanwhile, in order to optimize the injection control, the influence of three different modes on the pulse injection was considered on the influence of the re-adsorption phenomenon and PM2.5 distribution during cleaning process. It was found that the cleaning effects of fine particles of PM2.5 on the surface of Cartridge C in the middle position were relatively poor. The skip injection can effectively suppress the re-adsorption phenomenon of dust, and the cleaning effect of the whole filter cartridges is better than those of the simultaneous and sequential injections. An optimized control scheme for the skip sequence injection was obtained, which improved the dust removal efficiency of the filter cartridge for the dust collector. It provides guidances for improving the cleaning efficiency of fine dust and has important practical significance to improve the pulse injection control of the filter cartridge for the dust collectors.

     

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