脈衝袋濾系統之設計參數研究

Abstract

脈衝袋濾系統是各型袋濾器的主流。在設計參數的研究上，需同時考慮濾 布過濾及脈衝洗袋兩方面的問題。本研究以壓力降、過濾效率及脈衝洗袋 效率為重點進行實驗，來探討脈衝袋濾系統之設計參數。由實驗結果顯示 ，在比較高的過濾速度之下，粉塵餅有被壓縮的現象，因此過率速度的設 計不宜太高。預測壓力降的主要參數 K2（比粉塵阻抗係數）的實驗值在 本研究中發現與 Williams et al. 所預測值相近。在過濾效率方面，不 論過濾速度與濾布種類為何，總過濾效率的值發現均幾乎可達100%，且其 中以0.1μｍ粒徑大小的粉塵的穿透率為最高。這是因為在過濾過程中， 剛開始的過濾是由濾布所控制，而在有效過濾期之後則由粉塵餅所控制的 緣故。在洗袋效率方面，本研究發現粉塵附著密度較大者，粉塵較容易被 去除。在相同壓力脈衝之下，尖峰靜壓較大者，洗袋效率較佳。最後，根 據當粉塵所受拉曳力與黏著力的平衡關係，本研究提出一個預測洗袋效率 的方法，結果發現脈衝洗袋的理論值與實驗值頗能吻合。 The pulse jet fabric filtration system is the main stream among various fabric filtration systems. In the design of a pulse jet fabric filtration system, both fabric filtration and pulse jet cleaning must be considered. This study has investigated pressure drop, filtration efficiency, and pulse jet cleaning efficiency of a pulse jet fabric filtration system in the laboratory. According to the experimental results, the dust cake has been found to be compressed substantially when filtration velocity is high. In order to avoid "blinding" of the fabric, the restriction of the filtration velocity below a certain value is important. The K2 (specific dust resistance coefficient) is the main parameter to predict pressure drop. Experimental data of K2 has been found to fit well with the equation by Williams et al. Total filtration efficiency has been found to reach nearly 100% within the first minute of filtration. Particle close to 0.1μｍ have been found to have the highest penetration regardless of the type of fabrics and filtration velocity. This is because that the characteristic of fabric dominates the initial period of filtration, and the dust cake dominates the filtration process afterwards. In the aspect of pulse jet cleaning efficiency, it has been found that dust particles are removed ea er when the dust areal density is greater. At the same pressur impulse, the pulse jet cleaning effienciency has been found to be higher when the peak static pressure is higher. A model has been developed to predict the pulse jet cleaning efficiency by considering the balance between the adhesion force and drag force on particles. The theoretical results of pulse jet cleaning efficiency have been found to fit well with the experimental data.