Classification Characteristics of a Cyclone Type Classifier with Improved Collection Boxes for Separating Particles near the Wall Surface

• Oshitari Teruo

  Department of Chemical Engineering, Hiroshima University Soken Chemical & Engineering Co., Ltd.

• Yamamoto Kazumi

  Soken Chemical & Engineering Co., Ltd.

• Fukui Kunihiro

  Department of Chemical Engineering, Hiroshima University

• Yoshida Hideto

  Department of Chemical Engineering, Hiroshima University

抄録

Cyclone separators are used in many processes to remove powders for collection in a wide range of diameters. When the cyclone separator is used as a classification device that requires high effectiveness, the 50% cut-off size (D_p50) is restricted to less than several microns owing to the strong centrifugal force. We developed a cyclone-type classifier to effectively classify coarse particles collected by the normal cyclone, as discussed in our previous study. The classifier comprises inner and outer collection boxes with a sloping channel region between the upper sections. The sloping channel could derive the additional air, called blow-up flow, from the tangent nozzle established in the outer box. The blow-up flow becomes confluent with the main swirling flow of the cyclone. In the channel, the fine particles affected by the drag of the blow-up flow were collected in the inner box. Additionally, the coarse particles affected by the centrifugal force induced by the swirling flow were collected in the outer box. The previous study, regarding a classifier with a channel length of 6 mm, demonstrated that D_p50 and the effectiveness of the classification κ, which is the ratio of the 25% cut-off size to the 75% cut-off size (D_p25/D_p75), increase linearly with the increase in blow-up flow rate (Δq). In this study, we increased the channel length from 6 to 23 mm. This resulted in the following beneficial characteristics for separating acrylic particles having a size distribution of 15–35 µm. Unlike the previous study, D_p50 depended on the main flow rate at the entrance regardless of Δq since the increase in Δq increases the centrifugal force, which acts simultaneously on the D_p50 particles, and the drag force. Meanwhile, κ increased significantly with the increase in Δq. The classifier classified the particles with high effectiveness (κ ranging from 0.75 to 0.92).

収録刊行物

• JOURNAL OF CHEMICAL ENGINEERING OF JAPAN

  JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 50 (7), 492-500, 2017

  公益社団法人 化学工学会

キーワード

• Gas-Cyclone
• Particle Separation
• Cut-Off Size
• Classification Effectiveness
• Sharpness Index

詳細情報

• CRID: 1390282679544913408
• NII論文ID: 130005815311
• NII書誌ID: AA00709658
• DOI: 10.1252/jcej.16we267
• ISSN: 18811299
• ISSN: 00219592
• NDL書誌ID: 028386784
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I028386784
• Web Site: https://www.jstage.jst.go.jp/article/jcej/50/7/50_16we267/_pdf
• 本文言語コード: en
• データソース種別:
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  • NDL
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