Attrition of High Bulk Density Granules by Blow-Tank-Type Dense Phase Pneumatic Transporter

Attrition of granules by a blow-tank-type dense-phase pneumatic transporter was investigated. Experiments were conducted by the pneumatic transporter using a shot-type-feed method that facilitated the accurate analysis of attrition by conveying lumps of granules one at a time. The tests were performed using granulated material with high bulk density, which is persistently subject to high attrition during conventional pneumatic transport regardless of various countermeasures. The pneumatic transporter was operated under conditions that minimized granule attrition. The following results were obtained: (1) granule attrition in the feeding portion increased with the feed tank pressure, (2) fine particle fraction was linearly increased with the number of bends and transport length, whereas it increased proportional to the 2.6th power of air velocity, and (3) granule attrition was high especially under conditions that were likely to cause chocking in the pipeline.