Fluidized dense phase pneumatic conveying: a review

The focus of investigations and research has been shifted in the past decade from conveying bulk materials in dilute phase flow at high velocity to dense phase flow at low conveying air velocity. Dense phase flow offers much less operational problems, such as wear and product attrition, and offers low specific power consumption. It, therefore, enhances the life of pneumatic conveying pipelines and associated components. However, the complete phenomenon of the flow mechanism of fine powder in fluidized dense phase pneumatic conveying has not been exactly explored. It necessitates an understanding of the flow behaviors of a fine powder, factors affecting the flow mechanisms, and approaches to model it. The present work describes the evaluation and assessment of the flow of fine powders in the fluidized dense phase. The performance of the pneumatic conveying system was based on modeling solids friction factor which was used for determining conveying line pressure drop. The predicted results provided by these approaches proved to be inaccurate compared to those of data collected from actual plants. Further, the numerical modeling methods to predict pressure drop for small length pipeline, difficulties, and recent progress in gas-solid prediction investigations are discussed as well. Finally, a Bypass dense phase conveying system which has many advantages over the conventional one has been presented.