Pneumatic Conveying Characteristics of Fine and Granular Bulk Solids

Abstract

Fine and granular products possess significantly different pneumatic conveying characteristics. Fine products usually have smooth conveying characteristic curves from dilute- to dense-phase. Between dilute- and dense-phase there is a pressure minimum curve. However, when granular products are conveyed between dilute- and dense-phase, significant fluctuations in pressure and vibration can occur along the pipeline. To obtain reliable operating conditions for the designed pneumatic conveying system, three semi-empirical correlations are developed in this paper for the calculation of the pressure minimum curve for fine powders and the boundaries between dilute-phase, unstable-zone and dense-phase flow for granular products in terms of particle properties and conveying conditions. Finally, a new procedure is presented for the prediction of total pipeline air pressure drop and the economic design of pneumatic conveying systems with the aim of reducing power consumption and particle damage.