Improving Scale Up Procedures for Solids Friction and Minimum Transport Boundary for Fluidized Dense Phase Pneumatic Conveying Systems

Abstract

This thesis presents results of an ongoing investigation into developing a validated modeling procedure of important design criteria, such as solids friction factor (for the accurate prediction of pressure drop) and minimum transport condition for the fluidized dense-phase pneumatic conveying of powders. In spite of having the potential of being energy economic mode of pneumatic transport, reliable design of fluidized dense-phase pneumatic conveying systems is still a difficult task due to the highly turbulent and complex nature of the flow of fine powders under high concentrations, where it is difficult to model the particle-wall-air interactions. Major efforts in this thesis have gone to develop pneumatic conveying test facility at the Laboratory for Particle and Bulk Solids Technologies, Thapar University, India for the fluidized dense-phase flow of fine powders having different pipeline configurations, such as 43 mm I.D. × 24 m long, 54 mm I.D. × 24 m long and 69 mm I.D. × 24 m long and 54 mm I.D. × 70 m long pipes. Indian fly ash was conveyed in fluidized dense-phase. Additional tests (under scale-up condition) were performed by conveying of cement and a different sample of fly ash through the 65 mm I.D × 254 m long and 80/100 mm I.D × 407 m long test rigs of Fujian Longking Co., China. Existing data of other researcher (from the laboratory of University of Wollongong, Australia), where ESP dust and fly ash were conveyed through 69 mm I.D. × 168 m long, 105 mm I.D. ×168 m long and 69 mm I.D. × 554 m long pipelines, were also used for comprehensive scale-up validation of the developed models. A new technique of modeling solids friction factor has been developed using new dimensionless numbers, volumetric loading ratio and dimensionless velocity (the ratio of particle free settling velocity to superficial conveying air velocity) by replacing the solids loading ratio and Froude numbers, respectively, present in the existing models.