Effects of particle size distribution on particle entrainment in pneumatic conveying.

• Main Author: Goy, Sing Phang.
• Other Authors: Kunn Hadinoto Ong
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Science::Medicine::Pharmacy::Pharmaceutical technology
• Online Access: http://hdl.handle.net/10356/39945
• Institution: Nanyang Technological University

This report investigates the effects of particle size and particle size distribution on the minimum pickup velocity of the mono-sized glassbeads and the binary mixtures of glassbeads which are crucial in optimizing pneumatic conveying systems. Four major experiments were conducted on a setup of 2.05m long transparent acrylic pipe with an internal diameter of 0.0155m. It was retrofitted with a removable pipe section where compressed air with flowrates ranging from 20L/min to 62L/min flowed through upper hemispherical section to pick the glassbeads up from a loaded cavity in the lower hemispherical section. The materials used were mono-sized glassbeads with particle sizes of 50µm, 200µm and 400µm and three binary mixtures with varying mass ratios: 400µm and 200µm, 200µm and 50µm, 400µm and 50µm. The modified weight loss method was verified using the mono-sized glassbeads. It yielded consistent results with literature values which was a minimum point in the graph of minimum pickup velocity against the particle size. Prediction methods were developed to determine the minimum pickup velocity of the binary mixtures using the surface-volume diameter and the arithmetic mean diameter. It was observed that the minimum pickup velocity of the binary mixture increased either with increasing composition of smaller and cohesive particles or with increasing composition of larger and heavier particles. The results concluded that both particle size and particle size distribution affect the minimum pickup velocity through inertial and cohesive effects.