(247d) Dilute Phase Pneumatic Conveying of Blended Plastic Pellets

The pneumatic conveying of plastic pellets is a process widely used in the chemical industry. Different products can be transported using the same conveying system thanks to the great flexibility that this technology offers. However, there are also challenges due to the significant variation on pressure drop produced by different products. This has a direct impact on the conveying capacity due to the limited pressure that the air mover can provide. Among the different types of plastic pellets, it is known that products with higher modulus of elasticity tend to produce higher pressure drop than harder materials. The present work explores the effect of blending hard and soft pellets, on the pressure drop during dilute phase pneumatic conveying. With this purpose, a series of conveying tests were performed with blends of two plastic pellets in different proportions. The component pellets had similar size, shape and density but different modulus of elasticity. The blends were conveyed through a 52 mm diameter aluminum pipe and 35 m length approximately. Measurements of pressure drops were performed in straight sections and across elbows. Additional tests were performed with the plain materials in order to obtain control data. Using the pressure drop, the friction factors were calculated for each blend as well as for the plain materials.