(409d) Effect of Feed Frame Design and Operating Parameters On Powder Residence Time Distribution (RTD)
AIChE Annual Meeting
Measurement, Monitoring and Characterization Methods for Particulate Systems Research in Powder and Granular Mixing
Wednesday, November 10, 2010 - 9:45am to 10:10am
Powder compression in rotary tablet presses is used as a major step in the manufacture of pharmaceuticals, cosmetics, catalysts, personal care products, military ordnance, etc. The value of all products manufactured by compression operations is enormous; just for pharmaceuticals, more than 70% of all pharmaceutical products sold worldwide are tablets, having an estimated market value in excess of $300 B/yr. In all of these manufacturing processes, consistent filling of the tablet press die with a uniform weight of powder is often both critical to quality and rate-limiting for the entire process, and therefore, uniform die filling is a crucial control variable. The amount of powder entering the die prior to compression determines the weight of the compressed product unit, and for pharmaceutical products, the overall drug content of individual tablets. Powder flowability is affected both by powder material properties and by the equipment used for processing the material. In powder compaction applications, consistent flow of powders into the small die of a tablet press is key to producing tablets with consistent properties. Manufacturers often use mechanical devices, called ?feed frames? or ?feed shoes? to maintain an adequate supply of powder to fill the dies of the tablet presses. The scope of this project includes the development of effective methods and equipment for continuous feeding of pharmaceutical powders as well as to investigate processing conditions and their powder effects. Through the use of experimental results and DEM simulation, powder phenomena and feeding performance for the two different feed frames (the Manesty Beta Press and the Fette 3090) with different production scale will be investigated. The experimental part includes the residence time distribution (RTD) measurements, the RTD correlation with the shear applied and the RTD and shear-strain effect on powder property changes for un-lubricated and lubricated materials with Acetaminophen or Naproxen Sodium. The experimental data were used to validate the simulation results using the RTD function. After validated the simulation methodology the result were used to understand more fundamentally the powder phenomena inside the feed frame and the contribution of each exit point to the amount of powder in dies.