(509a) A Piecewise Parametric Model for Open Loop Screw Feeder Flow Rates
- Conference: AIChE Annual Meeting
- Year: 2019
- Proceeding: 2019 AIChE Annual Meeting
- Group: Pharmaceutical Discovery, Development and Manufacturing Forum
Wednesday, November 13, 2019 - 12:30pm-12:51pm
This work proposes a novel parametric piecewise-linear model to approximate the mass flow rate of powder discharged from a feeder under open loop operation. The piecewise model represents two flow regimes: a constant flow observed at higher powder masses in the hopper and a linearly declining flow observed at lower powder masses. First, a custom process model was developed in gPROMSâ¢ (Process Systems Enterprise, London, UK). Then, open loop experiments were performed using six different powders, two different Coperion K-Tron screw feeders, and multiple different motor speeds. Using the feederâs operational data, parameter values for each run configuration were estimated. It was observed that for powders that mirrored our models assumptions, the model was accurate over the entirety of the run. For powders that did not display strictly constant mass flow in the first regime, the model would instead capture the average mass flow rate. Overall, this model is easily fit, computationally inexpensive, and reliably describes the general open loop flow behavior of a powder. It is suitable for use in the early stages of CM process development.
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