(402d) Powder Feeder Pairing with Downsteam Continuous Mixer

In pharmaceutical powder handling, as well as other continuous powder processing industries, the challenge to consistently feed powder can be one of the most important parts of the overall processing.  Inconsistent flow from a powder feeder can lead to inconsistencies in subsequent unit operations, such as mixing.  There are methods to improve feeding consistency, but due to the intrinsic nature of powder, feedrate variability cannot be entirely removed.    The dilemma then arises of what is an acceptable level of variability for the process.

The focus of this work is developing a method to pair a subsequent unit operations with a powder feeder or vice versa.  By using pulse experiments to determine the characteristic residence time distributions (RTD) of a mixer, it is possible to develop a transfer function model that can be used to predict the effect of fluctuations and/or setpoint deviations in an inlet feed stream.  By changing the configuration or design of either the mixer or feeders, it is possible to greatly improve overall performance of the feeders-mixer system.