Doctor of Philosophy
Chemical and Biochemical Engineering
Dr. Lauren Briens
The pharmaceutical manufacturing process consists of a number of batch steps; each step must be monitored and controlled to ensure quality standards are met. The development of process analytical technologies (PAT) can improve product monitoring with the aim of increasing efficiency, product quality and consistency and creating a better understanding of the manufacturing process.
This work investigates the feasibility of using passive acoustic emissions (PAE) to monitor particulates in a V-blender. An accelerometer was attached to the lid of a V-blender to measure vibrations from the tumbling solids. A wavelet filter removed the oscillations in the signals from the motion of the shell, focusing on the emissions from the particle interactions. The particle size, fill level and scale affected the acoustic emissions through changes in the particle momentum. Changes in particle cohesiveness and flowability were also reflected in the measured emissions.
Powder properties and behavior are critical to efficient and successful manufacturing of pharmaceutical tablets. As the powders must be transferred between the different manufacturing stages, the flowability of powders is critical. Trials were conducted to investigate the effect of moisture content of a powder on its flowability. Through avalanche behavior, it was found that the flowability and the dynamic density of a powder change with moisture content.
PAEs were used to detect changes in solids moisture content as solids tumbled within the V-blender. It was found that particle mass, coefficient of restitution (COR) and flowability impacted the amplitude of the acoustic emissions. To further investigate the effects of particle flowability, PAEs were used to monitor lubricant addition. The amplitudes of the acoustic emissions were sensitive to the lubricant addition due to changes in the flowability. A trend in the emission amplitude allowed for the progression of the lubricant mixing to be followed. Overall, the research supports the feasibility of PAEs as a PAT for mixing in a tumbling blender to increase process knowledge and improve product quality.
Crouter, Allison, "Passive Acoustic Emissions in a V-blender" (2016). Electronic Thesis and Dissertation Repository. 3858.