Towards in-situ characterisation of formulated products

Abstract

Recently, the ability to characterise a formulated product during its manufacture has become very desirable due to the importance of maintaining control over its structure and electro-mechanical properties. The fields of process tomography and spectroscopy are set to play an important role in new technologies yielding in-situ characterisation of a product during chemical processing. This study has investigated such techniques with the aim to apply these tools to a relevant Johnson Matthey manufacturing line.
Water, being a high di-electric, can be detected at very low concentrations using Electrical Capacitance Tomography (ECT). This relationship has been exploited to monitor drying and phase boundaries of a packed bed in both two and three dimensions. A comparison with MRI has yielded similar results for the drying profile of a similar packed bed demonstrating technique robustness. Electrical Resistance Tomography (ERT) has been used to discriminate gas and solid phases within a three phase system. The measured conductivity of the multi-phase system at 300 Hz is different than at 9600 Hz and allows for the identification of conductive particles from air bubbles. The application of wideband impedance spectroscopy to ceramic suspensions has shown that electrical and structural properties are inter-related.
This work has driven forward the research and improved the range of applications of electrical process analytics.