(458g) Automatic in-Line Electrode Fault Detection Via Optical Coherence Tomography

Electrochemical processes are an important part of the production of active pharmaceutical ingredients (APIs). Faults of the electrode, such as corrosion or fouling, have a significant impact on the process performance. In severe cases, they can damage the electrode beyond repair and halt the conversion. In-line or operando monitoring of electrochemical processes have been established as an important link to process performance [1-6]. In the present work, a new method for direct electrode monitoring via optical coherence tomography (OCT) is presented. Due to the low wavelength interferometry that OCT is based on, some materials, such as particles, can be penetrated and will appear semi-transparent in the resulting 3D volume scans. On the other hand, corrosion bubbles as little as 20 µm in height on the electrode are already visible on the images. During the electrochemical process, scans of the surface of the electrode are taken via OCT and the resulting images are automatically evaluated. During the evaluation, the upper boundary of the surface is extracted and an idealized mathematical extraction model is computed. This enables the automatic classification of irregularities on the electrode, such as corrosion peaks or particles sticking to the electrode. The developed OCT technology allows for continuous monitoring and automatic real-time evaluation of the resulting images. Hence, the results from OCT can be used for a real-time control strategy aimed at improving and optimizing the electrochemical process.

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