Electrical impedance tomography (EIT) has significant potential as a noninvasive tool for spatially resolved process monitoring, yet most reported systems remain laboratory prototypes and are rarely suitable for integration into chemical engineering environments. In this work, the authors present a fully embedded, low-cost EIT platform designed as a deployable tomographic sensor for the in situ monitoring of reactive media in laboratory-scale reactors. The platform can be realised for approximately 442 US dollars in prototype quantities and below 310 US dollars in small-batch production. It enables spatially resolved conductivity mapping with 32 measurement channels and is designed for straightforward integration into laboratory and reactor environments.
The compact USB-powered hardware is complemented by microcontroller firmware written in C and an object-oriented Python interface for experiment control and data analysis, while on-board impedance calculation allows stand-alone operation and supports the real-time monitoring of dynamic conductive processes. The hardware characterisation includes measurements of total harmonic distortion plus noise for signal excitation and voltage measurement with mean values up to 0.0651 percent, a signal frequency of 105 kilohertz, a variable analogue filter gain ranging from −1.35 to 34.81 decibels, and characterisation of the current source at excitation currents of 100 and 350 microampere.
The performance of the system was validated for the adjacent and the opposed pair pattern, achieving a mean signal-to-noise ratio of up to 76.59 decibels, with imaging performance quantified on circular phantoms in terms of position error, spatial resolution and detection limit. Long-term stability was verified over a 20 hour measurement with a relative drift below 0.03 percent, and the system achieves frame rates of 7.36 to 13.18 frames per second depending on the measurement pattern. In a chemically relevant scenario, the platform monitored the dissolution of a 5 molar sulfuric acid solution, where the resulting spatial conductivity maps resolved transient concentration gradients associated with proton activity. Together, the characterised hardware performance and this validation establish the platform as a scalable in situ imaging sensor suitable for integration into adaptive, data-driven reactor systems.
The study was carried out at Hamburg University of Technology within the Collaborative Research Centre CRC 1615 (SMART Reactors).
Tom Liebing, Hossein Ostovar, Moritz Hollenberg, Dennis Kähler, Thorsten A. Kern (2026). A Cost-Efficient Electrical Impedance Tomography System for Adaptive Process Analytics. Ind. Eng. Chem. Res. 65 (31), 16739-16752.
