The concept of 3D ECT system with increased border area sensitivity for crystallization processes diagnosis

• Published in: Sensor review Vol. 41; no. 1; pp. 35 - 45
• Main Author: Wajman, Radosław
• Format: Journal Article
• Language: English
• Published: Bradford Emerald Publishing Limited 24-02-2021; Emerald Group Publishing Limited
• Subjects: Algorithms; Construction; Crystal growth; Crystallization; Diagnosis; Electric fields; Electrodes; Image reconstruction; Iterative methods; Measurement techniques; Medical imaging; Permittivity; Potential fields; Process controls; Sensitivity; Sensors; Spectrum analysis; Systems analysis; Three dimensional imaging; Tomography; Ultrasonic imaging; X-rays; Electric field modeling; 3D ECT; Non-invasive imaging; Image reconstruction; Crystallization
• ISSN: 0260-2288; 1758-6828
• DOI: 10.1108/SR-10-2019-0254

Purpose
Crystallization is the process widely used for components separation and solids purification. The systems for crystallization process evaluation applied so far, involve numerous non-invasive tomographic measurement techniques which suffers from some reported problems. The purpose of this paper is to show the abilities of three-dimensional Electrical Capacitance Tomography (3D ECT) in the context of non-invasive and non-intrusive visualization of crystallization processes. Multiple aspects and problems of ECT imaging, as well as the computer model design to work with the high relative permittivity liquids, have been pointed out.
Design/methodology/approach
To design the most efficient (from a mechanical and electrical point of view) 3D ECT sensor structure, the high-precise impedance meter was applied. The three types of sensor were designed, built, and tested. To meet the new concept requirements, the dedicated ECT device has been constructed.
Findings
It has been shown that the ECT technique can be applied to the diagnosis of crystallization. The crystals distribution can be identified using this technique. The achieved measurement resolution allows detecting the localization of crystals. The usage of stabilized electrodes improves the sensitivity of the sensor and provides the images better suitable for further analysis.
Originality/value
The dedicated 3D ECT sensor construction has been proposed to increase its sensitivity in the border area, where the crystals grow. Regarding this feature, some new algorithms for the potential field distribution and the sensitivity matrix calculation have been developed. The adaptation of the iterative 3D image reconstruction process has also been described.