Dynamic Imaging of Process Plant Reactors and Separators using Electrical Process Tomography

Abstract

The use of electrical tomography is beginning to find application in industrial processes as a measurement tool for modelling, model verification and on-line monitoring and diagnosis [1, 2]. The method employs simple sensors arranged on the periphery of process reactors that contact the process fluid. Electrical excitation allows to collect information that can be used to deduce the distribution of electrical properties (such as conductivity, or dielectric constant) within the reactor. These can in turn be related to reactant-product concentration profiles within the reactor, provided that such components exhibit inherent differences in electrical properties. A particular attribute of electrical systems is their ability to make measurements rapidly. The author reported the most recent developments in the application of electrical capacitance and electrical resistance tomography to a selection of process systems [3-5]. The objective was to illustrate the capabilities of the method. The rapid data collection process facilitates observation of kinetic processes. Laboratory and industrial studies of the following systems have been presented: - gas-liquid and liquid-liquid stirred tanks (tank design and scale up, mixing kinetics); - solid-liquid stirred tanks (tank design and scale up, crystallisation and precipitation); - gas-liquid bubble columns (flow monitoring and control of interfacial area); - solid-liquid cyclonic separators (fluid dynamic code development, on-line plant monitoring); - solid-liquid separation (cycle time in product washing); - autoclave polymerisers (reaction pathways and endpoints). Prospects for the integration of advanced visualisation and modelling tools with chemical reactor models have been discussed. Future goals were identified, including the possible use of chemical species mapping.