Process tomography for identification, design and measurement in industrial systems

Abstract Process tomography will improve the operation and design of processes handling multicomponent fluids by enabling the boundaries between different components in a process to be imaged in real-time using non-intrusive sensors. Information on flow regime, vector velocity and component size distribution will be determined from the images, thus providing systems for multicomponent flow measurement and information relevant to determining the heat/mass transfer properties of systems. The need for tomographic imaging in industry is analogous to the medical need for body scanners, which has been met by the development of computer-aided tomography. The basic idea is to install a number of non-intrusive sensors around the pipe or vessel to be imaged. The sensor output signals depend on the position of the component boundaries within their sensing zones. A computer is then used to reconstruct a tomographic image of the cross-section being observed by the sensors. Process tomography will provide, for instance, identification of the distribution of mixing zones in stirred tank reactors, interface measurement in complex separation processes and measurements of two-phase flow boundaries in pipes with applications to multi-component flow measurement. A system has been successfully demonstrated which uses non-intrusive capacitance sensors and a transputer for image reconstruction, giving a cross-sectional image of an oil/water flow in a 75 mm diameter pipe in real-time.