Process Imaging: What Industry Wants

David M. Scott

DuPont Central Research & Development, Wilmington, Delaware 19880-0304 USA

Process imaging is the art of visualizing the changes occurring inside an industrial process. A number of techniques (including tomography and other approaches) have been applied to measurement needs in the chemical industry. Application areas include polymer compounding, polymer extrusion, crystallization, granulation, media milling, and filtration. Polymer compounded with glass fiber is evaluated by a radioscopic technique to measure concentration and dispersion uniformity of the glass. In-process cameras are used to detect contamination in extruded molten polymer and to monitor crystallization in production-scale reactors. Granulation is controlled by at-line measurements of granule size obtained from image processing. Tomographic imaging provides feedback for improved operation of media mills and filters.

These and other applications have been relatively successful for a number of reasons that they hold in common: They provide necessary data that could not otherwise be measured. The data is relatively straightforward to analyze, and it relates directly to physical properties that have commercial importance. The measurement (or sensor) can easily be integrated with the existing process. The instrumentation (both hardware and software) is sufficiently flexible to be adapted to similar measurement applications without further development work. Some progress has been made towards these goals, but there is clearly additional work to be done.

Process imaging, including process tomography, can provide essential information about industrial processes. Acceptance of such techniques will continue to grow as additional success stories are made public. In the meantime, tomographers should focus on those application areas where they can meet the expectations listed above.