Developments on software tools for data acquisition and numerical simulation for gamma-ray scanning

The gamma-ray scanning technique is widely used for evaluating the operating characteristics of distillation columns considered as the most critical components in petrochemical plants. Gamma-ray scanning provides essential data to optimize the performance of the columns and to identify maintenance requirements. New and more efficient data acquisition and processing software has been developed for Gamma-ray scanning. This new software permits to conduct gamma scanning explorations with all necessary information concerning the columns directly incorporated in the software. New features help a lot to interpret on-line the obtained results. A first version of the new data acquisition and processing software has been successfully tested in real conditions of utilization. For enhancing the interpretation of the experimental results of the technique, Geant 3 and Geant 4 Monte carlo simulation tools, developed at the CERN, have been used, to help identifying any possible malfunction inside a column and providing specific information, as a level liquid on a tray. In this study, the Geant simulations are performed for a distillation column. A set of parameters, principally the source energy (
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Co) and the source-detector separation are fixed. Also many simulations were carried out to prove that there is no effect of the distillate chemical composition on the obtained results. To assure that the code runs correctly, a number of simulations were done to reproduce a density profile in the ideal case (no malfunctions in column). The distillation column process malfunctions that have been examined were principally liquid entrainment and weeping between trays. These phenomena were modelled by varying the thickness of the liquid layer on and under the tray.