Radioisotope Technology as Applied to Petrochemical Industry

Abstract

Gamma Scanning is the best technique to carry out an internal inspection of distillation columns, vessels and pipes without interrupting production. 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.Gamma Scanning is a very effective, well established, troubleshooting technique. This powerful diagnostic tool, which has been used for decades, has become popular as it allows inspection of the distillation column components without interrupting operation. In comparison to other non-destructive control techniques used in practice, gamma-ray scanning provides, in real time, the clearest vision of the production conditions inside a process reservoir. It is also cost-effective, particularly when compared to lost production ).Gamma scanning can help diagnose and solve approximately 70% of column problems encountered at refinery and petrochemical sites. For other cases, it allows resources to be www.intechopen.com Petrochemicals 154 focused on finding the true source of the problem by eliminating inadequate possible scenarios. It provides essential data to optimize the performance, track any deteriorating effects and identify the maintenance requirements of a distillation column so that it significantly reduces repair downtime (Alami, 2009). Main problems met on distillation columnsThe hydraulic capacity of trayed distillation columns is always limited by either a high liquid entrainment, or by an overload of downcomers. The technology of high capacity trays deals with these two fundamental limits by reducing the entrainment or by releasing the loads of downcomers. Both are generally connected ). Liquid entrainmentThe entrainment can be defined as the physical rise of droplets, provoked by the ascending flow of vapour. The vapour tends to hoist droplets upward, while the gravity tends to pull them downward. If the vapour speed is relatively high, then the entrainment can surpass the gravity and some droplets can be transported from a tray to the tray above. The entrainment can be also seen as the excessive accumulation of liquid on trays, which is led by the ascending transport of liquid from a tray to the other one by the current of ascending gas.A high liquid entrainment can lead directly to a column flooding called "flooding jet". It can also end in it indirectly by increasing the liquid load until reaching the limit of the downcomer, putting in danger the efficiency of separation. Consequently the reflux flow of the column is increased, increasing more the global liquid flow.The devices of contact between liquid and vapour in the distillation and absorption columns which we meet most generally are trays with sieves and with valves and, in a more or less large extent, of trays with bubble caps. The capacity of retention of these trays is mostly limited by the p...

Gamma Photon Column Scanning of Prototype and Industrial Distillation Columns

“…Gamma column scanning is a non-invasive and non-destructive technique used for internal inspection of the column along its height and is not affected in any way by temperature and pressure [4]. This technique is safer than radiographic applications as the intensity of the sealed source is only 0.1% of the intensity used to test welds by radiography methods [1].…”

“…The gamma ray source should have enough energy to penetrate the column thickness and the material inside the column. The widely used gamma ray sources are 60 Co (1.33 MeV and 1.17 MeV) with a half-life of 5.27 years and 137 Cs (662 keV) with a half-life of 30 years [4]. The required activity for a gamma source for scanning a distillation column depends on the diameter and the shielding material of the column and the energy of the gamma source itself [3].…”

“…Gamma column scanning provides essential information that can be used to track any deteriorating effects, optimize the performance and identify maintenance requirements of distillation columns well in advance before scheduled maintenance shutdown. It gives engineers and operators an insight into the needed spare parts in the next scheduled maintenance shutdown enabling them to avoid ordering spare parts on an emergency basis, which is costly thus reducing repair downtime and costs [4].…”

Design, optimization and performance of source and detector collimators for gamma-ray scanning of a lab-scale distillation column

“…Several types of collimators can be used for both the source and detector, but the panoramic and pinhole collimators for the source and pinhole collimator for the detector are the most widely used ones (Alami and Bensitel, 2012;IAEA, 2008).…”

Improving the efficiency of high-temperature processes for producing lower olefins via deep-processing of by-products

“…At present, in Russia it is both necessary and possible to produce new products based on existing industry, thus combining the large-capacity and high-tech chemistry [45,46]. Variants of complex processing schemes of liquid pyrolysis products provide for the allocation and use of large components or the re-processing of whole fractions into limited numbers of products with reproducible physical, chemical, and technical characteristics [47,48].…”