Hybrid loading of regenerated and fresh catalyst for a lower carbon footprint (RI 2023)
Catalysts are typically one of the largest controllable costs for a refiner. Reusing properly regenerated catalysts avoids unnecessary spending and complements environmental sustainability.
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A pool of reusable catalysts is a valuable resource for refiners to manage their fill costs and precious foreign exchange. The reuse of catalyst does not only reduce the cost, but also reduces the CO₂ footprint significantly.
Hybrid loading is a practice followed by many refiners in which the reactor is loaded with fresh catalyst (at the bottom) and regenerated/rejuvenated catalyst (at the top). Hybrid loading renders almost similar performance with significant cost savings and very negligible/no performance.
The idea of hybrid loading is to combine regenerated catalyst at the top of the reactor and fresh catalyst at the bottom. In the top bed, no complex reactions occur, so catalyst activity does not hamper the performance of the unit. The highly reactive sulphur species with high reaction rates of removal at the top of the reactor are not limited by catalyst activity. Therefore, regenerated catalysts are good enough to provide the needed activity at the top of the reactor. Higher activity is required as the feed progresses through the unit, so fresh catalyst is loaded in the bottom beds (see Figure 1).
Figure 2 will help in understanding the benefits of hybrid loading. In hybrid loading (Case 2), one is likely to save total cost by >15% and able to reduce CO₂ by 24% reduction in carbon footprint. When calculated mathematically for Case 2, it might appear that there is a loss of activity (10 units). However, when actual RVA is actually measured in a simulation plant, it is observed that RVA remains the same for both cases. The reason for this unchanged overall activity is that one does not need a 100% new-generation active catalyst in the entire reactor system. As mentioned earlier, in the top bed of the reactor, a simple reaction occurs. So, a little lower active catalyst is good enough to act there. In the bottom part of the reactor, a difficult reaction occurs, so one needs a highly active catalyst there. So, Case 2 does not have any impact on cycle length and unit performance but results in cost saving and CO₂ footprint saving.
Economical and sustainable
Hybrid loading is well-proven practice through years of experience by many refiners, which cost-effectively maximises the performance of the unit. Hybrid loading is also supported/guaranteed by catalyst manufacturers. Hybrid catalyst loading is an economical and sustainable approach to drive profitability and promoting circular economy.
This short article originally appeared in the 2023Refining India Newspaper, which you can VIEW HERE
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