For a typical U-tube exchanger with two tube passes, 0.75-inch tubes on a 1-inch rotated…
Reactor Internals by Shell
Application: A suite of proprietary reactor internals that offer uniform gas and liquid distribution to increase catalyst utilization and efficiently quench highly exothermic hydroprocessing catalytic reactions. The stateof-the-art reactor internals take up less space, thus enabling high reactor volume utilization while helping maximize catalyst run length. The designs are simple and robust and allow easy access to the reactor and efficient maintenance and catalyst change-out activities.
Description: Shell Global Solutions’ high-dispersion (HD) trays help to optimize catalyst utilization by achieving highly uniform vapor–liquid distribution and excellent thermal distribution. Each tray nozzle is customized so that gas flow momentum is used to disperse the liquid into a mist of small droplets. This operating concept differentiates the technology from conventional downcomers or bubble caps because the nozzles fully and uniformly wet the entire catalyst surface and make efficient use of the top part of the catalyst bed.
Our reactor internals system also includes the following technology:
• Top-bed scale-catching trays to trap fouling material and prevent it from entering the catalyst beds
• Ultra-flat quench (UFQ) interbed internals for uniform process and quench mixing at the interbeds
• Catalyst support grids
• Compact bottom baskets to help maximize the catalyst volume in the bottom domes.
• Activity—Shell Global Solutions’ reactor internals can produce 30% –50% activity gains through improved catalyst utilization and extra volume for loading catalyst.
• Efficiency—HD trays can help to utilize nearly 100% of the catalyst inventory.
• Operating window—HD trays offer high flexibility of feedrate: typically +50% to –70% for liquid as well as gas.
• Anti-fouling capacity—Shell Global Solutions’ top-bed filters can efficiently remove fouling materials yet take up virtually no valuable reactor volume
• Robust design—Nuts and bolts are not used for any fixing. We offer global manufacturing options, and units are designed to withstand tilting and fouling.
Business value: The HD tray results in improved liquid and thermal distribution, so ensuring maximum use of the catalyst bed. Refiners may double their cycle lengths as a result of using the new tray. These longer cycle lengths are due to the slower catalyst deactivation; the lower inlet temperatures required to produce high-specification products; and the better thermal distribution that the HD trays offer. The anti-fouling trays have resulted in increases in cycle length of up to 200%.
Installation: All Shell Global Solutions’ internals have been commercially proven through more than 230 hydroprocessing applications.
A South Korean refiner was experiencing hot spots in the catalyst beds of its lube-oil hydrotreater. Shell Global Solutions and its affiliate Criterion Catalysts & Technologies worked together to resolve the problem. HD trays were applied in combination with UFQ interbed internals to improve quenching and mixing between the catalyst beds. As a result, catalyst utilization improved significantly, and helped to facilitate a longer cycle and more severe operation.
Shell Global Solutions and Criterion Catalysts & Technologies tailored a system for JSC Naftan refinery when it converted a hydrotreating reactor for use as a mild hydrocracker. The system incorporated stateof-the-art internals and new-generation pre-treatment and cracking catalysts. The revamped unit was able to achieve conversion of the 370°C+ vacuum gasoil fraction at levels up to 50% higher than the design target.
Licensor: Shell Global Solutions International B.V.
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