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To address the issue of reducing sulfur content, major oil companies around the world have made many efforts. These efforts are reflected not only in significant breakthroughs in new hydrogenation catalysts and process technologies, but also in the development of new internal components for hydrogenation reactors. Advanced internals in hydrogenation reactors can keep the radial temperature difference across the catalyst bed at around 3°C. When designing a new reactor or modifying an existing one, two basic principles are generally followed: (1) maximizing the catalyst capacity within the reactor ； ⑵Maximize the utilization rate of the catalyst. The proper selection and design of internal reactor components can maximize the mixing of reactants (gases and liquids) and ensure the effective utilization of the main catalyst. In a hydrogenation reactor, the catalyst utilization can be maximized if the gas and liquid reactants achieve a uniform distribution in terms of mass and temperature before reaching the very top of each catalyst bed. Whether the functions of new catalysts and new processes can be fully utilized is closely related to the performance of internal components in the reactor. In other words, the effectiveness of the internal components also directly affects the catalyst life, product quality, and the operating cycle of the facility. In the production of clean fuel oil, the results achieved by employing a good set of internal component technologies are no less effective than switching to a catalyst with higher activity. TOPSOE’s reactor internals technology. The first step toward achieving this goal is to reform the graded bed technology. A specially designed inert top-bed material was adopted, and a highly active cyclic TK catalyst was developed to replace the inert spheres commonly used in the top bed of catalysts within hydrogenation reactors. The porosity of Topsoe inert material is 53-55%, whereas that of ordinary inert balls is only 33%. Furthermore, the use of various active cyclic TK catalysts in place of inert spheres provides more active contact surfaces, thereby enabling good control of the bed pressure drop. Topsoe’s reactor internals technology: Topsoe has developed vapor-lift type distribution plates. The smaller the spacing between the distributors, the greater the number of droplets, which indicates that the liquid can achieve a good level of dispersion on the surface of the catalyst bed more quickly ； The levelness of the trays must be carefully considered to ensure that the liquid does not fall only from certain distribution points. To ensure that the liquid flows evenly through all distributors, the issue of blockage caused by coke formation and corrosion products must also be taken into account. The advantages of Topose’s liquid distribution tray in TOPSOE’s reactor internals technology are that, compared to the bubble cap design, the base of the distributors on this tray is much smaller, allowing for more dropping points to be provided near the reactor walls. Since the catalyst near the reactor wall is fully utilized, the **overall performance of the catalyst can be improved. In most cases, this is equivalent to a 25% increase in the total reactor inlet surface area. After using the “air-lift” distribution plate, the average temperature in the reactor decreased by 20°F due to a significant increase in the number of drip points. The advantage of the Topose liquid distribution tray is that the distance between the distributors on it is small; in other words, the distance between the outermost distributor and the reactor wall is small, which reduces the likelihood of hot spots forming. In many cases, end-of-life operating conditions depend on the maximum temperature of the reactor. If a consistent radial temperature can be maintained, the operating cycle can be significantly extended. Utilizing Shell International Consulting’s latest reactor design can increase the volume utilization rate of the reactor from 65% to 86%. The end result is a more than 30% increase in catalyst activity, along with a reduction of over 12°F in the initial operating temperature ； Second, it can maximize the catalyst utilization rate. The highly dispersed (HD) distributor plates and ultra-flat quench plates (UFQ) developed by Shell International Consulting, combined with the use of their proprietary HD nozzles, enable the catalyst utilization rate in trickle-bed reactors to approach 100%. The shell internals can increase the catalyst utilization rate from 80% to nearly 100%, with the resulting improvement equivalent to a 25% increase in HDS activity or a 10°F reduction in the initial operating temperature. Luoyang Petrochemical Engineering Company’s reactor internals technology has developed L-type gas-liquid distributors and L-type quench tanks. The BL-type distributor and BL-type quench tank were developed for the hydrogenation of high-viscosity oils. Shell’s internal component technology: Shell Global Solutions and CC&T have been partners for a long time. The new catalysts developed by Standard Catalyst Technology Company are always combined with the reactor design technology of Shell International Consulting Company when brought to market.