PTQ Q3 2025 Issue

The new technology creates additional surface roughness

Created surface roughness

115

TK-44X SiliconTrap TK-46X SiliconTrap

Solid Liquid

110

Unetched surface TK-441/447 SiliconTrap

Etched surface TK-461/467 SiliconTrap

105

100

HDS

HDN

carrier, so it is necessary to normalise out this silicon in the spent catalyst analysis. Improve silicon pick-up TK-400 series SiliconTrap catalysts have played a role in the coker naphtha market for more than 25 years. The initial sil- icon trap catalyst series was improved in 2016 and named TK-44x SiliconTrap by enhancing the alumina formulation with higher surface area and better physical properties to improve the silicon pick-up. In late 2024, the new-genera- tion TK-461 SiliconTrap and TK-467 SiliconTrap catalysts were launched with a further increased surface area per volume. The selection of the optimal SiliconTrap catalyst should be based on the type of siloxane size present in the coker naphtha stream, as shown in Table 3 . Examples of the dis- tribution of ‘D’ siloxanes molecules in light (see Figure 4 ) and heavy coker (see Figure 5 ) naphtha detected by atomic emission detection (AED) are also displayed. Increased catalyst surface area and roughness Enhanced surface roughness plays a critical role in pro- moting metal dispersion by providing numerous anchoring points, which leads to a more uniform distribution of the active components across the catalyst. This uniformity not only boosts catalytic activity in key reactions such as HDS and HDN, but also optimises overall reaction kinetics by increasing the contact between the feed molecules and the active sites. The increased roughness provides additional surface area for silicon uptake per reactor volume, enabling the catalyst Figure 6 Newly developed Topsoe technology for enhanc- ing alumina roughness

to capture and retain silicon contaminants more efficiently. By providing more sites for silicon binding, the catalyst can sustain its activity over extended cycle lengths, thus reduc- ing downtime and operational costs. In summary, the controlled increase of surface area and roughness significantly boosts the catalyst’s capacity for silicon pick-up and the catalyst activity. This dual bene- fit is fundamental to achieving higher overall efficiency, improved process reliability, and an extended catalyst life in refining applications. Furthermore, the additional roughness ensures mark- edly improved contact with feed molecules. This is clearly demonstrated in the comparative figures showing the unetched surface vs the etched surface, along with a photo of its actual appearance (see Figure 6 ). The top left image shows the older TK-441/447 SiliconTrap generation with a non-etched surface. The right image illustrates the new and enhanced TK-461/467 SiliconTrap product, where the intentionally etched surface greatly contributes to the over- all performance improvements. The new formulation pro- vides an enhanced surface area, resulting in a significant increase in the silicon pick-up per volume. In addition to the demonstration of the enhanced silicon pick-up via canister installations, comprehensive pilot test- ing was conducted at Topsoe’s R&D facilities to evaluate the hydrotreating performance of the TK-46x SiliconTrap products relative to the prior-generation products. The results, listed in Figure 7 , show that the advanced formulation of TK-46x SiliconTrap products provides nota- ble enhancements in both HDS and HDN activities. The HDN performance improved by 8-13%, while the HDS activity increased by approximately 5-7% when compared to the prior-generation products. The technical value proposition of these enhancements lies in the strategic flexibility they offer. With the improved cata - lytic activity and enhanced surface area per volume, refiner - ies can now redesign the catalyst loading more efficiently by either maximising bulk catalyst loading to process more bar- rels or processing feeds with higher silicon concentrations. Higher silicon capacity together with higher catalyst activity will increase the profitability of any coker naphtha unit. Figure 7 Average HDS and HDN activity in TK-46Xs SiliconTrap

Value proposition

Benefit

Inc rease in silicon uptake (or throughput) for the same cycle length Extended operating cycle

Significantly higher silicon pick-up for the same cycle

Longer cycle length due to better HDS, HDN, and Si pick-up

Table 4

PTQ Q3 2025