PTQ Q4 2026 Issue

Overlay comparison

Feedstock (SR diesel / LCO)

Benzothiophenes

Anilines/ indoles

DBT

4,6-DMDBT (Dibenzothiophenes)

TK-594 HyBRIM Conventional CoMo catalyst

Retention time (min)

DBT

Conventional CoMo catalyst

4,6-DMDBT (Dibenzo- thiophenes)

Thiophenes/ sulphides

Retention time (min)

TK-594 HyBRIM

Performance summary

Conventional CoMo catalyst Higher levels of refractory heterocycles TK-594 HyBRIM Superior removal of refractory heterocycles

Higher benzothiophenes

Higher DBT Higher 4,6-DMDBT

Si g nificantly lower benzothiophenes Signicantly lower DBT Signicantly lower 4,6-DMDBT

Retention time (min)

Data from GC-AED sulphur-selective analysis Retention time window optimised for heterocycle analysis

Figure 5 GC-AED sulphur selective detection on feed and product from conventional CoMo catalysts and TK-594 HyBRIM

Since the improved activity is obtained without increasing the catalyst deactivation rate, these operating advantages can be maintained throughout the commercial catalyst cycle, providing greater operational flexibility while preserv - ing ULSD product quality. Conclusion As ULSD hydrotreater feed pools incorporate increasing por- tions of LCO and other cracked streams, refractory nitrogen inhibition is expected to become an increasingly important limitation for ULSD production. Future catalyst development will require simultaneous optimisation of HDS activity, HDN capability, and active-phase architecture rather than focus- ing solely on intrinsic sulphur removal activity. The results presented here demonstrate that improved catalyst morphology and more efficient utilisation of hydrogenation functionality provide an effective strategy for maintaining deep sulphur removal under increasingly challenging commercial operating conditions. ULSD pro- duction is no longer constrained by sulphur chemistry alone. Refractory nitrogen compounds, particularly car- bazole-type molecules, are a critical factor in determining catalyst effectiveness, required operating severity, reactor utilisation, and ultimately refinery economics. The results presented here demonstrate that TK-594 HyBRIM addresses these challenges through superior removal of refractory nitrogen compounds while simultaneously enhancing the conversion of the most refractory sulphur spe- cies. Nitrogen-selective and sulphur-selective GC-AED anal- yses demonstrate substantially lower residual concentrations

of carbazoles, dibenzothiophenes, alkyl-dibenzothiophenes, and 4,6-DMDBT compared with conventional CoMo cata- lysts under identical operating conditions. Long-term pilot plant evaluation further confirms that these improvements are achieved without compromising catalyst stability, demonstrating that enhanced hydro- genation performance can be maintained throughout the catalyst cycle. The commercial benefits for refiners are sig - nificant. Additional HDS and HDN performance provided by TK-594 HyBRIM can be translated into higher through- put, processing of more challenging feedstock, greater vol- ume swell, longer cycle, or a combination of all of these to improve the profitability of the ULSD unit. HyBRIM and BRIM are marks of Topsoe. References 1 X. E. R. Maldonado, R. Jesina, M. Lutecki, Handling complex hydrocar - bon molecules, PTQ , Q4 2024. 2 S. Robledo, P. Zeuthen, More from the barrel, PTQ , Q2 2021. 3 P. Zeuthen, S. Robledo, Improved chemistry, improved catalysts, Hydrocarbon Engineering , November 2020. 4 H Topsøe, The role of Co-Mo-S type structures in hydrotreating cata- lysts, Applied Catalysts A: General, 2007 5 L. Skyum. Ultra-deep desulphurisation of gasoils. PTQ Catalysis 2003 . Xavier E. Ruiz Maldonado is Technical Service Manager within Topsoe North America and has more than 20 years of experience in technical support in hydrotreating and hydrocracking industrial operations for both the Americas and European refinery business. He holds an MS in chemical engineering from Simon Bolivar University in Venezuela and a petroleum studies degree from the French Institute of Petroleum. Email: xerm@topsoe.com

PTQ Q4 2026