PTQ Q4 2026 Issue

100 140 180 260 220 300 400 105 110 115 125 130 120 135 105 110 115 125 130 120 135

Indoles

Anilines

Carbazoles

High carbazole content High product nitrogen

Minutes

80% reduction of carbazoles Lower product nitrogen

Carbazoles

Minutes

98% reduction of carbazoles Lower product nitrogen

Carbazoles

Minutes

Figure 4 GC-AED nitrogen selective detection on feed and product from conventional CoMo catalysts and TK-594 HyBRIM

Removal of refractory carbazole species reduces com- petitive adsorption on hydrogenation-active sites, allowing these sites to participate more effectively in hydrogena- tion-assisted sulphur removal. The benefit therefore extends beyond improved HDN performance and directly contributes to lower concentrations of refractory sulphur compounds in the product. The sulphur chromatograms presented in Figure 5 provide direct analytical evidence of this relationship. The improved nitrogen conversion demonstrated in Figure 4 is directly reflected in the sulphur-speciation results obtained by gas chromatography-atomic emission detection (GC-AED) using sulphur-selective detection under identical operating conditions. Since both catalysts were evaluated using the same feedstock and operating conditions, the observed differences in sulphur chromatograms can be directly attributed to catalyst performance rather than feed variability. The reduction in refractory sulphur compounds confirms that improved removal of carbazole species preserves hydro- genation functionality throughout the catalyst bed, thereby promoting more efficient conversion of sterically hindered sulphur molecules. Figure 5 shows how TK-594 HyBRIM consistently produces significantly lower residual concentra - tions of refractory sulphur compounds. The chromatographic overlay clearly demonstrates reduced concentrations of dibenzothiophene (DBT), alkyl-dibenzothi- ophenes, and particularly the highly refractory 4,6-DMDBT. These sulphur species are well recognised as among the most difficult molecules to convert during ULSD production and frequently determine EOR catalyst performance. The value of a hydroprocessing catalyst is not defined

solely by its fresh activity under favourable laboratory condi- tions. While many catalysts can demonstrate excellent initial performance on selected feedstocks or during short-dura- tion evaluations, commercial success depends on maintain- ing deep HDS performance throughout the catalyst cycle under increasingly demanding refinery conditions. Many ULSD units process feedstocks containing refrac - tory sulphur compounds together with elevated concentra- tions of refractory nitrogen species, often while operating under moderate hydrogen partial pressure and high space velocity. Long-term pilot plant testing demonstrated that TK-594 HyBRIM maintained the same deactivation rate to conventional CoMo catalysts while simultaneously pro- viding greater HDS and HDN performance, due to it being developed with a dispersed trimetallic active phase. This enables more effective utilisation of hydrogena- tion functionality under commercially relevant conditions, particularly when processing feeds containing elevated concentrations of carbazoles and other refractory nitrogen compounds. It allows for increased LCO blending, moderate hydrogen partial pressure, and high space velocity, all while meeting ultra-low sulphur diesel specifications. The commercial implications of this performance are sig- nificant because the additional HDS and HDN activity can be translated into several refinery optimisation opportunities depending on the operating objective. Refiners may choose to increase throughput, process more challenging feedstocks containing higher concentrations of cracked components, achieve greater product volume swell through increased aromatic saturation, extend catalyst cycle length, or combine several of these benefits simultaneously.

PTQ Q4 2026