PTQ Q4 2024 Issue

Feedstock properties and operating condition of the pilot plant test

Conditions

US West Coast

Russian blend

heavy gasoil

Feed sulphur, wt%

1.10

1.44

Feed nitrogen, wt ppm Feed FBP, Simdist, ºC/ºF Fed specific gravity/ºAPI H 2 partial pressure, bar/psi

5,200

1,500

590-600/1,094-1,112

0.92/21

100/1,700

HDS conversion, % HDN conversion, %

94-96 92-95

94-95 70-75

Table 1

2009

2009 2013 2014 2016 2020 2020 2020

nano NiCoMo sulphided slab structures, allowing optimal reactor volume utilisation at all stages of sulphur removal, independent of feedstock nitrogen level. The HDS and HDN activities achieved by TK-594 HyBRIM are compara- ble to pure CoMo and pure NiMo catalyst types, embodying the best performance attributes from each catalyst type, resulting in a higher degree of unit stability while achieving desired product targets and specifications. Optimising DDS and HYD routes Figure 3 shows the results of calculated MoS₂ edge disper - sion via transmission electron microscopy (TEM). S1 and S2 represent the MoS₂ edge dispersion of CoMo BRIM and trimetallic TK-594 HyBRIM catalysts, respectively. Edge dispersion is reflected in slab length (size) and the number of layers (stacking). The HYD route is maximised for short slabs and extended stacking degree of MoS₂, while the DDS route is the most effective when short slabs and low stacking of MoS₂ are present. The TK-594 HyBRIM formu - lation (S2) shows slightly shorter slabs on average and is better described as a catalyst with hybrid properties, mak- ing it efficient for both HYD and DDS routes. It is important to highlight that excessive stacking may lead to a penalty on dispersion and consequent reduced activity. Figure 3 also shows the elemental distribution of the cat- alysts. TK-594 HyBRIM (S2) shows highly dispersed Mo, Co, and Ni metals. Homogeneously uniform dispersion of Ni is especially important for high hydrogenation activity required for deep desulphurisation and elevated aromatic saturation. The CoMo BRIM catalyst (S1) shows equally uniform Mo dispersion. However, Co dispersion is slightly less uniform, with small clusters of Co sulphide present to a small extent. In general, high metal dispersion is an important con- sideration in catalyst selection, as it is not the metal con- tent itself that makes the catalysts highly active but the correct phase distribution in the form of CoNiMoS struc- tures and the accessibility of these metals to promote desulphurisation. Comparative studies Pilot plant trials were conducted at Topsoe R&D facilities in Denmark to assess the application of TK-594 HyBRIM for both European and US West Coast refineries. The tri - als involved utilising relevant feedstock sourced from the

overview of gasoil catalyst development and launch year is shown in Figure 2 . Removal of non-refractive and highly refractive sulphur compounds The effectiveness of a catalyst to remove both non-refrac- tive and highly refractive sulphur compounds throughout the reactor determines overall HDS activity. However, to maximise a catalyst’s performance, it is crucial to optimise its utilisation of pre-hydrogenation (HYD) and direct desul- phurisation (DDS) pathways. The HYD route is well known to be highly inhibited by very complex feed nitrogen com- Figure 2 Evolution of FCC pretreat catalysts portfolio as function to the HDN activity and launched period. pounds, especially basic nitrogen species. Therefore, NiMo catalysts do not become highly active for HDS reactions until the nitrogen concentration reaches an extremely low level. At a lower nitrogen concentration, NiMo catalysts can potentially be less inhibited and more effective at removing the most refractive sulphur compounds. Higher hydrogen partial pressure in the unit creates a kinetically favourable environment and enhances conditions for nitrogen removal while initiating deep desulphurisation more rapidly. Catalyst researchers and providers have extensively researched HYD and DDS mechanism routes, resulting in a deep understanding of the two different reaction pathways and their relationship with metals stack frequency and size. This understanding has led to the trimetallic TK-594 HyBRIM catalyst system for industrial units targeting high HDS levels while maintaining HDN activity for FCC pretreat applications. The system contains highly and homogenously dispersed To maximise a catalyst’s performance, it is crucial to optimise its utilisation of pre-hydrogenation and direct desulphurisation pathways

PTQ Q4 2024