naRTC 2026
Advantages of high-throughput comparative catalyst testing for naphtha reforming changeouts
Wilbert L. Vrijburg AVANTIUM
activity, selectivity, and stability. Two hor- izontal dashed lines indicate target RON levels (RON1 and RON2). Vertical dashed lines show the corresponding tempera- tures required for each catalyst to achieve these RON targets. For both RON1 and RON2, Catalyst A required a significantly lower temperature to obtain the target RON vs Catalyst B. Lower required tem- peratures for a given RON indicate higher catalyst activity, while slope analysis reveals sensitivity to temperature changes and potential selectivity trade-offs. The octane sweep provides the start- ing temperature required for the iso-RON tests. To best mimic SOR performance, these tests should achieve the target RON temperature without an induction period. Figure 2 shows how C5+ yield evolves with catalyst time on stream (TOS) for the same two CCR reforming catalysts, as shown in the octane sweep. Both curves exhibit a typical trend: yield increases initially, reaches a maximum, and then declines as TOS progresses due to catalyst deac- tivation and coke formation. Two coke val- ues (low vs high) are indicated on each curve. From the iso-RON run ( Figure 2 ), we observe that despite requiring a higher T at target RON conditions, Catalyst B exhibits both a higher C5+ yield as well as a slower coke build-up than Catalyst A. However, the C5+ yield is more sensitive to coke con- tent for Catalyst B than for Catalyst A. The catalyst selectivity evolution at constant RON with increasing TOS and coke con- tent highlights the value of comparing CCR catalysts at the target RON and within tol- erable coke limits. This study highlights the trade-off between initial activity (octane sweep) and long-term stability (time on stream). This combined analysis is critical for CCR cat- alyst selection, as both SOR performance and coke management over time deter- mine commercial viability. Avantium provides the following stud- ies for naphtha reforming comparative catalysts: • CCR reforming : Octane sweep + iso- RON with coke impact study. • SR reforming : Octane sweep + iso-RON and accelerated deactivation. References 1 Tiago Vilela and Nattapong Pongboot, PTQ Q2 2025 , 51-53. 2 Tiago Vilela, Nicolas Popoff, and Mark Moser, PTQ Catalysis 2021 , 39-42.
Each catalyst changeout gives a key opportunity for a refinery to steer the per- formance and profitability of a particular unit. Given the substantial costs asso- ciated with catalyst procurement (typi- cally in the range of $10-20 million)¹ and the continuously evolving fuel standards, emission policies, and feedstock com- position, reliably selecting the optimal catalyst for a refinery unit remains a mul- tifaceted challenge. Over the past dec- ade, Avantium’s Refinery Catalyst Testing (RCT) service has supported refineries in derisking the catalyst selection process through efficient and reliable comparative catalyst testing. In the Netherlands, the expression of ‘measuring is knowing’ (Dutch: ‘meten is weten’) is part of the vernacular of com- panies committed to making data-driven decisions. Within the niche context of refinery catalyst changeouts, using objec- tively measured data – such as perfor- mance, selectivity, and stability – that compares multiple catalyst options (includ- ing multiple catalyst vendors and systems per vendor) and employs the refinery’s own feed will provide the best insights into which catalyst is most suitable for the next changeout. This article highlights how Avantium’s RCT services have recently supported refineries in navigating the mul- tiple catalyst proposals for their continu- ous catalyst regeneration (CCR) reforming catalyst changeouts. Challenge: Committing to a long-term catalyst choice The key objective in the catalytic reforming process is to convert naph- tha fractions into high-octane aromatic hydrocarbons as selectively as possible. In addition, the reforming unit is the main hydrogen producer (for use within or out- side of the refinery) and provides chemical feedstock for downstream petrochemical processes. Earlier works have shown that an increase of 0.5 wt% in C5+ yields can have an annual gain of $1 million. For hydrogen yields, and in particular for those refin- eries that are hydrogen constrained, a 10% increase in hydrogen production can lead to an annual value increase of around $10 million.² Despite reforming catalyst changeouts being less frequent than those of other units within the refin- ery, independent catalyst testing is a vital step to ensuring up to a decade of maxi- mum profitability and value from a reform- ing unit.
A B
Catalysts
A B
RON 1
Low Coke value
High Coke value
Low Coke value
RON1 ΔT
B
RON2
High Coke value
A
RON2 ΔT
RON1, CatB T
RON1, CatA T
Time on stream (hr)
RON2, CatA T
RON2, CatB T
Reactor temperature (˚C)
Figure 2 C5+ yield vs time on stream for two different catalysts (aromatics and hydrogen yields also measured)
Approach: High-throughput testing with Avantium’s reforming testing solutions Avantium employs a 16-reactor high- throughput catalyst testing setup that is optimised for naphtha reforming catalyst testing. Rather than simply comparing a sin- gle catalyst system per vendor, its compara- tive test designs for both semi-regenerative (SR) and CCR typically include multiple pro- posed solutions from each catalyst vendor. Each reactor has individual temperature control, along with harmonised feed and pressure controllers, to ensure direct com- parisons between catalysts. Given the varying product yield desires from different refineries, Avantium’s sys- tems rapidly measure and monitor C5+ yields, aromatic yields, and hydrogen pro- duction using online gas chromatography (GC). An automated feedback loop between the GC product analysis and reactor tem- perature enables operation at a constant Research Octane Number (RON) (iso-RON), with temperature adjusted per reactor (and therefore per catalyst) to maintain the target RON. For naphtha reforming projects, Avant- ium’s dedicated testing systems are compatible with all naphtha reforming pro- cesses, requiring as little as 20 litres of refinery naphtha feed. Its methodology is independently validated by leading global catalyst vendors, including UOP and Axens. A critical step, particularly for CCR cata- lyst benchmarking, is an octane sweep in which each catalyst system is exposed to a stepwise temperature increase and RON measurement. This results in a tempera- ture vs RON profile that is vital to ensuring that any iso-RON measurement is initiated at start-of-run (SOR) conditions with mini- mum catalyst deactivation. Particularly for Figure 1 Octane sweep of catalysts A and B (conditions in the range of RON 85-110, temperature 450-520°C, ΔT RON1 > ΔT RON2 )
DID YOU KNOW? For naphtha
CCR catalyst comparisons in fixed beds, the rapid catalyst deactivation (along- side the evolving catalyst selectivity at increasing coke content) necessitates an octane sweep prior to any iso-RON study. The importance of performing both tests for CCR catalyst comparison based on a recent project with a European refinery is highlighted below. CCR catalyst selection: power of combining Octane Sweep with Iso-RON measurements Figure 1 shows an octane sweep for two CCR reforming catalysts, labelled A (blue) and B (red), within a test programme for a refinery customer. Each curve repre- sents the octane sweep profile for a cata- lyst, with experimental data points plotted along the fitted trend lines. By running multiple temperature setpoints per reac- tor, the sweep captures catalyst response to severity changes, offering insights into reforming projects, avantium’s dedicated testing systems are compatible with all naphtha reforming processes, requiring as little as 20L of refinery naphtha feed
Contact: wilbert.vrijburg@avantium.com
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