The Ketjen Accessibility Index (KAI™) is a proprietary analytical method developed by Ketjen that quantifies catalyst pore accessibility and molecular diffusion characteristics. KAI is meant to show how much of the catalyst surface is actually accessible to hydrocarbon molecules under FCC conditions, rather than just how much surface area exists.
Why Traditional Surface Area Measurements Fall Short
BET surface area has long been a standard metric for evaluating FCC catalysts. It measures the total internal surface available for reactions, but it does not account for whether large hydrocarbon molecules can physically navigate the pore network to reach those sites.
In heavy feed processing, this limitation becomes a real performance constraint. Larger molecules found in vacuum gas oils and resid feeds require accessible pore channels to crack efficiently. A catalyst with high surface area but restricted pore access will not perform as predicted by surface area measurements alone.
KAI addresses this gap by using probe molecules sized to simulate the heavy hydrocarbon molecules that actually flow through an FCC unit. The result is a measurement that correlates directly with commercial cracking performance, particularly for bottoms conversion.
What KAI Measures and How It Is Used
KAI values are derived from a controlled analytical technique that measures how efficiently hydrocarbons molecules diffuse through a catalyst particle. Higher KAI values indicate better pore accessibility and predict stronger performance in applications where large molecule conversion is the objective.
Ketjen uses KAI in four primary ways:
- Catalyst selection. KAI provides refiners with a data-driven basis for matching catalyst accessibility to their specific feedstock characteristics and performance objectives. A refinery processing heavy, contaminated feeds requires different pore architecture than one optimizing for gasoline yield from lighter VGO.
- Performance monitoring. Catalyst accessibility degrades over time as metals deposit and pores become blocked. Tracking KAI through the Equilibrium Catalyst (E-Cat) program allows Ketjen and refinery teams to identify accessibility loss before it significantly impacts yield.
- Competitive analysis. Ketjen applies KAI to evaluate both its own catalyst portfolio and competitive products. This enables objective, like-for-like comparison against market alternatives using the same methodology.
- Catalyst Innovation. Since accessibility is a key metric for catalyst performance where diffusion limitations occur, the KAI measurement is routinely used for research and development projects. It is an essential analytical tool to develop step-out technologies with even higher intrinsic accessibility as well as better accessibility retention. This has been instrumental in developing UPGRADER™ catalyst, RiFT™ technology and most recently SaFeGuard™ technology for step-out performance in highest Fe and Ca applications.
KAI and Commercial Performance: What the Data Shows
Ketjen has established a direct correlation between KAI values and commercial unit performance for bottoms conversion and heavy feed processing. The following catalyst technologies illustrate the practical significance of accessibility in operating units.
UPGRADER is built on an MT-20 matrix architecture specifically engineered for high accessibility. In commercial performance data, UPGRADER has delivered improvements including gasoline yield increases of approximately 2 vol% and slurry reductions of approximately 1.5 vol% compared to conventional catalyst systems. These outcomes are attributed directly to UPGRADER’s accessibility profile, which enables heavier molecules to reach active matrix sites that lower-accessibility catalysts cannot use.
DENALI® is built on a successful combination of boosted mesoporosity on its zeolite technology ZT-600, which delivers higher intrinsic zeolitic stability and retention, which provides a tool for extricating and controlling activity versus hydrogen transfer, AND the matrix technology MT-20 architecture specifically for high accessibility, pre-cracking the heavy molecules. In commercial performance data, DENALI has proven improved yields, especially improved coke selectivity and more selective cracking of larger molecules to assist in bottoms cracking.
SaFeGuard technology is step beyond Ketjen’s standard catalyst technologies. SaFeGuard was developed and designed to deliver superior KAI retention to resist eutectic formation and maintain accessibility under extremely high-metal conditions, especially Fe and Ca, maintaining activity and bottoms upgrading. Commercially, SaFeGuard has proved KAI improvement despite higher added Fe and ATB feed processing. SaFeGuard’s morphology benefits also enables renewable & circular feed co‑processing (up to ~10% without penalty).
Accessibility Across the Ketjen FCC Catalyst Portfolio
Ketjen designs accessibility into its FCC catalyst portfolio across multiple product lines. Starting with the UPGRADER, then the DENALI family, which includes variants such as DENALI AFX™ and DENALI ACTION+, is built to deliver high accessibility alongside superior coke selectivity and an improved stability profile for challenging feedstocks.
The ACTION® catalyst family, including ACTION+, incorporates improved accessibility as a core design feature, enabling better feed flexibility and yield performance across varying operating conditions.
SaFeGuard is a build-on technology that can be applied to ANY Ketjen’s FCC catalyst product lines.
KAI is part of the Equilibrium Catalyst Program, allowing refiners to track accessibility in their circulating inventory over time and respond to contamination events with objective data rather than estimations.
How to Access KAI Testing and Analysis
KAI testing is available through Ketjen’s technical service team. Refiners can request KAI analysis as part of catalyst selection discussions, ongoing E-Cat monitoring, or competitive evaluation work. Results are typically provided alongside Ketjen’s broader catalyst recommendation framework, connecting accessibility data to specific product and operational recommendations.
To learn more about KAI and how it applies to your FCC unit, contact Ketjen’s technical service team or visit ketjen.com.