PTQ Q2 2026 Issue

Traditional metrics for catalyst performance, including MAT conversion, surface area measurements, and zeolite crystallinity, provide an incomplete assessment of iron poisoning severity because they do not directly measure the diffusion limitations that govern bottoms cracking per- formance. Against this backdrop, KAI was developed as a specialised test to quantify catalyst accessibility under con- ditions relevant to FCC operations. The KAI test employs a standardised gas oil feed. It meas- ures the catalyst’s ability to crack bulky, high-boiling mole- cules that must diffuse through the pore network to reach active sites deep within the catalyst particle. The test yields a dimensionless index, with higher values indicating bet- ter accessibility. Diffusion limitation refers to the restricted access of hydrocarbons, especially bulky, high-boiling mol- ecules, to the acid sites within the catalyst pores, where desirable cracking reactions occur. High-boiling molecules that struggle to access the pores in the iron-poisoned Upgrader catalyst can effectively diffuse and crack with SaFeGuard. As shown in Figure 1 , commercial E-cat samples typically show KAI values of 5-9 under normal operating conditions. However, during periods of high iron contamination, KAI values can decline (<4), indicating severe accessibility loss and substantially degraded unit performance. The critical threshold of KAI = 4 represents the point where operational problems intensify, including increased slurry production, poor feed conversion efficiency, and rising catalyst con - sumption rates due to accelerated addition rates to main- tain conversion: • KAI >8: Excellent accessibility; minimal diffusion limita- tions; optimal bottoms cracking. • KAI 4-8: Moderate accessibility; some diffusion limita- tions; acceptable performance. • KAI <4: Critical accessibility; severe diffusion limitations; significantly impaired bottoms cracking, elevated slurry, coke and dry gas yields. Commercial trial at FCC unit The second commercial trial was conducted at a North American refinery (Customer Z) operating an FCC unit with the following configuration: • Unit type: FCC unit, 33,000 BPD. • Catalyst inventory: ~140 metric tons. • Feed composition: Blended HGO/VGO/ATB/VTB. • Operating objectives: Maximise VTB processing; min- imise slurry yield; optimise C₄ olefin production; maintain coke selectivity. The trial protocol involved the gradual replacement of E-cat inventory containing 100% Upgrader technology with SaFeGuard catalyst over a period of approximately 30 days. Fresh catalyst additions were made at controlled rates to achieve 50% inventory changeout while maintain- ing stable unit operations. The baseline comparison period used E-cat data from 14 January to 8 April 2025, during which the unit operated exclusively on Upgrader technol- ogy. The SaFeGuard evaluation period spanned 30 June to 15 July 2025 (specific unit design details are withheld to preserve customer confidentiality).

Critical accessibility (KAI <4) Moderate accessibility (KAI <4–8) Excellent accessibility (KAI > 8)

KAI scale

Figure 1 KAI accessibility index ranges

deactivation in a high iron environment. This lab protocol offered key insights into iron tolerance mechanisms and played a crucial role in the development of SaFeGuard technology. For example, the Uprader catalyst deactivated with conventional cyclic deactivation showed a KAI reten- tion of 126%, indicating greater accessibility than the fresh catalyst. In contrast, the new MD protocol with Fe and Ca reduced KAI retention to 26%, more accurately reflecting commercial accessibility loss from iron poisoning. The detailed technical analysis of the second commercial trial of SaFeGuard technology, conducted at a confidential customer site (Customer Z) during June-July 2025, rep- resents a critical validation of the technology under real- world commercial conditions with complex heavy gas oil/ vacuum gas oil/atmospheric tower bottoms/vacuum tower bottoms (HGO/VGO/ATB/VTB) feed mixtures and elevated metal contamination, validated with comprehensive data encompassing E-cat characterisation, laboratory ACE unit testing, commercial performance, and PetroSIM modelling to provide the refining community with a thorough under - standing of this catalyst technology. Fe poisoning mechanisms and KAI Iron enters FCC units through multiple pathways: corro- sion of upstream equipment and piping, contamination in opportunity crudes and renewable feedstocks, and car- ry-over from upstream hydrotreating catalysts. Unlike rare earth metals that integrate into the zeolite framework, or nickel and vanadium that predominantly catalyse undesira- ble dehydrogenation reactions, iron primarily causes physi- cal pore blockage through iron poisoning. It is industrially known that the iron poisoning mechanism proceeds through several steps: u Fe deposits on catalyst particles during cracking cycle. v In the high-temperature regenerator environment, the iron interacts with contaminants, such as calcium, sodium, and silicates, present on the catalyst surface to form low-melting eutectics, creating molten phases. w These liquid phases spread across the catalyst surface, forming a dense glassy layer covering catalyst pores, result- ing in accessibility loss.

PTQ Q2 2026