Catalysis 2026 Issue

Historically, when iron levels were higher, this observation was also noted at added iron levels of 1.5 wt%. Furthermore, as seen in Figure 6b , the ABD for in situ catalysts remained stable at this iron level, effectively preventing catalyst fluid - isation issues under conditions of high iron contamination. Product yield and quality effects Often, the type and/or quantity of hydrocarbon constituents in the combined feed to the FCC change due to various factors within the refinery, with an immediate and direct impact on its quality. For example, when normal vacuum gasoil (VGO) or resid feed is replaced partly or fully by an alternate feed such as used cooking oil (UCO), the quality of the combined feed suddenly changes from normal to highly paraffinic (higher KUOP), and its impact is observed on the product yields as well as quality. Conversion and lighter product yields (gasoline, LPG) increase, which may lead to constraints in the downstream main fractionator and/or gas concentration sections. In such a scenario, operational adjustments such as reducing ROT can be easily implemented. However, the paraffinic feed and lower ROT operation also adversely impact gasoline RON. The addition of ZSM-5 additive can help restore gasoline RON, albeit at the cost of reducing gasoline and increasing LPG yield. When VGO or resid feed is replaced partly by alternate feed such as HCGO or DAO, the quality of the combined feed suddenly changes from normal to highly aromatic (lower KUOP), while also increasing other contaminants already discussed earlier. It can also increase the distillation end- point of the FCC feed. All these quality changes can drasti- cally reduce conversion and increase light cycle oil, slurry, and coke yields. Operational adjustments, such as an increase in ROT, might not help much, as this can increase dry gas pro- duction. When such an operation is envisaged for the long term, refiners can consider switching to a higher-activity cat - alyst or a catalyst oriented towards bottoms cracking, which can help recover some of the conversion loss. Summary and conclusions The high degree of flexibility offered by FCC units allows for the processing of extreme feeds to support achieving higher economic margins in a refinery. However, a com - prehensive evaluation of extreme feed impact on combined

Na + V adjusted Delta FACT vs a dded Fe

0 1 3 2 4

-4 -3 -2 -1

Incorporated catalyst FCC 1 In situ catalyst FCC 2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Added Fe (wt%)

ABD vs a dded Fe

0.5 0.5 0.6 0.6 0.7 0.7 0.8 0.9 0.9 0.8

FCC 1

FCC 2 FCC 3 FCC 4 FCC 5

0.2

0.4

0.6

0.8

Added Fe (wt%)

feed quality, as well as a multi-level approach to optimise both process conditions and catalytic system, is needed to maximise the benefits using available unit hardware and operating within its unit constraints. Put simply, processing extreme feeds in FCC units demands a synergistic approach that combines advanced catalyst technology with strategic operational adjustments. These feeds often contain high levels of contaminants, such as Ni, V, Fe, Na, and chlorides, which can degrade catalyst activity, increase coke and dry gas yields, and strain unit operability. To mitigate these effects, refiners must select catalysts with enhanced metals tolerance, optimised pore structure, and robust thermal stability. Technologies such as BBT for nickel passivation and Valor vanadium passivation Figure 6a (above) FACT response vs Fe at three different FCC units. Figure 6b (below) ABD vs Fe response of in situ catalysts at five different FCC units

Catalyst technology strategies to handle major feed contaminants

Contaminant

Effect

Catalyst technology strategy

Dehydrogenation: Increase H₂ and coke

Specialty alumina Boron-Based Technology (BBT) Avoid introduction of Cl into FCC unit (in situ catalyst manufacturing method)

Zeolite destruction Activity reduction

Valor V-Trap

Low Na content catalyst High zeolite content

Dehydrogenation: increase H₂ and coke

Added Fe can block catalyst surface, hindering access to catalyst sites

Catalyst with high porosity and engineered pore architecture

In situ catalyst manufacturing method

Mild dehydrogenation

Table 2

Catalysis 2026