64 68 66 70 72 76 74 78
0 2000 1000 3000 4000 5000 6000 7000 8000 9000
Global
Americas
Asia
EMEA
Global
Americas
Asia
EMEA
Figure 3 Global fluidised catalyst activity trend
Figure 4 FCC Feed contaminants: nickel and vanadium
consistent over the entire 21-year history, with the most significant shifts happening at the same time REO drops are observed, i.e., during the REO crisis (2011) and since 2017. The higher catalyst surface area partially accommo - dates the loss in activity from lower REO. Higher surface area is achieved through several ways: higher fresh catalyst surface area, higher catalyst addition rate, and/or improved surface area retention. An equally compelling trend emerging since our last analysis in 2015 is the zeolite-to-matrix ratio (Z/M) signifi - cantly decreased in all regions, favouring lower Z/M values. For such a drastic change, this requires not just one unit but entire regions to change their catalyst appetite. The Americas has seen the steepest curve, meaning its adoption of lower (lowest) Z/M ratio is the most drastic. This is likely due to two factors: matrix activity helps with LPG olefins generation (especially butylenes), and active matrix is very effective at bottoms cracking. The fact that bottoms is typi - cally one of the least valued products from a refinery drives most refineries to minimise this product from the FCC unit. This change is also in favour of more LCO or diesel produc - tion, which currently is experiencing record-high prices. The Ecat activity is a function of both rare earth and TSA (among other variables) and is shown in Figure 3 . Ecat activ - ity and all Ecat yields are measured using an ACE 2 technology laboratory unit. This unit mimics a commercial FCC unit and is run at constant conditions, so any changes are due solely to the catalyst. Great fluctuations have been observed during the two-decade Ecat activity history. Most recently, a global trend favouring lower activity is observed, particularly during the Covid-19 pandemic (2020 and 2021) and has started to rebound during the economic recovery period (2022). Not only was total demand for refined products lower during the pandemic, but there was a shift in product mix. With fewer passenger vehicles on the road, demand for gasoline was down, while diesel (needed to transport goods) and chemical precursors (such as propylene for manufacturing medical face masks and other polyolefin plastics as single-use material demand increased for sani - tary reasons) were still needed. The low catalyst activity in 2020 and 2021 favours production of light cycle oil (LCO), a diesel precursor. This graph also shows that outside the Americas region, other regions run lower activity overall due to the higher demand for diesel over gasoline. Additionally,
the Americas region processes, on average, lower con - taminant feed (see Figure 4 ), which leads to higher activity needed to meet heat balance constraints. Figure 4 shows common Ecat contaminant metals, a result of contaminants coming in with FCC feed. The two most prevalent contaminant metals include nickel and vanadium. Both have been on the downturn in recent years after reaching a peak in 2016. The global average today hovers around 3,000 ppm Ni+V. This suggests that global access to lower contaminant metal feeds has increased due to cleaner crudes (such as tight oils) and/or increased pre - treating hydroprocessing capacity. Also noticeable is the lower 10% shaded area, which shows that the very low metals units have even lower metals today, likely due to more severe hydrotreating to meet increasingly stringent gasoline sulphur specifications. Catalyst selectivity Catalyst selectivities, which are impacted by contami - nant metals, will be reviewed in the following discussion. Hydrogen yield is a function of the metals levels, which catalyse dehydrogenation reactions to produce hydrogen and coke. The hydrogen yield follows the metals (Ni+V) trend, as shown in Figure 5 , peaking in 2016 and since has declined. Lower hydrogen levels are also influenced by catalyst metals passivation technologies. Hydrogen yields decrease as catalyst suppliers continue to innovate new and improved metals-tolerant catalysts. Coke is a product with zero value but is also required to maintain the heat balance in the FCC unit and is impacted by contaminant levels coming from the FCC feed. Coke in the ACE reactor increases with higher activity and higher metals. Over the past 10 years, activity and metals were steady enough not to increase coke selectivity. We origi - nally expected to see coke decline due to improvements in catalyst coke selectivity and metals tolerance technol - ogy; however, we found that coke selectivity has stayed relatively consistent. It is believed that the improved cata - lyst coke selectivity is offset by units needing higher coke selectivity due to processing cleaner feeds, such as tight oils or more severely hydrotreated feeds to meet gasoline sulphur regulations. We have seen more hydrotreating in recent years, especially in the Americas, due to sulphur regulations.
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Catalysis 2023
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