70
1
30
AFX
DENALI AFX
AFX Denali AFX
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0.9
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Fe on Ecat Feed Fe
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0.8
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50
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Figure 2 Proprietary mesoporous zeolite in Denali AFX enhances stability
Figure 3 Heavier feeds with higher iron processed during Denali AFX period
To achieve these objectives, Taiyo Oil has developed a sophisticated operational strategy. The refinery team closely monitors changes in FCC feed quality and operational parameters, flexibly adjusting catalyst addition rates based on feed metal content rather than solely on equilibrium catalyst metal content. This approach ensures stable performance and allows the unit to operate at maximum profitability, typically by maximising reactor temperature, catalyst circulation, and optimising the RxCat system. The main operational constraints are regenerator temperature and liquefied petroleum gas (LPG) downstream flow rate, which limit the ability to maximise throughput and propylene yield. Taiyo Oil set out to further enhance profitability by processing even heavier feedstocks. This strategic move introduced new challenges: heavier feeds increase delta coke and regenerator temperature. Higher levels of metals, such as iron, introduced by these
partnered with Ketjen to identify a catalyst solution capable of handling heavier feeds with higher metal content while maximising propylene yields. After extensive feasibility studies and in-house R&D, Denali AFX catalyst was selected. This catalyst features a novel mesoporous zeolite and a metals-tolerant matrix, designed for enhanced stability, improved coke selectivity, and very low hydrogen transfer activity. The catalyst was custom-formulated for Taiyo’s application, with a focus on maximising accessibility and stability under high iron conditions. The impact of the new catalyst is illustrated in Figure 2 , which shows the enhanced stability and surface area of Denali AFX compared to the previous catalyst. Figure 3 highlights the increased iron content in the feed during the trial, while Figure 4 demonstrates the reduction in regenerator temperature achieved, even when processing heavier feeds. These results underscore the importance of tailored catalyst
feeds can negatively impact conversion, bottoms upgrading, selectivity, and catalyst morphology. The company needed to improve delta coke and LPG olefins selectivity to overcome these unit constraints, all while maintaining or improving propylene selectivity. To address these challenges, Taiyo Oil
770
760
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730
AFX Denali AFX
720
710
2
3
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6
Feed Conradson carbon residue (wt%)
Figure 4 Denali AFX reduces regenerator temperature with heavier feeds and higher CCR
Refining India
7
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