Applications of HY zeolite
Sourc:The SiteAddtime:2025/12/18 Click:0
Here’s a detailed overview of the applications of HY zeolite, a dealuminated form of Y-type zeolite with enhanced thermal stability and hydrophobicity, making it suitable for diverse industrial processes:
1. Fluid Catalytic Cracking (FCC) in Petroleum Refining
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Role: HY zeolite is a key catalyst in FCC units, which convert heavy hydrocarbon feedstocks (e.g., vacuum gas oil) into lighter products like gasoline, diesel, and propene.
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Advantages:
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High activity: The dealuminated framework (lower Si/Al ratio) provides strong Brønsted acidity, improving cracking efficiency.
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Thermal stability: Withstands temperatures up to 700–800°C in FCC regenerators.
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Coke resistance: Reduced coke formation compared to conventional Y zeolites, extending catalyst lifespan.
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Example: HY catalysts achieve >70 wt% conversion of heavy oil to gasoline, with a selectivity of >60% for high-octane components.
2. Hydrocracking of Heavy Hydrocarbons
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Role: HY zeolite is used in hydrocracking to break down heavy residues (e.g., vacuum residue) into middle distillates (jet fuel, diesel) under high pressure (10–20 MPa) and temperature (350–450°C).
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Advantages:
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Acid site balance: Moderate acidity prevents excessive cracking to light gases, favoring liquid product yield.
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Hydrogenation activity: When combined with metal catalysts (e.g., Ni-Mo or Co-Mo), HY enhances desulfurization and denitrogenation.
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Example: HY-based catalysts achieve >85% conversion of vacuum residue to diesel with <10 ppm sulfur content.
3. Isomerization of Light Paraffins
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Role: HY zeolite catalyzes the isomerization of linear alkanes (e.g., n-butane to isobutane) to produce high-octane gasoline blending components.
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Advantages:
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Shape-selective catalysis: The 12-membered ring pores (0.74 nm) accommodate linear alkanes while restricting branched isomers, favoring equilibrium shifts.
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Low coke formation: Dealuminated HY resists coking, maintaining activity over long cycles.
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Example: HY catalysts achieve >90% conversion of n-butane to isobutane at 250–300°C and 1–3 MPa.
4. Alkylation of Aromatics
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Role: HY zeolite catalyzes the alkylation of benzene with ethylene or propylene to produce ethylbenzene or cumene (isopropylbenzene), key intermediates for styrene and phenol production.
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Advantages:
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High selectivity: The pore structure restricts byproduct formation (e.g., polyalkylated aromatics).
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Regenerability: HY can be regenerated via calcination to restore activity after deactivation by coke.
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Example: HY catalysts achieve >95% selectivity for cumene in benzene-propylene alkylation at 150–200°C and 2–4 MPa.
