Best Zeolite for FCC

There is no single best FCC zeolite — the optimal choice depends on the refinery’s product slate, feedstock, and regenerator severity. An FCC catalyst is a composite, not a single zeolite. Most commercial units use USY as the primary cracking component combined with ZSM-5 as a propylene and octane additive.

Quick Decision Guide

How to Choose

Start with USY. For any FCC unit cracking gas oil, USY is the base cracking component. Select your USY grade by unit cell size (UCS): lower UCS for gasoline selectivity and propylene maximisation; higher UCS for maximum conversion. Add rare-earth exchange (RE-USY) if gasoline is the priority product.

Add ZSM-5 if you need propylene or octane. ZSM-5 is an additive, not a replacement for USY. Start at 2-5 wt% of catalyst inventory for moderate propylene enhancement; increase to 5-10 wt% for maximum propylene mode. ZSM-5 does not replace the base cracking function of USY.

Use HY for matrix acidity. In catalyst formulations where the matrix needs high cracking activity and the matrix experiences milder conditions than the USY component, HY provides additional acid sites. This dual-zeolite approach is well-established in FCC catalyst manufacturing.

Start from Y zeolite if you formulate your own catalyst. Na-Y is the precursor for both HY and USY. If your organisation controls ion exchange and dealumination in-house, start from high-crystallinity Na-Y with your specified SiO₂/Al₂O₃ ratio.

For detailed comparisons, see HY vs USY and the FCC solution hub. When requesting a sample, tell us your target product slate (gasoline vs propylene), feedstock type, and regenerator conditions.