---
title: "FCC regenerator"
description: "The FCC regenerator burns coke deposits off spent FCC catalyst circulating in the unit. Combustion at ~700 °C restores the catalyst's cracking activity for return to the riser-reactor. The hot flue gas produced is routed through cyclone separators (primary and secondary inside the regenerator, then third-stage external) before going to either a CO boiler or a power-recovery expander."
canonical_url: "https://sylio.co/glossary/fcc-regenerator"
last_updated: "2026-06-28T02:29:40.811Z"
---

The **FCC regenerator** burns coke deposits off spent [FCC](/glossary/fluid-catalytic-cracking) catalyst circulating in the unit. Combustion at ~700 °C restores the catalyst's cracking activity for return to the riser-reactor. The hot flue gas produced is routed through cyclone separators (primary and secondary inside the regenerator, then [third-stage](/glossary/third-stage-separator) external) before going to either a CO boiler or a power-recovery expander.

## Fouling concerns

- **Catalyst fines accumulation** in the regenerator cyclone hoppers
- **Refractory-debris accretion** in flue-gas paths after major outages
- **Pluggage** in the third-stage separator's dipleg
- **Dust hopper bridging** below catalyst recovery equipment

## Sonic-horn duty

[Sonic horns](/glossary/sonic-horn) on regenerator-flue-gas-train hoppers and on the third-stage separator catalyst-fines hopper keep catalyst fines flowing reliably back into the unit or to disposal.

## Related terms

- [Fluid catalytic cracking (FCC)](/glossary/fluid-catalytic-cracking)
- [Third-stage separator (TSS)](/glossary/third-stage-separator)
- [Cyclone separator](/glossary/cyclone-separator)