Personal tools
You are here: Home SIMULATIONS Simulations: Refineries FCCU


FCCU Tutorial


FCCU Simulation


Envision Systems FCCU Tutorial
Copyright © 2009 by EnVision Systems Inc. All rights reserved worldwide.

FCCU (Fluidized Catalytic Cracker Unit) Tutorial

The interactive FCCU tutorial provides an overview, fundamental principles, control principles and operating principles for a fluidized catalytic cracker unit, using voice, video, animation and graphics. The topics covered are:


  • Introduction
  • Importance of FCC Unit
  • Process Overview

FCC Unit Components   

  • Feed Preheat System
  • Reactor System    
  • Regenerator System
  • Flue Gas System
  • Variation of Reactor and Regenerator System    
  • Fractionation System

Principles of FCC Unit

  • Cracking Reactions    
  • Fluidization Principles
  • Catalyst Circulation
  • Energy Balance in Reactor and Regenerator

Key Controlled and Operating Variables

  • Introduction    
  • Reactor Temperature
  • Catalyst to Oil Ratio
  • Reactor Pressure    
  • Catalyst Bed Level
  • Regenerator Temperature
  • Delta Coke
  • Complete and Partial Combustion Modes
  • Afterburning and CO Promoter
  • Air Flow
  • Air Distribution
  • Slide Valve
  • Riser Lift-Steam and Feed Dispersion-Steam
  • Stripping Steam
  • Feed Properties
  • Catalyst Activity and Selectivity
  • Catalyst Loss and Addition

Startup Operation

  • Introduction    
  • Pre-Startup Check
  • Regenerator Main Air-Blower Startup
  • Regenerator – Reactor Warm Up
  • Regenerator Catalyst Addition
  • Regenerator Torch Oil Firing
  • Regenerator – Reactor Catalyst Circulation
  • Main Fractionator Bottom Fill Up
  • Main Fractionator and Feed Heat Up
  • Riser Feed Introduction
  • Reactor and Regenerator Stabilization
  • Fractionator Overhead Section Startup
  • Fractionator Bottom Section Startup
  • Fractionator Light Cycle Oil (LCO) Section Startup
  • Fractionator Heavy Cycle Oil (HCO) Section Startup
  • Load Increase to Design Condition    


  • Introduction
  • High Light Gas Yield
  • Low Gasoline Yield
  • Low Catalyst Activity and Selectivity
  • Flow Reversal
  • High Regenerator Temperature
  • Severe Afterburning
  • Insufficient Combustion Air
  • Loss of Catalyst
Envision Systems FCCU Simulation
Copyright © 2009 by EnVision Systems Inc. All rights reserved worldwide.

FCCU (Fluidized Catalytic Cracker Unit) Simulation

The FCCU simulation is a rigorous and high-fidelity mathematical process model that provides a realistic dynamic response for a fluidized catalytic cracker unit.

Process Overview:

Fluidized catalytic cracker (FCC) converts gas oils and heavy stocks into high-octane gasoline, light fuel oils and light gases rich in olefins. The following products are typically obtained from a fluidized catalytic cracking unit: wet gas, unstabilized gasoline, light cycle oil (LCO), heavy cycle oil (HCO) and slurry oil (SLO).

Major Sections:

  • Reactor Section
  • Regenerator Section
  • Main Fractionator Section
  • Wet Gas Compressor Section

The FCC simulator is available in various configurations, such as regenerator with partial or complete combustion, with/without catalyst cooler.

Major Operations for Trainee Practice:

  • Startup and Shutdown Operations
  • Normal Operations
  • Emergency Shutdown Operations
  • Troubleshooting Equipment, Instrument and Control Valve Malfunctions
  • Malfunction Recovery Actions


Simulation Features:

  • Effect on Reaction Yield and Coke Yield
    • Reactor Temperature
    • Catalyst to Oil Ratio
    • Lifting and Dispersion Steam
  • Hydrocarbon Carry-Over in Spent Catalyst
  • Afterburning
  • Flow Reversal
  • Coke Snow-Balling
  • Effect of CO Promoter on Regenerator
  • Interlock/Safeguard System


  • Detailed Calculation of the Products Properties
    • Complete ASTM Analysis of All Products
    • Reid Vapor Pressure and Flash Point of Gasoline
    • Pour Point of LCO and HCO
    • Viscosity of SLO
  • Plant Alert and Monitor
  • Equipment Details
Document Actions
Top of page