Troubleshooting in FCC Unit

Presented by Raphael( 肖睿聪 )

Part1 Self-introduction

Hard-working

Confident Optimistic

?

KeyWords

Part2 Introduction of FCC

What is FCC ???• Fluid Catalytic Cracking (FCC) plays a key role in refinery as the primary co

nversion process.The cat cracker holds the key to considerable profit,and successful unit operation determines whether refinery can remain competitive in market.

• The FCC uses microspheroidal catalyst,behaves like a liquid when properly aerated by gas.The main purpose of FCC is to convert high-boiling petroleum fractions---gas oil(portion of crude oil commonly boils from 330°C to 550°C.) to high-value,high-octane gasoline and heating oil.

• The cat cracker must be operated reliably and efficiently. It must also be operated safely and comply with GB Standards and local environmental requirements. A typical FCC circulates tons of catalyst per minute,processes various types of feedstock with hundreds of control loops,any of which can make operation difficult.

Feed PreheatRegenerator—Catalyst Recovery

Gas Plant

Riser—Reactor—Stripper Main Fractionator

The FCC process is very complex. For clarity, the process descriptionhas been broken down into six separate sections:

Treating Facility

Part

3Troubleshooting

Guidelines For Troubleshooting

01

03

Be a good listener Do not draw any conclusions before gathering all applicable facts.

Evaluate causes of problems

Systematically list each cause by brainstorming.

Gather historical background data

Examine similar problems that occurred previously.

Examine goals and constraints to verify the applicability of the present operation

Due to changes in the feedstock, catalyst,etc.

02

04

A successful troubleshooting assignment requires 4 points below:

CATALYST CIRCULATION

Catalyst circulation is like blood circulation to the human body.Without proper catalyst circulation,the unit is dead.

Catalyst circulation is largely influenced by the physical layout of the unit and the fluidization properties of the catalyst.

The first occurs when the maximum circulation has been reached,and the second occurs when the unit is experiencing unstable circulation.

Two Types of Circulation Problems

Excessive pressure drop downstream of the slide valve.

Mechanical problems with the slidel valve.

Three Causes for Insufficient Circulation

Insufficient pressure buildup upstream of the slide valve

Mechanical Ways

Excessive pressure drop

Insufficient pressure

Higher catalyst circulation usually requires opening the regenerated and spent catalyst slide valves.

Lowering the differential pressure across the slide valves.This makes valves open further, until the unit finds a new balance.

Higher circulation increases the pressure drop in the riser and in the reactor cyclones

What we have done to solve this.

Team Work Spirit

Working out Problem with Teamwork Spirit

Hard-working

Confident Optimistic

Comprehensive

KeyWords

Thank You

Raphael