Page 165 - Fluid Catalytic Cracking Handbook

CHAPTER 5

Unit Monitoring

and Control

The only proper way to monitor the performance of a cat cracker
is by periodic material and heat balance surveys on the unit. By
carrying out these tests frequently, one can collect, trend, and evaluate
the unit operating data. Additionally, meaningful technical service to
optimize the unit operation should be based on regular test runs.
Understanding the operation of a cat cracker also requires in-depth
knowledge of the unit's heat balance. Any changes to feedstock quality,
operating conditions, catalyst, or mechanical configuration will impact
the heat balance. Heat balance is an important tool in predicting and
evaluating the changes that will affect the quantity and the quality of
FCC products.
Finally, before the unit can produce one barrel of product, it must
circulate catalyst smoothly. One must be familiar with the dynamics
of pressure balance and key process controls.
The main topics discussed in this chapter are:

• Material Balance
• Heat Balance
• Pressure Balance
• Process Control Instrumentation

In the material and heat balance sections, the discussions include:

• Two methods for performing test runs
• Some practical steps for carrying out a successful test run
• A step-by-step method for performing a material and heat balance
survey
• An actual case study

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