How to Retrofit a Packed Tower with Persistent Foaming
Foaming can dramatically change tower hydraulics.
A process that appears acceptable in clean hydraulic calculations may experience high pressure drop, entrainment, and unstable operation when foam develops.
Confirm That Foaming Is the Cause
Foaming may produce:
- unstable differential pressure;
- excessive liquid carryover;
- apparent early flooding;
- fluctuating liquid levels.
Identify Why Foam Forms
Potential drivers include:
- surface-active contaminants;
- reaction products;
- biological material;
- excessive gas velocity;
- process chemistry.
Packing Selection May Need to Change
More open packing can sometimes tolerate foaming better than dense high-surface-area designs.
Improve Disengagement Space
Additional free space above the bed can allow foam and droplets to collapse before reaching the demister.
Evaluate Liquid Distribution
Localized overloading can intensify foam generation.
Review the Demister Carefully
A demister can remove droplets, but it cannot compensate indefinitely for large volumes of foam reaching the tower top.
Consider Process-Side Controls
Antifoam or chemistry changes may be relevant, depending on the process.
Mechanical retrofit alone may not solve chemically generated foam.