PetroStreet

How could wrong dose of corrosion inhibitor play a role in foaming inside the separator, what are the consequences, and how to best avoid such situations?

Most of the killing happens when the dose of CI is too high.
Excessive surfactant accumulates in liquid phase, gas bubbles get coated with inhibitor film, bubble coalescence gets prevented, and eventually foam gets stable, and persistent.
It can however happen with low dose also but this may not be the common failure type.
Compatibility issues of CI with the service can be a cause as well with poor injection as a contributor too.
Consequences are all the same with liquid carryover to gas systems, to export products however potential mechanical damages can occur as well including compressor damage, erosion-corrosion of downstream piping, etc.

On the avoidance, you must monitor the dose (should not be anybody's guess).
Base that on water cut, flow rate, corrosivity, and temperature.
That has to be like ppm in water phase not just like L/hr.
The changes in the dose are required to be made in small increments, and observe separator behaviour over hours, not minutes. This is important.
Compatibility testing is critical so before field use, the bottle test are recommended with CI, demulsifier, antifoam, and actual crude. This is even more important.
Obviously, monitoring would play a vital role, control system safeguards, flow changes, CI rate vs separator level instability.

Quite clear that is.
Thanks all.