Hydrogen electrolyzer gas-liquid separators must control alkaline electrolyte droplets generated by gas bubbling and foaming. Production rate, liquid level, dynamic load changes, electrolyte chemistry, drainage, pressure drop, and downstream purification requirements all influence separator design.

Mist eliminator support design should consider dry equipment weight, normal liquid holdup, upset or wash loading, fouling deposits, beam deflection, and differential-pressure force. Wet operating weight is process-dependent and should not be represented by one universal multiplier.

Packed tower flooding occurs in the mass-transfer bed, while mist eliminator flooding occurs when liquid accumulates inside the separator faster than it can drain. DP trends, gas and liquid load, drainage condition, and event sequence help distinguish the two.

Mist eliminators remove liquid droplets from gas, while “coalescer” is a broader term that may describe gas-liquid or liquid-liquid equipment. Wire mesh, vane, fiber-bed, cartridge, and liquid-liquid coalescers are not interchangeable even when their names sound similar.

Mist eliminator performance tests can be inaccurate if droplet sampling is nonrepresentative. Probe velocity, sampling location, droplet inertia, condensation, sample-line losses, gas-volume basis, and stable operating conditions all affect the validity of carryover and efficiency measurements.