Hydrogen and clean fuel projects are new, but the unit operations inside them are not. Purification is pressure-swing adsorption; drying is molecular sieve; synthesis loops need reactor internals that distribute flow evenly across a catalyst bed. All of it is separation and mass transfer engineering.

What is different is the duty cycle. PSA vessels switch pressure many times a day, and electrolysis-fed plant may follow a variable renewable supply — so internals see far more cycling than a conventional continuous unit.