3. Direct condensation of pure steam

Many processes involve direct contact between the steam to be condensed and a heat transfer fluid. Because there is no wall separating the two fluids, direct-contact exchangers do not pose corrosion or fouling problems, but certain operating regimes of these exchangers can lead to violent pressure fluctuations in the system.

The different types of flow for direct condensation are :

• stratified flow of steam and liquid ;

• condensation on liquid jets or film;

• injection of liquid droplets into the steam ;

• injection of vapor bubbles into a liquid.

Like film condensation, direct condensation is governed by the interaction of vapor and liquid flows. There is no general correlation for all...