Vapor-liquid separator

A Vapor-liquid separator is a vertical vessel into which a liquid and vapor mixture is fed and, in which, the liquid is separated by gravity, falls to the bottom of the vessel, and is withdrawn. The vapor travels upward at a design velocity which minimizes the entrainment of any liquid droplets in the vapor as it exits the top of the vessel.

The feed to a vapor-liquid separator may also be a liquid that is being partially or totally flashed into a vapor and liquid as it enters the separator.

A vapor-liquid separator may also be referred to as a flash drum, knock-out drum, knock-out pot, compressor suction drum or compressor inlet drum.

When used to remove suspended water droplets from streams of air, a vapor-liquid separator is often called  a demister.

Where vapor-liquid separators are used
Vapor-liquid separators are very widely used in a great many indusries and applications, such as:


 * Oil refineries
 * Natural gas processing plants
 * Petrochemical and chemical plants
 * Refrigeration systems
 * Air conditioning
 * Compressor systems for air or other gases
 * Gas pipelines
 * Steam condensate flash drums