Horizontal Separator Working Principle

horizontal two phase separator schematic

Horizontal two phase separator schematic

There are three common type of process separator: horizontal separator, vertical separator, or spherical separator. The figure above is an example of horizontal two phase separator basic diagram.

The first step separation occurs at the inlet diverter, on the inlet diverter liquid and vapor will be separated as the fluid enter vessel and hits the inlet diverter that will create sudden change in momentum. The liquid droplet will fall out from the gas stream into the bottom section. Since it will take times to collect the amount of liquid, this section will provide the retention time.

Retention time is needed to vapor the entrained gas in the liquid. If there are slugs in the liquid, this retention time provides a surge volume to handle the slugs. The extracted liquid then flows through an outlet valve which regulated by a level controller.

The gas part will flow over the inlet diverter into the gravity settling section which located above the liquid. The gas may entrain some liquid; this liquid will be separated out by gravity in this gravity settling section and it will fall down to the gas liquid interface.

Before the gas leaves the vessel, it will pass through a coalescing section. The smaller drop which can’t be separated in the gravity settling section will be trapped in the mist extractor. The mist extractor or coalescing section consists of vane element to remove the small droplet.

The pressure inside the vessel is controlled by a pressure controller. If the pressure too high, pressure controller will give a signal to open the pressure control valve so the gas can leave from the vapor space. To maximize the gas liquid interface area, horizontal separator normally operated at half full.

References:
1. Surface Production Operations, Ken Arnold and Maurice Stewart


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