Adequate vessel diameter and height or length to allow most of the liquid to separate from the gas so that the mist extractor will not be flooded. Any solids gas oil separation plant pdf as sand will also settle in the bottom of the separator. 10 or 12 feet in diameter and 15 to 25 feet S to S.
4 to 5 feet S to S up to 15 to 16 feet in diameter and 60 to 70 feet S to S. Spherical separators are usually available in 24 or 30 inch up to 66 to 72 inch in diameter. Both types of units can be used for two-phase and three-phase service. A monotube horizontal oil and gas separator is usually preferred over a dual-tube unit.
It is also easier to clean than the dualtube unit. The monotube design normally has a lower silhouette than the dual-tube unit, and it is easier to stack them for multiple-stage separation on offshore platforms where space is limited. The three configurations of separators are available for two-phase operation and three-phase operation. The oil-water separation section is held for a retention time that is provided by laboratory test data, pilot plant operating procedure, or operating experience. In the case where the retention time is not available, the recommended retention time for three-phase separator in API 12J is used.