Common design problems of sump tanks

Journal Article · Tue Feb 01 04:00:00 EST 1994 · JPT, Journal of Petroleum Technology; (United States)

OSTI ID:5452260

Thro, M E

When gravity settling is used for water treating, the buoyancy of oil droplets makes them rise at a velocity proportional to the difference between the specific gravities of water and oil (Stokes' law). If the flow rate in a vertical vessel or skim pile is such that the average water velocity from the water inlet to the vessel outlet is greater than the droplet velocity as it rises owing to buoyancy, the droplet will be carried out with the water. The maximum flow rate for a vertical of horizontal sump is proportional to the difference in specific gravities. If a vessel is sized for produced water and oil but also is being used for rain water from deck runoff, the allowable flow rates for the two cases are different because of differences in the specific gravities of water and oil. Rain water normally has a lower specific gravity than produced water, and oil washed off the deck into the sump by rain is weathered oil with a specific gravity greater than that of the fresh oil. Improper sizing of sump tanks can result in water treating and sheen problems because of excessive flow or incorrect weir placement. When sizing a sump, it is important to consider the actual fluids involved. The difference in specific gravities between process water and light oil or condensate can be significantly higher than that for rain water and weathered oil. This difference in specific gravities has a significant impact on sump size and weir configuration, and must be taken into account for design purposes.

• OSTI ID: 5452260
• Journal Information: JPT, Journal of Petroleum Technology; (United States), Journal Name: JPT, Journal of Petroleum Technology; (United States) Vol. 46:2; ISSN 0149-2136; ISSN JPTJAM
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020800* -- Petroleum-- Waste Management
CONTAINERS
DENSITY
DESIGN
FLOW RATE
HYDROGEN COMPOUNDS
LIQUID WASTES
OFFSHORE PLATFORMS
OXYGEN COMPOUNDS
PETROLEUM PRODUCTS
PHYSICAL PROPERTIES
RAIN WATER
TANKS
WASTE WATER
WASTES
WATER
WATER TREATMENT PLANTS