FLOATING ROOF TANK
What is Floating Roof?
A Floating Roof as its name implies, actually floats on the surface of the liquid in the tank. As the liquid level changes the roof is designed to move up and down with the liquid level - i.e. Filling, Emptying, Expansion and Contraction due to temperature changes. This type of tank roof minimizes the vapor space between it and the liquid surface. Since there is no large vapor space for the liquid to evaporate into, vapor losses are also minimized.
In its simplest form, the floating roof is merely a large, disc, slightly smaller in diameter than the tank shell. It is fitted with a system of flexible 'shoes' to close the space between the edge of the roof and the tank shell in order to minimize vapor loss.
In modern usage, there are two main designs of floating roof:
The 'Pontoon' roof
The 'Double-Deck' roof
Floating roof tank which is in use to store hydrocarbons having a greater tendency of vapour generation on exposure to high temperature i.e. having higher vapour pressure. The floating roof helps in vapour suppression. They can be constructed inside in the tanks with fixed roofs.
This consists of a series of pontoons around the outer edge of a central plate. This construction increases the floating stability. The roof is also sloped towards the center to allow rain water to flow into a water drainage system.
This is a development which employs two separate decks of steel plate over the entire tank area. The space between the upper and lower plates is divided into compartments. The double-deck roof therefore, has much lower evaporation losses than any other type of floating roof.
EXTERNAL FLOATING ROOF TANK
An external floating roof tank is a storage tank commonly used to store large quantities of petroleum products such as crude oil or condensate. It comprises an open- topped cylindrical steel shell equipped with a roof that floats on the surface of the stored liquid.
Internal floating roof of Aluminium pantoon
These tanks have internal floating roof made of light weight aluminium pantoon and are easy to install and operate and provide excellent solution for prevention of vapour losses from liquid evaporation.
The tanks are made in various capacities
Volume: Ranging from 200m3 to 15 million liters and above
Diameter: Ranging from 5 mtrs to 60 meters and up
Height: Ranging from 5 mtrs to 20 meters and up
Design code: API 650 and others
Past Projects for Floating Roof Tank:
• Gasoline storage tank - 3 x 7000 m3
• Jet fuel storage tanks - 5 x 3 million gallons
• Petrol storage tank - 5 x 8200 cum.
• Kerosene storage tank - 4 x 2 million gallons
• Crude oil storage tank - 3 x 10500 m3
• Ethanol storage tank - 6 x 7500 cum.
• Molasses storage tank - 3 x 3300 cum.