What is the purpose of using floating roofs in the tanks that stores oils like petroleum?

Question

What is the purpose of using floating roofs in the tanks that stores oils like petroleum?

Answer 1

It allows the release of pressure.

Answer 2

petroleum forms vapor very easily and at normal outside temperature may produce enough vapor (and pressure) to blow up the container.. so by having floating roofs (that go up as pressure increases and come down as it decreases) we can easily prevent that from happening by installing sensors which help in maintaining a "safe" level in the storage tank...

Answer 3

to decrease evaporation , by decreasing the amount of air in contact with the oil

Answer 4

For Safety reasons.

In a conventional tank, when liquid is being pumped out, the falling liquid level can cause a vacuum within the tank with the possiblity of a tank collapse (Implosion). These tanks generally have an inert gas injection (usually Nitrogen) and a control system to maintain a positive pressure. They also have a safety relief on the top to take care of pressure build up when filling.

With a floating roof tank, (Pontoon and Double-deck types), pressure is not involved in its operation. No pressure build up takes place as an automatically controlled vent releases excess pressure.

The roof literally floats on the surface of the liquid and moves up and down with the liquid level. Legs are fitted below the roof to hold it off the tank bottom in a low level situation.

Special seals are used between the tank roof and the tank sides to prevent ingress of air on falling level and venting of liquid with a rising level.

One danger of floating roofs is that the space above the roof and the top of the tank can become filled with heavy gases. An operator going down onto the roof into this space to take a sample or to dip the tank could be overcome by the gases. Every care must be taken in this case. The operator will carry a gas detector for checking purposes while descending onto the roof and will have a companion carrying breathing apparatus at the top of the access ladder in case of need.

No need for thumbs down. I've worked with storage and tankage and other aspects of oil and gas for all of my working life. Please give it up, you can't win.

Answer 5

Because a floating roof remains directly above the surface of the liquid, the amount of vapor that can collect above it is decreased. This is a safety precaution, as many fuels' vapors are extremely flammable or accumulate in large quantities and can escape into the atmosphere.