Floating roof tank can be divided into two types internal floating roof and external floating roof.
Fixed roof and floating roof tanks.
Tanks with external floating roofs are used primarily to contain liquids with high vapor pressures when the vapor emissions from fixed roof tanks would exceed the standards set by the local jurisdiction.
Floating roof tanks are commonly protected against lightning ignition by bonding the floating roof to the seal shoes at no less than 3m 10ft intervals use of insulating sections in the hanging linkages covering sharp points on hangers with insulating materials and installation of electrical bond straps across each pinned hanger joint.
It consists of an open topped cylindrical steel shell equipped with a roof that floats on the surface of the stored liquid.
Domed external floating roof tanks usually result from retrofitting an external floating roof tank with a fixed roof.
An external floating roof tank is a storage tank commonly used to store large quantities of petroleum products such as crude oil or condensate.
Perfect designed internal floating roof storage tank is the best method to control the evaporation loss of the fixed roof tank.
The floating roofs can be either external i e with open top tanks or internal i e inside fixed roof tanks.
Double deck type floating roof 10 figure 1 6.
As with the internal floating roof tanks the function of the fixed roof is not to act as a vapor barrier but to block the wind.
Internal floating roof tank can be used to store gasoline jet fuel and other volatile oil and liquid chemicals like aldehydes alcohols methanol ethanol ketones acetone benzene benzene toluene xylene styrene.
Storage tank capacities and levels 15.
However by reducing emissions the increased costs can be offset or justified on the basis of reduced product loss though evaporation a product savings and less impact to the environment.
Double deck floating roof tank 13 figure 1 8.
A pressure vacuum valve or breather valve is installed which allows the tank to operate at a slight internal pressure or vacuum.
Floating roof tanks are generally about twice as expensive to construct as fixed roof tanks so there is a trade off of risk against cost.
Single deck floating roof tank 12 figure 1 7.
Types of fixed roof tanks 8 figure 1 4.
Single deck pontoon type floating roof 9 figure 1 5.
The roof rises and falls with the liquid level in the tank.
An internal floating roof tank is a floating roof tank fixed an extra fixed roof on the floating roof to prevent floating roof from wind and rain and guarantee the quality of the stored oil.
