Storage Tanks

Tanks used with respect to petroleum are manufactured keeping in mind the flash point. The tanks normally found within a refinery consist of the floating roof tanks; and the fixed roof tanks. Following is a description with respect to both.

1. The fixed roof tank is best used when the flash point or the temperature at which the vapors will ignite are very high. In this regard fuel oil certainly fits this category. The normal type of roof for this style of storage tank will be shaped as an umbrella, dome or a cone. The cone-shaped roofs and umbrella style roofs are produced in order to keep certain components of the material from causing obstruction or clogging. Heat is produced by the way of coils that generate steam inside of the tanks. The dome shaped roofs are ideal when there are higher levels of pressure with respect to storage in comparison to the atmospheric conditions – an example of this is slop oil.

2. Secondly there are the tanks with floating roofs which are comprised of two types: one being the external roof or FR tanks; and the internal style also known as the IFR tank. The IFR or internal floating roof tanks are used in conjunction with liquid substances such as ethanol and gasoline. Additionally, the IFR internal style floating roof tank is ideal for any liquid with a lower flash point. The design of the IFR tank amounts to a cone-shaped roof which moves in a continual upward and downward motion along with the level of the liquid. The construction employed is able to successfully trap vapors relative to fuels with lower flash points. The fixed roof style storage tank or FR tank in reality does not have a fixed roof at all: rather it is open. The tank in other words has an external floating roof. This tank is idyllic for liquids with flash points considered medium such as crude oil, kerosene and diesel oil.

Tanks used for neutralization purposes within the refinery are known as ISBL tanks. The acronym COT refers to crude oil tanks; PIT is referenced when speaking of intermediate or product tanks. Dependent where the storage tank is found within the confines of the refinery is subject to the accordant acronym.