Storage Tank - For Refineries

For Refineries

Tanks for a particular fluid are chosen according to the flash-point of that substance. Generally in refineries and especially for liquid fuels, there are fixed roof tanks, and floating roof tanks.

1. Fixed roof tanks are meant for liquids with very high flash points, (e.g. fuel oil, water, bitumen etc.) Cone roofs, dome roofs and umbrella roofs are usual. These are insulated to prevent the clogging of certain materials, wherein the heat is provided by steam coils within the tanks. Dome roof tanks are meant for tanks having slightly higher storage pressure than that of atmosphere (e.g. slop oil).
2. Floating roof tanks are broadly divided into external floating roof tanks (usually called as floating roof tanks:FR Tanks) and internal floating roof types(IFR Tanks).

IFR tanks are used for liquids with low flash-points(e.g. ATF, MS. gasoline, ethanol). These tanks are nothing but cone roof tanks with a floating roof inside which travels up and down along with the liquid level. This floating roof traps the vapor from low flash-point fuels. Floating roofs are supported with legs or cables on which they rest. FR tanks do not have a fixed roof (it is open in the top) and has a floating roof only. Medium flash point liquids such as naphtha, kerosene, diesel, crude oil etc. are stored in these tanks.

One of the common types found in mining areas is, open roof type tank, usually to store ore slurries. obviously these are the easiest storage tanks to be constructed.

Other classification which can be made for storage tanks are based upon their location in a refinery:

• COT- crude oil tankages
• PIT- product and intermediate storage tankages
• DISPATCH- dispatch area tankages
• UTILITIES- tanks made in the powerplant area, for storage water etc.
• OSBL tanks- the first 3 types come under out side battery limit tankages
• ISBL tanks- these are usually mini tanks which are found in the production units of a refinery (as neutralisation tanks, water tanks etc.)

As flash-points of fuels go very low the tanks are usually spherical (known as spheres), tom store LPG, hydrogen, hexane, nitrogen, oxygen etc.