How many kinds of organic liquid storage tanks

Introduction to Storage Tanks

Storage tanks generally contain organic liquids, non organic liquids and vapors, which application in many industries. Most storage tanks are designed and built according to the American Petroleum Institute API-650 specification. There are many different sizes for these tanks, the range of which is from 2m to 60m or larger in diameter. Above ground storage tanks account for the majority, and most of that is metal structure.

There are basically eight types of tanks used to store liquids: fixed-roof tanks, external floating roof tanks, internal floating roof tanks, domed external floating roof tanks, horizontal tanks, pressure tanks, variable vapor space tanks, LNG (liquefied natural gas) tanks.

Fixed-Roof Tank

At present, fixed-roof tanks adopt the cheapest structure and are generally considered to be the minimum acceptable equipment to store liquids. A typical fixed-roof tank consists of a cylindrical steel shell with a cone- or dome-shaped roof that is permanently affixed to the tank shell. The tanks are usually designed to fully weld, which makes good vapor tight. A Breather Valve (pressure-vacuum Valve), which is normally installed on the top of the fixed-roof tank, allows the tank to operate in a minor internal pressure or vacuum.

External Floating Roof Tank and Internal Floating Roof Tank

There are two forms for the floating roof of external floating roof tank: double floating roof and single floating roof.

When the volume of tank is small, the floating roof is made into a double layer, which is composed of upper and a lower circular steel plates, and a middle partition plate. In order to remove the rain, the top layer of the roof is made into low center and high around. Through drainage, water drain from the bottom of tanks. And its lower roof center is slightly higher than the surrounding in order to collect oil vapor. The floating roof has a layer of air, which can can be very good to play the role of insulation, reducing the impact of atmospheric temperature on the oil. But the steel dosage of double floating roof is large and the structure is complex. When the volume of tank is large, the floating roof is generally a single floating roof under the conditions of sufficient buoyancy in order to save steel. Only the middle part is a single plate, and the other facilities are the same as the double deck floating roof.

The outline structure of the internal floating roof oil tank is roughly the same as that of the external floating roof oil tank. It has a fixed roof, which is favorable for improving the storage condition of oil products. At the same time, the inner floating roof can effectively reduce the wastage of oil.

Horizontal tank

Horizontal oil tank is used to store crude oil, vegetable oil, chemical solvents, water or other oil products. Horizontal tank is composed of an end cover, a horizontal circular tank wall and saddle, which usually used in the production process or gas station. It is generally divided into round, oval, and other irregular shapes.

LNG Storage Tank

Liquefied natural gas storage tank is a special type of tank. It is able to store liquefied natural gas at very low temperature. LNG storage tank has two layer structure: the layer of liquefied natural gas and insulating material layer. The most common tank is full sealed tank.