What is the difference between LNG storage tanks and ordinary storage tanks?

LNG is a high-pressure liquid stored in cryogenic tanks; it is considered a hazardous chemical, so special attention must be paid during its design. This type of design must be carried out by a qualified entity

Please help determine whether a 5,000 cubic meter vertical storage tank for chemicals, refined oil, and gasoline (with internal floating roof) is a vacuum tank or a pressurized tank. Location of use: Maoming, Guangdong

The last edit to this post was made by yinyayinke on 2020-10-13 at 09:26. Common types of LNG storage tanks in the initial stage include coastal receiving station tanks with large storage capacities of 80,000 cubic meters and 160,000 cubic meters； Storage tanks of liquefaction plants that are smaller in size than those at the receiving station ； Category 3 storage tanks with a capacity of 30 to 150 cubic meters. The storage tanks at the receiving station come in single-enclosure and fully-enclosed types, with a slight positive pressure; those with a capacity of 30 to 150 cubic meters are designed for storage under pressure (the inner tank is made of low-temperature resistant 304 stainless steel, while the outer tank is made of carbon steel).

LNG is generally vacuum-insulated

The main standard referred to in the design of LNG storage tanks is EN 14620-2006. LNG storage tanks are generally of the double-wall full-volume tank structure, and they differ from ordinary petrochemical storage tanks in several aspects: 1. They consist of an inner tank made of 9%Ni low-temperature steel plates, along with an outer tank composed of a reinforced concrete foundation, prestressed concrete walls, and a reinforced concrete roof. The design temperature for LNG storage tanks is -165°C. A rigid foam glass insulation layer is installed beneath the inner tank, while a glass fiber insulation layer is placed on the ceiling. The space between the inner and outer tank walls is filled with mullite sand and elastic blanket insulation layers. The elastic blanket limits the compressive force exerted by the outer insulation layer on the inner tank. The upper parts of the walls and floor are equipped with separate 9%Ni steel linings to form a protection system that safeguards these areas from the effects of low temperatures in case of leaks; this structural arrangement constitutes a Thermal Corner Protection system (TCP).

2. The inner tank bottom plate has two, namely what is referred to as the first layer of bottom and the second layer of bottom. 3. Tank insulation system: The main insulation materials include foam glass, perlite powder, glass fiber blankets, and elastic felt. The basic insulation layer consists of foam glass bricks, which are laid on concrete using asphalt sand. There is a layer of concrete screed between the glass brick and the bottom plate of the tank. The perlite concrete ring beam at the bottom is used to transfer the load of the wall panels to the insulating glass bricks below. Insulation of the tank wall is achieved by using perlite powder to fill the annular space between the inner and outer tanks. On top of the tank, there is a ceiling area that serves as a barrier; this ceiling is sealed to the inner tank using breathable glass cloth. 4. The tanks have a large volume; the tanks being constructed now have a volume of 200,000 cubic meters, while those I was familiar with before were typically 160,000 cubic meters in volume. Therefore, some construction methods differ; for example, the roof of the inner tank is constructed using a pneumatic lifting method, with pressure being used to lift it into place. 5. The material of the inner tank is 9-nickel steel, and the welding processes and methods also vary.

Finished oil tanks are generally atmospheric tanks.

The refined oil is stored in a atmospheric pressure internal floating roof tank, equipped with a vent valve.

LNG is a low-temperature pressure vessel, and liquefied natural gas is considered a hazardous chemical; therefore, the design must be carried out by qualified firms, and the equipment must be purchased from qualified manufacturers.