Classification
Due to the different storage media, the forms of storage tanks are also diverse.
Classified by location: can be divided into aboveground storage tanks, underground storage tanks, semi-underground storage tanks, offshore storage tanks, subsea storage tanks, etc.
Classified by oil: it can be divided into crude oil storage tanks, fuel storage tanks, lubricating oil tanks, edible oil tanks, fire water tanks, etc.
Classified by purpose: can be divided into production tanks, storage tanks, etc.
Classified by form: can be divided into vertical storage tanks, horizontal storage tanks, etc.
Classified by structure: can be divided into fixed roof storage tanks, floating roof storage tanks, spherical storage tanks, etc.
Classified by size: Large storage tanks above 50m3, mostly vertical storage tanks; small storage tanks below 50m3, mostly horizontal storage tanks.
According to the material of the storage tank: the materials required for the storage tank project are divided into tank body materials and auxiliary facility materials. Tank materials can be divided into low-strength steel and high-strength steel according to tensile yield strength or tensile standard strength. High-strength steel is mostly used for storage tanks above 5000m3; ancillary facilities (including wind-resistant ring beams, locks, ladders, guardrails, etc.) Common carbon structural steel with lower strength is used, and the other parts and accessories are made of other materials according to different uses. The domestic steels commonly used in the manufacture of tank bodies are 20, 20R, 16Mn, 16MnR, and Q235 series.
structure
The most widely used in my country and the most mature production and installation technology are vault storage tanks, floating roof storage tanks and horizontal storage tanks.
Vaulted
Vault storage tank refers to a steel container with a spherical crown and a cylindrical body. Vault storage tanks are simple to manufacture and low in cost, so they are most widely used in many industries at home and abroad. The most commonly used volume is 1000-10,000m 3, and the maximum volume of domestic vault storage tanks has reached 30,000m 3.
Tank bottom: The tank bottom is assembled by steel plates, the steel plate in the middle of the tank bottom is a medium-width plate, and the surrounding steel plates are edge plates. The edge board can be a strip-shaped board or a bow-shaped board. Under normal circumstances, when the inner diameter of the storage tank is less than 16.5m, the strip edge plate should be adopted, and when the inner diameter of the storage tank is ≥ 16.5m, the arched edge plate should be adopted.
Tank wall: The tank wall is formed by butt welding of multiple rings of steel plates, which are divided into sleeve type and linear type.
The circumferential welding seam of the sleeve type tank wall plate adopts lap joint, and the longitudinal welding seam is butt joint. Vault storage tanks mostly adopt this form, which has the advantage of facilitating the pairing of the wall panels of each circle, and it is safer to adopt the inverted method for construction.
The circumferential welding seam of the linear tank wall plate is the butt joint. The advantage is that the overall diameter of the tank wall is the same from top to bottom, which is especially suitable for internal floating roof storage tanks, but the assembly requirements are higher and the difficulty is greater.
Tank top: The tank top has a number of fan-shaped plates butt welded to form a spherical crown. The inner side of the tank top is made of flat steel to make stiffeners. The lap welds are used between each fan-shaped plate. The whole tank top and the upper part of the tank wall are angle steel The ring (or lock) is welded into one body.
Floating roof
The floating roof storage tank is composed of a floating roof floating on the surface of the medium and a vertical cylindrical tank wall. The floating roof rises and falls with the increase or decrease of the medium storage in the tank. There is an annular sealing device between the outer edge of the floating roof and the tank wall. The medium in the tank is always directly covered by the inner floating roof to reduce the volatilization of the medium.
Tank bottom: The volume of floating roof tanks is generally relatively large, and the bottom plate adopts arched edge plates.
Tank wall: the straight-line tank wall is adopted, and the butt welding seam should be polished smoothly to ensure the inner surface is flat. The upper part of the floating roof storage tank is open. In order to increase the rigidity of the wall panel, according to the size of the wind load in the area, the top of the tank wall should be equipped with a wind-resistant ring beam and a reinforcement ring.
Floating roof: Floating roofs are divided into single-disc floating roofs, double-disc floating roofs and float-type floating roofs.
Single-disc floating roof: a ring-shaped floating ship is composed of several independent cabins, and the inner side of the ring is a single-disc roof. The bottom of the top plate of the single disc is provided with multiple ring steel rings for reinforcement. Its advantages are low cost and easy maintenance.
Double-disc floating roof: It is composed of upper disc plate, lower disc plate and cabin edge plate, and is divided into a number of independent annular cabins by radial partitions and circumferential partitions. Its advantages are high buoyancy and good drainage effect.
Internal floating roof
The inner floating roof storage tank is formed by adding a floating roof inside the vault storage tank. The addition of a floating roof in the tank can reduce the volatilization loss of the medium. The outer vault can prevent rain, snow and dust from entering the tank to ensure the tank The inner medium is clean. This kind of storage tank is mainly used to store light oil, such as gasoline, aviation kerosene and so on. The inner floating roof storage tank adopts a linear tank wall, and the wall panels are butt welded, and the dome is made according to the requirements of the dome storage tank. Domestic internal floating roofs have two structures: one is the same steel floating roof as the floating roof storage tank; the other is an assembled aluminum alloy floating roof.
Horizontal
The volume of horizontal storage tanks is generally less than 100m3 and is usually used in production links or gas stations. The circumferential welding seam of the horizontal storage tank adopts lap joint, and the longitudinal welding seam adopts butt joint. The ring plates are arranged alternately, and the singular number is used to make the end caps have the same diameter. The end caps of horizontal storage tanks are divided into flat end caps and dish-shaped end caps. The flat-end cap horizontal storage tank can withstand 40kPa internal pressure, and the dish-shaped end cap horizontal storage tank can withstand 0.2Mpa internal pressure. The underground horizontal storage tank must be equipped with a reinforcement ring, and the reinforcement is also made of simmered angle steel.