Main characteristics of horizontal tanks
Lection 1.7. Design of tanks for aviation fuel
Vertical steel tanks
Such type of fuel tanks is widely used for fuel storage. According to the structural variations vertical tanks can be:
- tanks with stationary roof, including tanks with installation for connection of gas space, installation for light fractions recovery;
- tanks with pontoon;
- tanks with floating roof.
Types of tanks are choosen according to flash temperature and saturation vapor pressure of oil products. In addition it is necessary to perform technical and economic calculations.
Advisable types of vertical steel tanks for oil and oil products storage
| Oil products | Advisable types of tanks | ||||
| VST with floating roof | VST with pontoon | VST with connection of gas space | VST with installation for light fractions recovery | VST | |
| Oil | + | + | + | + | - |
| Motor petrol | + | + | - | + | - |
| Aircraft gasoline | - | + | - | - | + |
| Jet fuel | - | - | - | - | + |
| Diesel fuel | - | - | - | + | + |
| Mazut, gas-turbine fuel | - | - | - | - | + |
| Service kerosene | - | - | - | - | + |
| Oil solvents | - | - | - | - | + |
| Oils | - | - | - | - | + |
It is rational to make final decision by comparison of engineering and economical performance of some types of tanks and taking into account operating conditions.
Vertical steel tanks with fixed panel roof is used to store oil and oil products under excess pressure 1962 Pa and vacuum 245 Pa. They are efficiency, not labor-consuming at production; meet the requirements of production methods of construction.
The shell of tank is made of roll blank at the plant. If the size of tank is large, they perform assembly of the separate sheets at the fuel depot area and weld roof directly on the tank.
The roof consists of the rigid panel sectors at the frame. In the tank such roof leans on central support. They construct sloping roof to provide draining the rain water.
Pic. 1. Vertical steel tank for fuel storage with panel roof (v=5000 m3):
1 – shell; 2 – roof; 3 – central support; 4 – stair.
Main characteristics of the tanks with plate roof
| Rated capacity of tank, m3 | Geometrical capacity of tank, m3 | Height of tank, m | Diameter of tank, m |
| 100 | 105 | 5,98 | 4,73 |
| 200 | 206 | 5,98 | 6,63 |
| 300 | 336 | 7,45 | 7,58 |
| 400 | 426 | 7,45 | 8,53 |
| 700 | 764 | 8,94 | 10,43 |
| 1000 | 960 | 11,92 | 10,43 |
| 2000 | 2157 | 11,92 | 15,18 |
| 3000 | 3370 | 11,92 | 18,98 |
| 5000 | 4975 | 14,0 | 20,92 |
| 10000 | 11000 | 17,92 | 28,5 |
| 15000 | 15830 | 17,92 | 34,2 |
| 20000 | 21560 | 17,92 | 39,9 |
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For the regions with gross snow load and snow velocity there are tanks with capacity 10000, 15000 and 20000 m3 which have spherical roof.
Characteristics of the steel vertical tanks with spherical roof
| Rated capacity of tank, m3 | Geometrical capacity of tank, m3 | Height of tank, m | Diameter of tank, m |
| 10000 | 10950 | 11,92 | 34,2 |
| 15000 | 14900 | 11,92 | 39,9 |
| 20000 | 19460 | 11,92 | 45,6 |
Vertical steel tanks with membrane roof are used for mazut and dark petroleum products storage. Such roof is constructed from steel sheets with thickness 2.5-3 mm. It leads on central support and reinforcing ring, which is contour mounted and sags under own mass. Such type of roof allows decreasing the metal consumption up to 40%. But such structure can not be used at the regions with large precipitation.
Today double-wall or double-bottom tanks are used to protect environment from oil spill when the main wall will be damaged. Space between the walls is emergency capacity.
Above ground vertical tank should include the following equipment:
- flame arrester
- access manhole
- breather;
- hydraulic safety valve;
- gauge hatch;
- level gauge;
- siphon valve;
- fuel sampler;
- inlet and suction pipes;
- tank-cap valve;
- tank-cap valve control mechanism.
If equipment has been chosen correctly, it provides reliable operation of tank farm.
Horizontal steel tanks
Horizontal steel tanks differ in volume, geometrical sizes, structure (design of bottom and walls, number of compartments, number of reinforcing rings), equipment.
The advantages of horizontal steel tanks in comparison with vertical steel tanks:
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- industrial production at the plant, that improves quality of works;
- delivery finished tank with equipment at the fuel depot;
- storage of oil under higher excess pressure and vacuum, that decrease fuel losses from evaporation;
- possible underground placement of tanks that decreases area of fuel depot, increases fire safety, provides stability of temperature and eliminates losses of fuel due small breathes.
At the fuel depot and filling station horizontal steel tanks with one, two or three compartments are used. Tanks with some compartments can be used for different grades of fuel. Horizontal tanks can have one or double walled construction.
One walled tank represents itself horizontal cylinder with flat, conical or half-spheric bottom. Tanks with capacity more than 10 m3 are made with intermediate reinforcing rings.
Main characteristics of horizontal tanks
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| Rate capacity, m3 | ||||||
| 3 | 5 | 10 | 25 | 50 | 75 | 100 | |
| Geometrical volume, m3 | 3,1 | 5,7 | 10,96 11,79 | 25,5 26,9 | 54,08 55,46 | 74,6 76,9 | 99,18 101,5 |
| Diameter, m | 1,404 | 1,908 | 2,228 | 2,768 | 2,768 | 3,248 | 3,248 |
| Length, m | 2,03 | 2,03 | 2,83 3,31 | 4,27 4,83 | 9,04 9,6 | 9,05 9,72 | 12,03 12,7 |
Numerator shows data for horizontal tanks with flat bottom, denominator shows data for horizontal tanks with conical bottom.
Double walled horizontal tanks are produced for above or underground placement. Such tanks are equipped with additional devices for filling the space between walls with gas or liquid and test devices for checking pressure between walls.
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