TYPES OF STORAGE TANKS
The ASME Standards or ASME Code (Section VIII) regulates about waste and the manufacture of storage tanks for increased operating pressures of 15 psig.
Storage Tanks areas are mainly used for storage of above 5 psig.
2. Spherical storage tanks
A spherical tank is essentially spherical except it is somewhat flattened. Hemispherical tanks have a cylindrical shell with curved roofs. Spherical tanks are generally used in larger sizes and have internal bonds to support the effort and flow in the frame. These tanks are generally stored products also usaos pair above 5 psig
3. Horizontal Cylindrical Storage Tanks
The working pressure can be from 15 psig to 1000 psig or greater. Some of these tanks have hemispherical head
4. Storage tanks with fixed roof
Are permanently armed tank shell. 500bls soldiers tanks and longer capacity can be provided with Frangible Roof (designed for the care of the cover release them together welded frame occurs when an excess internal pressure), in this case the pressure design pressure shall not exceed the equivalent of the dead weight of the roof
5. Storage tanks with floating roof
This type of tank is mainly used for stores near atmospheric pressure. Floating roofs are designed to move vertically within the frame of the tank to provide a constant minimum gap between product surface and the ceiling and provide a continuous seal between the periphery of the tank and the floating roof. These can be made of a type that is exposed to the environment or a type that is within a fixed roof. The internal floating roof tanks with an external fixed roof are used in areas of heavy snowfall since the accumulation of snow or water affects the operation of buoyancy
Both tanks, fixed roof or internal floating are used to reduce steam losses and preserve the stored fluid.
6. Bolted Storage Tanks
They are designed and arranged as segmented elements which are mounted in locations to provide a complete vertical, cylindrical, above ground, opening and closing the top of the steel tanks. API standardizes Bolted tanks are available in nominal capacity from 100 to 10000 bbls, designed to atmospheric pressure inside the tanks. These tanks offer the advantage of being easily transported and erected at any location manually.
7. Special storage tanks
Storage pipes. Pipe that is used especially for storage and processing components or liquid petroleum gas and ammonia anhydride which should be designed and constructed as agreed with a proper code.
8. Storage tanks flats
When space is limited, as in offshore, these tanks are required flat faces that several cells of this type can be easily built and put into spaces that other types of tanks. Tanks flat or rectangular tanks are normally used at atmospheric pressures.
9. Lined ponds
The ponds are used for the evaporation of liquid waste or storage. Environmental considerations may preclude the use of lined ponds for storing more volatile or toxic fluids. Liners are used pair of losses come from stored liquid, filtering the terrain and possible contamination of groundwater. Clay, wood, concrete, asphalt and metal liners have been used for a long time. Recently, a kind of unexpected materials such liners have been developed using synthetic membranes. Commonly used materials are polivinilillo lining, natural rubber, butyl rubber. Nylon is used to a lesser extent
Some of the most important qualities for a suitable coating are:
* High resistance to tensile strength and flexibility
* Good acclimation
* Immunity to bacteria and fungal attack
* Specific gravity greater than 1
* Resistant to ultraviolet light
* No physical imperfections and defects
* Easily repairable
The leak detector must sometimes be built into this system – tank, especially when toxic wastes which are stored. The types of leak detection systems are commonly used are: drainage, underbed, soil resistivity measurements and monitoring wells as well as combinations of these
10. Storage pits
Similar as above but is only used in a basic emergency. The use of these types of storage systems are limited by government regulatory agency.
11. Underground storage
It is more advantageous when you need to store large volumes. Is very advantageous when you have a high vapor pressure of the product
Underground storage types are: construction of salt caverns by solution mining of minerals or conventional, rock caves built by conventional mining nonporous, caverns developed for the conversion of coal, shale or mineral salt
12. Solution mined caverns
The caverns are constructed by drilling a well or drilling inside the salt caverns and salt water circulating inside the reservoir of salt to dissolve it. The caves can be operated by movement of brine, removing the cavity, by displacement of vapor or gas in case: for expansion
More solutions mined caverns are operated using the technique of displacing brine. The pipe string displacement is installed near the depth of the cavern and the product is injected into the annulus between the tubing and casing displacement forcing the brine to rise. This procedure is used for product recovery. In this type of recovery a reservoir of brine is usually provided.
13. Conventional mined caverns
Can be built somewhere in nonporous rock if it is available to the proper depth so that the product will stand the pressure. More caves containing products are built in shales, clays, dolomite or granite. This type of cave is operated dry (the recovery of the product is made by pumping).
14. Cooling Storage
The decision to use storage in a pressurized cooling is generally a function of the volume of liquid to be stored, the filling rate of physical and thermodynamic properties of the liquid to be stored and investment capital, and expresses each systems to be used
The parameters involved in the selection of the facilities for optimum cooling storage are:
* The quality and product quality to stored
* The filling rate, temperature and pressure inflow
* Product shipping conditions
* The composition of the product
* Available cooling medium (air, water, etc.).
* Availability and cost of utilities
The proper choice of the proper storage and integration of the storage facility with refrigeration storage facility is important for the total economy in the initial investment and operating costs.
When using storage for cooling, the liquid to be stored is usually cooled to the dew point temperature at atmospheric pressure. Refrigerated storage tanks normally operates at an internal pressure of 0.5-2Psig
Cooling requirements typically include the following functions:
* Cooling the filling stream to storage temperature
* Products of liquefaction re vaporized by heat leaks in the system
* Liquefying vapors displaced by the liquid
* Other factors that should be considered are:
* Requirements of the pump energy
* Changes in barometric pressure
* Product Composition
* No condensable
* Effects of solar radiation
* High Temperature Products
The rationale for the various types of cold storage of boats have the same designs as the basis for common expectations and pressure cylinders. A caution should be noted. More liquids at low temperatures are lighter than water and the boats are designed to store these liquids lighter. Therefore, it is common practice for the design basis for the total weight of product content and for the vessel containing water, that is to have a rate of 1.25 times the weight of the product.