9. Storage Tanks

Tanks and Storage Equipment General Storage of liquid materials is commonly accomplished in industrial plants by use of cylindrical, spherical or rectangular tanks. These tanks may be constructed of wood, concrete, or metal, with metal being the most common material of construction. The design of storage vessels involves consideration of details such as size and number of openings, shape of heads, necessary temperature and pressure controls and corrosive action of the content. The necessary wall thickness for metal vessels is a function of: The ultimate tensile strength or the yield point of the metal at the operating temperature. The operating pressure

Tanks and Storage Equipment General The ultimate tensile strength or the yield point of the metal at the operating temperature. The operating pressure The diameter of the tank Joint or welding efficiency Various codes are available which specify the conditions that must be met for different vessels.

STORAGE TANKS Storage tanks can be divided into the following types: Atmospheric storage Pressure storage Refrigerated storage

1. Atmospheric storage Tanks - Applied to tanks operating at or near atmospheric pressure. - They are used to hold liquids which will not vaporize at ambient temperature.

Storage Tanks - Atmospheric Tanks Atmospheric tanks are categorized primarily as follows: 1. Open top (no roof) - has no roof and may store or process non-volatile liquids such as water, brine, etc. 2. Fixed roof - Fixed roof tanks, such as cone roof or umbrella roof are used to store low vapor pressure liquids which will not vaporize at temperature below 120oF. - Generally used for gas oil, water, chemicals. 3. Floating roof - Floating roof such as hard top pan and pontoon roof types eliminate the vapor space above the liquid, allows storage of higher vapor pressure materials. - Generally used for crude oil, gasoline, napthas

Hard Top Fan Floating Roof Tank

Storage Tanks - Pressure Storage Tanks – applies to vessels designed to withstand pressures sufficient to keep liquid stored from vaporizing. Used for high vapor pressure liquid such as butane, propane etc. Spheres - Generally used to store high vapor pressure liquid Advantage is that it can contain the greatest amount of liquid for a given amount of steel. - A sphere can also withstand greater pressures with a given plate thickness than cylindrical vessels.

Storage Tanks - Refrigerated Storage Tanks - refers to low temperature/cryogenic storage - This type is used for gases that liquefy under pressure at atmospheric temperature. - In cryogenic storage the gas is at, or near to, atmospheric pressure and remains liquid because of low temperature. Cryogenic refers to temperature below -10oC

Storage of Gas Bulk transport of fluids 1. Pipe lines 2. Tank cars (railroad) 3. Tank trucks 4. Portable tanks, drum, or bottles 5. Sea going tankers 6. Container ship