9. Storage Tanks

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9. Storage Tanks
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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

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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.

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STORAGE TANKS

• Storage tanks can be divided into the following
  types
• Atmospheric storage
• Pressure storage
• Refrigerated storage

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Storage Tanks

• 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.

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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

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Hard Top Fan Floating Roof Tank
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Storage Tanks - Pressure 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.

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Storage Tanks - Refrigerated Storage Tanks

• 3. 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

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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