Storage tanks design

Vapor pressure has also become a means of regulating storage tank design by the EPA. Because increasing vapor pressure tends to result ia an iacrease ia volatde emissions, the EPA has specific maximum values of vapor pressure for which various tank designs may be used. 

The system is a storage tank designed to hold a flammable liquid under a low positive nitrogen pressure (see Figure 5.1). This pressure is controlled by PICA-1. A relief valve is fitted which operates if overpressurization occurs. Liquid is fed to the tank from a tank truck, and is subsequently supplied to the process by the pump P-1. 

Storage Tanks Design Separation, Inerting, Escape Aids... 

Atmospheric tank—a storage tank designed to operate at any pressure from atmospheric up to 3.45kPa gage (0.5 psig). 

Low-pressure tanks—a storage tank designed to contain material at pressures above 3.45 kPa gage (0.5 psig) but not to exceed 103.4 kPa gage (15 psig). 

Case Study — Nitric Acid Storage-Tank Design... 

Y. Amrouche, C. Dave, K. Gursahani, R. Lee, and L. Montemayor, General rules for aboveground storage tank design and operation, Chem. Eng. Progr., 54-58 (December 2002). 

Storage of liquid materials in a typical process industry is carried out in tanks classified as spherical or vertical and horizontal cylindrical. Since safety is an important consideration in storage tank design, the National Fire Protection Association and the American Petroleum Institute publish rules for safe design and operation. Vertical tanks are most commonly used for outdoor storage for such materials as petroleum products. Water towers are typical of elevated vertical tank outdoor construction. They are used for maintaining a uniform head of water to store water for temporary emergencies and for fire protection. Hori-... 

On completion of transfer, this gas pressure will immediately be felt in the storage tanks. For compressed air discharge it is recommended that tanks be designed to 2.4 bar absolute and tested to 3 bar absolute. Storage tanks designed to accept compressed air discharge from tankers must always be splash filled. The ideal capacity for a storage installation is two weeks use plus one tanker load (18 tons). 

Further information related to the in-containment refuelling water storage tank design can be found in Section 6.3.2.2.3 of Reference 6.1. 

In storage tanks, design plays an important role. Which one of the following should be a major consideration ... 

American Standard API 650 (American Petroleum Institute 2007) uses a similar concept to account for the capacity of the tank to dissipate seismic energy through the so-called response modification factor or simply reduction factor, denoted by R. The response modification factor for ground-supported, liquid storage tanks designed and detailed to these provisions shall be less than or equal to the values shown in Table E-4 of API 650. 

A hydrocarbon liquid is stored at 25°C in a 30,000-m storage tank designed according to API standard 620 for the pressure of a 400-mm water column and vacuum of a 200-mm water column. The tank is maintained with a nitrogen atmosphere. The maximum pumped-in rate is 50 m /h and the pump-out rate is 40 m /h. What will be the size of the vent Assume the flash point is 20°C, fire venting is not required, and the atmospheric pressure is 100 kPaA. 

---