A516 grade 70 plates API 650 unanchored tanks

In the petrochemical industry and other industries, large vertical API 650 unanchored tanks are often used to store various production raw materials. Usually, the medium with high melting point and easy to crystallize at room temperature can be exported and used after heating, which involves the heating of large vertical storage tanks. The heating system is an auxiliary facility for heating of large vertical storage tank. It is often necessary to design external heating coil or internal heating coil system.

In this project, a cylindrical tank 62 ft 6 in. in diameter is designed for an internal pressure of 4 lbf/in.2 gauge in the vapor space. The plate material is ASTM A131 steel with appropriate grades for different plate thicknesses in accordance with Table 4-1 for a design metal temperature less than 65°F but not less than 25°F. No corrosion allowance is required for any portion of the tank. The top course of the butt-welded cylindrical sidewall is 1/4 in. thick. The roof is a single lap-welded spherical dome with an internal radius of 50 ft and a thickness of 1/4 in. The maximum design liquid level is 6 in. below the plane of the juncture of the tank API 650 unanchored tanks roof and sidewall.

Compared with the fixed roof API 650 oil storage tank without API 650 unanchored tanks floating roof, there is no evaporation space. In principle, this eliminates the so-called "large breathing loss". Evaporation not only causes the loss of product quantity, but also affects the quality of API 650 unanchored tanks product and pollutes the environment.