Design of API standard 650 austenitic stainless steel storage tanks
In this project, an area of tank wall is constructed of ASTM A285, Grade C, steel plate that is 5/8-in. thick and has spot-radiographed, double-welded butt joints. The wall is subject to tension in a meridional direction and to compression in a latitudinal direction. The values of R1 and R2 at the point under consideration are 75 in. and 300 in. respectively. A corrosion allowance of 1/16 in. is required. The computed (meridional) tensile stress, stc, in the net thickness after deduction of the corrosion allowance is 6000 lbf/in.2. The problem in this example is to find the maximum allowable (latitudinal) compressive stress value for the given conditions, in conformance with the provisions of API 620 tank standard 5.5.4.5.
The inner layer of API 650 tank is the same as that of single layer tank. It is made of high-quality steel plate in strict accordance with the standard of "steel welded atmospheric pressure vessel". The thickness of API standard 650 austenitic stainless steel storage tanks steel plate reaches the standard and the service life is longer.
Generally, the snow load in the API standard 650 austenitic stainless steel storage tanks construction area should be considered before the design and construction of the tank. The snow load in the API standard 650 austenitic stainless steel storage tanks construction area has an impact on the tank roof design and operation, especially in the area with large snow load, the roof load of large storage tank with large diameter increases. Anti freezing, heat preservation and waterproof measures shall be taken for the additional facilities of storage tanks, such as pumps, breathing valves, flame arresters, detection instruments and thermal insulation layers.