A131 grade A plates API 650 duplex stainless steel tanks

The safety inspection of atmospheric storage tank, API 650 duplex stainless steel tanks is divided into external inspection, internal and external inspection and comprehensive inspection. External inspection shall be conducted at least once a year, internal and external inspection shall be conducted at least once every three years, and comprehensive inspection shall be conducted at least once every six years. The safety inspection of large atmospheric storage tanks, API 650 duplex stainless steel tanks requires special attention: the parts where the liquid level often fluctuates, the parts that are susceptible to corrosion, and the parts that are deformed and worn during use should be checked.

API 620 Crude Oil Tank Pneumatic Pressure
An air pressure equal to 1.25 times the pressure for which the vapor space is designed shall be applied to the enclosed space above the water level. In the case of a double-wall tank with an open-top inner tank, where the air pressure acts against the outer tank and the inner tank is thus not stressed by the air pressure, the inner API 650 duplex stainless steel tanks may be emptied of water before the pneumatic pressure test begins. The test pressure shall be held for 1 hour.

API 650 petroleum storage tank pipeline stress and product pressure, tank pressure, uniform or non-uniform temperature difference between the tank wall and the tank bottom, which cause the radial displacement and longitudinal rotation of the API 650 duplex stainless steel tanks tank wall at the opening to affect the oil tank wall The impact is obvious. Therefore, the design must ensure that the load applied by the external pipeline on the opening of the tank wall is within the safety limit. If the stress of the API 650 duplex stainless steel tanks connecting piping is not handled properly, the wall of the API 650 petroleum storage tank may deform or even rupture, causing a major accident.