API 650 ground supported flat-bottom tanks roof manholes

The water dissolved in the oil will be separated out from the oil stored in the API 650 ground supported flat-bottom tanks for a long time, and the acidic water layer will appear at the bottom of the API 650 ground supported flat-bottom tanks for a long time, which will accelerate the corrosion of the API 650 ground supported flat-bottom tanks and cause the wall thinning and even leakage. With the increase of service life, the API 650 ground supported flat-bottom tanks must be inspected and cleaned regularly to check the hidden danger.

The thickness of the API 650 ground supported flat-bottom tanks annular bottom plates shall be in accordance with Table Q-4 (for steel or aluminum, as applicable). The thicknesses shown are minimums. The ring of annual plates shall have a circular outside circumference, but it may have a regular polygonal shape inside the tank shell with the number of sides equal to the number of annular plates. These pieces shall be butt-welded in accordance with Q.7.1.1, Item b. The plates of the first shell course shall be attached to the annular bottom plates by a weld as required by API 620 oil tank 5.9.5 except when a full-penetration weld is used or required (see Q.7.1.1). Butt-welds in annular plates shall be not closer than 12 in. from any vertical weld.

In API 650 oil storage tank, when the mixing ratio of combustible medium and air reaches a certain limit, it is easy to cause explosion. Therefore, it is necessary to add API 650 ground supported flat-bottom tanks external floating roof to open cylindrical steel API 650 ground supported flat-bottom tanks tank. At present, the external floating roof is most suitable for large-scale API 650 oil storage tank in China, ranging from 20000, 30000, 50000 cubic meters to 100000 cubic meters.