Do buried pressure vessels, as special equipment, require sand removal for annual inspections?
Thread Content
Our factory currently has an underground storage tank area with around 40 tanks, each with a capacity of 200 cubic meters. The tank area is quite large, and the material is discharged using nitrogen pressure; therefore, these tanks are considered pressure vessels. If macroscopic inspections as part of the annual inspection for special equipment require the tanks to be dug out, the costs would be high. In such cases, it would be necessary to consider switching to self-priming pumps for discharging the material, and classifying the tanks as ordinary pressure vessels for inspection. Is it really necessary to make such a change?
Under normal conditions, the pressure is maintained at 0.35 MPa; pressure is only released when unloading, otherwise the volatilization rate would be too high
This post was last edited by Zhou Junhao on 2022-7-21 at 16:58. Maintaining a pressure of 0.35 MPa is necessary for discharging the material; if a self-priming pump is used, then it is sufficient to apply a nitrogen seal to the tank. It’s just not possible to have it such that nitrogen is introduced during discharge and then the nitrogen pressure is released after the discharge is complete. Because doing so results in too high a volatilization rate, and the exhaust gases cannot be treated
In other words, a pressure of 0.35 MPa needs to be maintained at all times; the pressure drops only during unloading. But after unloading, is it still necessary to fill the tank with nitrogen to restore the pressure to 0.35 MPa? Or should we ignore for now how much the pressure drops during unloading, and increase the pressure again during the next unloading and material transfer?
It means filling it with nitrogen to maintain pressure right after unloading the cargo