Selection of breather valves for internal floating roof storage tanks
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This post was last edited by Asuka sky on 2021-4-17 at 16:10. Overview: A floating roof tank equipped with an oil and gas recovery system, as well as mechanical vent valves and single vent valves. Is the nominal diameter of the breathing valve in the table below too small? What if the medium is changed to gasoline?
As long as it can handle the traffic, isn’t a smaller diameter cheaper?
The flow rate is calculated using API2000; you can find the formula in my post
Why are the diameters of the breathing valve and the single-exhalation valve different? The breathing valve opens during inhalation (negative pressure), while the single exhaust valve opens during exhalation (positive pressure in the tank). Since DN80 can meet the requirements, why is the diameter of the one-way valve DN200?
I don’t know who calculated the diameter for you; different pressures result in different diameters
The diameter of the breather valve is too small; a DN200 valve is required to meet both the exhalation and inhalation flow requirements.
This requires calculation; you can ask the design firm for it.
The diameter of this DN80 vent valve is too small. According to API2000 and SY0511.1, not only the amount of liquid that enters and exits the tank through the vent needs to be taken into account, but also the amount of heat-related gas movement within the tank, which cannot be ignored. For a tank with a capacity of 1000 cubic meters, a vent valve with a diameter of at least DN150 is required; for a tank with a capacity of 5000 cubic meters, two DN200 vent valves are necessary. It is common for the tank to become deflated, so it is necessary to use larger vent valves. The single exhaust valve takes into account gas resistance and pressure loss. Larger is also better
For internal floating roof storage tanks, can the thermal breathing volume of the tank be ignored?
Do all current internal floating roof tanks have to be equipped with a nitrogen seal?
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