Selection of storage tank breather valves
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When selecting a breathing valve for oil storage tanks, should the specification of the breathing valve (i.e., the diameter of the connection flange) be determined based on the flow rate of oil in and out of the tank, or based on the tank’s breathing volume?
Personally, I think it should be chosen based on the amount of breathing!
The selection is based on the volume of ventilation, which can be calculated in accordance with relevant regulations; its main component is the maximum amount of oil that enters or leaves the tank per unit of time.
Reply to 3# Childhood: The maximum flow rate for entering or leaving the oil tank refers to the larger of the values for entry and exit, right? I’ve also seen some information suggesting that the model and quantity of vent valves should be chosen based on the inflow and outflow rates of the oil tank – is this based on experience?
I have always thought that the selection should be based on the breathing volume of the breather valve. I saw this thing online yesterday, so I was confused and came here to ask the experts for guidance! ! ! Oil tank oil inflow and outflow rate (m3/h), number of breather valves, specifications of breather valves
There is nothing wrong with this table; it is based on empirical experience and can be used as a reference. But strictly speaking, the selection of a breather valve requires calculating the breathing volume first. The exhaust volume and intake volume of storage tanks need to be calculated separately, with the American Petroleum Institute Standard 2000 serving as a reference for these calculations. In addition to considering the amount of material entering and leaving the tank, it is also necessary to take into account the amount of evaporation and condensation that occurs to the material inside the tank due to changes in temperature. If the tank is equipped with a nitrogen purge system, then the pressure of that nitrogen purge system must also be considered, and so on.
In other words, the exhalation volume and inhalation volume are calculated separately, and then the specification of the breathing valve is determined based on the larger value, right?
On the upper floor, both the exhalation volume and inhalation volume correspond to the respective exhaust or inhalation pressures specified as criteria for selecting breathing valves
For the calculation of the ventilation volume of breather valves, as well as the determination of their quantity and size, refer to the \"Design Code for Tank Areas in Petrochemical Storage and Transportation Systems\" SH3007-1999
When selecting a breathing valve, the following factors are primarily taken into consideration: 1. The increase in the amount of liquid that evaporates inside the tank due to heating during a fire, which in turn leads to an increased rate of vapor release. 2. Under the influence of climate, the increase in vapor pressure inside the tank decreases, thereby reducing the heat effect associated with respiration. 3. In cold regions in the north, a waterproof breathing valve should be selected. 4. Maximum liquid volume for entering and exiting the tank.
There are specific calculation criteria, which I can’t remember now. If the storage tank is large, it is necessary to select an appropriate size for the vent valve based on temperature changes in the surrounding area and variations in the vapor pressure of the material. Additionally, the flow rates of inlet and outlet materials must also be taken into consideration to determine the appropriate size of the vent valve, thereby preventing the storage tank from experiencing negative or excessive pressure