Flow rate behind the self-acting nitrogen control valve
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I am purchasing a self-acting control valve for nitrogen sealing in atmospheric pressure storage tanks. The valve manufacturer stated that the flow rate downstream of the valve is required; how is this flow rate determined?
For storage tanks that require nitrogen sealing, what is typically the maximum flow rate of the pump at the liquid outlet? . That’s the flow rate downstream of the valve. . Occasionally, it is necessary to consider the changes in gas volume caused by temperature differences.
One should not talk about the flow rate downstream of the valve; when selecting a control valve, whether it is a self-acting type or a control valve, what matters is the pressure downstream of the valve. The flow rate, after being converted to standard units, remains the same before and after. As mentioned above, the normal flow rate for nitrogen sealing is generally the normal flow rate of the discharge pump, while the maximum flow rate is that of the discharge pump’s maximum capacity. If the maximum flow rate of the pump cannot be determined accurately, 1.2 to 1.5 times the normal flow rate can be taken as the maximum flow rate.
For self-acting control valves, it is necessary to specify the operating temperature, pressure before the valve, allowable pressure drop, normal flow rate, and maximum flow rate
The discharge flow rate of the pump + the volume change of the gas phase caused by temperature changes (very small and negligible)
For Fisher manufacturers, if the customer does not provide the flow rate, it can be calculated based on the feed volume to the tank and the tank’s capacity, using API 2000 as a reference