Issue with the amount of nitrogen gas used for purging

The nitrogen purge flow rate is generally required to meet the gas flow velocity within the purge pipeline.

Select the gas flow rate of nitrogen based on pressure, and then the flow rate can be determined based on the pipe diameter

Reply to 2# wwyyahhb: I’m not sure what the appropriate flow rate should be

The diameter of the flare pipe is fixed; the nitrogen flow rate can be calculated based on the nitrogen pressure required for purging

Reply to 4# flyingpetty: Generally, 7–20 m/s is recommended for reference.

Give the answer downstairs! ! ! ! ! ! ! ! ! ! ! ! !

This flow rate is too high. The information I saw is not like this

To ensure the safe operation of the flare gas discharge pipeline network, a fixed purging facility is installed at the farthest point upstream of the flare gas main; this facility includes a flow meter, a check valve, and a manual control valve. The purge gas is usually nitrogen or fuel gas; however, for low-temperature pipelines, the purge gas must not condense at the lowest temperature. In such cases, nitrogen is generally used for purging. The flow rate of the purge gas inside the largest flare tube is 0.03 m/s, while if the flare system is equipped with a water (liquid) seal, the flow rate of the purge gas upstream of the seal is 0.01 m/s. For low-temperature flares and hydrogen-rich exhaust gases, the purging speed must be increased. In the absence of a water seal, the purge gas should be the heaviest available gas, and a low-flow alarm as well as a low-pressure alarm to indicate vacuum level should be installed to prevent air from flowing back into the flare system.

Is 0.03 m/s too slow? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

It generally depends on the design pressure of the system; once a certain pressure is reached, that’s sufficient