Urgent! What is the flow rate of the gas pipeline?
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Given conditions: The medium in circulation is compressed air; the pipes are made of carbon steel with a DN80 diameter. The total length of the pipeline is 2000 meters, there are 10 90-degree elbows, and the initial delivery pressure is 0.7 MPa. May I ask: with the valve at the end of the pipeline fully open (assuming the pipeline is completely unobstructed), what will be the compressed air flow rate through this pipeline in NM3/h? How to calculate it? I would appreciate guidance from all of you, thank you. This post was last edited by Saint Pa on 2009-2-4 13:05.]
Under compressed air, there is a corresponding pressure; the air flow velocity at that pressure can be determined, and the flow rate can be calculated based on the pipe diameter and flow velocity.
Given conditions: The medium in circulation is compressed air; the pipes are made of carbon steel with a DN80 diameter. The total length of the pipeline is 2000 meters, there are 10 90-degree elbows, and the initial delivery pressure is 0.7 MPa. May I ask: with the valve at the end of the pipeline fully open (assuming the pipeline is completely unobstructed), what will be the compressed air flow rate through this pipeline in NM3/h? How to calculate it? I would appreciate guidance from all of you, thank you. Bro, your question is asking what the pressure requirement at the end point is. Or it could be the pressure drop requirement of the pipeline. Otherwise, it cannot be calculated.
The allowable pressure drop for the pipeline is quite high; an allowable pressure drop can be determined, and by subtracting from this value the resistance loss caused by bends in the pipeline, the frictional resistance loss is obtained. This frictional resistance loss can then be converted into terms related to the friction coefficient of the specific pipe material, as well as the flow velocity based on length and diameter, and from there the flow rate can be calculated
Sorry, a pressure of 0.2 MPa at the end of the pipeline is sufficient; thank you.
The economic flow velocity for gas pipelines is 15–25 m/s
Firstly, the poster claims that the pressure at the end of the pipe is 0.2 MPa; in other words, a pressure loss of 0.5 MPa over a distance of 2000 meters. This is impossible – if the pressure drop were 0.5 MPa, the flow velocity of the fluid would be extremely high. According to what the poster said, with a transmission pressure of 0.7 MPa, the pressure drop in a 2000-m-long pipeline should be around 0.1 MPa. Using tables specific to DN80 pipelines, the volumetric flow rate of the gas is approximately 345 m3/h, which corresponds to a gas flow velocity of about 18 m/s. I obtained the result by looking up a table; of course, it can also be calculated using formulas if the conditions permit.
That’s roughly what happens during the purging process. The flow rate is assumed first, and then the resistance is calculated; once the requirements are met, the flow rate is determined. By referring to the charts, the temperature is estimated to be 20 degrees, the absolute pressure to be 7 kilograms per square centimeter, the pressure drop to be 5 kilograms per square centimeter, and the diameter to be 80 MM. The pressure drop per 100 meters is estimated to be 5/20 = 0.25 kilograms per square centimeter. Using Charts 1 and 3, along with Step 2, the flow rate comes out to be 25 M3/MIN (according to the Chemical Process Calculation Handbook). This corresponds to approximately 1500 M3/H of gas at a pressure of 0.2 MPA, with a velocity of 83 m/s. This post was last edited by Albertlu on 2009-2-5 at 13:42
Given conditions: Flow medium = compressed air. Initial delivery pressure, P1 = 0.7 MPa. DN80 carbon steel pipes, with a total pipeline length of 2000m; 10 90-degree elbows, and 1 valve (the K value varies for each type of valve!) ! ) To obtain the pressure at the end of the pipeline, P2 = 0.2 MPa. Assuming a flow rate Q, the pressure P2’ at the end of the pipeline is determined through hydraulic calculations. If P2’ is greater than 0.2 MPa, the value of Q is increased and recalculations are performed until P2’ equals 0.2 MPa.
The corresponding pipes have specific range of flow velocities; 20 meters per second is generally a suitable value. The flow rate can then be calculated based on the pipe diameter and flow velocity
Thank you all for your hard work! I also learned *some things from the original poster! Thank you
20–30 m/s, I think so.