Design codes for gas pipelines and flow velocity issues in hydrogen pipelines
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Hello everyone! Let me first explain the situation: 1. The installation may need to be modified. The gas pipeline in question has a diameter of DN350, is made of carbon steel, and is nearly 4 kilometers long. The pressure of the gas is around 0.5 MPaG, with a flow rate of approximately 30,000 Nm3/h. The temperature is at room level, and the gas contains about 60% hydrogen, along with light hydrocarbons, nitrogen, carbon dioxide, carbon monoxide, hydrogen sulfide, and other components. My first set of questions is: What criteria should be checked (standard numbers or keywords)? What is the maximum allowable voltage drop? The calculated flow velocity is close to 90 m/s; does this meet the requirements? 2. Hydrogen with a purity of 99.9%, at a pressure of 2.4 MPaG and a flow rate of approximately 14,000 Nm3/h, at room temperature; the pipeline is DN200 and made of carbon steel. The calculated flow velocity is 102 m/s, whereas according to GB50177-2005, this value should not exceed 20 m/s – thus it clearly does not meet the standards. So for the second set of questions, why would the design institute design it in this way? Thank you all for your advice:hug:
No, for 2.4 MPaG carbon steel hydrogen pipes, the flow velocity must not exceed 15 m/s; I got it wrong. . .
This post was last edited by ylb913 on 2016-3-2 at 10:42. You’ve miscalculated; the flow rate should be determined based on the volumetric flow under actual operating conditions, not according to the nominal values. 0.5 MPa should be calculated as 0.6 MPa in terms of absolute pressure, assuming a temperature of 37 degrees and a flow velocity of 16.4 m/s. The other one is 5.6 m/s.
Did the design institute not conduct its own calculations?
As mentioned on the third floor, it should be calculated based on actual operating conditions. I have always believed that mistakes do occur in design firms, but they are by no means common; when problems arise, one must first look for reasons within oneself.
I just came back and realized that I had made a bunch of mistakes in the data – the diameter was written as DN350 instead of DN250
Well, I thought what was specified in the standards referred to the flow rate at that pressure; it was originally said to be the flow rate at standard pressure
This post was last edited by HEJIYUER on 2016-3-3 22:22. H2 tubes are different from O2 tubes. The H2 pipeline is under positive pressure, and there’s no O2 inside; after all, combustion requires three elements – so how can it be \"sealed\"? There’s no need to be restricted by 20M/S, right?
Check the design specifications for hydrogen stations; it seems to be GB 50177. These specifications specify different maximum flow rates for hydrogen at various pressures. The 20 m/s here is a mistake on my part; at pressures of 0.1~3.0 MPa, the maximum flow velocity is 15 m/s.