Seeking advice on valve selection for 80% hydrogen-containing media
Thread Content
Dear experts: I have a question. For the purge valve of the PSA pressure swing adsorption feed gas, the flow rate has reached 280 m/s, and the manufacturer says that it’s fine to operate it at this level. Is this really safe? Component content (V%) Flow rate (Nm3/h) H2: 0.95 28332.5 N2: 10.53 3685.5 CO2: 0.46 861 CO: 4.90 1715 Ar: 0.00 0 CH4: 1.15 402.5 Methanol: 0.00 0 Water: 0.0000 0 Total sulfur ≤0.1 ppm 0 Flow rate (Nm3/h): 35000 Temperature: 40℃ Pressure: 3.6 MPa (G)
Not only is it necessary to reduce pressure, but noise reduction is also required; the material for the sealing surface must be chosen carefully
It’s too high; the 150 limit in the table is a reasonably appropriate value
The flow rate is too high; the flow velocity through the control valve exceeds 0.3 Mach. I recall that in such cases it’s necessary to install special valve internals or select a different valve model
This post was last edited by white-cg on 2022-5-22 08:29. Noise reduction requires reducing the voltage step by step as well as slowing down the speed. A DN150 valve, CV135, capable of accommodating complex valve internals. The 316 valve stem is a bit thin. What was said upstairs is correct; below 0.3 Mach is the best. Maximum shut-off pressure difference: it is advisable to choose 5 MPA. 1. Drilling, with 2–3 layers of cages. 2. Labyrinth design; the medium must be clean to avoid blockages. 3. Axial flow multi-stage valve internals, with a sugar-coated hawthorn structure
The flow rate shown in the diagram is on the high side; if the manufacturer has proven track record of using this solution, then it can be employed. The multi-stage pressure-reduction valves shown in the diagram likely feature a 2-to-3-layer cage structure, which makes them much cheaper compared to other types of structures. You can ask them about their past performance and usage history.