Carbon dioxide pressure relief valve
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Add a carbon dioxide pressure reducing valve to the process unit. 7.0 Mpa at the valve inlet and 80°C; 3.5 Mpa at the valve outlet. I remember that if the pressure drop of carbon dioxide is too rapid, dry ice will be formed; I can’t recall the exact values though It was originally a sleeve type, but I’ve changed it to a corner valve now, as the flow path is larger that way. I would like to ask the seniors here: have you used such valves before? Will it turn into solid carbon dioxide? If that’s not possible, it will have to be done in two steps to reduce the pressure.
I want to know that too, just waiting :lol
This operating condition can’t be right. I remember that the outlet pressure of the CO2 compressor in the urea plant is around 11 MPa, and a needle valve is used as the backflow valve; the pressure difference across this valve is also several MPa. If freezing occurs so easily, how does this valve prevent surging?
Thank you. I have discharged it through the pressure tap of the pressure transmitter; the pressure was around 6 Mpa or so. It will freeze. For anti-surge, a large amount of air enters at the inlet, right? The temperature won’t drop that fast, right?
The poster needs to have a specialist in process engineering do the calculations (a simple process case): determine how much the temperature will drop after pressure reduction, and whether freezing will occur; this also depends on the temperature of the CO2 upstream. Additionally, it is also useful to check what material the pipe behind the valve is made of. It’s not necessarily multi-stage; the pressure reduction value is determined by the process, and thus the temperature drop value is also fixed.
That makes sense; indeed, the design should be carried out only after the process has been confirmed, as we are unable to calculate the heat release energy or the changes in the medium.