Problems encountered when reducing 8 kilograms of steam to 2 kilograms of steam – discussion
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Dear Haihao friends: My installation is currently facing a problem – I need to reduce the pressure of 8 kg/cm² steam in pipes with a DN40 diameter to 2 kg/cm² superheated steam; the pipes in question have a DN80 diameter； The requirement is that the flow rate of the superheated steam after pressure reduction should be between 700 and 1000 kg/h. The question is: 1. Can the flow rate meet this requirement after pressure reduction? 2. What is the temperature approximately when 8 kilograms of steam is reduced in pressure to 2 kilograms of superheated steam? Do I need to provide any more data? Looking forward to discussion
1. It should be able to meet the requirements； 2. The temperature of 8 kg of steam before pressure reduction; when the pressure is reduced to 2 kg, assuming no external heat loss, the temperature should remain the same as it was before the pressure reduction ； For saturated steam, the temperature corresponding to 8 kilograms is around 175°C; it should also remain at 175°C when the pressure is reduced to 2 kilograms. However, due to heat loss to the outside, the actual temperature is not that high. My personal understanding, for reference only.....
The temperature of saturated steam after pressure reduction is approximately 155°C; see the figure below for details
Why is the pressure of this 8-kilogram steam 885 kPa? Also, may I ask, what is the name of this software? Thank you
1) The 8-kilogram pressure we often mention generally refers to gauge pressure, and when converted to absolute pressure, it amounts to 885 Kpa; 2) This software is VMGSim
Does the temperature remain unchanged after pressure reduction? It’s strange; shouldn’t it decrease?
What you mean is temperature and pressure reduction; there is also reduction in pressure alone without a reduction in temperature
How to achieve reduced pressure without a decrease in temperature? Forgot to ask for advice
A pressure relief valve assembly will suffice; for temperature and pressure reduction, a cooling water system is also required
There is a throttling effect, right? When gas expands through throttling, its temperature generally drops. For example, the temperature was calculated to be 155°C on the 3rd floor, but my simulations showed 167°C. In any case, the temperature decreases; I’m not sure how it’s possible to avoid this temperature drop by using only a pressure reducing valve.