Steam Pressures
Steam Pressures
(OP)
I am working on a system and I have 60 psig steam available. All of my components, HX's, coils, etc can be operated at this higher pressure. However, my previous experience (every steam system I have come across the steam was transported at a higher pressure and used at a lower pressure) and everything I read on the subject indicates that I should put in the PRV station and reduce the pressure to 15 psig. But none of it really says why, it just says do it. In this particular case I really don't want to because of overall floor space constraints. It also seems (i haven't done the calcs) like it's wasting energy since you lose energy in the pressure reduction without any work being done. However, I feel like I'm missing something big in using the 60 psig steam vs the 15 psig. Can anyone enlighten me?





RE: Steam Pressures
In a pressure reducing valve the upstream and downstream enthalpies are the same.
RE: Steam Pressures
Are there any additional installation considerations that need to be made because I am using the 60 psig steam? ASME ratings, service issues, etc. None of my literature addresses any of that.
RE: Steam Pressures
RE: Steam Pressures
What I'm really after is if the design properly incorporates using the 60 psig steam (equipment has been selected at the higher operating condition, i can get the required performance, pipe is selected properly, I am properly insulating for the higher temperature, etc) is there a really good reason to add the PRV station and reduce to 15 psig?
My reps are very accomodating but technically in this manner they have not been of much help.
Your first answer seems to indicate that I would be using more energy since the enthalpy of the steam doesn't change and the equipment is actually more efficient at the lower pressure. (I am doing some calcs and revising some selections to quantifiy this in relation to my design). Are there any other issues outside of this i.e. service, safety, etc that I am missing?
RE: Steam Pressures
Conversely, If the steam pressure is lower than the water pressure in the tubes of the heat exchanger, then in a failure you will get flow out of the tubes, into the exchanger and then through the steam trap (maybe some waterhammer, much less dangerous).
RE: Steam Pressures
Regards,
SNORGY.
RE: Steam Pressures
RE: Steam Pressures
15 psig steam problems are a lot less severe than 60 psig problems.
RE: Steam Pressures
I have found life is easier with the lower pressure, less water hammer and such, condensate receivers and pumps are in a more comfortable operation zone, steam is a gentle mist, not a roaring, invisible safety hazard.
RE: Steam Pressures
htt