Posted by Tony Conner on August 29, 2001 at 08:35:06:
In Reply to: Re: condensate return from the main steam header posted by ED MATTHEWS on August 29, 2001 at 07:44:46:
The safety valve(s) on the DA will determine what's going on there. It's unusual for most industrial DAs to run more that 5 - 10 PSIG, with the safety valve set for 15. The safety valve capacity will have to be enough to handle all of the steam the PRV(s) can pass, and any other steam sources like turbine exhaust, HP returns, etc. It's very unlikely that this one little trap will tip you over the edge. It likely should be a little trap, too. I see a LOT of monster 2" traps installed where they're not needed. They cost a bundle, and wear out before their time. Take the time to size the trap properly - you'll probably be surprised by just how small it needs to be.
It doesn't hurt to check DA safety valve capacities as well. I see quite a number of DAs that have only the factory mounted safety valve installed. The DA manufacturer has no way of knowing what the maximum potential steam flow might be. I think everyone would be better off if they didn't supply these little safety valves, as it just confuses people, and gives a false sense of security. I've seen DAs with about 15% of the required safety valve capacity installed and running. The safety (supplied by the manufacturer) lifted at 15 PSIG, but only passed 1,240 #/hr. The 2" PRV "sized" by the engineer, and installed by the contractor could potentially pass over 8,000 #/hr. There's a lot of scary stuff out there.
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