Hi
I 've got a system with three PRV's on a manifold with a design temperature of 218C & operating temp of 178C. The PRVs are handling a vapour from the top of a tower and are situated on the tower top platform and are discharging directly to atmosphere and the pipework expands from 8" at the discharge quickly up to 18".
In the absence of more informed process information, what would be a reasonable temperature to use to model the discharge pipework?
Operating temperature seems a bit conservative, given the valves should not be relieving for that long and are open to being 'cooled by the breeze' as someone put it; also the rapid expansion of the gases will probably result in a drop in gas temperature, so I'm considering using 80C as a half way between ambient and operating.
With such a small valve [6" x 8"] and large tailpipe I'm struggling to get the moments down on the valve itself as any expansion in the inlet leg is not matched by that in the cold trunnion under the discharge elbow. The differential expansion isn't much, but it is generating very large moments.
Any thoughts on either of these issues anyone?