I have a question, I have to calculate a relief valve size for my compressor suction drum, which has the fire case. The relief pressure is higher than the critical pressure of the fluid, is there any procedure to calculate the relief temperature?

What is it that you exactly have?

You infer you are protecting a compressor suction drum from a pool fire. Compressors compress gas, not liquids. By the title of the thread, are you stating that you are compressing a supercritical fluid? Which one, and what are its conditions?

What kind of compressor is this? Is its MAWP higher than the critical pressure of the fluid (gas?)? Kindly identify the fluid and all the rest of the basic data and don’t leave us in suspense.

Please find the attached link,
http://people.clarkson.edu/~wilcox/Design/reliefv2.pdf

This gives a procedure to do the RV sizing for super critical condition. You will require hysys or other simulation software to do the property calculations. At relieving condition the fluid will be in dense phase & the orifice size calculated will be lower (may be D or E orifice).

We have came across similar situation many times, at normal condition the gas in KOD will be below critical condition but at relieving condition (ie. 21% over pressure {for ASME section 8 vessel} & corresponding relief temperautre ) the fluid will be above critical condition.

regards
Umesh.R

Thanks Umesh,
It was useful and exactly what I was looking for.