http://www

http://www.cheresources.com/invision/topic/20221-psv-sizing-fire-case-supercritical/The equations from API for supercritical fluid can be used.

Note the relief temperature calculated using the API equation is normally really conservative because is assumes ideal gas law.

I normally use HYSYS to determine the relieving temperature. Take a copy of your stream at normal operating conditions. Change the pressure of the copied stream to relieving pressure. Then use an adjust to change temperature so that the volume is the same as the stream at normal operating conditions.

This will give you a more realistic relief temperature for supercritical fluid.

cheers