Dear All
I encounter with two issues in design of purge gas and closed drain system as follow:
1.there are to train of compression.one of them has been designed to handle sweet gas.another one has been for sour gas compression.
the K.O. drums which has been considered for each service connected to a common closed drain deemed for sour service (Nace).
material of drain line introduced from K.O. drum in sweet service has not been considered per NACE. requirement since the fluid does not contain H2S.Since the Closed drain is Nace, how this spec break shall be considered? my question is about any segregation facility such as considering check valve,globe valve, ball valve and spectacle blind and also location of spec break
2.Dry, sweet fuel gas has been considered for purging of compressors inlet and outlet piping.in high pressure compressors served in sour service, there are possibility of fuel gas contamination due to misdirection (back flow) from process line to fuel gas stream.in addition the aforementioned issue (NACE requirement) will bother fuel gas system since its material has been considered for sweet service.my question is about any segregation facility such as considering check valve,globe valve, ball valve and spectacle blind and also location of spec break.please help me whether in-situ testing for check valves against leakage is required.