Recip machine - Unloader valve actuation

[planck121]

Hello everyone,
I was in a recent dicussion with one of the compressor vendors who will be supplying a recip compressor for our plant. The compressor is in 99.9% pure H2 service. The vendor is and the manufacturing of the compressor will be in Europe. But the comrpessor will be operated in North America. The vendor recommends using nitrogen to load/unload the unloader valves. We have been using Instrument air in our plant for actuation of the unloaders. The vendor is quoting ATEX regulations suggesting or prohibiting the use of I/A in such application. Personally, I have not seen such a clause anywhere.

Could someone shed light on this topic. Or point me towards any regulations prohbiting the using of I/A for pure H2 re-cip machines. I have actually seen simliar compressors in europe also use I/A so I am not sure where the requirement of using N2 for safety reasons is coming from.

Would appreciate any help/feedback.

Best regards and a quickly approach merry chrismtas to all here.

 

[JJPellin]

This was discussed in thread1036-343400.

Johnny Pellin

 

[planck121]

Thanks Johnny, did not recollect I had posted it prior. I still however seem to be stuck on a concreate basis to develop the argument. I have not come across any document or regulation otherwise that accepts or rejects the use of I/A on any basis whatsoever. So to me it seems like a subjective decision on part of each vendor. The vendor might perform an evaluation and "feel" that nitrogen is safer than I/A based on thier internal assingment and it would hard for me to argue otherwise.

 

[dcasto]

The question that has to be answered is whether the power gas can leak into the process or is there a way for a leak of H2 near where the power gas is vented. H2 and Air together are not fun. I've had old time operators tell stories of walking into the H2 compressor building at night and seeing a blue flame coming from a flange that wasn't visible in the day. One even said he didn't see a flame until his glove caught fire when checking a unit in the day time.

 

[bicycledisciple]

Did you check the API 11P or 618 on stipulations regarding nitrogen use?

Ron
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