Offshore criteria for Plant air and IA receiver's sizing 1

[Sawsan311]

Dear All,

I need your feedback regarding any specific offshore criteria available in good design practice which tends to request the designed to consider less buffer time for sizing the utilities vessels (IA, PA and N2 receiver vessels) on offshore Jetty platforms. Would there be any structural limitation in restricting the designed from following the standard onshore 15-20 minutes time typically considered for sizing similar systems.

Thanks

Regards,

 

[MJCronin]

You state:

A "specific offshore criteria available in good design practice" for air/nitrogen receivers ?

I do not understand your convoluted question and I do not understand why sizing a compressed gas receiver would be any different for an onshore or offshore or on-ship or any other system.

It all comes down to the engineer's judgement about how often he wants to start the compressor. The engineer must consider the volumetric capacity of the both the receiver and the compressed gas piping system. We have no idea about your piping system layout.

Remember the purpose of the receiver: ..... A compressed gas receiver is used to store high-pressure gas from the compressor. Its volume reduces pressure fluctuations arising from changes in load and from compressor switching. A secondary purpose is to provide a central location to collect condensate from the gas.

Many compressed gas systems will run just fine without a receiver....... (However, your compressors will wear out much sooner from constant cycling)

"Would there be any structural limitation in restricting the designed from following the standard onshore 15-20 minutes time typically considered for sizing similar systems"

I don't understand this and I don't know what to say ....

What are you referring to ?... Specifically, which codes and standards govern the design of your systems? ... You have given us no details

Have you ever designed/specified a compressed air system before ?

This might help

https://www.airbestpractices.com/sites/default/files/Calculating Storage for Demand Events.pdf

No details = Poor answers

MJCronin
Sr. Process Engineer

 

[Sawsan311]

Dear MJCronin, I have designed more than 33 onshore plants having IA and plant air systems, hence you should have no doubts on that.

I am equally questioning whether such systems in offshore Jetty installation would have different design criteria. The reason I am asking is that in fact I expressed there should be no differences in hold-up time and buffer requirements to accommodate IA shutdown and fluctuations in air compressor, however one of the colleagues attending the meeting stated there are unique criteria for offshore installations.
If you have no experience in offshore system designs then you may not reply.

Regards,

 

[mk3223]

IMO, the Client may have different requirement for the hold-up and buffer times for the offshore equipment, such as the air receiver volume vs the air header volume, as well as the material of 316LSS, painting, etc. And, your colleague may know the specific criteria from the Client.