Nitrogen PSA Unit & its Compressor Efficiency

Your real problem seems to be an unwillingness to pick up your telephone and use it to talk to the equipment manufacturer.

Filters are blocked.

Purge air is excessive. Increasing flow on compressor without you realising it (other than pressure loss into the PSA unit) thus reducing available output from PSA unit that you do notice.

Well even if filters are blocked which occurs b/w compressor & PSA unit, the pressure at compressor must be high but it's is ~5.6... As I said cycling & loading/unloading algorithm is checked via stopwatch so how come purge air gets higher. I mean if the SOV is faulty & purge duration/frequency is higher only then what you say is true

I can only guess. My personal experience is with desiccant type PSA dryers, but next to none with nitrogen or oxygen generators. But assuming reactivation is carried by passing low pressure compressed ait through the desiccant to drive off the absorbed oxygen, then there has to be a minimum amount of purge.

The amount of purge air has to be provided against a back pressure caused by pipes, valves, the desiccant itself, and outlet filters and silencers, such that if set up with flow meters in working conditions, the removal of a silencer (becoming blocked in use, for instance) could reduce the back pressure so much that it causes excess purge flow - which could exceed the compressor output thus explaining the drop in pressure at the compressor, which then reduces the pressure available to the air through the PSA unit and hence the output to the plant.

But as I said, just a guess.

The answer is maybe. Maybe you need to go through this PSA unit with a stonger intention of finding the rest of the problems. If the inter-cooler is leaking, what is leaking? Is it an air leak? You did not specify. You need to restore the intercooler anyway, replace filter when back-pressured, not on schedule.

Your next telephone call should be to the vendor. Get an interpretor if you already know you do not speak the vendor's native language. Be prepared to actually spend some money to fix the problem, it will not go away by itself.

If the cooling water pressure is ~2.5bar in the shell & the air pressure in tubes is ~6bar of coarse air will leak out of system, that is is observable at the cooling water outlet point which will appear gushing...

We have solved our problem by rectifying leakages in our N2 distribution system, however, what about this claim to judge compressor health "compressor is reaching 7.4bar within 93sec"

The statement of deadheaded pressurization of 7.4 bar within 93 sec tells you that the compressor can produce pressure. This says absolutely zero about its capacity of flow at pressure.

Is it possible your PSA unit is showing higher pressure due to temperature cycling?

Some of the information does not make sense to me, since you were mentioning over-pressure, but also stating that you had low flow output. Leakage of product is an obvious problem, glad that you got that attended to. Does this mean the system is now performing at the overall specified level?

Think of your compressor circuit in a way not unlike an electrical circuit. Blocked-in pressure is analogous to open-circuit voltage, and 100% flow without back-pressure is analogous to short-circuit current, this allows a calculation of "source resistance".

Surely the compressor curve has something resembling this in the charts. Contact the equipment vendor if insufficient information on site.