Ammonia consumption

[manmohan]

Hi friends my plant is need refrigerant charge after few months without any likege it is normal ???

[chemi-cool]

No,
There is a leak, you just didn't find it yet.:D

[Len Fiddler]

The last time I heard this an engineer was bleeding it off into water and selling it as a household cleaner!

[RANGER1]

Hi friends my plant is need refrigerant charge after few months without any likege it is normal ???

If you are sure no leakage it could be in a few places like condenser or in vessel on low side of system due to a solenoid leaking internally, suction trap has level it did not have before?
Anyway, just guessing as we no nothing about your plant.

[josef]

We know RANGER1, he does not have ammonia.

[NH3LVR]

Not usually a big problem with NH3 systems. I have solved may disappearing refrigerant issues by installing rupture discs under the relief valves. Thae tend to leak a little, then stop when the pressure falls, then start again when the pressure rises.

[Grizzly]

Not usually a big problem with NH3 systems. I have solved may disappearing refrigerant issues by installing rupture discs under the relief valves. Thae tend to leak a little, then stop when the pressure falls, then start again when the pressure rises.

A valid point based on Practical experience.

Nice one!
NH3LVR.

[RANGER1]

We know RANGER1, he does not have ammonia.


Josef,
Not sure what you mean, did I miss something?

[Josip]

I believe NH3LVR is right ... also familiar to me ...

safety valve discharge pipe usually venting refrigerants above roof into the air and minor leaks are hardly noticeable (old design school without ammonia sensor at the end of venting pipe)

couple of months is quite a long time if system is relatively small and leak/s relatively big ...

and safety valves check is usually once per year ...


Just my opinion ...

Best regards, Josip :)

[RANGER1]

I believe NH3LVR is right ... also familiar to me ...

safety valve discharge pipe usually venting refrigerants above roof into the air and minor leaks are hardly noticeable (old design school without ammonia sensor at the end of venting pipe)

couple of months is quite a long time if system is relatively small and leak/s relatively big ...

and safety valves check is usually once per year ...


Just my opinion ...

Best regards, Josip :)


Josip,
Good to see you back, as has been awhile.
Never heard of this scenario myself as a common thing.
Pressures should never be higher than 10-15% of relief valve setting, that's where compressor trip points should be without exception.
When valves are tested it should be checked for zero leakage at that pressure to check it's security after relief pressure set.
Maybe poor quality reliefs?
Rupture discs are good if multiple reliefs go into common header to see which one let go in event of release that should never happen.
Also good for ***** or synthetic refrigerants to prevent loss of refrigerant.
I also think your old school ammonia sensor on relief vent is best, also oil in "s" trap is good as well.

[Josip]

Hi, RANGER1 ... thanks ...
been busy around house and family ... one son with his family moved into new house (rebuild old one) and there were never ending requests for help since spring time ... another son moved back to our house ... again repairs, improvements, paintings ... 12 hours a day shift ... and still not finished, but winter is coming and some works we have to postpone until next year spring or summer ....



Josip,
Good to see you back, as has been awhile.
Never heard of this scenario myself as a common thing.
Pressures should never be higher than 10-15% of relief valve setting, that's where compressor trip points should be without exception.
When valves are tested it should be checked for zero leakage at that pressure to check it's security after relief pressure set.
Maybe poor quality reliefs?
Rupture discs are good if multiple reliefs go into common header to see which one let go in event of release that should never happen.
Also good for ***** or synthetic refrigerants to prevent loss of refrigerant.
I also think your old school ammonia sensor on relief vent is best, also oil in "s" trap is good as well.


It is not a common thing ... more exception ... can be effect due to lack of good relief valves pressure test .... poor quality reliefs ... for some reason running plant at high discharge pressure ... some reliefs are equipped with handle for manual operation for check and maybe not close tight after check or just be opened by accident during installation without note to supervisor (to retest relief) ... new plant ... maybe young operators without a lot of experience ... etc .. kind of Murphy's law ...

... as I remember happened to me only on two plants (each with only one relief passing, but all were connected to common header going over roof and not quite good for access) so it is not so common but can happen ...

Best regards, Josip