Lithuim Nitrate allowable level??

[gfhelper]

What is the proper level of Lithuim Nitrate in an absorber. I have a McQuay/Sanyo 500 ton Absorber. Approx 5000 lbs of solution. I just had a chemical test done and it came back 3 mg/liter on the test. This is the first time this test was preformed (molibdate/nitrate) check. In the past only done a molibdate test only. I cannot find anything in the book or on the msds for the lithuim bromide as to what the level should be.

[absrbrtek]

Who did the testing? Is it molybdate or nitrate inhibited?

[stickerhead]

Should not be nitrated, only molybdated. 50 -300 ppm of molybdate according to the O&M. 130 - 170 is a good middle number

[gfhelper]

It was tested by rocky reseach out of nevada, It is molybdate.
The Tech is a york man and he says his test always show lithuim nitrate, when they tested ours it came back 0 on one machine and 3 on the other.

And why should it not be nitrated?

Sorry for taking so long in getting back to answer your questions.

[RichardL]

Lithium Nitrate is the original inhibitor used in absorbers from the oldest 16C Carriers to the original Trane "A" models.
It is Very nasty stuff and creates extreme problems as it is depleted by creating some "Very" nasty gasses including Hydrogen.
The older Nitrate inhibited chillers were mostly converted to Lithium Chromate with much better results.
The present date Lithium Molybdate is without a doubt the best inhibitor to date as opposed to the Arsenic or Nitrated inhibitors and has a much higher operating temperature needed for the direct fire or multi-stage absorbers.
It is very possible that a Molybdate inhibited absorber might show some Nitrate in a field test or even a Lab. test. But "Unless" some-one has wrongly added Lithium Nitrate to a Molbdate absorber, I would not concern myself with the analysis report of trace Nitrate in the chiller...Keep the Molybdate in the 150ppm range and maintain a decent purge to expel any affects of the inhibitors and the chiller will keep perculating along...
As the chief engineer of Coca-Cola once told me....
"The only thing I have seen these things absorb....Is money"!!!!
Grumpy old fart he was..........

[absrus]

I think you are confused. Nitrates do not create gasses such as hydrogen. Hydrogen is a by-product of corrosion due to the lack of inhibitors such as nitrates, molybdates, etc. The breakdown of the nitrates causes a by-product of ammonia which is bad for copper tubes.

The idea of any inhibitor is to create a barrier between the carbon steel in the chiller and the bromide solution. Nitrates and molybdates create a barrier called magnatite. This is the black film that forms on the steel surfaces and the stuff that can cause the solution to turn black.

Chromates, on the other hand, is a great inhibitor but good luck disposing of the bromide when the time comes and with EPA and OSHA policies, good luck trying to service it.

As for nitrate inhibitor in molybdate solution, most new bromide charges start with a small amount of nitrate inhibitor in the solution. This is because the molybdates take time to cure and coat the steel surfaces. The nitrates are their to pacify the surfaces early on until the molybdates take over. Generally less then 100 ppm is acceptable. Anything above that can cause the solution to out-gas an orange foggy cloud that will act as a non-condensable and is very hard to stop