Ammonia Compressor Failure

CEKM

GA

Thank for the information given. It really help full.

Need to look at the damaged surface to understand the mechanism and thereby determine the cause.

If there is a lot of smearing on the shaft surface then ammonia is a likely culprit.

Harish

Is this compressor found any crack?

Over period of operation compressor body got crack. if such thing happened then it is necessary to change crank case body.

We found that the compressor crankcase section is still in good condition but only the connecting rod, piston and the bearing damage. Both of them are the same symptom

For many years we used ammonia compressors at ICI and the problem you describe can be resolved by installing compressor crank heaters thus vaporising any ammonia carried by the oil in the compressor. Visible 'frosting' on the compressor heads is not unusual especially at start-up until the ammonia can 'escape' back into the system.Regular oil checks are recommended to check no degregation is taking place.

Visible frosting at the Cyl heads on a low temp machine is common, however the suction side of the compressor is open to the crankcase for pressure equalization, and cooling.

Frosting of cyl heads on start up can be due to liquid carryover, and should be avoided best solution is suction accumulator as described in other replies.

Suction accumulator also will separate any moisture from system, as the moisture will be separated from the ammonia when the liquid vaporizes, moisture will accumulate in bottom of accumulator, and be drained off with oil.

Test I have used to determine if frosting is due to liquid or cold vapor (In any refrigeration system) is the "Hands On" test, if the frost melts when touching the frosted part, cold vapor is present, if frost doesn't melt, likely liquid is present (Hint: Don't do with wet hand!).

Regards CEKM

You may also consider installing a suction accumulator upstream of the compressor. This will prevent slugs of liquid from coming into the crankcase while the unit is running. Liquid refrigerant entering the cylinder will cause extreme stress and can result in damaged valve, broken connecting rods and piston damage, etc.

Hi,

Ammonia highly reacts with brass and/or alloys with brass.

BR,

SAM

All

It's not the anhydrous ammonia itself that reacts with the alloys, it's the ammonium hydroxide formed when the ammonia adsorbs moisture, as stated previously ammonia is highly hygroscopic and adsorbs copious amounts of moisture forming ammonium hydroxide that is extremely alkaline, and does react with the zinc and tin in copper alloys, (The copper also to a lessor degree), iron and lessor reactive metals/ materials are used in any system components that may come in contact with liquid or vapor ammonia.

I have operated several ammonia plants, mostly shipboard, and do like ammonia as a refrigerant. the conservationists should like and promote ammonia as a refrigerant, high latent heat, conserves energy, no halogens to deplete ozone layer, neutralizes acid (As in rain), is a good fertilizer (Used extensively in agriculture, and is "Organic" a good conservationist's buzz word.

Regards CEKM