High iron content in Oil

[Amjad123]

Hi,
I wanted to get some insights with what might be the reason for high iron content in lubricating oil for ammonia systems. To lay it out straight the iron content is a repitative issue even though after changing the oil, oil filters and fine filter. The upper limit of Iron content is supposed to be 12 ppm, but it is coming to 35 ppm.
Details are as follows;
Compressor - Mycom N 2520LLC
Oil separator - OC2545.
Oil cooling - Thermosiphon Oil cooler.
Condensing temp:- +40 degC
Evaporating Temp:- -40 degC.
Oil Temp on higher side : 59 degC.(6 degC higher, may be due to conatmination)

Thanks.

[RANGER1]

Hi,
I wanted to get some insights with what might be the reason for high iron content in lubricating oil for ammonia systems. To lay it out straight the iron content is a repitative issue even though after changing the oil, oil filters and fine filter. The upper limit of Iron content is supposed to be 12 ppm, but it is coming to 35 ppm.
Details are as follows;
Compressor - Mycom N 2520LLC
Oil separator - OC2545.
Oil cooling - Thermosiphon Oil cooler.
Condensing temp:- +40 degC
Evaporating Temp:- -40 degC.
Oil Temp on higher side : 59 degC.(6 degC higher, may be due to conatmination)

Thanks.

Amjad123.
Thanks for joining in.

We have a similar issue with a plant we look after, which is well maintained.
Some of the compressor packages okay, some a bit high, working on same maximum limit as yourself for iron content.
We overhaul compressor, no wear at all in our case.

So 12ppm iron pretty low, achievable, but not in all cases.
See link with a lot of good information.
Johnson Controls/Sabroe suggest up to 100 ppm maximum iron content, discard oil, find cause.

Most important is trend of sample, steady, similar results mean nothing getting worse (hopefully).
Cleanliness of oil, particle size.
Regular servicing of filters, or trending pressure drop.

Regular service of compressor, in your case 25 to 30,000 hrs maximum on compound compressor under those conditions.
That can also determine any wear issues & help understand oil results.

From link it suggests package internally could be rusty, which not much you can do.
Sometimes even opening package to atmosphere for servicing can cause this.
Slide valve, oil pump etc

Your oil temperature is above maximum for Mycom, which is 55 deg C

Microsoft PowerPoint - Oil Analysis Tables (rsareliability.com)

Master_1_ramme (sabroe.com) see page 14

[seanf]

Is the oil thats lost out into the system drained to waste or reused/recovered?

[Grizzly]

Hi Sean. In my experience its been much more common for oil to be recovered and treated as Waste. Especially with Ammonia plant and the Mineral Oils that were Prevalent. Especially since the demise of clavus oil etc. My question is what oil are you using in your ammonia system.
The old addage you get what you pay for still applies I looked after a plant that when first installed, it was recommended to change compressor oil every 3000 hrs. however that Oil was changed to a modern synthetic which was good for 20,000 hrs running.
To give a simple Best practice answer the oil is drained and discarded.
Regards grizzly
PS. Is it just the Oil analysis re the Iron content that concerns you coz as Ranger suggests you seem to be everything correctly and as long as the Oil Pressure diffs and operating parameters are not an issue. The Iron content can be further investigated without to much stress. You wouldnt be using reflo oil by any chance?

[Amjad123]

Amjad123.
Thanks for joining in.

We have a similar issue with a plant we look after, which is well maintained.
Some of the compressor packages okay, some a bit high, working on same maximum limit as yourself for iron content.
We overhaul compressor, no wear at all in our case.

So 12ppm iron pretty low, achievable, but not in all cases.
See link with a lot of good information.
Johnson Controls/Sabroe suggest up to 100 ppm maximum iron content, discard oil, find cause.

Most important is trend of sample, steady, similar results mean nothing getting worse (hopefully).
Cleanliness of oil, particle size.
Regular servicing of filters, or trending pressure drop.

Regular service of compressor, in your case 25 to 30,000 hrs maximum on compound compressor under those conditions.
That can also determine any wear issues & help understand oil results.

From link it suggests package internally could be rusty, which not much you can do.
Sometimes even opening package to atmosphere for servicing can cause this.
Slide valve, oil pump etc

Your oil temperature is above maximum for Mycom, which is 55 deg C

Microsoft PowerPoint - Oil Analysis Tables (rsareliability.com)

Master_1_ramme (sabroe.com) see page 14

Hi Ranger1 ,
Thanks for the info. As you rightly said, the 12 ppm figure is high stakes but we were maintaining upto 15 ppm iron content in our oil since 9 years. So, this sudden increase is worrying us. I am thinking of the oil separator upper side might be getting rusty.
We are using Mobil Gargoyle Artic 300 oil. Oil temp is high and we are investigating it.
Can you please resend the link for oil analysis table as it is not opening.
Thanks for your support.

Regards,

[RANGER1]

Amjad123,
Link seems okay, not sure how to change access unless personal email.
Assume oil sample point the same & drain generous amount before taking sample.
Take another oil sample to back it up.
Have any modifications been made to system, or open to atmosphere prior to higher iron ppm?

Check your email.