Foaming oil in Seperator

[horseysi]

Hi,

I have a problem with foaming in the oil separator of a Sabroe 128 compressor.

I have checked SH on all ten frozen cold-rooms, and set up these rooms so I am aware that I have zero flood back from them.
There is also a galley set up on the same compressor line, hosting ten or so frozen uprights.

I cannot see any flood-back evidence on the suction line, and am running with a Total SH at compressor of around 30*C.

The system is seawater cooled, and that also includes the oil cooler. The seawater at the present is around 30*C.

Do you think the oil may be contaminated? Or can you think of anything that I may be overlooking? Prior to my recent works the liquid receiver was left (intensionally) empty. It has been suggested to me that this may be the reason why! I have not heard of this tactic, however I am open to suggestions. I have also thought of agitation, and liquid cooling for the oil, however the oil is seawater cooled, and there is nothing in the separator to agitate!
I am not really in a position to simply 'replace' this oil as I am in the middle of the ocean!

I look forward to replies from industrial, experienced Ref engineers. I have checked all the obvious liquid flooding possibilities and welcome some experience to give me some more ideas. No offence meant to some.

I can answer questions should you have any..

Cheers,

Si

[RANGER1]

horseysi,
can you give us
refrigerant type
discharge pressure
discharge temperature
oil temperature.
suction pressure
suction temperature

Do you have any liquid line/suction line heat exchanges or economizers?

[Magoo]

As per the questions from Ranger1.
But an over filled oil separator will give the symptoms that you describe, high velocity through an over filled separator will give effect of foaming. If so drain oil from system to the design separator level, too much oil will increase gas velocities and entrainment and agitation/ foaming effect. Check sab manual for maximum oil level in separator. Cold oil will give similar reaction.

[horseysi]

horseysi,
can you give us
refrigerant type
discharge pressure
discharge temperature
oil temperature.
suction pressure
suction temperature

Do you have any liquid line/suction line heat exchanges or economizers?
Hi,

R507
Discharge pressure: 16BARg
59.4*C Discharge Temp
24*C Discharge S/H
48*C Oil Temp
0.7 BARg suction Pressure (so to achieve 0.9 Bar in the evaporators)
0.5*C Suction Temperature.

No liquid line/ suction line heat exchangers and no economizer. Oil cooler is cooled using 'fresh water' which is approx 29*C, and there is no liquid injection to cool the oil further.
The issue has been here since I put the 'new' oil in place. I am sure it is a dodgy batch, so I am going to send some for analysis, but first I want to eliminate the possibility of human error on my part.
Incidently I have no issues with oil pressure ar temp. And the unit seems to be running faultlessly, however I have seen the results of oil staration before and it takes a lot of work to make it right!

Let me know if you can think of anything, as I am surely in panic mode here, and feel I could be missing something!

Cheers,

[horseysi]

I filled the separator to the mid point of the sight glass as per Sabroe recommendations. The level has gone down (as seen when I switch the compressor off) so I know that the oil is foaming into the discharge line and being pushed to the evaporators!
I have also tested the sump heater, which incidently is on all times, and there is no issue there. I allowed the oil to heat for 24hrs to reach 37*C temp prior to starting the unit.

Thanks for the interest. I appreciate your input. Keep thinking, it's a tough one, this one!

Si

[RANGER1]

Good point from Magoo about oil level to high.

Nothing obvious with the readings given.

If you turn compressor off, does oil look clear?
If you take an oil sample, does it look like new oil?

If you change oil again at suitable time, maybe be cautious with water cooled oil cooler, as it would be good
practice to isolate & drain water out of it if depressurizing package & or connecting vacuum pump.
If oil cooler does have a leak it can prevent disaster, or reduce the consequences of it.
Maybe pressure test could be part of preventative maintenance when checking oil cooler & condenser.

My questions are if there was a possibility of sea water entering oil charge if the high oil level is not the issue.
Did you replace oil with same type of oil exactly?

[horseysi]

Hi,

Oil looks clear on stop and the sample shows no signs of fault.
I did drain the cooler when I changed the oil. The reason to replace the oil was the oil came back from analysis with bad reports. I had to replace the full charge of oil for new, including filters.
I pulled avacuum on the compressor/oil reciever prior to refilling, and used that vacuum to pull the oil into the system. I then ran the oil pump to ensure that this went throughout the compressor and back to the reciever.
I ASKED for the same. Same brand: Emkarate, same product: RL100H, however, and I do not mean to be offensive to any readers, sometimes you don't know WHAT you're getting when you order from a shore-side vendor.
There is no seawater on this system. It is fresh water cooled, and I have no charge loss at all.
I also have no room temp issues, and no abnormal sounds from the compressor. I have ordered a complete restock for the oil, but this will not arrive from Europe for three months!

I hope this helps..

[pcvh1976]

For provision plants it is better you use oil with viscosity 32. with 100 the oil is pissing trough the system. probably system is overcharged with oil.And did you checked if the oil return line is working? (simple rules in marine refrigeration Low pressure plants 32 and High pressure 68 viscosity). If the oil-separator is full what is the level in the compressor? keep the discharge press/temp at 17.5Bar/40C.

[horseysi]

For provision plants it is better you use oil with viscosity 32. with 100 the oil is pissing trough the system. probably system is overcharged with oil.And did you checked if the oil return line is working? (simple rules in marine refrigeration Low pressure plants 32 and High pressure 68 viscosity). If the oil-separator is full what is the level in the compressor? keep the discharge press/temp at 17.5Bar/40C.


There is no Oil return line on a Sabroe 128. The oil leaves the compressor, and is separated in the separator, then is pumped to the compressor via suction/discharge diff.
The system is not overcharged with oil or refrigerant.
The RL100H is specified in the compressor docs, so I tend to think that is the way to go, in case of fail I cannot be held responsible.
To make things worse, I have been informed by Emkarate that there is counterfeit oil being supplied in China. It looks like the oil recieved, and subsequently installed, may be MINERALoil. This would explain the foaming, when the R507 is breaking up. I will need to quick smart replace the current oil with original RL100H, so if anybody knows where I can get 80 Ltrs of this in Cambodia, I will be happy!!!!

Si

[cricri]

Hi Horseysi,

what do you mean with 0.5*C Suction Temperature.
is it the temperature or the delta / LP sat?

[Magoo]

Try CPI out of Singapore.

[mbc]

Just for your information

here we have a lots of oil comes from china with same name but with different prices and quality .

check your oil .
your reports says it is from your oil type .

when it happen? is it in start time or running time ? or when you change the load ?