water ingress into turbine oil

Water ingress can come from many sources and steam turbines are bad about water in oil just because it is a steam turbine. Filtration systems are used worldwide to remove the water from the oil. Turbine oils are designed to help in the water removal.

In-gress can come from environment; oil coolers that use water, the process steam can even put water in the oil.

We have a couple of steam turbine systems and unless the cooler starts leaking most of our water problem occurs after a downtime and before a startup. IF you do not have a filtration system that removes water that water stays in the oil a long time. Need to filter it out.

Water contamination can happen after downtime as condensation takes place and the water ends up in the oil. It is a good idea to remove the water before start up. Water is never good as it can cause lack of lubrication as it disturbs the oil film and thus causes wear of mechanical systems.

Dear Aidil

Other point of water ingression in Steam Turbines is Seals near bearings.

Sometimes whenthe seals don't work very well, some of steam goes to the bearings, and contaminates the oil.

On the other hand, if you have found metals, I would recommend a complete Flushing of the system (according to ASTM D-6439-05), and it would be a good idea, to installa a Oil Purifier for removing water of the system. This Oil Purifier will help to you in the future for avoiding non Programmed Shutdowns.

Best Regards,
Cristián Schmid.

aidil,

the normal cause of moisture ingression in steam turbine is due to excessive steam leak through the turbine end seals. your plant should have a portable centrifuge/purifier unit to address this issue since this is normal issue for steam turbine. yes, the ultimate solution is to replace the seal. routine moisture analysis should also there so that you will be able to determine the time the reservoir needs centrifuging.

a quick check you can do is to put a loose fabric tied to a stick and head it close to the space between bearing box and turbine end seals. if the movement is significant (better compare it with other healthy turbine), then you can fairly conclude the end seal clearance is off. you may get your operation to increase the opeaning of leak steam return line going to the condensor to reduce the leakage rate.

tripped on thrust may be due to other reason. do not jump to the oil quality first. do cover all angles..if the pump is pumping emulsified oil, the abnormality you will get to see first is the lube oil and control oil filter performance..

Thank you for the brief description of that. I'll look into the ideas that had been sharing from all of you..

Other than that issue, is there anyone had the ideas on turbine additives. How frequent we should do the RULER test to monitor our additives. Some additives maybe related to another additives that will effected when one of them had depleted.

aidil, do you have any historical used oil analysis on your turbines? ASTM D4378 is the industry accepted guide for establishing condition monitoring programs on in-service steam and gas turbines, I suggest reviewing this.

JP Chapin
Fluitec International
j.chapin@fluitec.com

yes..we do have our history data..sampling will be done each 2 months and data will be trend in our database..normally, water content is around 40 ppm and we use caltex regal r&o 32..the problem is we do not find any limit for water content as we want to find the alarm limit for the safe running of the turbine..

quote:

ASTM D4378

Hi, Aidil,
For water content in your sampling point should less than 100ppm

Hi Aidil, there are two concerns with excessive water, damage to machine and damage to lubricant, both are expensive re the reason for low water and as Salu says if you can run below 80-100 ppm that will provide best life for both.
Regards
Rob S

I agree with Don's idea, Recently I came across this,
http://www.fastmr.com/prod/321...er_pumps_global.aspx

You mentioned good point here.It would be nice if you provide some more information about water ingression.

You mentioned good theme here, I am be car about it, and I will pay attention to it.