PURPOSE The purpose of this study is to determine whether Griflube Bio-Syn EHC Fluid can be successfully used to replace Phosphate Ester fluid in existing hydraulic fluid systems of electric utility steam turbines.

BACKGROUND Since the late 1960’s most electric utility steam turbine hydraulic fluid systems have incorporated high pressure hydraulics to control the critical components of the turbine’s control and protective systems.

The change from low pressure to high pressure hydraulic systems significantly reduced the size of the hydraulic actuators used to position the steam valves. In addition the response time of the valves improved greatly, making overall operation more reliable.

The pressure requirements of these systems were increased from approximately 200 PSIG (13.8 BAR) to greater than 1600 PSIG (110.3 BAR). This created the potential for catastrophic fires in the event of a hydraulic fluid leak in the area of hot steam pipes. As a result of this dangerous situation Fire Resistant Fluids (FRF) were introduced for use in these systems.

In a majority of the applications the Fire Resistant Fluid (FRF) currently in use is a “phosphate ester” fluid. This fluid provides excellent hydraulic capabilities; while at the same time has good fire resistant characteristics.

For more than 40 years these systems have provided safe and reliable operation, but over the past 5-7 years the high pressure fluid systems have seen a significant increase in problems. In most cases these problems have not caused forced outages, but the trend is an increasing severity and number of problems within these systems.

The majority of the problems identified in systems using phosphate ester fluids were directly related to the fluid and the media used to control the chemistry of the operating fluid.

In addition to a significant increase in operating and maintenance problems caused by the phosphate ester fluid, the handling and disposal of the fluid is becoming a major problem due to the increased emphasis on personnel safety and environment issues.

Approximately ten (10) years ago Hill and Griffith Company developed a replacement hydraulic fluid for the steel casting industry which also uses phosphate ester fluid in their hydraulic fluid systems.

PROCEDURE
COMPATIBILITY WITH PHOSPHATE ESTER FLUID STUDY
1. Using a hydraulic fluid system simulator mix 50% used phosphate ester fluid with 50% new Griflube Bio-Syn EHC fluid in the clean reservoir.
2. Install a new 3 micron beta 200 pump discharge filter and 10 micron beta 200 return line filter in simulator.
3. Remove the side stream filters (acid control and particulate control)
4. Connect cooling water to simulator heat exchanger.
5. Start pump and circulate fluid
6. Adjust heat exchanger to maintain fluid at 150oF temperature as measured with a thermometer immersed in reservoir.
7. Visually observe interaction of fluid in reservoir through lexan reservoir end cover.
8. Take daily fluid samples throughout the testing and perform the following analysis on the samples ( TAN, H2O)
9. Allow fluid temperature to reach 205oF and hold there for 5 minutes.
10. Readjust fluid temperature back to 150oF.
11. Repeat steps 9 and 10 two more times over a period of 84 hours.
12. Add approximately 1500 ppm of water to reservoir.
13. Visually observe interaction of fluid in reservoir through lexan reservoir end cover.
14. Shut down system
15. Drain and discard the fluid.
16. Observe the inside of the reservoir for traces of residue.
17. Remove the pump discharge filter and visually observe the filter element
18. Backwash the pump discharge filter and analyze the results (Test Method Used)
19. Remove the Return Line Filter and visually observe the filter elements\
20. Backwash the Return Line Filter and analyze the results (Test Method Used)
21. Thoroughly clean in the inside of the simulator reservoir with lint free rags and mineral spirits.
22. Fill simulator with new Griflube Bio-Syn EHC Fluid.

PURE GRIFLUBE BIO-SYN EHC FLUID TESTING OUTSIDE OF SIMULATOR STUDY
1. Using new Griflube Bio-Syn EHC Fluid perform a foam test on the fluid per spec (Test Method Used )
2. Using new Griflube Bio-Syn EHC Fluid add 2000ppm of water as determined by (Test Method Used )
3. Install Synthetic Startch (water removal filter) and circulate fluid through filter.
4. Visually observe the condition of fluid prior to adding water to the fluid and various times during the filtering process.
5. Measure the amount of water in the fluid verses time to determine how quickly and how much water was removed from fluid (Test Method Used )

PURE GRIFLUBE BIO-SYN EHC FLUID TESTING USING SIMULATOR STUDY
1. Run the simulator pump at maximum flow (5 gpm)
2. Control fluid temperature at 130oF
3. Take monthly fluid samples from reservoir and analyze them for TAN, H2O, and temperature(Test methods used)
4. Continue testing for thirteen (13) months.
5. If needed, as indicated by differential pressure alarms change out discharge filter and/or return line filter.
6. Analyze the filters removed above for type of particulate (Test methods used)
7. Shut down system.
8. Drain the reservoir and visually observe the residue inside the reservoir.
9. Take residue samples and analyze the material collected (Test methods used)
10. Thoroughly clean simulator reservoir.

Apparatus

Barry Sibul & Company High Pressure Fluid System Simulator manufactured by Hydra-Power Systems.

Oil Analysis Laboratories test facilities

Results

COMPATIBILITY WITH PHOSPHATE ESTER FLUID STUDY
This test results showed no real problems. Initial reservoir filling showed some foaming, about ¼ inch on the top of the fluid but that dissipated after the fluid reached 110oF.

1500 ppm of water was added to the system. Moisture vapor started condensing on the Lexan cover almost immediately. Within 3 hours it was all but gone.

There was no indication of either the 3 micron pump discharge filter or the 10 micron return line filter being plugged.

The both the pump discharge filter and the return line filter elements were analyzed (Test methods used) with only a minimal amount of residue found with no indication of any additive interaction or fallout noted (Test methods used)

Visual observation of the fluid clarity was noted to be unchanged throughout the test.

PURE GRIFLUBE BIO-SYN EHC FLUID TESTING OUTSIDE OF SIMULATOR STUDY

The foam test performed on the pure Griflube Bio-Syn EHC Fluid (Test methods used)
failed to pass. Hill and Griffith was notified of this condition and after further refining of the new fluid, it passed the test. All new Griflube Bio-Syn EHC Fluid is being shipped to these new refining criteria (What criteria is this)

Hill and Griffith states that they would prefer their Griflube Bio-Syn EHC Fluid be maintained less than 500ppm of water. The water test performed on new Griflube Bio-Syn EHC fluid indicated with 1902 ppm of water in the fluid, the fluid became milky and had gel like substances in it. After a single pass of fluid though the Synthetic Starch Filter (approximately 1 minute), the water content had been reduced to 970 ppm. The gels had dissipated and the fluid had returned to its original clarity. The water removal filtering continued for another 20 hours at that time the water content of the fluid had been reduced to 514ppm. Since Hill and Griffith requires their fluid to be less than 500ppm, a new Synthetic Starch filter was installed. The fluid was filtered for another 48 hours and a final fluid sample indicated the water content to be stable at 312ppm.

PURE GRIFLUBE BIO-SYN EHC FLUID TESTING USING SIMULATOR STUDY

After fourteen (13) months of running the fluid continuously in the simulator there were no significant performance issue noted with the Griflube Bio-Syn EHC Fluid.

Without having to change the Synthetic Starch water removal filter, the water levels in the fluid were maintained between 360ppm and 405ppm.

The TAN was maintained (without the use of any type of acid control filter) between 0.52 and 0.54. It should be noted the normal TAN for this fluid is less than 1.0.

RESISTIVITY CHECKS OF BIO-SYN EHC FLUID

New Bio-Syn EHC Fluid was tested using the HL-1152A-1.2 method to determine its electrical resistivity. It was found to be at 58.82 G-ohm-cm.

In actual running conditions on Electric Utility Stations that a using Bio-Syn EHC Fluid the resistivity of the fluid was found to be greater than 100 G-ohms-cm on all units in all tests. In some cases the resistivity was measured as high as 333 G-ohm-cm.