What Routine EHC Fluid Testing Fails to Detect
Improved EHC Fluid Maintenance through Non-routine Testing
Despite the critical nature of electro-hydraulic control (EHC) systems, many steam turbine operators’ EHC fluid testing programs fail to detect fine insoluble contaminants that are responsible for costly downtime and failures. With minor modifications, however, gas turbine oil tests can be made suitable for use in steam turbine EHC applications. A modified version of the industry-standard membrane patch colorimetry (MPC) test, in particular, allows for the identification of “hidden” contaminants that are often responsible for costly EHC failures.
By exploiting MPC analysis to its full potential, this method can be used to qualify application-specific problems like varnishing and dieseling in addition to quantifying their severity. Once these previously “hidden” problems have been identified, effective EHC fluid maintenance practices can be developed so that steam turbine performance and reliability may be ensured.
Presenter Background: Matthew G. Hobbs is the Senior Chemist at EPT Clean Oil, where he manages research, development and the Fluid Technical Center services. As a technical expert, Matthew works with users to provide lubricant contamination solutions in critical industrial applications. Before joining EPT Clean Oil, Matthew obtained his PhD in synthetic chemistry from the University of Calgary and was the General Manager of a National oil analysis laboratory.
Matthew is also an active contributor to ASTM, recognized recently with the Award of Appreciation from ASTM International. This award recognizes the tremendous contributions Matthew has made to the Petroleum Products, Liquid Fuels, and Lubricants Committee. Of note, Matthew was a vital contributor to the updates of the following ASTM Standards:
- ASTM D4378-20: Standard Practice for In-Service Monitoring of Mineral Turbine Oils for Steam, Gas, and Combined Cycle Turbines
- ASTM D8323-21: Standard Guide for Management of In-Service Phosphate Ester-based Fluids for Steam Turbine Electro-Hydraulic Control (EHC) Systems.