We’ve started a simulation, ran it and then determined we needed some field analysis to confirm our data. Our field compressor analysis was performed and we found the discrepancies that were skewing our results from the simulation. Now we can use our field data to fine tune our simulation and start using it for our new reliability tool.
The field data from our compressor analysis indicated a difference in the end clearances for the head end and crank end compared to the tag and logged clearance values. Fine tuning the clearances to the dynamic running clearance measured in the field from the analyzer will bring our simulation to be the most accurate to calculate stage flows and inter stage pressures as well as expected discharge temperatures.
Also found were inter stage pressure drops from the pulsation controls on the unit as well as the cooler. Those pressure drops are important to note for future comparisons and for accurate inter stage pressure calculations. Why is this important? Knowing the expected inter stage pressures is now a sensitive set point for future comparisons for unit health and reliability assessments. Also this will aid in formulating results for tests of other operating conditions for the unit.
With the simulation set for the correct running clearances and pressure drops, we can now input field conditions as they come in from the operations staff for health checks. That’s right, the simulation now can be used as your first health assessment tool for any suspect problems from the field. There are basically three alarm areas that you can now set to find a problem with your unit that would require some inspection and service. Primarily would be flow, where the measured flow from the field doesn’t meet the simulation. When this happens its typically also followed with the second indicator, a discrepancy in pressures on one of the stages, if any. Multistage units are easier to diagnose as you usually have an inter stage pressure that is much higher or lower than the simulated result and points to a problem with flow (health) of the stage. Single stage units of course may not have a similar result. Following that you can now narrow in on the third indicator, temperatures to find the last part of the puzzle. Increased temperatures of any of the stage discharges could indicate a health issue needing further analysis and inspection.
Utilizing a compressor simulation program in different ways can be a very powerful troubleshooting tool when tuned to the actual field conditions. I use simulation programs all the time to verify unit loading and health for clients that have us come out to perform compressor analysis on regular intervals. The simulation is accurately tuned to the real field conditions and now can be used at a moments notice to quickly diagnose health with just field data of pressure and temperature input. Being a reliability resource, you have to be able to use many tools to provide the best health assessment for your clients.
Jason Hoffman C.E.T. from Enhanced Maintenance Solutions Inc.
