+4 votes
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Lesson Learned: Turbine deterioration caused by fuel gas

asked Mar 27, 2014 in Mechanical by sabdullayev (5,290 points)

The hot section of the gas turbine can get damaged by the presence of hydrocarbon liquid in the fuel gas. It will plug nozzles due to explosion and fire during the combustion cycles.

The hydrocarbon liquid can get into the turbine supply line from the gas scrubber through the sources:

  • Pressure and gas flowrate exceed the scrubber capacity
  • Surge in hydrocarbon due to fluctuation in gas pressure
  • Wrong operation of the centrifugal separator
  • Foaming in the pipeline leading to the scrubber
commented Mar 27, 2014 by Normandy (21,000 points)
Thanks for the LL.

2 Answers

+2 votes
answered Apr 13, 2014 by Normandy (21,000 points) | selected Apr 14, 2014 by Normandy
 
Best answer

Some examples of the deterioration to the turbine caused by fuel gas:

  • High temperature in the compression chamber can cause distress to the blades
  • Hydrocarbon liquid in the fuel gas that is not burned can ignite and create failure for the transition piece
  • Back pressure built up can also cause compressor surge

In order to prevent the hydrocarbon liquid in fuel gas, it needs to be treated and have a superheat temperature of at least 500F above the hydrocarbon dew point.

+2 votes
answered Apr 13, 2014 by aodai (1,960 points)

These also are probable causes of turbine deteriorations:

  • Improper alignment can cause higher bearing loads
  • Rotor needs balancing
  • Loss in the compressor or generator
  • Problems in gearbox and coupling
  • Damaged combustor nozzle
  • Bearing wear
  • Component creeping
...