9-steps for Steam Turbine commissioning


1. What do you mean by Turbine commissioning?

Turbine commissioning is the process of start-up of newly installed Turbine auxiliaries & Turbine up to satisfactory level.

2. When and how do one shall conduct commissioning of Turbine?

Turbine & their auxiliaries are commissioned after proper install, checking & trials. And it is commissioned under the guidance of OEM (Original Equipment Manufacturer)

3. Write down the sequential steps involved in Turbine commissioning

  • Steam blowing
  • Oil flushing
  • Cooling water system commissioning
  • Evacuation or vacuum pulling system commissioning
  • Condensate lines flushing
  • Calibration of servomotor, interlocks checking
  • Turbine rolling
  • Over speed trip setting
  • Synchronization & loading

4. Write down the various steps involved in steam blowing

  • Hope Boiler is commissioned
  • Steam blowing line is installed properly with required supports
  • Start to increase Boiler pressure up to 40% of operating or 40 kg/cm2 whichever is lower
  • Heat up the line by opening Boiler Main bypass valve, heat up is done at steam temperature around 400 deg C
  • Blow the steam line from steam pressure 40 kg/cm2 to 25-20 kg/cm2
  • Again steam line is cooled up to 100-150 deg C or 3 hours if main steam line from Boiler to Turbine is insulated & 1 hour if line is uninsulated
  • Continue this process for around 20-30 blows
  • Then put the target plate aluminium or steel & continue the blow
  • Blowing is continued till

For Target Plate Made of Aluminum:

The piping considered clean if there are not more than 3 (Three) pitting of 0.5 mm to 1mm dia. in center area of 25 mm X 25 mm and shall not have any deformed edges. Besides this there shall be no pitting in the rim zone. Pitting below 0.5 mm may be ignored.

 For Target Plate Made of Stainless Steel:

The piping is considered clean if there are not more than five pitting of 0.1 mm dia to 0.5 mm dia. in centre area of 50 mm X 50 mm & shall not have any deformed edges. Pitting below 0.1 mm may be ignored

Then normalize the steam line

Connect main steam line flange to ESV (Ensure MS line flange & ESV flange’s prallelity is done)

What do you mean by Turbine supervisory system???

5. Write down the sequential steps for Steam line charging.

 Following steps shall be followed during steam line charging:

  •  Ensure all the maintenance works related to steam lines are finished.
  •  Ensure the clearance from process or Turbine side for charging the steam line.
  • Ensure all the drain and trap valves are opened. 
  • Slowly open the steam line bypass valve and allow for heat up of line.
  • After ensuring line proper heat up, cracks open the main valve and allow for condensate drain.
  • After ensuring no condensate in drain line, open the main valve gradually and observe the hammering. (If hammering occurs suddenly close the main valve). 
  • After opening the valve 100%, wait till line stabilization. 
  • After ensuring no condensate in drain lines, close all the drain valves

6. What is the significance of steam blowing?

Steam blowing allows power station boilers and pipelines to ensure that during normal operation no adhering material in the super heaters, reheaters, and steam pipelines will become dislodged, reach the turbine blades, and damage them. The steam blowing operation cleans all the debris in the super heater, reheater and the steam pipe line connecting the turbine.

7. What are the sequential steps involved in Turbine oil flushing?

Following are the steps

  • Ensure OEM recommended oil is being selected for oil flushing
  • Oil tank is filled with oil
  • Flushing loops are prepared as per OEM recommendations
  • Ensure return oil line is fitted with OEM recommended strainers
  • Ensure oil centrifuge is in place & ready for operation
  • Flush oil by starting lube oil pump & ensure oil is circulating through cooler
  • Keep oil centrifuge ON with heater ON
  • Maintain oil temperature up to 70 deg C for 4-5 hours
  • Charge oil cooler & bring down the oil temperature up to 35-40 deg C
  • Then hammer the oil lines to dislodge the sludge, bur or any other foreign materials
  • Continue oil flushing till return line strainer is clean by 24 microns filter
  • Oil flushing shall be deemed as completed, If Lube oil filter does not choke for more than 24 hours

8-What are the steps involved in cooling water system commissioning?

Following activities are involved in cooling water system commissioning

  • Ensure all erection activities are completed on cooling water system
  • Ensure all instruments are fitted on CW system
  • Ensure cooling tower level is filled with required quality water
  • Check the Cooling water pumps physical condition, if found ok take no load trial Or Ensure CW pumps are commissioned under the guidance of OEM
  • Connect cooling water line with flushing line & leave to open areas (DO not connect return cooling water line to cooling tower)
  • Then start the cooling water pumps & flush all the lines
  • This activity shall be done -5 times & keep on making up cooling tower level every time

9-List down the sequential steps involved in condensate line flushing

  • Condensate system consists of Condenser, CEP, Ejector, GSC
  • Ensure all condensate system is ready for flushing
  • Condensate line should be left open at deaerator floor
  • Ensure hot well level is normal & provision is made to make up the level of hot well
  • Ensure CEP is ready to start or CEP is commissioned under the guidance of OEM
  • Then start CEP & flush the line
  • This activity shall be dine for 8-10 times & every time up hot well level

10-What are the sequential steps for turbine rolling?

  • Ensure Lube oil system is commissioned & is in service
  • Ensure cooling water system is commissioned & is being charged
  • Ensure condensate system is in service
  • Ensure main steam line is charged as per standard process
  • Vacuum pulling is done
  • Reset turbine protections
  • ESV opens & Turbine rolling is done s per OEM guidance


 Questions & Answers on steam blowing






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