Pre commissioning steam turbines load trial

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Steam turbines

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  • hello dear nagesh, would you please send me this doucment. it is very good. i am rotating isnpector in iran.my email : m_abdi83@yahoo.com
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  • hi bharath,

    There is no calculation as such , This is the standards set by companies based on there past experiences
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  • Mr. Nagesh,
    I have got an enquiry for steam blowing of steam tracing pipelines 20' size and 600 meters in length. I would like to know how much ton capacity boiler is required for the job. Is there any formula or excel sheet with you.We have portable boiler of capacity 3 ton and 2 ton-3 Nos. with us. It will great help to me if you can explain or forward to email id bharatjshetty123@gmail.com.
    We have never done steam blowing previously and it is first time with no experience so it grateful of you if you forward the procedure in depth with diagrams.
    looking forward for your reply.
    Thanks in advance.
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Pre commissioning steam turbines load trial

  1. 1. BY: NAGESH H
  2. 2. PRE COMMISSIONING : The activities carried out before passing steam to the turbine is called pre commissioning. COMMISSIONING: The activities carried out to ensure turbine performance is as per design is known as commissioning.
  3. 3. TECHNICAL DATA SUBBURAJ PAPER PVT LTD
  4. 4. PRE COMMISSIONING STEAM BLOWING CONDENSER TEST BEARING CLEARANCE, FLOAT, DUMP OF ROTOR,GEAR AND PINION THROTTLE VALVE SETTING ALL SAFETY TRIP FUNCTIONING AND RESPONSE OF SEV
  5. 5. STEAM BLOWING The purpose of blowing the steam lines prior to starting up a new unit is to remove any foreign particle remaining in steam inlet pipeline. The principle behind steam blowing is thermal cycling i.e heating of pipe lines by blowing steam & cooling. This will tend to break mill scale / weld slag away from the pipe wall due to difference in co-efficient of thermal expansion.
  6. 6. EQUIPMENTS Temporary piping Temporary piping support Silencer Target plate
  7. 7. PROCEDURE FOR STEAM BLOWING…. 1. Disconnect steam inlet pipe from turbine emergency stop valve 2. Arrange for target plate of mirror finished aluminum of thickness 10 to 12 mm to be fitted at 1 meter away in the temporary blowing line. which is placed in the main steam line by making a fixture 3. During the blowing down process open all the drain lines from boiler to inlet pipe flange 4. Steam blows should be carried out by fully opening the isolating valve. SUPPORTING PLATE STEAM INLET TARGET PLATE
  8. 8. PROCEDURE FOR STEAM BLOWING 5. Bring the boiler press. up to 70 to 80% of working press. & temp., blow down the steam line until press. drops to 20 to 30% of working press./temp. recommended by boiler manufacturer and then allow the line to get cooled(~40°C ) and then hammer the steam pipe line near joints . 6. Repeat this procedure for three times. 7. Now place the target plate in the fixture & blow down the steam line and allow it to cool. 8. This cycle is repeated till we get acceptance value , In each cycle continue hammering and Stamp the cycle no. on the receiving face of the target plate.
  9. 9. Indentation is acceptable when there are no more than 2 dents of 0.2mm in a 50X50 mm section of target plate. ACCEPTANCE CRITERIA
  10. 10. PRECAUTIONS 1. Check that all pipes are supported properly during blow down. 2. Necessary safety precautions must be taken such as fencing of the area and providing ear protection against the inevitable noise generated during blow down process. 3. No one should move around the blowing area
  11. 11. CONDENSER MASS FLUSHING Dummy flange •Objective: To clean the cooling water inlet and outlet pipe lines of condenser from cooling pond to cooling tower. •Procedure: • Place the dummy flanges in cooling water inlet and outlet line of the condenser. •Prepare a temporary pipe line for flushing •Pump the water from cooling pond till water flows out on top of cooling tower and then switch off the pump. •Drain the water . •Repeat this procedure until the water is clean. Dummy flange To cooling tower at 12 m height Chemically treated water from cooling pond 2 to 2.5 kg/sq .cm Drain condenser
  12. 12. CONDENSER TESTS 1.WATER LEAK TEST: •Pipe line is made from DM water pump to condenser shell. •Fill the condenser with DM water up to the bottom of exhaust casing until water leaks from the exhaust thermo well of turbine. •Ensure that all the pipe lines are filled with water which are connected in the vacuum system. •Hold the water up to one hr and observe any leakage from the flange and welded joints. • Ensure that there is no leakage in the system •Drain the water completely from the system after the completion of test EXHAUST STEAM COOLING WATER INLET COOLING WATER OUTLET HOTWELL
  13. 13. CONDENSER TESTS 2. VACUUM DROP TEST •Isolate the turbine from condenser by providing a ms plate of approximate 10 to 15 mm thickness between condenser flange and bellow flange provided at turbine exhaust flange along with turbine . •Fill the condenser hot well to normal level •Start hogger ejector and create vacuum to the designed value of 0.1 ATA and close the hogger ejector •Check the rate of vacuum drop •Drop in vacuum should not exceed 0.01 kg/sq.cm in 30 minutes. EXHAUST STEAM COOLING WATER INLET COOLING WATER OUTLET HOTWELL
  14. 14. •Place the bottom bearing shells and load the rotor on bearings. •Place a lead wire of 0.7mm thick with a coat of grease circumferentially around the top half of the journal. •Place the top half of bearing shell with its bearing cap and tighten it. •Remove the crushed lead wire and measure the thickness of the crushed lead wire which gives the existing bearing diametrical clearance BEARING CLEARENCE DESCRIPTION OBSERVED(mm) REQUIRED(mm) Rotor fore 0.21 0.18-0.23 Rotor after 0.21 0.22-0.26 Pinion fore 0.37 0.37-0.42 Pinion after 0.37 0.37-0.42 Gear fore 0.27 0.25-0.30 Gear after 0.26 0.25-0.30
  15. 15.  Dump check is done to ensure minimum clearance b/w rotor & nozzle chest and diaphragm nozzle.  Place the rotor on journal bearing.  Assemble the top bearing shells into the bottom bearings and place the bearing cap.  Insert the active thrust pad into its position. Description (Dump) Observed Required Rotor 0.72 0.7-0.8 Gear 0.65 0.40-0.75 Dial indicator position
  16. 16.  To check the float of the rotor ,the same procedure has to be followed but the rotor movement is restricted by using non active thrust pad. Description Observed Required Rotor 0.35 0.30-035
  17. 17. THROTTLE VALVE LIFT First valve is adjusted by feeler gauge and other two valves are set by vernier caliper MAX.LIFT
  18. 18. PRESSURE SETTING Control oil pressure 14kg/sq.cm Bearing oil pressure 1.9 kg/sq.cm Accumulator pre-charge pressure 12kg/sq.cm (80% of control oil pressure) Trip circuit oil pressure 1.5 kg/sq.cm
  19. 19. VERIFY ALL INTERLOCKS AND ALARMS
  20. 20. MANUAL TRIP L P TRIP SOLENOID TRIP CHECK ALL SAFETY TRIPS ITEM SETTING VALUE SET VALUE LP TRIP TRIP PR. RESET PR. 0.5-0.8 0.8-1.2 0.8 0.9 SOLENOID TRIP 0.5 0.5 ENSURE THAT SEV AND TV CLOSES IN ALL TRIPPINGOVER SPEED TRIP
  21. 21. VIBRATION PROBE SETTING PROBES HAS TO BE SET FOR 9 to 12VOLTS 1.TURBINE FORE 7.ALTERATOR FORE 2.TURBINE AFTER 8.ALTERNATOR AFTER 3.PINION FORE 9.AXIAL 4.PINION AFTER 5.GEAR FORE 6.GEAR AFTER 9
  22. 22. To check various pressure settings with in the lube oil and control oil system To check vibration level with in limits Governor take over To check the over speed trip and electrical trips are functioning correctly To prove performance of machine and to satisfy customer COMMISSIONING AND LOAD TRIAL OBJECTIVES:
  23. 23. COMMISSIONING PROCEDURE FOR SOLO RUN TEST AND LOAD RUN TEST • Open all drains of steam in turbine •SEV drain •Nozzle chest drain •Wheel case drain •Casing drain •Throttle valve drain •Check oil level in oil tank through oil level gauge and temperature of the oil should be minimum 35deg c • Ensure that cooling water to oil cooler, condenser,GVC is flowing • Start AOP
  24. 24. •Start the motor driven barring gear. An interlock ensures that the baring gear can not be started before bearing oil pressure is established i.e 1.5kg/sq.cm • Run barring gear for a period of 12 hours, if turbine is started first time for an SCG 3 turbine. •Check the vibration level are with in limits •Allow sealing steam for laby packing's
  25. 25. START EJECTOR SYSTEM HOGGER COOLING WATER INLET AND OUTLET MOTIVE STEAM VAPOUR FROM CONDENSER BASIC PRINCIPLE Entrapped gases MOTIVE STEAM
  26. 26. START MOTOR DRIVEN CEP BLO DISCHARGE SUCTION DELIVERY To ejector tubes Suction from hot well Balancing leak off P=6kg/cm sq
  27. 27. • RESET ALL SAFETY TRIPS Solenoid trip Manual trip LP trip MANUAL TRIP L P TRIP SOLENOID TRIP CONTROL OIL LINES DRAIN LINE PUSH TO TRIP PULL TO RESET
  28. 28. •Crack open the steam supply isolating valve and warm up the steam pipe line to turbine SEV •Reasons for warm up : To avoid uneven expansion of pipe line, rotor and casing To avoid water hammering effect •Start GVC blower •Initially lift the HP actuator lever •Gradually open the SEV, which should be sufficient for warming nozzles and casing. •After few minutes, when the turbine warmed through and all water has been expelled, then partially close the turbine drains
  29. 29. TURBINE START UP CURVE TO BE FOLLOWED 1st cs-2600 rpm Sudden jump 2300-2900
  30. 30. • CHECK FOR OVER SPEED TRIP AND SET ELECTRICAL TRIP SET OVER SPEED TRIP WITH IN THE RANGE OF 110-115% OF RATED SPEED 7829rpm TO INCREASE TRIP SPEED Valve Remove material on this opposite face if os trip is less
  31. 31. TURBINE START UP CURVE TO BE FOLLOWED
  32. 32. TURBINE START UP CURVE TO BE FOLLOWED
  33. 33. CHECK FOR VIBRATION LEVELS AND TEMPARATURE
  34. 34. ITEM POSITION READINGS MILS/PP ROTOR FORE BRG X Y 0.8 0.7 ROTOR AFTER BRG X Y 0.73 0.42 PINION FORE BRG X Y 1.75 1.48 PINION AFTER BRG X Y 0.74 0.46 GEAR FORE BRG X Y 0.25 0.27 GEAR AFTER BRG X Y 0.33 0.42 AXIAL X (TOP) Y (BOTTOM) 5.3 4.2 VIBRATION READINGS IN SOLO RUN TEST
  35. 35. LOAD CURVE DURING STABLE OPERATION
  36. 36. ITEM POSITION READINGS MILS/PP ROTOR FORE BRG X Y 0.8 0.64 ROTOR AFTER BRG X Y 0.51 0.4 PINION FORE BRG X Y 1.8 1.5 PINION AFTER BRG X Y 0.68 0.43 GEAR FORE BRG X Y 0.28 0.38 GEAR AFTER BRG X Y 0.37 0.58 AXIAL X Y 5.3 4 DRIVEN MACHINE FORE BRG X Y 0.9 1.63 DRIVEN MACHINE AFTER BRG X Y 0.69 0.55 VIBRATION READINGS WITH LOAD RUN TEST
  37. 37. SPEED RPM 6822 LOAD MW 1.5 STEAM INLET PRESSURE kg/Sq.cm 33.8 436TEMP. °C STEAM FLOW TPH 14.3 WHEEL CASE PR. kg/Sq.cm 4 EXTRACTION PR. kg/Sq.cm 0.75 TEMP °C 203 FLOW TPH 3.3 EXHAUST PRESSURE PRE. kg/Sq.cm -0.83 TEMP °C 84 HOT WELL TEMP °C 45 COOLING WATER INLET PR kg/Sq.cm 1.6 INLET TEMP °C 19 OUT LET PR. kg/Sq.cm 1.3 OUT LET TEMP °C 28 EJECTOR STEAM INLET PR. kg/Sq.cm 10 INLET TEMP °C 330 VACCUM PR. kg/Sq.cm -0.85 OIL PRESSURE LUBE OIL kg/Sq.cm 2.1 CONTROL OIL kg/Sq.cm 14 D.P ACROSS FILTER kg/Sq.cm 0.1 BRG TEMP. °C ROTOR FORE 65.8 AFTER 82.1 PINION FORE 69.1 AFTER 56.6 GEAR FORE 51.2 AFTER 46.2 ALTERNATER DE 65 NDE 67 COOLER OIL TEMP. INLET °C 45 OUT LET °C 32 LOAD TRIAL(PARAMETERS)
  38. 38. COMPARISION OF SPECIFIC STEAM CONSUMPTION OF MACHINE AT SITE WITH RESPECT TO PERFORMANCE CURVE
  39. 39. STEAM CONSUMPTION*CORRECTION FACTORS(A,B,C,D)*AGE FACTOR POWER GENERATION SSC = SSC = Kg/kwh SL NO PARAMETERS PROJECTED VALUES AVERAGE VALUE UNITS A Inlet steam pressure. Kg/sq.Cm B Inlet steam temperature ° C C Exhaust steam pressure Kg/sq.Cm D Turbine speed Rpm E Electrical load Mw ACTUAL STEAM CONSUMPTION F Total power consumption Kwh G Total steam consumption Kg Inlet steam pressure Inlet steam temperature Exhaust steam pressure Turbine speed Age factor Correction factors
  40. 40. STEAM CONSUMPTION*CORRECTION FACTORS(A,B,C,D)*AGE FACTOR POWER GENERATION SSC = ACTUAL SSC = 5.73 kg/kWH at average load of 12.5 mw Sl no parameters Projected values Average value units A Inlet steam pressure. 66 57 Kg/sq.Cm B Inlet steam temperature 490 502 Degc C Exhaust steam pressure 1.54 0.8 Kg/sq.Cm D Turbine speed 7055 6693 Rpm E Electrical load 15 12.5 Mw ACTUAL STEAM CONSUMPTION F Total power consumption 25000 Kwh G Total steam consumption 165000 Kg Inlet steam pressure 0.9 Inlet steam temperature 1.0 Exhaust steam pressure 1.0 Turbine speed 0.965 Age factor 1.0 Correction factors PROJECTED SSC = 6.17 kg/kWH at average load of 12.5 mw Example: FR 1
  41. 41. PROBLEM FACED IN SITE SITE:SUBBURAJ PAPERS •Dump was found 0.37 instead of 0.75 Cause: High points in the nozzle chest seam welding. Corrective action: The seam welding in the nozzle chest was blue matched with the shrouding of moving blade and some high point was found in welding. welding high points were corrected by filing and finally dump was achieved. •CEP was consuming more than rated current Cause: Misalignment of pump and motor

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