IN SITU STEAM TURBINE ROTOR STRAIGHTENING POWERGEN EUROPE 4-6 June 2013 Messe Wien, Vienna, Austria

Author names: Enrico Foglino, Ansaldo Energia Energia, Italy Paolo Tolomei, Ansaldo Energia Energia, Italy Elio Tolle, Ansaldo Energia Energia, Italy

IN SITU STEAM TURBINE ROTOR STRAIGHTENING

1.  Rotor bowing causes 2.  Why in situ rotor straightening? 3.  How a bowed rotor may be straightened? 4.  Ansaldo Energia in situ experience 5.  How does it work? 6.  Tools and personnel 7.  Results, time and cost

IN SITU STEAM TURBINE ROTOR STRAIGHTENING

1.  Rotor bowing causes 2.  Why in situ rotor straightening? 3.  How a bowed rotor may be straightened? 4.  Ansaldo Energia in situ experience 5.  How does it work? 6.  Tools and personnel 7.  Results, time and cost

1. 

Temporary BOWING

or

Permanent

1)  Long standstill from hot condition 2)  Uneven flow heating or cooling CAUSES

3)  Water income (quenching) 4)  Rubbing 5)  Cracking

ROTOR BOWING CAUSES

IN SITU STEAM TURBINE ROTOR STRAIGHTENING

1.  Rotor bowing causes 2.  Why in situ rotor straightening? 3.  How a bowed rotor may be straightened? 4.  Ansaldo Energia in situ experience 5.  How does it work? 6.  Tools and personnel 7.  Results, time and cost

2. WHY IN SITU ROTOR STRAIGHTENING?

Ansaldo Energia experience: TIR > 0.2 mm Very difficult to balance No possible to run up to nominal speed! What to do? Order a brand new rotor or….

The rotor is to be straightened…

(OEM) Workshop In situ

In situ with portable equipment, special tools manufactured ad hoc, client personnel & Ansaldo Energia supervision.

IN SITU STEAM TURBINE ROTOR STRAIGHTENING

1.  Rotor bowing causes 2.  Why in situ rotor straightening? 3.  How a bowed rotor may be straightened? 4.  Ansaldo Energia in situ experience 5.  How does it work? 6.  Tools and personnel 7.  Results, time and cost

3. HOW A BOWED ROTOR MAY BE STRAIGHTENED?

Different methods have been approached:

1.  Cold mechanical straightening

2.  Thermo-mechanical straightening

3.  Machining

4.  Peening

5.  Hot spotting procedure

6.  Combination of some of these

IN SITU STEAM TURBINE ROTOR STRAIGHTENING

1.  Rotor bowing causes 2.  Why in situ rotor straightening? 3.  How a bowed rotor may be straightened? 4.  Ansaldo Energia in situ experience 5.  How does it works? 6.  Tools and personnel 7.  Results, time and cost

5. ANSALDO ENERGIA IN SITU EXPERIENCE

Ansaldo Energia experienced several rotors which have been straightened with the “in situ hot spotting procedure”.

HP/IP ROTOR 15 TONS 6 M LONG

IP ROTOR 7 TONS 4,5 M LONG

LP ROTOR 15 TONS 5 M LONG

As  found  during  disassembly  @  225° 60

Run  out  [hundreds]

40

27

20 0 0 -­‐20 -­‐40 -­‐60

56

In the  ST,  coupling  disassembled,   rotor  in  turbine

45

500

1000

1500

2000

2500

3000

-­‐28 -­‐48

-­‐45

-­‐47 axial,   Z  [mm]

3500-­‐6

4000

4500

5000

IN SITU STEAM TURBINE ROTOR STRAIGHTENING

1.  Rotor bowing causes 2.  Why in situ rotor straightening? 3.  How a bowed rotor may be straightened? 4.  Ansaldo Energia in situ experience 5.  How does it work? 6.  Tools and personnel 7.  Results, time and cost

5. ANSALDO ENERGIA IN SITU EXPERIENCE

MAIN ACTIVITIES FOR A SUCCESSFULL STRAIGHTENING!

1.  NDT & RUN OUT, ROTOR DRAWING OR RE 2.  MATERIAL,TOOLS & PERSONNEL 3.  PRE-HEAT TREATMENT 4.  HOT SPOTTING PROCESS 5.  POST-HEAT TREATMENT 6.  REFINING 7.  ROTOR INTEGRITY 8.  BALANCING

5. HOW DOES IT WORK?

The hot spotting process may be roughly summarized as follows: 4)5)When cooling down, plastically it tries to shrink back its original Material expanded outside thetoborder of original 3) 1) Hot Rapid material warm up plastically the out of axially its area original cold figure 2) Warm material expand elastically, it is constrained figure but the figure is extrados, changed figure, cannot occupy theexpands sameadjacent space, inducing shrinkage higher than expansion.

5. HOW DOES IT WORK?

Spo$ng  area Dial  gauges

5. HOW DOES IT WORK?

HEAT TREATMENT •  Before the hot spotting •  After the hot spotting

5. HOW DOES IT WORK?

IN SITU STEAM TURBINE ROTOR STRAIGHTENING

1.  Rotor bowing causes 2.  Why in situ rotor straightening? 3.  How a bowed rotor may be straightened? 4.  Ansaldo Energia in situ experience 5.  How does it work? 6.  Tools and personnel 7.  Results, time and cost

6. TOOLS AND PERSONNEL

Standard TOOLS

Equipment

Special tools Upright reversing tools

Water cooled special torches and protecting shields

6. TOOLS AND PERSONNEL

HT equipment and tools Lathe

6. TOOLS AND PERSONNEL

5 Client personnel

TEAM

2 Ansaldo supervisors

3 specialized operators

Total 10 people + 2 HT

IN SITU STEAM TURBINE ROTOR STRAIGHTENING

1.  Rotor bowing causes 2.  Why in situ rotor straightening? 3.  How a bowed rotor may be straightened? 4.  Ansaldo Energia in situ experience 5.  How does it works? 6.  Tools and personnel 7.  Results, time and cost

7. RESULTS, TIME AND COST

Results:

Time for execution:

Overall cost:

IN SITU STEAM TURBINE ROTOR STRAIGHTENING

1.  Rotor bowing causes 2.  Why in situ rotor straightening? 3.  How a bowed rotor may be straightened? 4.  Ansaldo Energia in situ experience 5.  How does it works? 6.  Tools and personnel 7.  Results, time and cost