Large capacity supercritical sets

• Over all Efficiency can be improved by:

Improving internal efficiency

Adoption of advance steam parameters

Improving thermal efficiency

Improvement in efficiency with Increasing inlet parameters for Steam turbines

Parameters for Critical State• Steam Pressure > 221.2 Bar• Steam Temperature > 374.15 Deg C

Ultra Supercritical Pressure 300 BAR

Increase in steam parameters results in significant improvement in efficiencyWith higher cycle efficiency, the supercritical cycle offers lower emission & lesser pollutants – SOX , NOX & CO2

05

1015202530354045

500 MW 660 MW

Sub critical170 ata / 537 °C / 537 °C

Super Critical247 ata / 565 °C / 593 °C

Impr

ovem

ent

4.3 %

Entropy

Tem

pera

ture

Supercritical Cycles

Details of Super-Critical Units in 10th , 11th , 12th &13th 5 Year Plans

  Sub Critical (MW)

660 MW (No.)

800 MW (No.)

Super Critical (MW)

TOTAL MW

10th Plan 9620 0 0 0 962011th Plan 45470 7 1 5420 5089012th Plan 18270 25 33 42,900 61,17013th Plan 4000 36 36 52,560 56,560

Power Projections

Comparison between SubCritical & SuperCritical (MW)

9620

45470

18270

40000

5420

42,900

52,560

0

10000

20000

30000

40000

50000

60000

10th Plan 11th Plan 12th Plan 13th Plan

Total Subcritical (MW) Total Super critical (MW)

Introduction of large capacity super critical Steam Turbines with power

output 660MW

Cross sectional arrangement of 500 mw Steam turbine

Cross sectional arrangement of 660 mw Steam turbine

Cross sectional arrangement of 800 mw Steam turbine

Module 500MW 660MW 800MWHP Turbine H30-100 H30-100 (H70-V4) H30-100 (H70-V4)

IP Turbine M30-63 M30-63 (I50-V2) M30-100 (I60-V2)

LP Turbine N30-2x10 N30-2x12.5 (L2x12.5) N30-4x8 (L4x8)

HP Valves 2xFV320 2xFV250 2xFV250

IP Valves 2xAV560 2xAV560 2xAV560

Steam Turbine module configuration

PARAMETERS UNITSUBCRITICAL SUPERCRITICAL

500 MW 660 MW 800 MWMS PRESSURE ATA 170 247 247MS TEMPERATURE oC 537 565 565MAIN STEAM FLOW T/HR 1500 2000 2425REHEAT PRESSURE ATA 40.5 54 54RH TEMPERATURE oC 537 593 593REHEAT FLOW T/HR 1335 1740 2090FINAL FEED WATER TEMP. oC 253 271 290CONDENSATE FLOW T/HR 1180 1515 1860

Comparison of parameters

Overview of a Large capacity set with super critical parameters

Constructional details of HP turbine

Inner Casing

Inlet

Outer Casing-Barrel type

Exhaust

Shaft Seal-Front

Shaft Seal-Rear

• Single flow • Double shell casing

– Inner casing axially split– Outer casing barrel type &

axially divided– Single exhaust in L/H

• Mono block rotor• First stage diagonal blading• Provision for extraction• Over load valve• Casing mounted valves• Transported as single unit

• Single flow • Double shell casing

– Inner casing : axially split– Outer casing: Barrel type– Single exhaust in L/H

• Mono block rotor• Reaction blading with Integral

shroud• Casing mounted valves• Transported as single unit

HP Turbine

500 MW

660 MW

HP Turbine

HP Turbine

HP Turbine

For Over load valve

Extraction Chamber

Overload valve

HP Turbine

Section through HP admission with sealing between HP inner and outer shell

Section through HP admission without sealing between HP inner and outer shell

500 MW 660 MW

HP Turbine

HP Turbine Additional Features

Outer Casing (rear)G17CrMo5-10 HW 19582 G-X12CrMoVNbN9-1

X22CrMoV12-1 HW 10687

Rotor

Inner Casing

HP Moving & Guide Blades (rear) X12CrMoWVNbN10-1-1

HW19488

G-X12CrMoVNbN9-1Outer Casing (front)

X12CrMoWVNbN10-1-1

HP Moving & Guide Blades (front)

Materials of HP turbine

HP Turbine with Breech-Nut connection

Breech Nut

Constructional details of IP turbine

• Double flow • Double casing design with horizontal split• Inlet from Lower half• Single Exhaust from upper half• Extraction connections from lower half• Admission blade ring with cooling

Inner Casing

Inlet

Exhaust

Outer Casing

Extraction

Inlet

Rotor

• Double flow • Double shell casing with horizontal split• Mono block rotor• Reaction blading• Inlet from Upper & Lower halves• Two exhaust in L/H• Extraction connections from Upper & lower half

IP Turbine

Inlet

Exhaust

500 MW

660 MW

IP Turbine –Inlet Ring

•Reduction in wall temperature of the Rotor•Reduction in Creep damage•Reduction of Cracking•Increase of Life cycle time

IP Turbine –Inlet Ring

Outer CasingGGG 40.3 HW 19793

G-X12CrMoVNbN9-1

Rotor

Inner Casing

X12CrMoWVNbN1011HW19488

HW19688

Guide Blades: X19CrMoVNbN111

IP Moving (initial stg.) : NiCr20TiAl

Materials of IP turbine

Guide Blades: X19CrMoVNbN111

IP Moving (rear stg.) : NiCr20TiAl

IP Turbine with Casing mounted valves

Constructional details of LP turbine

• Double flow • Three shell casing• Horizontally split• Mono block rotor• Reaction blading• Rigid coupling

• Double flow• Double shell casing• Single admission from top half• Outer Casing & condenser rigidly

connected• Push rod arrangement to minimize

axial clearances• Mono block rotor• Inner / Outer casing fabricated

LP Turbine

LP Turbine - 500MW LP Turbine - 660 MW

LP Turbine

EXHAUST DIFFUSER

ROTOR

LP INNER INNER CASING

LP INNER OUTER CASING

GUIDE BLADE CARRIERS

LP LONGITUDINAL GIRDER

LP FRONT WALL

ATMOSPHERIC RELIEF DIAPHRAGM

LP Turbine - 500MW

LP Turbine – 660MW

EXHAUST DIFFUSER

ROTOR

LP INNER OUTER CASING

LP SIDE WALL

LP END WALL

ATMOSPHERIC RELIEF DIAPHRAGM

CASING UPPER PART

LP Turbine – 660MW

Arrangement of thrust bolt for minimizing axial clearances

26NiCrMoV14-5 HW 19373

X20Cr13 HW 10786

Rotor

Inner Casing

LP Moving & Guide Blades Drum Stages

X10CrNiMoV 12-2-2 HW 19392

Last Stage Moving Blade

X2CrNi12HW 18802Hollow Guide Blades

Fabricated ST 37-II AA10401/10119

Outer Casing

Materials for LP turbine

Fabricated ST 37-II AA10401/10119

Arrangement of thrust bolt for minimizing axial clearances

Banana type guide bladeLast stages of LPT

Improved cylindrical profile blade (TX) HPT / IPT middle & LPT initial stages

Twisted profile blade (F)HPT / IPT rear stages

3 Dimensional blade (3 DS)HPT / IPT initial stages

Turbine Blading

Fabricated bearing pedestals Cast bearing pedestalsGGG-40.3 Nodular Casting

Bearing Pedestals

Governing System

660 MW steam turbine equipped with high pressure electro-hydraulic governing system

Advantage:• Compact design• Less control fluid piping• Less erection and commissioning

time

Characteristics 500 MW(Low Pressure Gov.)

660 MW(High Pressure Gov.)

Operating Pressure 8/32 Bar 160 Bar

IP valves Suspended Casing mounted

Control signal toActuator

Hydraulic Electronic

Size of Actuators Bulky Compact

Control & ProtectionElements

Hydraulic / Electro-hydraulic

Electronic

Governing System

Advantages of high pressure EHA based governing system

• Bulky servomotors replaced with compact actuators leading to compact layout in TG hall

• Governing & protection racks replaced by electronic systems

• Faster response due to state of art electronic control and protection systems

• Reduced manufacturing time at shop• Turbine driven MOP replaced with motor driven

pump• Mechanical Emergency governor replaced by

electronic protection system, eliminating actual over speeding at site

Additional features

• Less noise because of latest features hence no cleading up to 85 db

• Hydraulic turning wheel for barring replaced by Hydraulic turning motor at front bearing pedestal similar to 250 MW

• Steam strainer elements built in the valves resulting in elimination of strainer housings

LP Bypass valve

Advantages: 1. Considerable reduction in overall space 2. Use of just one actuator, lower control fluid

consumption and simplified C&I. Small sized HPSU

3. Overall weight of valve assembly will be less4. Less number of O&M Spares needed5. Procurement and O&M cost will be much

less

In 500 MW LP Bypass, combined stop & control valve is used

For 660 MW, single stem LP Bypass valve having both stop & control function will be used

Lub oil system in 500 MW set consists of

• Main Oil Tank• Main Oil Pump (Turbine Driven)• Auxiliary Oil Pump (2X100%) • Emergency Oil Pump • Jacking Oil Pump (2X100%)• Oil Vapour Exhausters (2X100%)• Oil Coolers (2X100%)• Duplex Oil Filters (Lub Oil & Jacking Oil)• Seal Oil Storage Tank• Temp control valve, butterfly, pressure limit

valves

LUB OIL MODULE

el. temperature control valve, Toil=50°C

2x100% lube oil pumps,centrifugal pumps, 6 bar

Emergency oil pump, 220V battery voltage

2x100% lifting oil pumps, vane pumps, max. 175bar,switch off at 9s-1

oil vapor demister, acc. to german regulations (TA-Luft)

main throttle, min. flow

lube oil double filter (2x100%, 25µm)

return line

2x100% plate heat exchanger,controlled by oil side

2x100%lifting oil filter 25µm,pressure control valve

tank

module design exemplary

Off-line-filterOLF60, 3µm

Lub Oil Module in 660 MW

OIL MODULE

example

Lub Oil Module in 660 MW

• Turbine driven main oil pump in 500 MW set is replaced by motor driven lub oil pump in 660 MW

Advantage:1. Injectors in system are avoided2. Interconnecting pipe between injectors &

MOP is no more required3. Smaller main oil tank

Main Oil Pump

• Electric actuators of angle drain valves replaced by pneumatic actuators

Advantage: In case of loss of control air, valves move immediately in the defined fail safe position.

A motorised valve remains in the actual position in case of power loss and need to be operated manually

Drain Valves

Steam Strainers

Steam strainers in 660 MW unit are located inside turbine valves (ESV & IV) and hence separate strainer housings in MS & HRH lines are eliminated.

TThhaannkks ……s ……

STEAM TURBINE Unit 1 Unit 2

1 H. P. Turbine SAG SAG

2 I. P. Turbine SAG BHEL

3 L. P. Rotor SAG BHEL

4 L. P. Inner casing SAG BHEL

5 L. P. Outer casing BHEL BHEL

6 Cross Around Piping SAG BHEL

7 FB Pedestal SAG BHEL

8 HP Pedestal SAG BHEL

9 IP Pedestal SAG BHEL

10 LP Pedestal SAG BHEL

11 ESV & CV SAG BHEL

12 IVCV SAG BHEL

13 LPBP Valve BHEL BHEL

14 Governing Control Rack NA NA

15 LPBP Control Rack NA NA

16 Valves (CRH NRV, EXTRACTION NRVS, OVERLOAD VALVES)

SAG BHEL

17 Instruments & Rack SAG SAG

18 Tools & Tackles SAG NA

19 TG Dec Embedments BHEL BHEL

20 Oil Module BHEL BHEL

21 Piping and Mounting Accessories (Turbine Integral Piping System)

BHEL BHEL

25 Base Plate Assembly BHEL BHEL

800 MW TG SETS660 MW BARH TG SETS

Division of Work

660 MW TG SETS

AVAILABILITY OF DOCUMENTS:

-The schedule given by Siemens indicates documents flow starting Oct’ 2009 up to end of 2010.

-This does not suit BHEL

e.g. – LP outer casing is to be supplied by BHEL by February 2011 while Siemens’ date of supply of document is Oct’ 2010. Similar case exists for other assemblies for set no.-2 (in BHEL scope).

- Preponment of 6-12 months required.

- Detailed letter being sent to Siemens by 10th July 2009.

- Documents for HP module shall be available from Siemens after signing of TCAE3.

660 MW TG SETS

MANUFACTURING FACILITIES FOR TURBINES:

• Facility planned for weld overlay for HP / IP rotors.

• No other special facility is required for manufacture of these turbines.

• Machining facilities had been evaluated on the basis of 660 MW documentation received for Swarzpumpe project.

• Documentation for Barh project is yet to be received. It is envisaged that being a modular design, major changes necessitating new machines are not expected.