COMBINED CYCLE POWER PLANTS - Munich Re€¦ · New Gas Turbines Market Requirements: Maximum unit output Maximum efficiency Operation flexibility Cleanest exhaust gases Good serviceability

COMBINED CYCLE POWER PLANTS

Have you ever seen a Gas Turbine?

How many types we can find?

New Gas Turbines

https://www.bmw.de/de/neufahrzeuge/7er/limousine/2019/bmw-7er-limousine-

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Gas turbines, combined cycle power plants 3

Gas Turbine Types.

Aeroderivatives

GE LM2500Around 6mts engine

BMW series 7

https://www.bmw.de/de/neufahrzeuge/7er/limousine/2019

New Gas Turbines


Gas Turbine Types.

Heavy Duty

BMW series 7

SGT5-9000HLAround 13 mts engine

https://www.bmw.de/de/neufahrzeuge/7er/limousine/2019

New Gas Turbines

Gas Turbine Cross Section


https://new.siemens.com/mx/es/productos/energia/generacion/turbinas-de-gas.html

Combustor

CompressorTurbine

New Gas Turbines

Gas Turbine


https://new.siemens.com/mx/es/productos/energia/generacion/turbinas-de-gas/sgt-9000hl.html

New Gas Turbines

Protection System and Auxiliaries

7Cogeneración Turbinas Tecnología Aeroderivada

▪ Protection ▪ Auxiliary

CO2, fire suppression

system

Integrated Control

SystemVibration Post- Lub System

Batery System 125 y 24 VDC

x

y

x

y

New Gas Turbines

Gas Turbine Power Plant (simple cycle)


New Gas Turbines

Market Requirements:

▪ Maximum unit output

▪ Maximum efficiency

▪ Operation flexibility

▪ Cleanest exhaust gases

▪ Good serviceability

▪ Low price / kW

New Gas Turbine Technology

9Gas turbines, combined cycle power plants

New Gas Turbines

Development of GTS Power Output


0

100

200

300

400

500

600

700

39 45 48 64 70 77 82 85 93 96 98 2003 2011 2017 2019

New Gas Turbines

Development of net Efficiency


0

10

20

30

40

50

60

70

500 600 700 80058

1970

90077

1980

100083

1985

110096

1990

12001501995

1300240

2000

1400320

2005

1500°C375MW

2010

1600°C500MW

2017

Combined cycles

Single cyclesconv. TPP

Net E

ffic

iency in %

New Gas Turbines

Firing class (only Heavy Duty)

1,000 °C

1,100 °C

1,200 °C

1,300 °C

1,400 °C

1,500 °C

1,600 °C

1,700 °C

H/J-class

G-class

F-class

E-class

220-265 MW

120-170 MW

<300 MW


300-590MW

New Gas Turbines

Technical challenges


▪ New combustion technologies

(low NOx ↔ flame stability ↓)

▪ Higher inlet temperatures

(up to 1600° C ↔ material properties ↓)

▪ More sophisticated materials

(CC → DS → SX)

▪ More sophisticated cooling systems

(convective + impingement + film

cooling)

▪ More sophisticated coatings

(oxidation resistance, TBC for insulation)

▪ Higher precision (smaller tolerances)

▪ Reduction of leackages

CC DS SX

New Gas Turbines

Type Overview F-Class

F-Class

50 Hz 60 Hz

Alstom GT26 GT24

GE 9F.05 7F.05

MHI 701F 501F

Siemens SGT5-4000F SGT6-5000F

Usually either up- or downscaled


New Gas Turbines

Up- or downscale

OEMs: this is a proven model, just scaled up/down

But: life is not that easy, not everything can easily

be scaled despite application of dimensionless

numbers and CFD:

▪ Compressor: boundary layer effects, relative

gap width

▪ Combustor: combustion processes, pulsations

(thermofluid-dynamics)

▪ Turbine: heat transfer processes, wall

thickness (cooling)


New Gas Turbines

Main GT types (selection)

Heavy Duty

GE Frame 6 (50 or 60 Hz)

Frame 7 (60 Hz)

Frame 9 (50 Hz)

Siemens SGT5-4000F (50 Hz)

SGT6-5000F (60 Hz)

SGT5/6-8000HL

Alstom GT13E2 (50 Hz)

GT24 (60 Hz)

GT26 (50 Hz)

Mitsubishi M501 (60 Hz)

M701 (50 Hz)

Aeroderivative or Hybrid

GE LM 2500

LM 6000

LMS 100

Siemens SGT 100, 200, 300, 400

SGT 500, 600, 700, 750, 800

Solar Taurus

Mars

Titan

RollsRoyce RB211

Trent 60

United Technologies FT8


New Gas Turbines

Main GT types

Heavy Duty Aeroderivative

50 – 593 MW 1 - 117 MW

Low power/weight ratio High power/weight ratio

One shaft Two or three shafts

Welded or built rotors, casted casings Built rotors, Sheet metal casings

One horizontal split level Multiple radial split levels

Moderate pressure ratio, usually 15-25 High pressure ratio, 30-45

High exhaust temperatures Moderate exhaust temperatures

Fixed speed (typically 3.000 min-1 for 50Hz,

3.600 min-1 for 60 Hz)

Variable speed gas generator,

fixed speed power turbine

Ideal for base load applications Ideal for peaking applications

High efficiency at base load,

low efficiency at part load

Good efficiency also at part load

Long start up time Fast start up time

Repair/overhaul usually on site Repair/overhaul in service centres


New Gas Turbines

Next Generation

50 Hz 60 Hz

Alstom GT36-5 GT36-S6

GE 9HA.02 7HA.02

MHI 701 J 501 J

Siemens SGT5-8000HL SGT6-8000HL

▪ Increased turbine inlet temperature: 1500° C – 1600° C

▪ Some turbines with closed-loop external steam cooling of the combustor, but the trend is

to go back to air cooling (flexibility)

▪ Increased compressor efficiency, mass flow and pressure ratio with less stages

▪ High efficiencies and low emissions at low load (flexibility)

▪ Combined cycle efficiency: ≥ 62 %


New Gas Turbines


Loss potential:

▪ Higher thermal stresses and elongations

▪ Overheating, uneven distribution of heat

▪ Rubbing of rotating parts

(smaller tolerances, at larger thermal elongation)

▪ New and unproven materials

▪ Unexpected behaviour / losses from unproven modifications


New Gas Turbines

Our worldwide loss experience with gas turbines

Some Loss examples:

▪ Over speed

▪ Ladder in Compressor inlet

▪ Compressor loss

▪ Combustor loss

▪ Turbine loss

Loss analysis:

▪ Increase of average GT losses

▪ GT losses versus GT values

▪ Causes of Loss


New Gas Turbines

Loss example 1: Over speed


▪ Problems with the control room

electronics

▪ Faulty operation (manual opening of

the main circuit breaker)

▪ Failure of over speed protection

▪ Resulted in self destruction of the

GT due to over speed

▪ This is one of the rare cases where

lost blades penetrated the casing

▪ Total loss of GT turbo set

Copyright Cunningham


New Gas Turbines

Loss example 2: Ladder in Compressor Inlet


Human factor:

▪ A ladder has been forgotten in the

compressor inlet

▪ During start up it has been sucked in

▪ Resulting in severe damage to the

compressor blading

Remember:

▪ Large GT suck in up to a half ton of

air (500m3) per second

▪ Any object or liquid left in the inlet

would go through the compressor



New Gas Turbines

Loss example 3: Compressor Loss


▪ One blade of the second row broke

off during operation

▪ This blade worked though the whole

compressor and damaged all

remaining blading (rotor and stator)

and compressor casing

▪ The milled material penetrated into

combustor and turbine cooling

systems

▪ Overheating of combustor and

turbine

▪ Total loss of the GT

Copyright Munich Re

Copyright Munich Re

New Gas Turbines

Loss example 4: Combustor Loss


▪ In order to achieve low NOX

emissions combustors are operating

today in so-called lean premix mode.

▪ This operation mode can sometimes

result in unstable combustion or

combustor humming.

▪ These vibrations led to damage on

the combustor can.

▪ Parts broken off damaged the down-

stream turbine blading.

Copyright Munich Re

Copyright Munich Re

New Gas Turbines

Loss example 5: Turbine loss


▪ During a planned inspection cracks

were discovered on turbine blades

of row 3.

▪ There was a misinterpretation of

these cracks.

▪ It was decided to continue operation.

▪ After short operation period these

blades broke off and caused

substantial down-stream damage.

Copyright AZT

Copyright AZT

New Gas Turbines

Increase of Average GT Losses


Four periods were analysed:

▪ 1994 – 2003:

153 losses, average paid

loss: €3.8m

▪ 2001 – 2007:

116 losses, average paid loss:

€5,2m

▪ 2012:


€6,2m

▪ 2013 – 2014:


€11,6m

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

1994 -2003 2001 - 2007 2012 2013 - 2014

€3.8m €5,2m 6,2m 11,6m

Result: Increasing average GT losses!

New Gas Turbines

Causes of Loss in Stationary Gas Turbines


40

1210

5

11

9

13

Faulty planning, calculation, design Faulty erection Faulty manufacture / repair

Faulty in material Faulty operation Faulty maintenance

Exterior influences

◼ Product defects 67 %

◼ Operational failures

◼ Exterior influences

New Gas Turbines

General Insurance Aspects:

▪ For risk evaluation, all risk details (GT type, output in MW, present stage of

experience, last modifications etc.) need to be ascertained

▪ A GT type/ modification is regarded proven only after 8000 h of successful

operation and 100 starts

▪ For unproven types/ modifications no Manufacturers' Risk or Guarantee covers

shall be granted

▪ For test operation min. dd.: 20 % of loss, min. 2 % of SI e.g. €1,000,000 for most

medium larger gas turbines

▪ Rating only on basis of statistically evaluated rates



New Gas Turbines

Insurance Aspects for operational cover (MB):

▪ We strongly recommend to apply our endorsement 333.

▪ This endorsement establishes depreciation adjustment for components

along the hot gas path of gas turbines.

▪ This depreciation of the hot gas path components is necessary since

they have a limited designed life time.

▪ “New for old” would be betterment.

▪ For „F-class“ gas turbines the value of the hot gas path components

can be in the range of €15m to €20m.



New Gas Turbines

Schematic representation of a combined cycle

power station


The residual heat of

exhaust gases from a gas

turbine (1) is a source of

heat for a downstream

steam generator (2), which

generates steam for a

steam turbine (3).Electric

GeneratorCompressor

Combustor

Turbine

Air Fuel

Exhaust

gas

Chimney

Heat recovery

steam

generator (2)

Steam

turbine (3)Electric

GeneratorPump

Condenser

Gas turbine (1)

New Gas Turbines

Single-shaft Combined Cycle Power Plant


Com-

buster

Waste heat boiler

Turb. Compr. HP MP/ LP Generator

Air Steam turbine

Condenser

re-heated steam

Steam to reheaterHP steam

Gas turbine

Flue gas to chimney

Hot gas

New Gas Turbines

Combined Cycle Power Plant single shaft


ca

. 4

5 m

ca. 125 m

Stack

HRSG

Gas turbine Steam turbine

GeneratorTransformer

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Gas Turbine Power Plant (Combined cycle)


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Gas turbo set and HRSG during erection


Copyright Munich Re

New Gas Turbines

2 Gas turbo sets during erection


Copyright Munich Re

New Gas Turbines

▪ Increased efficiency by use of waste heat of GT (54 % to 62 %)

▪ Low specific capital requirement [€/kW], low maintenance costs

▪ Reduced emissions

▪ Air cooled gas turbine, i.e. Low cooling water consumption

▪ High availability

▪ Erection by stages possible

▪ Short delivery times ?

▪ Compactness ?

▪ Fuel utilization reaches level of up to 87 % in cogeneration application

▪ Operational Flexibility

Advantages of CCPP


New Gas Turbines

Operational Flexibility of CCPPs


New Gas Turbines

▪ Results: faster start-up times

▪ 27-30 minutes for single shaft plants (hot startup), ca. 30 minutes for 2x1 CCPP

Operational Flexibility of CCPPs


0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80 90 100 110

Po

wer

[%]

Time [%]

Cycling Plant

Standard Plant

Gas turbine

ignition

Plant start-up complete

New Gas Turbines

Questionnaire:

▪ Names and references of the contractors, manufacturers and suppliers

▪ Time schedule (erection period, testing period)

▪ Break down of values of items to be insured

▪ Technical description of items to be insured, especially: type of turbo generators

(gas or steam), power output

▪ Description of site and location

▪ Scope of cover

▪ TA on site, are there LTSA or SA in place?

Required underwriting information


New Gas Turbines

Combined Cycle Power Plant


Time schedule – bar chart

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

month

GT set 1

GT set 2

steam cycle 1

GT set 3

GT set 4

steam cycle 2

Comb. Cycle 1

Comb. Cycle 2

— Construction — Testing — Commercial operation GT set — Comercial operation CC

Testing: gas turbine 4 weeks + combined cycle 8 weeks.

Commercial operation GT sets 1 and 3 before testing CC: 4 weeks

New Gas Turbines

Main components in a 450 MW CCPP


Approx. %

Civil Works

▪ Building Structures

20 %

2 Gasturbo Generator Sets (150 MW) 33 %

2 Heat Recovery Steam Generators 10 %

1 Steam Turbo Generator Set (150 MW) 10 %

Instrumention and Control System,

Lubrication System, Transformers, Switchboards, Balance of

Plant (BoP)

27 %

100 %

New Gas Turbines

Premium = Rate times Sum Insured


New replacement values for GT generator sets

150

200

250

300

350

400

450

500

10 20 30 40 50 75 100 150 175 200 225 250

Unit size in MW

Price

in

€ / k

W

New Gas Turbines

New Replacement Value (NRV):

▪ Combined Cycle Power Station ~ 500 € / kW

▪ Gas Turbo Generator Sets ~ 250 € / kWGT

▪ Steam Turbo Generator Set ~ 140 € / kWStT

▪ Heat Recovery Steam Generators ~ 80 € / kWelGT

Sum Insured


New Gas Turbines

Lessons Learned

The following are lessons learned by Endesa about combined cycles, according to Tomás Alvarez Tejedor, the head of combined cycle

technology and maintenance department:

• Acquire the last proven technology, not the latest

• Power plants are true test stands for gas turbine technologies

• All possible failure modes of latest gas turbines are still unknown

• Operation outside ideal conditions significantly affects performance and durability

• Cyclic operation is still uncharted territory

• There is little competition for aftermarket repairs for recent gas turbines

• Maintenance cost is nearly twice the initial cost

• Gas turbines are consumable parts

• Gas turbine design is always inconclusive and subject to continuous improvement

• Component repair should be certified and regulated

• Condition-based maintenance could reduce maintenance costs

• Notable differences occur in calculation formulas for equivalent operating hours

• “Infant mortality” failures plague plants in the first three years of operation

• Operation modes influence maintenance costs

• The latest technology is usually a high-risk one

• Over 70% of the cost of electricity is fuel cost

• Operation mode affects not only the fixed cost, but all variable costs

• Technology immaturity affects all variable costs


Source: Nov./Dez. 2006 Turbomachinery International

Thank you very much

for your attention

Nilton Diaz

Questions?

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Use the code: 79 52 40 7

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Documents

COMBINED CYCLE POWER PLANTS - Munich Re€¦ · New Gas Turbines Market Requirements: Maximum unit output Maximum efficiency Operation flexibility Cleanest exhaust gases Good serviceability