View
4
Download
0
Category
Preview:
Citation preview
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-
entdecken.html?ds_rl=1272952&tl=sea-gl-GSP%20(BS)%20BMW%207er-mix-miy-
7%20series%20%C3%BCbergreifend-sech-BMW%207er-.-e-bmw%207-.-
.&clc=BMW_se&gaw=sea:1957596762_kwd-
89321538&gclid=CjwKCAjw74b7BRA_EiwAF8yHFF6kXHfCsZ9IwtCDaSsYeycsm1j48Y
n13y8B5g4oIWInfNPmQOBH0xoC1mAQAvD_BwE&gclsrc=aw.ds
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 turbines, combined cycle power plants 4
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
Gas turbines, combined cycle power plants 5
https://new.siemens.com/mx/es/productos/energia/generacion/turbinas-de-gas.html
Combustor
CompressorTurbine
New Gas Turbines
Gas Turbine
Gas turbines, combined cycle power plants 6
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)
Gas turbines, combined cycle power plants 8
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
Gas turbines, combined cycle power plants 10
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
Gas turbines, combined cycle power plants 11
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
Gas turbines, combined cycle power plants 12
300-590MW
New Gas Turbines
Technical challenges
Gas turbines, combined cycle power plants 13
▪ 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
Gas turbines, combined cycle power plants 14
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)
Gas turbines, combined cycle power plants 15
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
Gas turbines, combined cycle power plants 16
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
Gas turbines, combined cycle power plants 17
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 %
18Gas turbines, combined cycle power plants
New Gas Turbines
New Gas Turbine Technology
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
19Gas turbines, combined cycle power plants
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
20Gas turbines, combined cycle power plants
New Gas Turbines
Loss example 1: Over speed
Gas turbines, combined cycle power plants 21
▪ 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
Copyright Cunningham
New Gas Turbines
Loss example 2: Ladder in Compressor Inlet
Gas turbines, combined cycle power plants 22
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
Copyright Cunningham
Copyright Cunningham
New Gas Turbines
Loss example 3: Compressor Loss
Gas turbines, combined cycle power plants 23
▪ 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
Gas turbines, combined cycle power plants 24
▪ 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
Gas turbines, combined cycle power plants 25
▪ 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
Gas turbines, combined cycle power plants 26
Four periods were analysed:
▪ 1994 – 2003:
153 losses, average paid
loss: €3.8m
▪ 2001 – 2007:
116 losses, average paid loss:
€5,2m
▪ 2012:
27 losses, average paid loss:
€6,2m
▪ 2013 – 2014:
45 losses, average paid loss:
€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
Gas turbines, combined cycle power plants 27
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 Turbine Technology
28Gas turbines, combined cycle power plants
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 Turbine Technology
29Gas turbines, combined cycle power plants
New Gas Turbines
Schematic representation of a combined cycle
power station
Gas turbines, combined cycle power plants 30
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
Gas turbines, combined cycle power plants 31
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
Gas turbines, combined cycle power plants 32
ca
. 4
5 m
ca. 125 m
Stack
HRSG
Gas turbine Steam turbine
GeneratorTransformer
New Gas Turbines
Gas Turbine Power Plant (Combined cycle)
Gas turbines, combined cycle power plants 33
New Gas Turbines
Gas turbo set and HRSG during erection
Gas turbines, combined cycle power plants 34
Copyright Munich Re
New Gas Turbines
2 Gas turbo sets during erection
Gas turbines, combined cycle power plants 35
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
36Gas turbines, combined cycle power plants
New Gas Turbines
Operational Flexibility of CCPPs
Gas turbines, combined cycle power plants 37
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
38Gas turbines, combined cycle power plants
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
39Gas turbines, combined cycle power plants
New Gas Turbines
Combined Cycle Power Plant
Gas turbines, combined cycle power plants 40
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
Gas turbines, combined cycle power plants 41
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
Gas turbines, combined cycle power plants 42
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
43Gas turbines, combined cycle power plants
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
44Gas turbines, combined cycle power plants
Source: Nov./Dez. 2006 Turbomachinery International
Thank you very much
for your attention
Nilton Diaz
Questions?
Your feedback matters
Please visit: www.menti.com
Use the code: 79 52 40 7
Feedback Form
Recommended