recent developments in small gas turbines -...

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Copyright © Siemens AG 2009. All rights reserved.

Recent Developments in Small Industrial Gas turbines

Ian AmosProduct Strategy ManagerSiemens Industrial Turbomachinery LtdLincoln, UK

Page 2 Nov 2010 Energy SectorCopyright © Siemens AG 2009. All rights reserved.

Content

� Gas Turbine as Prime Movers� Applications

� History

� Technology� thermodynamic trends and drivers

� core components

� Future requirements� Market developments

2


Gas Turbine as Prime Mover

Prime mover : A machine that transforms energy from thermal, electrical or pressure form to mechanical form; typically an engine or turbine.

Gas Turbines vary in power output from just a few kW more than 400,000 kW. The shaft output can be used to generate electricity from an alternator or provide mechanical drive for pumps and compressors.


SGT5-4000F

SGT6-5000F

SGT5-2000ESGT6-2000E

SGT-800SGT-700SGT-600SGT-500SGT-400

SGT-200

SGT5-8000H

SGT-100 5

287

198

168

4731

2517

13

7

113

375Figures in net MW

8SGT-300

Indu

stria

l Tur

bine

sU

tility

Tur

bine

s

Siemens Industrial gas turbine range

SGT6-8000H 266

3


Industrial Gas Turbine Product Range

47

3025

1713

87

5

SGT-800SGT-700SGT-600SGT-500SGT-400SGT-300SGT-200SGT-100

SGT-100-1S

SGT-400

SGT-300SGT-200-2S

SGT-700 SGT-800SGT-600SGT-500

SGT-100-2S SGT-200-1S Portfolio (MW)


An SGT-100 generating set is installed on Norske Shell's Troll Field platform in the North Sea

Thirty SGT-200 driven pump sets on the OZ2 pipeline operated by Sonatrach, Algeria

Power Generation

CHP

Two SGT-400 generating sets operating in cogeneration/ combined cycle for BIEP at BP’s Bulwer Island refinery, Australia

Two SGT-700 driven Siemens compressors for natural gas liquefaction plant owned by UGDC at Port Said, Egypt.

An SGT-800 CHP plant for InfraServBavernwerk’schemical plant in Gendork, Germany.

Compression Comb. Cycle

Industrial Gas TurbineProduct applications

Pumping

4


Gas Turbine RefresherComparison of Gas Turbine and Reciprocating Engine C ycle

AIR/FUEL INTAKE COMPRESSION COMBUSTION EXHAUST

Intermittent

AIR INTAKE

COMPRESSION

COMBUSTIONEXHAUST

Continuous

FUEL


Gas Turbine as Prime Mover

Operation and Maintenance�No Lubricating oil changes�High levels of availability

Fuel flexibility�Dual fuel capability �Burn Lean gases (high N2 or CO2 mixtures)�Varying calorific values

Size and Weight�High power to weight ratio

giving a very compact power source

Vibration�Rotating parts mean vibration free operation requiring simple foundations

Emissions�Very low emissions of NOx

Gas Turbine Characteristics

5


Brayton Cycle

1-2 Air drawn from atmosphere and compressed2-3 Fuel added and combustion takes place at constant pressure3-4 Hot gases expanded through turbine and work extracted

(in single shaft approx 2/3 of turbine work is used to drive the compressor)


Ideal Engine Cycle:Efficiency

Cycle efficiency is therefore only dependant on the cycle pressure ratio.

Assumption : Ideal cycle with no component or system losses.

γγ /)1(

2

1

11efficiency cycle Simple

−

−=

PP

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 10 20 30 40 50

Pressure Ratio

Idea

l the

rmal

effi

cien

cy

6


Engine Cycle:The Real Engine

Deviations from Ideal Cycle

•Aerodynamic losses in turbine and compressor blading

• Working fluid property changes with temperature

• Pressure losses in intakes, combustors, ducts, exhausts, silencers etc.

• Air used for cooling hot components

• Parasitic air & hot gas leakages

• Mechanical losses in bearings, gearboxes, seals, shafts

• Electrical losses in alternators

‘Real’ Efficiencies

• Practical simple cycle gas turbines achieve 25 to 40 % shaft efficiency

• Complex gas turbine cycles can achieve shaft efficiencies up to 50%

• However, heat rejected in the exhaust can be used :-

•Large combined cycle GT can achieve close to 60% shaft efficiency

•Cogeneration (Heat and Power) can exceed 80% total thermal efficiency


Energy Cost SavingsGT cycle parameter study

Increase Pressure ratio and firing temperatures for higher simple cycle efficiencies

35.0

36.0

37.0

38.0

39.0

40.0

41.0

42.0

43.0

280 290 300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450 460 470 480Shaft Specific Output (kJ/kg)

Sha

ft E

ffici

ency

(%

)

1350ºC1400ºC 1450ºC

25

22

20

18

FIRING TEMPERATURE

PRESSURERATIO

16

14

1300ºC1250ºC

1200ºC

7


Design Drivers :Low Specific Fuel Consumption

Higher Pressure Ratios• Increased Cycle Efficiency• Increased number of compressor / turbine stages and

therefore cost

Complex Cycles• Increased Cycle Efficiency and/or Specific Power• Can impact operability, cost and reliability

Higher Firing Temperature• Requires increased sophistication of cooling systems• Can impact life and reliability and combustor emissions


Design Drivers :Availabilty, Cost and Emissions

� High reliability.� Moderates the trend to increase firing temperature and cycle

complexity.

� Low Emissions (Driven by environmental legislation)� More difficult to achieve with high firing temperatures and

combustion pressures

� Lowest possible cost.� Encourages smallest possible frame size, i.e. high specific

power� high firing temperature.� Reduced Pressure ratios (< 20:1) to avoid auxiliary fuel

compression costs

Compromise is required in the concept design to get the best balance of parameters

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Pressure Ratio

1616

1515

1414

1313

1212

1111

1010

99

88

77

66

55

44

33

Firing Te

mperature

Firing TemperaturePressu

re Ratio

Pressure Ratio

YearYEARYEARYEARYEAR

3CT

SGT-200

SGT-100

SGT-300

Future

Machines

19501950 19601960 19701970 19801980 19901990 20002000

13001300

12001200

11001100

10001000

900900

800800

700700

Firing Temperature °C

Centrifugal Compr.

TA

TE

TF

TG

TD TB

SGT-400

Core Engine Trends:Key Parameter Trends


100

150

200

250

300

350

1975 1980 1985 1990 1995 2000 2005Year

Spe

cific

Pow

er (

kJ/k

g)

24

26

28

30

32

34

36

38

40

The

rmal

Effi

cien

cy (

%)

Specific Power Output

Thermal EfficiencyTB5000

SGT-100

SGT-200

SGT-400

Dramatic impact of increased TET and pressure ratio over last 25 years:• Specific Power increased by almost 100%• Specific Fuel Consumption reduced by over 30%• reduced airflow for a given power output and has resulted in smaller

engine footprints, reduced weight and reduced engine costs

Engine Trends:Thermal Efficiency

9


Product Evolution

SGT-300

Introduced 1995

7,900 kWe 30.5% eff

TA

Introduced 1952

750kW 17.6% eff

Developed to 1,860kW


Gas Turbine Layout- single shaft or twin shaft

Single ShaftExpansion through a single series of turbine stages.

Power transmitted through rotor driving the compressor and torque at the output shaft

Twin ShaftExpansion over 2 series of turbines.

Compressor Turbine (CT) provides power for compressor

Useful output power provided by free Power Turbine (PT)

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SGT-400 Industrial gas turbine

CompressorCombustion

system Gas GeneratorTurbine

PowerTurbine


Combustion

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Environmental AspectsPollutants and Control

Pollutant Effect Method of Control

Carbon Dioxide Greenhouse gas Cycle Efficiency

Carbon Monoxide Poisonous DLE System

Sulphur Oxides Acid Rain Fuel Treatment

Nitrogen Oxides Ozone Depletion Smog

DLE System

Hydrocarbons Poisonous Greenhouse gas

DLE System

Smoke Visible pollution DLE System

DLE - Dry Low Emissions


Exhaust Emission Compliance

�Emissions control:� Two types of combustion configuration need to be considered:� Diffusion flame� Dry Low Emissions (DLE or DLN) using Pre-mix combustion

� Diffusion flame� Produces high combustor primary zone temperatures, and as NOx is a

function of temperature, results in high thermal NOx formation� Use of wet injection directly into the primary zone to lower combustion

temperature and hence lower NOx formation

� Dry Low Emissions� Lean pre-mixed combustion resulting in low combustion temperature, hence

low NOx formation� With good design and control <25ppm NOx across a wide load and ambient

range possible

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CombustionNOx Formation

0.000001

0.00001

0.0001

0.001

0.01

0.1

1

10

100

1000

1300 1500 1700 1900 2100 2300 2500

Flame Temperature [ K ]

NO

x F

orm

atio

n R

ate

[ ppm

/ms

]

Diffusion Flame

Lean Pre-mix

Flame temperature affects thermal NOx formation


CombustionNOx Formation

RichLean

Lean burn Diffusion flame reactionzone temperature

Fla

me

tem

pera

ture

StoichiometricFAR

Flame Temperature as a function of Air/Fuel ratio

Diffusion flame

Lean Pre-mixed(DLE/DLN)

13


Combustor ConfigurationNOx product is a function of temperature

Cooling

Diffusion Combustion- high primary zone temperature

Dry Low Emissions Combustion-low peak temperature achieved with lean pre-mix combustion


DLE Lean Pre-mix Combustor(SGT-100 to SGT-400 configuration)

Air

Pilot GasInjection

Air

Main Gas Injection

Igniter

Gas/AirMix

Gas

Pilot Burner

IgniterMain Burner

Liquid Core

Radial Swirler

Double Skin Impingement

Cooled Combustor

Pre Chamber

� Robust design involving no moving parts

� Fixed swirler vanes� Variable fuel metering via pilot and

main fuel valves

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Lean Pre–Mix combustion

�Simple fuel system� Variable fuel metering via pilot and main fuel valves

� Low NOx across a wide operating range of load and ambient conditionsMAIN FLOWCONTROL

VALVE

MAIN MANIFOLD

MBLOCKVALVE

BLOCKVALVE

BLEEDVALVE

PILOT FLOWCONTROL

VALVE

PILOT MANIFOLD

MAIN FLOWCONTROL

VALVE

MAIN MANIFOLD

MBLOCKVALVE

BLOCKVALVE

BLEEDVALVE

PILOT FLOWCONTROL

VALVE

PILOT MANIFOLD


Key to success� good mixing of fuel and air

� multiple injection ports around swirler

� long pre-mix path� fuel injection as far from combustion zone as possible

� good air flow distribution� can annular arrangement with top hats

� use of pilot burner� CO control & flame stability

� use of guide vane modulation/air bleed� air flow management

CombustionDLE Lean Premix System

15


DLE System : Siemens experience

� 15million operating hours across the range (SGT-100 to SGT-800)

� Approximately 1000 DLE units

� About 90% of new orders DLE


ExperienceStable load accept/reject

Daily variations

Load Shed and Accept

kW

Daily profile for unit running more than 8000hrs DL E operation on liquid fuel.

16


Gas Fuel Flexibility

10 20 40 50 60 7030

Medium Calorific Value (MCV) High Calorific Value (HCV)

‘’Normal’’

Wobbe Index (MJ/Nm³)

SIT Ltd. Definition

Low Calorific Value (LCV)

Pipeline Quality NG

3.5 37 49 65

Siemens DLE Units operatingDLE Capability Under Development

Siemens Diffusion

Operating Experience

BIOMASS &COAL GASIFICATION

Landfill & SewageGas

High Hydrogen Refinery Gases

LPG

Off-shore rich gasIPG CeramicsOff-shore leanWell head gas

Other gas

Associated Gas


0

5

10

15

20

25

30

35

40

45

50

0 10 20 30 40 50 60 70 80 90 100

CO2 or N2 content of UK Natural Gas

Wob

be M

J/m

3

CO2N2

MCV development

UK Natural Gas

LCV Burner

The change in WI by the addition of inert species to pipeline quaility gas

Medium CV Fuel Range Definition

17


Examples of Siemens SGT Fuels Experience

NON DLE Combustion� Natural Gas� Wellhead Gases � Landfill Gas� Sewage Gas� High Hydrogen Gases� Diesel� Kerosene � LPG (liquid and gaseous)� Naphtha� ‘Wood’ or Synthetic Gas� Gasified Lignite

� DLE experience on Natural Gas, Kerosene and Diesel� DLE on fuels with high N2 and CO2 content. � DLE Associated or Wellhead Gases

5 1 0 15 2 0 25 30 3 5 40 45 5 0 5 5 6 0 6 5 7 0Wobbe Index MJ/m3

Gasified BiomassSpecial Diffusion

burner

Sewage gasstandard burner

High Hydrogen gasstandard burner

Liquified Petroleum gasmodified MPI

standard gases

UK Natural Gas

Landfill gasSpecial

Diffusionburner

Gaseous Fuel Range of Operation


Turbine

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Aerodynamic optimised design !

Minimised loss

� optimum pitch/width ratio across whole span.

� low loading� High speed

� high stage number

� low Mach numbers

� thin trailing edges

� low wedge angle

� zero tip clearance


AerodynamicsHigh Load Turbine

Computational Fluid Dynamics (CFD) used to complement experimental testing of advanced components.

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Analytical optimised design !

Reduce blade stresses

� Minimal shroud � shroud may still be desirable

for damping purposes.

� High hub/tip area ratio

� Low rotational speed.

Maximise life

� Low temperatures

� Low unsteady forces


Mechanical Design -

Improved analysis software (grid and solver) and improved hardware allow traditional ‘post-design’ to be carried out during design iterations.

Meshing of complex cooled blade could take many man months in early 90’s - now down to minutes.

More sophisticated analysis for detailed lifing studies still required after design.

20


Fatigue Life of Rotating Blades

Positions of Concern

Aerofoil

Fillets

Root Serration (including skew effects)

Blade Vibration response� Predicted by FE and measured in

Lab.� Identifies critical blade frequencies

and modes (Campbell Diagram)

High Cycle Fatigue� Fillet Radii between aerofoil &

platform� Top neck of firtree root

Low Cycle Fatigue� In areas of highest stress� Eg - blade root serrations


Mechanical Design - Vibration analysis

Campbell Diagram for LPT Blade (Blade only)

0

1000

2000

3000

4000

5000

6000

15000 15500 16000 16500 17000 17500 18000 18500 19000 19500 20000

Engine Speed (rpm)

Freq

uenc

y (H

z)

D G Palmer 3-8-01Iteration 3 version 10

mode 1

mode 2

mode 3

mode 4

mode 5

mode 6

EO3

EO6

EO9

EO10

EO11

EO17

EO18EO19EO20

100%95%

105%

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Cooling optimised design !!

Large LE radius

� minimise stagnation htc

thick trailing edge thickness and large wedge angle for cooling

thickness distribution to suit cooling passages.

Minimise gas washed surface.


Cooled Blading DesignsSGT100 > SGT300 > V2500 Aeroengine

22


SGT400 First Vane Cooling Features

Impingement Cooling

Film Cooling

Turbulators

Trailing Edge Ejection

Cast 2 Vane Segment


SGT-400 13MW Industrial Gas TurbineFirst Stage Cooled Vane

Hot Blades are life limited.

-Oxidation

- Thermal fatigue

- Creep

Life typically 24,000 hrs.

Life can be increased or decreased depending on duty and environment.

23


SGT300 8MW Industrial Gas TurbineMulti-Pass Cooled First Stage Rotor Blade

SGT-300 First Stage Cooled Rotor Blade

Ceramic Core forming Cooling Passages


HP Turbine Blade Coatings

Hot Gas Surface Coatings for Corrosion & Oxidation protection� Aluminide, � Silicon Aluminide (Sermalloy J)� Chromising� Chrome Aluminide, Platinum Aluminide� MCrAlY

Internal Coatings on Cooled Blades operating in poor environments

Ceramic Thermal Barrier Coatings� Yttria stabilised Zirconia� Plasma Spray Coatings used on Vanes� EBPVD Coatings used on rotating blades� More uniform structure for improved integrity

24


Turbine Validation Process

Design Analysis

Prototype Test

Assessevaluation and calibration of methods


New technology incorporated into existing engine platforms

SGT-100 Product Development

New ratings have been released

Aerodynamic modifications to compressor and turbine.

Power generation, 5.4MWe(launch rating 3.9MWpreviously 5.25MWe)

Mechanical Drive, 5.7MW(previously 4.9MW)

PT

HP Rotor blade• SX4 material• Triple fin shroud• Step Tip seal

Compressor Blade• Stator stages S1& S2• Rotor stages R1 & R2

25


SGT400 PT 2 Nozzle Ring

Industrial Gas Turbines Advanced Materials & Manufacturing


Bladed Turbine Disc

26


The Gas Turbine Package

In addition to the main package, the following is also required:

�Combustion air intake system�Gas turbine exhaust system�Enclosure ventilation system (if enclosure fitted)�Control system�UPS or battery and charger system


SGT-300 Industrial gas turbinePackage design – The latest Module Design

� Available as a factory assembled packaged power plant for utility and industrial power generation applications

� Easily transported, installed and maintained at site

� Package incorporates gas turbine, gearbox, generator and all systems mounted on a single underbase

� Preferred option to mount controls on package, option for off package.

� Common modular package design concept

� Acoustic treatment to reduce noise levels to 85 dB(A) as standard (lower levels available as options)

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Typical Compressor Set


Combustion Air Intake

Enclosure Air Inlet

On-Skid Controls

Fire & Gas System

Interfaces

Lub Oil Cooler

Enclosure Air Exit

1

2

3

4

5

6

7

SGT-400New Package Design Minimised customer interfaces reducing contract execution/installation costs

1

2

3

4

5

67

� Highly flexible modular construction

� Customer configurable solutions based upon pre-engineered options

� Standard module interfaces to allow flexibility and inter-changeability

� Additional functionality provided dependent upon client needs

� Base design provides common platform for on-shore and off-shore PG and MD

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Future direction


Future Trends- guided by market requirements

Universal demand for further increases in efficiency and reliability, and reduction in cost.

Oil & Gas (Mech drive and Power Gen)� Fuel flexibility - associated gases, off-gases, sour gas� Remote operation� Emissions -inc CO2

Independent Power Generation� Fuel flexibility - syngas, biofuels(?), LPG � Flexible operation - part load operation� Distributed cogeneration (rather than centralised generation) � Emissions - inc CO2

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Oil and Gas remote operations / fuel flexibility

•First application of its kind in Russia (Western Siberia) burning wellhead gas which was previously flared•Solution:

Three SGT-200 gas turbine•Output 6.75 MWe each•DLE Combustion system•Guaranteed NOx and CO emission levels of 25ppm•Min. air temp. (-57oC)•Max. air temp. (+34oC)

•Gas composition with Wobbe Index >45MJ/m3

•Total DLE hours approximately 22,300 hours for each unit•Significant reduction of emissions : 80-90% reduction of NOx level•Siemens has supplied 135 gas turbines for Power Generation , Gas compression and pumping duty throughout the Russian oil & gas industry


Power Generationre-emergence of cogeneration

BOILEROR

DRIER

GRID

WATER

FUEL

PRODUCT / STEAM

~

30


Thank You

recent developments in small gas turbines -...

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