Recent Developments in Small Industrial Gas turbines

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Recent Developments in Small

Industrial Gas turbines

Ian Amos

Product Strategy Manager

Siemens Industrial Turbomachinery Ltd Lincoln, UK

Content

Gas Turbine as Prime Movers

Applications

History

Technology

thermodynamic trends and drivers

core components

Future requirements

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Page 3 Nov 2010 Energy Sector

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 SGT5-2000E SGT6-2000E SGT-800 SGT-700 SGT-600 SGT-500 SGT-400 SGT-200 SGT5-8000H SGT-100 5 287 198 168 47 31 25 17 13 7 113 375 Figures in net MW 8 SGT-300 In d u s tr ia l T u rb in e s U ti lit y T u rb in e s

Siemens Industrial gas turbine range

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Industrial Gas Turbine Product Range

47 30 25 17 13 8 7 5 SGT-800 SGT-700 SGT-600 SGT-500 SGT-400 SGT-300 SGT-200 SGT-100 SGT-100-1S SGT-400 SGT-300 SGT-200-2S SGT-700 SGT-800 SGT-600 SGT-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 InfraServ Bavernwerk’s chemical plant in Gendork, Germany.

Compression Comb. Cycle

Industrial Gas Turbine Product applications

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Gas Turbine Refresher

Comparison of Gas Turbine and Reciprocating Engine Cycle

AIR/FUEL INTAKE COMPRESSION COMBUSTION EXHAUST

Intermittent AIR INTAKE COMPRESSION COMBUSTION EXHAUST 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

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Brayton Cycle

1-2 Air drawn from atmosphere and compressed

2-3 Fuel added and combustion takes place at constant pressure

3-4 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. γ γ 1)/ ( 2 1

1

1 efficiency

cycle

Simple

−













−

=

P

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 10 20 30 40 50 Pressure Ratio Id e a l th e rm a l e ff ic ie n c y

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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 Savings GT 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 43.0 280 290 300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450 460 470 480 Shaft Specific Output (kJ/kg)

Sh a ft Ef fic ie n c y ( % ) 1350ºC 1400ºC 1450ºC 25 22 20 18 FIRING TEMPERATURE PRESSURE RATIO 16 14 1300ºC 1250ºC 1200ºC

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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 powerhigh 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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P re ss u re R a ti o 16 16 15 15 14 14 13 13 12 12 11 11 10 10 9 9 8 8 7 7 6 6 5 5 4 4 3 3 Firing Temp eratur e Firing Temp eratu re Pressu re Ra tio Pres sure Ratio Year YEAR YEAR YEAR YEAR 3 C T S G T -2 0 0 S G T -1 0 0 S G T -3 0 0 F u tu re M a ch in e s 1950 1950 19601960 19701970 19801980 19901990 20002000 1300 1300 1200 1200 1100 1100 1000 1000 900 900 800 800 700 700 F ir in g T e m p e ra tu re °C Centrifugal Compr. T A T E _TF T G T D _TB S G T -4 0 0

Core Engine Trends: Key Parameter Trends

100 150 200 250 300 350 1975 1980 1985 1990 1995 2000 2005 Year S p e c if ic P o w e r ( k J /k g ) 24 26 28 30 32 34 36 38 40 T h e rm a l E ff ic ie n c y ( % )

Specific Power Output Thermal Efficiency

TB5000

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

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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 Shaft

Expansion through a single series of turbine stages.

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

Twin Shaft

Expansion 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

Compressor

Combustion

system Gas Generator Turbine

Power Turbine

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Environmental Aspects Pollutants 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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Combustion NOx 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 ] N O x F o rm a ti o n R a te [ p p m /m s ] Diffusion Flame Lean Pre-mix

Flame temperature affects thermal NOx formation

Combustion NOx Formation

Rich Lean

Lean burn Diffusion flame reaction

zone temperature F la m e te m p e ra tu re Stoichiometric FAR

Flame Temperature as a function of Air/Fuel ratio

Diffusion flame

Lean Pre-mixed (DLE/DLN)

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Combustor Configuration

NOx 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 Gas Injection Air Main Gas Injection Igniter Gas/Air Mix Gas Pilot Burner Igniter Main 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 conditions

MAIN FLOW CONTROL VALVE MAIN MANIFOLD M BLOCK VALVE BLOCK VALVE BLEED VALVE PILOT FLOW CONTROL VALVE PILOT MANIFOLD MAIN FLOW CONTROL VALVE MAIN MANIFOLD M BLOCK VALVE BLOCK VALVE BLEED VALVE PILOT FLOW CONTROL 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

Combustion

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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

Experience

Stable load accept/reject

Daily variations Load Shed and Accept

kW

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Gas Fuel Flexibility

10 20 30 40 50 60 70

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 operating DLE Capability Under Development Siemens Diffusion Operating Experience BIOMASS & COAL GASIFICATION

Landfill & Sewage Gas

High Hydrogen Refinery Gases

LPG

Off-shore rich gas IPG Ceramics

Off-shore lean Well head gas

Other gas

Associated Gas

CO2 or N2 content of UK Natural Gas

W o b b e M J /m 3 CO2 N2 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

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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 1 5 2 0 25 3 0 3 5 4 0 4 5 5 0 5 5 6 0 6 5 7 0 Wobbe Index MJ/m3 Gasified Biomass Special Diffusion burner Sewage gas standard burner

High Hydrogen gas standard burner

Liquified Petroleum gas modified MPI standard gases UK Natural Gas Landfill gas Special Diffusion burner

Gaseous Fuel Range of Operation

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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

Aerodynamics

High 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.

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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) F re q u e n c y ( H z ) D G Palmer 3-8-01 Iteration 3 version 10 mode 1 mode 2 mode 3 mode 4 mode 5 mode 6 EO3 EO6 EO9 EO10 EO11 EO17 EO18 EO19 EO20 1 0 0 % 9 5 % 1 0 5 %

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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 Designs

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SGT400 First Vane Cooling Features

Impingement Cooling Film Cooling Turbulators Trailing Edge Ejection Cast 2 Vane Segment

First 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.

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Multi-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

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Turbine Validation Process

Design

Analysis

Prototype

_Test

Assess

evaluation 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 3.9MW previously 5.25MWe) Mechanical Drive, 5.7MW (previously 4.9MW) P T HP Rotor blade • SX4 material • Triple fin shroud • Step Tip seal

Compressor Blade

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

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SGT400 PT 2 Nozzle Ring

Industrial Gas Turbines

Advanced Materials & Manufacturing

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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 turbine

Package 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-400

New Package Design

Minimised customer interfaces reducing contract execution/installation costs

1 2 3 4 5 6 7

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

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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. (-57o_C)

•Max. air temp. (+34o_C)

•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 Generation re-emergence of cogeneration BOILER O R DRIER GRID WATER FUEL PRODUCT / STEAM

~

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