Recent Developments in Small Industrial Gas turbines

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1 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 Market developments Page 2 Nov 2010 Energy Sector 1

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. Page 3 Nov 2010 Energy Sector Siemens Industrial gas turbine range Industrial Turbines Utility Turbines SGT5-8000H SGT5-4000F SGT6-5000F Figures in net MW SGT6-8000H 266 SGT5-2000E SGT6-2000E SGT SGT SGT SGT SGT SGT SGT SGT Page 4 Nov 2010 Energy Sector 2

3 Industrial Gas Turbine Product Range Portfolio (MW) SGT-100-1S SGT-100-2S SGT-200-1S SGT SGT-700 SGT-600 SGT-500 SGT-400 SGT-300 SGT-200 SGT SGT-200-2S SGT-300 SGT-400 SGT-500 SGT-600 SGT-700 SGT-800 Page 5 Nov 2010 Energy Sector Industrial Gas Turbine Product applications Power Generation Pumping Compression CHP Comb. Cycle 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 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. Two SGT-400 generating sets operating in cogeneration/ combined cycle for BIEP at BP s Bulwer Island refinery, Australia Page 6 Nov 2010 Energy Sector 3

4 Gas Turbine Refresher Comparison of Gas Turbine and Reciprocating Engine Cycle AIR INTAKE FUEL COMBUSTION EXHAUST COMPRESSION Continuous Intermittent AIR/FUEL INTAKE COMPRESSION COMBUSTION EXHAUST Page 7 Nov 2010 Energy Sector Gas Turbine as Prime Mover Gas Turbine Characteristics 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 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 Page 8 Nov 2010 Energy Sector 4

5 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) Page 9 Nov 2010 Energy Sector Ideal Engine Cycle: Efficiency 1 Simple cycle efficiency = 1 P1 P2 Ideal thermal efficiency ( γ 1) /γ Pressure Ratio Cycle efficiency is therefore only dependant on the cycle pressure ratio. Assumption : Ideal cycle with no component or system losses. Page 10 Nov 2010 Energy Sector 5

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 Page 11 Nov 2010 Energy Sector Energy Cost Savings GT cycle parameter study Shaft Efficiency (%) ºC 1250ºC 1300ºC 1350ºC FIRING TEMPERATURE 1400ºC 1450ºC Shaft Specific Output (kj/kg) Increase Pressure ratio and firing temperatures for higher simple cycle efficiencies Page 12 Nov 2010 Energy Sector PRESSURE RATIO 6

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 Page 13 Nov 2010 Energy Sector 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 Page 14 Nov 2010 Energy Sector 7

8 Core Engine Trends: Key Parameter Trends Pressure Ratio CT Centrifugal Compr. TA TE TF TG TD TB Pressure Ratio Pressure Ratio Firing Temperature Firing Temperature YEAR Year SGT-200 SGT-100 SGT-300 SGT-400 Future Machines Firing Temperature C Page 15 Nov 2010 Energy Sector Engine Trends: Thermal Efficiency Specific Power (kj/kg) TB5000 SGT-200 SGT-400 SGT-100 Specific Power Output Thermal Efficiency Thermal Efficiency (%) Year 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 Page 16 Nov 2010 Energy Sector 8

9 Product Evolution SGT-300 Introduced ,900 kwe 30.5% eff TA Introduced kW 17.6% eff Developed to 1,860kW Page 17 Nov 2010 Energy Sector 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) Page 18 Nov 2010 Energy Sector 9

10 SGT-400 Industrial gas turbine Compressor Combustion system Gas Generator Turbine Power Turbine Page 19 Nov 2010 Energy Sector Combustion 10

11 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 DLE System Smog Hydrocarbons Poisonous DLE System Greenhouse gas Smoke Visible pollution DLE System DLE - Dry Low Emissions Page 21 Nov 2010 Energy Sector 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 Page 22 Nov 2010 Energy Sector 11

12 Combustion NOx Formation NOx Formation Rate [ ppm/ms ] Lean Pre-mix Diffusion Flame Flame Temperature [ K ] Flame temperature affects thermal NOx formation Page 23 Nov 2010 Energy Sector Combustion NOx Formation Flame Temperature as a function of Air/Fuel ratio Lean burn Diffusion flame reaction zone temperature Flame temperature Lean Pre-mixed (DLE/DLN) Diffusion flame Lean Stoichiometric FAR Rich Page 24 Nov 2010 Energy Sector 12

13 Combustor Configuration NOx product is a function of temperature Diffusion Combustion - high primary zone temperature Cooling Dry Low Emissions Combustion -low peak temperature achieved with lean pre-mix combustion Page 25 Nov 2010 Energy Sector DLE Lean Pre-mix Combustor (SGT-100 to SGT-400 configuration) Pilot Burner Igniter Liquid Core Main Burner Radial Swirler Robust design involving no moving parts Fixed swirler vanes Variable fuel metering via pilot and main fuel valves Main Gas Injection Igniter Pilot Gas Injection Air Pre Chamber Gas/Air Mix Gas Air Double Skin Impingement Cooled Combustor Page 26 Nov 2010 Energy Sector 13

14 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 BLOCK VALVE BLOCK VALVE M MAIN FLOW CONTROL VALVE MAIN MANIFOLD BLEED VALVE PILOT MANIFOLD PILOT FLOW CONTROL VALVE Page 27 Nov 2010 Energy Sector Combustion DLE Lean Premix System 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 Page 28 Nov 2010 Energy Sector 14

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 Page 29 Nov 2010 Energy Sector Experience Stable load accept/reject Daily profile for unit running more than 8000hrs DLE operation on liquid fuel. kw Daily variations Load Shed and Accept Page 30 Nov 2010 Energy Sector 15

16 Gas Fuel Flexibility BIOMASS & COAL GASIFICATION High Hydrogen Refinery Gases Other gas Associated Gas 3.5 Landfill & Sewage Gas LPG Off-shore lean Well head gas IPG Ceramics Off-shore rich gas Siemens Diffusion Operating Experience Siemens DLE Units operating DLE Capability Under Development Low Calorific Value (LCV) Medium Calorific Value (MCV) Pipeline Quality NG Normal High Calorific Value (HCV) SIT Ltd. Definition Wobbe Index (MJ/Nm³) Page 31 Nov 2010 Energy Sector The change in WI by the addition of inert species to pipeline quaility gas Wobbe MJ/m UK Natural Gas Medium CV Fuel MCV Range development Definition LCV Burner CO 2 or N 2 content of UK Natural Gas CO2 N2 Page 32 Nov 2010 Energy Sector 16

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 Gasified Biomass Special Diffusion burner Sewage gas standard burner Landfill gas Special Diffusion burner High Hydrogen gas standard burner UK Natural Gas Wobbe Index MJ/m3 standard gases Gaseous Fuel Range of Operation Liquified Petroleum gas modified MPI DLE experience on Natural Gas, Kerosene and Diesel DLE on fuels with high N2 and CO2 content. DLE Associated or Wellhead Gases Page 33 Nov 2010 Energy Sector Turbine 17

18 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 Page 35 Nov 2010 Energy Sector Aerodynamics High Load Turbine Computational Fluid Dynamics (CFD) used to complement experimental testing of advanced components. Page 36 Nov 2010 Energy Sector 18

19 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 Page 37 Nov 2010 Energy Sector Mechanical Design - Improved analysis software (grid and solver) and improved hardware allow traditional postdesign 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. Page 38 Nov 2010 Energy Sector 19

20 Fatigue Life of Rotating Blades Positions of Concern Aerofoil Fillets 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 Root Serration (including skew effects) Page 39 Nov 2010 Energy Sector Mechanical Design - Vibration analysis Campbell Diagram for LPT Blade (Blade only) 6000 EO20 EO19 EO18 mode 6 EO mode 5 Frequency (Hz) mode 4 mode 3 mode 2 95% 100% 105% EO11 EO10 EO9 EO mode 1 EO Iteration 3 version 10 Engine Speed (rpm) D G Palmer Page 40 Nov 2010 Energy Sector 20

21 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. Page 41 Nov 2010 Energy Sector Cooled Blading Designs SGT100 > SGT300 > V2500 Aeroengine Page 42 Nov 2010 Energy Sector 21

22 SGT400 First Vane Cooling Features Impingement Cooling Film Cooling Cast 2 Vane Segment Trailing Edge Ejection Turbulators Page 43 Nov 2010 Energy Sector SGT MW Industrial Gas Turbine 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. Page 44 Nov 2010 Energy Sector 22

23 SGT-300 First Stage Cooled Rotor Blade Ceramic Core forming Cooling Passages SGT300 8MW Industrial Gas Turbine Multi-Pass Cooled First Stage Rotor Blade Page 45 Nov 2010 Energy Sector 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 Page 46 Nov 2010 Energy Sector 23

24 T P Turbine Validation Process Design Analysis Prototype Test Assess evaluation and calibration of methods Page 47 Nov 2010 Energy Sector New technology incorporated into existing engine platforms SGT-100 Product Development New ratings have been released Compressor Blade Stator stages S1& S2 Rotor stages R1 & R2 HP Rotor blade SX4 material Triple fin shroud Step Tip seal Aerodynamic modifications to compressor and turbine. Power generation, 5.4MWe (launch rating 3.9MW previously 5.25MWe) Mechanical Drive, (previously 4.9MW) 5.7MW Page 48 Nov 2010 Energy Sector 24

25 Industrial Gas Turbines Advanced Materials & Manufacturing SGT400 PT 2 Nozzle Ring Page 49 Nov 2010 Energy Sector Bladed Turbine Disc Page 50 Nov 2010 Energy Sector 25

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 Page 51 Nov 2010 Energy Sector 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) Page 52 Nov 2010 Energy Sector 26

27 Typical Compressor Set Page 53 Nov 2010 Energy Sector SGT-400 New Package Design Minimised customer interfaces reducing contract execution/installation costs Combustion Air Intake Enclosure Air Inlet On-Skid Controls Fire & Gas System Interfaces Lub Oil Cooler Enclosure Air Exit 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 Page 54 Nov 2010 Energy Sector

28 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 Page 56 Nov 2010 Energy Sector 28

29 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. (-57 o C) Max. air temp. (+34 o C) Gas composition with Wobbe Index >45MJ/m 3 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 Page 57 Nov 2010 Energy Sector Power Generation re-emergence of cogeneration WATER GRID FUEL BOILER OR DRIER PRODUCT / STEAM Page 58 Nov 2010 Energy Sector ~ 29

30 Thank You Page 59 Nov 2010 Energy Sector 30