An Introduction to Gas Turbines

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An Introduction to Gas Turbines Microturbines
for DE ApplicationsWorld Energy Technologies
Summit10 11 February 2004

• Michael Brown Director
• World Alliance for Decentralized Energy (WADE)
• michael.brown_at_localpower.org

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What is Decentralized Energy (DE)?

• Electricity production at the point of use,
  irrespective of size, fuel or technology

• High efficiency cogeneration / combined heat and
  power (CHP)
• Simultaneous production of useful power and heat
  from single fuel source
• The most efficient use of any fuel
• Based on gas turbines, microturbines, engines,
  steam turbines, etc
• On-site renewable energy
• On-grid and off-grid

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Origins of the Gas Turbine

• Concept envisualised at beginning of 20th Century
• First Industrial Gas Turbine built in 1931 by
  Brown Boveri
• In late 1930s focus shifted to aircraft
  propulsion
• Industrial Gas Turbine development continued
  after World War II
• Robust
• Compact
• Ability to operate on gas fuels
• No external coolant required
• Size range now 1 100 MWe

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The Basic Concept simple cycle
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Typical Cogeneration System
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Typical Industrial Cogeneration System
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Gas Turbine Cogeneration Plant
Solar Turbines
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Gas Turbine Cogeneration Plant
Solar Turbines
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Gas Turbine Cogeneration Plant
Solar Turbines
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Principles for Performance Improvement

• Power output and efficiency can be improved by
• Increasing the Firing Temperature
• Greater effect on power output but required
• New Materials
• Thermal Barrier Coatings
• Cooling of hot section components
• Increasing the Pressure Ratio
• Greater effect on efficiency but required
• New materials
• Improved Aerodynamics

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Required Developments

• Market Pressures for
• Lower Emissions
• Water or Steam Injection
• Dry Low Emissions Combustion
• Fuel Flexibility
• New combustion and fuel systems
• New coatings
• Improved Reliability Availability
• Longer Component Lives
• Intelligent Control Systems
• Condition Monitoring

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Required Developments

• Market Pressures for
• Improved Efficiency
• Improved individual component efficiencies
• Tighter tolerances, improved aerodynamics
• More complicated to manufacture
• Higher Firing Temperatures
• More exotic materials
• Reaching firing temperature limits effectiveness
  of DLE
• Reduced Costs
• Increased Power Density
• Higher firing temperatures new component
  designs
• More compact turbomachinery with lower component
  costs
• More highly loaded components

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The Results of Technology Development

• Improvements in design have led to
• Reduced size
• 13MW gas turbine now needs same package space as
  a 6.5MW gas turbine of 1980
• Improved Efficiencies
• 35 electrical efficiency compared to 30 in 1980
  
• Reduced Emissions
• Single digit NOx possible on natural gas
• Further improvements possible, but incremental

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Future Possibilities

• For step change improvements, move to Complex
  Cycle technologies
• Combined Cycle
• Recuperated
• Intercooled Recuperated
• Integration with high temperature Fuel Cells
• Solid Oxide or Molten Carbonate
• Reheat
• Cheng Cycle
• Wet Cycles
• Humid Air Turbine (HAT) Cycles

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Combined Cycle (Brayton Rankine Cycles)
GAS TURBINE
STEAM TURBINE
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Combined Cycle

• Uses GT exhaust gases to produce steam for Steam
  Turbine generator
• Approximately 40 - 50 additional power
• 13MW gas turbine gives c.18.5MW in CCGT
  configuration
• Approximately 15 - 20 points increase in fuel
  efficiency
• 13MW GT of 35 electrical efficiency gives 50
  efficient CCGT
• Increased Capital Costs
• High pressure HRSG, Steam Turbine etc.
• Increased Space Requirements

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Recuperation and Intercooling

• Recuperation
• Uses exhaust gases to preheat combustion air
• Improves efficiency for same mass flow, but
  slight power reduction
• Intercooling
• Reduces the work required to compress air
• Increases power output for same mass flow but no
  efficiency gains
• When combined with recuperation (ICR), improves
  efficiency too
• Rolls Royce WR21
• Simple Cycle 13MW 35 efficiency
• Recuperated 12MW 40 efficiency
• ICR 15MW 45 efficiency

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Combined Gas Turbine / Fuel Cell Derivatives

• Can integrate gas turbines with High Temperature
  Fuel Cells
• Fuel flexible
• Increases power density of FC
• Offers very high electrical efficiencies
• Concept designs and pilot plant
• 200kW pilot scheme from NKK/JFE, Japan with 2000
  hrs experience
• 300kW plant of 57 efficiency under construction
  in USA
• lt 1MW scheme from Siemens Westinghouse within 2
  -3 years
• 40MW concept based around WR21 ICR Gas Turbine

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Gas Turbine Cogeneration - Selection Criteria
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Heat Recovery Methods

• Direct Heating
• Fluid Heating / Hot Water
• Steam Production
• Absorption Chilling
• Preheated Combustion Air

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Industries using Gas Turbine Cogeneration

• Food Processing
• Pharmaceutical
• Pulp and Paper
• Manufacturing
• Refinery
• Hospitals
• Universities

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Cogeneration Economic Factors

• Need for reliable electric and thermal Energy
• Facility Heat to Electricity Ratio of 21
• Electricity Price to Gas Price Ratio of 21
• Continuous Operation

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Gas Turbine Summary

• Simple Cycle designs are approaching their limits
• Application flexible
• Complex Cycles offer improved efficiencies and
  higher power densities
• More complicated designs
• Danger of becoming application specific
• Optimum component technologies may differ from
  simple cycle designs
• Uncertain market conditions
• Will conditions allow commercialisation of new
  technologies ?

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Microturbines

• Small, high-speed generator power plants, 25
  200 kWe
• One moving part
• Primarily fuelled with natural gas major biogas
  potential
• Relatively low capital, OM costs
• Lower emissions than conventional reciprocating
  engines
• Several applications
• Traditional cogeneration, hospitals etc
• Generation using waste and biofuels
• Backup power
• Remote Power for those with Black Start
  capability
• Peak Shaving.

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Microturbines the Capstone System

• 30-60 kW power output
• Multi-fuel capability
• High cogen efficiency
• Low maintenance
• Low emissions
• 2-to-100 unit multipacking
• lt30 kW to 6 MW
• gt2,500 sold worldwide
• gt5 million operating hours

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Inside the Microturbine
Exhaust
Control panel
MicroTurbine
Air inlets
Fuel supply
0-30 0-60 kW400-480 VAC/DC
User connection bay
Digital power controller
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Deep Inside the Microturbine

• One moving part
• No coolants or lubricants
• Compact and lightweight

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WADE Key Points

• Non-profit organisation created June 2002
• Mission
• To accelerate the deployment of DE systems
  worldwide
• WADE is supported by
• National Cogen/DE organisations including COGEN
  Portugal
• Cogen/DE companies with international interests
• Caterpillar, Capstone, Solar Turbines, FuelCell
  Energy, MTU, Marubeni, Primary Energy, Dalkia,
  Wartsila
• UN agencies
• National governments (eg US, Norway, Canada)

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WADE Network of DE Promotional Organisations
2nd (Amsterdam, 2001)
5th (Beijing, 2004
1
st
(Washington, 2000)
3rd (Delhi, 2002)
WADE Network
4th (Rio, 2003)
In train
WADE Annual International Conferences
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WADE action

• Documenting DE development and barriers
• World Survey of Decentralized Energy 2004
• National DE Surveys China, Brazil
• Promoting worldwide knowledge
• Cogeneration On Site Power Journal of
  international DE industry
• Annual International CHP DE Conferences
  Washington (2000), Amsterdam (2001), Delhi
  (2002), Rio de Janeiro (2003), Beijing (2005).
• Promoting DE with international agencies, eg
  World Bank institutions and UN agencies
• Building international network of DE
  organisations
• Carbon credit development from DE