1. Gas Turbine Combustion Systems

2. About me
2007-Present Solar Turbines Inc., Caterpillar Company
Ph.D. Combustion Science, MAE, UCSD
General Electric Global Research Center
M.S., Aerospace Engineering, Indian Institute of Technology & University of Stuttgart

3. Motivation to study about Industrial Gas Turbines
What does combustor do?
Types of combustors
Design requirements
Introduction to combustion chemistry
Alternative fuels, pollutants, oscillations
Challenges related with variable load conditions

4. Energy Outlook Report
US DOE

5. Trend of world’s energy consumption (Data from US Department of Energy)
1 Quadrillion = 1015, 1 BTU = 1.055x103 J
1 Quadrillion BTU = 45M Tons Coal or 1T ft3 Natural Gas or 170M Barrels of crude oil
1 Barrel crude oil = 42 gallon = 6.1 GJ of energy
World’s energy requirement can largely be classified into Electric power, transportation energy

6. Trend of world’s electricity consumption (Data from US Department of Energy)
*Organization of economic cooperation and development
Major sources of electricity production
Fossil fuels: Coal, gasoline, diesel, natural gas and other petroleum products
Alternative sources of energy: Wind turbines, solar panels, hydroelectric, nuclear, geothermal, tidal, and list goes on…
Alternative fuels: Ethanol, bio-diesel, biomass, coke oven gas, syngas, municipal waste, landfill gases, anything rotting…

7. Gas turbines industry is going to stay in business for a long time
There is a very well established energy infrastructure based on fossil fuels in US and across the globe.
The world’s proven fossil fuel reserves and lifetimes
The advantage of alternative fuels is that the existing infrastructure can be used.
Gas turbines industry is going to stay in business for a long time

8. About Solar’s Gas Turbines

9. How does this story relate with Gas Turbines Combustion systems?
“Strictly speaking, energy is not “consumed”, but rather is converted into different forms.”
Various types of engines are used to achieve this objective.
Types of engines
Power generation: Gas Turbines, Steam Turbines, Nuclear, Hydro
Transportation : diesel, gasoline, aircraft engines (based on gas turbine cycles)
Steam turbines are similar to gas turbines but they have different principles of operation. Nuclear power plants use nuclear energy to make steam which rotates the steam turbines.

10. Gas Turbines find their applications in
electric power generation, mechanical drive systems, supply of process heat and compressed air, pump drives for gas or liquid pipelines
jet propulsion, land and sea transport (infancy state)
Industrial turbines or prime movers

11. Solar Turbines Incorporated, a subsidiary of Caterpillar Company is a world leading producer of mid-range (1 MW – 25 MW) industrial gas turbines for use in power generation, natural gas compression, and pumping systems.
There are 12,500+ engines installed in 102 countries
Solar ranks as one of the 50 largest exporters in the United States

12. Our units are used for power generation, gas compression, and mechanical drive applications
Power generation is the production of electrical energy whether for stand-by or base load power applications.
Gas compression applications include gathering (at the well head), transmission (pipeline), re-injection (storage), and pressure boost (compression).
Mechanical drive applications are units sold as prime-movers for non-Solar packaged driven equipment, whether generators, compressors, or pumps

13. Harbor Drive Facility

14. Gas Turbines OEMs

15. Output 1.2 MW
Thermal Eff. 24.5%
Output 4.6 MW
Thermal Eff. 29.9%
Output 7.7 MW
Thermal Eff. 34.8%
Output 11.2 MW
Thermal Eff. 33.9%
Output 15.3 MW
Thermal Eff. 35.7%
Thermal Eff. 39.5%

16. Latest addition…
Output 22.3 MW
Thermal Eff. 40%

17. Two Shaft Turbine Engine
Power Generation
Single Shaft Turbine Engine
Output Shaft Power
3)Expansion (Turbine)
2) Combustion
1) Compression
Two Shaft Turbine Engine
Output Shaft Power
Mechanical Drive

18. Simplistic Gas Turbines working principles
1-2 Isentropic compression (in a compressor)
2-3 Constant pressure heat addition (in a combustor)
3-4 Isentropic expansion (in a turbine)
4-1 Constant pressure heat rejection

19. Power generation for gas fields in Siberia
Petrobras, offshore Brazil, Power generation and crude oil production
Natural gas transmission, Desert environment

20. Solar’s presence in San Diego
two, soon to be three, Titan 130's at UCSD
two Taurus 60's at SDSU
some recuperated Saturns at landfills in San Marcos and Santee
a Saturn genset at the Hotel Del
a Mercury 50 at the VA hospital
two Mercurys at Qualcomm
two Centaur 40s at the Balboa Naval Hospital
a Taurus 60 at the Children's Hospital

21. List of companies and their products

25. Difference between Heavy Duty and Aeroderivative Turbines

26. Evolution of products : Uprates

27. Performance of Gas Turbines is limited by
Component efficiencies
Turbine working temperature
Current state of the art
Pr = 35/1
components = 85-90%
TIT = 1650 K

28. What makes Gas Turbines attractive for Industrial prime movers?
Advantages
Very high power-to-weight ratio, compared to reciprocating engines
Smaller than most reciprocating engines of the same power rating
Fewer moving parts than reciprocating engines
Low operating pressures
High operation speeds
Low lubricating oil cost and consumption
High reliability
Goes for 30-50K hours before first overhaul. Usually runs for 100K-300K hours (10+ years) life cycle
Disadvantages
Cost is much greater than for a similar-sized reciprocating engine since the material must be stronger and more heat resistant. Machining operations are more complex
Usually less efficient than reciprocating engines, especially at idle
Delayed response to changes in power settings
These make GT less suitable for road transport and helicopters

29. Some Basics

30. Gas Turbine components
Inlet system Collects and directs air into the gas turbine. Often, an air cleaner and silencer are part of the inlet system. It is designated for a minimum pressure drop while maximizing clean airflow into the gas turbine.
Compressor Provides compression, and, thus, increases the air density for the combustion process. The higher the compression ratio, the higher the total gas turbine efficiency . Low compressor efficiencies result in high compressor discharge temperatures, therefore, lower gas turbine output power.
Combustor Adds heat energy to the airflow. The output power of the gas turbine is directly proportional to the combustor firing temperature; i.e., the combustor is designed to increase the air temperature up to the material limits of the gas turbine while maintaining a reasonable pressure drop.

31. Gas Producer Turbine Expands the air and absorbs just enough energy from the flow to drive the compressor. The higher the gas producer discharge temperature and pressure, the more energy is available to drive the power turbine, therefore, creating shaft work.
Power Turbine Converts the remaining flow energy from the gas producer into useful shaft output work. The higher the temperature difference across the power turbine, the more shaft output power is available.
Exhaust System Directs exhaust flow away from the gas turbine inlet. Often a silencer is part of the exhaust system. Similar to the inlet system, the exhaust system is designed for minimum pressure losses.

32. What drives Research and Development work in Gas Turbines?
In 1950’s component efficiencies
In 1990’s emissions
In 21st century it is emissions and alternative fuels
Nature of application and location are always the factors

33. Simplistic Gas Turbines working principles
1-2 Isentropic compression (in a compressor); h2-h1 = mCp(T2-T1)
2-3 Constant pressure heat addition (in a combustor); h3-h2 = mCp(T3-T2)
3-4 Isentropic expansion (in a turbine); h3-h4 = mCp(T3-T4)
4-1 Constant pressure heat rejection

34. mFqRcomb
(min+mF)CpTout
minCpTin
Gas Turbine
Shaft power 

35. Consider Centaur and Mercury
Known
P ratio = 10
TIT = 1350 K
Compressor Eff. = 0.86
Turbine Eff. = 0.89
Heat exchanger effectiveness = 0.8
Ambient temperature and pressure, 300 K, 1 bar
Specific heat Cp = kJ/Kg-K
Specific heat ratio  = 1.4
Calculate (a) Compressor outlet temperature (b) Turbine out temperature (c) Compressor work (d) Turbine work (e) back work ratio (f) Efficiency for ideal, actual, and recuperator engine

36. First Law:
Stagnation enthalpy
Compressor work
Turbine work
Heat input
For isentropic process

37. Thermal Efficiency
Net work out

38. Equipment efficiencies3 T 4 2 4’ 2’ 1 S
Process 1-2’ and 3-4’ ideal
Process 1-2 and 3-4 actual

39. Heat exchanger effectiveness
Recuperator 3 T
Heat exchanger effectiveness 5 4 2 4’ 2’ 6 1 S

40. Variation of Cp with temperature