Aero-Thermochemical Systems

Aero-thermochemical Systems (280 - 15061)
Study: Bachelor in Energy Engineering
Semester 2/Spring Semester
3rd Year Course/Upper Division

STUDENTS ARE EXPECTED TO HAVE COMPLETED:

Calculus I, II
Physics I, II
Chemical Fundaments of Engineering
Writing and Communication Skills
Programming
Thermal Engineering
Engineering Fluid Mechanics

Competences and Skills that will be Acquired and Learning Results:

The objective of this course is to provide the student a basic understanding of the science and technology of aerothermochemical systems.

Knowledge mastered in this course:
- Conservation equations for chemically reactive systems.
- Thermochemistry.
- Combustion kinetics.
- Knowledge of the main features of homogeneous reactive systems (critical extinction/ignition conditions, thermal and chain branching explosions, etc.).
- Fenomenologycal knowledge of flames.
- Mass energy balance on boilers and HRSG and performance analysis.
- Fossil Fuel-Fired Power Generation.
- Operational consideration on boilers and HRSG design, effects of Boilers and HRSG on plant efficiency.
- Determine the adequate methodology to obtain the required variables in an engineering problem (calculus, experiments, etc.).
- Present results in a rational manner, in terms of the relevant parameters.
- Comprehension of basic terminology to understand technical documentation and specific literature.

Specific capacities:
- Characterization of the composition of a mixture of ideal gases in terms of i) species mass fractions, ii) mole fractions and iii) molar concentrations.
- Determination of the composition of a chemically reacting ideal gas mixture in terms of the equivalence ratio.
- Determination of the adiabatic flame temperature of a chemically reactive mixture using atom-conservation equations and chemical equilibrium conditions for the product gases.
- Determination of reduced reaction mechanisms by sistematic application of the steady state approximation to full detailed mechanism.
- Determination of the critical ignition and extinction conditions for steady combustion in a well-stirred adiabatic reactor.
- Solution of convection problems involving solid-liquid and solid-vapor systems where takes place a change in phase of a fluid.
- Solution of radiation heat transfer problems in the presence of participating media.
- Thermal design of Coal Fired boilers.
- Thermal design of HRSG.

General capabilities:
- Analysis based on scientific principles.
- Multidisciplinar approach (use knowledge from several disciplines: Thermodynamics, Engineering Fluid Mechanics, Thermal Engineering, etc.)
- Capacity to locate and understand basic literature on the subject.

Attitudes:
- Analytical attitude.
- Critical attitude.
- Cooperative attitude.

Description of Contents/Course Description:

1. The science of aerothermochemistry.

- Historical perspective.
- Combustion as a science.
- Current developments.

2. Multicomponent mixtures.

- Composition.
* Mass fractions.
* Molar fractions.
* Concentrations.
- Equations of state for ideal gas mixtures.
* The thermal equation of state.
* The caloric equation of state.

3. Thermochemistry.

- Stoichiometric mixture.
- The equivalence ratio.
* Product composition for complete combustion.
+ Lean combustion.
+ Rich combustion.
- Adiabatic flame temperature.
* Definition.
* Heat of combustion.
- Sample calculations.
* Lean hydrogen-air combustion.
* Lean methane-air combustion.
- Complete vs. incomplete combustion.
* Major vs. minor species.
- Chemical equilibrium in reactive systems.
* The equilibrium constant.
* Dissociation of major species.
* Effect of temperature and pressure.
- Sample calculations.
* Dissociation of air.
* Adiabatic flame temperature and product composition of stoichiometric/rich H2 and HC-air mixtures.

4. Combustion kinetics.

- Chemical kinetics.
* Types of elementary reactions.
* Detailed and short mechanisms.
* One-step irreversible models.
* The limit of large activation energy.
- The steady-state approximation.
- Examples:
* Hydrogen combustion.
* Hydrocarbon combustion.
* Zel'dovich analysis of NO production.

5. Combustion in homogeneous systems

- Conservation equations for chemically reacting systems
* Mass.
* Momentum.
* Species.
* Energy
* The heat release rate.
- Steady combustion in a well-stirred adiabatic reactor.
* The Damköhler number.
* Ignition and extinction: The S-shaped curve.
- Reactor design.

6. Flames.

- Premixed vs. Non-premixed flames.
- Examples:
* Jet diffusion flames.
* Flame/vortex interactions.

7. Power systems and steam generators.

- Transition from science to combustion technology.
- Fossil Fuel-Fired Power Generation (hereogeneous combustion of coal).
- Traditional and advanced burning technologies (IGCC, Chemical looping, Fuel cells, energy penalties of CO2 capture).
- Fundamentals on new process for power production.
- Environmental aspects.
* CO2 capture.
- Steam Generator as a way to reduce CO2 emissions.

8. Boilers and heat recovery steam generators (HRSG).

- Principles of boiler operation.
- Classification of boilers.
* Water tube-boilers.
* Fire/smoke tube boilers.
- Boiler Specifications.
- Fundamentals of boiler heat transfer design.
- Fuel type.
- Boiler slagging and fouling.
- Fuel ash corrosion.
- Definitions used in boiler efficiency calculations.
- Heat absorption and efficiency calculations (Heat fired, steam generator efficiency direct and indirect method ) (off-design example)
- Pseudoadiabatic flame temperature.
- Combine cycle and cogeneration application of HRSG and waste heat boilers.
- Gas turbine HRSGs.
- Flue gas composition, gas pressure, fired and unfired modes.
- Design temperature profile calculations.
- Emission Control in HRSGs.
- Improving the HRSG efficiency.

9. Heat transfer in boilers and HRSGs

- Liquid side:
* Phase equilibrium and dimensional parameters in boiling and condensation.
* Boiling heat transfer.
* Boiling modes (The boiling curve).
* Pool boiling.
* Forced convection boiling (external, internal).
* Special topic on Heat transfer in Fossil Fuel-Fired Power Generation: HEAT TRANSFER IN CONDENSERS: CLOSED FEEDWATER HEATERS, cFWH¿s.
- Gas side:
* Fundamentals.
+ Gas side heat transfer in boilers and HRSGs.
+ Gas radiation (nonluminous).
+ Absorption coefficient and optical thickness.
+ Absorptivity and emissivity.
+ Radiative exchange in a gas filled enclosure.
+ Particle matter radiation (luminous).
* Heat radiation in furnaces, boilers and HRSGs.
+ Heat Radiation models in Furnaces.
The speckled enclosure.
+ Convective heating surfaces in boilers and HRSGs.
Finned and bare tubes.
Convection radiation problems in convective surfaces.

10. Thermal design of boilers and HRSG.

- Coal-fired boilers design.
* Principles of Boiler Operation.
* Major steam-water boiler components.
* Steam Drum and steam water system.
* Furnace thermal design.
* The well-stirred combustion chamber model.
- HRSG boilers design.
* Water tube HRSG boiler design consideration.
* HRSG design issues.
* Thermal design aspects of unfired HRSG.
* Sizing of HRSG¿s.
* Case study.

Learning Activities and Methodology:

Teaching methodology will incluye:

1. Lectures: The students will be provided with lecture notes and recommended bibliography.
2. Problem solving sessions related with the course topics.
3. Homework problems aiming at student self-evaluation.
4. Development and interactive presentation of guided works, including three lab sessions as direct application of theory.

Additionally, collective tutorship could be included in the programme.

Assessment System:
ORDINARY CALL:

- Continuous evaluation (60% of the total grade)

Contents:
- Practical problems covering the topics of the program
- Short theoretical questions
- Test quizzes
- Laboratory reports (attendance to laboratory sessions is compulsory)

- Final exam (40% of the total grade)

Contents:
- Practical problems covering the topics of the program
- Short theoretical questions
- Test quizzes

A minimum mark of 4 in the final exam will be required to pass the subject

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EXTRAORDINARY CALL: 2 options

- Final exam (100 % of the total grade)

or (similar to the ordinary call)

- Continuous evaluation (60% of the total grade) + Final exam (40% of the total grade)

Basic Bibliography:

C. K. Law. Combustion Physics. Cambridge Univ. Press. 2006
F. P. Incropera. Introduction to heat transfer. John Wiley & Sons. 2006
G. F. Hewitt. Process heat transfer. CRC Press. 1994
I. Glassman. Combustion. Academic Press. 1985
K. K. Kuo. Principles of Combustion. John Wiley & Sons. 1986
K. Rayaprolu. Boilers for power and process. CRC. 2009
R. A. Strehlow. Combustion Fundamentals. McGraw-Hill. 1985
S. R. Turns. An Introduction to Combustion. Mc. Graw Hill. 1996
V. Ganapathy. Industrial boilers and heat recovery steam generators: design, applications, and calculations. CRC Press. 2002

Additional Bibliography:

F. A. Williams. Combustion Theory (2nd ed). Benjamin/Cummings. 1985
J. D. Buckmaster & G. S. S. Ludford. Theory of Laminar Flames. Cambridge Univ. Press. 1982
R. C. Flagan & J. H. Seinfeld. Fundamentals of Air Pollution Engineering. Prentice-Hall. 1988
Y.B. Zeldovich, G.I. Barenblatt, V.B. Librovich & G.M. Makhviladze. The Mathematical Theory of Combustion and Explosions. Consultants Bureau. 1985