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CEE 452/652

Review for Final

Dr. Dave DuBoisDivision of Atmospheric Sciences,

Desert Research Institute

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Ch 1: Intro. & Legislation

• Composition of the atmosphere• Troposphere (focus of this course), bottom layer

of atmosphere• What are pollutants?• NAAQS, criteria pollutants• Scales of pollutants, sources of pollutants• Legislation, Clean Air Act, Titles• New Source Review permitting• Prevention of Significant Deterioration

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Ch 1: Intro. & Legislation

• Ideal gas law• Conversions between concentration units• Effects of pollutants: PM10, PM2.5, SO2,

NO2, CO, Pb, VOCs– Health, Biological, Welfare

• Trends of pollutants and emissions• Effects of averaging time in sampling

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Ch 2: Process Design

• Process design• Material balances• Economics- scaling costs

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General Control• Basic characteristics

– Controls which pollutant or pollutants– What are the emission standards?– Fundamental process behind device– Control system capacity– Control efficiency– What is the effluent after the control device?– Pressure drop– Limitations– Cost

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Ch 3: Particle Characteristics

• Particle Size Distribution• Representative size• Log-normal• Relaxation time/stopping distance• Settling velocity• Aerodynamic diameter• Settling chamber design

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Ch 4: Cyclones• Mechanism• Collection efficiency• Size cut• Effective size range of collection• Pressure drop• Standard designs• Cost

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Ch 5: Electrostatic Precipitators

• Types of ESP• Charging mechanisms• Electrical mobility• Drift velocity• Deutsch Equation• Resistivity• Arrangement and design of plates

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Ch 6: Baghouses

• Types– Reverse air– Shaker– Pulse-jet

• Collection efficiency• Fabric materials• Pressure drop• Usage in hot mix asphalt plants

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Ch10: Properties Gases

• Properties of gases and vapors• Diffusion and equilibrium• Solubility• Adsorption• Chemical reactions• kinetics

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Ch 11: VOC Incinerators

• Incinerators for VOC removal• Three T’s• Catalytic oxydation• Thermal oxydizers• flares

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Ch 12: Adsorption

• Adsorption• What is adsorption?• Physical and chemical adsorption• Types of adsorption substrates (absorbents)

– Silica gel, activated carbon– Zeolites and molecular sieves

• Surface area important• Measures of absorptive capacity• Breakthrough curve

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Ch 12: Adsorption

• Types of adsorption control devices– Fixed bed systems– Moving bed systems– Fluidized bed systems

• Regeneration• Pressure drop across bed• Min/max be depth

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Ch 13: Absorption

• Absorption• What is absorption?• Mass transport from gas to liquid: Henry’s law• Types of systems

– Packed bed (vertical tower and cross flow scrubbers)– Spray tower– Tray tower– Venturi– Ejector– Biofiltration

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Ch 13: Absorption

• Packing elements• Surface area and gas velocity important in

design• Calculate tower area and diameter for

packed tower absorber

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Ch 14: Odor Control

• Control of Odors• Physical controls

– covers• Biological control of VOCs

– Aerobic and anaerobic

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Ch 18: Mobile Sources

• Mobile sources• What are mobile sources?• Engines: 4- vs 2-stroke designs vs diesel• Add-on controls• Operational controls• Controls through fuel design• Controls through emission testing (I/M)

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Ch 19: Meteorology

• Air Pollution Meteorology• Causes of wind flow and how it is modified by

physical barriers• Use of power law to calculate wind speed vs

height• Slope and valley flows, sea/land breeze• Urban heat island effects• Wind roses• Temperature structure, buoyancy and stability• Temperature inversions• Visibility• Light extinction process

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Ch 19: Meteorology

• Meteorological Measurements• How to measure mixing height and

stability? What instruments are used?• Remote vs in-situ sampling

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Ch 20: Dispersion Models

• Dispersion modeling• Eulerian vs Lagrangian• Steady state vs instantaneous• Box model approach for steady state Eulerian• Gaussian approach for steady state Lagrangian

– Empirically derived dispersion coefficients– Models concentrations from stack emissions– Plume rise– Stack design

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Ch 20: Additional Topics

• Photochemistry and urban air quality• Formation of O3, OH, NO2• Difference between reactive and

nonreactive VOCs in photochemistry• Importance of secondary production of

pollutants from primary• Reaction time, residence time, transport• Differences between urban and rural

chemistry

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Additional Topics

• Emission inventories• Emission rate calculations with control

efficiencies• AP-42 emission factors• Accounting for point, mobile, area and

biogenic categories

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Ch 16: NOx Control• NOx formation

– Thermal NOx– Fuel NOx

• Operating control techniques– OSC– FGR– Gas reburning– Lo-NOx burner

• Flue Gas Controls– SCR & SNR– SCONOX– Dry and wet sorption

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Gas Combustion Turbines• Basic elements

– Compressor– Combustor– Power turbine

• Categories– Simple cycle– Combined cycle– Regenerative– Cogenerative