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Unformatted text preview: 1 1 Chemical Engineering 633 Combustion Processes Review 2 Exam 2 Review Classes 16-27 Chapter 5 NOx Chapter 15 Pollutant Emissions Chapter 6 Canonical Reactors Batch, PFR, PSR Chapter 7 Governing Equations Shvab-Zeldovich Conserved Scalars Chapter 8 Premixed Flames Premixed Analysis Flame Speed Extinction/Ignition 2 Reading: Chps 5-8, 15 Homework assignments 5-7 Class discussions 2 Class 16NO x Chemistry Three Mechanisms Thermal Prompt (includes fuel) N 2 O intermediate Regions of activity Zeldovich Mechanism (O2, N2 NO) Effects, limits: T, [O] eq . Prompt: Fuel frag + N2 HCN NO NO Control: combustion and post-combustion controls NO vs T, NO vs , timescale SCR, SNCR, explicity remove N 2 from feed (air separation, etc.) Quantities Fuel NO x = half of total Limits: 15-40 ppmv 3 Class 17Pollutant Emissions Emissions measures, CO, HC, SO x Emission Index = mass emit / mass fuel Concentration (ppmv) Dry or wet basis: convert between Corrected concetrations (given O 2 basis) SO x From S in fuel: Coal, Diesel, (gasoline) All S is converted to SO x , unlike NO x . Limestone or lime scrubbing: CaCO 3 , CaO hydrated CaSO 3 . Wet or dry spray towers Ash/soot Baghouse Unburnt HC/CO Run lean, post combustion (3-way catalyst) Engines: wall quenching/oil absorption....
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- Winter '12
- Chemical Engineering