Appendix FTaconite BART AnalysisSOx ControlAvailable and Applicable ReviewReference(s)Revised: June 8, 2006

Reference No.

1SO2Pollution Control TechnologyAvailable? Applicable? MPCA Taconite BART Report MPCA BART Guidance (Attachment 2) Other

2CommentsBasic Principle1 Wet Scrubbing (High Efficiency) Yes Yesx x xAbsorption and reaction using an alkaline reagent to produce a solid compound2 Wet Scrubbing (Low Efficiency) Yes Yesx x xAbsorption and reaction using an alkaline reagent to produce a solid compound3 Wet Walled Electrostatic Precipitator (WWESP) Yes Yesx xExisting fabric filtercontrolSuspended particles are separated from the flue gasstream, attracted to plates, and collected inhoppers4 Dry sorbent injection Yes Yesx x xPulverized lime or limestone is directly injected into the duct upstream of the fabric filter. Drysorption of SO2onto the lime or limestone particle occurs and thesolid particles are collectedwith a fabric filter5 Spray Dryer Absorption (SDA) Yes Yesx xLime slurry is sprayed into an absorption tower where SO2is absorbed by the slurry, formingCaSO3/CaSO46 Alternative Fuels Yes Yesx xNot permitted forother fuels.Use a fuel with lower sulfur content.7 Load Reduction Yes NoxCould reduceproductionThis is a strategy to reduce load on a power plantby reducing the electrical demand throughtefficiency projects.8 Energy Efficiency Projects Yes Yesxdecrease amount of fuel required to make an acceptable product9 Coal Drying Yes YesxRequires availableexcess heat sourceDry coal will increase the as-burned BTU value, andtherefore less fuel is required to beburned. Specific energy efficiency project10 Bio Filters No NoxResearch levelGas stream passes through a packed bed of speciallyengineered biomedia which supports thegrowth of active bacterial species. The pollutantsin the gas stream are biodegraded orbiotransformed into innocuous products, such as carbon dioxide, water, chloride ion in water,sulfate or nitrate ions in water.11CANSOLV Regenerable SO2No NoxResearch levelAn aqueous solution of proprietary diamine capturesSO2from the feed gas in a countercurrentabsorption tower. The rich solvent is regenerated by steam stripping, giving a byproduct ofpure, water saturated SO2gas and lean solvent for recycling to the absorber.12 Pahlman Process No NoxResearch levelGas stream is passed through a filter baghouse in which specially-developed, small-particle,high-surface area metal oxide sorbent have been deployed. Pollutants are removed from thegases by adsorption.13 SOx-NOx-Rox-Box No NoxTechnology has notbeen demonstratedDry sorbent injection upstream of the baghouse forremoval of SOx and ammonia injectionupstream of a zeolitic selective catalytic reduction (SCR) catalyst incorporated in the baghouseto reduce NOx emissions.14 Electron (E-Beam) Process No NoxNo operatingcommercialapplications on coalElectron beam irradiation in the presence of ammonia to initiate chemical conversion of sulfurand nitrogen oxides into components which can be easily collected by conventional methodssuch as an ESP or baghouse.Y:\23\38\131\NMC Process Boilers List of Control Technologies 2006-07-11.xls1 of 2Appendix FReference(s)Revised: June 8, 2006

Reference No.

1SO2Pollution Control TechnologyAvailable? Applicable? MPCA Taconite BART Report MPCA BART Guidance (Attachment 2) Other

2CommentsBasic Principle15 Electrocatalytic Oxidation No NoxSimilar to coldplasma. Will keepwatch for availabilityof this technologyUtilizes a reactor in which SO2, NOx, and mercury are oxidized to nitrogen dioxide(NO2),sulfuric acid, and mercuric oxide respectively using non-thermal plasma.On recent project, the vender was doing final trials on full-scale applications.16 NOXSO No NoCommercial versionof adsorption.Limited experience(proof-of-concepttests).Uses a regenerable sorbent to simultaneously adsorbSO2and NOx from flue gas from coalfired utility and industrial boilers. In the process, the SO2is converted to a saleable sulfur byproduct (liquid SO2, elemental sulfur, or sulfuric acid) and the NOx is converted to nitrogenand oxygen.17 Copper-Oxide No NoxAbsorption andSCR. Experiencelimited to pilot scale.SO2in the flue gas reacts with copper oxide, supported on small spheres of alumina, to formcopper sulfate. Ammonia is injected into the flue gas before the absorption reactor and aselective catalytic reduction-type reaction occursthat reduces the nitric oxides in the flue gas.In the regeneration step, the copper sulfate is reduced in a regenerator with a reducing agent,such as natural gas, producing a concentrated stream of SO2.18 SNOX No NoxEarly commercialdevelopment stageCatalytic reduction of NOx in the presence of ammonia (NH3), followed by catalytic oxidationof SO2to SO3. The exit gas from the SO3converter passes through a novel glass-tubecondenser in which the SO3is hydrated to H2SO4vapor and then condensed to a concentratedliquid sulfuric acid (H2SO4).19 Cold Plasma No NoxResearch level1) This number is for reference only. It does notin any way rank the control technologies.2) a) Air Pollution: Its Origin And Control. Wark,Kenneth; Warner, Cecil F.; and Davis, Wayne T. 1998. Addison Wesley Longman, Inc.b) US EPA Basic Concepts in Environmental Science, Module 6, http://www.epa.gov/eogapti1/module6/index.htmc) New and Emerging Environmental Technologies,http://neet.rti.org/d) ND BART ReportsY:\23\38\131\NMC Process Boilers List of Control Technologies 2006-07-11.xls2 of 2