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Published byTalia Chisenhall Modified over 10 years ago
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Co-firing Coal and Oat Hulls at the University of Minnesota VIII International Oat Conference June 28 – July 2, 2008 Minneapolis, MN Your logo here
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VIII International Oat ConferenceJune 28 – July 2, 2008 Foster Wheeler Twin Cities, Inc. University of Minnesota Management, Operation and Maintenance Agreement (MOMA) - July 1992 Construction Agreement - July 1992 New Package Boilers, FW CCFB and Turbine Generator at UM SE Plant Completed - 2000 Cost Reimbursable Contract (MOMA II) - May 2004 Fixed Fee Performance Fee
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VIII International Oat ConferenceJune 28 – July 2, 2008 University of Minnesota - SE Heating Plant Steam Source for Minneapolis Campus (On Mississippi River at St. Anthony Falls)
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VIII International Oat ConferenceJune 28 – July 2, 2008 National Register of Historic Places Twin City Rapid Transit Company Steam Power Plant -1903
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VIII International Oat ConferenceJune 28 – July 2, 2008 University of Minnesota Foster Wheeler Compact Circulating Fluidized Bed FW CCFB 200,000 lbs/hr 930 psig, 900 o F 15 tons/hr, 8,750 Btu/lb subbituminous coal Boiler and baghouse inside building
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VIII International Oat ConferenceJune 28 – July 2, 2008 University of Minnesota Reasons for Biomass Utilization Minnesota Pollution Control Agency Permit limits annual coal and oil use to 30% of fuel mix on a Btu basis. Balance of permitted fuel mix is natural gas, wood and oat hulls. Wood and oat hulls are less expensive than natural gas. University is a member of the Chicago Climate Exchange and is committed to reduction in net CO 2 emissions.
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VIII International Oat ConferenceJune 28 – July 2, 2008 Limitations on Biomass Utilization University biomass limited by permit to wood and oat hulls. New types of biomass require a permit amendment which may take years to obtain. Contractual commitments from biomass suppliers difficult to obtain due to competition for materials. Biomass utilization has major material handling issues. University solid fuel systems not designed to handle wood and oat hulls.
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VIII International Oat ConferenceJune 28 – July 2, 2008 University of Minnesota Biomass Utilization Issues Acquisition and Accounting Material properties affecting transporting, flow and combustion Dust control Spontaneous combustion Odor issues
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VIII International Oat ConferenceJune 28 – July 2, 2008 Acquisition and Accounting Issues Scheduling coordination with coal deliveries. Coal delivered by rail (20 – 30 railcars) Oat hulls by truck, 50 - 60 trucks for each coal delivery Limited storage for coal and oat hulls Accurate fuel inventory is difficult. Large numbers of trucks due to low bulk density (100s of weigh tickets)
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VIII International Oat ConferenceJune 28 – July 2, 2008 Biomass and Mixed Fuel Bulk Densities (UM solid fuel systems designed for volumetric flow) Material Properties ProductBulk Density (lbs/cu. ft.) Oat Hulls (compaction varies)11 – 21 Oat Hull Pellets36 Wood12 Coal/Oat Hull Mix20 – 40 Subbituminous Coal54
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VIII International Oat ConferenceJune 28 – July 2, 2008 Coal and Oat Hull Fuel Analysis (Concern is Chlorine due to HAPs Emission Limits) HAPs = Hazardous Air Pollutants Coal and Oat Hull Fuel Analysis (Concern is Chlorine due to HAPs Emission Limits) HAPs = Hazardous Air Pollutants Fuel Analysis: Subbituminous Coal and Oat Hulls Property (as received)Subbituminous CoalOat Hulls Moisture %27.498.78 Carbon %51.3542.49 Hydrogen %2.94.66 Nitrogen %0.680.83 Sulfur %0.230.12 Ash %4.795.19 Oxygen %12.5637.93 Chlorine %<0.010.1 HHV (Btu/lb)8,7487,091
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VIII International Oat ConferenceJune 28 – July 2, 2008 Primary Form of Oat Hulls Delivered to University
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VIII International Oat ConferenceJune 28 – July 2, 2008 Alternate Form of Oat Hulls Delivered to UM
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VIII International Oat ConferenceJune 28 – July 2, 2008 Oat Hull Pellets (Delivered by Rail from Canada)
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VIII International Oat ConferenceJune 28 – July 2, 2008 Oat Hull Pellets After Outside Storage
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VIII International Oat ConferenceJune 28 – July 2, 2008 University Coal Unloading and Storage Building (All solid fuel delivered to this site)
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VIII International Oat ConferenceJune 28 – July 2, 2008 University of Minnesota Coal Storage Building (Coal depth 12 feet where person is standing)
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VIII International Oat ConferenceJune 28 – July 2, 2008 Unloading Oat Hulls (All deliveries using walking floor trucks)
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VIII International Oat ConferenceJune 28 – July 2, 2008 Mixing Coal and Oat Hulls (Mixing two volumes of oat hulls to one of coal)
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VIII International Oat ConferenceJune 28 – July 2, 2008 Mixing Coal and Oat Hulls (note oat hull dust)
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VIII International Oat ConferenceJune 28 – July 2, 2008 Mixing Coal and Oat Hulls
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VIII International Oat ConferenceJune 28 – July 2, 2008 University of Minnesota Tunnel Conveying (Note dust hood near top of picture and sprinkler heads)
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VIII International Oat ConferenceJune 28 – July 2, 2008 University of Minnesota SE Plant Storage Bunker (Telescoping chute for dust control)
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VIII International Oat ConferenceJune 28 – July 2, 2008 University of Minnesota SE Plant Coal Storage Bunker (30% Oat Hull, 70% Coal Mix)
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VIII International Oat ConferenceJune 28 – July 2, 2008 University of Minnesota SE Plant Bunker Temperature 6 Inches Below Surface (white material is snow, odor of material present)
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VIII International Oat ConferenceJune 28 – July 2, 2008 University of Minnesota SE Plant Bunker after Heavy Snowfall (snow melted off surface from heat in bunker) (odor of decomposing oat hulls present)
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VIII International Oat ConferenceJune 28 – July 2, 2008 Modes of University CCFB Boiler Operation Boiler base loaded with mix of coal/oat hulls/wood Boiler load following on gas with fixed amount of coal/oat hulls/wood Boiler load following on gas with fixed amount of oat hull pellets
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VIII International Oat ConferenceJune 28 – July 2, 2008 Fuel Mixture Effect on University CCFB Boiler Operation Rat-holing constant problem in CCFB silos Spontaneous combustion in silo wall buildup Reduction in NOx Emissions (> 15%) Flyash reinjection problems reduced due to a lower density flyash
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VIII International Oat ConferenceJune 28 – July 2, 2008 Effect on University of Minnesota CCFB Boiler Operation (boiler slag formations due to coal/oat/wood mixture)
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