DEC 7, 2012 Biomass Project Partnership

Transcription

1 DEC 7, 2012 Biomass Project Partnership Part 5 Fuel Yard / Project Website / Regulatory Issues Biomass / Coal Fuel & Boiler Considerations Photo credit: Ferman Milster

2 Fuel Yard UI Main Power Plant on constricted site. Campus and city have grown up around us. No UI-controlled coal or biomass long-term fuel storage. Coal supply located in Muscatine IA, 60-miles away. Regional supply opportunity to other coal boilers? Fuel yard provides facility to blend, size, densify, and store biomass and coal. Business model yet to be developed. Likely opportunity for 3 rd party contracted operation. 2

3 UI Main Power Plant 3

4 4

5 Project Website 5

6 Regulatory Issues Need to discuss if a material is classified as a hazardous waste, what are the implications when burned for energy recovery. 40 CFR 261. Boiler 11 90% sulfur removal 6

7 Biomass/Coal Fuel Comparison Proximate As Received Moisture Ash Volatile Fixed Carbon Btu/lb Sulfur Poplar wood chips 46.78% 1.11% 46.02% 6.08% 4, % Miscanthus grass 9.70% 2.70% 75.54% 12.06% 6, % Reed canary grass 8.91% 7.67% 67.04% 16.38% 7, % Reed canary grass 23.53% 7.16% 5, % Corn Seeds 11.59% 0.83% 78.62% 8.96% 6, % Soy Bean Seeds 12.91% 5.21% 74.42% 7.46% 8, % Cardboard sludge 53.13% 7.52% 2, % Oat Hulls 10.03% 4.62% 72.23% 13.13% 7, % Stoker Coal 13.61% 5.72% 35.01% 45.67% 11, % Washed Bituminous 13.26% 8.39% 36.37% 41.98% 11, % Wood Chips 34.68% 0.46% 57.30% 7.56% 5, % Corn Stover 10.00% 6.18% 7, % Brush 27.24% 18.46% 4, % Sludge 7

8 Biomass/Coal Fuel Comparison Biomass has: Less energy density (Btu/lb) More moisture content. Moisture in fuel must be evaporated in the combustion process, and is not available to produce steam in the boiler (1,061 Btu/lb) More oxygen, compared to coal More volatile content As the fuel heats in the furnace, the volatiles turn to gas and burn quickly Less sulfur content, and sulfur dioxide emissions are greatly reduced Typically produces more ash, for a given amount of energy burned Typically does not have heavy metals (e.g. Hg) in stack emissions and ash 8

9 Fuel Btu/lb Tons for 2020 (assuming all additional renewable energy comes from this one source) Poplar wood chips 4, ,948 Miscanthus grass 6, ,892 Reed canary grass 7,092 98,703 Reed canary grass 5, ,946 Corn Seeds 6, ,618 Soy Bean Seeds 8,910 78,563 Cardboard sludge 2, ,875 Oat Hulls 7,240 96,685 Stoker Coal 11,617 60,257 Washed Bituminous 11,130 62,893 Wood Chips 5, ,081 Corn Stover 7,620 91,864 Brush 4, ,121 Assuming the amount of energy we consume in 2020 is the same as 2010, we will need 1.6 million MMBtu of additional renewable energy to reach our goal of 40% renewable. 9

10 Fuel Energy Density Fuel Density (lbs/ft 3 ) Energy Content (Btu/lb) Energy Density (Btu/ft 3 ) Bituminous Coal 55 11, ,500 Energy Pellets 50 11, ,000 Corn Seeds 45 7, ,000 Switchgrass pellets 50 6, ,000 Paper Sludge 50 3, ,800 Lignin 50 3, ,350 Wood Chips (dry) 12 6,000 72,000 Miscanthus Grass 8 7,600 60,800 Wood Chips (green) 14 4,000 56,000 Energy density has an influence on transportation cost. Typically, the lower the density, the more expensive to transport the fuel, per unit of distance. High volume semi-trailers help mitigate energy density influence. 10

11 Stoker Boiler Fuel burns on traveling grate Boiler capacity limited by: Grate heat release rate (how much burning fuel you can put on the grate) Fuel feeder volumetric capacity Gas burners will assure combustion stability and full boiler capacity 11

12 Boiler 10 Fuel Feeder Limits Feeder Volumetric Flow Required (ft 3 /hr) Biomass Density 15 lbs/ft 3 Biomass HHV (Btu/lb) Percent Biomass 4,000 5,000 6,000 7,000 8,000 0% % % % % % % % % % % Feeder Volumetric Flow Required (ft 3 /hr) Biomass Density 30 lbs/ft 3 Biomass HHV (Btu/lb) Percent Biomass 4,000 5,000 6,000 7,000 8,000 0% % % % % % % % % % % Feeder Volumetric Flow Required (ft 3 /hr) Biomass Density 20 lbs/ft 3 Biomass HHV (Btu/lb) Percent Biomass 4,000 5,000 6,000 7,000 8,000 0% % % % % % % % % % % Feeder Volumetric Flow Required (ft 3 /hr) Biomass Density 40 lbs/ft 3 Biomass HHV (Btu/lb) Percent Biomass 4,000 5,000 6,000 7,000 8,000 0% % % % % % % % % % %

13 Circulating Fluidized Bed Boiler Fuel burns in suspension of circulating material Need ash and limestone, or other inert material, to maintain bed integrity Permit requires 90% removal of potential SO 2 emissions Lower combustion temperature, compared to Stoker (less NO x ) 13