Conservation of Feedstock Nutrients in Pyrolysis Biochars Jatara Wise, PhD

Benefits of Bio-char Sequester C in soil Increase Ca, Mg, P, and K Increase Fertilizer efficiency Decrease Al toxicity Increase Soil Water holding capacity Decrease Nitrous oxide emissions Reduce bulk density: Soil Dependent

Terra Preta Oxisol

Pyrolysis Reactors Fixed-bed (Auger-fed)Fluidized-bed Source: Boateng et al, 2007

Slow Pyrolysis system layout

Why Nutrient Conservation? Give bio-char a value in fertilizer terms Improve soil conditions and crop production Sustainable conversion platform

Research Objective and Hypotheses Objective Evaluate the conservation of feedstock nutrients, mass, and energy in co- products among feestocks using two different reactor designs. Hypotheses H 0 : The conservation of nutrients, on a feedstock basis, does not depend on feedstock, pyrolysis conditions, or reactor design. H a : There is some dependence.

Experimental Design Fixed-bed, slow pyrolysis 4 Feedstocks –Corn stover, Rice biomass, Switchgrass, and HES 2 Temperatures –500 C, 600C 2 Flow rates –1 Lpm, 2 Lpm → 4x2x2 Split-Split Factorial Design →Focused on feedstock Fluidized-bed, fast pyrolysis 3 Feedstocks –Corn, Switchgrass, and HES 1Temperature 1 Flow rate

Fixed-bed, Slow Pyrolysis SpeciesPStd DevK CaStd DevMgStd Dev % Bio-char co-product Corn stover49.9c † a a b26.1 Switchgrass159.8a c a a20.1 HES90.5b d a c12.2 Rice stover52.1c b b c2.5 Conservation of bio-char nutrients † P=0.05

Fluidized-bed, Fast Pyrolysis SpeciesPStd DevK CaStd DevMgStd Dev % Bio-char co-product (Wyndmoor, PA) Corn stover65.4a † a a a3.0 HES56.5a a a b5.3 Switchgrass30.1b6.78.9b b c1.4 Conservation in bio-char and bio-oil † P=0.05

Conclusions 1.Feedstock dependence –Switchgrass is different from HES, Corn stover, Rice Biomass 2.Reactor design dependence –Hence, conservation cannot be simply and arbitrarily assumed for a given feedstock or reactor design 3.Correlation to feedstock fiber properties (cellulose, hemicellulose, sugars, lignin) –Correlation analysis, MLR 4.Reactor design and construction may contaminate pyrolysis biochar resulting in elevated (>100%) conservations of select nutrients –Release of metal contaminants from tubing –Needs further investigation 5.Low conservation of feedstock K (both reactor designs) –Consistent with literature –Vaporization losses (Gaskin et al., 2007) –KCl and K 2 SO 4 at temperatures above 500°C (Boman, 2005) 6.More complex thermo-chemical reactions –Inside reactor (labile fraction)

Acknowledgements Committee members –Don Vietor, PhD (Co-chair) –Tony Provin, PhD (Co-chair) –Sergio Capareda, PhD (member) –Clyde Munster, PhD (member) Funding Sources –USDA National Needs Fellowship –Sloan Fellowship –Hispanic Leaders in Agriculture and the Environment (HLAE) –Sun Grant North Central Region Group Members –Matt Keough –Derek Husmoen –Ronnie Schnell –Bill Allen