Submitted to: Energy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/26/2003
Publication Date: 11/1/2005
Citation: Day, D., Evans, R.J., Lee, J.W., Reicosky, D.C. 2005. Economical CO2, SOx and NOx capture from fossil fuel utilization with combined renewable hydrogen production and large scale carbon sequestration. Energy. 30(14):2558-2579. Interpretive Summary: The need for less dependence on imported fossil fuels and the use of renewable fuels requires the development of alternatives such as hydrogen for fuel cells developed from agricultural biomass. Elevated atmospheric carbon dioxide, potential global warming concerns and prospective use of soil as a sink for carbon (C) has attracted interest from farmers and land managers to offset C emissions. A novel pyrolysis process (controlled heating) using agricultural, forestry and waste biomass to produce hydrogen and by-products was evaluated in a pilot demonstration. This project investigated production at a continuous, bench-scale level and produced sufficient material for an initial evaluation of a potentially profitable method to produce bio-energy and simultaneously the bi-product to sequester C in soil. The test runs produced a novel bi-product that is a nitrogen-enriched, slow-release, C-sequestering fertilizer. The method of sequestration uses existing farm fertilizer distribution infrastructure to deliver C that is highly resistant to microbiological decomposition. The physical structure of C material provides framework for building a NPK fertilizer inside the pore structure and creates a physical slow release mechanism of these nutrients. These results are significant to farmers and policy makers in that C sequestration and fertilizer management can be used to enhance environmental quality. This information will assist scientists and engineers in developing renewable fuels from agricultural biomass improved management methods to reduce soil C loss and to improve soil C management. Farmers can develop and utilize new management techniques for enhancing soil C by changing fertility management and tillage intensity to accommodate changing soil properties across a landscape. This information will be of direct benefit to the farmers to enable them to cope with spatial variability and maintain crop production with minimal impact on the environment.
Technical Abstract: The need to move toward less dependence on imported fossil fuels and the use of renewable fuels requires the development of alternatives. One such alternative fuel is hydrogen for fuel cells developed from pyrolysis of agricultural biomass. A novel process uses agricultural, forestry and waste biomass to produce hydrogen through pyrolysis and reforming technologies conducted in a 50 kg/hr pilot demonstration. The objective of this project was to investigate and demonstrate the methods of production at a continuous, bench-scale level and produce sufficient material for an initial evaluation of a potentially profitable method to produce bio-energy and simultaneously sequester carbon (C). The test runs produced a novel bi-product that is a nitrogen-enriched, slow-release, carbon-sequestering fertilizer. Seven kilograms of the material were produced for further plant growth response testing. A pyrolysis temperature profile was discovered that results in a C char with an affinity to capture CO2 through gas phase reaction with mixed nitrogen-carrying nutrient compounds within the pore structures of the carbon char. A bench scale project demonstrated a continuous process fluidized bed agglomerating process. The total amount of CO2 sequestration was managed by controlling particle discharge rates based on density. The method of sequestration uses existing farm fertilizer distribution infrastructure to deliver a carbon that is highly resistant to microbiological decomposition. The physical structure of carbon material provides framework for building a NPK fertilizer inside the pore structure and creates a physical slow release mechanism of these nutrients. The complete process produces three times as much hydrogen as it consumes making it a net energy producer for the affiliated power plant. The patent pending process is also applicable to fossil fuel power plants as it also removes SOx and NOx, does not require energy intensive CO2 separation and operates at ambient temperature and pressure.