Degree Type

Thesis

Date of Award

2008

Degree Name

Master of Science

Department

Agricultural and Biosystems Engineering

First Advisor

Robert P. Anex

Second Advisor

Raj Raman

Third Advisor

Matt Liebman

Abstract

Relative to fossil fuels, biofuels help to close the carbon cycle; however other essential nutrient cycles remain open. When biomass is removed from the agricultural landscape for biofuel production, essential plant nutrients such as nitrogen (N), phosphorus (P), and potassium (K) are also removed and concentrate in biorefinery waste streams and low value co-products. This thesis comprises three analyses related to nutrient cycles in the emerging bioeconomy. In the first, combusted biomass ash was pelleted and evaluated as a potential fertilizer. In the second, an energy co-product credit for corn dry grind ethanol production has been determined by examining the effect of variable inclusion rates of distillers grains (DG) in cattle diets. In the third analysis, the net energy and spatial concentration of nutrients and water consumption have been determined for an integrated beef-ethanol production system that benefits from recovering energy from co-product streams and co-locating complementary unit processes.

DOI

https://doi.org/10.31274/rtd-180813-16560

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Katherine A. Edwards

Language

en

Proquest ID

AAI1453145

OCLC Number

237054388

ISBN

9780549542155

File Format

application/pdf

File Size

79 pages

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