Persistent Link:
http://hdl.handle.net/10150/293419
Title:
The Sustainability of Biofuels Produced from Microalgae
Author:
Canter, Christina Elizabeth
Issue Date:
2013
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Fossil fuels are not sustainable due to their worldwide depletion and greenhouse gas (GHG) emissions. Transportation biofuels produced from microalgae are sustainable if GHG emissions are lower than fossil fuels and the sources for materials used during production are sustainable. Four areas were evaluated to address these concerns. First, a study of peer reviewed life-cycle analyses (LCAs) was performed. The purpose of this evaluation was to determine which processing choices during cultivation have the most impacts. Data from nine authors was converted to similar units, and a new LCA was performed to evaluate the impacts. Overall GHG emissions per kg of algae cultivation ranged from 0.1 - 4.4 kg CO₂ eq. / kg algae, with the most of the emissions coming from fertilizer contributions. The second topic evaluated was the GHG emissions from experimental dewatering technologies. The five experimental technology emissions, for acoustic harvesting, membrane filtration, flocculation, electrocoagulation and flocculation plus belt filtration, were compared to a modeled dissolved air flotation technology and a fossil fuel source. For a functional unit of one MJ of renewable diesel (RD), membrane filtration had the lowest GHG emissions at 40.8 g CO₂(eq)/MJ RD. Dissolved air flotation was the highest scenario at 51.9 g CO₂(eq)/MJ RD. All technologies were lower than gasoline at 90.7 g CO₂(eq)/MJ gasoline. The third topic evaluated was the GHG emissions from the materials used for plant construction. A LCA was performed for the infrastructure materials and compared to results from the fuel-cycle. Plastic from pond liners had the largest contribution to GHG emissions for the baseline case. Increasing productivity and lipid content both decreased infrastructure emissions. The final topic evaluated was the sustainability of nitrogen, phosphorus and potassium used for microalgae growth. Results show that the surplus of world fertilizers cannot sustain large scale algae production in the United States. Technology choices that can recycle nutrients lower the overall requirement. Alternative sources of nutrients, like concentrated animal feeding operations, can provide enough nutrients for large scale production of algae.
Type:
text; Electronic Dissertation
Keywords:
Dewatering Technologies; LCA; Microalgae; Nutrients; Sustainability; Chemical Engineering; Biofuels
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Chemical Engineering
Degree Grantor:
University of Arizona
Advisor:
Blowers, Paul

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleThe Sustainability of Biofuels Produced from Microalgaeen_US
dc.creatorCanter, Christina Elizabethen_US
dc.contributor.authorCanter, Christina Elizabethen_US
dc.date.issued2013-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractFossil fuels are not sustainable due to their worldwide depletion and greenhouse gas (GHG) emissions. Transportation biofuels produced from microalgae are sustainable if GHG emissions are lower than fossil fuels and the sources for materials used during production are sustainable. Four areas were evaluated to address these concerns. First, a study of peer reviewed life-cycle analyses (LCAs) was performed. The purpose of this evaluation was to determine which processing choices during cultivation have the most impacts. Data from nine authors was converted to similar units, and a new LCA was performed to evaluate the impacts. Overall GHG emissions per kg of algae cultivation ranged from 0.1 - 4.4 kg CO₂ eq. / kg algae, with the most of the emissions coming from fertilizer contributions. The second topic evaluated was the GHG emissions from experimental dewatering technologies. The five experimental technology emissions, for acoustic harvesting, membrane filtration, flocculation, electrocoagulation and flocculation plus belt filtration, were compared to a modeled dissolved air flotation technology and a fossil fuel source. For a functional unit of one MJ of renewable diesel (RD), membrane filtration had the lowest GHG emissions at 40.8 g CO₂(eq)/MJ RD. Dissolved air flotation was the highest scenario at 51.9 g CO₂(eq)/MJ RD. All technologies were lower than gasoline at 90.7 g CO₂(eq)/MJ gasoline. The third topic evaluated was the GHG emissions from the materials used for plant construction. A LCA was performed for the infrastructure materials and compared to results from the fuel-cycle. Plastic from pond liners had the largest contribution to GHG emissions for the baseline case. Increasing productivity and lipid content both decreased infrastructure emissions. The final topic evaluated was the sustainability of nitrogen, phosphorus and potassium used for microalgae growth. Results show that the surplus of world fertilizers cannot sustain large scale algae production in the United States. Technology choices that can recycle nutrients lower the overall requirement. Alternative sources of nutrients, like concentrated animal feeding operations, can provide enough nutrients for large scale production of algae.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectDewatering Technologiesen_US
dc.subjectLCAen_US
dc.subjectMicroalgaeen_US
dc.subjectNutrientsen_US
dc.subjectSustainabilityen_US
dc.subjectChemical Engineeringen_US
dc.subjectBiofuelsen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineChemical Engineeringen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorBlowers, Paulen_US
dc.contributor.committeememberOgden, Kimberlyen_US
dc.contributor.committeememberGuzman, Robertoen_US
dc.contributor.committeememberDeymier, Pierreen_US
dc.contributor.committeememberBlowers, Paulen_US
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