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Avery Greg UT Thesis 2016.pdf (2.15 MB)

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A Life Cycle Assessment of Ionic Liquid Pretreatment for Lignocellulosic Biomass

Avery, Greg M
http://orcid.org/0000-0002-6605-0719
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1481273168926691

Abstract Details

2016, Master of Science, University of Toledo, Chemical Engineering.
The goal of this research is to perform a gate-to-gate life cycle assessment (LCA) of an ionic liquid (IL) pretreatment, beginning with the harvested lignocellulosic feedstock poplar and ending with the monosaccharide product glucose. This LCA looks at two different routes for IL incubation and pretreatment: the more traditional high-temperature route (HTR) and low-temperature route (LTR) which consists of a two-step pretreatment with an oxidation step followed by IL incubation. This LCA examines the effects of chemical and energy inputs when determining the environmental impacts for production of one kilogram of the functional unit glucose. Impacts were not allocated to xylose and lignin co-products. The impact categories included in the LCA are Global Warming Potential (GWP), Human Toxicity Potential (HTP), Photochemical Oxidation Creation Potential (POCP), Acidification Potential (AP), and Eutrophication Potential (EP). The effects of recovering and recycling the IL and anti-solvent used in the LTR and HTR pretreatment are also examined. The anti-solvents used in this analysis were ethanol, methanol, and acetonitrile. The recovery methods examined are evaporation and supercritical fluid extraction (SCFE). The combination of LTR, HTR, anti-solvent choice, and recovery method results in a total of twelve scenarios examined in the LCA. Experiments were performed using SCFE to determine the ratio of supercritical carbon dioxide (scCO2) to anti-solvent as a function of recovery of anti-solvent from IL. Energy inputs were estimated for several composite parts of the process: pretreatment, saccharification, and IL/anti-solvent recovery. Recovery steps required the largest portion of total energy input. Thermal and electrical energy inputs and their associated impacts were also defined. The energy inputs for SCFE were derived from chemical process simulation with AspenPlus. Heat integration was used to minimize energy requirements. The LTR was found to produce fewer impacts than the HTR in most scenarios for both chemical and energy inputs. Determining which anti-solvent and recovery method is the most sustainable depends on the impact category chosen for comparison. Acetonitrile requires the least amount of CO2 for recovery with SCFE, and subsequently produces fewer impacts than methanol or ethanol in each impact category when SCFE is used. SCFE has lower impacts in GWP, POCP, and AP than evaporation when acetonitrile is used as the anti-solvent. For this scenario, the least impactful route (LTR or HTR) depends on which impact category is chosen for comparison. Evaporation requires less energy input for recovery compared to SCFE when ethanol or methanol is used as the anti-solvent and more when acetonitrile is used. The scenario that produces the fewest overall impacts is ethanol anti-solvent (followed by methanol anti-solvent), using the LTR and evaporation recovery method. This is true in all impact categories. This is conditional upon recovering ~98% of the IL and anti-solvent from biomass washing during pretreatment, and ~100% with either recovery method.
Constance Schall (Advisor)
Defne Apul (Committee Member)
Sasidhar Varanasi (Committee Member)
176 p.
Chemical Engineering; Engineering; Environmental Engineering

Recommended Citations

Citations

  • Avery, G. M. (2016). A Life Cycle Assessment of Ionic Liquid Pretreatment for Lignocellulosic Biomass [Master's thesis, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1481273168926691

    APA Style (7th edition)

  • Avery, Greg. A Life Cycle Assessment of Ionic Liquid Pretreatment for Lignocellulosic Biomass. 2016. University of Toledo, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1481273168926691.

    MLA Style (8th edition)

  • Avery, Greg. "A Life Cycle Assessment of Ionic Liquid Pretreatment for Lignocellulosic Biomass." Master's thesis, University of Toledo, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1481273168926691

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Toledo and OhioLINK.