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Production of Biofuels and Value-Added Chemicals from Oleaginous Biomass

Shirazi, Yaser
http://orcid.org/0000-0003-1037-2142
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1520957615062894

Abstract Details

, Doctor of Philosophy, University of Toledo, Chemical Engineering.
Oleaginous biomass such as oilseeds and microalgae are attractive feedstocks for biofuels and chemicals production due to the presence of energy-dense triglycerides. Pyrolysis is a promising technique that can thermally degrade whole biomass and/or triglycerides to drop-in fuels or fuel precursors. However, low yield of liquid products has remained the major obstacle for commercialization of triglyceride pyrolysis since feedstock price is the most significant component of the cost for fuel production from triglycerides. The current practice of feeding bulk liquids into hot pyrolysis reactors results in excessive decomposition and polymerization due to slow volatilization and long residence time. As such, we designed and built a novel continuous pyrolysis system equipped with an atomizer to introduce micron-sized droplets of oil into hot pyrolysis reactors. This approach facilitates rapid vaporization of the feed such that the subsequent vapor phase degradation is efficient and results in high yields of bio-oil. Further, when the volatilized feedstocks are passed through a heterogeneous catalyst bed, this method enables vapor-phase catalytic reactions with high-selectivity and high-yield (with low coke formation). Besides triglycerides, the pyrolysis system has the ability to process feedstocks containing free fatty acids (e.g. tall oil from wood pulping, waste cooking oils or oils from microalgae) that are generally unsuitable for biodiesel production. Finally, the reactor can be used for synthesis of fatty acid derivatives (e.g. fatty nitriles, fatty esters or alcohols) by introducing additional reactants (e.g. ammonia, methanol or hydrogen) and suitable catalysts. Pyrolysis of soybean oil in the absence of catalyst resulted in bio-oil yields as high as 88% (theoretical yield is approximately 92%) at optimal conditions (Trxn =500 °C and t = 60s) with products consisting of 38% hydrocarbons (22% C5-C12 and 16% >C12), 33% long-chain fatty acids (C16-C18, but primarily oleic acid) and 15% short-chain fatty acids (C6-C12). To promote triglyceride deoxygenation and produce high value aromatics, pyrolysis of soybean oil as well as non-edible oils (such as pennycress, camelina and waste cooking oil) in the presence of zeolite resulted in a yield of nearly 60% liquid products, of which more than 70% was benzene, toluene and xylene (BTX). Regeneration of catalyst allowed prolonger reuse - 12 reaction-regeneration cycles were performed without any measurable loss in catalyst performance. To assess the direct production of fatty acid derivatives, triglyceride feed was allowed to react with ammonia that was co-fed into the reactor. In the presence of V2O5 near-theoretical fatty nitrile yields (84 wt.% relative to the feed mass) were obtained. Energy balance calculations indicate that the one-pot reaction vapor phase reaction requires significantly lower energy than the conventional process that relies on the energy-intense triglyceride hydrolysis. To allow (1) separate recovery of energy-dense lipid pyrolysis products and the lower calorific value bio-oils from the degradation of starch and protein and (2) tailored vapor phase upgrading of the resulting fractions, we implemented a two-stage fractional pyrolysis integrated with vapor phase upgrading on whole microalgae biomass. Chlorella sp. was first pyrolyzed at 320 °C to volatilize and degrade the biomass starch and a majority of the protein. Then, the residual biomass was pyrolyzed again at 450 °C to recover products from lipid decomposition. The volatiles from each fraction were passed through an ex-situ zeolite catalyst which resulted in high yield of BTX and catalyst-free biochar.
Sridhar Viamajala (Committee Chair)
Chemical Engineering

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Citations

  • Shirazi, Y. (n.d.). Production of Biofuels and Value-Added Chemicals from Oleaginous Biomass [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1520957615062894

    APA Style (7th edition)

  • Shirazi, Yaser. Production of Biofuels and Value-Added Chemicals from Oleaginous Biomass. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1520957615062894.

    MLA Style (8th edition)

  • Shirazi, Yaser. "Production of Biofuels and Value-Added Chemicals from Oleaginous Biomass." Doctoral dissertation, University of Toledo. Accessed MAY 04, 2024. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1520957615062894

    Chicago Manual of Style (17th edition)

toledo1520957615062894
653
© , some rights reserved.Creative Commons License Production of Biofuels and Value-Added Chemicals from Oleaginous Biomass by Yaser Shirazi is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Toledo and OhioLINK.