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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

Separation and purification of valuable chemicals from simulated hydrothermal conversion product solution

Liu, Fang January 2012 (has links)
5-HMF as a versatile organic compound is considered as a promising biomass-derived value-added product via dehydration of saccharide. A large amount of research has been carried out on its production and separation. In this research, three single and three mixed solvents were tested to separate 5-HMF via liquid-liquid extraction from simulated HTC products. The mixed solvents were made up of DCM-THF, DCM-2-butanol and 2-butanol-THF with different mixing ratio of 1:4, 1:1, and 4:1. 20wt% and 10wt% NaCl were added in to help phase separation and to improve the performance of extraction. The simulated HTC product was composed of 5-HMF, levulinic acid and furfural. The extraction was carried out in vial and the phase separation was accomplished in a separatory funnel. The aqueous phase was analyzed with HPLC-UV to determine the solute concentrations in the aqueous phase. The solute concentrations in organic phase, partition coefficients, separation factors, solute recovery rates and purities of 5-HMF in separated products were calculated accordingly. The separation performance of mixed solvents was compared with theoretical values. In addition, the effects of pH and NaCl concentration on extraction and separation were investigated. It was found that the partition coefficients of 5-HMF were always higher than those of levulinic acid. 20 wt% of NaCl improved 5-HMF extraction significantly, and the corresponding partition coefficient was 6.87. Extraction of levulinic acid was found more sensitive to solvent pH value than 5-HMF and furfural. For 5-HMF extraction, pH 2.4 was more favorable than pH 2.0. Meanwhile, mixed solvents had better extraction performance than each single solvent for 5-HMF. The performance of the mixed solvents depended on mixing ratio; partition coefficient showed linear correlation with mixing fraction. More furfural was extracted into organic phase than 5-HMF, and the partition coefficients of levulinic acid were very close to that of 5-HMF. In general, however, mixed solvent extraction was able to improve the extraction efficiency rather than separation efficiency of 5-HMF.
192

Biomass and coal fly ash in concrete : strength, durability, microstructure, quantitative kinetics of pozzolanic reaction and alkali silica reaction investigations /

Wang, Shuangzhen, January 2007 (has links) (PDF)
Thesis (Ph. D.)--Brigham Young University. Dept. of Chemical Engineering, 2007. / Includes bibliographical references (p. 161-168).
193

Fermentative hydrogen production from wastewater by immobilized biomass

Li, Difu, January 2007 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available in print.
194

Renewable liquid fuels from catalytic reforming of biomass-derived oxygenated hydrocarbons /

Barrett, Christopher J., January 2008 (has links)
Thesis (Ph.D.)-- University of Wisconsin--Madison, 2008. / Includes bibliographical references (p. 138-144). Also available on the Internet.
195

The production of liquid fuels and chemicals from biomass derived polyols by catalytic coupling /

Simonetti, Dante Adam. January 2008 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 2008. / Includes bibliographical references. Also available on the Internet.
196

Carbon mitigation with biomass an engineering, economic and policy assessment of opportunities and implications /

Rhodes, James S. January 1900 (has links)
Thesis (Ph. D.)--Carnegie Mellon University, 2007. / Adviser: Keith, David W. Includes bibliographical references.
197

Chemical characterization in the biorefinery of lignocellulose : formation and management of oxalic acid and analysis of feedstocks for bioethanol production /

Sjöde, Anders, January 2008 (has links)
Diss. (sammanfattning) Karlstad : Karlstads universitet, 2008. / Härtill 6 uppsatser.
198

Testing two applications of image analysis for use in species-independent biomass equations for western Oregon forests /

Gray, John Edward, January 1998 (has links)
Thesis (M.S.)--Oregon State University, 1999. / Typescript (photocopy). Includes bibliographical references (leaves 34-37). Also available on the World Wide Web.
199

Effects of deforestation and land use on biomass, carbon, and nutrient pools in the Los Tuxtlas Region, Mexico /

Hughes, R. Flint. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 1998. / Typescript (photocopy). Includes bibliographical references (leaves 99-107). Also available on the World Wide Web.
200

A case study approach for assessing operational and silvicultural performance of whole-tree biomass harvesting in Maine /

Coup, Charles E., January 2009 (has links)
Thesis (M.S.) in Forest Resources--University of Maine, 2009. / Includes vita. Includes bibliographical references (leaves 133-144).

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