Theses and Dissertations

Bidhya Kunwar

Issuing Body

Mississippi State University

Advisor

Mlsna, Todd E.

Committee Member

Wipf, David.

Committee Member

Zhang, Dongmao.

Committee Member

Yu, Fei.

Committee Member

Emerson, Joseph P.

Date of Degree

5-17-2014

Document Type

Dissertation - Open Access

Major

Chemistry

Degree Name

Doctor of Philosophy

College

College of Arts and Sciences

Department

Department of Chemistry

Abstract

The focus of my research was the exploration of the conversion of biomass to an alternative liquid fuels. One focus was on online monitoring for the optimization of biomass gasification to improve the production of synthesis gas. To accomplish this goal, required development, assembly and testing of an instrument to monitor synthesis gas production from biomass gasification. Requirements for simplicity and the ability to separate complex mixtures of analytes to aid in their identification led to the development of a low cost, autosampling, portable gas chromatograph for the continuous online monitoring of biomass gasification during the production of synthesis gas (primarily CO and H2). Design features, calibration, and results of pilot scale testing are presented herein. Another research focus is upgrading pyrolysis bio-oil by hydrodeoxygenation (HDO), water gas shift (WGS) and acid catalyzed reactions in the presence of synthesis gas. We have prepared a series of HDO catalysts containing cobalt, nickel and molybdenum as the active metal sites using ZSM-5 as a base support. A copper based commercial catalyst was used to promote the WGS reaction. The two acid catalysts used are Dowex and Silica sulfuric acid. A treatment of raw bio-oil at elevated temperatures and pressures in the presence of catalysts and alcohol with WGS and HDO or octene with an acid catalyst showed marked improvements in important properties including acid value, HHV value, and percent water. The upgraded bio-oils were analyzed using GCMS, IR and NMR while SEM, EDS and AAS techniques were used for the catalyst characterization. Another part of this research is to utilize biochar produced during biomass gasification and pyrolysis for metal adsorption from water. Biochar ground to 0.5-2 mm obtained from pyrolysis and gasification of pine woodchips and pyrolysis of switch grass were used for the removal of Pb(II) and Cr (VI) from aqueous solution. The effect of pH, temperature, equilibration time, adsorbent and adsorbate doses in metal sorption was studied. The degree of metal adsorption was analyzed by AAS. By optimizing pH, temperature, equilibration time, and adsorbent concentration the adsorption of Pb(II) was increase to 95% and Cr(VI) was increased to 25%.

URI

https://hdl.handle.net/11668/16594

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