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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.
1

Biomass to Biofuel: Catalysis, Monitoring, and Utilization of Biochar

Kunwar, Bidhya 17 May 2014 (has links)
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%.
2

Field Disease Incidence, Fungal Collection, and Evaluation of Koch's Postulates with Isolated Fungi from Giant Miscanthus (Miscanthus X Giganteus) in Mississippi

Gilley, Maxwell Daniel 17 August 2013 (has links)
The establishment of perennial grasses as biomass crops has increased the production acreage of giant miscanthus (Miscanthus x gigantues Greef et Deu, MXG). Yield loss and establishment failure could be detrimental to the sustainable production of this crop, and therefore, exploitation of differentiation in cultivar response to fungal diseases could be a key management strategy. A study was initiated in 2010 to evaluate MXG cultivars for foliar disease incidence (FDI) and compare to switchgrass (Panicum virgatum L., SG) cultivars, isolate and identify fungi from symptomatic leaf material, and demonstrate through Koch’s postulates the ability of these fungi to incite symptoms observed in the field. Giant miscanthus FDI ratings were similar between MXG cultivars, but significantly lower when compared to SG cultivars. Thirty genera of fungi were identified from fungal collections, and 16 pathogenic genera were isolated. Twelve isolates were selected and four were demonstrated to be pathogenic on Mxg.
3

Algae Lysis with Pulsed Electric Fields

Foltz, Garrett 01 May 2012 (has links)
With growing interest in alternative fuels, algae lipid harvesting is seen as a possible source of biofuel. Algae species under consideration include Chlorella vulgaris, Chlamydomonas reinhardtii and Dunaliella salina due to lipid contents as high as 30% to 56% of their dry weight (depending on growth conditions) and availability [5], [6]. In order to harvest lipids from algae, the cells must first be lysed. Lysing is achieved by breaking the algal cell wall or membrane to separate oil from the rest of the algae biomass. Current lysing procedures use enzymes, pressure homogenization, and/or sonication to lyse cells; however, these methods are costly and complicate oil extraction [9], [10]. This project examines a novel method of cell lysis through pulsed electric field (PEF) application that enables cost-effective extraction methods relative to current enzyme and sonication techniques. A theoretical model for cell membrane potential in the presence of electric field was developed, and PEF chambers were manufactured on microscope slides to enable microscope viewing and cell lysis recording during PEF application. Additionally, larger static chambers were created for testing higher volumes of algal solution. Electric field characteristics, such as pulse width, pulse number and magnitude, sufficient for lysis of Dunaliella salina and Chlorella vulgaris were found.
4

Algal biofuels : the effect of salinity and pH on growth and lipid content of algae

Gutierrez, Cesar Carlos 2009 August 1900 (has links)
Supplies of nonrenewable fossil fuels are becoming more limited even as they continue to contribute to pollution and economic concerns. Alternative sources of energy must be developed that help minimize these problems. One potential source of energy is the production of biofuels from algae. Here we evaluate algae found in South Texas brackish water ponds used for aquaculture of fish as a possible source of biofuels. In particular, we examine the effects of salinity and pH on the growth and lipid content of the algae. Samples of algae from the ponds exhibited high levels of growth and lipid production at a salinity of 9 ppt and pH 7. These conditions are similar to the natural conditions of the ponds, indicating that they may be a good source of algal biofuels. / text
5

Growing crops for biofuel and forage while conserving soil and water

Evers, Byron J. January 1900 (has links)
Master of Science / Department of Agronomy / Humberto Blanco / The use of renewable feedstocks to produce cellulosic ethanol is quickly becoming a reality as facilities to produce cellulosic ethanol are scheduled to open in the upcoming years. Initial feedstocks for these facilities are thought to be crop residues such as corn (Zea mays L.) and wheat (Triticum aestivum L.) residues. However, additional feedstocks, such as perennial warm-season grasses (WSG), maybe needed to meet the demands of these bioenergy facilities. Thus, the development of regional dedicated energy crop systems is a high priority. Our objectives were to: a) assess the impacts of growing WSG on water storage, soil physical and hydraulic properties, soil organic carbon (SOC) dynamics, and water and wind erosion as compared with row crops, b) assess the impacts of growing WSG on biomass and forage production and quality and c) determine the most adaptable WSG species to dryland conditions. A number of dedicated energy crops and their performance across three different moisture regimes in Kansas were studied. Biomass yield, soil physical and hydraulic properties, and soil water and wind erosion parameters were measured between August 2010 and August 2012. Additionally, forage quality under two cutting systems (biofuel and forage) and two harvest heights (0.1 m and 0.2 m) and water infiltration was determined in 2011. Differences in bulk density, water retention, infiltration and SOC were found to be minimal. However, differences in wind and water erosion parameters indicate that WSG can protect soil from erosion. Furthermore, soil water data indicate that WSG are better suited to use early season moisture to accumulate biomass than annual row crops. Yield results indicate that a two cut hay system with a 0.1 m cutting height can produce more biomass compared with a one cut biofuel system. Additionally, the hay system improved forage quality parameters. Data collected from this project provided insights into the viability of growing various dedicated energy crops across the region during the first five years of production.
6

Tar abatement using dolomites during the gasification of pine sawdust

Siemens Gusta, Elizabeth Ursula 18 September 2008
Biofuels like ethanol are gaining serious momentum because of concerns over climate change and the rising cost of fossil fuels. Saskatchewan is the first province in Canada to pass a law requiring ethanol blended into its gasoline. A blend rate of 7.5% is mandated as of January 2007. This legislation is not yet fully enforced as ethanol production cannot currently meet demand, but local production is increasing. The traditional method of production is via grain fermentation; however the food versus fuel debate indicates this is unethical when food shortages and prices are already on the rise. Gasification is a robust technology for processing raw, non-food grade biomass into syngas (H2 and CO) which can then be further converted to ethanol via gas-to-liquid conversion technology. Condensable materials called tars form during gasification and must be further converted to gaseous products to avoid problems downstream. This can be achieved via optimization of process conditions and catalysis. The research for this thesis was carried out in two phases. Phase 1 examined the effects of process conditions on the noncatalytic temperature-programmed gasification of wood (Jack Pine) biomass. Temperature was varied from 700 to 825oC, water flow rate was varied from 2 to 5 cm3/h, and N2 flow rate from 16 to 32 cm3/min. When varying biomass gasification conditions, overall % carbon conversion to gaseous products reached a maximum of 70% at 825oC, 5.0 cm3/h H2O, and 32 cm3/min N2. 670 cm3 product gas per g biomass was produced, with 35.8 mol% H2 and H2:CO of 1.56. In Phase 2, catalytic gasification of wood biomass was carried out using a double bed micro reactor in a two-stage process. Temperature programmed steam gasification of biomass was performed in the first bed at 200-850oC. Following in the second bed was isothermal catalytic decomposition gasification of volatile compounds (including tars). Dolomites from Canada, Australia and Japan were examined for their effects on tar abatement and the overall gaseous product. The gasification of pine sawdust resulted in 74% of carbon emitted as volatile matter during tar gasification (200-500oC biomass bed temperature). High temperature, high H2O flow rate and low carrier gas flow rate are recommended for improving biomass conversion to gaseous products. Dolomites improved tar decomposition by an average 21% at 750oC isothermal catalyst bed temperature. For Canadian dolomites, iron content was found to promote tar conversion and the water-gas shift reaction, but the effectiveness reached a plateau at 1.0 wt% Fe present in dolomite. The best dolomite was Canada # 1, from an area west of Flin Flon, Manitoba. This dolomite yielded 66% tar conversion (25% above noncatalytic results) at 750oC using 1.6 cm3 catalyst/g biomass. Carbon conversion increased to 97% using 3.2 cm3 catalyst/g biomass at the same temperature. The dolomite seemed stable after 15 hours of cyclic use at 800oC.
7

Tar abatement using dolomites during the gasification of pine sawdust

Siemens Gusta, Elizabeth Ursula 18 September 2008 (has links)
Biofuels like ethanol are gaining serious momentum because of concerns over climate change and the rising cost of fossil fuels. Saskatchewan is the first province in Canada to pass a law requiring ethanol blended into its gasoline. A blend rate of 7.5% is mandated as of January 2007. This legislation is not yet fully enforced as ethanol production cannot currently meet demand, but local production is increasing. The traditional method of production is via grain fermentation; however the food versus fuel debate indicates this is unethical when food shortages and prices are already on the rise. Gasification is a robust technology for processing raw, non-food grade biomass into syngas (H2 and CO) which can then be further converted to ethanol via gas-to-liquid conversion technology. Condensable materials called tars form during gasification and must be further converted to gaseous products to avoid problems downstream. This can be achieved via optimization of process conditions and catalysis. The research for this thesis was carried out in two phases. Phase 1 examined the effects of process conditions on the noncatalytic temperature-programmed gasification of wood (Jack Pine) biomass. Temperature was varied from 700 to 825oC, water flow rate was varied from 2 to 5 cm3/h, and N2 flow rate from 16 to 32 cm3/min. When varying biomass gasification conditions, overall % carbon conversion to gaseous products reached a maximum of 70% at 825oC, 5.0 cm3/h H2O, and 32 cm3/min N2. 670 cm3 product gas per g biomass was produced, with 35.8 mol% H2 and H2:CO of 1.56. In Phase 2, catalytic gasification of wood biomass was carried out using a double bed micro reactor in a two-stage process. Temperature programmed steam gasification of biomass was performed in the first bed at 200-850oC. Following in the second bed was isothermal catalytic decomposition gasification of volatile compounds (including tars). Dolomites from Canada, Australia and Japan were examined for their effects on tar abatement and the overall gaseous product. The gasification of pine sawdust resulted in 74% of carbon emitted as volatile matter during tar gasification (200-500oC biomass bed temperature). High temperature, high H2O flow rate and low carrier gas flow rate are recommended for improving biomass conversion to gaseous products. Dolomites improved tar decomposition by an average 21% at 750oC isothermal catalyst bed temperature. For Canadian dolomites, iron content was found to promote tar conversion and the water-gas shift reaction, but the effectiveness reached a plateau at 1.0 wt% Fe present in dolomite. The best dolomite was Canada # 1, from an area west of Flin Flon, Manitoba. This dolomite yielded 66% tar conversion (25% above noncatalytic results) at 750oC using 1.6 cm3 catalyst/g biomass. Carbon conversion increased to 97% using 3.2 cm3 catalyst/g biomass at the same temperature. The dolomite seemed stable after 15 hours of cyclic use at 800oC.
8

Chemical Kinetic Modeling of Biofuel Combustion

Sarathy, Subram Maniam 01 September 2010 (has links)
Bioalcohols, such as bioethanol and biobutanol, are suitable replacements for gasoline, while biodiesel can replace petroleum diesel. Improving biofuel engine performance requires understanding its fundamental combustion properties and the pathways of combustion. This study's contribution is experimentally validated chemical kinetic combustion mechanisms for biobutanol and biodiesel. Fundamental combustion data and chemical kinetic mechanisms are presented and discussed to improve our understanding of biofuel combustion. The net environmental impact of biobutanol (i.e., n-butanol) has not been studied extensively, so this study first assesses the sustainability of n-butanol derived from corn. The results indicate that technical advances in fuel production are required before commercializing biobutanol. The primary contribution of this research is new experimental data and a novel chemical kinetic mechanism for n-butanol combustion. The results indicate that under the given experimental conditions, n-butanol is consumed primarily via abstraction of hydrogen atoms to produce fuel radical molecules, which subsequently decompose to smaller hydrocarbon and oxygenated species. The hydroxyl moiety in n-butanol results in the direct production of the oxygenated species such as butanal, acetaldehyde, and formaldehyde. The formation of these compounds sequesters carbon from forming soot precursors, but they may introduce other adverse environmental and health effects. Biodiesel is a mixture of long chain fatty acid methyl esters derived from fats and oils. This research study presents high quality experimental data for one large fatty acid methyl ester, methyl decanoate, and models its combustion using an improved skeletal mechanism. The results indicate that methyl decanoate is consumed via abstraction of hydrogen atoms to produce fuel radicals, which ultimately lead to the production of alkenes. The ester moiety in methyl decanoate leads to the formation of low molecular weight oxygenated compounds such as carbon monoxide, formaldehyde, and ketene, thereby reducing the production of soot precursors. The study concludes that the oxygenated molecules in biofuels follow similar combustion pathways to the hydrocarbons in petroleum fuels. The oxygenated moiety's ability to sequester carbon from forming soot precursors is highlighted. However, the direct formation of oxygenated hydrocarbons warrants further investigation into the environmental and health impacts of practical biofuel combustion systems.
9

Chemical Kinetic Modeling of Biofuel Combustion

Sarathy, Subram Maniam 01 September 2010 (has links)
Bioalcohols, such as bioethanol and biobutanol, are suitable replacements for gasoline, while biodiesel can replace petroleum diesel. Improving biofuel engine performance requires understanding its fundamental combustion properties and the pathways of combustion. This study's contribution is experimentally validated chemical kinetic combustion mechanisms for biobutanol and biodiesel. Fundamental combustion data and chemical kinetic mechanisms are presented and discussed to improve our understanding of biofuel combustion. The net environmental impact of biobutanol (i.e., n-butanol) has not been studied extensively, so this study first assesses the sustainability of n-butanol derived from corn. The results indicate that technical advances in fuel production are required before commercializing biobutanol. The primary contribution of this research is new experimental data and a novel chemical kinetic mechanism for n-butanol combustion. The results indicate that under the given experimental conditions, n-butanol is consumed primarily via abstraction of hydrogen atoms to produce fuel radical molecules, which subsequently decompose to smaller hydrocarbon and oxygenated species. The hydroxyl moiety in n-butanol results in the direct production of the oxygenated species such as butanal, acetaldehyde, and formaldehyde. The formation of these compounds sequesters carbon from forming soot precursors, but they may introduce other adverse environmental and health effects. Biodiesel is a mixture of long chain fatty acid methyl esters derived from fats and oils. This research study presents high quality experimental data for one large fatty acid methyl ester, methyl decanoate, and models its combustion using an improved skeletal mechanism. The results indicate that methyl decanoate is consumed via abstraction of hydrogen atoms to produce fuel radicals, which ultimately lead to the production of alkenes. The ester moiety in methyl decanoate leads to the formation of low molecular weight oxygenated compounds such as carbon monoxide, formaldehyde, and ketene, thereby reducing the production of soot precursors. The study concludes that the oxygenated molecules in biofuels follow similar combustion pathways to the hydrocarbons in petroleum fuels. The oxygenated moiety's ability to sequester carbon from forming soot precursors is highlighted. However, the direct formation of oxygenated hydrocarbons warrants further investigation into the environmental and health impacts of practical biofuel combustion systems.
10

Cellulosic ethanol feasibility framework

Sawatzky, Curtis 08 January 2013 (has links)
The objective was to create a feasibility framework for assessing the feasibility of a cellulosic ethanol refinery. In addition, the research aimed to create a base case scenario based on data from literature and conduct sensitivity analysis to determine significant parameters of a cellulosic ethanol refinery. The base case was found to be not feasible in the financial and economic analysis given the assumptions used.

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