Depletion of fossil fuel reserves along with growing environmental concerns has shifted focus towards renewable energy sources for liquid fuels production, such as biofuels. Most biofuels, like ethanol, are single-component fuels that cannot meet today's engine specifications unless they are blended with petroleum feedstocks. Current transportation infrastructure uses petroleum fuels that are mixtures of compounds. Therefore, it is important to be able to produce multi-component fuels in a cost effective way, from renewable resources. Aqueous-phase hydrogenation reactions are crucial in converting biomass-derived molecules into liquid fuels and chemicals. It is possible to produce multi-component fuels through the hydrogenation of bio-oils in the aqueous phase. One of the hardest functionalities to be hydrogenated in bio-oils is the carboxylic acids. Our findings on acetic acid hydrogenation studies over monometallic catalysts will be discussed combined with insight learned from DFT calculations. Ruthenium has been shown to be the most active and selective catalyst towards ethanol formation. Acetyl species appears to be a key component as its formation is the rate-determining step for almost all catalysts. Another way of making multi-component fuels is by the liquid-phase processing of the hemicellulose portion of biomass. It will be shown that hemicellulose-derived aqueous feedstocks can be converted into a petroleum feedstock that can readily be processed in existing petroleum refineries to make a variety of fuels. Furfural is produced in high yields from the dehydration of hemicellulose-derived sugar streams. The aldol condensation of furfural with acetone gives highly conjugated C13 compounds along with some polymeric adducts. In the presence of supported metal catalyst these compounds undergo hydrogenation, and at the same time, form heavy cyclic molecules via Diels-Alder reactions. Through hydrodeoxygenation and isomerization over bifunctional catalysts these molecules produce refinery feedstocks, or more specifically, fluid catalytic cracker cycle oil substitutes, having carbon numbers up to C31. This integrated catalytic process can be tuned to adjust the yield of the hydrocarbon products thereby selectively producing jet and diesel fuel range compounds or a heavier petroleum refinery feedstock. This study demonstrates that biomass can produce mixtures of components that can fit seamlessly into petroleum refinery infrastructure.

Due to its low cost and large availability lignocellulosic biomass is being studied worldwide as a feedstock for renewable liquid biofuels. Currently there are several routes being studied to convert solid biomass to a liquid fuel, which involve multiple steps at long residence times thus greatly increasing the cost of biomass processing. Catalytic fast pyrolysis (CFP) is a new promising technology to convert directly solid biomass to gasoline-range aromatics that fit into the current infrastructure. CFP involves the rapid heating of biomass (~500˚C sec-1) in an inert atmosphere to intermediate temperatures (400 to 600 ˚C) in the presence of zeolite catalysts. During CFP, biomass is converted in a single step to produce gasoline-range aromatics which are compatible with the gasoline of the current market. CFP has many advantages over other conversion processes including short residence times (2-10 s) and inexpensive catalysts. The major impediment to the further development of CFP is the lack of fundamental understanding of the underlying chemistry of the process. The first goal of this thesis is to study the underlying chemistry of the CFP process using model compounds in a small pyroprobe micro reactor. For this part of the study the homogeneous thermal decomposition routes of glucose were identified along with the key intermediates. Through isotopic labeling studies the heterogeneous C-C bond forming reactions were determined. Lastly, the relative rates of the homogeneous and heterogeneous reactions were estimated. Since CFP in the small pyroprobe reactor is not scalable the second part of the study focused on designing and building a bench scale fluidized bed reactor to demonstrate CFP on a larger scale. This fluidized bed reactor was used to optimize the CFP of pine wood with ZSM-5 catalyst. The effect of reaction conditions such as temperature and biomass space velocity on the aromatic yield and selectivity was determined. The long term stability of the catalyst was also studied.

No description available.

<p> People in developing countries have limited access to electricity, especially in rural and remote areas. As electricity consumption is correlated with economic development, the lack of access to electricity is a key obstacle to achieving economic growth. Techniques for improving access to electricity include grid extension and distributed energy resources (DER), but analyzing the tradeoff between grid extension and distributed generation requires a better understanding of the impacts of grid unreliability. In this dissertation, a new method for simulating unreliable electric grids is presented. The method is then used to determine the cost of reliable electricity in areas where the grid is unreliable. The method is extended in order to calculate the distance at which grid extension of an unreliable grid and DER have the same cost, a point known as the economic distance limit (EDL). Finally, the method is applied to analyze the impact of grid sell-back prices on electricity cost and EDL. The methods are demonstrated for a village in Uganda, but hold universally. Results indicate that demand for increased availability increases cost, but now the cost per unit of availability can be calculated and used in decision making. Similarly, with fixed demand availability, we see increasing costs as grid availability decreases. This also results in EDL decreasing as grid availability decreases, as there is little value in extending a grid that functions poorly. From the simulation results, linear approximations of some of the key outputs are developed and are demonstrated to be consistent with results. These provide a method for rapidly calculating electricity costs and EDL without the need to perform numerous simulations. Simple calculations for cost of highly available electricity will enable more informed choices for grid-tied and stand-alone electricity generation for system operators and for policy makers.</p>

<p> The primary aim of this study was to develop mesoporous nanocatalysts for (i) hydrogen production via steam reforming of methanol (SRM) in a tubular reactor, and (ii) syngas conversion to hydrocarbons via Fisher-Tropsch synthesis using silicon microchannel microreactors. The mesoporous catalysts for SRM were prepared by an optimized one-pot hydrothermal synthesis procedure. The catalysts were investigated for SRM activity in a packed bed tubular reactor using metals, namely, Cu, Co, Ni, Pd, Zn, and Sn. The metals were incorporated in different supports -MCM-41, SBA-15, CeO₂, TiO₂, and ZrO₂ to investigate the influence of support on catalyst properties. A sharp contrast in catalyst performance was noticed depending on the type of support employed. For example, in SRM at 250 &deg;C, Cu supported on amorphous silica SBA-15 and MCM-41 produced significantly less CO (&lt; 7%) compared to other crystalline supports Cu-TiO₂ and Cu/ZrO₂ that showed high CO selectivity of &sim;56% and &sim;37%, respectively. Amongst all the metals studied for SRM activity using 1:3 methanol:water mole ratio at 250 &deg;C, 10%Cu-MCM-41 showed the best performance with 68% methanol conversion, 100% H₂ , &sim;6 % CO, 94% CO₂ selectivities, and no methane formation. Furthermore, 10%Cu-CeO₂ yielded the lowest CO selectivity of 1.84% and the highest CO2 selectivity of &sim;98% at 250 &deg;C. Stability studies of the catalysts conducted for time-on-stream of 40 h at 300 &deg;C revealed that Cu-MCM41 was the most stable and displayed consistent steady state conversion of &sim;74%. Our results indicate that, although coking played an influential role in deactivation of most catalysts, thermal sintering and changes in MCM-41 structure can be responsible for the catalyst deactivation. For monomtetallic systems, the MCM-41 supported catalysts especially Pd and Sn showed appreciable hydrothermal stability under the synthesis and reaction conditions. While bimetallic Pd-Co-MCM-41 and Cu-Ni-MCM-41 catalysts produced more CO, Cu-Zn-MCM-41 and Cu-Sn-MCM-41exhibited better SRM activity, and produced much less CO and CH4. In spite of the improved the stability and dispersion of the monometallic active sites in the support, no noticeable synergistic activity was observed in terms of H₂ and CO selectivities in the multimetallic catalysts. For the Fisher-Tropsch (F-T) studies, Co-TiO₂, Fe-TiO₂ and Ru-TiO₂ catalysts were prepared by the sol-gel method and coated on 116 microchannels (50&mu;m wide x 100&mu;m deep) of a Si-microreactor. The F-T process parameters such as temperature, pressure and flow rates were controlled by an in-house setup programmed by LabVIEW^&reg;. The effect of temperature on F-T activity in the range of 150 to 300&deg;C was investigated at 1 atm, a flow rate of 6 ml/min and a constant H₂:CO molar ratio of 2:1. In our initial studies at 220 &deg;C, 12%Ru-TiO₂ showed higher CO conversion of 74% and produced the highest C₂-C₄ hydrocarbon selectivity-of &sim;11% ethane, 22% propane and &sim;17% butane. The overall catalyst stability and performance was in the order of 12%Ru-TiO₂>> 12%Fe-TiO₂ > 12%Co-TiO₂.</p>

<p> At the rate the population is growing it is important to find ways to be more efficient with the energy and water we use. The increase in population increases the need for electricity and water, but the way we are using our sources will not leave us with enough for future generations. The constant use of &ldquo;dirty energy&rdquo;, energy that emits CO2 and other chemicals into the atmosphere, will continue to harm our environment. A new system is needed to help preserve water and produce green energy that will not harm the only earth we have.</p>

<p> Bangladesh has experienced significant energy shortfalls in the electrical grid since at least 2005 and the majority of people living outside urban areas do not have access to electricity. Solar energy is an attractive form of supplemental electrical energy. One approach to implementing solar electric energy systems in Bangladesh is the Solar Home System (SHS), an off grid Photovoltaic (PV) solar energy system. With over 3 million solar home systems already installed, it is an increasingly important component of rural energy. The SHS as it currently exists only enables limited loads, such as lights and televisions, is relatively expensive and has some significant technical issues. </p><p> This research study attempts to explore how distributed PV can be improved, using Bangladesh as a case study. Literature is reviewed to determine interactions and elements of distributed PV systems. A quantitative Social, Technological, Economic, Environmental and Political (STEEP) index is developed. A software program called <i>poplar</i> is developed to evaluate the existing Solar Home System using the proposed STEEP index. This is compared to an alternative topology incorporating distributed energy storage elements into loads to provide flexibility and scalability in system usage and reliability. The developed model simulation indicates that implementing distributed energy storage elements allows reduction of PV module and storage size. While there is significant uncertainty in the cost and environmental impact of the power electronics, this smaller sizing is correlated with total reduction in system price and environmental impact. The conclusion to this study is that the current SHS configuration may be better optimized by incorporating distributed energy storage into the loads.</p>

abstract: In the past, the photovoltaic (PV) modules were typically constructed with glass superstrate containing cerium oxide and EVA (ethylene vinyl acetate) encapsulant containing UV absorbing additives. However, in the current industry, the PV modules are generally constructed without cerium oxide in the glass and UV absorbing additives in EVA to increase quantum efficiency of crystalline silicon solar cells in the UV regions. This new approach is expected to boost the initial power output of the modules and reduce the long-term encapsulant browning issues. However, this new approach could lead to other durability and reliability issues such as delamination of encapsulant by damaging interfacial bonds, destruction of antireflection coating on solar cells and even breakage of polymeric backbone of EVA. This work compares the durability and reliability issues of PV modules having glass without cerium oxide and EVA with (aka, UVcut or UVC) and without (aka, UVpass or UVP) UV absorbing additives. In addition, modules with UVP front and UVC back EVA have also been investigated (aka, UVhybrid or UVH). The mini-modules with nine split cells used in this work were fabricated at ASU’s Photovoltaic Reliability Laboratory. The durability and reliability caused by three stress variables have been investigated and the three variables are temperature, humidity/oxygen and UV dosage. The influence of up to 800 kWh/m2 UV dosage has been investigated at various dosage levels. Many material and device characterizations have been performed to ascertain the degradation modes and effects. The UVC modules showed encapsulant discoloration at the cell centers as expected but the UVH modules showed a ring-shaped encapsulant discoloration close to the cell edges as evidenced in the UV fluorescence (UVF) imaging study. The PV modules containing UVP on both sides of cells with limited access to humidity or oxygen through backsheet (covered backsheet with adhesive aluminum tape) seem to experience encapsulant delamination as evidenced in the UVF images. Plausible explanations for these observations have been presented. / Dissertation/Thesis / Masters Thesis Chemical Engineering 2019

This dissertation examines the influence that economic and technological factors have on the penetration of biodiesel and ethanol into the transportation fuels market. This dissertation focuses on four aspects. The first involves the influence of fossil fuel prices, because biofuels are substitutes and have to compete in price. The second involves biofuel manufacturing technology, principally the feedstock-to-biofuel conversion rates, and the biofuel manufacturing costs. The third involves prices for greenhouse gas offsets. The fourth involves the agricultural commodity markets for feedstocks, and biofuel byproducts. This dissertation uses the Forest and Agricultural Sector Optimization Model-Greenhouse Gas (FASOM-GHG) to quantitatively examine these issues and calculates equilibrium prices and quantities, given market interactions, fossil fuel prices, carbon dioxide equivalent prices, government biofuel subsidies, technological improvement, and crop yield gains. The results indicate that for the ranges studied, gasoline prices have a major impact on aggregate ethanol production but only at low prices. At higher prices, one runs into a capacity constraint that limits expansion on the capacity of ethanol production. Aggregate biodiesel production is highly responsive to gasoline prices and increases over time. (Diesel fuel price is proportional to the gasoline price). Carbon dioxide equivalent prices expand the biodiesel industry, but have no impact on ethanol aggregate production when gasoline prices are high again because of refinery capacity expansion. Improvement of crop yields shows a similar pattern, expanding ethanol production when the gasoline price is low and expanding biodiesel. Technological improvement, where biorefinery production costs decrease over time, had minimal impact on aggregate ethanol and biodiesel production. Finally, U.S. government subsidies have a large expansionary impact on aggregate biodiesel production, but only expand the ethanol industry at low gasoline prices. All of these factors increase agricultural welfare with most expanding producer surplus and mixed effects on consumers.

ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / A monitoring system has been developed to detect when a large vehicle is gaining access to an area such as an agricultural field or facility through a control gate. The system uses multiple sensors, including Hall-effect, anisotropic magnetoresistor, ultrasonic ranging, and vision. A user is alerted using a conventional cell phone network of the presence of the vehicle. The system is microcontroller based, uses photovoltaic power supply, and leverages commercial off the shelf components wherever feasible. The system detection algorithm was made adaptable, to minimize false alarms and missed detections.