Lithium orthosilicate (Li4SiO4) is known to be a high temperature CO2 capture material. This work was focused on comparing Li4SiO4 to the extensively studied CaO as an adsorbent in sorption enhanced catalysis. Thermogravimetric analysis was used to study the effects of sorption temperature and compaction on Li4SiO4 using 15vol% CO2 in N2. After 2 hours of CO2 adsorption at 550°C the powder reached 35wt% uptake of CO2, corresponding to 93.6% of maximum efficiency and complete regeneration was possible at 700°C. Pressing Li4SiO4 to granular forms greatly decreased CO2 adsorption rates. Efforts to impregnate -Al2O3 with the suspended SiO2 solution from aqueous based sol-gel synthesis to produce nanodispersed Li4SiO4 failed due to the inability to form the targeted Li4SiO4 complex. X-ray diffraction analysis indicated the formation of the gel is crucial for the formation of the crystalline Li4SiO4 phase. A microreactor was used to study the steam reforming of ethanol over a series of 1% Pt on -Al2O3 catalyst composite impregnated over a range of nanodispersed CaO loading at S/C=1.5 in dilution. At 400°C enhancement could be observed with the presence of CaO sorbent compared to only 1% Pt/Al2O3. However, production quickly diminished due to high carbon deposition. For 1% Pt/Al2O3 tested at 400°C, ethylene production was 5 times higher than for hydrogen. Above 550°C the ethylene production was reduced to 0.18vol% and gas production stability was greatly improved for 1% Pt/Al2O3 and even more so with the addition of impregnated CaO sorbent. Hydrogen yields from homogeneous mixtures of 1%Pt/Al2O3 with Li4SiO4 powder in a microreactor were about 20% higher than those achievable of the same mixture with CaO powder. However, the composite 1%Pt/Al2O3 with 7.02wt% dispersed CaO gave 100% higher hydrogen production under similar conditions despite Li4SiO4 being a superior carbon capture material. / Litiumortosilikat (Li4SiO4) är ett känt CO2 adsorptionsmaterial vid höga temperaturer. Fokuset i detta arbete var att jämföra Li4SiO4 med det välstuderade CaO som adsorbent i adsorptionsförbättrad katalys. Termogravimetrisk analys användes för att studera effekten av temperatur och kompaktering på Li4SiO4 med 15vol% CO2 i balanserad N2. Efter 2 timmars CO2 adsorption vid 550°C hade pulvret nått 35vikt% ökning av CO2, vilket korresponderar till 93.6% av den maximala verkningsgraden. Dessutom var fullständig regenerering möjlig vid 700°C. Pressad Li4SiO4 i grynig form sänkte CO2 adsorptionshastigheten signifikant. Försök att impregnera -Al2O3 med suspenderad SiO2 från en vattenbaserad sol-gel metod för att bilda nanodispergerad Li4SiO4 misslyckades på grund av oförmågan att bilda önskade Li4SiO4 komplex. Röntgendiffraktions analys tydde på att bildningen av gelen var avgörande för bildningen av en kristallin Li4SiO4 fas. En mikroreaktor användes för att studera ångreformeringen av etanol hos 1% Pt på - Al2O3 katalysator komposit impregnerad med ett varierande tillskott av nanodispergerad CaO i utspädd S/C=1.5. Vid 400°C kunde en förbättring observeras då CaO var närvarande jämfört med endast 1% Pt/Al2O3. Dock minskade gasproduktionen kraftigt på grund av hög koksning. Tester på 1% Pt/Al2O3 vid 400°C visade att eten produktionen var 5 gånger högre än för vätgasproduktionen. Över 550°C sjunkte eten produktionen till 0.18vol% och gas produktionsstabiliteten förbättrades signifikant för 1% Pt/Al2O3 och även bättre i närvaro av nanodispergerad CaO. Vätgasutbytet från en homogen blandning av 1% Pt/Al2O3 med Li4SiO4 pulver i en mikroreaktor var 20% högre än det som åstadkoms för samma blandning med med CaO pulver. Dock visade 1%Pt/Al2O3 med 7.02vikt% dispergerad CaO 100% högre vätgasproduktion under liknande förhållanden trots att Li4SiO4 är en överlägsen koluppfångar material.

El Capítulo I trata la actual crisis energética y hace una breve introducción sobre el uso del hidrógeno como vector energético, mencionando los diferentes métodos que pueden utilizarse para la producción/purificación de hidrógeno a partir de recursos renovables. También incluye una breve descripción del papel que puede jugar la biomasa como alternativa a los combustibles fósiles, y su conversión a biocombustibles y productos químicos de valor añadido. El reformado catalítico de glicerol para la producción de gas de síntesis o corrientes ricas en hidrógeno se presenta como una ruta potencial, alternativa y prometedora que ha llamado la atención en los últimos años. Esta reacción se suele llevar a cabo sobre catalizadores basados en metales soportados en materiales estables. En el Capítulo II se estudia el efecto de la adición de Sn sobre las propiedades y la estabilidad de catalizadores de Pt soportado en carbón en la reacción de reformado glicerol en fase gas. Para ello, se preparó y caracterizó una serie de catalizadores con diferentes relaciones atómicas Pt/Sn. El alto precio de los metales nobles motiva la búsqueda y empleo de metales más baratos y abundantes que también tengan un buen comportamiento catalítico en esta reacción. Por ello, en el Capítulo III se emplearon catalizadores basados en Ni promovidos por óxido de cerio para el reformado de glicerol. Por otro lado, se hace necesario optimizar el uso del CeO2 debido a su limitada disponibilidad y sus extensas aplicaciones. Así, en este trabajo se dispersó CeO2 sobre carbón activado de alta área superficial, obteniendo gran superficie de óxido de cerio expuesta al mismo tiempo que se redujo su consumo. También se estudió el efecto de la presencia de estaño en estos catalizadores. Se obtienen diversas ventajas al realizar el reformado de glicerol en fase líquida. Así, se obtienen corrientes más ricas en H2 con menor cantidad de CO. Esto se debe a las moderadas temperaturas y altas presiones empleadas, que favorecen la reacción de desplazamiento del gas de agua. También se suprime la necesidad de evaporar la disolución acuosa de glicerol, por lo que el requerimiento energético es menor y se evitan reacciones indeseadas de descomposición térmica. De este modo, en el Capítulo IV se hace un estudio comparativo sobre las propiedades catalíticas de tres muestras, Pt/CeO2, Ni/CeO2 y Pt-Ni/CeO2, en la reacción de reformado de glicerol en fase líquida. Además, se empleó espectroscopía de reflectancia total atenuada in situ para obtener información relevante sobre los intermedios de reacción y la evolución de los catalizadores durante la reacción, permitiendo así proponer los caminos de reacción más probables. Para obtener corrientes de hidrógeno suficientemente puro para su uso es las pilas de combustible, la corriente obtenida después del reformado debe ser procesada en varias etapas, entre las que se incluyen la eliminación del CO por medio de la reacción de desplazamiento del gas de agua (water-gas shift, WGS). En el Capítulo V se estudia la serie de catalizadores de Ni promovidos por CeO2 soportados en carbón en la reacción de desplazamiento del gas de agua a bajas temperaturas. Para este estudio se emplearon diferentes corrientes de entrada, tanto ideales (sólo CO y H2O) como reales (CO, CO2, H2 y H2O). Por último, en el Capítulo VI, el catalizador que presentó mejor comportamiento catalítico en el apartado anterior fue estudiado en mayor profundidad, relacionando sus propiedades con la actividad catalítica, sometiéndolo finalmente a ensayos de estabilidad en condiciones más demandantes.

Many countries around the world have decided to play a positive role in combating climate change and reduce carbon dioxide in the atmosphere. In addition to reducing emissions, initiatives include the capture, storage and utilization of CO2. Converting it to valuable products through reforming of methane not only utilizes major greenhouse gasses, but can also be a means for energy from biogas. The main challenge hindering this process is developing a scalable active catalyst that can resist deactivation. To address this challenge, focus has shifted from simple metal oxides towards metal nanoparticles dispersed and organized in complex well defined structures. Oxide perovskites have the potential to contain metal and support in a single structure as the case of LaNiO3. Metal-organic frameworks are another type of materials that can be used as sacrificial agents to produce the type of complex metal oxides required. Three synthesis approaches were studied for the synthesis of La-Ni materials. Combustion synthesis is a cost and time efficient method. However, it becomes challenging to accurately predict the outcomes. Hydrothermally synthesized perovskites give pure phase materials but are sensitive to synthesis variables. MOF based materials showed conversions of 94% and 83% for CO2 and CH4, respectively, with stable performance for +100 hours and can be a promising future route in heterogeneous catalysis.

In light of global warming’s environmental implications, research is shifted towards potential processes that can utilize CO2 and reduce its emissions in the industrial sector. One of the promising processes is dry reforming of methane (DRM), which is capable of utilizing CO2 and producing valuable syngas (H2 and CO). The main challenge of DRM is the deactivation of catalysts under the reaction temperatures (above 700 °C) due to sintering of the active metal and coke formation. Ni-based catalysts are the most widely investigated catalysts in literature for DRM due to their cost efficiency and availability. This study is an extension of the work done by Saudi Basic Industries Corporation (SABIC) devoted to investigating Ni-Ce-In system for DRM reaction. Five catalysts were synthesized by dry impregnation method according to SABIC synthesis procedure (Ni/Al2O3, Ni-In/Al2O3, Ni/CeO2/Al2O3, Ni/In-CeO2/Al2O3, and Ni-In/CeO2/Al2O3). The metallic loading targets were 7.5 wt.%, 10 wt.%, and 0.8 wt.% for nickel, cerium, and indium, respectively. The addition of indium in combination with cerium resulted in the highest catalytic activity. Additionally, the co-impregnation of indium and cerium resulted in enhancing the catalytic activity more than subsequential impregnation (Ni/In-CeO2/Al2O3 compared to Ni-In/CeO2/Al2O3). The addition of cerium or indium separately with nickel did not seem to affect activity since Ni/Al2O3, Ni-In/Al2O3, and Ni/CeO2/Al2O3 exhibited similar conversion values. All catalysts were stable for more than two days under DRM conditions without deactivating. Therefore, deactivation behaviors of the catalysts were not covered in this study.

Master Thesis, Department of Mechanical Engineering / A comprehensive analytical model of an indirect internal reforming type tubular Solid Oxide Fuel Cell (IIR-T-SOFC) has been developed. Two-dimensional axisymmetric multicomponent gas flow fields and quasi-three-dimensional electric potential/current fields in the tubular cell are simultaneously treated in the model with consideration of the involved phenomena such as internal reforming, electrochemical reactions and radiative heat transfer. By using this model, the characteristics of the operating state of an IIR-T-SOFC were numerically examined. As a result, it was shown how the thermal field and power generation characteristics of the cell were affected by the gas inlet temperature, air flow rate, steam-methane ratio, reforming catalyst distribution and thickness of the electrodes. In particular, the optimized catalyst distribution greatly reduced both the maximum temperature and temperature gradients of the cell with little negative impact on the power generation performance of the cell. / 京都大学 / 0048 / 修士 / 修士(工学) / Kyoto University / TFtmp

While the quest of the human civilization continues towards a more sustainable energy resource, current energy conversion technologies need to be improved such that the rate of environmental impact that has occurred due to the rapid industrialization since the 20th century is mitigated. This search has motivated research into new energy conversion technologies that aim to reduce the environmental impact by either improving the efficiencies of existing technologies, developing new technologies with zero emissions or by improving reliability and reducing the cost of renewable energy. Process intensification through process integration is one of the areas of active research that improves the system efficiency by exploiting the synergies that exist between different processes. This thesis considers the design and operational feasibility of heat integrating two conventional industrial processes – gasification and steam reforming of methane for application in polygeneration. To this end, complex mathematical models that describe the integrated system are developed to study different design prospects and to determine if the device can be safely operated in a plant producing electricity, liquid fuels and hydrogen. The designs proposed in this thesis show that significant methane conversion comparable to industrial reformers can be achieved while providing the required cooling duty to the gasifier. The proposed integrated system produces hydrogen rich reformer synthesis gas (hydrogen and carbon monoxide) that can be blended with the hydrogen lean coal synthesis gas providing flexibility to change the molar H2/CO ratio necessary for different downstream processes in a polygeneration plant. Moreover, the results show that the integration helps improve plant carbon efficiency and reduce CO2 emissions. The major contribution of this thesis is the development of designs based on representative mathematical models that are safe to operate for producing several chemicals in polygeneration plants. / Dissertation / Doctor of Philosophy (PhD)

Due to the advancement of global warming internationally, increasing emphasis is being placed on the environmental accountability of everyone from countries to processes. This study presents novel research on the environmental impacts and economic trade-offs for a processes co-producing electricity, methanol, dimethyl ether (DME) and Fischer Tropsch (FT) fuels from different feedstock ratios of biomass, natural gas, and nuclear hydrogen generated through a CuCl cycle are analyzed for operation in Canada to produce transportation fuels. This study also considers the use of carbon capture and sequestration (CCS), the location of the plant in either Ontario and Alberta, and the input ratio of the feedstocks. This combination of carbonless heat and a “carbon neutral” biomass feedstock would contribute to the net reduction of greenhouse gas (GHG) emissions. In Part I of this work, the model for this BGNTL process was developed. This work expands on the model and evaluates the economics and environmental impacts this plant would have in both Ontario and Alberta based on their local costs, resource availability, and current electricity grid contributions. The analysis investigates the effectiveness of the emission reduction of the products and processes when compared to their cost. It is shown that an increase in the ratio of biomass to natural gas in feedstock, the use of a solid oxide fuel cell (SOFC), and the production of additional electricity while reducing the emissions of the process, increases the cost of CO2e avoided. The results show that the BGNTL concept can be an economically attractive way of reducing net transportation sector GHG emissions in both Ontario and Alberta in meaningful quantities. Optimal cases for both biofuel and FT fuel production contain a single output fuel production process, produce fuels over electricity where possible, and use a gas turbine (GT) for the electricity production that occurs. / Thesis / Master of Engineering (MEngr) / This paper examines a system producing a combination of transportation fuels including diesel, gasoline, methanol (MeOH), dimethyl ether (DME) and electricity from biomass, natural gas and hydrogen. The design of the system units used in the process was done in a previous study, this work expands on the design looking specifically at locating the plant in Ontario and Alberta for their raw resources, electricity grids, and current production methods of fuel. Variations of the plant are compared to each other and current fuel and electricity production with an aim of reducing the cost and emissions created while producing and using the fuels. It is found that increasing the amount of biomass used significantly reduces the emissions but does not create a competitive process due to how expensive it is. Results show that this type of system can decrease transportation sector emissions with a similar additional cost as other current alternatives.

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