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LTA-type zeolites with narrow window apertures coinciding with the approximate size of small gaseous molecules such as CO2 and N2 are interesting candidates for adsorbents with swing adsorption technologies due to their molecular sieving capabilities and otherwise attractive properties. These sieving capabilities are dependent on the energy barriers of diffusion between the zeolite pores, which can be fine-tuned by altering the framework composition. An ab initio level of theory is necessary to accurately describe specific gas-zeolite interaction and diffusion properties, while it is desirable to predict the macroscopic scale diffusion for industrial applications. Hence, a multiscale modeling approach is necessary to describe the molecular sieving phenomena exhaustively. In this thesis, we use several different modeling methods on different length and time scales to describe the diffusion driven uptake and separation of CO2 and N2 in Zeolite NaKA. A combination of classical force field based modeling methods are used to show the importance of taking into account both thermodynamic, as well as, kinetic effects when modeling gas uptake in narrow pore zeolites where the gas diffusion is to some extent hindered. For a more detailed investigation of the gas molecules’ pore-to-pore dynamics in the material, we present a procedure to compute the free energy barriers of diffusion using spatially constrained ab initio Molecular Dynamics. With this procedure, we seek to identify diffusion rate determining local properties of the Zeolite NaKA pores, including the Na+-to-K+ exchange at different ion sites and the presence of additional CO2 molecules in the pores. This energy barrier information is then used as input for the Kinetic Monte Carlo method, allowing us to simulate and compare these and other effects on the diffusion driven uptake using a realistic powder particle model on macroscopic timescales. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>

Abstract Energy production in combustion power plants is a significant source of anthropogenic carbon dioxide emissions. The targets of international climate agreements call for utilizing all available technologies to achieve rapid and cost-effective emission reductions. Carbon capture and storage is one of the possible technical solutions applied in combustion power plants. Circulating fluidized bed boilers have gained increasing popularity due to advantages in availability, emission control, fuel flexibility and option for using challenging fuels, and the possibility of using high-efficiency steam cycles. In the novel process of oxy-combustion, combustion air is replaced by a mixture of oxygen and recycled flue gas to facilitate the capture of carbon dioxide from the flue gas flow. Additional degrees of freedom become available for combustion control as the gas flow and composition can be controlled separately for fluidization and combustion purposes. In the research for this thesis, self-optimizing control was applied for the control structure design of a circulating fluidized bed boiler. Self-optimizing control offers a systematic tool for the early phases of control design, in which decisions have traditionally been made based on intuition, heuristics and previous experience. The self-optimizing control approach searches for controlled variables without a need for constant setpoint optimization when the process is affected by disturbances and implementation errors. Results presented in the thesis show that self-optimizing control can be applied in the control structure design of circulating fluidized bed combustion. A range of control structure alternatives were evaluated using steady-state approximations of a validated process model. For the novel oxy-combustion process, promising control structures were identified and could be dynamically demonstrated. / Tiivistelmä Energiantuotanto polttovoimalaitoksissa on merkittävä hiilidioksidipäästöjen lähde. Kansainväliset ilmastotavoitteet edellyttävät kaikkien käytettävissä olevien teknologioiden hyödyntämistä päästövähennysten aikaansaamiseksi nopeasti ja kustannustehokkaasti. Hiilidioksidin talteenotto on yksi mahdollisista teknisistä ratkaisuista polttovoimalaitoksissa. Kiertoleijukattilat ovat saavuttaneet kasvavaa suosiota etuinaan hyvä käytettävyys, tehokas päästöjen hallinta, soveltuvuus erilaisten haastavienkin polttoaineiden hyödyntämiseen ja mahdollisuus tehokkaiden höyrykiertojen käyttöön. Uudessa happipolttoprosessissa palamisilma korvataan hapen ja kierrätetyn savukaasun seoksella, mikä mahdollistaa hiilidioksidin talteenoton savukaasuista. Kiertoleijupolton säädön kannalta vapausasteet lisääntyvät, sillä leijutukseen ja polttamiseen käytettävän kaasun määrää ja koostumusta voidaan säätää erikseen. Väitöstutkimuksessa käytettiin itseoptimoivaa säätöä kiertoleijukattilan säätörakenteiden suunnitteluun. Itseoptimoiva säätö tarjoaa systemaattisen menetelmän säätösuunnittelun alkuvaiheeseen, jossa päätöksenteko on perinteisesti tehty esimerkiksi intuition, heuristiikan ja aiempien ratkaisujen perusteella. Menetelmän tavoitteena on löytää säädettävät muuttujat, joiden asetusarvot eivät vaadi jatkuvaa optimointia, vaikka prosessiin vaikuttavat erilaiset häiriöt ja mittausvirheet. Väitöstutkimuksen tulokset osoittavat, että itseoptimoiva säätö soveltuu kiertoleijupolton säätörakenteiden suunnitteluun. Erilaisten säätörakenteiden toimivuutta arvioitiin käyttäen validoidun prosessimallin tasapainotilan approksimaatioita. Uudelle happipolttoprosessille löydettiin lupaavia säätörakenteita, joiden toimintaa voitiin demonstroida myös dynaamisesti.

Submitted by Morgana Andrade (morgana.andrade@ufes.br) on 2016-04-08T19:15:45Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) tese_9214_Pedro Junior Zucatelli - verso final.pdf: 4865384 bytes, checksum: 570b50189e5399bc757b7e56ec6fff81 (MD5) / Approved for entry into archive by Patricia Barros (patricia.barros@ufes.br) on 2016-05-13T13:42:31Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) tese_9214_Pedro Junior Zucatelli - verso final.pdf: 4865384 bytes, checksum: 570b50189e5399bc757b7e56ec6fff81 (MD5) / Made available in DSpace on 2016-05-13T13:42:31Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) tese_9214_Pedro Junior Zucatelli - verso final.pdf: 4865384 bytes, checksum: 570b50189e5399bc757b7e56ec6fff81 (MD5) / Conforme reconhecido pelo Protocolo de Kyoto, planejar um futuro energético ecologicamente correto é o grande desafio do Século XXI. Os padrões atuais de recursos energéticos e de uso de energia se mostram prejudiciais para o bem-estar da humanidade ao longo prazo. A integridade dos sistemas naturais essenciais já está em risco devido às mudanças climáticas causadas pelas intensas emissões dos Gases de Efeito Estufa na atmosfera. Neste contexto, o Sequestro Geológico de Carbono (ou Carbon Capture and Storage – CCS) é uma atividade promissora que visa contribuir para a redução da emissão dos gases causadores do efeito estufa e a mitigação das alterações climáticas, por meio da captura, transporte e armazenamento de CO2 em formações geológicas adequadas (aquíferos salinos, reservatórios de hidrocarbonetos e reservatórios de carvão). Portanto, inserida neste cenário, esta Dissertação teve como objetivo analisar o potencial técnico do sequestro geológico de CO2 na Bacia do Espírito Santo onshore e offshore abordando os ambientes geológicos propícios para a aplicação de projetos de CCS, as fases que compõem estes projetos, seus investimentos e custos operacionais. Além disso, foi realizada a modelagem matemática da potencialidade de armazenamento assim como a estimativa de rentabilidade financeira com a execução do projeto de armazenamento por meio da venda do óleo extra produzido pela técnica de recuperação avançada de petróleo e pela comercialização dos Créditos de Carbono. Para isso, este projeto teve como estratégia metodológica: a xviii pesquisa exploratória e a revisão da literatura relacionada com o tema, a coleta de dados secundários, via análise de documentos, e a coleta de dados primários, via entrevistas com experts e participações em congressos nacionais e internacionais voltados para o tema. Sendo assim, conclui-se que os projetos de CCS são possíveis de implantação no estado do Espírito Santo, isto porque além da estrutura geológica dos reservatórios de petróleo e gás da bacia capixaba contribuir para bons resultados (pois, na maioria dos casos, são reservatórios areníticos com presença de rocha selante), o potencial dos aquíferos salinos capixabas e o potencial dos campos de hidrocarbonetos estudados nesta dissertação (Campo de Golfinho, Inhambú, Fazenda Alegre, Cação, Canapu, Cangoá, Peroá e Camarupim) merecem destaque nacional; entretanto, a falta de maturidade dos setores privado e público, com relação ao gerenciamento dos projetos desta natureza e ao seu uso em larga escala, impede o avanço de tais tecnologias no estado do Espírito Santo e, por consequência, no Brasil. / According to the Kyoto Protocol, planning an ecologically sustainable future is the greatest challenge of the 21st Century. Current patterns of energy resources and energy use are shown detrimental to the welfare of mankind in the long run. The integrity of essential natural systems is already at risk because of the climate change caused by the intense emission of greenhouse gases into the atmosphere. In this context, the Carbon Capture and Storage (CCS) technology is a promising activity that aims to reduce the emission of gases responsible by the greenhouse effect and climate change mitigation through CO2 capture, transport and storage in suitable geological formations (saline aquifers, coal reservoirs, oil and gas reservoirs). Therefore, inserted in this context, this dissertation has how objective analysis of the technical potential for carbon capture and geological sequestration of Espírito Santo onshore and offshore basin addressing amenable geologic environments to the application of CCS projects, phases that make up these projects, their investments and operational costs and the development of mathematical modeling for the calculations regarding the storage capability and calculation of estimated financial profitability along with its execution through the sale of extra oil produced by the advanced recovery technique of oil and the sale of carbon credits. For that, this project had how methodological strategy: the exploratory research and review of the literature on the subject, the collection of secondary data, via document analysis, and xx collecting primary data via interviews with experts and participation in national and international congress geared for the theme. Therefore, it is concluded that CCS projects are possible deployment in the state of Espírito Santo, this is because in addition to the geological structure of oil and gas reservoirs in the Espírito Santo basin contribute to good results (as, in most cases, are sandstone reservoirs with presence of seal rock), the potential of saline aquifers and the potential of hydrocarbon fields studied in this dissertation (Golfinho, Inhambú, Fazenda Alegre, Cação, Canapu, Cangoá, Peroá and Camarupim) deserve national recognition; however, the lack of maturity of the private and public sectors, with respect to the management of projects of this nature and their widespread use, prevents the advancement of such technologies in the state of Espírito Santo and therefore in Brazil.

CO2 global emissions exceed 30 Giga tonnes (Gt) per year, and the high atmospheric concentrations are detrimental to the environment. In spite of efforts to decrease emissions by sequestration (carbon capture and storage) and repurposing (use in fine chemicals synthesis and oil extraction), more than 98% of CO2 generated is released to the atmosphere. With emissions expected to increase, transforming CO2 to chemicals of high demand could be an alternative to decrease its atmospheric concentration. Transportation fuels represent 26% of the global energy consumption, making it an ideal end product that could match the scale of CO2 generation. The long-term goal of the study is to transform CO2 to liquid fuels closing a synthetic carbon cycle. Synthetic fuels, such as diesel and gasoline, can be produced from syngas (a combination of CO and H2) by Fischer Tropsch synthesis or methanol synthesis, respectively. Methanol can be turned into gasoline by MTO technologies. Technologies to make renewable hydrogen are already in existence, but CO is almost exclusively generated from methane. Due to the high stability of the CO2 molecule, its transformation is very energy intensive. Therefore, the current challenge is developing technologies for the conversion of CO2 to CO with a low energy requirement. The work in this dissertation describes the development of a recyclable, isothermal, low-temperature process for the conversion of CO2 to CO with high selectivity, called Reverse Water Gas Shift Chemical Looping (RWGS-CL). In this process, H2 is used to generate oxygen vacancies in a metal oxide bed. These vacancies then can be re-filled by one O atom from CO2, producing CO. Perovskites (ABO3) were used as the oxide material due to their high oxygen mobility and stability. They were synthesized by the Pechini sol-gel synthesis, and characterized with X-ray diffraction and surface area measurements. Mass spectrometry was used to evaluate the reducibility and re-oxidation abilities of the materials with temperature-programmed reduction and oxidation experiments. Cycles of RWGS-CL were performed in a packed bed reactor to study CO production rates. Different metal compositions on the A and B site of the oxide were tested. In all the studies, La and Sr were used on the A site because their combination is known to enhance oxygen vacancies formation and CO2 adsorption on the perovskites. The RWGS-CL was first demonstrated in a non-isothermal process at 500 °C for the H2-reduction and 850 °C for the CO2 conversion on a Co-based perovskite. This perovskite was too unstable for the H2 treatment. Addition of Fe to the perovskite enhanced its stability, and allowed for an isothermal and recyclable process at 550 °C with high selectivity towards CO. In an effort to decrease the operating temperature, Cu was incorporated to the structure. It was found that Cu addition inhibited CO formation and formed very unstable oxide materials. Preliminary studies show that application of this technology has the potential to significantly reduce CO2 emissions from captured flue gases (i.e. from power plants) or from concentrated CO2 (adsorbed from the atmosphere), while generating a high value chemical. This technology also has possible applications in space explorations, especially in environments like Mars atmosphere, which has high concentrations of atmospheric carbon dioxide.

Given the growing worldwide interest in fossil fuels on one hand and mitigation of climate change on the other hand, it is necessary to research into new technologies as Carbon Capture and Storage. This technology became a matter of interest as an option to diminish greenhouse gas emissions of power plants. It is essential to find out about the costs of Carbon Capture and Storage and expected future costs of power plants with CCS. Impact of this techology is not only in the sphere of capital and operational costs, but it also influences power plant efficiency and fuel consumption in negative way. Analysis of reductions in the costs of this technology as a result of learning-by-doing is observed on Experience Curves. This study observes influence of CCS on costs of mainly PC, IGCC and NGCC type of power plant. CCS technology has positive impact not only on environment, but it is possible to assess Enhanced Oil, Methane or Gas Recovery, which can partly offset costs of this technology.

Industries have faced challenges trying to lower carbon emissions and reach climate goals solely with energy efficiency and renewable energy sources but there are still some emissions that will not be mitigated by this. The purpose of this work has been to evaluate bio-energy with carbon capture and storage with co-combustion in a current study as a way to breach the gap and achieve net zero emissions on AstraZenecas production site Snäckviken. A carbon audit based on GHG Protocol has been performed to evaluate the total emissions at the site. Energy calculations were performed based on the possibilities of co-combustion with waste solvent and biofuel to produce process steam. With the flue gas characteristics for the combustion, calculations for a post combustion carbon capture plant using MEA solvent was made. An economic evaluation has been performed based on a reference plant and carbon captured for the current study. The results showed that the carbon capture lowered the emissions for the production site from 1 020 tons CO2 per year to - 2 400 tons CO2 at a cost of 1 360 SEK/tons CO2. The CO2 avoidance cost was high compared to other studies due to lower capacity. However, great savings could be m ade from handling the waste solvent on site instead of paying for the destruction of the waste. Therefore, a carbon capture plant could still be feasible for the current study.

Global energy demand is predicted to rise in the coming decades, necessitating a shift to renewable energy sources to mitigate greenhouse gas emissions. However, due to the inability to supply renewable energy around the clock, it is estimated that only by adding an important technology, carbon capture and storage (CCS), it could be possible to reduce 80% of the 1990s greenhouse gas emissions. CCS aims to reduce anthropogenic carbon emissions by capturing CO2 from flue gases, transporting, and permanently storing or reutilizing industrially. The CCS approach includes three technologies: post-combustion capture, pre-combustion capture, and oxyfuel combustion, with the latter being the emphasis of this thesis. Based on the case study of Mälarenergi’s Refused-derived waste-fired CHP plant, this thesis investigates the viability of converting existing non-fossil fueled CHP plants to oxyfuel combustion. A thorough technical investigation based on analyzing the impact of oxyfuel combustion on system performance was conducted through system modeling using a process simulator, Aspen plus. The model in this thesis considers the development of an air separation unit (ASU), a CHP plant, and a cryogenic CO2 purification unit (CPU). All of which are validated through calibration and comparison with real-world data and similar work. To investigate the influence of employing oxyfuel combustion on the generation of both heat and electricity, two different scenarios were comprised, including recirculating flue gas before and after flue gas condensation. In addition, an analysis of the oxygen purity was conducted to assess the most optimal parameters with the least impact on system performance. Moreover, a detailed eco- nomic assessment comprising the costs of integrating oxyfuel combustion was also conducted. The findings of this thesis show that integrating waste incineration CHP plants with oxyfuel combustion for CO2 capture entails promising features under the condition of 97% oxygen purity and a flue gas recirculation system taking place after flue gas condensation. This is owing to (i) modest imposed energy penalty of approximately 8.7%, (ii) high CO2 recovery ratio, around 92.4%, (iii) total investment cost of approximately 554 M$ during a 20-year lifetime, and (iv) cost of captured CO2 of around 76 $/ton. Aside from system modeling, this thesis pre- sents an overview of the current state-of-the-art technology on the different separation and capture mechanisms. It is important to highlight that the goal of this thesis is not to provide a comprehensive review but rather to present an overall picture of the maturity of the different mechanisms. The findings point to the cryogenic separation mechanism as the most mature technology for both oxygen production and capturing of CO2 during oxyfuel combustion.

<p>CO₂ concentration in the atmosphere poses a great threat to life on earth as we know it. The reduction of CO₂ concentration is key to avoid the critical turning point of 1.5^oC temperature increase highlighted by Intergovernmental Panel on Climate Change (IPCC). Gasification using CO₂ as reacting agent can potentially reduce the CO₂ concentration in the atmosphere. Naturally, biomass such as corn, uses great amounts of CO₂ for photosynthesis and produces O₂; hence, energy and fuel production using biomass can potentially be classified as carbon neutral. Moreover, if CO₂ is used as the gasifying agent, gasification can effectively be carbon-negative and collaborate to the reduction of CO2 in the atmosphere.</p> <p>The major setback of using CO₂ biomass gasification is the energy-intensive reaction between C + CO₂ -> 2CO. This reaction at atmospheric pressure and room temperature is heavily tilted towards producing char and CO2. The current investigation describes efforts to favor the right hand side of the reaction by using simple impregnation techniques and cost-effective catalysts to reduce the energy requirements of the reaction. Also, parameters such as pressure are explored to tilt the balance towards the production of CO. Corn stover is selected as the biomass for the present research due to its wide use and availability in the US.</p> <p>The results show that by using catalysts such as iron nitrate and sodium aluminate, the temperature required to achieve substantial char conversion is reduced. Also, increasing the pressure of the reactor, the temperature can be substantially decreased by 100 K and 150 K. The structure and chemical composition of the chars is studied to explain the differences in the reaction rate between chars. Further, chemical kinetics are calculated to compare the present work with previous work in the literature. Finally, data-driven analysis of the gasification data is explored. The appendices provide supplementary information on the application of deep learning to CO₂ recycling using turbulent flames and efforts to reduce the flame spread rate over a pool of Jet A by using Multi Walled Carbon Nanotubes (MWCNTS).</p>

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21129号 / 工博第4493号 / 新制||工||1698(附属図書館) / 京都大学大学院工学研究科化学工学専攻 / (主査)教授 宮原 稔, 教授 山本 量一, 教授 佐野 紀彰 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM