Two of the hottest areas in porous materials research in the last decade have been in energy storage, mainly hydrogen and methane, and in carbon capture and sequestration (CCS). Although these topics are intricately linked in terms of our future energy landscape, the specific materials needed to solve these problems must have significantly different properties. High pressure gas storage is most often linked with high surface areas and pore volumes, while carbon capture sorbents require high sorption enthalpies to achieve the needed selectivity. The latter typically involves separating CO2 from mixed gas streams of mostly nitrogen via a temperature swing adsorption (TSA) process. Much of the excitement has arisen because of the potential of metal-organic frameworks (MOFs) and porous polymer networks (PPNs). Both classes of materials have extremely high surface areas (upwards of 4000 m2/g) and can be modified to have specific physical properties, thus enabling high performance materials for targeted applications. This dissertation focuses on the synthesis and characterization of these novel materials for both applications by tuning framework topologies, composition, and surface properties. Specifically, two routes to synthesize a single molecule trap (SMT) highlight the flexibility of MOF design and ability to tune a framework to interact with specifically one guest molecule; computational and experimental evidence of the binding mechanism are shown as well. Furthermore, eight PPNs are synthesized and characterized for post-combustion carbon capture and direct air capture applications. In addition a high-throughput model, grounded in thermodynamics, to calculate the energy penalty associated with the carbon capture step is presented in order to evaluate all materials for TSA applications provide a comparison to the state of the art capture technologies. This includes results of working capacity and energy calculations to determine parasitic loads (per ton of CO2 captured) from readily available experimental data of any material (adsorption isotherms and heat capacities) using a few simple equations. Through various systematic investigations, trends are analyzed to form structure property relationships that will aid future material development.

Submitted by TIARA MORAES GUIMARÃES null (tiaraguimaraes@yahoo.com.br) on 2016-04-12T20:05:10Z No. of bitstreams: 1 VERSÃO FINAL - DISSERTAÇÃO.pdf: 2061074 bytes, checksum: cd312ff121220dcddbf2d2a217e78cfd (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-04-15T13:36:41Z (GMT) No. of bitstreams: 1 guimaraes_tm_me_bot.pdf: 2061074 bytes, checksum: cd312ff121220dcddbf2d2a217e78cfd (MD5) / Made available in DSpace on 2016-04-15T13:36:41Z (GMT). No. of bitstreams: 1 guimaraes_tm_me_bot.pdf: 2061074 bytes, checksum: cd312ff121220dcddbf2d2a217e78cfd (MD5) Previous issue date: 2016-02-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A calagem destaca-se entre as práticas agrícolas mais eficientes em resolver os problemas relacionados à acidez do solo, entretanto resulta em emissões de gases de efeito estufa (GEE), principalmente CO2. É possível que o aumento no desenvolvimento radicular no perfil do solo e da biomassa aérea, decorrente da aplicação de corretivos de acidez, como o calcário, e de condicionadores, como o gesso agrícola, promova maior retorno de C ao solo na forma de resíduos, o que pode favorecer a fixação do CO2 da atmosfera no solo. Desta forma objetivou-se avaliar a emissão de gases de efeito estufa, bem como possíveis alterações no estoque de carbono do solo, em função da correção da acidez do solo utilizando calcário e gesso em sistema semeadura direta (SSD), além da emissão de carbono equivalente por unidade de massa de grãos produzida pelo feijoeiro. O presente trabalho é parte de um experimento de longa duração, instalado em 2002/03, na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas da UNESP, em Botucatu (SP). Após a colheita do trigo em julho de 2014 semeou-se em outubro do mesmo ano milheto para produção de palha, e posteriormente a dessecação da área foi realizada a semeadura da cultura do feijão, no início de dezembro de 2014. O delineamento experimental foi em blocos casualizados no esquema de parcelas subdivididas, com 4 repetições. As parcelas foram constituídas por quatro doses de calcário (0, 1000, 2000 e 4000 kg ha-1) e as subparcelas por duas doses de gesso agrícola (0 e 2100 kg ha-1). Foram realizadas as seguintes avaliações: carbono orgânico total e nitrogênio total do solo, estoque de C e N do solo, C e N da biomassa microbiana do solo e teor de C e N na matéria seca. Foram determinados os fluxos de CO2; CH4 e N2O por meio de câmaras estáticas, nos períodos 1; 3; 5; 8; 15; 30 dias após a semeadura do milheto e 1; 3; 5; 8; 15; 21; 30; 60; 90 dias após a semeadura do feijão, totalizando 15 períodos de amostragens. Observou-se que as maiores emissões de CO2 estão relacionadas com o teor de CBMS, que é um indicativo de imobilização/mineralização de C pelos microrganismos. Sendo assim quanto maior o teor de CBMS, maior a imobilização de nutrientes no solo, maior a taxa de respiração e consequentemente maior emissão de CO2. A aplicação de gesso agrícola aumenta a oxidação de CH4 no solo, favorecendo assim a mitigação de GEE. A emissão de N2O está relacionada com a maior acidificação do solo e com o teor de água no solo. / Liming stands out among the most efficient agricultural practices in solving the soil acidity-related problems, however results in emissions of greenhouse gases (GHGs), particularly CO2. It is possible that the increase in root development in the soil profile and biomass, resulting from the application of soil correctives such as limestone and conditioners such as agricultural gypsum, promote greater return of C to the soil in the form of waste, which can promote the fixation of CO2 from the atmosphere into the soil. Thus aimed to evaluate the emission of greenhouse gases, and possible changes in the stock of soil carbon, depending on soil acidity correction using lime and phosphogypsum in no-tillage, in addition to carbon emissions equivalent per unit mass of grain produced by bean plants. This work is part of a long-term experiment, installed in 2002/03, at Lageado Experimental Farm, belonging to the College of Agricultural Sciences - UNESP in Botucatu (SP). After the wheat harvest in July 2014 the millet was sown in October of that year to produce straw, and after the desiccation of the area its was held the sowing of bean crop in early December 2014. The experimental design was performed in randomized block, in a split plot scheme, with four repetitions. The plots consisted of four liming rates (0, 1000, 2000 and 4000 kg ha-1) and the subplots of two rates of phosphogypsum (0 to 2100 kg ha-1). The following evaluations were performed: total organic carbon and total soil nitrogen, stock of C and N of the soil, C and N microbial biomass of the soil and the contents of C and N in the dry matter. It were determined the CO2 streams; CH4 and N2O by static chambers in the periods 1; 3; 5; 8; 15; 30 days after sowing of millet and 1; 3; 5; 8; 15; 30; 60; 90 days after sowing the beans, totaling 15 sampling periods. It was observed that the higher CO2 emissions are related to the CMBS content, which is indicative of immobilization / mineralization of the C by the microorganisms. Thus higher the CMBS content, higher the immobilization of the nutrients in the soil, higher the rate of breathing and consequently higher emissions of CO2. The application of gypsum increases the CH4 oxidation in the soil, favoring the mitigation of greenhouse gases. The N2O emission is related to the higher soil acidification and the water content in the soil.

Submitted by Caio Felipe de Paula Santos null (38626554826) on 2016-04-20T17:19:28Z No. of bitstreams: 1 Dissertação_final.pdf: 650643 bytes, checksum: 4c9c3b09b961790fcddd0d2c996feba9 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-04-26T17:53:46Z (GMT) No. of bitstreams: 1 santos_cfp_me_guara.pdf: 650643 bytes, checksum: 4c9c3b09b961790fcddd0d2c996feba9 (MD5) / Made available in DSpace on 2016-04-26T17:53:46Z (GMT). No. of bitstreams: 1 santos_cfp_me_guara.pdf: 650643 bytes, checksum: 4c9c3b09b961790fcddd0d2c996feba9 (MD5) Previous issue date: 2016-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A geração de energia elétrica em usinas termoelétricas de ciclo combinado tem se mostrado muito importante para o Brasil apesar de operar com custo maior do que a geração através de hidroelétricas. Neste trabalho, foram realizadas análises termoeconômica e ecológica, baseadas nos princípios da Termodinâmica (energia e exergia), aplicados em usina termoelétrica de ciclo combinado de 500 MW. Para este trabalho foram consideradas duas configurações para a planta: a primeira configuração é a padrão (sem considerar equipamento de redução de emissão de CO2), e a segunda que considera a implementação do processo de captura, armazenamento e compressão de CO2 (CAC). O principal objetivo do trabalho é estudar e comparara as diferenças nas eficiências termodinâmicas e ecológicas da planta (operando nas duas condições) e as alterações nos custos de produção de energia elétrica gerada, em vista da instalação do processo de CAC. / The Electric Power Generation in combined cycle power plants has been very important for Brazil despite having a higher cost than the generation through hydropower plants. In this work, there were performed thermeconomical and ecological analyzes, based on thermodynamic principles (energy and exergy) in a 500 MW combined cycle power plant. For this work there were considered two settings for this plant: first a standard configuration (without to consider equipments for CO2 emission reduction), and the second considering the implementation of a process of capture, storage and compression of carbon dioxide (CSC). The main objective of this analysis is to study and compare the differences in thermodynamic and ecological efficiencies (operating in both conditions) and the alterations in the electrical energy cost, in view of the installation of the CSC process.

This thesis’s main focus is a CO2 capture technology known as chemical looping combustion (CLC). The technology is a novel form of combustion and fuel processing that can be applied to gas, solid and liquid fuels. By using two interconnected fluidised-bed reactors, with a bed material capable of transferring oxygen from air to the fuel, a stream of almost pure CO2 can be produced. This stream is undiluted with nitrogen and is produced without any direct process efficiency loss from the overall combustion process. The heart of the process is the oxygen carrier bed material, which transfers oxygen from an air to fuel reactor for the conversion of the fuel. Oxygen carrier materials and their production should be of low relative cost for use in large-scale systems. The first part of this research centres on development and investigative studies conducted to assess the use of low-cost materials as oxygen carriers and as supports. Mixed-oxide oxygen carriers of modified manganese ore and iron ore were produced by impregnation. While copper (II) oxide supported on alumina cement and CaO have been produced by pelletisation. These oxygen carriers were investigated for their ability to convert gaseous fuels in a lab-scale fluidised bed, and characterised for their mechanical and chemical suitability in the CLC process. The modified ores and pelletised copper-based oxygen carriers’ mechanical properties were enhanced by their production methods and in the case of the modified iron ore, significant oxygen uncoupling was observed. The copper-based oxygen carriers particularly those containing alumina cement showed high conversion rates of gaseous fuels and improved mechanical stability. The second part of this research thesis focuses on the design philosophy, commissioning and operation of a dual-fast bed chemical looping pilot reactor. Based on the operational experience, recommendations for modifications to the CLC system are discussed. In support, a parallel hydrodynamic investigation has been conducted to validate control and operational strategies for the newlydesigned reactor system. It was determined that the two fast bed risers share similar density and pressure profiles. Stable global circulation rate is flexible and could be maintained despite being pneumatically controlled. Reactor-reactor leakage via the loop-seals is sensitive to loop seal bed-height, and inlet fluid velocity but can be maintained as such to ensure no leakage is encountered.

Adsorption in porous materials is a promising technology for CO2 capture and storage. Particularly important applications are adsorption separation of streams associated with the fossil fuel power plants operation, as well as natural gas sweetening. High surface area activated carbons are a promising family of materials for these applications, especially in the high pressure regimes. As the streams under consideration are generally multi-component mixtures, development and optimization of adsorption processes for their separation would substantially benefit from predictive simulation models. In this project we combine experimental data and molecular simulations to systematically develop a model for a high surface area carbon material, taking activated carbon Maxsorb MSC-30 as a reference. Our study starts from the application of the well-established slit pore model, and then evolves through the development of a more realistic model, based on a random packing of small graphitic fragments. In the construction of the model, we introduce a number of constraints, such as the value of the accessible surface area, concentration of the surface groups and pore volume, to bring the properties of the model structure close to the reference porous material. Once a plausible model is developed, its properties are further tuned through comparison between simulated and experimental results for carbon dioxide and methane. The model is then validated by predictions for the same species at different conditions and by prediction of other species involved in the carbon capture processes. The model is applied to simulate the separations involved in pre and post combustion capture processes and sweetening of sour natural gas, using realistic conditions and compositions for the multicomponent mixtures. Finally, it is used to explore the effect of water in pre and post combustion separations.

Carbon capture and storage technologies (CCS) are expected to play a key role in the future energy matrix. Different gas separation processes are under investigation with the purpose of becoming a more economical alternative than solvent based post combustion configurations. Previous works have proved that pressure swing adsorption (PSA) cycles manage to reach similar carbon capture targets than conventional amine process but with approx. a 50% lower specific energy consumption when they are applied at lab scale. These encouraging results suggest that research must be undertaken to study the feasibility of this technology at a low to medium power plant scale. The simulation of PSA cycles is a computationally challenging and time consuming task that requires as well a large set of experimentally measured data as input parameters. The assumption of Equilibrium Theory reduces the amount of empirically determined input variables that are necessary for modelling adsorption dynamics as well as enabling a simpler code implementation for the simulators. As part of this work, an Equilibrium Theory PSA cycle solver (Esim) was developed, the novel tool enables the quantification of the thermodynamic limit for a given PSA cycle allowing as well a pre-selection of promising operating conditions and configurations (high separation efficiency) for further investigation by using full governing equation based software The tool presented in this thesis is able to simulate multi-transition adsorption systems that obey any kind of equilibrium isotherm function without modifying its main code. The second part of this work is devoted to the design, simulation and optimisation of two stage two bed Skarmstrom PSA cycles to be applied as a pre-combustion process in a biomass gasification CHP plant. Simulations were carried out employing an in house software (CySim) in which full governing equations have been implemented. An accurate analysis of the operating conditions and cycle configurations was undertaken in order to improve the performance of the carbon capture unit. It was estimated that the energy penalty associated with the incorporation of the adsorptive pre combustion process was lower for a conventional post combustion solvent unit, leading as well to lower specific energy consumption per unit of captured CO2 and higher overall efficiencies for the CHP plant with installed pre-combustion PSA cycles. This work is pioneer in its kind as far as modelling, simulation, optimisation and integration of PSA units in energy industries is concerned and its results are expected to contribute to the deployment of this technology in the future energy matrix.

Utilisation of biomass resources and CO2 abatement systems in currently exploited fossil resource based energy systems are the key strategies in resolving energy sustainability issue and combating against global climate change. These strategies are affected by high energy penalty and high investment. Therefore, it is imperative to assess the viability of these energy systems and further identify niche problem areas associated with energy efficiency and economic performance improvement. The current research work has two parts. The first part presents techno-economic investigation of thermochemical conversion of biomass into the production of fuels (Fischer-Tropsch liquid or methanol) and electricity. The work encompasses centralised bio-oil integrated gasification plant, assuming that the bio-oil is supplied from distributed pyrolysis plant. Bio-oil is a high energy density liquid derived from biomass fast pyrolysis process, providing advantages in transport and storage. Various bio-oil based integrated gasification system configurations were studied. The configurations were varied based on oxygen supply units, once-through and full conversion configurations and a range of capacities from small to large scale. The second part of this thesis considers integration of various CO2 abatement strategies in coal integrated gasification systems. The CO2 abatement strategies under consideration include CO2 capture and storage, CO2 capture and reuse as well as CO2 reuse from flue gas. These facilities are integrated into cogeneration or polygeneration systems. The cogeneration concept refers to the production of combined heat and power while polygeneration concept is an integrated system converting one or more feedstocks into three or more products. Polygeneration is advocated in this work attributed to its high efficiency and lower emission. Furthermore, it can generate a balanced set of products consisting of fuels, electricity and chemicals. It is regarded as a promising way of addressing the future rapidly growing energy demands. A holistic approach using systematic analytical frameworks comprising simulation modelling, process integration and economic analysis has been developed and adopted consistently throughout the study for the techno-economic performance evaluation of decarbonised fossil and bio-oil based systems. Important design methodology, sensitivity analysis of process parameters and process system modifications are proposed. These are to enhance the efficiency as well as lower the economic and environmental impacts of polygeneration systems. A shortcut methodology has also been developed as a decision-making tool for effective selection from a portfolio of CO2 abatement options and integrated systems. Critical and comprehensive analyses of all the systems under considerations are presented. These embrace the impact of carbon tax, product price evaluation and recommendations for sustainability of low carbon energy systems.

Motivated by the role of decarbonizing the electric power sector to mitigate climate change, I assess the economic and environmental merits of three key technologies for decarbonizing the electric power sector across four chapters in this thesis. These chapters explore how adding flexibility to power plants equipped with carbon capture and sequestration (CCS) affects system costs and carbon dioxide (CO2) emissions, how grid-scale electricity storage affects system CO2 emissions as a power system decarbonizes, and how distributed solar photovoltaic (distributed PV) electricity generation suppresses wholesale electricity prices. In each chapter, I address these questions through a combination of power system optimization, statistics, and techno-economic analysis, and tie my findings to policy implications. In Chapter 2, I compare the cost-effectiveness of “flexible” CCS retrofits to other compliance strategies with the U.S. Clean Power Plan (CPP) and a hypothetical stronger CPP. Relative to “normal” CCS, “flexible” CCS retrofits include solvent storage that allows the generator to temporarily eliminate the CCS parasitic load and increase the generator’s net efficiency, capacity, and ramp rate. Using a unit commitment and economic dispatch (UCED) model, I find that flexible CCS achieves more cost-effective emissions reductions than normal CCS under the CPP and stronger CPP, but that flexible CCS is less cost-effective than other compliance strategies under both reduction targets. In Chapter 3, I conduct a detailed comparison of how flexible versus normal CCS retrofits affect total system costs and CO2 emissions under a moderate and strong CO2 emission limit. Given that a key benefit of flexible CCS relative to normal CCS is increased reserve provision, I break total system costs into generation, reserve, and CCS capital costs. Using a UCED model, I find that flexible CCS retrofits reduce total system costs relative to normal CCS retrofits under both emission limits. Furthermore, 40-80% of these cost reductions come from reserve cost reductions. Accounting for costs and CO2 emissions, though, flexible CCS poses a trade-off to policymakers under the moderate emission limit, as flexible CCS increases system CO2 emissions relative to normal CCS. No such trade-off exists under the stronger emission limit, as flexible CCS reduces system CO2 emissions and costs relative to normal CCS. In Chapter 4, I quantify how storage affects operational CO2 emissions as a power system decarbonizes under a moderate and strong CO2 emission limit through 2045. In so doing, I aim to better understand how storage transitions from increasing CO2 emissions in historic U.S. systems to enabling deeply decarbonized systems. Additionally, under each target I compare how storage affects CO2 emissions when participating in only energy, only reserve, and energy and reserve markets. Using a capacity expansion (CE) model to forecast fleet changes through 2045 and a UCED model to quantify how storage affects system CO2 emissions, I find that storage quickly transitions from increasing to decreasing CO2 emissions under the moderate and strong emission limits. Whether storage provides only energy, only reserves, or energy and reserves drives large differences in the magnitude, but not the direction, of the effect of storage on CO2 emissions. In Chapter 5, I quantify a benefit of distributed photovoltaic (PV) generation often overlooked by value of solar studies, namely the market price response. By displacing high-cost marginal generators, distributed PV generation reduces wholesale electricity prices, which in turn reduces utilities’ energy procurement costs. Using 2013 through 2015 data from California including a database of all distributed PV systems in the three California investor owned utilities, we estimate historic hourly distributed PV generation in California, then link that generation to reduced wholesale electricity prices via linear regression. From 2013 through 2015, we find that distributed PV suppressed historic median hourly LMPs by up to $2.7-3.1/MWh, yielding avoided costs of up to $650-730 million. These avoided costs are smaller than but on the order of other avoided costs commonly included in value of solar studies, so merit inclusion in future studies to properly value distributed PV.

Climate change is a risk issue of global proportions. Human health and environmental impacts are anticipated from hazards associated with changes in temperature and precipitation regimes, and climate extremes. Increased natural hazards include storms and flooding, extreme heat, drought, and wildfires. Reduced food and water quality and quantity, reduced air quality, new geographic range of infectious diseases, and increased exposure to ultra-violet radiation are also predicted. In order to make a measurable contribution to reducing carbon dioxide emissions at point source fossil fuel and industrial process sites that contribute to climate change, estimates suggest that up to 3,000 dedicated large scale carbon capture and geological sequestration (CCS) projects will be necessary by 2050. Integrated projects include carbon dioxide capture; compression into a supercritical stream; transport, most often by pipeline; deep injection at wellheads; and sequestration in suitable saline aquifer geological formations, usually 800 metres or more below the earth’s surface. In implementing CCS as part of an overall climate change mitigation strategy, it is important to note that population health and environmental risks are associated with each of these value chain components of integrated projects. Based on an assessment of existing regulatory and non-regulatory guidance for risk assessment/risk management (RA/RM), an analysis of the application, assessment, and approval process for four large scale Canadian projects, and findings from a structured expert elicitation focused on hazard and risk issues in injection and storage and risk management of low probability high impact events, this research developed an Integrated Risk Management Framework (IRMF) for CCS in the Canadian context. The IRMF is a step-wise systematic process for RA/RM during the life of a project, including engagement with wide ranging government and non-government partners that would contribute to a determination of acceptable risk and risk control options. The execution of the IRMF is an intervention that could reduce local hazards and associated risks in terms of likelihood and consequence, as well as identify and document risk management that could underpin broad acceptance of CCS as a climate change mitigation technology. This would thereby also have an important part in protecting global population health and wellbeing in the long term. Indeed, diverse stakeholders could be unforgiving if hazard assessment and risk management in CCS is considered insufficient, leading to ‘pushback’ that could affect future implementation scenarios. On the other hand, RA/RM done right could favourably impact public perception of CCS, in turn instilling confidence, public acceptance, and ongoing support for the benefit of populations worldwide. This thesis is composed of an introduction to the research problem, including a population health conceptual framework for the IRMF, followed by five manuscripts, and concluding with a discussion about other barriers to CCS project development, and a risk management policy scenario for both the present time and during the 2017-2030 implementation period.

Adverse changes in the Earth's climate are thought to be due to the output of carbon dioxide from power stations. This has led to the development of many new materials to remove CO2 from these gas streams. Polymers of intrinsic microporosity (PIMs) are a novel class of polymers that are rigid with sites of contortion. These properties result in inefficient packing and so lead to large pore volumes and high surface areas. The inclusion of Tröger’s base, a contortion site made up of two nitrogen atoms, is thought to lead to increased uptake of CO2. The combination of electrostatic interactions with strong van der Waals forces should interact favourable with the quadrupole moment of CO2.Here a molecular simulation study of a selection of these polymers is presented. The study begins by developing a quick screening method on single polymer chains. This shows that the high surface area and adsorption affinity are a result of the contorted nature of PIMs along with the inclusion of groups such as Tröger’s base.The creation of atomistic models that reproduce the space packing ability of these polymers is also explored. Methods developed for PIMs in literature are investigated along with a new method developed during this study. GCMC simulations are then used to investigate the adsorption of CO2. In this study it is seen that that these polymers possess a well percolated network of both ultramicropores and supermicropores with a significant fraction of these pores being close to the kinetic diameter of CO 2. It is posited that these pores may be the result of the inclusion of Tröger’s base. It is also shown that this produces a particularly favourable site for adsorption. The phenomenon of swelling as a result of CO2 adsorption is also investigated using a variety of methods that make use of the output from the GCMC simulations. It was found that swelling is negligible for pressures of up to 1 bar. This result is important as swelling in the polymer can lead to a reduction in selectivity and an increase in permeability, which can affect the overall material’s performance.