abstract: Mixed-ionic electronic conducting (MIEC) oxides have drawn much attention from researchers because of their potential in high temperature separation processes. Among many materials available, perovskite type and fluorite type oxides are the most studied for their excellent oxygen ion transport property. These oxides not only can be oxygen adsorbent or O2-permeable membranes themselves, but also can be incorporated with molten carbonate to form dual-phase membranes for CO2 separation. Oxygen sorption/desorption properties of perovskite oxides with and without oxygen vacancy were investigated first by thermogravimetric analysis (TGA) and fixed-bed experiments. The oxide with unique disorder-order phase transition during desorption exhibited an enhanced oxygen desorption rate during the TGA measurement but not in fixed-bed demonstrations. The difference in oxygen desorption rate is due to much higher oxygen partial pressure surrounding the sorbent during the fixed-bed oxygen desorption process, as revealed by X-ray diffraction (XRD) patterns of rapidly quenched samples. Research on using perovskite oxides as CO2-permeable dual-phase membranes was subsequently conducted. Two CO2-resistant MIEC perovskite ceramics, Pr0.6Sr0.4Co0.2Fe0.8 O3-δ (PSCF) and SrFe0.9Ta0.1O3-δ (SFT) were chosen as support materials for membrane synthesis. PSCF-molten carbonate (MC) and SFT-MC membranes were prepared for CO2-O2 counter-permeation. The geometric factors for the carbonate phase and ceramic phase were used to calculate the effective carbonate and oxygen ionic conductivity in the carbonate and ceramic phase. When tested in CO2-O2 counter-permeation set-up, CO2 flux showed negligible change, but O2 flux decreased by 10-32% compared with single-component permeation. With CO2 counter-permeation, the total oxygen permeation flux is higher than that without counter-permeation. A new concept of CO2-permselective membrane reactor for hydrogen production via steam reforming of methane (SRM) was demonstrated. The results of SRM in the membrane reactor confirm that in-situ CO2 removal effectively promotes water-gas shift conversion and thus enhances hydrogen yield. A modeling study was also conducted to assess the performance of the membrane reactor in high-pressure feed/vacuum sweep conditions, which were not carried out due to limitations in current membrane testing set-up. When 5 atm feed pressure and 10-3 atm sweep pressure were applied, the membrane reactor can produce over 99% hydrogen stream in simulation. / Dissertation/Thesis / Doctoral Dissertation Chemical Engineering 2020

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Les technologies de captage, transport et stockage du CO2 ont pour finalité de capter le CO2 issu des industries afin de le stocker géologiquement et ainsi, réduire l impact de ces activités sur le réchauffement climatique. L Axe-Seine (Paris Le Havre) est un territoire très industrialisé et fortement émetteur de CO2. Dans ce territoire, les décideurs locaux envisagent l utilisation des technologies de CTSC afin de réduire les émissions de gaz à effet de serre. L objectif de notre recherche est de comprendre les futurs possibles de ces technologies dans l Axe-Seine. Dans cette perspective, cette thèse analyse tout d'abord le fonctionnement des technologies de CTSC dans une approche de sociologie des sciences et des techniques et les promesses technoscientifiques initiales associées à ce dispositif technique. Ensuite, cette recherche examine les dynamiques socio-spatiales de la vallée de la Seine concernant l'environnement. Enfin, cette thèse par une exploration des récits relatifs aux technologies de CTSC par les promoteurs de ce dispositif technique et des parties prenantes locales, identifie les hybridations potentielles entre ce dispositif technique et les dynamiques socio-spatiales de l'Axe-Seine. Ainsi est-il possible de décrire les futurs possibles des technologies dans l'Axe-Seine. Par ailleurs, dans cette recherche nous questionnons également la place des sciences sociales au côté des sciences de la vie et de la matière dans la dynamique de l'innovation technologique. / Carbon Capture and Storage enables industrial facilities to capture their CO2 emissions in order to geologically store it and then reduce their impact on global warming. The Seine Waterway Axis (from Paris to Le Havre) counts a lot of industrial facilities emitting huge quantities of CO2. From 2006 local stakeholders of this territory are willing to develop CCS to a commercial scale in order to reduce CO2 emissions.In our research we aim to understand potential futures of CCS technology in the Seine Waterway Axis. In this Phd thesis we first analyse initial technoscientific promises related to Carbon Capture and Storage in using Science and Technology Studies theoretical framework. Then we focus on the Seine Waterway Axis territorial dynamics regarding sustainable development. Finnaly, we focus on narratives related to Carbon Capture and Storage in the Seine Waterway Axis in order to identify hybridations between CCS implementations and territorial dynamics. These cross analysis will enable us to describe potential future of CCS establishment in the Seine Waterway Axis.

The reduction of greenhouse gas emissions is important to keep climate change under control. One of the largest CO2 emitters of the Swedish industries is the steel industry. This is, among others, due to the need of heat treatments and reheating processes depending on high temperatures and fossil fuels. The business organisation Jernkontoret and their department for energy and furnace technique is working towards reducing the emissions for these processes and one area of research is the carboncapture and storage (CCS) techniques. This report aims to give an overview of existing and emerging CCS techniques applicable for the reheating and heat treating furnaces, along with evaluating one post-combustion carbon capture technique for different cases provided by some involved companies. The carbon capture technique investigated in this project can be divided into three main sections; Oxyfuel combustion, pre-combustion and post-combustion capture. Oxyfuel relies on the usage of pure oxygen instead of air for the combustion of the fuel, this gives a high CO2 concentration in the flue gas (80-98%). Concentrations below 95% require further purification before compression and transportation to storage. Using pre-combustion capture the CO2 is removed before the combustion, this can be done by reformingthe used fossil fuel to a syngas (a gas with a high H2 and CO concentrations). The CO2 is formed by passing the syngas through a water-gas shift, which also increases the H2 concentration further. The CO2 can then be removed relying on reversible chemical reactions or the affinity between the CO2 and an absorbent. The post-combustion carbon capture also relies on reversible chemical reactions or affinity to an absorption medium, usually an amine solvent. The bond is then broken in the desorption unit, creating a pure CO2 stream and a reusable absorbent. The case studies were done only for a post-combustion capture process with a MEA-water solvent (20%) as the absorption medium. The simulation program Aspen Plus was used both for the technicaland economical values, executed by the PhD student Nan Wang at LTU. The values were interpolated/extrapolated nonlinear for each given case. Six different cases were given by four companies, four conventional furnaces and two oxyfuel furnaces. Evaluations for the oxyfuel furnaces were excluded, due to big differences between the model and case values and since the technique evaluated is not implementedat oxyfuel plants. The evaluations done for the conventional furnace cases gave a total cost of between 86 - 126 $/tonne captured CO2. This has to be viewed as a high cost investment even without having a full economic evaluation regarding cost for transportation and storage included.

The industrial sector is one of the largest emitters of CO2 and a great potential for retrofitting with carbon capture systems. In this work the performance of a palladium-based membrane reactor at 400°C and operating pressures between 100-400 kPa have been studied in terms of methane conversion, hydrogen recovery, hydrogen purity, and CO2 emission. It is found that the MR has the potential to produce high purity hydrogen while the methane conversion values could be as high as 40% at very moderate operating conditions and without using any sweep gases. The H2 permeation and separation properties of two Pd-based composite membranes were evaluated and compared at 400 °C and at a pressure range of 150 kPa to 600 kPa. One membrane was characterized by an approximately 8 μm-thick palladium (Pd)-gold (Au) layer deposited on an asymmetric microporous Al2O3 substrate; the other membrane consisted of an approximately 11 μm-thick pure palladium layer deposited on a yttria-stabilized zirconia (YSZ) support. At 400 °C and with a trans-membrane pressure of 50 kPa, the membranes showed a H2 permeance of 8.42 × 10−4 mol/m2·s·Pa0.5 and 2.54 × 10−5 mol/m2·s·Pa0.7 for Pd-Au and Pd membranes, respectively. Pd-Au membrane showed infinite ideal selectivity to H2 with respect to He and Ar at 400 °C and a trans-membrane pressure of 50 kPa, while the ideal selectivities for the Pd membrane under the same operating conditions were much lower. Furthermore, the permeation tests for ternary and quaternary mixtures of H2, CO, CO2, CH4, and H2O were conducted on the Pd/YSZ membrane. The H2 permeating flux decreased at the conclusion of the permeation tests for all mixtures. This decline however, was not permanent, i.e., H2 permeation was restored to its initial value after treating the membrane with H2 for a maximum of 7 h. The effects of gas hourly space velocity (GHSV) and the steam-to-carbon (S/C) ratio on H2 permeation were also investigated using simulated steam methane reforming mixtures. It was found that H2 permeation is highest at the greatest GHSV, due to a decline in the concentration polarization effect. Variations in S/C ratio however, showed no significant effect on the H2 permeation. The permeation characteristics for the Pd/YSZ membrane were also investigated at temperatures ranging from 350 to 400 °C. The pre-exponential factor and apparent activation energy were found to be 5.66 × 10−4 mol/m2·s·Pa0.7 and 12.8 kJ/mol, respectively. Scanning Electron Microscope (SEM) and X-ray diffraction (XRD) analyses were performed on both pristine and used membranes, and no strong evidence of the formation of Pd-O or any other undesirable phases was observed. The permeation tests with pure hydrogen and inert gases indicate that the MR is highly selective toward hydrogen and the produced hydrogen is an ultrahigh purity grade. The carbon capture experiments in the work consists of dehydrating the retentate stream and redirecting it to a 13X packed bed before analyzing the stream via mass spectrometry. The carbon capture studies reveal that approximately 5.96 mmole CO2 (or 262.25 mg of CO2)can be captured per g of 13X. In this study, SEM-EDS, and XRD technics have been used to characterize the crystallography and morphology of the membrane surface. These material characterization techniques reveal that the surface of the membrane has gone through significant oxidation during the steam methane reforming reaction, although this oxidation is only limited to the few nanometers of depth through the surface of the palladium membrane.

Biomass combustion can be seen as CO2 neutral, thereby biomass combustion plants can have negative CO2 emissions if retrofitted with post combustion capture (PCC) technology using liquid absorbents. Monoethanolamine (MEA) has been used for carbon capture in coal combustion plants but are not suitable for use in biomass combustion plants due to corrosion and high solvent regeneration cost. Instead, the hot potassium carbonate (HPC) process using potassium carbonate (K2CO3) as absorbent show better attributes in these aspects. Although, K2CO3 has slow reaction kinetics with CO2 which need to be improved using promoters. Piperazine is the most tested promoter but are hazardous to humans. Recent research has revealed promising alternatives, among these different amino acid salts such as glycine, proline, and isonipecotic acid which are chemically benign. Biomass flue gas composition vary depending on the biomass fuel characteristics. How this affects the degradation and potential formation of hazardous substances need to be studied further. Biomass combustion plants are generally equipped with flue gas condensation systems, making retrofitting more feasible due to increased system flexibility and energy recovery options. The operation costs of carbon capture and sequestration (CCS) in biomass combustion plants need to be monitored to optimize the plant revenue. To make implementation of HPC in biomass combustion plants a reality, piperazine should be used as promoter. Meanwhile, research should focus on improving the absorption rate in HPC process with more chemically safe promoters.

Fluids play a vital role in essentially all geologic environments and processes, and are the principal media of heat and mass transfer in the Earth. The properties of geologic fluids can be diverse, as fluids occur at conditions ranging from ambient temperatures and pressures at Earth's surface, to extreme temperatures and pressures in Earth's deep interior. Regardless the wide ranges of conditions at which geologic fluids occur, fluid properties are described and governed by the same fundamental thermodynamic relationships. Thus, application of thermodynamic principles and methods allows us to decipher the properties and roles of geologic fluids, to help understand geologic processes. Fluid inclusions in minerals provide one of the best available tools to study the compositions of geological fluids. Compositions of fluid inclusions can be determined from microthermometric measurements, based on the vapor-saturated liquidus conditions of model chemical systems, or by various microanalytical techniques. The vaporsaturated liquidus relations of the system H2O-NaCl-CaCl2 have been modeled to allow estimation of fluid inclusion compositions by either microthermometric or microanalytical methods. Carbon capture and storage (CCS) in deep saline formations represents one option for reducing anthropogenic CO2 emissions into Earth's atmosphere. Availability of storage volume in deep saline formations is a significant component of injection and storage planning. Investigation of the volumetric properties of CO2, brine and CO2-saturated brine reveals that storage volume requirements are minimized when CO2 dissolves into brine. These results suggest that a protocol involving brine extraction, CO2 dissolution and re-injection may optimize CCS in deep saline formations. Numerical modeling of quartz dissolution and precipitation in a sub-seafloor hydrothermal system was used to understand the role of fluid-phase immiscibility ("boiling") on quartz-fluid interactions, and to predict where in the system quartz could deposit and trap fluid inclusions. The spatial distribution of zones of quartz dissolution and precipitation is complex, owing to the many inter-related factors controlling quartz solubility. Immiscibility exerts a strong control over the occurrence of quartz precipitation in the deeper regions of fluid circulation. / Ph. D.

Recent studies report rapid corrosion of metals and carbonation of minerals in contact with H2O-saturated (or nearly saturated) CO2. One explanation for this behavior is that addition of small amounts of H2O to CO2 leads to significant ionization within the fluid (analogous to corrosion in aqueous fluids). The extent of ionization in the bulk CO2 fluid was determined using a flow-through conductivity cell capable of analyzing very dilute solutions. Experiments were conducted from 25 to 200"C and 25 to 200 bar with H2O concentrations up to ~1650 ppmw. In all experiments, conductivities <10 nS/cm were obtained, indicating that the solution is essentially ion-free. This observation suggests that mobile ions are not present in the bulk CO2--rich fluid, and that the observed corrosion and carbonation reactions are not the result of ionization in the bulk fluid. / Master of Science

Metal organic frameworks (MOFs) is a quite recently discovered porous material group which shows potential in many different areas. One of these areas is carbon capture; the framework structure of the porous materials allows gas molecules to adsorb to the surface of the pores. MOFs are conventionally synthesised at high temperatures and with hazardous solvents. The goal of this projectwas to synthesise highly porous MOFs at room temperature with water as the main solvent, using environmentally friendly and non-hazardous precursors. As well as the room temperature synthesis, conventional synthesis methods were used with the same precursors as comparison. The materials were characterised with X-ray diffraction, thermogravimetrical methods and IR-spectroscopy. To assess the porosity of the materials, gas adsorption evaluation was performed with CO2, N2, SF6, and CH4 at 20⁰C. In the end, three novel porous magnesium-based materials and one zirconium-based material were successfully synthesised. One of the magnesium-based materials showed a moderately high CO2 adsorption (2.38mmol/g), and could be synthesised at room temperature. The zirconium-based material showed a remarkably high selectivity (17.7) for SF6 over N2 and a high surface area (550m2/g)

Abstract: Global decarbonization requires addressing local challenges and advancing appropriate technologies. In this dissertation, an investigation of appropriate carbon capture technologies for CO2 capture from heavy fuel oil (HFO) fired power plants, common locally, is presented. Two emerging technologies are considered, chemical looping combustion (CLC) and calcium looping (CaL). In a preliminary study, CLC and CaL implementation at an HFO-fired power plant are modeled using Aspen software, and based on the results, CaL is selected for further experimental investigation. Briefly, CaL is a high temperature separation process that utilizes limestone-derived CaO tosimultaneously concentrate CO2 and capture SO2 from flue gas. The solid CaO particles are cycled between carbonation and calcination, CaO + CO2 ⇋ CaCO3, in a dual fluidized bed system and experience capture capacity decay with cycling. Structurally distinct limestones were procured from the two geologic regions where limestone is mined in Saudi Arabia. Using bubbling fluidized bed reactor systems, the capture performance of these two limestones, and a German limestone of known performance, were compared. The combined and individual influence of flue gas H2O and SO2 content, the influence of textural changes caused by sequential calcination/carbonation cycles, and the impact of CaSO4 accumulation on the sorbents’ capture performance were examined. It was discovered that metamorphosed limestone-derived sorbents exhibit atypical capture behavior: flue gas H2O negatively influences CO2 capture performance, while limited sulfation can positively influence CO2 capture. The morphological characteristics influencing sorbent capture behavior were examined using imaging and material characterization tools, and a detailed discussion is presented. Saudi Arabian limestones’ deactivation rates were examined by thermogravimetric analysis. A quantitative correlation describing sulfation deactivation was developed. The validity of amending the conventional semi-empirical sorbent deactivation model with the novel correlation was supported by subsequent pilot scale (20 kWth) experiments. Solving process mass and energy balances, reasonable limits on operating parameters for CaL implementation at HFO-fired power plants were calculated. The influence of power plant configuration, carbonator design, and limestone source on power plant energy efficiency are considered and a discussion is presented. Finally a commentary on the potential of this technology for local implementation and required future work is presented.