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1
Bala, Shashi. „Novel approaches for CO₂ capture“. Thesis, University of Leeds, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.713474.
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This thesis is mainly concerned with the study of solvents of relevance for carbon capture and storage (CCS). The current industrial approach relies on amines to capture CO2, however this thesis describes a range of alternative non-amine based solvents, particularly phenols, saturated and unsaturated aliphatic acids, long chain fatty acids, aromatic acids, and β-dicarbonyl compounds (mainly ketones and esters). The CO2 capture capacities of these substrates have been compared with the industrial model substrate (monoethanolamine, MEA). From this study, phenols show 49-90% CO2 capture capacity whereas aromatic phenolic acids such as gallic acid show up to 100% theoretical CO2 capture capacity. Acetylacetone, a β-diketone shows 88% and the rest of the substrates from this and other groups show 50-60% CO2 capture capacity. However, some of the substrates, particularly simple mono and polycarboxylic acids showed negligible CO2 capture capacity, which can be understood on the basis of pKa. Particular attention has been paid to understanding the formation of bicarbonate salts, which would be expected under aqueous conditions. Clear evidence for their formation is provided by 13C NMR studies. The measured CO2 capture capacities of the new substrates have been correlated with pKa values. Those with pKa values between 9-13 have excellent to good CO2 capture capacity whereas others having pKa < 7, have insignificant CO2 capture capacity. The substrates with low pKa capture less volume of CO2 compared to those having high pKa, but release it more easily on heating. The second body of work is a study on the chemistry of MEA and its oxidised derivatives. MEA is currently the industry standard for CO2 capture. Given that power station flue gases contain large amounts of oxygen, and trace metals which may act as oxidation catalysts, understanding the chemistry of oxidised MEA derivatives is of increasing importance. This can have a significant effect on solvent activity and lifetime, which are important aspects of the economic profile of CCS. MEA was oxidised under a variety of conditions, and a complex mixture of products was formed. Many of these have been unambiguously identified by comparison with commercial or synthetic samples. The main oxidation products were then heated at 100°C for prolonged periods of time to mimic conditions in a commercial CCS system. Thermal degradation of MEA oxidation products was clearly observed, and in some cases, could be rationalised on the basis of established organic reactivity.
2
Ding, Tao. „Gas hydrates to capture and sequester CO₂“. Master's thesis, Mississippi State : Mississippi State University, 2004. http://library.msstate.edu/etd/show.asp?etd=etd-11102004-141404.
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3
Suri, Rajat. „CO₂ compression for capture-enabled power systems“. Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/46616.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2009.Includes bibliographical references (leaves 182-185).
The objective of this thesis is to evaluate a new carbon dioxide compression technology - shock compression - applied specifically to capture-enabled power plants. Global warming has increased public interest in carbon capture and sequestration technologies (CCS), but these technologies add significant capital and operating cost at present, which creates a significant barrier to adoption. Carbon dioxide compression technology makes up a high proportion of the additional cost required, making it a focal point for engineering efforts to improve the economic feasibility of carbon capture. To this effect, shock compressors have the potential to reduce both operating and capital costs with supporting compression ratios of up to 10:1, requiring less stages and theoretically allowing for the possibility of heat integration with the rest of the plant, allowing waste heat to be recovered from hot interstage compressed carbon dioxide. This thesis first presents a technical context for carbon dioxide compression by providing an overview of capture technologies to build an understanding of the different options being investigated for efficient removal of carbon dioxide from power plant emissions. It then examines conventional compression technologies, and how they have each evolved over time. Sample engineering calculations are performed to model gas streams processed by these conventional compressors. An analysis of shock compression is carried out by first building a background in compressible flow theory, and then using this as a foundation for understanding shock wave theory, especially oblique shocks. The shock compressor design is carefully analyzed using patent information, and a simulation of the physics of the shock compressor is created using equations from the theory section described earlier.
(cont.) A heat integration analysis is carried out to compare how conventional compressor technologies compare against the new shock compressor in terms of cooling duty and power recovery when integrated with the carbon dioxide capture unit. Both precombustion IGCC using Selexol and post-combustion MEA configurations are considered and compared. Finally an economic analysis is conducted to determine whether shock compression technology should be attractive to investors and plant managers deciding to support it. Key factors such as market, macroeconomic and technical risk are analyzed for investors, whereas a comparison of capital and operating cost is carried out for plant managers. Relevant risks associated with new compression technologies are also analyzed. It is found that there is no significant operating cost benefit to the shock compressor over the conventional compressor, both costing $3,700/hr for an IGCC plant. Power recovery is simply too low to justify the high power requirements in operating a shock compressor with a 10:1 ratio. The technical claims of the shock compressor (such as projected discharge temperature and pressures) seem reasonable after basic modeling, which shows a higher temperature and pressure than claimed by Ramgen.
by Rajat Suri.
S.M.
4
Lively, Ryan P. „Hollow fiber sorbents for post-combustion CO₂ capture“. Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43758.
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As concerns mount about the rise in atmospheric CO₂ concentrations, many different routes to reduce CO₂ emissions have been proposed. Of these, post-combustion CO₂ capture from coal-fired power stations is often the most controversial, as the CO₂ capture system will remove generating capacity from the grid whereas many of the other solutions involve increasing the generating capacity of the grid with low CO₂-emission plants. Despite this, coal-fired power stations represent a major point source for CO₂ emissions, and if a consensus is reached on the need to reduce CO₂ emissions, a low-cost method for capturing and storing the CO₂ released by these power plants needs to be developed. The overarching goal of this research is to design and develop a novel hollow fiber sorbent system for post-combustion CO₂ capture.
To achieve this goal, three objectives were developed to guide this research: i) develop a conceptual framework for hollow fiber sorbents that focuses on the energetic requirements of the system, ii) demonstrate that hollow fiber sorbents can be created, and a defect-free lumen layer can be made, iii) perform proof-of-concept CO₂ sorption experiments to confirm the validity of this approach to CO₂ capture. Each of these objectives is addressed in the body of this dissertation.
Work on the first objective showed that fiber sorbents can combine the energetic advantages of a physi-/chemi-sorption process utilizing a solid sorbent while mitigating the process deficiencies associated with using solid sorbents in a typical packed bed. All CO₂ capture technologies--including fiber sorbents--were shown to be highly parasitic to a host power plant in the absence of effective heat integration. Fiber sorbents have the unique advantage that heat integration is enabled most effectively by the hollow fiber morphology: the CO₂-sorbing fibers can behave as "adsorbing heat exchangers."
A dry-jet, wet-quench based hollow fiber spinning process was utilized to spin fibers that were 75wt% solid sorbent (zeolite 13X) and 25wt% support polymer (cellulose acetate). The spinning process was consistent and repeatable, allowing for production of large quantities of fibers. The fibers were successfully post-treated with an emulsion-based polymer (polyvinylidene chloride) to create a defect-free lumen side coating that was an excellent barrier to both water and gas permeation. A film study was conducted to elucidate the dominant factors in the formation of a defect-free film, and these factors were used for the creation of defect-free lumen layers. The work discussed in this thesis shows that the second objective of this work was definitively achieved.
For the third objective, sorption experiments conducted on the fiber sorbents indicated that the fiber sorbents CO₂ uptake is simply a weighted average of the support material CO₂ uptake and the solid sorbent uptake. Furthermore, kinetic experiments indicate that CO₂ access to the sorbents is not occluded noticeably by the polymer matrix. Using the fiber sorbents in a simulated rapid thermal swing adsorption cycle provided evidence for the fiber sorbents ability to capture the sorption enthalpy released by the CO₂-13X interaction. Finally, a slightly more-pure CO₂ product was able to be generated from the fiber sorbents via a thermal swing/inert purge process.
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Ogbuka, Chidi Premie. „Development of solid adsorbent materials for CO₂capture“. Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13276/.
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The application of solid adsorbents for gas separation in pre-combustion carbon capture from gasification processes has gained attention in recent times. This is due to the potential of the technology to reduce the overall energy penalty associated with the capture process. However, this requires the development of solid adsorbent materials with large selectivity, large adsorption capacity, fast adsorption kinetics for CO2 coupled with good mechanical strength and thermal stability. In this work, results on CO2 adsorption performance of three different types of adsorbents; a commercial activated carbon, phenolic resin activated carbons and zeolite templated carbons have been reported at atmospheric and high pressures conditions. The commercial activated carbon was obtained from Norit Carbons UK, the phenolic resin activated carbon was obtained from MAST Carbon Ltd., while the templated carbons were synthesized in the laboratory. A commercial activated carbon was used as bench mark for this study. Surface modification of these carbons was also undertaken and their CO2 uptake measurements at ambient and high pressure conditions were recorded. The commercial and templated carbons were modified by functionalising with amine group, while the phenolic resin carbon was modified by oxidation. The textural properties of the adsorbents was examined using the Micromeritics ASAP, while the CO2 adsorption capacities were conducted using the thermogravimetric analyser (TGA) and the High pressure volumetric analyser (HPVA). Textural properties of synthesized templated adsorbents were seen to depend on the textural characteristics of the parent material. The β-type zeolite produced the carbons with the best textural property. Increase in activation temperature and addition of furfuryl alcohol (FA) enhanced the surface area of most of the templated carbons. The textural property of all the adsorbents under study was seen to differently affect the CO2 uptake capacity at atmospheric (0.1 MPa) and high pressure conditions (up to 4 MPa). Micropore volume and surface area of the commercial activated carbons, phenolic resin activated carbons, and the templated carbons greatly influenced the adsorption trends recorded at ambient conditions. Total pore volumes positively influenced adsorption trend for templated carbons, but not the phenolic resin activated carbons at ambient and high pressure. This also positively influenced the adsorption trend for the commercial activated carbons, but at ambient conditions only. The surface area and the micropore volume have no effect on the adsorption trends for the templated carbons and the commercial activated carbons at high pressure conditions. However, these played a positive role in the adsorption capacities of the phenolic resin activated carbons at the same experimental conditions. Micropore volume and surface area of adsorbents play a major role on the adsorption trends recorded for the modified adsorbents at ambient conditions only. No trend was recorded for adsorption capacities at high pressure conditions. Only the oxidized phenolic resin activated carbon showed a positive adsorption trend with respect to total pore volume at high pressure condition. The amine modified commercial activated carbon showed no positive adsorption trend with respect to the total pore volume at both ambient and high pressure conditions, while the amine modified templated carbon showed no adsorption trend with respect to the textural properties at ambient and high pressure conditions. CO2 uptake measurements for the modified and unmodified templated carbon and phenolic resin carbon, were observed to be higher than those of the commercial activated carbon at ambient and high pressure conditions. Maximum CO2 uptake was recorded at 25 oC. At ambient pressure, the phenolic resin carbon (MC11) showed the highest CO2 uptake of approximately 3.3 mmol g-1, followed by the commercial activated carbon (2.4 mmol g-1), then, the templated carbon (2.4 mmol g-1). At high pressure, the templated carbons (β-AC7-2%) showed the highest CO2 uptake (21.3 mmol g-1), followed by phenolic resin carbon (MC4 - 12.2 mmol g-1), and the commercial activated carbon (6.6 mmol g-1). When samples were modified, the amine modified templated carbon and oxidized phenolic resin carbon showed the highest CO2 uptake of 2.9 mmol g-1 each at ambient pressure, followed by the commercial activated carbon (2.7 mmol g-1). At high pressure conditions, the oxidized phenolic resin carbon showed the highest (10.6 mmol g-1) uptake level, followed by the templated carbon (8.7 mmol g-1), and commercial activated carbon (6.5 mmol g-1).
6
Bollini, Praveen P. „Amine-oxide adsorbents for post-combustion CO₂ capture“. Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52908.
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Amine functionalized silicas are promising chemisorbent materials for post-combustion CO₂ capture due to the high density of active sites per unit mass of adsorbent that can be obtained by tuning the synthesis protocol, thus resulting in high equilibrium CO₂ adsorption capacities. However, when compared to physisorbents, they have a few disadvantages. Firstly, oxidative degradation of the amine groups reduces the lifetime of these adsorbent materials. Furthermore, rapid heat release following the reaction between amines and CO₂ results in large local temperature spikes which may adversely affect adsorption equilibria and kinetics. Thirdly, there is a lack of fundamental understanding of CO₂-amine adsorption thermodynamics, which is key to scaling up these materials to an industrial-scale adsorption process. In this dissertation the qualitative and quantitative understanding of these three critical aspects of aminosilica adsorbents have been furthered so these materials can be better evaluated and further tuned as adsorbents for post-combustion CO₂ capture applications.
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Didas, Stephanie Ann. „Structural properties of aminosilica materials for CO₂ capture“. Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54020.
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Increased levels of carbon dioxide in the atmosphere are now widely attributed as a leading cause for global climate change. As such, research efforts into the capture and sequestration of CO2 from large point sources (flue gas capture) as well as the ambient atmosphere (air capture) are gaining increased popularity and importance. Supported amine materials have emerged as a promising class of materials for these applications. However, more fundamental research is needed before these materials can be used in a practically relevant process. The following areas are considered critical research needs for these materials: (i) process design, (ii) material stability, (iii) kinetics of adsorption and desorption, (iv) improved sorbent adsorption efficiency and (v) understanding the effects of water on sorbent adsorption behavior. The aim of the studies presented in this thesis is to further the scientific community’s understanding of supported amine adsorbents with respect to stability, adsorption efficiency and adsorption behavior with water.
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Li, Jia. „Options for introducing CO₂ capture and capture readiness for coal fired power plants in China“. Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/6393.
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China has been building at least 50GW of new coal‐fired power plants every year since 2004. Previous carbon capture and storage (CCS) research has mainly focussed on technology improvements or stakeholder opinion surveys, without picturing the overall concerns and barriers for deploying such technology in China. This thesis therefore explores the engineering and policy requirements to implement CCS and CO2 Capture Ready (CCR) in Chinese coal‐fired power plants, key enablers for future deployment. A preliminary study of the Chinese gasification industry shows there are early opportunities to capture carbon dioxide from gasification plants. However, as power from conventional pulverised coal (PC) accounts for the majority of electricity generated in China, the most promising emission reduction method for China could be through implementation of CCS technology in large PC plants. An investigation of the current PC plant layouts and operating parameters has been carried out during the course of the study. The results show that, in the absence of CCR designs, a large fraction of such new coal power plants built within the next decade could face ‘carbon lock-in’. A site specific system model using ASPEN Plus to demonstrate the possible changes that could be applied to an existing power plant and a retrofit plant is included in the study. A capture ready power plant site selection method has also been developed, to identify possible sites and to aid understanding of the criteria that should be considered when planning a capture ready plant. A case study of a capture ready power plant in Guangdong province, China shows the benefit of regional planning. Finally, the result of the first stakeholder perception survey on making new coal‐fired plants CCR, conducted in early 2010, are presented and analysed. Evidence for a supportive attitude towards CCR could indicate that this may be a route to early commercial demonstration of CCS in China.
9
Di, Felice Luca, Claire Courson, Katia Gallucci, Nader Jand, Sergio Rapagnà, Pier Ugo Foscolo und Alain Kiennemann. „One-step hydrocarbons steam reforming and CO 2 capture“. Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-192989.
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10
Di, Felice Luca, Claire Courson, Katia Gallucci, Nader Jand, Sergio Rapagnà, Pier Ugo Foscolo und Alain Kiennemann. „One-step hydrocarbons steam reforming and CO 2 capture“. Diffusion fundamentals 7 (2007) 3, S. 1-2, 2007. https://ul.qucosa.de/id/qucosa%3A14159.
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11
Blamey, John. „Improved performance of CaO-based sorbent for CO₂ capture“. Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9650.
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Calcium looping is a CO2 capture technology that is currently being developed on a 1 MWth pilot-scale. It has advantages including the ability to reclaim high-grade heat, the use of a relatively inexpensive, abundant and benign sorbent, and the potential to de-carbonise both power generation and cement manufacture. It makes use of the reversible carbonation of CaO to remove CO2 from a flue gas and provide pure CO2 for compression and storage, in a cyclical process. One aspect that is disadvantageous is the deactivation of CaO-sorbent upon cycling through reactive sintering; it is enhancement of sorbent that is examined here. Periodically hydrating sorbent, which can enhance sorbent performance by increasing reactive porosity, has been investigated: • Hydration conversion decreases following cycles of carbonation and calcination and at higher hydration temperatures. The latter has important consequences for the ability to reclaim high-grade heat from and reduce thermal cycling during the hydration process; • Particle breakage can occur upon hydration, which could be problematic for fluidised processes. This is more significant at lower hydration temperatures and for more highly sintered sorbents; • Direct carbonation of hydrated sorbent, rather than following a dehydration step, results in increased mechanical stability and increased reactivity to CO2; • Carbonation extent has an approximately linear relationship with prior hydration extent for equivalent carbonation methods; • A shrinking core model has been developed to describe the rate of reaction upon hydration. This successfully describes most data, but deviations are observed under conditions where pore blockage is likely. Enhancement of the performance of natural sorbent through surface doping with potassium compounds has also been investigated. KCl was found to enhance longterm conversion in the fluidised bed, with two mechanisms proposed: • Reduced friability of limestone, through KCl melt formation; • Increased carbonation rates in the slow solid-state diffusion phase.
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Huang, Quanzhen. „THERMAL DEGRADATION OF AMINES FOR CO2 CAPTURE“. UKnowledge, 2015. http://uknowledge.uky.edu/chemistry_etds/51.
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In the selection of candidates for CO2 absorption, solvent thermal degradation has become a general concern due to the significant impact on operational cost and the intention to use thermal compression from high temperature stripping to minimize the overall process energy. In this research, the impact of flue gas contaminants on Monoethanolamine (MEA) thermal degradation was investigated at elevated temperatures consistent with those in the CO2 stripper. Nitrite, fly ash, sulfate and thiosulfate were each added to 5.0 M MEA and the contaminant-containing MEA solutions were degraded at 125 °C, 135 °C and 145 °C. MEA degrades significantly more in the presence of nitrite (5000 ppm) than MEA alone at the same amine molar concentration for all three temperatures. MEA degradation activation energy of MEA-nitrite solution is approximately one-seventh of that of MEA solution without nitrite. Fly ash was observed to inhibit nitrite-induced MEA degradation and greatly increase the MEA degradation activation energy of MEA-nitrite solution. Fly ash, sodium sulfate and sodium thiosulfate by themselves were not shown to impact MEA thermal degradation rate.
Sodium salts of glycine, sarcosine, alanine and ß-alanine were thermally degraded at 125 °C, 135 °C and 145 °C, respectively, to discover the structural reasons for their thermal stability. These four amino acids have enhanced thermal degradation rates compared to MEA. The stability order for amino acid salts tested to date is: sarcosinate > alaninate > ß-alaninate. Calculated activation energies for the degradation processes are lower than that of MEA. ß-Alaninate (ß-Ala) thermal degradation generates ß-Ala dimer (major degradation product), ß-Ala dimer carbamate and tetrahydro-1,3-oxazin-6-one.
Functional groups, amine orders and steric effect were investigated for their impact on amine thermal degradation. Primary amines with chain structures showed a thermal stability trend as diamine > alkanolamine > amino acid salt. For alknolamine and diamine structural isomers, the primary amines are more stable than the secondary amines. Steric hindrance around the amine group plays a global positive role in protecting amines against thermal degradation.
13
Pandian, Babu Vinod Babu. „High-solids, mixed-matrix hollow fiber sorbents for CO₂ capture“. Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53435.
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Post-combustion carbon capture, wherein the CO2 produced as a result of coal combustion is trapped at the power plant exhaust, is seen as a bridging technology to reduce CO2 emissions and combat climate change. This capture process will however impose a parasitic load on the power plant and technologies need to be developed to minimize this energy penalty. This research focuses on a technology which uses solid sorbents fashioned into a hollow fiber form that allows water-moderated thermal cycling as a means of trapping CO2 from flue gas. While hollow fiber technology has intrinsic advantages over competing liquid amine and packed bed technologies, the materials used to fabricate hollow fibers and the fabrication process itself need to be optimized in order to result in competitive, robust hollow fiber sorbents. This dissertation focuses on the material selection process for each component of the hollow fiber platform and discusses ways to optimize the fiber and barrier layer formation. Different materials were evaluated to function as the solid sorbent, the matrix polymer and the barrier layer; and eventually their performance was measured against past work in this area.
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Sultan, Dewan Saquib Ishanur. „The capture of CO₂ from process streams using solid sorbents“. Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708420.
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Obhielo, Esgeboria. „Synthesis, characterisation and optimisation of novel adsorbents for CO₂ capture“. Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24838.
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In this study, a suite of novel CO₂ capture sorbents were prepared employing three facile synthetic routes: amine assimilation (co-synthesis), wet impregnation and in situ-impregnation synthesis, to develop a range of materials capable of efficiently adsorbing CO₂ while demonstrating their applicability as alternative materials for CO₂ capture from coal and gas fired power plants via post-combustion carbon capture. Prepared sorbents were characterised for individual physical and chemical properties, using, scanning electron microscopy, infrared spectroscopy, thermogravimetric analysis, elemental analyses and N₂ sorption at 77 K. CO₂capture capacities were determined using gravimetric analysis under a range of analysis conditions (different temperature and pressure), with the corresponding effects of materials characteristics on CO₂ capacities investigated. The effect of amine incorporation was explored in detail, with findings first bench-marked against the corresponding amine free counterparts, and, then, the effect of increasing amine content analysed. So far, within the context of this study, results suggest that materials prepared via the synthetic routes adopted, exhibit high degrees of synthetic control; in addition, CO₂ capture capacities were determined to be dependent upon both textural properties but, more importantly, the basic nitrogen functionalities contained within these materials. This observation was prominent with amine in-situ impregnated silica and melamine resorcinol formaldehyde samples, but not wholly for bio-inspired amine silica samples, as the degree of amine functionalisation could not be controlled by the synthetic route chosen. Irrespective, all materials have shown enhanced adsorption performance as a result of the incorporation of basic nitrogen functionalities into the sorbent structures. Furthermore, prepared materials exhibited easy regeneration and maintained stable sorption capacities ≤ 99.9% over the cycles analysed, with results obtained suggesting new strategies for carbon capture materials development for efficient CO₂ capture from power plant flue gas and other relevant applications.
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Khurram, Aliza. „Combined CO₂ capture and electrochemical conversion in non-aqueous environments“. Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127053.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 234-253).
Carbon capture, utilization, and storage (CCUS) technologies have a central role to play in mitigating rising CO₂ emissions and enabling sustainable power generation. Most industrially mature CCS technologies based on amine chemisorption are highly energy-intensive, consuming up to 30% of the power generating capacity of the plant in order to thermally regenerate the sorbents for continued capture. Moreover, the released CO₂ must additionally be compressed and stored permanently, which adds additional energy penalties and potential risks of release. To address these challenges, this thesis develops a new strategy for integrating CO₂ capture and conversion into a single process stream.
Such an approach, which employs CO₂ in the captured state as the reactant for subsequent electrochemical reactions, eliminates the need for energetically-intensive sorbent regeneration and CO₂ release between capture and utilization steps while potentially providing new solutions for the storage challenge. In the first part of this thesis, a proof-of-concept demonstration of combined CO₂ capture and conversion within a Li-based electrochemical cell is presented. To develop this system, new electrolyte systems were first designed to integrate amines (used in industrial CO₂ capture) into nonaqueous electrolytes. The resulting systems were found to be highly effective in both capturing and activating CO₂ for subsequent electrochemical transformations upon discharge of the cell.
This activity was particularly well-demonstrated in solvents such as DMSO where CO₂ normally is completely inactive, in which the amine-modified electrolytes containing chemisorbed CO₂ were found to enable discharge at high cell voltages (~2.9 V vs. Li/Li⁺) and to high capacities (> 1000 mAh/gc), converting CO₂ to solid lithium carbonate. Formation of a densely-packed, solid phase product from CO₂ is not only logistically attractive because it requires less storage space, but also eliminates the costs and safety risks associated with long-term geological storage of compressed CO₂. In addition, the conversion process generates electricity at point-of-capture, which may help to incentivize integration of the technology with existing point-source emitters. While promising, this initial system exhibited several challenges including slow formation of the active species in solution.
To address this, a suite of experimental and computational methods were employed to elucidate the influence of the electrolyte on electrochemical reaction rates. Reduction kinetics were found to be influenced by alkali cation desolvation energetics, which favors larger alkali cations such as potassium. Through further development, amine-facilitated CO₂ conversion was also demonstrated to be transferrable to other amine- and solvent- systems, opening a potentially large design space for developing improved electrolytes. Furthermore, the effect of operating temperature was investigated to evaluate the potential of this technology to integrate with practical CO₂ capture needs. While higher temperatures (40°C
by Aliza Khurram.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Mechanical Engineering
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Lucquiaud, Mathieu. „Steam cycle options for capture-ready power plants, retrofits and flexible operation with post-combustion CO₂ capture“. Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/5942.
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The energy penalty for post‐combustion carbon dioxide capture from fossil‐fired power plants can be greatly reduced ‐ independently of the intrinsic heat of regeneration of the solvent used ‐ by effective thermodynamic integration with the power cycle. Yet expected changes in electricity generation mix and the current immaturity of post‐combustion capture technology are likely to make effective thermodynamic integration throughout the operating life of such plants a challenging objective to achieve because of a requirement for extensive part‐load operation and also for matching to future technology improvements. Most previous published studies have, however, focused on base‐load operation of the power cycle and the carbon dioxide capture plant and with the assumption of a fixed technology. For carbon dioxide capture‐ready plants the characteristics of the capture plant are also not known when the plant is designed. The plant must operate initially without capture at a similar efficiency to ‘standard’ plants to be competitive. Capture‐ready plants then also need to be able to be retrofitted with unknown improved solvents and to be capable of integration with a range of future solvents. This study shows that future upgradability for post‐combustion capture systems can be facilitated by appropriate steam turbine and steam cycle designs. In addition fossil‐fired power plants with postcombustion capture may need to be able to operate throughout their load range with the capture unit by‐passed, or with intermediate solvent storage to avoid the additional emissions occurring when the absorption column is by‐passed. Steam cycles with flexible steam turbines can be adequately designed to accommodate for part‐load operation with these novel operating conditions and with rapid ramp rates. Several approaches for effective capture‐ready pulverised coal and natural gas plants are also described. These achieve identical performance before retrofit to a conventional plant with the same steam conditions, but have the potential to perform well after capture retrofit with a wide range of solvents, at the expense of only a small efficiency penalty compared to hypothetical plants built with perfect foreknowledge of the solvent energy requirements. For existing plants that were not made capture‐ready, and provided sufficient space is available and other physical limits are not too constraining, ways to achieve effective thermodynamic integration are also discussed.
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Li, Hailong. „Thermodynamic properties of CO₂ mixtures and their applications in advanced power cycles with CO₂ capture processes /“. Stockholm : Department of chemical engineering and technology, Royal institute of technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9109.
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Li, Fuyue. „Amine-functionalized polymeric hollow fiber sorbents for post-combustion CO₂ capture“. Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53119.
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Polymeric hollow fiber sorbents were functionalized with amine moieties for improving the carbon dioxide sorption capacity from flue gas to reduce the greenhouse gas emissions from coal-fired power plants. Three different experimental pathways were studied to form the amine-functionalized hollow fiber sorbents. Aminosilane functionalized cellulose acetate (CA) fibers, polyethyleneimine (PEI) functionalized polyamide-imide (PAI, Torlon® fibers and PEI post-infused and functionalized Torlon®-silica fibers were formed. CO₂ equilibrium sorption capacity data were collected by using the pressure decay sorption cell and thermal gravimetric analyzer. Other physio-chemical properties of the amine-functionalized fiber sorbents were characterized by using fourier-transform infrared spectroscopy, elemental analysis, and scanning electronic microscopy. Different reaction conditions were studied on the effect of sorption isotherms. Aminosilane-CA fibers were the first proof-of-concept for forming the amine functionalized polymer hollow fibers. PEI-PAI fibers were designed as a new method to reach enhanced sorption capacities than Aminosilane-functionalized CA fibers. PEI post-infused and functionalized Torlon®-silica fibers have further enhanced sorption capacity; however they easily degrade with similar reaction for forming PEI-PAI fibers. Lumen-side barrier layers were created successfully via post-treatment technique of using the crosslinked Neoprene® polymer onto PEI-functionalized PAI fibers. PEI-functionalized PAI fibers also have good cyclic stability and low heat of sorption.
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Archbold, Brad. „Using algae to capture CO₂ and as a feedstock for biofuel“. Online pdf file accessible through the World Wide Web, 2007. http://archives.evergreen.edu/masterstheses/Accession86-10MES/Archbold_%20B%20MESThesis%202007.pdf.
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Masnadi-Shirazi, Mohammad Sadegh. „Biomass/fossil fuel co-gasification with and without integrated CO2 capture“. Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46917.
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Biomass/fossil fuel co-gasification could be a bridge between energy production based on fossil fuels and energy production based on renewable fuels. In this work, CO₂ co-gasification of switchgrass with coal and fluid coke was conducted in a thermogravimetric analyzer at 800°C. Coal gasification kinetics were inhibited or enhanced, depending on the switchgrass concentration in the mixture: for low K/Al and K/Si molar ratios in the mixture, it seemed that the coal ash sequestrated the biomass potassium needed for Kalsilite (KAlSiO4) formation, and thus, no catalytic effect was observed until the biomass to coal mass ratio reached 3:1, where the switchgrass ash supplied enough potassium to more than satisfy the minerals in the coal ash. For high K/Al and K/Si molar ratios in the mixture, the non-reacted residual potassium acted as catalyst and enhanced the coal gasification. The fluid coke contained much lower Al and Si relative to the coal. Hence, the CO₂ gasification kinetics of fluid coke were significantly augmented by blending it with switchgrass, due to the rich presence of potassium in the biomass.
A low-ash coal and switchgrass rich in potassium were selected to steam gasify it as a single-fuel and in 50:50 wt% coal:switchgrass mixtures in a pilot scale fluidized bed with silica sand as the bed material at ~ 800 and 860°C and 1 atm. With biomass added to the coal, the hydrogen and cold gas efficiencies, gas yield and HHV of the product gas were enhanced relative to single-fuel gasification. The product gas tar yield was also reduced considerably due to decomposition of tar catalyzed by switchgrass alkali and alkaline earth metals.
In the quest for a more sustainable process, coal/switchgrass steam co-gasification was integrated with in-site CO2 capture with limestone. Five gasification/carbonation and calcination cycles were performed in a pilot scale fluidized bed. Hydrogen production was enhanced due to partial adsorption of CO₂ by the CaO sorbent particles (bed material). The sorbent particles decayed and lost their utilization efficiency in the course of cycling due to sintering.
A simple equilibrium model and an empirically kinetically-modified equilibrium model were also presented to predict syngas composition.
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Binti, Ishak Nisrin Alyani. „Enacting organisational and consumer value capture : a social co-creation perspective“. Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/17138.
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The capability of the organisation in capturing customer value of experience (VoE) has led to continuous social interaction and spawned innovative ways to collaborate and co-create with the customers. This notion of reciprocal engagement is referred to as social co-creation. The co-creation paradigm represents value and is referred to as a function of experience other than the product itself. However, there is a critically needs for the organisation to formulate a 'value capture strategy' through the lens of social co-creation. It is evident that the fundamental question of the causal relationship between social media and co-creation has not been fully explained. The research developed a value capture framework in order to have a clear need to understand the various perceptions of four important conditions, social co-creation, customer engagement, engagement platform and organisation capability on value capture. The theoretical aspect of 'Absorptive Capacity Theory (ACT)' is used to demonstrate the organisational capability in order to recognise, identify, assimilate and implement the VoE in the organisation as part of competitive advantage along with existing of social technologies. In this respect, an original conceptual framework was formulated based on evidence within the current literature where a series of constructs are reported to guide the empirical fieldwork in identifying a 'value capture strategy'. The research adopted a qualitative methodology for the data collection approach which consequently enabled an exploratory and interpretive investigation. This included three pilot studies, twentyeight semi-structured interviews and one validation phase with experienced senior managers involved in co-creation within the technology and services industry who were regarded as valid respondents. The findings addressed external and internal conditions of value capture framework for VoE as a result of the analysis. The external condition focuses on organisation capability in recognising a customer active participation with the engagement platform. The internal condition enables an organisational strategy to assimilate and implement the VoE through co-creation initiatives in capturing the VoE. The research considers the organisation role as an actioner purposes on using a social co-creation for direct communication as part of the organisations practice. 9 The study not only contributes to the knowledge of social co-creation generally, but also extending the needs for the organisation on considering the internal condition for the organisation to identifies the VoE from customer participation. With that regards, the social co-creation engagement works as the interface before extending on cocreation stages which more direct, in-depth conversations with customers internally. The evidence is presented which confirms that a value capture strategy in cocreation is important for organisations stability and enhanced service delivery. By formulating a value capture framework, it creates a much deeper understanding of how each element were related and correlated to reach potential end result for the organisation. The implications of the study are that organisations should carefully consider the role of social media on engaging with the customers and propose to develop an online engagement network with their customers in order to have more direct and effective communication tools. This would allow them to have the right strategy on selecting the right customer to engage, for the right purposes at the right time is far more important from creating a massive communication.
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Fisher, James C. II. „The Reduction of CO2 Emissions Via CO2 Capture and Solid Oxide Fuel Cells“. University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1247250147.
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Ghasemian, Langeroudi Elahe. „Quantitative aspects of CO₂-grafted amine interactions in gas-liquid-solid solubility equilibrium : applications to CO₂ capture“. Master's thesis, Université Laval, 2010. http://hdl.handle.net/20.500.11794/21467.
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Les effets liés à la présence d'eau liquide sur la capacité d'adsorption de CO₂ par une silice mésoporeuse de type SBA-15 fonctionnalisée au moyen des amines suivantes: aminopropyltrimethoxysilane (APS) et N-(2-aminoéthyl) -3 - (aminopropyl) trimethoxysilane (AEAPS) ont été examinés pour évaluer le potentiel de ce mode de contact dans des laveurs gaz-liquide-solide. Les résultats ont été comparés à la capacité d'adsorption de CO₂ des amines greffées dans des conditions humides et sèches ainsi qu'à la capacité d'absorption de CO₂ dans les systèmes gaz-liquide avec des solutions aqueuses d'aminés ayant des structures semblables à celles des amines greffées. Dans ces conditions, une estimation de l'adsorption physique de CO₂ a été obtenue par l'étude de la SB A-15 non-modifiée. En outre, afin d'évaluer l'efficacité et la stabilité à long terme de l'association amine/SBA-15, les amines greffées ont été soumises à huit cycles successifs d'immersion dans les milieux aqueux d'une durée de 24 h chacune. Les échantillons récupérés ont été caractérisés au moyen de la diffraction aux rayons, des isothermes de sorption d'azote et d'analyse élémentaire CHN. Jusqu'à 40% de la quantité d'aminés greffées a subi une lixiviation durant les quelques premiers cycles de régénération; par la suite, la teneur en azote de l'AEAPS est demeurée relativement stable, contrairement à l'APS qui a connu une moindre stabilité. Fait intéressant, les structures des deux matériaux greffés, APS et AEAPS, sont demeurées intactes après plusieurs expositions à l'eau. L'efficacité de capture de CO₂ la plus élevée a été obtenue dans le cas des amines aqueuses (voie homogène). Cependant, la capture de CO₂ à l'aide d'aminés greffées dans le cas du système triphasique (gaz-liquide-solide) a donné lieu, pour des conditions opératoires comparables, à des valeurs intermédiaires entre les voies sèche et humide du mode de contact gaz-solide.
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Wishrojwar, Anitha Suhas. „SYNTHESIS, CHARACTERIZATION AND DEVELOPMENT OF CATALYSTS FOR CO2 CAPTURE“. UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_theses/42.
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Fossil fuel and advanced industrialization techniques contribute to global warming through emissions of greenhouse gases such as CO2. In order to mitigate climate change, there is a desperate need to reduce CO2 emissions from different sources. CO2 capture and sequestration (CCS) play an important role in these reductions.
Naturally occurring enzymes, e.g., carbonic anhydrase (CA), can catalyze these reactions in living systems. Much effort has been focused on complexes of zinc with ligands such as teta, cyclen and tripodal ligands including BIMA and Trispyrazolylborates. These complexes have many interesting CO2 capture properties, but maintain toxic perchlorate ions.
We desired to replace them with less hazardous counteranions like BF4- or PF6-. Our research focused mainly on the synthesis and characterization of Zn, Co and Cu cyclen and teta complexes that could mimic CA. We also examined some of these species for catalytic CO2 hydration behavior on wetted-wall column (WWC) at Center for Applied Energy Research (CAER).
We successfully synthesized and characterized eight new complexes. These catalysts as CO2 capture systems are more stable have low molecular weights (compared to CA) and more cost effective than enzymes. In terms of catalytic activity significant results were obtained only for few of the catalysts
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Gallucci, Katia, Ferdinando Paolini, Felice Luca Di, Claire Courson, Pier Ugo Foscolo und Alain Kiennemann. „SEM analysis application to study CO 2 capture by means of dolomite“. Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-193012.
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Gallucci, Katia, Ferdinando Paolini, Felice Luca Di, Claire Courson, Pier Ugo Foscolo und Alain Kiennemann. „SEM analysis application to study CO 2 capture by means of dolomite“. Diffusion fundamentals 7 (2007) 5, S. 1-11, 2007. https://ul.qucosa.de/id/qucosa%3A14163.
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Fei, Yang. „Computational fluid dynamics and process co-simulation applied to carbon capture technologies“. Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/11521/.
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In the energy supply sector, coal will still remain as a dominate role in the foreseeable future because: it is comparatively cheap and widely distributed around the world and more importantly, carbon capture and storage (CCS) technologies make it possible to depend on coal with almost zero emission of carbon dioxide (CO2). CCS involves capturing and purifying CO2 from the emission source and then sequestering it safely and securely to avoid emission to the atmosphere. Both the post-combustion and the oxy-fuel technologies can be applied to existing power plants for CCS retrofit. Accurate prediction of the performance of a CCS plant plays an important role in reducing the technical risk of future integration of CCS with existing power plants. This research combines the fundamental computational fluid dynamics (CFD) and system process simulation technologies so that an efficient co-simulation strategy can be achieved. A 250 kWth coal combustion facility combined with a CO2 post capture plant is taken to test the conception of the CFD and process co-simulation approach. The CFD models are employed to account for the combustion facility and the predicted results on the outlet gas compositions, temperatures and mass flow rates are used to generate reduced order models to linked to the model for the PACT CO2 post capture plant so that a pilot scale whole plant model is achieved and validations have been made where it is possible. Afterwards, the a large scale conventional air-coal firing power plant is taken into investigation: the CFD models for the boiler and the process models for the whole plant have been developed. Further, the potential of retrofitting this power plant to oxy-firing is evaluated using a CFD and process co-simulation approach. The CFD techniques are employed to simulate the coal combustion and heat transfer to the furnace water walls and heat exchangers under air-firing and oxy-firing conditions. A set of reduced order models has been developed to link the CFD predictions to the whole plant process model in order to simulate the performance of the power plant under different load and oxygen enrichment conditions in an efficient manner. Simulation results of this 500 MWe power plant indicate that it is possible to retrofit it to oxy-firing without affecting its overall performance. Further, the feasible range of oxygen enrichment for different power loads is identified to be between 25% and 27%. However, the peak temperature on the superheater platen 2 may increase in the oxy-coal mode at a high power load beyond 450 MWe.
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Chowdhury, Mohammad. „Effects of brown coal fly ash on 30% monoethanolamine CO₂ capture systems“. Thesis, Federation University Australia, 2019. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/171010.
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Accumulation of fly ash during post-combustion capture (PCC) of CO2 is an emerging concern. This work assesses concerns that soluble ash components (e.g. Na, Ca, Mg) increase conductivity of amine systems increasing corrosion rates, and decreasing CO2 capture e ciency; slightly soluble metals ions (e.g. Fe) may catalyse amine oxidation; and insoluble ash components cause erosion and blockages in the PCC plants as well as providing catalytic surfaces. Loy Yang brown-coal y ashes (using XRD, SEM, EDS and ICP-MS) are rst characterised and separated into soluble, insoluble and char fractions. The e ect of each fraction on MEA oxidation (measured by UV-vis and organic acid formation) and corrosion is determined using lab-scale experiments in static and stirred pressurised reactors at simulated PCC stripper conditions. Fly ash was three times more soluble in severely oxidising conditions compared to mild 30% MEA extractions. Vantho te represents 10-20% of the y ash and was the main source of sodium, calcium and magnesium ions while Szmolnockite was a source of iron. Iron solubility was dependent on conditions, with 5% soluble in aqueous MEA and 10% in simulated desorber conditions. The soluble fraction was the only ash fraction to signi cantly promote MEA oxidation. Aged pall rings from a PCC pilot plant had severe grain boundary corrosion and chromiumoxide depletion. Grain boundary corrosion was less severe in pall rings under severely oxidising conditions. The e ects of soluble ash were unclear while organic acids promoted pitting. Fly ash is an important source of soluble sodium, calcium and iron into 30% MEA. The insoluble fraction had minimal impact on MEA oxidation and corrosion, suggesting that it was inert. Soluble ash fractions increased corrosion severity and promoted MEA oxidation. This work shows that deep y ash removal prior to PCC is particularly important for ashes with high solubility in the CO2 absorption system.Doctor of Philosophy
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Hassan, S. M. Nazmul. „Techno-Economic Study of CO2 Capture Process for Cement Plants“. Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/925.
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Carbon dioxide is considered to be the major source of GHG responsible for global warming; man-made CO2 contributes approximately 63. 5% to all greenhouse gases. The cement industry is responsible for approximately 5% of global anthropogenic carbon dioxide emissions emitting nearly 900 kg of CO2 for every 1000 kg of cement produced! Amine absorption processes in particular the monoethanolamine (MEA) based process, is considered to be a viable technology for capturing CO2 from low-pressure flue gas streams because of its fast reaction rate with CO2 and low cost of raw materials compared to other amines. However, MEA absorption process is associated with high capital and operating costs because a significant amount of energy is required for solvent regeneration and severe operating problems such as corrosion, solvent loss and solvent degradation.
This research was motivated by the need to design size and cost analysis of CO2 capture process from cement industry. MEA based absorption process was used as a potential technique to model CO2 capture from cement plants. In this research four cases were considered all to reach a CO2 purity of 98% i) the plant operates at the highest capacity ii) the plant operates at average load iii) the plant operates at minimum operating capacity and iv) switching to a lower carbon content fuel at average plant load. A comparison among four cases were performed to determine the best operating conditions for capturing CO2 from cement plants. A sensitivity analysis of the economics to the lean loading and percent recovery were carried out as well as the different absorber and striper tray combinations.
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Kahr, Juergen. „Investigation of metal-organic frameworks as adsorbents for CO₂ capture from flue gas“. Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/7045.
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The post-synthetic modification of CPO-27(Mg) by introducing nickel cations into the framework is described. A combination of surface sensitive XPS analysis, synchrotron powder X-ray diffraction and selected area and bulk EDX measurements revealed the distribution of Ni²⁺ throughout the crystal with the highest concentration towards the external surface forming a nickel-rich rim. By adding nickel acetate and chloride salts in combination with a weak acid, Ni²⁺ contents of up to 67% for the bulk material were achieved via a one-pot preparative procedure. A combined mechanism of overgrowth and isomorphous cation exchange is proposed. The study led to an improvement of porosity to N₂ (77 K) up to 17 mmol g⁻¹, close to values achieved elsewhere via complex activation procedures. High values for the adsorption of carbon dioxide of up to 6.7 mmol g⁻¹ at temperatures and partial pressure relevant for carbon capture from post-combustion power plants were accomplished (298 K, 0.1 bar) and were shown to be repeatable over cycles under dry conditions. The synthesis, structure and adsorption properties of a series of zinc imidazolate zeolitic imidazolate framework, ZIF, materials was also investigated. Structural details of the zinc nitroimidazolate ZIF-65(Zn) were determined by Rietveld refinement. Heating experiments of as prepared ZIF-65(Zn) revealed a partial transformation from a cubic framework to an unknown structure, shown to be reversible. The new phase possess high porosity to nitrogen and showed stepped, hysteretic adsorption and desorption isotherms for at 77 K and CO₂ at 298 K. Using methanol instead of DMF in synthesis yielded a novel dense non-porous zinc nitro imidazolate structure. A series of novel structures was prepared via synthesis including a mixture of 2- nitroimidazole (NIm) and purine with different zinc metal sources. Two MOF structures were found to consist of purine linkers only, but could not be rendered porous. By changing the metal source or solvent an isoreticular structure of the ZIF- 68 (GME) family was obtained, composed of purine and NIm, as well as a novel form of a mixed linker ZIF with the RHO topology with Im-3m symmetry that exhibits large pores and exo-Zn and exo-NIm moieties decorating the cavity walls. The nitrogen uptake (77 K) of 6.5 mmol g⁻¹could be increased to 12.5 mmol g⁻¹ by removing exo-moieties through water washing. The use of a diamino functionalised purine linker (DAP) together with NIm gave a new ZIF material, STA-17, with a novel topology. The structure was found to exhibit porosity to nitrogen (77 K) of 6.5 mmol g⁻¹ and carbon dioxide at (198 K) of 5 mmol g⁻¹, but shows weak interaction with CO₂ at 298 K. Indexing from synchrotron powder XRD data gave a hexagonal unit cell with a = b = 29.725 Å and c = 18.606 Å. Subsequent analysis of the composition using NMR, TGA and IR techniques revealed the presence of both linkers in the structure and a linker ratio of 2:1 (NIm : DAP). Although crystals of suitable quality for single crystal X-ray diffraction were not obtained, a partial model for the structure is proposed via analogy with a hypothetical zeolite structure and analysis of powder X-ray diffraction data.
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Hong, Jongsup. „Techno-economic analysis of pressurized oxy-fuel combustion power cycle for CO₂ capture“. Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/50567.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Includes bibliographical references (leaves 124-127).
Growing concerns over greenhouse gas emissions have driven extensive research into new power generation cycles that enable carbon dioxide capture and sequestration. In this regard, oxy-fuel combustion is a promising new technology for capturing carbon dioxide in power generation systems utilizing hydrocarbon fuels. Combustion of a fuel in an environment of oxygen and recycled combustion gases yields flue gases consisting predominantly of carbon dioxide and water. To capture carbon dioxide, water is condensed, and carbon dioxide is purified and compressed beyond its supercritical state. However, conventional atmospheric oxy-fuel combustion systems require substantial parasitic energy in the compression step within the air separation unit, a flue gas recirculation system and carbon dioxide purification and compression units. Moreover, a large amount of flue gas latent enthalpy, which has high water concentration, is wasted. Both lower the overall cycle efficiency. Alternatively, pressurized oxy-fuel combustion power cycles have been investigated. In this thesis, the analysis of an oxy-fuel combustion power cycle that utilizes a pressurized coal combustor is reported. We show that this approach is beneficial in terms of larger flue gas thermal energy recovery and smaller parasitic power requirements. In addition, we find the pressure dependence of the system performance to determine the optimal combustor operating pressure for this cycle.
(cont.) We calculate the energy requirements of each unit and determine the pressure dependence of the water-condensing thermal energy recovery and its relation to the gross power output. Furthermore, a sensitivity analysis is conducted on important operating parameters including combustor temperature, Heat Recovery Steam Generator outlet temperature, oxygen purity and oxygen concentration in the flue gases. A cost analysis of the proposed system is also conducted so as to provide preliminary cost estimates.
by Jongsup Hong.
S.M.
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Hong, Jongsup. „Numerical simulations of ion transport membrane oxy-fuel reactors for CO₂ capture applications“. Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81700.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 185-190).
Numerical simulations were performed to investigate the key features of oxygen permeation and hydrocarbon conversion in ion transport membrane (ITM) reactors. ITM reactors have been suggested as a novel technology to enable air separation and fuel conversion to take place simultaneously in a single unit. Possessing the mixed ionic and electronic conductivity, perovskite membranes or ion transport membranes permeate selectively oxygen ions from the air (feed) side to the sweep gas or reactive gas (permeate) side of the membrane, driven by the oxygen chemical potential gradient across the membrane at elevated temperature. When a fuel such as methane is introduced into the permeate side as a sweep gas, hydrocarbon oxidation reactions occur by reacting the fuel with the permeated oxygen. The fuel can be partially reformed, completely oxidized or converted to produce higher hydrocarbons. To utilize this technology more effectively, it is necessary to develop a better understanding of oxygen transport and hydrocarbon conversion in the immediate vicinity of the membrane or on its surface. In this thesis, a planar, finite-gap stagnation flow configuration was used to model and examine these processes. A spatially resolved physical model was formulated and used to parameterize an oxygen permeation flux expression in terms of the oxygen concentrations at the membrane surface given data on the bulk concentration. The parameterization of the permeation flux expression is necessary for cases when mass transfer limitations on the permeate side are important and for reactive flow modeling. At the conditions relevant for ITM reactor operation, the local thermodynamic state should be taken into account when the oxygen permeation rate is examined, which has been neglected. To elucidate this, the dependency of oxygen transport and fuel conversion on the geometry and flow parameters including the membrane temperature, air and sweep gas flow rates, oxygen concentration in the feed air and fuel concentration in the sweep gas was discussed. The reaction environment on the sweep side of an ITM was characterized. The spatially resolved physical model was used to predict homogeneous-phase fuel conversion processes and to capture the important features (e.g., the location, temperature, thickness and structure of a flame) of laminar oxy-fuel diffusion flames stabilized on the sweep side. The nature of oxygen permeation does not enable pre-mixing of fuel and oxidizer (i.e., sweep gas and permeated oxygen), establishing non-premixed flames. In oxy-fuel combustion applications, the sweep side is fuel-diluted with CO₂ or/and H₂O, and the entire unit is preheated to achieve a high oxygen permeation flux. This study focused on the flame structure under these conditions and specifically on the chemical effect of CO₂ dilution. The interactions between oxygen permeation and homogeneous-phase fuel oxidation reactions on the sweep side of an ITM were examined. Within ITM reactors, the oxidizer flow rate, i.e., the oxygen permeation flux, is not a pre-determined quantity, since it depends on the oxygen partial pressures on the air and sweep sides and the membrane temperature. Instead, it is influenced by the hydrocarbon oxidation reactions that are also dependent on the oxygen permeation rate, the initial conditions of the sweep gas, i.e., the fuel concentration, flow rate and temperature, and the diluent. A parametric study with respect to key operating conditions, which include the fuel concentration in the sweep gas, its flow rate and temperature and the geometry, was conducted to investigate their interactions. The catalytic kinetics of heterogeneous oxygen surface exchange and fuel oxidation for a perovskite membrane in terms of the thermodynamic state in the immediate vicinity of or on the membrane surface was investigated. Perovskite membranes have been shown to exhibit both oxygen perm-selectivity and catalytic activity for hydrocarbon conversion. However, a description of their catalytic surface reactions is still required. The kinetic parameters for heterogeneous oxygen surface exchange and catalytic fuel conversion reactions were inferred, based on permeation rate measurements and a spatially resolved physical model that incorporates detailed chemical kinetics and transport in the gas-phase. It is shown that the local thermodynamic state at the membrane surface should be accounted for when constructing and examining membrane permeation and heterogeneous chemistry. The significance of modeling both homogeneous and heterogeneous chemistry and their coupling when examining the results was discussed.
by Jongsup Hong.
Ph.D.
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Lassagne, Olivier. „Analyse techno-économique de l'implantation de la capture du CO₂ dans une aluminerie“. Master's thesis, Université Laval, 2013. http://hdl.handle.net/20.500.11794/24766.
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Comme de nombreuses industries, les alumineries se retrouvent face au nouveau défi de réduction des émissions de gaz à effet de serre (GES). La capture du CO₂ émis par les cuves d'électrolyse permettrait de réduire drastiquement les GES sans nécessiter des changements importants de la technologie actuelle de production. Ce travail présente deux analyses technico-économiques de la capture du CO₂ émis par les cuves d'électrolyse afin d'en évaluer la faisabilité. La première étude vérifie si la capture par la monoethanolamine (MEA), une alkano amine primaire couramment employée pour la séparation des gaz acides, est techniquement possible et économiquement intéressante dans une aluminerie. L'effet du taux de ventilation des cuves d'électrolyse a été étudié afin d'augmenter la concentration du CO₂ dans les effluents gazeux. De plus, la possibilité d'une intégration thermique a été prise en considération, pour permettre d'évaluer dans quels secteurs les rejets thermiques d'une aluminerie sont compatibles avec les besoins énergétiques de l'installation de capture. Il ressort de cette première analyse qu'une concentration en CO₂ de 4 vol% dans les effluents gazeux des cuves d'électrolyse est la configuration la plus adéquate techniquement et économiquement. Le coût de la capture est estimé à 107 $/tonne de C0₂ évité, correspondant à 100 $/tonne d'aluminium produit. Une intégration thermique appropriée permettrait théoriquement de réduire de 58% les coûts de la capture. La seconde étude évalue la possibilité de l'utilisation d'une solution à base d'aminé à encombrement stérique, afin de rendre la capture plus attractive économiquement. Le choix est porté sur l'utilisation d'un mélange de 2-amino 2-methyl 1-propranol (AMP) et de piperazine (PZ), un solvant moins énergivore. Pour l'étude, la configuration avec une concentration en CO₂ de 4 vol% dans les effluents gazeux a été utilisée. Une composition massique de 8% en PZ et de 32% en AMP dans le solvant s'est avérée être la meilleure configuration. L'utilisation du mélange AMP/PZ permet de réduire de 25% le coût du capital et de 29% les coûts opératoires par rapport à la MEA (65 $/tonne de CO₂ évité par rapport à 107 $/tonne pour la MEA). L'intégration thermique permet de réduire le coût de la capture à 58 $/tonne de CO₂ évité.
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Nourouzilavasani, Samira. „Technico-economic evaluation of bitumen-coke integrated gasification combined cycle with CO₂ capture“. Master's thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25542/25542.pdf.
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Miocic, Johannes Marijan. „A study of natural CO₂ reservoirs : mechanisms and pathways for leakage and implications for geologically stored CO₂“. Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/17881.
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Carbon Capture and Storage (CCS) is a suite of technologies available to directly reduce carbon dioxide (CO2) emissions to the atmosphere from fossil fuelled power plants and large industrial point sources. For a safe deployment of CCS it is important that CO2 injected into deep geological formations does not migrate out of the storage site. Characterising and understanding possible migration mechanisms and pathways along which migration may occur is therefore crucial to ensure secure engineered storage of anthropogenic CO2. In this thesis naturally occurring CO2 accumulations in the subsurface are studied as analogue sites for engineered storage sites with respect to CO2 migration pathways and mechanisms that ensure the retention of CO2 in the subsurface. Geological data of natural CO2 reservoirs world-wide has been compiled from published literature and analysed. Results show that faults are the main pathways for migration of CO2 from subsurface reservoirs to the surface and that the state and density of CO2, pressure of the reservoir, and thickness of the caprock influence the successful retention of CO2. Gaseous, low density CO2, overpressured reservoirs, and thin caprocks are characteristics of insecure storage sites. Two natural CO2 reservoirs have been studied in detail with respect to their fault seal properties. This includes the first study of how fault rock seals behave in CO2 reservoirs. It has been shown that the bounding fault of the Fizzy Field reservoir in the southern North Sea can with hold the amount of CO2 trapped in the reservoir at current time. A initially higher gas column would have led to across fault migration of CO2 as the fault rock seals would not have been able to withhold higher pressures. Depending on the present day stress regime the fault could be close to failure. At the natural CO2 reservoir of St. Johns Dome, Arizona, migration of CO2 to the surface has been occurring for at least the last 500 ka. Fault seal analysis shows that this migration is related to the fault rock composition and the orientation of the bounding fault in the present day stress field. Using the U-Th disequilibrium method the ages of travertine deposits of the St. Johns Dome area have been determined. The results illustrate that along one fault CO2 migration took place for at least 480 ka and that individual travertine mounds have had long lifespans of up to ~350 ka. Age and uranium isotope trends along the fault have been interpreted as signs of a shrinking CO2 reservoir. The amount of CO2 calculated to have migrated out of the St. Johns Dome is up to 113 Gt. Calculated rates span from 5 t/yr to 30,000 t/yr and indicate that at the worst case large amounts of CO2 can migrate rapidly from the subsurface reservoir along faults to the surface. This thesis highlights the importance of faults as fluid pathways for vertical migration of CO2. It has been also shown that they can act as baffles for CO2 migration and that whether a fault acts as pathway or baffle for CO2 can be predicted using fault seal analysis. However, further work is needed in order to minimise the uncertainties of fault seal analysis for CO2 reservoirs.
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Zhu, Yibing. „CO2 Adsorption on amine-coated elastomers: an IR study“. University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1522426264764055.
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Occhineri, Lorenzo. „Technical and economic assessments of CO2 capture processes in power plants“. Thesis, Mälardalen University, School of Sustainable Development of Society and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-4705.
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Bhaduri, Gaurav Ashok. „Catalytic enhancement of hydration of CO₂ using nickel nanoparticles for carbon capture and storage“. Thesis, University of Newcastle upon Tyne, 2018. http://hdl.handle.net/10443/4135.
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The capture and storage of atmospheric CO2 as mineral carbonates, is one of the safest ways to combat global warming. The slow CO2 hydration rate is one limitation of the mineralization process. The current study presents the discovery of nickel nanoparticles (NiNPs) as a catalyst for enhancing the rate of CO2 hydration for mineralization carbon capture and storage. The NiNPs at an optimum concentration of 30 ppm, increased the saturation concentration by three folds as compared with deionized water alone. The mechanism of the reaction on NiNPs surface is also proposed. The kinetics of catalysis of CO2 hydration was additionally studied using stopped flow spectrophotometery and pH changes in buffer solution upon addition of saturated CO2 solution. To distinguish between physical gas-liquid transfer and catalysis, other inorganic nanoparticles (NiO and Fe2O3) have been studied. The effect of CO2 partial pressure on NiNPs catalysis was studied. Nickel nanowires (NiNWs) were synthesised and tested for catalysis of CO2 hydration. The photocatalytic activity of NiNPs was evaluated under artificial solar irradiation compared with that in the dark. The results suggest that the surface plasmonic resonance (SPR) of NiNPs enhances the rate of water dissociation on the NiNPs surface leading to higher rate of CO2 hydration under solar irradiation. The effect of temperature on the catalytic activity of NiNPs is evaluated. Optimum activity was observed at room temperature (20-30 °C). Application of NiNPs catalysis was investigated for CaCO3 precipitation and the rate of CO2 absorption in 50 wt% carbonate solutions. Vapour-liquid equilibrium studies of CO2-H2O in presence of nanoparticles (Ni, Fe2O3 and NiO) found that ii the presence of nanoparticles decreases the surface tension of DI water, responsible for the increase in CO2 saturation concentration. Additionally a novel method for mineralization of CO2 using gypsum and sodium chloride was developed including design of a customized reactor.
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Hasib-ur-Rahman, Muhammad. „CO₂ capture using alkanolamine/room-temperature ionic liquid blends : absorption, regeneration, and corrosion aspects“. Doctoral thesis, Université Laval, 2013. http://hdl.handle.net/20.500.11794/24209.
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Le réchauffement climatique, résultant essentiellement des émissions anthropiques de dioxyde de carbone, demeure un sujet de grande préoccupation. Le captage et la séquestration du dioxyde de carbone est une solution viable permettant de prévoir une baisse des émissions de CO2 issues des importantes sources ponctuelles qui impliquent la combustion des carburants fossiles. Dans cette perspective, les systèmes aqueux d’alcanolamines offrent une solution prometteuse à court terme pour la capture du CO2 dans les installations de production d'électricité. Cependant, ces systèmes sont confrontés à divers accrocs opératoires tels que les limitations d’équilibre, les grandes quantités d’énergie requises pour la régénération, les pertes en solvant et la corrosion prononcée des installations, pour ne citer que ces quelques inconvénients. L’eau étant la principale cause de ces complications, une mesure à prendre pourrait être le remplacement de la phase aqueuse par un solvant plus stable. Les liquides ioniques à température ambiante, dotés d’une haute stabilité thermique et pratiquement non-volatils émergent en tant que candidats prometteurs. De plus, grâce à leur nature ajustable, ils peuvent être apprêtés conformément aux exigences du procédé. La substitution de la phase aqueuse dans les processus utilisant l’alcanolamine par les liquides ioniques à température ambiante ouvre une opportunité potentielle pour une capture efficace du CO2. Un aspect remarquable de ces systèmes serait la cristallisation du produit résultant de la capture du CO2 (c-à-d, le carbamate) au sein même du liquide ionique qui non seulement déjouerait les contraintes d’équilibre mais également pourvoirait une opportunité intéressante pour la séparation des produits. Étant donné le peu d’information disponible dans la littérature sur la viabilité des systèmes utilisant la combinaison d’amine et de liquide ionique, l’étude proposée ici a pour but d’apporter une meilleure compréhension sur l’efficacité à séparer le CO2 d’un mélange de type postcombustion à travers une approche plus systématique. À cet effet, des liquides ioniques à base d’imidazolium ([Cnmim][Tf2N], [Cnmim][BF4], [Cnmim][Otf]) ont été choisis. Deux alcanolamines, à savoir, le 2-amino-2-methyl-1-propanol (AMP) et le diéthanolamine (DEA) ont été examinées en détail afin d’explorer la capture du CO2 et les possibilités de régénération qu’offre un système amine-liquide ionique. Les résultats ont révélé l’intérêt de la combinaison DEA-liquide ionique étant donné que ce système pourrait aider à réduire de manière significative l’écart entre les températures d’absorption et de régénération, promettant ainsi une perspective attrayante en termes d’économie d’énergie. En outre, les liquides ioniques ont également été scrutés du point de vue de leur nature hydrophobe/hydrophile afin d’étudier le comportement corrosif du mélange amine-liquide ionique au contact d’échantillons d’acier au carbone. Bien que l’utilisation des liquides ioniques hydrophiles ait aidé à abaisser la vitesse de corrosion jusqu’à concurrence de 72%, l’emploi de liquides ioniques hydrophobes s’avère plus efficace, car annulant quasiment le phénomène de corrosion même dans un environnement riche en CO2. Dans le cas des mélanges immiscibles comme DEA-[hmim][Tf2N], une agitation continue s’avère nécessaire afin d’assurer une dispersion prolongée des gouttelettes d’amine émulsifiées au sein de liquides ioniques et ainsi atteindre une vitesse de capture optimale.Global warming, largely resulting from anthropogenic emissions of carbon dioxide, continues to remain a matter of great concern. Carbon capture and storage (CCS) is a viable solution to ensure a prevised fall in CO2 emissions from large point sources involving fossil fuel combustion. In this context, aqueous alkanolamine systems offer a promising near-term solution for CO2 capture from power generation facilities. However, these face several operational hitches such as equilibrium limitations, high regeneration energy requirement, solvent loss, and soaring corrosion occurrence. The main culprit in this respect is water and, accordingly, one feasible practice may be the replacement of aqueous phase with some stable solvent. Room-temperature ionic liquids (RTILs), with high thermal stability and practically no volatility, are emerging as promising aspirants. Moreover, owing to the tunable nature of ionic liquids, RTIL phase can be adapted in accordance with the process requirements. Replacing aqueous phase with RTIL in case of alkanolamine based processes provided a potential opportunity for efficient CO2 capture. The most striking aspect of these schemes was the crystallization of CO2-captured product (carbamate) inside the RTIL phase that not only helped evade equilibrium constraints but also rendered a worthy opportunity of product separation. Since there is little information available in the literature about the viability of amine-RTIL systems, the proposed research was aimed at better understanding CO2 separation proficiency of these fluids through a more systematic approach. Imidazolium RTILs ([Cnmim][Tf2N], [Cnmim][BF4], [Cnmim][Otf]) were chosen for this purpose. Two alkanolamines, 2-amino-2-methyl-1-propanol (AMP) and diethanolamine (DEA) were examined in detail to explore CO2 capture and regeneration capabilities of amine-RTIL systems. The results revealed the superiority of DEA-RTIL combination as this scheme could help significantly narrow the gap between absorption and regeneration temperatures thus promising a sparkling prospect of attenuating energy needs. Furthermore, ionic liquids were scrutinized in reference to their hydrophobic/hydrophilic nature to study the corrosion behaviour of carbon steel in amine-RTIL media. Though hydrophilic ionic liquids helped decrease corrosion occurrence up to 72%, hydrophobic RTIL appeared to be the most effective in this regard, virtually negating the corrosion phenomenon under CO2 rich environment. In case of immiscible blends like DEA-[hmim][Tf2N], continual agitation appeared to be a necessity to ensure a prolonged dispersion of amine in the RTIL phase and, thereby, to attain an optimal capture rate.
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Koumpouras, Georgios. „Mathematical modelling of a low-temperature hydrogen production process with in situ CO₂ capture“. Thesis, Imperial College London, 2008. http://hdl.handle.net/10044/1/8211.
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Tarun, Cynthia. „Techno-Economic Study of CO2 Capture from Natural Gas Based Hydrogen Plants“. Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2837.
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As reserves of conventional crude oil are depleted, there is a growing need to develop unconventional oils such as heavy oil and bitumen from oil sands. In terms of recoverable oil, Canadian oil sands are considered to be the second largest oil reserves in the world. However, the upgrading of bitumen from oil sands to synthetic crude oil (SCO) requires nearly ten times more hydrogen (H2) than the conventional crude oils. The current H2 demand for oil sands operations is met mostly by steam reforming of natural gas. With the future expansion of oil sands operations, the demand of H2 for oil sand operations is likely to quadruple in the next decade. As natural gas reforming involves significant carbon dioxide (CO2) emissions, this sector is likely to be one of the largest emitters of CO2 in Canada. In the current H2 plants, CO2 emissions originate from two sources, the combustion flue gases from the steam reformer furnace and the off-gas from the process (steam reforming and water-gas shift) reactions. The objective of this study is to develop a process that captures CO2 at minimum energy penalty in typical H2 plants.
The approach is to look at the best operating conditions when considering the H2 and steam production, CO2 production and external fuel requirements. The simulation in this study incorporates the kinetics of the steam methane reforming (SMR) and the water gas shift (WGS) reactions. It also includes the integration of CO2 capture technologies to typical H2 plants using pressure swing adsorption (PSA) to purify the H2 product. These typical H2 plants are the world standard of producing H2 and are then considered as the base case for this study. The base case is modified to account for the implementation of CO2 capture technologies. Two capture schemes are tested in this study. The first process scheme is the integration of a monoethanolamine (MEA) CO2 scrubbing process. The other scheme is the introduction of a cardo polyimide hollow fibre membrane capture process. Both schemes are designed to capture 80% of the CO2 from the H2 process at a purity of 98%.
The simulation results show that the H2 plant with the integration of CO2 capture has to be operated at the lowest steam to carbon (S/C) ratio, highest inlet temperature of the SMR and lowest inlet temperatures for the WGS converters to attain lowest energy penalty. H2 plant with membrane separation technology requires higher electricity requirement. However, it produces better quality of steam than the H2 plant with MEA-CO2 capture process which is used to supply the electricity requirement of the process. Fuel (highvale coal) is burned to supply the additional electricity requirement. The membrane based H2 plant requires higher additional electricity requirement for most of the operating conditions tested. However, it requires comparable energy penalty than the H2 plant with MEA-CO2 capture process when operated at the lowest energy operating conditions at 80% CO2 recovery.
This thesis also investigates the sensitivity of the energy penalty as function of the percent CO2 recovery. The break-even point is determined at a certain amount of CO2 recovery where the amount of energy produced is equal to the amount of energy required. This point, where no additional energy is required, is approximately 73% CO2 recovery for the MEA based capture plant and 57% CO2 recovery for the membrane based capture plant.
The amount of CO2 emissions at various CO2 recoveries using the best operating conditions is also presented. The results show that MEA plant has comparable CO2 emissions to that of the membrane plant at 80% CO2 recovery. MEA plant is more attractive than membrane plant at lower CO2 recoveries.
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Lacroix, Olivier. „CO₂ capture using immobilized carbonic anhydrase in Robinson-Mahoney basket and packed absorption column reactors“. Master's thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25183/25183.pdf.
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Tong, Zi Tong. „CO2 facilitated transport membranes for hydrogen purification and flue gas carbon capture“. The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu150051302573791.
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Hoteit, Ali. „Etude expérientale des mécanismes de capture de Co² par cycle calcium en lit fluidisé circulant“. Mulhouse, 2006. http://www.theses.fr/2006MULH0832.
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Les travaux menés dans cette thèse en partenariat avec le département R&D d'ALSTOM POWER BOILERS, CEMEX et l'ADEME, concernent l'étude expérimentale de différents phénomènes associés à la capture de CO2 par la chaux en lit fluidisé circulant. La taille des particules, la température et la concentration en CO2 du milieu ont une influence sur la réaction de calcination du calcaire. La réaction de carbonatation de la chaux formée n'est pas totale. Au cours des cycles successifs de calcination/carbonatation, les taux de carbonatation obtenus avec la chaux hydratée sont toujours plus élevés que ceux obtenus avec la chaux vive. Sous des conditions continuellement réductrices, la décomposition des sulfates présents dans les cendres de lit n'est pas totale. Cette décomposition est totale sous des cycles réduction/oxydation. Une modélisation du phénomène de calcination a permis de déterminer les constantes de vitesse intrinsèques de calcination et de carbonatationThe work undertaken in this Thesis in partnership with department R&D of ALSTOM POWER BOILERS, CEMEX and the ADEME, relates to the experimental study of various phenomena associated to CO2 capture under circulating fluidized bed conditions. The size of particles, temperature and the CO2 concentration have an influence on the limestone calcination reaction. The reaction of carbonation of lime is not total. During successive cycles of calcination/carbonatation, the rate of carbonation obtained with hydrated lime is increasingly higher than that obtained with the lime. Under continuously reducing conditions, the decomposition of sulphates present in the bed ashes is not total. This decomposition is total under reduction/oxydation cycles. A modeling of calcination allowed to determine the intrinsic kinetic constants of calcination and carbonation
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Zhang, Wei. „Simulation of Solid Oxide Fuel Cell - Based Power Generation Processes with CO2 Capture“. Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/946.
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The Solid Oxide Fuel Cell (SOFC) is a promising technology for electricity generation. It converts the chemical energy of the fuel gas directly to electricity energy and therefore, very high electrical efficiencies can be achieved. The high operating temperature of the SOFC also provides excellent possibilities for cogeneration applications. In addition to producing power very efficiently, the SOFC has the potential to concentrate CO2 with a minimum of an overall efficiency loss. Concentration of CO2 is a desirable feature of a power generation process so that the CO2 may be subsequently sequestered thus preventing its contribution to global warming. The primary purpose of this research project was to investigate the role of the SOFC technology in power generation processes and explore its potential for CO2 capture in power plants. This thesis introduces an AspenPlusTM SOFC stack model based on the natural gas feed tubular internal reforming SOFC technology. It was developed utilizing existing AspenPlusTM functions and unit operation models. This SOFC model is able to provide detailed thermodynamic and parametric analysis of the SOFC operation and can easily be extended to study the entire process consisting of the SOFC stack and balance of plant.
Various SOFC-based power generation cycles were studied in this thesis. Various options for concentrating CO2 in these power generation systems were also investigated and discussed in detail. All the processes simulations were implemented in AspenPlusTM extending from the developed natural gas feed tubular SOFC stack model. The study shows that the SOFC technology has a promising future not only in generating electricity in high efficiency but also in facilitating CO2 concentration, but the cost of the proposed processes still need be reduced so SOFCs can become a technical as well as economic feasible solution for power generation.
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Iloeje, Chukwunwike Ogbonnia. „Rotary (redox) reactor-based oxy combustion chemical looping power cycles for CO₂ capture : analysis and optimization“. Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104249.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 224-229).
A number of CO₂ capture-enabled power generation technologies have been proposed to address the negative environmental impact of CO₂ emission. An important barrier to adopting these technologies is the associated energy and economic penalties. Chemical-looping (CLC) is an oxycombustion technology that can significantly lower such penalties, utilizing a redox process to eliminate the need for an air separation unit and enable better energy integration. Conventional CLC employs two separate reactors, with metal oxide particles circulating pneumatically in-between, leading to significant irreversibility associated with reactor temperature difference. A rotary reactor, on the other hand, maintains near-thermal equilibrium between the two stages by thermally coupling channels undergoing oxidation and reduction. In this thesis, a multiscale analysis for assessing the integration of the rotary CLC reactor technology in power generation systems is presented. This approach employs a sequence of models that successively increase the resolution of the rotary reactor representation, ranging from interacting thermal reservoirs to higher fidelity quasi-steady state models, in order to assess the efficiency potential and perform a robust optimization of the integrated system. Analytical thermodynamic availability and ideal cycles are used to demonstrate the positive impact of reactor thermal coupling on system efficiency. Next, detailed process flow-sheet models in which the rotary reactor is modeled as a set of interacting equilibrium reactors are used to validate the analytical model results, identify best cycle configurations and perform preliminary parametric analysis for between the reactor and the system while maintaining computational efficiency, an intermediate fidelity model is developed, retaining finite rate surface kinetics and internal heat transfer within the reactor. This model is integrated with a detailed system model and used for optimization, parametric analysis and characterization of the relative techno-economic performance of different oxygen carrier options for thermal plants integrated with the rotary CLC reactor. Results show that thermal coupling in the redox process increases the efficiency by up to 2% points for combined, recuperative and hybrid cycles. The studies also show that the thermal efficiency is a function of the reactor purge steam demand, which depends on the reactivity of the oxygen carrier. While purge steam constitutes a monotonic parasitic loss for the combined cycle, for recuperative and hybrid cycles, it raises the efficiency as long as the steam demand is less than a threshold value. This relationship between reactivity and system efficiency provides a useful selection criteria for the oxygen carrier material. Optimization results based on efficiency and levelized cost of electricity (LCOE) identify nickel-based oxygen carriers as the most suitable for the rotary reactor because its high reactivity ensures low steam demand and reactor cost. Compared to nickel, maximum efficiency and minimum LCOE are respectively 7% lower and 40% higher for a copper-based system; iron-based systems have 4% higher maximum efficiency and 7% higher minimum LCOE. This study also showed that optimal efficiency generally has an inverse profile to that for the optimized LCOE.
by Chukwunwike Ogbonnia Iloeje.
Ph. D.
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Long, Henry A. III. „Analysis of Biomass/Coal Co-Gasification for Integrated Gasification Combined Cycle (IGCC) Systems with Carbon Capture“. ScholarWorks@UNO, 2011. http://scholarworks.uno.edu/td/1371.
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In recent years, Integrated Gasification Combined Cycle Technology (IGCC) has become more common in clean coal power operations with carbon capture and sequestration (CCS). Great efforts have been spent on investigating ways to improve the efficiency, reduce costs, and further reduce greenhouse gas emissions. This study focuses on investigating two approaches to achieve these goals. First, replace the subcritical Rankine steam cycle with a supercritical steam cycle. Second, add different amounts of biomass as feedstock to reduce emissions. Finally, implement several types of CCS, including sweet- and sour-shift pre-combustion and post-combustion.
Using the software, Thermoflow®, this study shows that utilizing biomass with coal up to 50% (wt.) can improve the efficiency, and reduce emissions: even making the plant carbon-negative when CCS is used. CCS is best administered pre-combustion using sour-shift, and supercritical steam cycles are thermally and economically better than subcritical cycles. Both capital and electricity costs have been presented.
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Silva, Mojica Ernesto. „CO2 and SO2 Capture by Aromatic and Aliphatic Amine Sorbents“. University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1312042029.
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Kulkarni, Ambarish R. „Multiscale modeling of nanoporous materials for adsorptive separations“. Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53053.
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The detrimental effects of rising CO₂ levels on the global climate have made carbon abatement technologies one of the most widely researched areas of recent times. In this thesis, we first present a techno-economic analysis of a novel approach to directly capture CO₂ from air (Air Capture) using highly selective adsorbents. Our process modeling calculations suggest that the monetary cost of Air Capture can be reduced significantly by identifying adsorbents that have high capacities and optimum heats of adsorption. The search for the best performing material is not limited to Air Capture, but is generally applicable for any adsorption-based separation. Recently, a new class of nanoporous materials, Metal-Organic Frameworks (MOFs), have been widely studied using both experimental and computational techniques. In this thesis, we use a combined quantum chemistry and classical simulations approach to predict macroscopic properties of MOFs. Specifically, we describe a systematic procedure for developing classical force fields that accurately represent hydrocarbon interactions with the MIL-series of MOFs using Density Functional Theory (DFT) calculations. We show that this force field development technique is easily extended for screening a large number of complex open metal site MOFs for various olefin/paraffin separations. Finally, we demonstrate the capability of DFT for predicting MOF topologies by studying the effect of ligand functionalization during CuBTC synthesis. This thesis highlights the versatility and opportunities of using multiscale modeling approach that combines process modeling, classical simulations and quantum chemistry calculations to study nanoporous materials for adsorptive separations.