| 1. |
- Bryngelsson, Hanna, et al.
(författare)
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How dynamic is the SEI?
- 2007
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 174:2, s. 970-975
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Tidskriftsartikel (refereegranskat)abstract
- The surface chemistry of graphite and intermetallic AlSb has been studied by XPS (X-ray photoelectron spectroscopy) in a Li-ion battery context using LiPF6 in EC/DEC as electrolyte. The main results for graphite are as follows: the SEI (solid electrolyte interphase) is different for the lithiated state after 3 cycles (0.01 V) compared to the delithiated state (1.5 V); after 50 cycles the SEI is thicker; there are more Li2CO3 or semi-carbonates on the surface of the delithiated sample (1.5 V) than on the lithiated sample (0.01 V); LiF is continuously formed during the first cycles but a steady state is reached after 50 cycles; a new peak in the C 1s spectra indicating a fluorine-containing compound is found at high photon energies (292 eV). The main results for AlSb are as follows: the SEI is different for the lithiated state (0.01 V) compared to the delithiated state (1.2 V) after 3 cycles; after 50 cycles the surface layer thickness is slightly larger but significantly thinner than for graphite; contrary to graphite, more Li2CO3 or semi-carbonates are found on the surface of the lithiated sample; also here a new peak indicating a fluorine-containing compound is found in the C 1s spectra at 292 eV. The general result is that the SEI has many similar features between graphite and AlSb but also important differences. The carbonaceous layer is dynamically shifting in chemical composition during cycling for both samples.
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| 2. |
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| 3. |
- Bryngelsson, Mårten, et al.
(författare)
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CO2 capture pilot test at a pressurized coal fired CHP plant
- 2009
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 1:1, s. 1403-1410
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Tidskriftsartikel (refereegranskat)abstract
- CO2 capture from pressurized flue gas using a variation of the hot potassium carbonate process has been demonstrated at a pilot plant with authentic flue gas from the Vartan combined heat and power plant in Stockholm. The plant has served as a proof of concept installation, and has confirmed that: i) the pre-treatment of the flue gas is adequate for protecting the absorbent from degradation, ii) the CO2 capture efficiency is high (> 98 %), iii) no harmful components are fed to the gas turbine, and iv) absorbent degradation is low (0.85 mole percent/month).
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| 4. |
- Bryngelsson, Mårten, et al.
(författare)
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Energy policy on shaky ground? : A study of CCS-scenarios
- 2009
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; :1, s. 4673-4680
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Tidskriftsartikel (refereegranskat)abstract
- Scenarios play an important role for the societal acceptance of CCS. This paper looks into influential reports containing CCS scenarios and analyses results, key assumptions and drivers for CCS' deployment. Significant uncertainties regarding CCS' development were in several cases excluded or marginalized. Despite these shortcomings, scenarios support a massive deployment of CCS and reflect an undivided optimism. If CCS would fail to meet the high expectations a backlash could follow. Indications were found that new scenarios including uncertainties are needed to balance this over-optimism. So-called unpleasant scenarios are often valuable in helping decision makers develop flexible strategies and policies.
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| 5. |
- Bryngelsson, Mårten, et al.
(författare)
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Feasibility study of CO2 removal from pressurized flue gas in a fully fired combined cycle : the Sargas project
- 2005
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Ingår i: Proceedings of the 18th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS. ; , s. 703-710
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Konferensbidrag (refereegranskat)abstract
- In this article a novel concept for CO2 removal from power plants is discussed from a systems perspective. The main advantage of the process is that the investment cost and the power penalty for CO2 removal can be substantially reduced compared to conventional combined cycles. The proposed technical solution comprises fully fired combined cycle, which minimizes the amount of flue gas. Furthermore, the CO2 absorption is performed at pressurized conditions prior to the expansion, which further enhances the CO2 removal. The modification of the power cycle and integration of absorption stages makes CO2 removal equipment much more compact and allows the use Of CO2 absorbents with lower heat demand for the regeneration. The partial pressure of CO2 is above atmospheric pressure and removal efficiencies above 95% can be obtained with potassium carbonate absorption (the Benfield process). The treated flue gas is then reheated and re-humidified before the expansion in the gas turbine. A Norwegian consortium has developed the concept and feasibility studies have been performed for 100 MW and 400 MW power plants based on natural gas in Norway. The produced carbon dioxide is intended for storage in the Norwegian oil and gas fields in order to enhance the oil recovery. The suggested localizations of the power plants have been chosen accordingly. The design study is based on the same gas turbine and steam cycle as used in the commercial Pressurized Fluidized Bed Combustion (PFBC) cycle. PFBC plants are presently fired with coal but the fluid bed combustor for coal will be replaced by a gas combustor if natural gas is used. A key advantage is that the process can be built solely from commercially available components. This report is an assessment of the features, capabilities, advantages and future possibilities of the suggested power cycle with integrated CO2 removal. A power plant for 100 MW power output and based on natural gas is considered suitable as a first demonstration plant to be built in Hammerfest, Norway. A permit application has been turned in. For such a demonstration plant the process simulations have indicated that an efficiency of about 40% can be obtained, including the penalties from CO2 capture and compression. Further improvements, e.g. supercritical steam cycle or more advanced gas turbine increases the efficiency and for a 400 MW power cycle a net efficiency of about 44-48% has been simulated (including CO2 capture and compression). The cycle may also be suitable for CO2 removal from coal-fired plants.
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| 6. |
- Bryngelsson, Mårten, et al.
(författare)
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The modelling of a hybrid combined cycle with pressurised fluidised bed combustion and CO2 capture
- 2009
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Ingår i: International journal of greenhouse gas control. - : Elsevier BV. - 1750-5836. ; 3:3, s. 255-262
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the possibility of capturing CO2 from flue gas under pressurised conditions, which could prove to be beneficial in comparison to working under atmospheric conditions. Simulations of two hybrid combined cycles with pressurised fluidised bed combustion and CO2 capture are presented. CO2 is captured from pressurised flue gas by means of chemical absorption after the boiler but before expansion. The results show a CO2 capture penalty of approximately 8 percentage points (including 90% CO2 capture rate and compression to 110 bar), which makes the efficiency for the best performing cycle 43.9%. It is 5.2 percentage points higher than the most probable alternative, i.e. using a natural gas fired combined cycle and a pulverised coal fired condensing plant separately with the same fuel split ratio. The largest part of the penalty is associated with the lower mass flow of flue gas after CO2 capture, which leads to a decrease in work output in the expander and potential for feed water heating. The penalty caused by the regeneration of absorbent is quite low, since the high pressure permits the use of potassium carbonate, which requires less regeneration heat than for example the more commonly proposed monoethanolamine. Although the efficiencies of the cycles look promising it will be important to perform a cost estimate to be able to make a fair comparison with other systems. Such a cost estimate has not been done in this study. A significant drawback of these hybrid cycles in that respect is the complex nature of the systems that will have a negative effect on the economy.
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| 7. |
- Grönkvist, Stefan, et al.
(författare)
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Oxygen efficiency with regard to carbon capture
- 2006
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 31:15, s. 3220-3226
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Tidskriftsartikel (refereegranskat)abstract
- Carbon capture is often discussed in the literature with the sole focus on power processes, despite the fact that carbon dioxide emissions from other sources are just as relevant for the impact on the atmosphere. Furthermore, some carbon capture methods are relatively inefficient when applied to power production processes. Carbon capture should preferably be performed where the cost is as low as possible, i.e. not necessarily from power production processes. As an example, carbon capture using combustion with pure oxygen is far more energy efficient if it is used together with lime kilns or cement kilns than together with power production processes. A new concept termed "oxygen efficiency" is introduced in this paper. It describes the amount of carbon dioxide that can potentially be captured per unit of oxygen. As such, the oxygen efficiency quantifies the value of a certain unit of oxygen for carbon capture reasons. The base concept is that the energy penalty for the production of one part of oxygen is the same no matter where it is produced; hence, if this unit of oxygen can be used to capture more carbon dioxide, it is more efficient. Typically, the oxygen efficiency would be five times greater for carbon capture when utilising pure oxygen together with cement kilns rather than together with methane-fired power plants. Furthermore, the concept of oxygen efficiency illustrates the importance of considering how carbon capture methods can be utilised in the most efficient way, in addition to evaluating which carbon capture method is the most suitable for a particular technology.
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| 8. |
- Grönkvist, Stefan, et al.
(författare)
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Oxygen efficiency with regards to carbon capture
- 2004
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Ingår i: Energy-Efficient, Cost-Effective and Environmentally-Sustainable Systems and Processes, Vols 1-3. - MEXICO : INST MEXICANO DEL PETROLEO. - 9684890273 ; , s. 487-496
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Konferensbidrag (refereegranskat)abstract
- Carbon capture is often discussed in the literature with the sole focus on power processes, despite the fact that carbon dioxide emissions from other sources are just as relevant for the impact oil the atmosphere. Furthermore, some carbon capture methods are relatively inefficient when applied to power production processes. Carbon capture should preferably be performed where the cost is as low as possible, i.e. not necessarily from power production processes. As all example, carbon capture using combustion with pure oxygen is far more energy efficient if it is used together with lime kilns or cement kilns than together with power production processes. A new concept termed "oxygen efficiency" is introduced in this paper. It describes the amount of carbon dioxide that can potentially be captured per unit of oxygen. As such, the oxygen efficiency quantifies the value of a certain unit of oxygen for carbon capture reasons. The base concept is that the energy penalty for the production of one part of oxygen is the same no matter where it is produced; hence, if this unit of oxygen call be used to capture more carbon dioxide, it is more efficient. Typically, the oxygen efficiency would be five times greater for carbon capture when utilising pure oxygen together with cement kilns rather than together with methane-fired power plants. Furthermore, the concept of oxygen efficiency illustrates the importance of considering how carbon capture methods can be utilised in the most efficient way, in addition to evaluating which carbon capture method is the most suitable for a particular technology.
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| 9. |
- Hansson, Anders, et al.
(författare)
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Attitudes regarding CO2 capture and storage from a Swedish perspective
- 2005
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Ingår i: Proceedings of the Fourth Annual Conference on Carbon Capture and Sequestration. ; , s. 1-16
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Konferensbidrag (refereegranskat)abstract
- This study examines the attitudes of Swedish politicians, scientists, NGOs and industry regarding CO2capture and storage (CCS), i.e. actors who possess knowledge about CCS today and will influence thepublic opinion of tomorrow. The study is unique since the phenomenological approach is seldom seenin this specific context. The empirical data is gathered through interviews and is structured andanalyzed in respect to expressed basic assumptions, systems view and a theoretical frameworkstemming from history of technology. From data, different ideal types are constructed - the CCSopponent, the CCS pragmatic and the CCS supporter. Results show a lot of skepticism and evenopposition to the technology among NGOs and politicians, while industry and scientists generally areproponents. The large group of pragmatics is especially interesting since it is presumed to take a standin the foreseeable future.Over time the energy politics in Sweden has been subject to intense controversies. Betweenthe 1960s and 1980s hydropower and nuclear power were heavily debated. With arguments stemmingfrom environmental protection the public opinion, represented by a wide array of strongorganizations, restricted the expansion of those power sources far below the originally plannedcapacity. Now this new technology, CCS, is about to enter the Swedish debate. It is a controversialtechnology with similar characteristics compared to its precedents regarding e.g. large-scale, risk, andlong-term storage, i.e. characteristics that led to the referendum deciding a nuclear power phase out.Unless a careful approach to implementing the technology, could CCS also be phased outprematurely? Will history repeat itself?The results should be seen from a Swedish point of view since Sweden has vast bio-fuel andhydropower resources, which together with an extensive amount of nuclear power makes CO2emissions per capita and GDP low, and the opposition against fossil fuels high.
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| 10. |
- Hansson, Anders, 1978-, et al.
(författare)
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Expert opinions on carbon dioxide capture and storage : a framing of uncertainties and possibilities
- 2009
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Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215 .- 1873-6777. ; 37:6, s. 2273-2282
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Tidskriftsartikel (refereegranskat)abstract
- There are many uncertainties and knowledge gaps regarding the development of carbon dioxide capture and storage (CCS)-e.g., when it comes to costs, life-cycle effects, storage capacity and permanence. In spite of these uncertainties and barriers, the CCS research community is generally very optimistic regarding CCS' development. The discrepancy between the uncertainties and the optimism is the point of departure in this study, which is based on interviews with 24 CCS experts. The aim is to analyse experts' framings of CCS with focus on two key aspects: (i) the function and potential of CCS and (ii) uncertainties. The optimism among the CCS experts is tentatively explained. The interpretative flexibility of CCS is claimed to be an essential explanation for the optimism. CCS is promoted from a wide variety of perspectives, e.g., solidarity and peace, bridge to a sustainable energy system, sustaining the modern lifestyle and compatibility with the fossil fuel lock-in. Awareness of the uncertainties and potential over-optimism is warranted within policy and decision making as they often rely on scientific forecasts and experts' judgements.
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