The Experts below are selected from a list of 74115 Experts worldwide ranked by ideXlab platform
Calin-cristian Cormos - One of the best experts on this subject based on the ideXlab platform.
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evaluation of syngas based chemical looping applications for hydrogen and power co generation with ccs
International Journal of Hydrogen Energy, 2012Co-Authors: Calin-cristian CormosAbstract:Abstract This paper evaluates hydrogen and power co-generation based on coal-gasification fitted with an iron-based chemical looping system for carbon capture and storage (CCS). The paper assess in details the whole hydrogen and power co-production chain based on coal gasification. Investigated plant concepts of syngas-based chemical looping generate about 350–450 MW net electricity with a flexible output of 0–200 MWth hydrogen (based on lower heating value) with an almost total decarbonisation rate of the coal used. The paper presents in details the plant concepts and the methodology used to evaluate the performances using critical design factors like: gasifier selection criteria for chemical looping applications, influence of gasifier feeding system (dry fed vs. slurry fed), heat and power integration analysis as potential ways to increase the overall energy efficiency, hydrogen and carbon dioxide quality specifications considering the use of hydrogen in transport (fuel cells) and carbon dioxide storage in Geological Formation or used for EOR. The results show that syngas-based chemical looping systems ensure lower carbon capture energy penalties and higher overall plant energy efficiencies than more technologically mature capture methods (e.g. pre- and post-combustion capture based on gas–liquid absorption).
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Hydrogen production from fossil fuels with carbon capture and storage based on chemical looping systems
International Journal of Hydrogen Energy, 2011Co-Authors: Calin-cristian CormosAbstract:This paper analyzes innovative processes for producing hydrogen from fossil fuels conversion (natural gas, coal, lignite) based on chemical looping techniques, allowing intrinsic CO2 capture. This paper evaluates in details the iron-based chemical looping system used for hydrogen production in conjunction with natural gas and syngas produced from coal and lignite gasification. The paper assesses the potential applications of natural gas and syngas chemical looping combustion systems to generate hydrogen. Investigated plant concepts with natural gas and syngas-based chemical looping method produce 500 MW hydrogen (based on lower heating value) covering ancillary power consumption with an almost total decarbonisation rate of the fossil fuels used. The paper presents in details the plant concepts and the methodology used to evaluate the performances using critical design factors like: gasifier feeding system (various fuel transport gases), heat and power integration analysis, potential ways to increase the overall energy efficiency (e.g. steam integration of chemical looping unit into the combined cycle), hydrogen and carbon dioxide quality specifications considering the use of hydrogen in transport (fuel cells) and carbon dioxide storage in Geological Formation or used for EOR.
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assessment of hydrogen and electricity co production schemes based on gasification process with carbon capture and storage
International Journal of Hydrogen Energy, 2009Co-Authors: Calin-cristian CormosAbstract:Abstract Through gasification, a solid feedstock is partially oxidized with oxygen and steam to produce syngas which can be used for conversion into different valuable compounds (e.g. hydrogen) or to generate power in a combined cycle gas turbine (CCGT). Integrated gasification combined cycle (IGCC) is one of power generation technologies having the highest potential for carbon capture with low penalties in efficiency and cost. This paper assesses from technical point of view the transFormation, through gasification, of coal with or without addition of renewable energy sources or solid waste into decarbonised energy vectors (power, hydrogen) simultaneous with carbon capture and storage (CCS). Investigated plant concepts produce a flexible ratio of power and hydrogen in the range of 400 MW electricity and 0–200 MW hydrogen with 90% carbon capture rate. The paper describes the methodology to evaluate the plant performances using critical design factors like: fuel selection criteria, choice of gasification reactor, heat and power integration, flexibility analysis, carbon capture and storage (CCS), H2 and CO2 quality specifications considering the use of hydrogen in transport sector (fuel cells) and carbon dioxide storage in Geological Formation or using for Enhanced Oil Recovery (EOR).
L Font - One of the best experts on this subject based on the ideXlab platform.
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radon levels in groundwaters and natural radioactivity in soils of the volcanic region of la garrotxa spain
Journal of Environmental Radioactivity, 2014Co-Authors: V Moreno, Joan Bach, C Baixeras, L FontAbstract:Abstract Groundwater radon level and soil radionuclide concentration have been measured in the volcanic region of La Garrotxa (Catalonia, Spain) to further research on the origin and dynamics of high radon levels over volcanic materials found in this region. Water samples from different aquifers have been collected from wells and springs and the water radon levels obtained have been lower than 30 Bq l −1 . Soil samples have been collected from different Geological Formations (volcanic and non-volcanic), being Quaternary sedimentary deposits those that have presented the highest mean values of 40 K, 226 Ra and 232 Th concentrations (448 ± 70 Bq kg −1 , 35 ± 5 Bq kg −1 and 38 ± 5 Bq kg −1 , respectively). Additionally, indoor/outdoor terrestrial radiation absorbed dose rate in air have been measured to better characterize the region from the radiological point of view. Terrestrial radiation absorbed dose rates measurement points have been chosen on the basis of Geological and demographical considerations and the results obtained, from 27 to 91 nGy h −1 , show a clear relation with Geological Formation materials. The highest terrestrial gamma absorbed dose rate is observed over Quaternary sedimentary deposits as well. All these results help to better understand previous surveys related with indoor and outdoor radon levels and to reinforce the hypotheses of a radon transport through the fissure network.
Cs Szabo - One of the best experts on this subject based on the ideXlab platform.
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a new method for the determination of geophysical parameters by radon concentration measurements in bore hole
Journal of Environmental Radioactivity, 2008Co-Authors: B Papp, F Deak, A Horvath, A Kiss, G Rajnai, Cs SzaboAbstract:We propose a new method to measure the (222)Rn concentration in a closed bore-hole and to use the results for estimation of the diffusion parameter and the average radium content of the surrounding Geological Formations. In a closed bore-hole, only several meters from the surface, the radon concentration is rather constant (in the +/-15% range) under different meteorological conditions. The inflow of radon gas, after removing the radon from the bore-hole by dry nitrogen, shows characteristic time-dependence, which is determined by the diffusion parameter for radon in the surrounding environment. The experimental data were well described by a straightforward model calculation. From the results estimate can be given for the diffusion parameter and for the average radium content of the surrounding Geological Formation.
Kristina Rasmusson - One of the best experts on this subject based on the ideXlab platform.
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small scale co2 injection into a deep Geological Formation at heletz israel
Energy Procedia, 2012Co-Authors: Auli Niemi, Jacob Bensabat, Fritjof Fagerlund, Martin Sauter, Julia Ghergut, Tobias Licha, Thomas Fierz, G Wiegand, Maria Rasmusson, Kristina RasmussonAbstract:This paper presents the experimental plans and designs as well as examples of predictive modeling of a pilot-scale CO2 injection experiment at the Heletz site (Israel). The overall objective of the experiment is to find optimal ways to characterize CO2 -relevant in-situ medium properties, including field-scale residual and dissolution trapping, to explore ways of characterizing heterogeneity through joint analysis of different types of data, and to detect leakage. The experiment will involve two wells, an injection well and a monitoring well. Prior to the actual CO2 injection, hydraulic, thermal and tracer tests will be carried out for standard site characterization. The actual CO2 injection experiments will include (i) a single well injection-withdrawal experiment, with the main objective to estimate in-situ residual trapping and (ii) a two-well injection-withdrawal test with injection of CO2 in a dipole mode (injection of CO2 in one well with simultaneous withdrawal of water in the monitoring well), with the objective to understand the CO2 transport in heterogeneous geology as well as the associated dissolution and residual trapping. Tracers will be introduced in both experiments to further aid in detecting the development of the phase composition during CO2 transport. Geophysical monitoring will also be implemented. By means of modeling, different experimental sequences and injection/withdrawal patterns have been analyzed, as have parameter uncertainties. The objectives have been to (i) evaluate key aspects of the experimental design, (ii) to identify key parameters affecting the fate of the CO2 and (iii) to evaluate the relationships between measurable quantities and parameters of interest.
Ruben Juanes - One of the best experts on this subject based on the ideXlab platform.
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residual trapping solubility trapping and capillary pinning complement each other to limit co2 migration in deep saline aquifers
Energy Procedia, 2014Co-Authors: Benzhong Zhao, Christopher W Macminn, Ruben JuanesAbstract:Abstract We derive a theoretical model for the post-injection migration of a CO2 gravity current in a confined, sloping aquifer under the influence of residual trapping, solubility trapping, and capillary pinning. The resulting model consists of two coupled partial differential equations that describe the local thickness of the buoyant CO2 current and the thickness of the mound of brine saturated with dissolved CO2 as a function of time. We apply this model to a representative Geological Formation and provide estimates of the lifetime of the buoyant CO2 current and its maximum migration distance. Our analysis shows that residual trapping, solubility trapping, and capillary pinning complement each other in limiting the ultimate migration distance of CO2 gravity currents. The relative contribution of residual trapping, solubility trapping, and capillary pinning varies as a function of the injection volume. Our model can be used as a screening tool to evaluate the potential of deep saline aquifers for large-scale CO2 sequestration.