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TitleCalcium looping in solar power generation plants
Publication TypeJournal Article
Year of Publication2012
AuthorsEdwards, S.E.B., and Materić V.
JournalSolar Energy
Pagination2494 - 2503
Date Published2012
ISSN0038092X (ISSN)
KeywordsActivity levels, Baseload, calcification, Calcination, Calciners, Calcium, Calcium carbonate, CaO/CaCO <sub>3</sub>, Capital costs, Carbonation, Concentrated solar power, Efficiency, Electric efficiency, Existing systems, First order, Fluidised bed, Fluidized beds, Fused salts, Gas turbines, Heat storage, High energy densities, High temperature operations, Micro grid, Models, Molten salt, numerical model, power generation, Power generation plants, power plant, Power production, salt, Solar concentrators, Solar heat, solar power, Solar power generation, Solar power plants, Solar thermal power plants, Sorption, Storage volumes, temperature effect, Thermal storage, Transportation system, turbine, Variable demands
AbstractThe use of a calcium looping based process as a thermal storage and transportation system for concentrated solar power plants is proposed in this work. This system exploits the reversible calcination-carbonation reaction of limestone and lime. Concentrated solar heat is used to calcine CaCO 3, which is then released as required by carbonating the resulting CaO. The CaO/CaCO 3 system has a high energy density and its high temperature operation allows the use of a gas turbine for power production. This paper presents a first order evaluation of the potential of this application of calcium looping, with particular consideration given to carbonation activity of the sorbent. A model including a solar calciner and a pressurised fluidised bed carbonator feeding a gas turbine in an open Brayton cycle has been developed. Results from the model indicate that electric efficiencies of 40-50% could be achieved with sorbent carbonation activities between 15% and 40%. Higher sorbent activity levels do not affect efficiency but would lead to lower capital costs. According to the model, CaO activity levels above 17% lead to significant reductions in the required storage volume over existing systems, such as molten salts. In principle, high efficiency and smaller footprint solar thermal power plants are possible with calcium looping. Such plants would have no process use of water and could be used as baseload, variable demand load or microgrid systems. © 2012 Elsevier Ltd.

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