Constant rate thermal analysis for enhancing the long-term CO2 capture of CaO at Ca-looping conditions

Experimental results are reported on the (Ca-looping) multicyclic CO2 capture of CaO and nanosilica/CaO composites derived from Ca(OH)2 and nanosilica/Ca(OH)2 dry mixtures subjected in situ to linear and constant rate thermal analysis (CRTA) preheating programs in either air or air/CO2 atmospheres....

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Autores: Valverde, J.M., Sánchez-Jiménez, Pedro E., Perejón, Antonio, Pérez-Maqueda, Luis A.
Tipo de recurso: artículo
Fecha de publicación:2013
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/97332
Acceso en línea:http://hdl.handle.net/10261/97332
Access Level:acceso abierto
Palabra clave:Carbon capture
Ca-looping
CO2 capture
CaO-based sorbents
Thermal pretreatment
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spelling Constant rate thermal analysis for enhancing the long-term CO2 capture of CaO at Ca-looping conditionsValverde, J.M.Sánchez-Jiménez, Pedro E.Perejón, AntonioPérez-Maqueda, Luis A.Carbon captureCa-loopingCO2 captureCaO-based sorbentsThermal pretreatmentExperimental results are reported on the (Ca-looping) multicyclic CO2 capture of CaO and nanosilica/CaO composites derived from Ca(OH)2 and nanosilica/Ca(OH)2 dry mixtures subjected in situ to linear and constant rate thermal analysis (CRTA) preheating programs in either air or air/CO2 atmospheres. By means of CRTA preheating the rates of the reactions taking place during pretreatment are kept at a constant and small value along the entire process. In agreement with a pore skeleton model, previously proposed in the literature for explaining the behavior of natural limestones thermally pretreated, our results suggest that air/CO2-CRTA pretreatment yields a thermally stable hard skeleton of poorly reactive CaO on which a soft skeleton of reactive CaO would be supported. The sorbent subjected to this preheating program exhibits a reactivation in the very first carbonation/calcination cycles, after which CaO conversion decays slowly with the cycle number. In contrast, linearly or air-CRTA preheated sorbents show a significant decrease of CaO conversion within the first cycles. In the latter case, CaO multicyclic conversion fits well to a model where it is assumed that the progressive reduction of surface area as the number of carbonation/calcination cycles is increased obeys to sintering of the preheated sorbent skeleton as it is subjected to repeated calcinations during cycling. In the former case, CaO conversion data conforms to the prediction by a model in which the loss of surface area is mainly due to sintering of a nascent CaO soft skeleton regenerated in the diffusive carbonation phase, which is enhanced by the air/CO2-CRTA pretreatment. As regards the effect of nanosilica, the results indicate that it slows down CaO sintering during pretreatment, which hinders the development of a stable CaO skeleton thus hampering reactivation and stabilization of conversion. On the other hand, as CaO sintering is also lessened during looping calcination, nanosilica is useful to increase the absolute values of CaO conversionPeer reviewedElsevier201420142013info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501http://hdl.handle.net/10261/97332reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttp://dx.doi.org/10.1016/j.apenergy.2013.03.013info:eu-repo/semantics/openAccessoai:digital.csic.es:10261/973322026-05-22T06:33:51Z
dc.title.none.fl_str_mv Constant rate thermal analysis for enhancing the long-term CO2 capture of CaO at Ca-looping conditions
title Constant rate thermal analysis for enhancing the long-term CO2 capture of CaO at Ca-looping conditions
spellingShingle Constant rate thermal analysis for enhancing the long-term CO2 capture of CaO at Ca-looping conditions
Valverde, J.M.
Carbon capture
Ca-looping
CO2 capture
CaO-based sorbents
Thermal pretreatment
title_short Constant rate thermal analysis for enhancing the long-term CO2 capture of CaO at Ca-looping conditions
title_full Constant rate thermal analysis for enhancing the long-term CO2 capture of CaO at Ca-looping conditions
title_fullStr Constant rate thermal analysis for enhancing the long-term CO2 capture of CaO at Ca-looping conditions
title_full_unstemmed Constant rate thermal analysis for enhancing the long-term CO2 capture of CaO at Ca-looping conditions
title_sort Constant rate thermal analysis for enhancing the long-term CO2 capture of CaO at Ca-looping conditions
dc.creator.none.fl_str_mv Valverde, J.M.
Sánchez-Jiménez, Pedro E.
Perejón, Antonio
Pérez-Maqueda, Luis A.
author Valverde, J.M.
author_facet Valverde, J.M.
Sánchez-Jiménez, Pedro E.
Perejón, Antonio
Pérez-Maqueda, Luis A.
author_role author
author2 Sánchez-Jiménez, Pedro E.
Perejón, Antonio
Pérez-Maqueda, Luis A.
author2_role author
author
author
dc.subject.none.fl_str_mv Carbon capture
Ca-looping
CO2 capture
CaO-based sorbents
Thermal pretreatment
topic Carbon capture
Ca-looping
CO2 capture
CaO-based sorbents
Thermal pretreatment
description Experimental results are reported on the (Ca-looping) multicyclic CO2 capture of CaO and nanosilica/CaO composites derived from Ca(OH)2 and nanosilica/Ca(OH)2 dry mixtures subjected in situ to linear and constant rate thermal analysis (CRTA) preheating programs in either air or air/CO2 atmospheres. By means of CRTA preheating the rates of the reactions taking place during pretreatment are kept at a constant and small value along the entire process. In agreement with a pore skeleton model, previously proposed in the literature for explaining the behavior of natural limestones thermally pretreated, our results suggest that air/CO2-CRTA pretreatment yields a thermally stable hard skeleton of poorly reactive CaO on which a soft skeleton of reactive CaO would be supported. The sorbent subjected to this preheating program exhibits a reactivation in the very first carbonation/calcination cycles, after which CaO conversion decays slowly with the cycle number. In contrast, linearly or air-CRTA preheated sorbents show a significant decrease of CaO conversion within the first cycles. In the latter case, CaO multicyclic conversion fits well to a model where it is assumed that the progressive reduction of surface area as the number of carbonation/calcination cycles is increased obeys to sintering of the preheated sorbent skeleton as it is subjected to repeated calcinations during cycling. In the former case, CaO conversion data conforms to the prediction by a model in which the loss of surface area is mainly due to sintering of a nascent CaO soft skeleton regenerated in the diffusive carbonation phase, which is enhanced by the air/CO2-CRTA pretreatment. As regards the effect of nanosilica, the results indicate that it slows down CaO sintering during pretreatment, which hinders the development of a stable CaO skeleton thus hampering reactivation and stabilization of conversion. On the other hand, as CaO sintering is also lessened during looping calcination, nanosilica is useful to increase the absolute values of CaO conversion
publishDate 2013
dc.date.none.fl_str_mv 2013
2014
2014
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
format article
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/97332
url http://hdl.handle.net/10261/97332
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv http://dx.doi.org/10.1016/j.apenergy.2013.03.013
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.812429

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