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Precipitation of piperazine in aqueous piperazine solutions with and without CO2 loadings / Xiaoguang Ma in Industrial & engineering chemistry research, Vol. 51 N° 37 (Septembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 37 (Septembre 2012) . - pp. 12126–12134 Titre : Precipitation of piperazine in aqueous piperazine solutions with and without CO2 loadings Type de document : texte imprimé Auteurs : Xiaoguang Ma, Auteur ; Inna Kim, Auteur ; Ralf Beck, Auteur Année de publication : 2012 Article en page(s) : pp. 12126–12134 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Piperazine  Crystallization Résumé : The crystallization of piperazine in water as well as in systems loaded with CO2 has been studied for piperazine concentrations of 30–70 wt %, representing conditions relevant for CO2 capture. The use of a LabMax reactor system equipped with probes for in situ focused beam reflectance measurement (FBRM) and particle vision measurement (PVM) made it possible to determine solid–liquid transitions, crystal habit, and chord length distributions in these highly concentrated systems without disturbing the solid–liquid–gas equilibrium during crystallization. As shown by powder X-ray diffraction analysis, three phases including piperazine hemihydrate, piperazine hexahydrate, and anhydrous crystals were precipitated from the aqueous piperazine solutions at different concentrations and temperatures, as also supported by findings from FBRM and PVM. It was found that the metastable zone widths of the piperazine–H2O system were substantial even at the lower cooling rates, which could allow for a higher tolerance with respect to cooling prior to a new carbon dioxide absorption cycle. However, the eutectic composition exhibits a smaller metastable zone width than the other concentrations, which is believed to be caused by the precursor needle-shaped crystals, assisting the precipitation of the final product. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301101q [article] Precipitation of piperazine in aqueous piperazine solutions with and without CO2 loadings [texte imprimé] / Xiaoguang Ma, Auteur ; Inna Kim, Auteur ; Ralf Beck, Auteur . - 2012 . - pp. 12126–12134. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 37 (Septembre 2012) . - pp. 12126–12134 Mots-clés : Piperazine  Crystallization Résumé : The crystallization of piperazine in water as well as in systems loaded with CO2 has been studied for piperazine concentrations of 30–70 wt %, representing conditions relevant for CO2 capture. The use of a LabMax reactor system equipped with probes for in situ focused beam reflectance measurement (FBRM) and particle vision measurement (PVM) made it possible to determine solid–liquid transitions, crystal habit, and chord length distributions in these highly concentrated systems without disturbing the solid–liquid–gas equilibrium during crystallization. As shown by powder X-ray diffraction analysis, three phases including piperazine hemihydrate, piperazine hexahydrate, and anhydrous crystals were precipitated from the aqueous piperazine solutions at different concentrations and temperatures, as also supported by findings from FBRM and PVM. It was found that the metastable zone widths of the piperazine–H2O system were substantial even at the lower cooling rates, which could allow for a higher tolerance with respect to cooling prior to a new carbon dioxide absorption cycle. However, the eutectic composition exhibits a smaller metastable zone width than the other concentrations, which is believed to be caused by the precursor needle-shaped crystals, assisting the precipitation of the final product. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301101q