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Carbonation and active-component-distribution behaviors of several potassium-based sorbents / Chuanwen Zhao in Industrial & engineering chemistry research, Vol. 50 N° 8 (Avril 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4464–4470 Titre : Carbonation and active-component-distribution behaviors of several potassium-based sorbents Type de document : texte imprimé Auteurs : Chuanwen Zhao, Auteur ; Xiaoping Chen, Auteur ; Changsui Zhao, Auteur Année de publication : 2011 Article en page(s) : pp. 4464–4470 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbonation  Potassium  Sorbents Résumé : To investigate active-component-distribution and carbonation behaviors, potassium-based sorbents were prepared by impregnation of K2CO3, K2CO3·1.5H2O, and KHCO3 on supports such as activated carbon (AC) and Al2O3. The CO2 capture capacity is significantly increased for K2CO3 and K2CO3 dehydrated from K2CO3·1.5H2O after they have been loaded on AC and Al2O3. For the sorbents with AC as their support, the active components keep their original phase in the impregnation process. Under an atmosphere of CO2 and H2O, the hydration reaction occurs first, and then KHCO3 is produced rapidly. The active components are held in macropore spaces without blocking micropores, and the rest is nonuniformly distributed on the surface of AC in the form of large aggregates. For the sorbents with Al2O3 as their support, all of the active components change into K2CO3 during the impregnation process. Under the same reaction atmosphere, K2CO3·1.5H2O is not produced. H2O is adsorbed at first, and then CO2 reacts with the adsorbed H2O and K2CO3 to produce KHCO3. Most of the active components are distributed in the mesopores and macropores of the support, and the rest is uniformly distributed on the surface of Al2O3 in the form of many small ag gregates. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200153c [article] Carbonation and active-component-distribution behaviors of several potassium-based sorbents [texte imprimé] / Chuanwen Zhao, Auteur ; Xiaoping Chen, Auteur ; Changsui Zhao, Auteur . - 2011 . - pp. 4464–4470. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4464–4470 Mots-clés : Carbonation  Potassium  Sorbents Résumé : To investigate active-component-distribution and carbonation behaviors, potassium-based sorbents were prepared by impregnation of K2CO3, K2CO3·1.5H2O, and KHCO3 on supports such as activated carbon (AC) and Al2O3. The CO2 capture capacity is significantly increased for K2CO3 and K2CO3 dehydrated from K2CO3·1.5H2O after they have been loaded on AC and Al2O3. For the sorbents with AC as their support, the active components keep their original phase in the impregnation process. Under an atmosphere of CO2 and H2O, the hydration reaction occurs first, and then KHCO3 is produced rapidly. The active components are held in macropore spaces without blocking micropores, and the rest is nonuniformly distributed on the surface of AC in the form of large aggregates. For the sorbents with Al2O3 as their support, all of the active components change into K2CO3 during the impregnation process. Under the same reaction atmosphere, K2CO3·1.5H2O is not produced. H2O is adsorbed at first, and then CO2 reacts with the adsorbed H2O and K2CO3 to produce KHCO3. Most of the active components are distributed in the mesopores and macropores of the support, and the rest is uniformly distributed on the surface of Al2O3 in the form of many small ag gregates. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200153c

Carbonation behavior and the reaction kinetic of a new dry potassium-based sorbent for CO2 capture / Chuanwen Zhao in Industrial & engineering chemistry research, Vol. 51 N° 44 (Novembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 44 (Novembre 2012) . - pp. 14361-14366 Titre : Carbonation behavior and the reaction kinetic of a new dry potassium-based sorbent for CO2 capture Type de document : texte imprimé Auteurs : Chuanwen Zhao, Auteur ; Xiaoping Chen, Auteur ; Changsui Zhao, Auteur Année de publication : 2013 Article en page(s) : pp. 14361-14366 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Carbon  dioxide  Kinetics  Carbonation Résumé : The carbonation behaviors of K2CO3 generated by calcination of KHCO3 were investigated with a pressurized thermo gravimetric apparatus, and the shrinking-core model in the noncatalytic heterogeneous reaction systems was used to explain the kinetics of the reaction between K2CO3, CO2 and H2O using analysis of the experimental breakthrough data. The carbonation reaction process can be divided into two stage-controlled regions, one is the surface chemical reaction-controlled region at the initial stage and another is the internal diffusion-controlled region at the last stage. The total amount of carbonation conversion is mainly dependent on the first stage. The reaction rate of this stage decreases as the reaction temperature increases. It increases in the same temperature when the CO2 and H2O concentrations increase. The total carbonation conversion decreases as the pressure increases. On the basis of the Arrhenius equation, the apparent activation energy and pre-exponential factor for these two stages are calculated, when the temperature is in the range of 55―80 °C and the pressure is 0.1 MPa. They are 33.4 kJ/mol and 3.56 cm/min for the surface chemical reaction-controlled region and 99.1 kJ/mol and 4.01 X 10―22 cm2/min for the internal diffusion-controlled region. This paper provides theoretical basis for the further study on the capture of CO2 from flue gas using dry potassium-based sorbents. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26620349 [article] Carbonation behavior and the reaction kinetic of a new dry potassium-based sorbent for CO2 capture [texte imprimé] / Chuanwen Zhao, Auteur ; Xiaoping Chen, Auteur ; Changsui Zhao, Auteur . - 2013 . - pp. 14361-14366. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 44 (Novembre 2012) . - pp. 14361-14366 Mots-clés : Carbon  dioxide  Kinetics  Carbonation Résumé : The carbonation behaviors of K2CO3 generated by calcination of KHCO3 were investigated with a pressurized thermo gravimetric apparatus, and the shrinking-core model in the noncatalytic heterogeneous reaction systems was used to explain the kinetics of the reaction between K2CO3, CO2 and H2O using analysis of the experimental breakthrough data. The carbonation reaction process can be divided into two stage-controlled regions, one is the surface chemical reaction-controlled region at the initial stage and another is the internal diffusion-controlled region at the last stage. The total amount of carbonation conversion is mainly dependent on the first stage. The reaction rate of this stage decreases as the reaction temperature increases. It increases in the same temperature when the CO2 and H2O concentrations increase. The total carbonation conversion decreases as the pressure increases. On the basis of the Arrhenius equation, the apparent activation energy and pre-exponential factor for these two stages are calculated, when the temperature is in the range of 55―80 °C and the pressure is 0.1 MPa. They are 33.4 kJ/mol and 3.56 cm/min for the surface chemical reaction-controlled region and 99.1 kJ/mol and 4.01 X 10―22 cm2/min for the internal diffusion-controlled region. This paper provides theoretical basis for the further study on the capture of CO2 from flue gas using dry potassium-based sorbents. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26620349

Carbonation behavior of K2CO3 with different microstructure used as an active component of dry sorbents for CO2 capture / Chuanwen Zhao in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12212-12216 Titre : Carbonation behavior of K2CO3 with different microstructure used as an active component of dry sorbents for CO2 capture Type de document : texte imprimé Auteurs : Chuanwen Zhao, Auteur ; Xiaoping Chen, Auteur ; Changsui Zhao, Auteur Année de publication : 2011 Article en page(s) : pp. 12212-12216 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbon  dioxide  Microstructure  Carbonation Résumé : To choose the proper active component for potassium-based sorbents to capture CO2, the carbonation behavior of some potassium carbonate from different sources was investigated with thermogravimetric analysis (TGA) and a fixed-bed reactor. The results show that the carbonation reaction process and the reaction rate of the samples are different, although their crystal structures and elemental compositions are the same. K2CO3 calcined from KHCO3 shows excellent carbonation capacity through producing the active species of K4H2(CO3)3·1.5H2O The dimensionless weight increased to 1.36 in 27.7 min in TGA, corresponding to 80.2% conversion of the K2CO3 to KHCO3. The amount of CO2 capture reached 6.74 mol/(kg sorbent) within 23.3 min, corresponding to 93.0% conversion of the K2CO3 to KHCO3. The reason is that the particle morphologies of those sorbents are different: the surface area and pore volume of K2CO3 calcined from KHCO3 are the highest, and the porc distribution range is wider than that of other samples. Therefore, it is better to load potassium carbonate one? a support with a large surface area and pore volume, to improve the CO2 capture capacity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463385 [article] Carbonation behavior of K2CO3 with different microstructure used as an active component of dry sorbents for CO2 capture [texte imprimé] / Chuanwen Zhao, Auteur ; Xiaoping Chen, Auteur ; Changsui Zhao, Auteur . - 2011 . - pp. 12212-12216. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12212-12216 Mots-clés : Carbon  dioxide  Microstructure  Carbonation Résumé : To choose the proper active component for potassium-based sorbents to capture CO2, the carbonation behavior of some potassium carbonate from different sources was investigated with thermogravimetric analysis (TGA) and a fixed-bed reactor. The results show that the carbonation reaction process and the reaction rate of the samples are different, although their crystal structures and elemental compositions are the same. K2CO3 calcined from KHCO3 shows excellent carbonation capacity through producing the active species of K4H2(CO3)3·1.5H2O The dimensionless weight increased to 1.36 in 27.7 min in TGA, corresponding to 80.2% conversion of the K2CO3 to KHCO3. The amount of CO2 capture reached 6.74 mol/(kg sorbent) within 23.3 min, corresponding to 93.0% conversion of the K2CO3 to KHCO3. The reason is that the particle morphologies of those sorbents are different: the surface area and pore volume of K2CO3 calcined from KHCO3 are the highest, and the porc distribution range is wider than that of other samples. Therefore, it is better to load potassium carbonate one? a support with a large surface area and pore volume, to improve the CO2 capture capacity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463385