Cyclic Fixed-Bed Operations over K2CO3-on-Carbon for the Recovery of Carbon Dioxide under Moist Conditions

Hirano, Shin‐ichi; Shigemoto, Naoya; Yamada, Shinichi; Hayashi, Hiromu

doi:10.1246/bcsj.68.1030

Cited by 61 publications

(65 citation statements)

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“…Alkali metal carbonates such as Na 2 CO 3 and K 2 CO 3 react with CO 2 and H 2 O and transform to alkali metal hydrogen carbonates after CO 2 absorption by the following reaction, M 2 CO 3 þ CO 2 þ H 2 O 2MHCO 3 ðM ¼ Na; KÞ [18][19][20][21][22][23][24][25][26][27][28][29]. Water vapor is always necessary in forming potassium hydrogen carbonate in all reactions as shown in the absorption mechanism, unlike alkaline earth metalbased sorbents, while moisture contained in the flue gases as high as 8-17 vol.% negatively affected the adsorption capacity of molecular sieves [9].…”

Section: Introductionmentioning

confidence: 99%

“…Alkali metal-based sorbents were employed in CO 2 absorption at low temperatures (50-70°C) with thermal regeneration easily occurring at low temperatures below 200°C. Hirano et al have proposed a modified chemical-absorption method capable of cyclic fixed-bed operations for the recovery of carbon dioxide from flue gases over K 2 CO 3 -on-carbon [19]. Deliquescent potassium carbonate was supported on activated carbon to adapt for cyclic fixed-bed operations and showed breakthrough curves with sharp frontal edges [19,20].…”

Section: Introductionmentioning

confidence: 99%

“…Hirano et al have proposed a modified chemical-absorption method capable of cyclic fixed-bed operations for the recovery of carbon dioxide from flue gases over K 2 CO 3 -on-carbon [19]. Deliquescent potassium carbonate was supported on activated carbon to adapt for cyclic fixed-bed operations and showed breakthrough curves with sharp frontal edges [19,20]. The sorption of CO 2 on the K 2 CO 3 -Al 2 O 3 composite sorbent, in the presence of water vapor, was studied by in situ IR spectroscopy and X-ray diffraction analysis [22].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dry Potassium-Based Sorbents for CO2 Capture

2007

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Dry potassium-based sorbents were prepared by impregnation with potassium carbonate on supports such as activated carbon (AC), TiO 2 , Al 2 O 3 , MgO, CaO, SiO 2 and various zeolites. The CO 2 capture capacity and regeneration property of various sorbents were measured in the presence of H 2 O in a fixed bed reactor, during multiple cycles at various temperature conditions (CO 2 absorption at 50-100°C and regeneration at 130-400°C). The KAlI30, KCaI30, and KMgI30 sorbents formed new structures such as KAl(CO 3 ) 2 (OH) 2 , K 2 Ca(CO 3 ) 2 , K 2 Mg(CO 3 ) 2 , and K 2 Mg(CO 3 ) 2 Á4(H 2 O), which did not completely convert to the original K 2 CO 3 phase at temperatures below 200°C, during the CO 2 absorption process in the presence of 9 vol.% H 2 O. In the case of KACI30, KTiI30, and KZrI30, only a KHCO 3 crystal structure was formed during CO 2 absorption. The formation of active species, K 2 CO 3 Á1.5H 2 O, by the pretreatment with water vapor and the formation of the KHCO 3 crystal structure after CO 2 absorption are important factors for absorption and regeneration, respectively, even at low temperatures (130-150°C). In particular, the KTiI30 sorbent showed excellent characteristics with respect to CO 2 absorption and regeneration in that it satisfies the requirements of a large amount of CO 2 absorption (87 mg CO 2 /g sorbent) without the pretreatment with water vapor, unlike KACI30, and a fast and complete regeneration at a low temperature condition (1 atm, 150°C). In addition, the higher total CO 2 capture capacity of KMgI30 (178.6 mg CO 2 /g sorbent) than that of the theoretical value (95 mg CO 2 /g sorbent) was explained through the contribution of the absorption ability of MgO support. In this review, we introduce the CO 2 capture capacities and regeneration properties of several potassium-based sorbents, the changes in the physical properties of the sorbents before/after CO 2 absorption, and the role of water vapor and its effects on CO 2 absorption.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dry Potassium-Based Sorbents for CO2 Capture

2007

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“…However, when CO 2 reacts with Na 2 CO 3 , the rate of global carbonation is rather slow (Zhao et al 2009). The CO 2 adsorption and regeneration using potassium-based sorbents with several supports such as activated carbon (Hirano et al 1995;Hayashi et al 1998;Shigemoto et al 2006), TiO 2 , SiO 2 , MgO, ZrO 2 , CaO and Al 2 O 3 were also reported in previous studies (Okunev et al 2000(Okunev et al , 2003Lee et al 2004;Liang et al 2004). Al 2 O 3 is one of the ideal materials used as a sorbent support.…”

Section: Introductionmentioning

confidence: 54%

Preparation of a Low-Cost K₂CO₃/Al₂O₃ Sorbent for CO₂ Capture at Flue-Gas Operating Conditions

Esmaili

Ehsani

2013

Adsorption Science & Technology

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ABSTRACT:In this study, the efficiency of a low-cost K 2 CO 3 /Al 2 O 3 sorbent as a CO 2 capture support was investigated. The sorbent was prepared by impregnating K 2 CO 3 on industrial-grade Al 2 O 3 . The CO 2 capture capacity of the sorbent was calculated from the breakthrough curve of the CO 2 adsorption inside a fixed-bed reactor, in the presence of H 2 O and at an adsorption temperature of 60 °C. An adsorption capacity of 75.4 mg CO 2 /g of sorbent was obtained. The stability of capture capacity of the sorbent was higher than that of the reference sorbent. The changes in the pore volume and surface area were 0.020 cm 3 /g and 5.5 m 2 /g, respectively, after five cycles of adsorption and regeneration. However, there were minor changes in the pore-size distribution and surface area of the sorbent after five cycles. This sorbent can be considered to be used in large-scale applications.

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“…Hirano et al 38 and Hayashi et al 39 reported that the formation of active species, K 2 CO 3 ·1.5H 2 O, plays an important role in the CO 2 capture capacity and that a vapor pretreatment process substantially improved CO 2 capture capacity. 40 The experimental results showed that the CO 2 capture capacity could be enhanced due to the conversion of the K 2 CO 3 phase to the K 2 CO 3 ·1.5H 2 O phase through the K 4 H 2 (CO 3 ) 3 ·1.5H 2 O phase during pretreatment with sufficient water vapor.…”

Section: Application To Dehydrated and Anhydrous Potassium Carbonatesmentioning

confidence: 99%

Theoretical calculating the thermodynamic properties of solid sorbents for CO{sub 2} capture applications

Duan¹

2012

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Since current technologies for capturing CO 2 to fight global climate change are still too energy intensive, there is a critical need for development of new materials that can capture CO 2 reversibly with acceptable energy costs. Accordingly, solid sorbents have been proposed to be used for CO 2 capture applications through a reversible chemical transformation. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO 2 sorbent candidates from the vast array of possible solid materials has been proposed and validated. The calculated thermodynamic properties of different classes of solid materials versus temperature and pressure changes were further used to evaluate the equilibrium properties for the CO 2 adsorption/desorption cycles. According to the requirements imposed by the pre-and post-combustion technologies and based on our calculated thermodynamic properties for the CO 2 capture reactions by the solids of interest, we were able to screen only those solid materials for which lower capture energy costs are expected at the desired pressure and temperature conditions. Only those selected CO 2 sorbent candidates were further considered for experimental validations. The ab initio thermodynamic technique has the advantage of identifying thermodynamic properties of CO 2 capture reactions without any experimental input beyond crystallographic structural information of the solid phases involved. Such methodology not only can be used to search for good candidates from existing database of solid materials, but also can provide some guidelines for synthesis new materials. In this presentation, we first introduce our screening methodology and the results on a testing set of solids with known thermodynamic properties to validate our methodology. Then, by applying our computational method to several different kinds of solid systems, we demonstrate that our methodology can predict the useful information to help developing CO 2 capture Technologies.

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Cyclic Fixed-Bed Operations over K2CO3-on-Carbon for the Recovery of Carbon Dioxide under Moist Conditions

Cited by 61 publications

References 1 publication

Dry Potassium-Based Sorbents for CO2 Capture

Dry Potassium-Based Sorbents for CO2 Capture

Preparation of a Low-Cost K₂CO₃/Al₂O₃ Sorbent for CO₂ Capture at Flue-Gas Operating Conditions

Theoretical calculating the thermodynamic properties of solid sorbents for CO{sub 2} capture applications

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Cyclic Fixed-Bed Operations over K2CO3-on-Carbon for the Recovery of Carbon Dioxide under Moist Conditions

Cited by 61 publications

References 1 publication

Dry Potassium-Based Sorbents for CO2 Capture

Dry Potassium-Based Sorbents for CO2 Capture

Preparation of a Low-Cost K2CO3/Al2O3 Sorbent for CO2 Capture at Flue-Gas Operating Conditions

Theoretical calculating the thermodynamic properties of solid sorbents for CO{sub 2} capture applications

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Preparation of a Low-Cost K₂CO₃/Al₂O₃ Sorbent for CO₂ Capture at Flue-Gas Operating Conditions