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Title: Carbon dioxide adsorption in Brazilian coals

Abstract

Carbon dioxide (CO{sub 2}) is one of the most important greenhouse gases. In the period between 1980 and 1998, CO{sub 2} emissions increased more than 21% and projections suggest that the emissions will continue to increase globally by 2.2% between 2000 and 2020 and 3.3% in the developed countries. The sequestration of CO{sub 2} in deep unminable coal beds is one of the more promising of several methods of geological sequestration that are currently being investigated. CO{sub 2} can adsorb onto coal, and there are several studies demonstrating that CO{sub 2} dissolves in coals and swells them. At very low pressures (P {lt} 1 bar), CO{sub 2} dissolution does not seem to be a problem; however, high pressures are necessary for CO{sub 2} sequestration (P {gt} 50 bar). In this study, we evaluated the kinetics and equilibrium of sorption of CO{sub 2} on Brazilian coals at low pressures. The adsorption equilibrium isotherm at room temperature (30{sup o}C) was measured through the static method. The results showed that the Freundlich model or the Langmuir model is suitable to describe the equilibrium experimental results. The CO{sub 2} adsorption capacity of Brazilian coals are in the range of 0.089-0.186 mmol CO{sub 2}/g, whichmore » are typical values for coals with high ash content. The dynamics of adsorption in a fixed-bed column that contains granular coal (particle sizes of 0.8, 2.4, and 4.8 mm) showed that the adsorption rate is fast and a mathematical model was developed to describe the CO{sub 2} dynamics of the adsorption in a fixed-bed column. The linear driving force (LDF) was used to describe the rate of adsorption and the mass-transfer constants of the LDF model (K{sub s}) are in the range of 1.0-2.0 min{sup -1}. 29 refs., 5 figs., 3 tabs.« less

Authors:
; ; ; ;  [1]
  1. Universidade Federal de Santa Catarina, Florianopolis SC (Brazil). Departamento de Engenharia Quimica e Engenharia de Alimentos
Publication Date:
OSTI Identifier:
20862166
Resource Type:
Journal Article
Resource Relation:
Journal Name: Energy and Fuels; Journal Volume: 21; Journal Issue: 1; Other Information: regina@enq.ufsc.br
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; CARBON DIOXIDE; ADSORPTION; COAL; ASH CONTENT; CARBON SEQUESTRATION; COAL SEAMS; UNDERGROUND STORAGE; DISSOLUTION; ADSORPTION ISOTHERMS; BRAZIL; MATHEMATICAL MODELS

Citation Formats

Jose Luciano Soares, Andre L.B. Oberziner, Humberto J. Jose, Alirio E. Rodrigues, and Regina F.P.M. Moreira. Carbon dioxide adsorption in Brazilian coals. United States: N. p., 2007. Web. doi:10.1021/ef060149h.
Jose Luciano Soares, Andre L.B. Oberziner, Humberto J. Jose, Alirio E. Rodrigues, & Regina F.P.M. Moreira. Carbon dioxide adsorption in Brazilian coals. United States. doi:10.1021/ef060149h.
Jose Luciano Soares, Andre L.B. Oberziner, Humberto J. Jose, Alirio E. Rodrigues, and Regina F.P.M. Moreira. Mon . "Carbon dioxide adsorption in Brazilian coals". United States. doi:10.1021/ef060149h.
@article{osti_20862166,
title = {Carbon dioxide adsorption in Brazilian coals},
author = {Jose Luciano Soares and Andre L.B. Oberziner and Humberto J. Jose and Alirio E. Rodrigues and Regina F.P.M. Moreira},
abstractNote = {Carbon dioxide (CO{sub 2}) is one of the most important greenhouse gases. In the period between 1980 and 1998, CO{sub 2} emissions increased more than 21% and projections suggest that the emissions will continue to increase globally by 2.2% between 2000 and 2020 and 3.3% in the developed countries. The sequestration of CO{sub 2} in deep unminable coal beds is one of the more promising of several methods of geological sequestration that are currently being investigated. CO{sub 2} can adsorb onto coal, and there are several studies demonstrating that CO{sub 2} dissolves in coals and swells them. At very low pressures (P {lt} 1 bar), CO{sub 2} dissolution does not seem to be a problem; however, high pressures are necessary for CO{sub 2} sequestration (P {gt} 50 bar). In this study, we evaluated the kinetics and equilibrium of sorption of CO{sub 2} on Brazilian coals at low pressures. The adsorption equilibrium isotherm at room temperature (30{sup o}C) was measured through the static method. The results showed that the Freundlich model or the Langmuir model is suitable to describe the equilibrium experimental results. The CO{sub 2} adsorption capacity of Brazilian coals are in the range of 0.089-0.186 mmol CO{sub 2}/g, which are typical values for coals with high ash content. The dynamics of adsorption in a fixed-bed column that contains granular coal (particle sizes of 0.8, 2.4, and 4.8 mm) showed that the adsorption rate is fast and a mathematical model was developed to describe the CO{sub 2} dynamics of the adsorption in a fixed-bed column. The linear driving force (LDF) was used to describe the rate of adsorption and the mass-transfer constants of the LDF model (K{sub s}) are in the range of 1.0-2.0 min{sup -1}. 29 refs., 5 figs., 3 tabs.},
doi = {10.1021/ef060149h},
journal = {Energy and Fuels},
number = 1,
volume = 21,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • Carbon dioxide (CO{sub 2}) adsorption isotherms were measured on five different rank coals at 328.2 K and pressures up to 13.8 MPa using a volumetric method. Specifically, Beulah Zap, Illinois no.6, Pocahontas No.3, Upper Freeport, and Wyodak coals from the Argonne premium coal sample program were used for these isotherm measurements. These newly acquired data are compared to our previous data on dry coals. As expected, the adsorption on the wet coals is lower than that on the dry coals. At 7 MPa, Pocahontas, Upper Freeport, Illinois no. 6, Wyodak, and Beulah Zap coals exhibited, respectively, about 19, 17, 48,more » 76, and 79% reduction in the amount adsorbed on the wet coal when compared to the adsorption on the dry coal. These reductions in CO{sub 2} adsorption correlate positively with the amount of moisture present on the coal. The isotherms on wet coals were measured at their equilibrium moisture content. The adsorption isotherm for each of the wet coals exhibited a Gibbs adsorption maximum between 8 and 12 MPa and occurred at a higher pressure than that of the dry coal. The simplified local-density/Peng-Robinson model was used to correlate the adsorption data. The model was found capable of representing precisely the CO{sub 2} adsorption on both dry and wet coals. Specifically, the overall weighed average absolute deviation (WAAD) for the five dry and wet coals was 0.99 and 0.42, respectively. Nevertheless, more rigorous accounting for the water interactions with the coal matrix and the competitive adsorption between water and CO{sub 2} would provide an even more realistic description of coal-bed gas adsorption phenomenon on wet coals. 43 refs., 10 figs., 9 tabs.« less
  • With the growing concern about global warming placing greater demands on improving energy efficiency and reducing CO{sub 2} emissions, the need for improving the energy intensive, separation processes involving CO{sub 2} is well recognized. The US Department of Energy estimates that the separation of CO{sub 2} represents 75% of the cost associated with its separation, storage, transport, and sequestration operations. Hence, energy efficient, CO{sub 2} separation technologies with improved economics are needed for industrial processing and for future options to capture and concentrate CO{sub 2} for reuse or sequestration. The overall goal of this review is to foster the developmentmore » of new adsorption and membrane technologies to improve manufacturing efficiency and reduce CO{sub 2} emissions. This study focuses on the power, petrochemical, and other CO{sub 2} emitting industries, and provides a detailed review of the current commercial CO{sub 2} separation technologies, i.e., absorption, adsorption, membrane, and cryogenic, an overview of the emerging adsorption and membrane technologies for CO{sub 2} separation, and both near and long term recommendations for future research on adsorption and membrane technologies. Flow sheets of the principal CO{sub 2} producing processes are provided for guidance and new conceptual flow sheets with ideas on the placement of CO{sub 2} separations technologies have also been devised.« less
  • The authors study the changes in adsorption heat of CO/sub 2/ upon the substitution of Na/sup +/ by Ca/sup 2 +/ in faujasite, chabazite, mordenite, erionite, and L zeolites. The substitution of sodium ions by calcuium ions in the crystal lattices of faujasites, chabazites, mordenites, and erionites leads to an increase in the heats of adsorption of carbon dioxide at relatively low occupancies. The extent of the occupancy ranges, for which enhanced heats of adsorption are found, correlate in general with the amounts of calcium cations which may directly interact with the adsorbed molecules.
  • Isotherms of adsorption from a mixture of carbon dioxide and xenon on aluminum oxide at 173/sup 0/K, obtained in a previous experiment, are discussed. Adsorption energy distributions are calculated. The heterogeneous surface of the adsorbent is taken into consideration in the interpretation of the data.