Monte carlo simulation strategies for predicting CO 2/CH 4 adsorption onto activated carbons from pure gas isotherms

The problem of predicting the adsorptive properties of activated carbon (AC) towards a mixture of gases from the simple knowledge of the adsorption properties of the pure components is addressed, with special reference to the CO2/CH4 mixture. The adsorption process for the pure gases and their mixtures was simulated using the Grand Canonical Monte Carlo (GCMC) method and the calculations were then used to analyze experimental isotherms for the pure gases and for mixtures with different molar fractions in the gaseous phase. It was shown that the pore-size distributions (PSDs) “sensed” by each of the pure probe gases was different one from the other and also from the PSDs “seen” by the mixture. A mixing rule for combining the PSDs corresponding to the pure gases is proposed for obtaining predictions regarding the adsorption of the corresponding mixtures, which are then compared with those arising from the classical IAST approximation. For this purpose, selectivity curves for CO2 relative to CH4 have been calculated and compared with experimental values. It was concluded that, for the adsorbate/adsorbent system under study, the proposed GCMC mixed model was capable of predicting the binary adsorption equilibrium, and especially the selectivity, more accurately than the IAST.Fil: de Oliveira, José C. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Física Aplicada; Argentina. Universidad Nacional de San Luis; ArgentinaFil: Rios, Rafael B.. Universidade Federal do Ceará; BrasilFil: López, Raúl Horacio. Universidad Nacional de San Luis; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Física Aplicada; ArgentinaFil: Peixoto, Hugo R.. Universidade Federal do Ceará; BrasilFil: Cornette, Valeria Cecilia. Universidad Nacional de San Luis; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Física Aplicada; ArgentinaFil: Torres, A. Eurico B.. Universidade Federal do Ceará; BrasilFil: Calvalcante Jr., Célio L.. Universidade Federal do Ceará; BrasilFil: Zgrablich, Jorge Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Física Aplicada; Argentina. Universidad Nacional de San Luis; Argentin

Evaluation of carbon dioxide-nitrogen separation through fixed bed measurements and simulations

The increasing emissions of carbon dioxide have been pointed out as a major cause for global warming, as a consequence of the intensification of the greenhouse effect in our planet. Therefore, technologies of carbon capture and storage (CCS) have been developed with the purpose of reducing the concentration of CO2 in gas emissions (flue gas). Thus, adsorption-based methods are a very promising cost-efficient technology, particularly in processes such as pressure swing adsorption (PSA). The knowledge of adsorption dynamics in fixed bed is of essential importance for the design of industrial scale units. The objective of the present work is to evaluate the suitability of activated carbons (AC) and metal organic-frameworks (MOF) samples for CO2 capture by measuring multicomponent breakthrough curves. CO2-N-2 systems have been studied for this purpose and a model based on the linear driving force (LDF) approximation for the mass transfer was developed to simulate breakthrough curves under the same experimental conditions. The selectivity of the samples for the adsorption of CO2 over N-2 was also evaluated and compared. Results suggest that the AC C141 has a great potential for the separation of CO2 from N-2 at 348 K, since it presents a comparable selectivity (6.2) to the MOF sample Cu-BTC (8.0), and it is much more stable to contaminants present in flue gas scenarios, particularly water vapor. This may be explained by its narrow microporosity as compared to the other activated carbon samples. Despite the high microprosity, sample AC C141 also showed the fastest intraparticle kinetics (D-c/r(c)(2) approximate to 6.0 x 10(-2) s(-1)), which suits it for fast adsorption/desorption cycles as in PSA plants

CO2 adsorption capacity of zeolites synthesized from coal fly ashes

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Parametric Analysis of a Moving Bed Temperature Swing Adsorption (MBTSA) Process for Postcombustion CO 2 Capture

International audienc

Assessment of the potential use of zeolites synthesized from power plant fly ash to capture CO2 under post-combustion scenario

International audienc