Revisiting film theory to consider approaches for enhanced solvent-process design for carbon capture

Wilcox, Jennifer; Rochana, Panithita; Kirchofer, Abby; Glatz, Guenther; He, Jiajun

doi:10.1039/c4ee00001c

Cited by 35 publications

(21 citation statements)

References 49 publications

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“…tanh(Ha) ∼ = 1) then the enhancement factor is approximately equal to Ha. The reaction behavior is thus similar to a first order behavior hence fast pseudo-first order (Wilcox et al, 2014). A further MEA concentration increase would give an instantaneous behavior.…”

Section: Chemical System Descriptionmentioning

confidence: 81%

Micro-scale CFD modeling of reactive mass transfer in falling liquid films within structured packing materials

Sebastia‐Saez

Ranganathan

et al. 2015

International Journal of Greenhouse Gas Control

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Post-combustion carbon capture in structured packing columns is considered as a promising technology to reduce greenhouse gas (GHG) emissions because of its maturity and the possibility of being retrofitted to existing power plants. CFD plays an important role in the optimization of this technology. However, due to the current computational capacity limitations, the simulations need to be divided into three scales (i.e. micro-, meso- and macro-scale) depending on the flow characteristics to be analyzed. This study presents a 3D micro-scale approach to describe the hydrodynamics and reactive mass transfer of the CO2-MEA chemical system within structured packing materials. Higbie's penetration theory is used to describe the mass transfer characteristics whereas enhancement factors are implemented to represent the gain in the absorption rate attributable to the chemical reaction. The results show a detrimental effect of the liquid load on the absorption rate via a decrease in the enhancement factor. The evolution of the wetted area for MEA solutions is compared to the case of pure water highlighting the differences in the transient behavior. The CO2 concentration profiles are examined showing the capability of the model to reproduce the depletion of the solute within the bulk liquid ascribed to the high value of the Hatta number. Also, several approaches on the reaction mechanism such as reversibility and instantaneous behavior are assessed. The results from micro-scale are to be used in meso-scale analysis in future studies to optimize the reactive absorption characteristics of structured packing materials

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Section: Chemical System Descriptionmentioning

confidence: 81%

Micro-scale CFD modeling of reactive mass transfer in falling liquid films within structured packing materials

Sebastia‐Saez

Ranganathan

et al. 2015

International Journal of Greenhouse Gas Control

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“…[23] It is plausible that organic solvents have ad iffusion barrier at the interface where CO 2 -rich ions would congregatea tt he interface because the solventis1 00 %c oncentrated, and all CO 2 BOL molecules at the interface would be carboxylatedb ecause they are closest in proximity to CO 2 at the gas/liquid interface. The Wilcox group at Stanford has recently proposed differences in organic versus aqueous films, such as molecular ordering and whether or not organicsh ave reactive or inert interfaces.…”

Section: Rationalizing the Inverse Temperature Dependencementioning

confidence: 99%

“…The Wilcox group at Stanford has recently proposed differences in organic versus aqueous films, such as molecular ordering and whether or not organicsh ave reactive or inert interfaces. [23] It is plausible that organic solvents have ad iffusion barrier at the interface where CO 2 -rich ions would congregatea tt he interface because the solventis1 00 %c oncentrated, and all CO 2 BOL molecules at the interface would be carboxylatedb ecause they are closest in proximity to CO 2 at the gas/liquid interface. This is in direct contrastt ot heories of surface replenishment of aqueous films.…”

Section: Data Setmentioning

confidence: 99%

Measuring the Absorption Rate of CO₂ in Nonaqueous CO₂‐Binding Organic Liquid Solvents with a Wetted‐Wall Apparatus

et al. 2015

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The kinetics of the absorption of CO2 into two nonaqueous CO2-binding organic liquid (CO2 BOL) solvents were measured at T=35, 45, and 55 °C with a wetted-wall column. Selected CO2 loadings were run with a so-called "first-generation" CO2 BOL, comprising an independent base and alcohol, and a "second-generation" CO2 BOL, in which the base and alcohol were conjoined. Liquid-film mass-transfer coefficient (k'g ) values for both solvents were measured to be comparable to values for monoethanolamine and piperazine aqueous solvents under a comparable driving force, in spite of far higher solution viscosities. An inverse temperature dependence of the k'g value was also observed, which suggests that the physical solubility of CO2 in organic liquids may be making CO2 mass transfer faster than expected. Aspen Plus software was used to model the kinetic data and compare the CO2 absorption behavior of nonaqueous solvents with that of aqueous solvent platforms. This work continues our development of the CO2 BOL solvents. Previous work established the thermodynamic properties related to CO2 capture. The present paper quantitatively studies the kinetics of CO2 capture and develops a rate-based model.

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“…The mass transfer has been modelled following the two-lm theory 66 as reviewed for carbon capture by Wilcox et al 67 Nonreactive thermodynamic equilibrium is assumed to be attained at the gas-liquid interface. If absorption occurs at low pressure, it can be assumed that it obeys Henry's law, so the molar fraction of the solute at the liquid interface with the physical solvent (x 0,I i ), assuming ideal gas and liquid, would be calculated as:…”

Section: Absorption and Desorptionmentioning

confidence: 99%

“…Having said that, the surface tension is expected to play a more important role in the case of non-reactive solvents. 67 In conclusion, viscosity and heat capacity are the primary thermophysical properties that together with the equilibrium constant impact the mass transfer and the energy transfer. The feasible parameter space which corresponds to a reduction in the cost of carbon capture with respect to the benchmark is identied in Fig.…”

Section: Evaluation Of the Thermophysical Properties Of Solventsmentioning

confidence: 99%

Solvent selection and design for CO₂capture – how we might have been missing the point

Mota-Martinez

Hallett

Dowell

2017

Sustainable Energy Fuels

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Revisiting film theory to consider approaches for enhanced solvent-process design for carbon capture

Cited by 35 publications

References 49 publications

Micro-scale CFD modeling of reactive mass transfer in falling liquid films within structured packing materials

Micro-scale CFD modeling of reactive mass transfer in falling liquid films within structured packing materials

Measuring the Absorption Rate of CO₂ in Nonaqueous CO₂‐Binding Organic Liquid Solvents with a Wetted‐Wall Apparatus

Solvent selection and design for CO₂capture – how we might have been missing the point

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Revisiting film theory to consider approaches for enhanced solvent-process design for carbon capture

Cited by 35 publications

References 49 publications

Micro-scale CFD modeling of reactive mass transfer in falling liquid films within structured packing materials

Micro-scale CFD modeling of reactive mass transfer in falling liquid films within structured packing materials

Measuring the Absorption Rate of CO2 in Nonaqueous CO2‐Binding Organic Liquid Solvents with a Wetted‐Wall Apparatus

Solvent selection and design for CO2capture – how we might have been missing the point

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Measuring the Absorption Rate of CO₂ in Nonaqueous CO₂‐Binding Organic Liquid Solvents with a Wetted‐Wall Apparatus

Solvent selection and design for CO₂capture – how we might have been missing the point