Enhancement of dilution and transverse reactive mixing in porous media: Experiments and model-based interpretation

Rolle, Massimo; Eberhardt, Christina; Chiogna, Gabriele; Cirpka, Olaf A.; Grathwohl, Peter

doi:10.1016/j.jconhyd.2009.10.003

Cited by 177 publications

(218 citation statements)

References 44 publications

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“…Greater initial . The contrast in the image shown in the inset was enhanced to better show the mineral layer within and on both sides of the inclusion dispersion within and downstream of the high permeability inclusion is consistent with the dependence of dispersion on velocity (which is higher in and downstream of the inclusion) observed by Rolle et al (2009) and with the dependence on grain size recorded by Xu and Eckstein 1997. After precipitation in the high permeability inclusion experiment, transverse mixing appeared to be uniform along the length of the interface, even in the inclusion (Fig.…”

Section: Experimental Observationssupporting

confidence: 81%

Experimental and Numerical Analysis of Parallel Reactant Flow and Transverse Mixing with Mineral Precipitation in Homogeneous and Heterogeneous Porous Media

et al. 2015

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Formation of mineral precipitates in the mixing interface between two reactant solutions flowing in parallel in porous media is governed by reactant mixing by diffusion and dispersion and is coupled to changes in porosity/permeability due to precipitation. The spatial and temporal distribution of mixing-dependent precipitation of barium sulfate in porous media was investigated with side-by-side injection of barium chloride and sodium sulfate solutions in thin rectangular flow cells packed with quartz sand. The results for homogeneous sand beds were compared to beds with higher or lower permeability inclusions positioned in the path of the mixing zone. In the homogeneous and high permeability inclusion experiments, BaSO 4 precipitate (barite) formed in a narrow deposit along the length and in the center of the solution-solution mixing zone even though dispersion was enhanced within, and downstream of, the high permeability inclusion. In the low permeability inclusion experiment, the deflected BaSO 4 precipitation zone broadened around one side and downstream of the inclusion and was observed to migrate laterally toward the sulfate solution. A continuum-scale fully coupled reactive transport model that simultaneously solves the nonlinear governing equations for fluid flow, transport of reactants and geochemical reactions was used to simulate the experiments and provide insight into mechanisms underlying the experimental observations. Migration of the precipitation zone in the low permeability inclusion experiment could be explained by the coupling effects among fluid flow, reactant transport and localized mineral precipitation reaction.

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Section: Experimental Observationssupporting

confidence: 81%

Experimental and Numerical Analysis of Parallel Reactant Flow and Transverse Mixing with Mineral Precipitation in Homogeneous and Heterogeneous Porous Media

et al. 2015

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“…The model is based on a particle-tracking method that uses a streamline method to capture advection (Pereira Nunes et al 2015) and a random walk to simulate diffusion with a probability of reaction (P r ) to represent the chemical kinetics. Dynamic changes in reaction rate in a beadpack were predicted accurately and shown to be affected not only by incomplete mixing as it had been demonstrated before experimentally (Raje and Kapoor 2000;Gramling et al 2002;Jose and Cirpka 2004;Rolle et al 2009;Edery et al 2015) and numerically (Edery et al 2010;Bolster et al 2010;Dentz et al 2011;Ding et al 2013;Hochstetler and Kitanidis 2013), but also as a result of early-time pre-asymptotic spreading (Alhashmi et al 2015). The characterization of the pre-asymptotic behavior through a continuum-scale model has been recently discussed by Porta et al (2016), based on previous work by Porta et al (2012).…”

Section: Introductionmentioning

confidence: 67%

The Impact of Pore Structure Heterogeneity, Transport, and Reaction Conditions on Fluid–Fluid Reaction Rate Studied on Images of Pore Space

2016

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We perform direct numerical simulation using a pore-scale fluid-fluid reactive transport model (Alhashmi et al. in J Contam Hydrol 179:171-181, 2015. doi:10.1016/j. jconhyd.2015 to investigate the impact of pore structure heterogeneity on the effective reaction rate in different porous media. We simulate flow, transport, and reaction in three pore-scale images: a beadpack, Bentheimer sandstone, and Doddington sandstone for a range of transport and reaction conditions. We compute the reaction rate, velocity distributions, and dispersion coefficient comparing them with the results for non-reactive transport. The rate of reaction is a subtle combination of the amount of mixing and spreading that cannot be predicted from the non-reactive dispersion coefficient. We demonstrate how the flow field heterogeneity affects the effective reaction rate. Dependent on the intrinsic flow field heterogeneity characteristic and the flow rate, reaction may: (a) occur throughout the zones where both resident and injected particles exist (for low Péclet number and a homogeneous flow field), (b) preferentially occur at the trailing edge of the plume (for high Péclet number and a homogeneous flow field), or (c) be disfavored in slow-moving zones (for high Péclet number and a heterogeneous flow field).

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“…Likewise, if a plume fringe passes through a low-conductivity zone, where the transverse diffusion length is increased, the mass transfer across streamlines is slowed down. The importance of high-conductivity inclusions as hot spots of transverse mixing and mixing-controlled reactions have been demonstrated in several experimental studies (e.g., Bauer et al, 2009a;Cirpka et al, 1999d;Rolle et al, 2009). In numerical experiments, Werth et al (2006) showed that the average net effect of heterogeneity on transverse solute mixing is an enhancement, implying that the decrease of transverse mixing in low-conductivity zones is overbalanced by the increase in high-conductivity zones.…”

Section: Introductionmentioning

confidence: 93%

Stochastic evaluation of mixing-controlled steady-state plume lengths in two-dimensional heterogeneous domains

Cirpka

Rolle

Chiogna

et al. 2012

Journal of Contaminant Hydrology

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Enhancement of dilution and transverse reactive mixing in porous media: Experiments and model-based interpretation

Cited by 177 publications

References 44 publications

Experimental and Numerical Analysis of Parallel Reactant Flow and Transverse Mixing with Mineral Precipitation in Homogeneous and Heterogeneous Porous Media

Experimental and Numerical Analysis of Parallel Reactant Flow and Transverse Mixing with Mineral Precipitation in Homogeneous and Heterogeneous Porous Media

The Impact of Pore Structure Heterogeneity, Transport, and Reaction Conditions on Fluid–Fluid Reaction Rate Studied on Images of Pore Space

Stochastic evaluation of mixing-controlled steady-state plume lengths in two-dimensional heterogeneous domains

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