Dissolution of residual non-aqueous phase liquids in porous media: pore-scale mechanisms and mass transfer rates

Sahloul, Nahla; Ioannidis, Marios A.; Chatzis, Ioannis

doi:10.1016/s0309-1708(01)00025-2

Cited by 81 publications

(65 citation statements)

References 22 publications

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“…The presented work can find applications in understanding the chemical reactive transport, [16] describing the transport in a conduit with solute stored in the porous matrix block, [9][10][11][12][13]17] and modelling of non-aqueous phase liquid (NAPL) dissolution. [18] However, the following main features make this study distinct from previous theoretical studies. First, analytical expressions for the effective advection coefficient, the dispersion coefficient, and the effective Sherwood number during the chemical species transport in a tube with a constant wall concentration are presented.…”

Section: Introductionmentioning

confidence: 87%

A reduced‐order model for chemical species transport in a tube with a constant wall concentration

Dejam

Chen

2017

Can J Chem Eng

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A two-dimensional advection-diffusion model accompanied with a parabolic velocity profile of Poiseuille flow is considered for the chemical species transport in a tube with a constant wall concentration. The Reynolds decomposition technique is applied to reduce it to an equivalent one-dimensional model for advective-dispersive transport in a tube through which the effective advection coefficient, the dispersion coefficient, and the effective Sherwood number are developed for the problem under study. The derived and the classical Taylor models are also compared in order to find the difference between the two arrangements. The reduced-order model for the transport equation shows that the effective advection coefficient increases, whereas the dispersion coefficient in the tube decreases as compared to the classical Taylor equation. The effective Sherwood number for the steady state form of the developed model is found to be only a function of the Peclet number, which varies in the range of 3.215 Sh 4. These results find application in design of experiments and improve our understanding of mass transfer in microfluidic devices.

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Section: Introductionmentioning

confidence: 87%

A reduced‐order model for chemical species transport in a tube with a constant wall concentration

Dejam

Chen

2017

Can J Chem Eng

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“…In such cases, hydrostatic equilibrium may be temporarily lost as groundwater tends to mound around the free LNAPL plume. When groundwater seeks to re-establish its equilibrium, it may trap part of the LNAPL plume under the water table (Hamed et al, 2000;Sahloul et al, 2002). These trapped residual LNAPL, also known as isolated ganglia or blobs, act as individual sources and generate discontinuous plumes …”

Section: Btex Physical and Chemical Propertiesmentioning

confidence: 99%

“…However, in groundwater, the contaminants are often present as discontinuous plumes. In case of non-aqueous phase liquid (NAPL), discontinuous plumes can result from trapped residual NAPL (Hamed et al, 2000;Sahloul et al, 2002). The discontinuity of the plumes results in periodic absence of the contaminants in the PRBB.…”

Section: Gel Electrophoresismentioning

confidence: 99%

“…The transport of a contaminant or a mixture of contaminants in groundwater is unpredictable and can come in batches or discontinuous plumes as a result from trapped residual non aqueous phase liquids (Sahloul et al, 2002). Random disappearance of the target contaminants could cause a possible loss of some of the contaminant degraders and/or the biodegradation activity (Kasi et al, 2011), which are necessary for interspecies interactions for the biodegradation of contaminant mixture.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

In situ Groundwater Remediation Using Enricher Reactor – Permeable Reactive Biobarrier

Kasi¹,

McEvoy²,

Padmanabhan³

et al. 2010

proc water environ fed

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Permeable reactive biobarrier (PRBB) is a flow-through zone where microorganisms degrade contaminants in groundwater. Discontinuous presence of contaminants in groundwater causes performance loss of a PRBB in removing the target contaminant. A novel enricher reactor (ER) -PRBB system was developed to treat groundwater with contaminants that reappear after an absence period. ER is an offline reactor for enriching contaminant degraders, which were used for augmenting PRBB to maintain its performance after a period of contaminant absence. The ER-PRBB concept was initially applied to remove benzene that reappeared after absence periods of 10 and 25 days. PRBBs without ER augmentation experienced performance losses of up to 15% higher than ER-PRBBs.The role of inducer compounds in the ER to enrich bacteria that can degrade a mixture of benzene, toluene, ethylbenzene, and xylene (BTEX) was investigated with an objective to minimize the use of toxic chemicals as inducers. Three inducer types were studied: individual BTEX compounds, BTEX mixture, and benzoate (a non toxic and a common intermediate for BTEX biodegradation). Complete BTEX removal was observed for degraders enriched on all three inducer types; however, the removal rates were dependent on the inducer type. Degraders enriched on toluene and BTEX had the highest degradation rates for BTEX of 0.006 to 0.014 day -1 and 0.006 to 0.012 day -1 , respectively, while degraders enriched on benzoate showed the lowest degradation rates of 0.004 to 0.009 day -1 .The ER-PRBB technique was finally applied to address the performance loss of a PRBB due to inhibition interactions among BTEX, when the mixture reappeared after a iv 10 day absence period. The ER-PRBBs experienced minimal to no performance loss, while PRBBs without ER augmentation experienced performance losses between 11% and 35%. Presence of ethanol during the BTEX absence period increased the performance loss of PRBB for benzene removal. PRBBs augmented with degraders enriched on toluene alone overcame the inhibition interaction between benzene and toluene indicating that toluene can be used as a single effective inducer in an ER. The ER-PRBB was demonstrated to be a promising remediation technique and has potential for applications to a wide range of organic contaminants.v ACKNOWLEDGEMENTS

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“…In addition, interface surfaces play an important role as many physicochemical processes with industrial relevance take place on or across interfaces, e.g. the preferential adsorption at the o/w interface of tracer nano-particles (Ryoo et al, 2010) and other species (Serres-Piole et al, 2012), or the rate of dissolution of the non-wetting in the wetting phase (Sahloul et al, 2002) directly related to the surface area per unit p.m. volume, have a strong impact on the spreading of contaminants in groundwater aquifers, the storage of CO 2 in brine filled formations, the efficient operation of PEM fuel cells (Bazylak et al, 2008) or trickle-bed reactors (Van de Merwe and Nicol, 2009) and other industrial applications.…”

Section: Introductionmentioning

confidence: 99%

Oil Fragmentation, Interfacial Surface Transport and Flow Structure Maps for Two-Phase Flow in Model Pore Networks. Predictions Based on Extensive, DeProF Model Simulations

Valavanides

2018

Oil & Gas Science and Technology - Rev. IFP Energies nouvel

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-In general, macroscopic two-phase flows in porous media form mixtures of connectedand disconnected-oil flows. The latter are classified as oil ganglion dynamics and drop traffic flow, depending on the characteristic size of the constituent fluidic elements of the non-wetting phase, namely, ganglia and droplets. These flow modes have been systematically observed during flow within model pore networks as well as real porous media. Depending on the flow conditions and on the physicochemical, size and network configuration of the system (fluids and porous medium), these flow modes occupy different volume fractions of the pore network. Extensive simulations implementing the DeProF mechanistic model for steady-state, one-dimensional, immiscible twophase flow in typical 3D model pore networks have been carried out to derive maps describing the dependence of the flow structure on capillary number, Ca, and flow rate ratio, r. The model is based on the concept of decomposition into prototype flows. Implementation of the DeProF algorithm, predicts key bulk and interfacial physical quantities, fully describing the interstitial flow structure: ganglion size and ganglion velocity distributions, fractions of mobilized/stranded oil, specific surface area of oil/water interfaces, velocity and volume fractions of mobilized and stranded interfaces, oil fragmentation, etc. The simulations span 5 orders of magnitude in Ca and r. Systems with various viscosity ratios and intermediate wettability have been examined. Flow of the nonwetting phase in disconnected form is significant and in certain cases of flow conditions the dominant flow mode. Systematic flow structure mutations with changing flow conditions have been identified. Some of them surface-up on the macroscopic scale and can be measured e.g. the reduced pressure gradient. Other remain in latency within the interstitial flow structure e.g. the volume fractions of À or fractional flows of oil through À connected-disconnected flows. Deeper within the disconnected-oil flow, the mutations between ganglion dynamics and drop traffic flow prevail. Mutations shift and/or become pronounced with viscosity disparity. They are more evident over variables describing the interstitial transport properties of process than variables describing volume fractions. This characteristic behavior is attributed to the interstitial balance between capillarity and bulk viscosity. Mean mobilization probability of i-class ganglia S 2.3 IFP Energies nouvelles International Conference Rencontres Scientifiques d'IFP Energies nouvellesNumber density of i-class ganglia S (15)Number of pore unit cells occupied by each i-class ganglion P

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Dissolution of residual non-aqueous phase liquids in porous media: pore-scale mechanisms and mass transfer rates

Cited by 81 publications

References 22 publications

A reduced‐order model for chemical species transport in a tube with a constant wall concentration

A reduced‐order model for chemical species transport in a tube with a constant wall concentration

In situ Groundwater Remediation Using Enricher Reactor – Permeable Reactive Biobarrier

Oil Fragmentation, Interfacial Surface Transport and Flow Structure Maps for Two-Phase Flow in Model Pore Networks. Predictions Based on Extensive, DeProF Model Simulations

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