Diffusive Reactive Transport of Multicomponent Chemicals Under Coupled Thermal, Hydraulic, Chemical and Mechanical Conditions

Thomas, Hywel Rhys; Sedighi, Majid; Vardon, Philip J.

doi:10.1007/s10706-012-9502-9

Cited by 50 publications

(30 citation statements)

References 20 publications

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“…Previous works have coupled the transport model (COMPASS) with chemical models, for example 257 MINTEQA2 ) and PHREEQC (version 258 2) (Thomas, Sedighi et al 2012, Sedighi, Thomas et al 2015, enabling the study of a range of 259 geoenvironmental and geoenergy problems involving multiphase, multicomponent chemical transport 260 D r a f t in single porosity geomaterials with homogenous and heterogeneous reactions. While an extension of 261 this coupling to the dual porosity framework is not part of the present developments, which are more 262 concerned with transport processes than chemical reactions, it is considered for future development as 263 has already been accomplished in other applications of COMPASS (e.g.…”

Section: Chemical Reactions 256mentioning

confidence: 99%

“…Research Centre by Thomas and co-workers (Thomas and He 1998, 96 Seetharam, Thomas et al 2007, Thomas, Sedighi et al 2012, Sedighi, Thomas et al 2016. 97 COMPASS has a background of high performance simulations of three-dimensional multiphase, 98 multicomponent reactive transport in single porosity geomaterials, based on a theoretical formulation 99 that can be described as a mechanistic approach.…”

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confidence: 99%

“…The governing equations for coupled thermal, hydraulic and aqueous chemical behaviour in 133 unsaturated soils have been covered in detail elsewhere (Thomas and He 1998, Cleall, Seetharam et al 134 2007, Thomas, Sedighi et al 2012, Sedighi, Thomas et al 2016. In addition, the governing equations 135 for the reactive transport of multicomponent gas in a single porosity unsaturated soil have been 136 presented by Masum (2012) and Sedighi et al (2015), assuming ideal gas behaviour.…”

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confidence: 99%

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A dual porosity model of high-pressure gas flow for geoenergy applications

2018

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7This paper presents the development of a dual porosity numerical model of multiphase, 8 multicomponent chemical/gas transport using a coupled thermal, hydraulic, chemical and mechanical 9 formulation. Appropriate relationships are used to describe the transport properties of non-ideal, 10 reactive gas mixtures at high pressure, enabling the study of geoenergy applications such as geological 11 carbon sequestration. Theoretical descriptions of the key transport processes are based on a dual 12 porosity approach considering the fracture network and porous matrix as distinct continua over the 13 domain. Flow between the pore regions is handled using mass exchange terms and the model includes 14 equilibrium and kinetically-controlled chemical reactions. A numerical solution is obtained with a 15 finite element and finite difference approach and verification of the model is pursued to build 16 confidence in the accuracy of the implementation of the dual porosity governing equations. In the 17 course of these tests, the time splitting approach used to couple the transport, mass exchange and 18 chemical reaction modules is shown to have been successfully applied. It is claimed that the modelling 19 platform developed provides an advanced tool for the study of high pressure gas transport, storage and 20 displacement for geoenergy applications involving multiphase, multicomponent chemical/gas 21 transport in dual porosity media, such as geological carbon sequestration. 22

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Section: Chemical Reactions 256mentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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A dual porosity model of high-pressure gas flow for geoenergy applications

2018

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“…Thomas et al, 2012;Yong et al, 2010). In particular, the initial hydration of the compacted clay buffer is important and it is governed by the coupled thermal-hydraulic-mechanical (THM) behaviour.…”

Section: Introductionmentioning

confidence: 99%

“…Dixon et al, 2002;Pusch, 2001;Thomas et al, 2009Thomas et al, , 2012. The majority of processes occurring are driven by the heat produced from the HLW and the water contained within natural bedrock.…”

Section: Introductionmentioning

confidence: 99%

Simulation of repository gas migration in a bentonite buffer

Thomas¹,

Masum²,

Chen³

et al. 2014

Proceedings of the Institution of Civil Engineers - Engineering

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The inventory of high-level radioactive waste in the UK is likely to be disposed of in a geological disposal facility, which will generate gases due to processes such as anoxic metal corrosion and water radiolysis. Such gases have the potential to migrate through the repository system and may be detrimental to the engineered barrier system by damaging the physical fabric of the buffer material through the build-up of pressure. An investigation into the migration of gases and the ranges of gas pressures expected in such a repository is presented. A model of gas transport is presented to simulate the transport of gases in conjunction with coupled thermo-hydro-chemical-mechanical processes. This model includes a boundary condition linking the corrosion behaviour to gas generation and water supply. A realistic range of gas generation rates has been established from available data alongside realistic ranges of material properties of a bentonite buffer. Numerical simulations were then undertaken for a range of realistic scenarios considering the corrosion processes and buffer properties.It was found that in all realistic cases, including realistic maxima and minima considered, the risk of pneumatic fracture was negligible.

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An analytical model for vapor‐phase volatile organic compound diffusion through landfill composite covers

Xie

Yan

Thomas

et al. 2016

Num Anal Meth Geomechanics

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Summary One‐dimensional mathematical models for vapor‐phase volatile organic compound (VOC) diffusion through composite cover barriers are presented. An analytical solution to the model was obtained by the method of separation of variables. The results obtained by the proposed solution agree well with those obtained by a numerical analysis. Based on the proposed analytical model, the VOC breakthrough curves of five different composite covers are compared. The effects of degree of saturation of geosynthetic clay liner (GCL) or compacted clay liner (CCL) on VOC migration in the composite covers are then presented. Results show that the composite cover barriers provide much better diffusion barriers for VOC than the single CCL. The top surface steady‐state flux for a composite barrier, consisting of a 1.5 mm geomembrane (GM) and a 20 cm CCL, can be 8.3 times lower than that for a 30 cm CCL. The surface steady‐state flux for the case with (1.5 mm GM + 6 mm GCL) was found to be 2.3 times lower than that for the case with (1.5 mm GM + 20 cm CCL). The degree of saturation Sr of the CCL has a great influence on VOC migration in composite covers when Sr is larger than 0.5. The steady‐state flux at the surface of GM for the case with Sr = 0.7 can be 1.8 times lower than that for the case with Sr = 0.2. The proposed analytical model is relatively simple and can be used for verification of complicated numerical models, analysis of experimental data and performance assessment of composite cover barriers. Copyright © 2016 John Wiley & Sons, Ltd.

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Diffusive Reactive Transport of Multicomponent Chemicals Under Coupled Thermal, Hydraulic, Chemical and Mechanical Conditions

Cited by 50 publications

References 20 publications

A dual porosity model of high-pressure gas flow for geoenergy applications

A dual porosity model of high-pressure gas flow for geoenergy applications

Simulation of repository gas migration in a bentonite buffer

An analytical model for vapor‐phase volatile organic compound diffusion through landfill composite covers

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