The University of Queensland

Reactive Transport in Porous Media



New approaches to transport and chemical reactions in porous media

The conditional methodology, which has been proven very successful in modelling of turbulent reactive flows, is extended to simulate reactive flows through porous media. Conditional models take into account variations in gas species concentrations between pores and inter-pore locations allowing for a more accurate (as compared to unconditional models) and consistent treatment of heterogeneous reactions. Different versions of conditional models have been formulated [1-4]. Some of the models were specifically designed for consistent modelling of multi-cascade processes of reactive transport in complex porous media. One of the conditional models, PDCMC, was formulated for and applied to simulation of CH4 replacement by CO2 in coal and demonstrated a good agreement with the experimental data [3].

While conditional models represent effective tools for evaluation of reactive transport in porous media, the problem of determining the model coefficients is not fully resolved within the conditional methods. A general approach, which allows us to derive analytical expressions for the transport coefficients in porous media (both conditional and unconditional), is suggested to resolve this problem [5]. This approach combines two classical approaches -- the effective medium approximation and the macroscopic continuum model analogous to the Fokker-Planck equation -- into single, general and powerful methodology, which can deal with irregular porous media while taking into account percolation effects. There is no need for excessive detail or computational effort. A brief overview of conditional methods developed for reacting flows in porous media is given in [6]

Theory of flames in combustible porous media (with applications to coal combustion and gasification)

Propagation and stability of curved flames in porous combustible media have been studied in the context of Underground Coal Gasification (UCG,[7]). A theory for reverse flame propagation, which explains a number of experimentally observed phenomena, has been suggested [8]. The theory demonstrates that only near-stoichiometric flames are stable and relates the formation of a channel in the reverse combustion linking to this stability condition. The developed approach also involved a comparison of different regimes of both co-current and counter-current combustion [9] and for the elaboration of the optimal regimes [10].

In addition, stability of the evaporation front in porous media is studied in [11] and the theory that describes two possible regimes for flame propagation (upstream and downstream) in a channel with combustible walls has also been introduced and shown to qualitatively agree with experiments [12].

References

  1. A. Y. Klimenko and M. M. Abdel-Jawad, Conditional methods for continuum reacting flows in porous media, Proceedings of Combustion Institute, Vol. 31, 2007, pp. 2107-2115.
  2. I. G. Vladimirov and A. Y. Klimenko, Tracing diffusion in porous media with fractal properties , Multiscale Modeling and Simulation, Vol. 8(4), 2010, pp. 1178-1211.
  3. A. Y. Klimenko, D. N. Saulov, P. Massarotto, V. Rudolph, Conditional model for sorption in porous media with fractal properties, Transport in Porous Media, Vol. 92(3), 2012, pp. 745-765
  4. D. Saulov, C. Chodankar, M. Cleary, A. Klimenko, Coupling the porous conditional moment closure with the random pore model , Frontiers of Chemical Science and Engineering, Vol. 6(1), 2012, pp. 84-93
  5. D. A. Klimenko, K. Hooman, A. Y. Klimenko, Evaluating transport in irregular pore networks, Physical Review E, Vol. 86(1), 2012, pp. 011112.1-011112.11.
  6. D. N. Saulov, M. M. Zhao, M. J. Cleary, D. A. Klimenko, K. Hooman, and A. Y. Klimenko, General Approach for Modelling of Reactive Transport in Porous Media, International Journal of Chemical Engineering and Applications, Vol. 3, No. 6, 2012, 471.


  7. A.Y. Klimenko, Early ideas in underground coal gasification and their evolution, Energies, Vol.2, 2009, pp.456-476
  8. M.S. Blinderman and A.Y. Klimenko, Theory of reverse combustion linking, Combustion and Flame, Vol.150, 2007, pp. 232-245
  9. M.S. Blinderman, D.N. Saulov and A.Y. Klimenko, Forward and reverse combustion linking in underground coal gasification, Energy, Vol. 33 (3), 2008, pp. 446-454
  10. M.S. Blinderman, D.N. Saulov and A.Y. Klimenko, Exergy optimisation of the reverse combustion linking in underground coal gasification, Journal of the Energy Institute, Vol. 81, 2008, pp. 7-13
  11. O.A. Plumb and A.Y. Klimenko, The stability of evaporating fronts in porous media, Journal of Porous Media, Vol. 13(2), 2010, pp. 145-155
  12. D.N. Saulov, O.A. Plumb and A.Y. Klimenko, Flame propagation in a gasification channel, Energy, Vol. 35(3), 2010, pp. 1264-1273

Links

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