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| Titel |
Underground Coalfires as an Incentive and Challenge to THMC Modeling |
| VerfasserIn |
Manfred W. Wuttke, Christian Fischer, Dorel Gusat, Uwe Meyer, Martin Schmidt |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250041756
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| Zusammenfassung |
| Spontaneous combustion of coal has become a world wide problem often caused by technical
operations in coal mining areas. It affects human activities locally but even more important
globally through the contribution to global warming by emitting substantial amounts of
greenhouse gases like carbondioxid.
Investigations of underground coalfires so far mainly with the aim of their mitigation have
revealed a network of complex interactions between thermal, hydraulic, mechanical and
chemical processes in this unique systems. Numerical modeling at the moment is only at the
brink of being helpful to support the fire fighting in the field, but has already served as a tool
to test the overall understanding of coal fire processes and to estimate their environmental
impacts.
This work aims at summarizing the status of THMC modeling of underground coalfires,
mainly from the perspective of the Sino-German Coalfire Project, and gives an overview of
the open questions and challenges to rise to if one is up to comprehensive and meaningful
modeling work. The main topics are:
The fluid transport through fractured porous media is driven by chemical
processes at high temperatures causing high pressure gradients.
Transport processes occur on different timescales.
Thermal and mechanical stresses cause fracturing in the porous media on a huge
range of scales, thus constantly changing the pathways for oxygen supply and
exhaust gas removal.
To investigate any extinction process one has to consider multi phase transport
with phase changes (evaporation and condensation of water, transport of mud
and cementation, etc.).
To interpret surface signatures like temperature anomalies one has to link the
underground processes to atmospheric heat transport including radiation.
Coal fires are highly individual, threedimensional systems in general without any
symmetry.
Other problems in geoscience and geoengineering (like nuclear waste deposition, geothermal
energy utilization, carbon dioxide sequestration) require a comparably complex approach to
modeling. Although the details make it impossible to apply a single code implementation to
all systems, their investigations go in similar ways. There is a need for modular code systems
with open access for the various communities to maximize the shared synergistic
effects. |
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