In-situ coal drying
AssigneeShell Mining Company
InventorsMark A. Siddoway, Timothy S. Westby
Life of this patent
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Abstract
A method for upgrading coal in-situ is disclosed in which a treatment zone is established around an energy source placed in a cavity within a coal seam and the pore structure of the coal substantially irreversibly collapses as moisture is driven off. The energy source provides either evaporative energy such as heat or a combination of heat and pressure in-situ. Resorption of water returning to the treatment zone during cooling of the coal prior to mining is limited due to the pore collapse.
Claims21
A method for mining coal upgraded within a coal seam comprising:
- creating a cavity within the coal seam;
- placing a source of energy within the cavity, effective to substantially irreversibly collapse pores within a treatment zone in the coal seam;
- activating the energy source;
- driving pore moisture from the coal;
- substantially irreversibly collapsing pores in the coal within the treatment zone of the coal seam, thereby reducing the ability of the coal to resorb pore moisture;
- and
- removing the upgraded coal from the seam.
A method for mining coal comprising:
- creating a cavity within a seam of coal;
- injecting steam into the cavity to elevate the temperature of the coal and increase the local pressure;
- maintaining the localized pressure in the cavity above the vapor pressure of water at the elevated temperature until substantially irreversible pore collapse reduces the pore moisture within the coal in a treatment zone;
- and
- removing the upgraded coal from the coal seam.
A method for mining coal in a coal seam comprising:
- establishing a treatment zone within the coal seam;
- evaporating moisture from the coal within the treatment zone to form water vapor;
- driving the water vapor evaporated from the coal out of the treatment zone;
- and
- removing the upgraded coal from the coal seam.
A method for mining coal in a coal seam comprising:
- creating a cavity within the coal seam;
- placing a source of evaporative energy within the cavity;
- activating the source of evaporative energy;
- evaporating moisture from the coal within a treatment zone adjacent the activated source of evaporative energy to form water vapor comprising the following steps:
- evaporating surface moisture from the coal in the treatment zone;
- and
- evaporating pore moisture from the coal in the treatment zone causing irreversible pore collapse;
- driving the water vapor from the coal out of the treatment zone;
- deactivating the source of evaporative energy;
- allowing the coal to cool and the water vapor to condense and partially migrate back to the treatment zone where the saturation level of the coal has been reduced due to the irreversible pore collapse;
- and
- removing the upgraded coal from the coal seam.
Dependencies are inferred from the claim text.