Collection of landfill gas at variable rates to match temporal needs for energy generation
First Claim
1. A method of collecting biogas from a landfill having waste and an outer surface contacting the atmosphere, whereinthe landfill contains (i) at or near the outer surface contacting the atmosphere a gas-containment layer that has low gas permeability;
- and (ii) a gas-permeable layer toward the interior of the landfill from the gas-containment layer and toward the exterior of most of the landfill waste mass, the gas-permeable layer having at least 10 times the gas-permeability of the gas-containment layer;
the method comprising;
(a) collecting biogas from the landfill from a location toward the interior of the landfill from the gas-permeable layer with at least one gas-collection well that collects biogas from an extraction location toward the interior of the landfill from the gas-permeable layer and separated by waste from the gas-permeable layer and draws it to the surface, the well comprising a biogas-collecting wellhead at the extraction location and a conduit linking the wellhead to the surface to draw biogas from the wellhead to the surface;
wherein step (a) comprises collecting biogas at a maximal rate for at least one hour and a minimal rate for at least one hour in the same day, wherein the maximal rate of biogas collection in a day is at least 20% more than the minimal rate of biogas collection in the same day for at least two consecutive days.
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Abstract
The invention involves a method of collecting biogas from a landfill with a variable rate of collection varied to match periods of greatest need for energy and greatest economic value of energy during a day. The variable collection rate is made possible by a landfill design that includes a gas permeable layer and a gas containment layer with gas collection from an extraction locus beneath the gas permeable layer. In some embodiments the landfill also includes a porous gas storage layer above the gas-permeable layer.
48 Citations
23 Claims
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1. A method of collecting biogas from a landfill having waste and an outer surface contacting the atmosphere, wherein
the landfill contains (i) at or near the outer surface contacting the atmosphere a gas-containment layer that has low gas permeability; - and (ii) a gas-permeable layer toward the interior of the landfill from the gas-containment layer and toward the exterior of most of the landfill waste mass, the gas-permeable layer having at least 10 times the gas-permeability of the gas-containment layer;
the method comprising; (a) collecting biogas from the landfill from a location toward the interior of the landfill from the gas-permeable layer with at least one gas-collection well that collects biogas from an extraction location toward the interior of the landfill from the gas-permeable layer and separated by waste from the gas-permeable layer and draws it to the surface, the well comprising a biogas-collecting wellhead at the extraction location and a conduit linking the wellhead to the surface to draw biogas from the wellhead to the surface; wherein step (a) comprises collecting biogas at a maximal rate for at least one hour and a minimal rate for at least one hour in the same day, wherein the maximal rate of biogas collection in a day is at least 20% more than the minimal rate of biogas collection in the same day for at least two consecutive days. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
- and (ii) a gas-permeable layer toward the interior of the landfill from the gas-containment layer and toward the exterior of most of the landfill waste mass, the gas-permeable layer having at least 10 times the gas-permeability of the gas-containment layer;
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23. A method of collecting biogas from a landfill wherein the landfill has an outer surface contacting the atmosphere, the method comprising:
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providing the landfill at or near the outer surface contacting the atmosphere with a gas-containment layer that has low gas permeability; providing the landfill with a gas-permeable layer toward the interior of the landfill from the gas-containment layer and toward the exterior of most of the landfill waste mass, the gas-permeable layer having at least 10 times the gas-permeability of the gas-containment layer; providing the landfill with at least one gas-collection well that collects biogas from an extraction location toward the interior of the landfill from the gas-permeable layer and separated by waste from the gas-permeable layer and draws it to the surface, the well comprising a biogas-collecting wellhead at the extraction location and a conduit linking the wellhead to the surface to draw biogas from the wellhead to the surface; and collecting biogas from the landfill toward the interior of the landfill from the gas-permeable layer through the at least one gas-collection well; wherein if any biogas is collected directly from the gas-permeable layer, it is less than 10% of the volume of biogas collected from the landfill from the extraction location toward the interior of the landfill through the at least one gas-collection well.
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Specification