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US 8,546,636 B1Granted
Method for gasifying feedstock
AssigneePHG Energy, LLC
InventorsDeon John Potgieter, Billy Freeman Hopper, Jeffrey Scott Brown, Mark Oliver Loftin
Life of this patent
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Abstract
A method of gasification using a downdraft gasifier having a plurality of vertically positioned tubes to create a pyrolysis zone, an oxidation zone beneath the pyrolysis zone and a reduction zone beneath the oxidation zone. The shape of the tubes eliminates the need for a restriction (hearth) in the gasifier, which limits the maximum achievable throughput. A rotating and vertically adjustable grate is located beneath, but not attached to, the reduction zone of the gasifier.
Claims23
A method of gasifying feedstock comprising:
- Filling a gasifier with feedstock;
- said gasifier comprising a plurality of conjoined and vertically positioned tubes having an interior wall, an exterior wall, a proximal end and a distal end, wherein the proximal end provides an inlet and the distal end provides an outlet, a pyrolysis zone, an oxidation zone and a reduction zone;
- Igniting the feedstock to create an oxidation band;
- Injecting oxidant streams into the oxidation zone using at least two rings of plano air inlets;
- Moving feedstock sequentially through the pyrolysis zone where the feedstock begins to fluidize and decompose, then an oxidation zone where the feedstock changes to producer gas and then a reduction zone where the producer gas mixes with biochar to cool and form additional producer gas;
- Holding feedstock and a bed of biochar inside the gasifier using a rotating and vertically adjustable grate positioned below the reduction zone;
- Removing biochar and producer gas through a bypass and holes in the grate;
- and
- Refilling the gasifier with feedstock.
6 more elements
Dependencies are inferred from the claim text.