Patent ID: 8105401

Claim:
A method comprising: selecting a downdraft gasifier comprising: a housing, a refractory stack contained within the housing and comprising a plurality of sections formed of refractory, the plurality of sections comprising a lower manifold, at least one intermediate section resting on and extending upward from the lower manifold, and an upper manifold resting on and extending upward from the at least one intermediate section, and the refractory stack wherein the upper manifold and the at least one intermediate section each comprise a plurality of apertures extending vertically therethrough, the plurality of apertures of the upper manifold aligning with the plurality of apertures of the at least one intermediate section to form a plurality of columnar cavities, each extending from the upper manifold to the lower manifold and placing the upper manifold in communication with the lower manifold; placing a feedstock into the upper manifold; measuring the temperature of each columnar cavity of the plurality of columnar cavities; and adjusting the flow of at least one gas selected from the group consisting of oxygen, oxygen enriched air, and air to a particular columnar cavity to maintain the temperature of the particular columnar cavity within a particular range.