Patent ID: 7569086

Claim:
A method of converting a carbonaceous material into a product gas, the method comprising: providing a fluid bed reformer comprising: a reaction vessel defining a compartment suitable for receiving carbonaceous material; a first cluster of heating conduits at least partially occupying said compartment and extending over a first vertical extent within the compartment, each heating conduit in the first cluster configured to transfer heat from a heat source to the compartment, the heating conduits in the first cluster having a first thickness; and a second cluster of beating conduits at least partially occupying said compartment and extending over a second vertical extent within the compartment, each heating conduit in the second cluster configured to transfer heat from a heat source to the compartment, the heating conduits in the second cluster having a second thickness, the second cluster of heating conduits being positioned vertically above the first cluster of heating conduits and spaced apart therefrom by a first separation distance, the first separation distance being at least as large as the smaller of the first and second thicknesses, the first separation distance defining a zone in the reaction vessel between the first cluster and second cluster that is configured to be conducive to good solids circulation; introducing a fluidization medium into the compartment; introducing carbonaceous material into the compartment in a region that is vertically between the first and second clusters of heating conduits; and controlling a reaction in the reaction vessel such that at least a portion of the carbonaceous material is converted into a product gas in a fluidized bed.