Fluid bed reactor having vertically spaced apart clusters of heating conduits

A method of thermochemically or biochemically processing a reactive material to form a product, the method comprising:

• providing a fluid bed reactor comprising:
• a reaction vessel defining a compartment suitable for receiving a reactive 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 heating 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 reactive material into the compartment in a region that is vertically between the first and second clusters of heating conduits;
• heating contents of the compartment via the heating conduits;
• and
• controlling a reaction in the reaction vessel such that at least a portion of the reactive material is converted into one or more products in a fluidized bed.