NOVELTY - A mixing apparatus (300A, 300B) comprises at least one mixing vessel (310A, 310B) containing a cylindrical vessel (407) with a conical bottom; a steam inlet configured for introducing steam into the conical bottom; a carbonaceous material inlet configured for introducing a carbonaceous feed into the cylindrical vessel; and an outlet for a reformer (400A) feedstock having at least 0.3 pounds of steam per pound of carbonaceous material, where the mixing vessel is configured for operation at a pressure of greater than 10 psig.    USE - As mixing apparatus for producing a feedstock for a reformer (claimed).    ADVANTAGE - The mixing apparatus enables environmentally-friendly production of synthesis gas, by allowing the use of sustainable and renewable feedstocks such as biomass, facilitating sequestration of carbon dioxide and/or reducing the amount of waste material produced.    DETAILED DESCRIPTION - A mixing apparatus (300A, 300B) comprises at least one mixing vessel (310A, 310B) containing a cylindrical vessel (407) with a conical bottom; a steam inlet configured for introducing steam into the conical bottom; a carbonaceous material inlet configured for introducing a carbonaceous feed into the cylindrical vessel; and an outlet for a reformer (400A) feedstock having at least 0.3 pounds of steam per pound of carbonaceous material, where the mixing vessel is configured for operation at a pressure of greater than 10 psig. The mixing apparatus further comprise at least one mixing vessel outlet lines fluidly connected with the reformer via a distributor, where the reformer feedstock can be introduced into coiled tubes (410A, 410B) within the reformer; and at least one feed preparation apparatus upstream of the mixing vessel.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a synthesis gas production system.    Mixing apparatus (300A, 300B)    Mixing vessel (310A, 310B)    Reformer (400A)    Cylindrical vessel (407)    Coiled tubes (410A, 410B)