Patent ID: 8667913

Claim:
A device for controlling a retention time of a fluid medium in a fluidized-bed gasification furnace in a gasification facility including a gasification furnace having a fluidized bed of a fluid medium formed with steam to gasify a charged raw material for production of a gasification gas and a combustible solid, a combustion furnace into which the combustible solid produced by said gasification furnace is introduced along with the fluid medium to form a fluidized bed with a fluidizing gas to burn the combustible solid and a fluid-medium separator which separates a fluid medium from a combustion exhaust gas introduced from the combustion furnace to supply the separated fluid medium to the gasification furnace the device comprising: a plurality of fluid-medium charge ports connected to said gasification furnace at intervals from an upstream end thereof toward a downstream side in a distribution direction of the fluid medium longitudinally of the gasification furnace; fluid-medium charge switching means for guiding the fluid medium separated by the fluid-medium separator to any one of the fluid-medium charge ports; a plurality of raw-material charge ports connected to the gasification furnace at intervals from an upstream end thereof toward a downstream side in the distribution direction of the fluid medium longitudinally of the gasification furnace correspondingly to the plural fluid-medium charge ports; a raw-material charge switching means for guiding the raw material to any one of the plural raw-material charge ports; and a fluid-medium extraction port connected to said gasification furnace at a longitudinally downstream end thereof in distribution direction of the fluid medium for extracting and guiding the fluid medium from said gasification furnace to said combustion furnace.