Method and device for controlling retention time of fluid medium in fluidized-bed gasification furnace in gasification facility
A method and device for controlling retention time of a fluid medium in a fluidized-bed gasification furnace in a gasification facility are provided. A fluid medium is guided to any of a plurality of fluid-medium charge ports connected to a gasification furnace at intervals from an upstream end thereof toward a downstream side in a distribution direction of a fluid medium longitudinally of the gasification furnace. A raw material is guided to any of a plurality of raw-material charge ports connected to the gasification furnace at positions longitudinally of the gasification furnace and correspondingly to the fluid-medium charge ports. The fluid medium is extracted and guided to a combustion furnace from a fluid-medium extraction port connected to a downstream end of the gasification furnace longitudinally thereof in the distribution direction of the fluid medium. Thus, retention time of the fluid medium in the gasification furnace is controlled.
1. 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.
2. A device for controlling a retention time of a fluid medium in a fluidized-bed gasification furnace in a gasification facility as claimed in claim 1 , wherein said fluid-medium charge switching means comprises
a downcomer through which the fluid medium separated from a combustion exhaust gas by the fluid-medium separator flows down;
horizontal seals extending horizontally and branched from a lower end of said downcomer toward the fluid-medium charge ports;
vertical seals extending upward from leading ends of said horizontal seals;
inclined connecting pipes turned downward from upper ends of said vertical seals and connected to said fluid-medium charge ports;
wind boxes capable of delivering a fluidizing gas through distributing plates to said horizontal and vertical seals;
fluidizing-gas supply lines connected to the wind boxes; and
fluidizing-gas switching valves incorporated in said fluidizing-gas supply lines.
3. A device for controlling a retention time of a fluid medium in a fluidized-bed gasification furnace in a gasification facility as claimed in claim 1 , wherein said raw-material charge switching means comprises
raw-material supply lines connected to said raw-material charge ports; and
raw-material switching valves incorporated in said raw-material supply lines.
4. A device for controlling a retention time of a fluid medium in a fluidized-bed gasification furnace in a gasification facility as claimed in claim 2 , wherein said raw-material charge switching means comprises
raw-material supply lines connected to said raw-material charge ports; and
raw-material switching valves incorporated in said raw-material supply lines.
5. A method 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 method comprising:
guiding the fluid medium to any one of 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;
guiding a raw material to one of raw-material charge ports connected to said gasification furnace at positions longitudinally thereof corresponding to said fluid-medium charge port; and
extracting and guiding the fluid medium through a fluid-medium extraction port connected to said gasification furnace at a longitudinally downstream end thereof in the distribution direction of the fluid medium, thereby controlling the retention time of the fluid medium in the gasification furnace.