Fluidized bed furnace

Abstract

Provided is a fluidized bed furnace for heating waste to extract a combustible gas from the waste, including: a plurality of wind boxes arranged on a lower side of a bottom wall of a furnace body to blow a fluidizing gas into the fluidized bed; a plurality of temperature detection sections disposed at respective positions allowing detection of temperatures of an upper position and a lower position vertically spaced in a first region, and allowing detection of temperatures of upper and lower positions vertically spaced in a second region; and a control section operable, based on the temperatures detected by the temperature detection sections, to adjust an air ratio of the fluidizing gas to be fed to each of the wind boxes, so that the temperature of the fluidized bed is raised in a direction from the first region toward the second region.

What is claimed is: 
     
         1 . A fluidized bed furnace for heating waste to extract a combustible gas from the waste, comprising:
 a furnace body having a bottom wall which supports fluidizable particles from therebelow so as to make up a fluidized bed for heating the waste, and a sidewall standing upwardly from the bottom wall, wherein the bottom wall has a discharge port provided at a position offset from a center position of the bottom wall in a specific direction to discharge non-combustible substances in the waste together with a part of the fluidizable particles, and an upper surface of the bottom wall is inclined to become lower toward the discharge port so as to cause the non-combustible substances to fall on the upper surface of the bottom wall toward the discharge port;   a gas supply section for blowing a fluidizing gas from the bottom wall of the furnace body toward the fluidizable particles to fluidize the fluidizable particles;   a plurality of temperature detection sections for detecting a temperature of the fluidized bed;   a control section for controlling the gas supply section; and   a waste supply section for supplying waste from a supply-side portion of the sidewall located on a side opposite to the discharge port across the center position of the bottom wall, to a region on the fluidized bed, the region being adjacent to the supply-side sidewall portion,   wherein:   the gas supply section includes a plurality of wind boxes each of which is provided on a lower side of the bottom wall to extend in a direction orthogonal to a direction from the supply-side sidewall portion toward the discharge port and adapted to blow the fluidizing gas from a given position in the orthogonal direction toward the fluidizable particles, and a feeding unit adapted to feed the fluidizing gas to each of the wind boxes in a manner capable of adjusting an air ratio of the fluidizing gas to be fed to each of the wind boxes, individually, wherein the plurality of wind boxes are arranged side-by-side in the direction from the supply-side sidewall portion toward the discharge port;   the plurality of temperature detection sections are arranged at respective positions allowing detection of temperatures of an upper position and a lower position which are vertically spaced in a first region of the fluidized bed, the first region being vertically overlapping with a first one of the wind boxes closest to the supply-side sidewall portion, and allowing detection of temperatures of an upper position and a lower position which are vertically spaced in a second region of the fluidized bed, the second region being vertically overlapping with the discharge port or a second one of the wind boxes closest to the discharge port; and   the control section is operable to adjust an air ratio of the fluidizing gas to be fed from the feeding unit to each of the wind boxes, individually, based on the temperatures detected by the temperature detection sections, so as to make the temperature of the fluidized bed be raised in a direction from the first region toward the second region.   
     
     
         2 . The fluidized bed furnace as defined in  claim 1 , wherein specific ones of the plurality of temperature detection sections are allocated between the first region and the second region of the fluidized bed, and wherein the specific temperature detection sections are arranged so as to be capable of detecting of temperatures at respective positions at given intervals in the direction from the supply-side sidewall portion toward the discharge port. 
     
     
         3 . The fluidized bed furnace as defined in  claim 2 , wherein the specific temperature detection sections allocated between the first region and the second region are arranged so as to be capable of detecting of temperatures at respective positions in each of one or more regions of the fluidized bed, the regions being vertically overlapping with respective ones of the remaining one or more wind boxes disposed between the first wind box and the second wind box. 
     
     
         4 . The fluidized bed furnace as defined in  claim 3 , wherein, in each of the one or more regions between the first region and the second region, and at a position vertically overlapping with respective ones of the remaining one or more wind boxes, the specific temperature detection sections are arranged so as to be capable of detecting of temperatures at respective positions of an upper position and a lower position which are vertically spaced.