Patent Publication Number: US-9428701-B2

Title: Fluidized-bed gasification method and facility therefor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a division of U.S. application Ser. No. 12/999,163 filed Dec. 15, 2010, the entire contents of which is incorporated herein by reference. U.S. application Ser. No. 12/999,163 is a National Stage of PCT/JP09/002,662 filed Jun. 12, 2009 and claims the benefit of priority from prior Japanese Patent Application No. 2008-161747 filed Jun. 20, 2008. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a fluidized-bed gasification method and a facility therefor for gasification of raw material, using a fluidized bed. 
     BACKGROUND ART 
     There has been proposed a fluidized-bed gasification facility for gasification of raw material such as coal, biomass or sludge wherein the raw material is supplied to a fluidized-bed gasification furnace preliminarily supplied with hot bed material or fluid medium, a gasification agent being supplied for formation of a fluidized bed to gasify the raw material, resultant produced gas being taken out outside while char produced upon the gasification in the gasification furnace and the bed material are supplied to a fluidized-bed combustion furnace to heat the bed material through fluidized combustion of the char, the heated bed material being supplied again to the fluidized-bed gasification furnace (see Patent Literature 1). 
       FIG. 1  shows a fluidized-bed gasification facility of the above Patent Literature 1. In  FIG. 1 , reference numeral  1  denotes a fluidized-bed combustion furnace into which char produced due to gasification of the raw material and the bed material in a fluidized-bed gasification furnace  2  is introduced through a lower portion of the combustion furnace, air from an air pipe  4  being blown through a bottom wind box  3 . The char and bed material are fluidized and raised by the blown air; the char is burned and the bed material is heated while they are raised. Reference numeral  5  denotes a supplementary fuel port for supply of supplementary fuel to a fluidized bed in the fluidized-bed combustion furnace  1 ; and  6 , a heat exchanger for heat recovery at a top of the combustion furnace  1 . 
     Connected to the top of the combustion furnace  1  through a transfer pipe  7  is a separator  8  in the form of a cyclone and comprising outer and inner cylinders  9  and  10 . Hot fluid including the bed material led out from the combustion furnace  1  to the transfer pipe  7  is tangentially introduced into the outer cylinder  9  where the fluid is centrifuged into the bed material and the exhaust gas. The exhaust gas with fine-grained ash is discharged through the inner cylinder  10  while the bed material  11  with rough-grained unburned char is supplied to the gasification furnace  2  via a downcomer  12  extending downward from a bottom of the outer cylinder in the separator  8 . 
     The fluidized-bed gasification furnace  2  comprises an introduction section  13  into which the bed material  11  separated in the separator  8  is introduced through the downcomer  12 , a gasification section  15  for gasification of raw material  26  supplied from a raw material feeder  14  by heat of the bed material  11 , a communicating section  17  for supply of the bed material  11  in the introduction section  13  through a fluidized bed  16  to the gasification section  15  and a box section  18  extending over bottoms of the sections  13 ,  17  and  15  for supply of the gasification agent such as steam into the gasification furnace  2  and connected with a gasification agent supply line  19 . The separation of the introduction and gasification sections  13  and  15  in the fluidized bed  16  by the communicating section  17  as shown in  FIG. 1  prevents the burnt gas in the fluidized-bed combustion furnace  1  from flowing back through the fluidized-bed gasification furnace  2  to the separator  8 . 
     The char not gasified in the gasification section  15  and the bed material are supplied for circulation to the fluidized-bed combustion furnace  1  via a circulation passage  25  comprising, for example, an overflow pipe, the bed material being heated again by the combustion of the char. 
     When coal is supplied as raw material  26  to be gasified to the gasification section  15 , produced is produced gas  20  mixed with gas components such as hydrogen (H 2 ), carbon monoxide (CO) and methane (CH 4 ); when biomass or the like with a high water content is supplied as raw material  26  to be gasified, produced is produced gas  20  with the above-mentioned gas components containing much steam. The produced gas  20  is taken out via a take-out pipe  21  from the fluidized-bed gasification furnace  2  into a recovery device  22  where the produced gas  20  is separated from fine powder  23  entrained in the gas and is taken out through an inner pipe  24 . The produced gas  20  thus taken out may be pressurized and supplied as fuel to, for example, a gas turbine, or may be supplied to a refinery for production of any target gas from the produced gas  20 . 
     In order to guide the hot fluid from the fluidized bed combustion furnace  1  via the transfer pipe  7  to the separator  8 , particles such as bed material entrained in the hot fluid must be prevented from being separated and accumulated in the transfer pipe  7  to clog the same; it is therefore envisaged that the separator  8  is arranged adjacent to the combustion furnace  1  to make the transfer pipe  7  as short in length as possible. In the construction of  FIGS. 2 and 3 , arranged above lateral corners of the fluidized-bed gasification furnace  2  adjacent to the fluidized-bed combustion furnace  1  are separators  8  and  8 ′ connected respectively via short transfer pipes  7  and  7 ′ to the combustion furnace  1  (see Patent Literature 2). 
     However, in the structure shown in  FIGS. 2 and 3 , the bed material  11  supplied via the downcomers  12  to the corners of the fluidized-bed gasification furnace  2  adjacent to the fluidized-bed combustion furnace  1  is allowed to flow in shortest courses  27  to the circulation passage  25 , so that unreacted char flows out through the circulation passage  25  and a low-temperatured dead space  28  is produced in the gasification furnace  2  at a position away from the combustion furnace  1  where no bed material moves. This makes temperature in the fluidized-bed gasification furnace  2  uneven, disadvantageously resulting in lowering in gasification efficiency of the raw material  26  in the gasification furnace  2 . In the above-mentioned fluidized-bed gasification facility shown in  FIG. 1 , the bed material  11  supplied through the downcomer  12  to the fluidized-bed gasification furnace  2  is allowed to flow in a shortest course to the circulation passage  25 , so that low-temperatured dead spaces where no bed material  11  moves are produced on laterally opposite sides of the shortest course in the gasification furnace  2 . As a result, like the structure of  FIG. 2 , the temperature in the fluidized-bed gasification furnace  2  becomes uneven, disadvantageously resulting in lowering in gasification efficiency of the raw material  26  in the fluidized-bed gasification furnace  2 . 
     In order to overcome this, it has been conceived to provide a heat-resistant partition or partitions for regulation of a travel direction of the bed material  11  so as to move the bed material  11  to the dead space or spaces. In a structure shown in  FIGS. 4 and 5 , two heat-resistant partitions  32  are arranged in a laterally spaced-apart relationship and oppositely with respect to the circulation passage  25  such that the partitions  32  have their base ends firmly attached to a wall  29  of the gasification furnace  2  closest to the fluidized-bed combustion furnace  1  and have tip ends extending toward a wall  30  of the gasification furnace  2  farthest away from the combustion furnace  1  with communicating sections  31  therebetween. Thus, laterally symmetrical and substantially U-shaped circuitous flow passages  33  and  33 ′ are provided in the fluidized-bed gasification furnace  2  which are partitioned by the partitions  32  and in communication with each other at the communicating sections  31 . A separator  8  is arranged above a right-side end in the circuitous flow passage  33  close to the wall  29 , and a separator  8 ′ is arranged above a left-side end in the circuitous flow passage  33 ′ close to the wall  29 . A take-out port  34  is arranged above and centrally of the circuitous flow passages  33  and  33 ′. 
     When the bed material  11  is supplied through the downcomers  12  to the right- and left-side ends of the one and the other circuitous flow passages  33  and  33 ′, respectively, the bed material  11  move through the respective circuitous flow passages  33  and  33 ′ in a direction away from the fluidized-bed combustion furnace  1  and joins via the communicating sections  31  to each other at the central passage toward the circulation passage  25 . As a result, the bed material  11  can be caused to pass every corner without lingering of the bed material  11  in the laterally opposite dead spaces to keep uniform the temperature in the fluidized-bed gasification furnace  2 . 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP 2005-41959A 
         Patent Literature 2: WO 2008/111127A 
       
    
     SUMMARY OF INVENTION 
     Technical Problems 
     However, as throughput of the coal or other raw material is increased, the flow rate of the bed material  11  used to heat the raw material in the fluidized-bed gasification furnace  2  is increased, which leads to increase in size of the gasification furnace  2  as well as further difficulty in passing the bed material  11  to every corner of the gasification furnace  2 , failing to produce a desired gasification amount and resulting in discharge of unreacted char. When the movement of the bed material  11  is restricted by, for example, arranging the heatresistant partitions  32  in the fluidized-bed gasification furnace  2  as in the construction of  FIGS. 4 and 5 , disadvantageously the gasification furnace  2  becomes complicated in structure and production cost increases. 
     The invention was made in view of the above and has its object to provide a fluidized-bed gasification method and a facility therefor capable of properly causing a bed material to pass every corner of a fluidized-bed gasification furnace even if the gasification furnace is large-sized, and capable of simplifying the fluidized-bed gasification furnace. 
     Solution to Problems 
     The invention is directed to a fluidized-bed gasification method arranging a fluidized-bed combustion furnace where char is burned to heat a bed material, hot fluid from said fluidized-bed combustion furnace being separated by a separator into the bed material and an exhaust gas, the separated bed material being introduced through a downcomer into a fluidized-bed gasification furnace, a raw material being introduced into said fluidized-bed gasification furnace where the raw material is gasified in a fluidized bed fed with a gasifying agent and a resultant produced gas is taken out, char produced upon the gasification of the raw material and the bed material being circulated to said fluidized-bed combustion furnace to burn the char, said method comprising supplying the bed material from said downcomer to a dispersion section extending along a width of a bed-material-introduction-side wall of the fluidized-bed gasification furnace, blowing a fluidizing gas into the dispersion section to fluidize the bed material, and supplying the bed material in the dispersion section into the fluidized-bed gasification furnace substantially evenly throughout the width on a bed-material-introduction side. 
     The invention is directed to a fluidized-bed gasification facility comprising a fluidized-bed combustion furnace where char is burned to heat a bed material, a separator for separation of hot fluid from said fluidized-bed combustion furnace into the bed material and an exhaust gas, a fluidized-bed gasification furnace into which the bed material separated in said separator is introduced via a downcomer, into which raw material is introduced and where the raw material is gasified by a fluidized bed fed with a gasifying agent and a produced gas is taken out, a circulation passage for circulation of char produced upon the gasification of the raw material in said fluidized-bed gasification furnace and the bed material to the fluidized-bed combustion furnace, a dispersion section extending along width of a bed-material-introduction-side wall constituting one of side surfaces of said fluidized-bed gasification furnace to receive the bed material from said downcomer, fluidizing-gas introduction means for blowing a fluidizing gas into said dispersion section to fluidize the bed material in the dispersion section, and a supply section for supplying the bed material in said dispersion section into the fluidized-bed gasification furnace substantially evenly throughout the width on a bed-material-introduction side. 
     In the fluidized-bed gasification facility of the invention, said circulation passage is arranged on a bed-material-lead-out-side wall of the fluidized-bed gasification furnace opposing to the bed-material-introduction-side wall. 
     In the fluidized-bed gasification facility of the invention, said supply section may comprise a plurality of supply pipes arranged along the width of the bed-material-introduction-side wall and leading from the dispersion section to the fluidized-bed gasification furnace. 
     In the fluidized-bed gasification facility of the invention, said supply section may comprise a supply passage having a supply port extending along the width of the bed-material-introduction-side wall and leading from the dispersion section to the fluidized-bed gasification furnace. 
     In the fluidized-bed gasification facility of the invention, said fluidizing-gas introduction means may comprise a plurality of fluidizing gas introduction pipes arranged along length of the dispersion section. 
     In the fluidized-bed gasification facility of the invention, said downcomer may have a lower opening positioned in the bed material in the dispersion section so as to prevent burnt gas from flowing back from the dispersion section to the downcomer. 
     In the fluidized-bed gasification facility of the invention, said supply pipe may comprise an inlet portion extending downwardly from the dispersion section, an intermediate portion for changing an extensional direction from the inlet portion to accumulate the bed material for formation of a sealing zone for pressure and an outlet portion leading from the intermediate portion to the fluidized-bed gasification furnace so as to supply the bed material overflowed from said intermediate portion to the fluidized-bed gasification furnace, said sealing zone being configured to prevent burnt gas from flowing back from the fluidized-bed gasification furnace to the dispersion section. 
     In the fluidized-bed gasification facility of the invention, said downcomer may comprise an intermediate portion for changing an extension in direction from the separator to accumulate the bed material for formation of a sealing zone for pressure and an outlet portion leading from the changing portion to the dispersion section to supply the bed material overflowed from said intermediate portion to the dispersion section, said sealing zone being configured to prevent the burnt gas from flowing back from the dispersion section to over the downcomer. 
     In the fluidized-bed gasification facility of the invention, a communication section is arranged between said dispersion section and said supply passage to provide a flow passage with a width substantially same as that of the bed-material-introduction-side wall and leading from the dispersion section to the supply passage, said communicating section being formed by changing the extension in direction from the dispersion section to accumulate the bed material between the dispersion section and the supply passage for formation of a sealing zone for pressure, said sealing zone being configured to prevent the burnt gas from flowing back from the fluidized-bed gasification furnace to the dispersion section. 
     In the fluidized-bed gasification facility of the invention, the configuration may be such that the raw material is introduced into the fluidized-bed gasification furnace at plural positions. 
     When the bed material is to be supplied from said separator to the fluidized-bed gasification furnace, the bed material is introduced through said downcomer into the dispersion section extending along the width of the bed-material-introduction-side wall of the fluidized-bed gasification furnace, blowing a fluidizing gas from the fluidizing-gas introduction means into the dispersion section, fluidizing the bed material to evenly disperse the same in the dispersion section, supplying the bed material from said dispersion section to the fluidized-bed gasification furnace substantially evenly throughout the width on a bed-material-introduction side while reducing the lingering of the bed material in said fluidized-bed gasification furnace. 
     Advantageous Effects of Invention 
     According to a fluidized-bed gasification method and a facility therefor of the invention, the bed material is supplied into said fluidized-bed gasification furnace substantially evenly throughout the width on the bed-material-introduction side so that, even if said fluidized-bed gasification furnace is large sized, the bed material can be caused to pass every corner of the fluidized-bed gasification furnace, thereby attaining a desired gasification amount and preventing unreacted char from being discharged. Since the bed material is caused to pass substantially evenly in said fluidized-bed gasification furnace, it becomes unnecessary to provide a heat-resistant partition or partitions or the like in the fluidized-bed gasification furnace, which advantageously simplifies in structure the fluidized-bed gasification furnace and reduces a production cost. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a side view showing a conventional fluidized-bed gasification facility; 
         FIG. 2  is a side view showing a further conventional fluidized-bed gasification facility; 
         FIG. 3  is a plan view of  FIG. 2 ; 
         FIG. 4  is a side view showing a still further conventional fluidized-bed gasification facility; 
         FIG. 5  is a plan view of  FIG. 4 ; 
         FIG. 6  is a side view showing a first embodiment of the invention; 
         FIG. 7  is a schematic view showing flows of bed material and of fluidizing gas in the first embodiment of the invention; 
         FIG. 8  is a schematic view showing a dispersion section provided with fluidizing gas introduction pipe and a wind box; 
         FIG. 9  is a schematic view showing fluidizing-gas introduction means in the dispersion section; 
         FIG. 10  is a schematic view showing blowout of the fluidizing gas from an introduction portion; 
         FIG. 11  is a schematic view showing flows of bed material and of fluidizing gas in a second embodiment of the invention; 
         FIG. 12  is a schematic view showing flows of bed material and fluidizing gas in a third embodiment of the invention; 
         FIG. 13  is a schematic view showing flows of bed material and fluidizing gas in a fourth embodiment of the invention; and 
         FIG. 14  is a schematic view showing introduction of raw material into a fluidized-bed gasification furnace at plural positions in a fifth embodiment of the invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A first embodiment of the invention will be described in conjunction with  FIGS. 6 and 7 . 
     Provided in the first embodiment are a fluidized-bed combustion furnace  1  in which char is burned to heat a bed material, a separator  8  in which the bed material  11  is separated from hot fluid from the combustion furnace  1  and a fluidized-bed gasification furnace  40  into which the bed material  11  separated in the separator  8  is introduced through a downcomer  46 , into which a raw material  26  is introduced from a raw material feeder (not shown) in a raw material introduction section and to which a gasifying agent such as steam, air or carbon dioxide is supplied to form a fluidized bed  16 . In the fluidized-bed gasification furnace  40 , the raw material  26  is gasified by agitating the same with the hot bed material  11  and produced gas  20  is taken out through a produced gas takeout section (not shown). Char produced upon the gasification of the raw material in the gasification furnace  40  and the bed material  11  are circulated through a circulation passage  25  to the fluidized-bed combustion furnace  1 . In the above, introduction of the raw material  26  into the fluidized-bed gasification furnace  40  is conducted upstream of the flow of the bed material to increase a reaction time of the raw material  26 . 
     The fluidized-bed gasification furnace  40  has walls  41  and  42  away from and near the fluidized-bed combustion furnace  1  and serving as a bed-material-introduction-side wall through which the bed material  11  is introduced and as a bed-material-lead-out-side wall through which the bed material  11  is led out, respectively. Arranged above and adjacent to the bed-material-introduction-side wall  41  of the fluidized-bed gasification furnace  40  is a cylindrical dispersion section  43  extending along and having a length substantially same as a width of the wall  41 . The dispersion section  43  is not restricted to a cylinder and may have a square or other three-dimensional shape. 
     The dispersion section  43  is internally partitioned by a partition  44  into an upper space for temporary storage of the bed material  11  from the downcomer  46  and a lower space serving as a wind box  45 . The dispersion section  43  has a top connected to the downcomer  46  at a position centrally of the length of the section  43 , a bottom having fluidizing-gas introduction means  47  arranged for introduction of fluidizing gas such as nitrogen, carbon dioxide or steam into the section  43  at plural positions, and a periphery with a supply section  48  connected to the fluidized-bed gasification furnace  40 . 
     The downcomer  46  comprises a slant pipe  49  extending downwardly aslant from the separator  8  and connected to the dispersion section  43 . A lower opening  50  of the downcomer  46  is positioned in the bed material  11  in the dispersion section  43  to form a sealing zone for breaking off a pressure relationship. 
     The fluidizing-gas introduction means  47  comprises, as shown in  FIGS. 8 and 9 , a plurality of fluidizing-gas introduction pipes  51  arranged on and along the length of the dispersion section  43  (the width of the bed-material-introduction-side wall  41 ) and spaced apart from each other by a constant spacing L of several to scores of centimeters. The partition  44  in the dispersion section  43  is provided with, as shown in  FIG. 9 , concave introduction sections  53  peripherally formed with fluidizing-gas introduction ports  52 . The introduction ports  52  on the introduction sections  53  may be aslant downward from within to outside as shown in  FIG. 10 . Each of the fluidizing-gas introduction pipes  51  may be provided with, as shown in  FIG. 8 , a pressure gage or other sensor means  54  and an on/off valve or other on/off means  55  selectively opened and closed depending on data from the sensor means  54  to regulate a fluidized state of the bed material  11 . 
     The supply section  48  comprises a plurality of supply pipes  56  arranged on the periphery of the dispersion section  43  on a side near the fluidized-bed gasification furnace  40  along the length of the section  43  and spaced apart from each other by a constant spacing of scores of centimeters to several meters. The plural supply pipes  56  extend downwardly from the dispersion section  43  and are connected to the fluidized-bed gasification furnace  40  with a predetermined spacing from each other along and throughout the width of the bed-material-introduction-side wall  41  of the furnace  40 . 
     The supply means for supplying the coal or other raw material  26  to the fluidized-bed gasification furnace  40  may be such that a raw material supply pipe or pipes (not shown) extending from the raw material feeder or the like is or are connected to the dispersion section  43  at a position or positions so as to supply the raw material  26  to the section  43 . 
     Further, a circulation passage  25  leading from the fluidized-bed gasification furnace  40  to the fluidized-bed combustion furnace  1  is arranged on the bed-material-lead-out-side wall  42  of the furnace  40  opposing to the bed-material-introduction-side wall  41 . 
     An operation of the first embodiment for the fluidized-bed gasification method and the facility therefor of the invention will be described. 
     When the bed material  11  is to be supplied from the separator  8  to the fluidized-bed gasification furnace  40 , the bed material  11  is introduced through the downcomer  46  into the dispersion section  43  extending along the width of the bed-material-introduction-side wall  41  of the furnace  40 . The fluidizing gas is blown from the fluidizing-gas introduction means  47  into the dispersion section  43  to fluidize and disperse evenly the bed material  11  into the dispersion section  43  without localized distribution of the bed material  11  due to a charged position from the downcomer  46 . Then, the bed material  11  is supplied from the dispersion section  43  via the plural supply pipes of the supply section  48  to the fluidized-bed gasification furnace  40  evenly throughout the width on the bed-material-introduction side, thereby leading out the bed material  11  from the bed-material-lead-out side in the furnace  40  while reducing the lingering of the bed material  11  in the furnace  40 . 
     Thus, according to the first embodiment of the fluidized-bed gasification method and the facility therefor, the bed material  11  is supplied to the fluidized-bed gasification furnace  40  evenly throughout the width on the fluidized-bed-introduction side, so that even if the gasification furnace  40  is larger-sized, the bed material  11  can be caused to pass every corner of the fluidized-bed gasification furnace  40 , thereby attaining a desired gasification amount and preventing unreacted char from being discharged. Since the bed material  11  is caused to pass evenly in the fluidized-bed gasification furnace  40 , it becomes unnecessary to provide a heat-resistant partition, partitions or the like in the fluidized-bed gasification furnace  40 , which simplifies in structure the fluidized-bed gasification furnace  40 , reduces a production cost and facilitates maintenance. 
     The dispersion section  43 , which extends along and has the length substantially equal to the width of the bed-material-introduction-side wall  41  of the fluidized-bed gasification furnace  40 , facilitates the supply of the bed material  11  evenly into the gasification furnace  40  throughout the width on the bed-material-introduction side, so that the bed material  11  can be caused to pass every corner of the gasification furnace  40 , thereby properly attaining a desired gasification amount and easily preventing the unreacted char from being discharged. 
     The circulation passage  25 , which is arranged on the bed-material-lead-out-side wall  42  of the fluidized-bed gasification furnace  40  opposite to the bed-material-introduction-side wall  41 , facilitates the supply of the bed material  11  evenly into the gasification furnace  40  throughout the width on the bed-material-introduction side, so that the bed material  11  can be caused to pass every corner of the gasification furnace  40 , thereby properly attaining a desired gasification amount and easily preventing the unreacted char from being discharged. 
     The supply section  48 , which comprises the plural supply pipes  56  leading from the dispersion section  43  to the fluidized-bed gasification furnace  40  and arranged along the width of the bed-material-introduction-side wall  41 , further facilitates the supply of the bed material  11  evenly into the gasification furnace  40  throughout the width on the bed-material-introduction side, so that the bed material  11  can be caused to pass every corner of the gasification furnace  40 , thereby properly attaining a desired gasification amount and easily preventing the unreacted char from being discharged. 
     The fluidizing-gas introduction means  47 , which comprises the plural fluidizing-gas introduction pipes  51  arranged along the length of the dispersion section  43  to blow the fluidizing gas into the dispersion section  43  and evenly disperse the same in the section  43  without localized dispersion due to the charged position of the bed material  11  from the downcomer  46 , further facilitates the supply of the bed material  11  evenly into the fluidized-bed gasification furnace  40  throughout the width on the bed-material-introduction side, so that the bed material  11  can be caused to pass every corner of the fluidized-bed gasification furnace  40 , thereby properly attaining a desired gasification amount and easily preventing the unreacted char from being discharged. 
     The downcomer  46 , which has the lower opening  50  positioned in the bed material  11  in the dispersion section  43  for prevention of the burnt gas from flowing back from the dispersion section  43  to the downcomer  46 , optimally supplies the bed material  11  from the dispersion section  43  through the supply pipes  56  to the fluidized-bed gasification furnace  40 , so that the bed material  11  can be caused to pass every corner of the fluidized-bed gasification furnace  40 , thereby properly attaining a desired gasification amount and easily preventing the unreacted char from being discharged. 
     A second embodiment of the invention will be described in conjunction with  FIG. 11  where parts similar to those in  FIGS. 6 and 7  are represented by the same reference numerals. 
     The second embodiment has a modification of the supply section  48  in the first embodiment. Specifically, a supply section  60  of the second embodiment comprises a plurality of supply pipes  61  arranged on a periphery of a dispersion section  43  on a side near a fluidized-bed gasification furnace  40  along a length of the section  43  (a width of a bed-material-introduction-side wall  41  of the furnace  40 ) and spaced apart from each other by a constant spacing of scores of centimeters to several meters; each of the supply pipes  61  comprises an inlet portion  62  extending downwardly from the dispersion section  43 , a bottom intermediate portion  63  extending substantially horizontally from a lower end of the inlet portion  62  for change of an extension in direction from the inlet portion  62 , a rising intermediate portion  64  extending upward from a tip of the bottom intermediate portion  63  and an outlet portion  65  extending from an upper end of the rising intermediate portion  64  to the gasification furnace  40 , a bed material  11  being accumulated in the portions  62 ,  63  and  64  to form a sealing zone for pressure and being consistently fluidized by introducing fluidizing gas such as nitrogen, carbon dioxide or steam into the sealing zone. The plural supply pipes  61  are arranged with a predetermined spacing along the width of a bed-material-introduction-side wall  41  throughout the width on a bed-material-introduction side in the fluidized-bed gasification furnace  40 . The inlet and intermediate portions  62 ,  63  and  64  may be of any shape, providing the sealing zone for pressure is formed. 
     The dispersion section  43  is of a shape substantially similar to that of the first embodiment and is internally partitioned by a partition  44  (see  FIG. 8 ) into an upper space for temporary storage of a bed material  11  from a downcomer  46  and a lower space serving as a wind box  45 . The dispersion section  43  has a top connected to the downcomer  46  at a position centrally of the length of the section  43  and a bottom having fluidizing-gas introduction means  47  arranged for introduction of the fluidizing gas such as nitrogen, carbon dioxide or steam into the section  43  at plural positions. 
     The downcomer  46  comprises a slant pipe  49  extending downward aslant from the separator  8  and connected to the dispersion section  43 . A lower opening (not shown) of the downcomer  46  is positioned in the dispersion section  43  above the bed material  11 . 
     Substantially like the first embodiment, the fluidizing-gas introduction means  47  comprises a plurality of fluidizing gas introduction pipes  51  arranged on and along the length of the dispersion section  43  and spaced apart from each other by a constant spacing L of several to scores of centimeters. As shown in  FIGS. 8-10 , the partition  44  in the dispersion section  43  is provided with concave introduction sections  53  peripherally formed with fluidizing-gas introduction ports  52 . The introduction ports  52  on the introduction section  53  may be aslant downward from within to outside. Each of the fluidizing-gas introduction pipes  51  may be provided with a pressure gage or other sensor means  54  and an on/off valve or other on/off means  55  selectively opened and closed depending on data from the sensor means  54  to regulate a fluidized state of the bed material  11 . 
     Supply means for supplying the raw material  26  such as coal into the fluidized-bed gasification furnace  40  may be such that a raw material supply pipe or pipes (not shown) extending from a raw material feeder or the like is or are connected to the dispersion section  43  so as to supply the raw material  26  to the section  43 . 
     Further, a circulation passage  25  (see  FIG. 6 ) leading from the fluidized-bed gasification furnace  40  to the fluidized-bed combustion furnace  1  is arranged on the bed-material-lead-out-side wall  42  of the furnace  40  opposing to the bed-material-introduction-side wall  41 . 
     An operation of the second embodiment for the fluidized-bed gasification method and the facility therefor of the invention will be described. 
     When the bed material  11  is to be supplied from the separator  8  to the fluidized-bed gasification furnace  40 , the bed material  11  is introduced through the downcomer  46  into the dispersion section  43  extending along the width of the bed-material-introduction-side wall  41  of the furnace  40 . The fluidizing gas is blown from the fluidizing-gas introduction means  47  into the dispersion section  43  to evenly disperse the bed material  11  into the dispersion section  43  without localized distribution of the bed material  11  due to a charged position from the downcomer  46 . Then, the bed material  11  is supplied from the dispersion section  43  via the plural supply pipes of the supply section  60  to the fluidized-bed gasification furnace  40  evenly throughout the width on the bed-material-introduction side, thereby leading out the bed material  11  from the bed-material-lead-out side of the furnace  40  while reducing the lingering of the bed material  11  in the furnace  40 . 
     In this case, in the supply section  60 , the bed material  11  is accumulated in the inlet and intermediate portions  62 ,  63  and  64  to form a sealing zone for pressure so as to prevent the burnt gas in the fluidized-bed gasification furnace  40  from flowing back into the dispersion section  43 , the bed material  11  overflowed from the rising intermediate portion  64  being supplied via the outlet portion  65  to the furnace  40 . 
     Thus, the second embodiment of the fluidized-bed gasification method and the facility therefor of the invention can exhibit effects and advantages substantially similar to those in the first embodiment. With the supply pipes  61  of the supply section  60  comprising the inlet portion  62  extending downward from the dispersion section  43 , the intermediate portions  63  and  64  for change of an extension in direction of the inlet portion  62  to accumulate the bed material  11  for formation of a sealing zone for pressure and the outlet portion  65  leading from the intermediate portion  64  to the fluidized-bed gasification furnace  40  for supply of the bed material  11  overflowed from the rising intermediate portion  64  to the furnace  40 , the sealing zone serving to prevent the burnt gas in the furnace  40  from flowing back into the dispersion section  43 , the bed material  11  is optimally supplied from the dispersion section  43  via the supply pipes  61  to the furnace  40  and the bed material  11  can be caused to pass every corner of the furnace  40 , thereby properly attaining a desired gasification amount and easily preventing the unreacted char from being discharged. 
     Next, a third embodiment of the invention will be described in conjunction with  FIG. 12  where parts similar to those in  FIGS. 6 and 7  are represented by the same reference numerals. 
     The third embodiment has a modification of the downcomer  46  in the first embodiment. Specifically, a downcomer  70  of the third embodiment comprises a slant pipe  71  extending aslant downward from the separator  8 , a lowering intermediate portion  72  extending substantially vertically from a lower end of the slant pipe  71 , a bottom intermediate portion  73  extending substantially horizontally from a lower end of the lowering intermediate portion  72 , a rising intermediate portion  74  extending upward from a tip end of the bottom intermediate portion  73  and an outlet portion  75  extending from an upper end of the rising intermediate portion  74  and leading to the dispersion section  43 , the bed material  11  being accumulated in the intermediate portions  72 ,  73  and  74  to form a sealing zone for pressure, the bed material  11  in the intermediate portions being consistently fluidized by introducing fluidizing gas such as nitrogen, carbon dioxide or steam into the sealing zone. The intermediate portions  72 ,  73  and  74  may be of any shape, providing the sealing zone for pressure is formed. 
     The dispersion section  43  is of a shape substantially similar to that of the first embodiment and is internally partitioned by a partition  44  (see  FIG. 8 ) into an upper space for temporary storage of the bed material  11  supplied from a downcomer  46  to the fluidized-bed gasification furnace  40  and a lower space serving as a wind box  45 . The dispersion section  43  has a bottom having fluidizing-gas introduction means  47  arranged for introduction of the fluidizing gas into the section  43  at a plurality of positions and a periphery with a supply section  48  connected to the fluidized-bed gasification furnace  40 . 
     Substantially like the first embodiment, the fluidizing-gas introduction means  47  comprises a plurality of fluidizing gas introduction pipes  51  arranged on and along the length of the dispersion section  43  (the width of the bed-material-introduction-side wall  41 ) and spaced apart from each other by a constant spacing L from several to scores of centimeters. As shown in  FIGS. 8-10 , a partition  44  in the dispersion section  43  is provided with concave introduction sections  53  peripherally formed with introduction ports  52  for the fluidizing gas. The introduction ports  52  on the introduction section  53  may be aslant downward from within to outside. Each of the fluidizing gas introduction pipes  51  may be provided with a pressure gage or other sensor means  54  and an on/off valve or other on/off means selectively opened and closed depending upon data from the sensor means  54  to regulate a fluidized state of the bed material  11 . 
     Substantially similar to the first embodiment, the supply section  48  comprises a plurality of supply pipes  56  arranged on a periphery of the dispersion section  43  on a side near the fluidized-bed gasification furnace  40  and spaced apart from each other by a constant spacing from scores of centimeters to several meters along the length of the section  43 . The plural supply pipes  56  extend downward from the dispersion section  43 , are connected to the fluidized-bed gasification furnace  40  and are spaced by a predetermined spacing along the width of the bed-material-introduction-side wall  41  throughout the width of the bed-material-introduction-side of the furnace  40 . 
     The supply means for supplying the coal or other raw material  26  into the fluidized-bed gasification furnace  40  may be such that a raw material supply pipe or pipes (not shown) extending from a raw material feeder or the like is or are connected to the dispersion section  43  so as to supply the raw material  26  to the section  43 . 
     Further a circulation passage  25  (see  FIG. 6 ) leading from the fluidized-bed gasification furnace  40  to the fluidized-bed combustion furnace  1  is arranged on the bed-material-lead-out-side wall  42  of the furnace  40  opposing to the bed-material-introduction-side wall  41 . 
     An operation of the third embodiment for the fluidized-bed gasification method and the facility therefor of the invention will be described. 
     When the bed material  11  is to be supplied from the separator  8  to the fluidized-bed gasification furnace  40 , the bed material is introduced through the downcomer  70  into the dispersion section  43  extending along the width of the bed-material-introduction-side wall  41  of the furnace  40 . The fluidizing gas is blown from the fluidizing-gas introduction means  47  into the dispersion section  43  to evenly disperse the bed material  11  in the section  43  without localized distribution of the bed material  11  due to a charged position from the downcomer  46 . Then, the bed material  11  is supplied from the dispersion section  43  via the plural supply pipes of the supply section  48  into the fluidized-bed gasification furnace  40  evenly throughout the width on the bed-material-introduction side, thereby leading out the bed material  11  from the bed-material-lead-out side of the furnace  40  while reducing the lingering of the bed material  11  in the furnace  40 . 
     In this case, in the downcomer  70 , the bed material  11  is accumulated in the intermediate portions  72 ,  73  and  74  to form a sealing zone for pressure to prevent the burnt gas in the dispersion section  43  from flowing back over the downcomer  70 , the bed material  11  overflowed from the rising intermediate portion  74  being supplied through the outlet portion  75  to the dispersion section  43 . 
     Thus, the fluidized-bed gasification method and the facility therefor according to the third embodiment of the invention can exhibit effects and advantages substantially similar to those in the first embodiment. With the downcomer  70  comprising the intermediate portions  72 ,  73  and  74  for accumulation of the bed material  11  to form a sealing zone for pressure through change of an extension in direction of the separator  8  and an outlet portion  75  leading from the intermediate portion  74  to the dispersion section  43  to properly supply the bed material  11  overflowed from the intermediate portion to the section  43 , the sealing zone serving to prevent the burnt gas in the dispersion section  43  from flowing back to over the downcomer  70 , the bed material  11  is optimally supplied from the dispersion section  43  via the supply pipes  72 ,  73  and  74  and the outlet portion  75  to the furnace  40  and the bed material  11  can be caused to pass every corner of the fluidized-bed gasification furnace  40 , thereby properly attaining a desired gasification amount and easily preventing the unreacted char from being discharged. 
     Next, a fourth embodiment of the invention will be described in conjunction with  FIG. 13  where parts similar to those in  FIGS. 6 and 7  are represented by the same reference numerals. 
     The fourth embodiment has a modification in shape of the dispersion and supply sections  43  and  48  of the first embodiment. Specifically, a dispersion section  80  of the fourth embodiment comprises a rectangular-parallelepiped passage  81  extending along the width of the bed-material-introduction-side wall  41  of the fluidized-bed gasification furnace  40  and directed downward from a vicinity above the bed-material-introduction-side wall  41 . A supply section  82  of the fourth embodiment comprises a supply passage  84  between the dispersion section  80  and the fluidized-bed gasification furnace  40 , having a supply port  83  extending along the width of the bed-material-introduction-side wall  41  to provide a supply passage  84  leading from above to the furnace  40 . Arranged between the dispersion section  80  and the supply section  82  are a bottom communicating section  85  extending substantially horizontally from a lower end of the dispersion section  80  and a rising communicating section  86  extending upward from a tip of the bottom communicating section  85  to an upper end of the supply passage  84  of the supply section  82  to thereby provide a flow passage from the passage  81  of the dispersion section  80  to the supply passage  84  of the supply section  82  and with a width same as that of the bed-material-introduction-side wall  41 . The bed material  11  is accumulated in a lower portion of the dispersion section  80  and the communicating sections  85  and  86  to form a sealing zone for pressure. The communicating sections  85  and  86  may be of any shape, providing the sealing zone for pressure is formed. 
     Arranged on the lower end of the dispersion section  80  are fluidizing-gas introduction means  47  for introduction of fluidizing gas into the sections  80 ,  85  and  86  at plural positions. The fluidizing-gas introduction means  47  comprises a plurality of fluidizing-gas introduction pipes  51  arranged along the length of the dispersion section  80  (the width of the bed-material-introduction-side wall  41 ) and spaced apart from each other by a constant spacing L of several to scores of centimeters to consistently fluidize the bed material  11  in the sections  80 ,  85  and  86 . When the lower portion of the dispersion section  80  and the bottom communicating sections  85  and  86  are partitioned by a partition (not shown) to provide a wind box (not shown), the partition may be provided with, as shown in  FIGS. 8-10 , concave introduction sections  53  peripherally formed with fluidizing-gas introduction ports  52 . The introduction ports  52  on the introduction section  53  may be aslant downward from within to outside. Each of the fluidizing-gas introduction pipes  51  may be provided with a pressure gage or other sensor means  54  and an on/off valve or other on/off means selectively opened and closed depending on data from the sensor means  54  to regulate a fluidized state of the bed material  11 . 
     Supply means for supplying coal or other raw material  26  to the fluidized-bed gasification furnace  40  is seen in  FIG. 6  with respect to the first to third embodiments; in the fourth embodiment, supply means is such that a raw material supply pipe or pipes (not shown) extending from a raw material feeder or the like and connected to the section  80 ,  85  or  86  at one or more positions so as to supply the raw material to the sealing zone of the sections  80 ,  85  and  86 . 
     Further, a circulation passage  25  (see  FIG. 6 ) leading from the fluidized-bed gasification furnace  40  to the fluidized-bed combustion furnace  1  is arranged on the bed-material-lead-out-side wall  42  of the furnace  40  opposing to the bed-material-introduction-side wall  41 . 
     An operation of the fourth embodiment for the fluidized-bed gasification method and the facility therefor of the invention will be described. 
     When the bed material  11  is to be supplied from the separator  8  to the fluidized-bed gasification furnace  40 , the bed material  11  is introduced through the downcomer  46  into the dispersion section  80  extending along the width of the bed-material-introduction-side wall  41  of the furnace  40 . The fluidizing gas is blown from the fluidizing-gas introduction means  47  into a lower end of the dispersion section  80  to evenly disperse the bed material  11  in the dispersion and communicating sections  80 ,  85  and  86  without localized distribution of the bed material  11  due to a charged position from the downcomer  46 . Then, the bed material  11  is supplied from the rising communicating section  86  via the supply passage  84  to the fluidized-bed gasification furnace  40  evenly throughout the with on the bed-material-introduction side, thereby leading out the bed material  11  from the bed-material-lead-out-side of the furnace  40  while reducing the lingering of the bed material  11  in the furnace  40 . 
     In this case, the bed material  11  is accumulated in the dispersion and communicating sections  80 ,  85  and  86  to form a sealing zone for pressure so as to prevent the burnt gas in the fluidized-bed gasification furnace  40  from flowing back to over the dispersion section  80 , the bed material  11  overflowed from the rising communicating section  86  being supplied via the supply passage  84  to the furnace  40 . 
     Thus, the fluidized-bed gasification method and the facility therefor according to the fourth embodiment of the invention can exhibit effects and advantages substantially similar to those of the first embodiment. The supply section  82 , which comprises the supply passage  84  with the supply port  83  extending along the width of the bed-material-introduction-side wall  41  and leads from the passage  81  of the dispersion section  80  to the fluidized-bed gasification furnace  40 , further facilitates the supply of the bed material  11  to the furnace  40  evenly throughout the width on the bed-material-introduction side, so that the bed material  11  can be caused to pass every corner of the fluidized-bed gasification furnace  40 , thereby properly attaining a desired gasification amount and easily preventing the unreacted char from being discharged. 
     Further, the communicating sections  85  and  86  are arranged between the dispersion section  80  and the supply passage  84  to provide the flow passage from the passage  81  of the dispersion section  80  to the supply passage  84  and having the width same at that of the bed-material-introduction-side wall  41 . The communicating sections  85  and  86  are formed by changing the extension in direction of the dispersion section  80  to accumulate the bed material  11  between the passage  81  of the dispersion section  80  and the supply passage  84  to thereby form a sealing zone for pressure so as to prevent the burnt gas from flowing back from the fluidized-bed gasification furnace  40  to over the dispersion section  80 . Thus, the bed material  11  can be favorably supplied from the passage  81  of the dispersion section  80  via the communicating sections  85  and  86  and the supply passage  84  of the supply section  82  to the fluidized-bed gasification furnace  40  to cause the bed material  11  to pass any corner of the fluidized-bed gasification furnace  40 , thereby properly attaining a desired gasification amount and easily preventing unreacted char from being discharged. 
     A fifth embodiment of the invention will be described in conjunction with  FIG. 14  in which parts similar to those in  FIG. 13  are represented by the same reference numerals. 
     The fifth embodiment has a modification of coal or other raw material supply means shown in the fourth embodiment. Specifically, raw material supply means  90  comprises raw material supply pipes  91  arranged along width of a bed-material-introduction-side wall  41  and spaced by a constant spacing. A raw material is introduced by a raw material feeder or the like (not shown) through the raw material supply pipes  91  into a fluidized-bed gasification furnace  40  upstream of the flow of bed material to increase a reaction time of the raw material. The raw material supply means shown in the fifth embodiment may apply to any of the first to third embodiments. 
     Further, the fifth embodiment has a dispersion section  80 , communicating sections  85  and  86 , a supply section  82 , fluidizing-gas introduction means  47  and a circulation passage  25  substantially similar to those of the fourth embodiment. 
     An operation of the fifth embodiment for the fluidized-bed gasification method and the facility therefor of the invention will be described. 
     When the bed material  11  is to be supplied from the separator  8  to the fluidized-bed gasification furnace  40 , like the fourth embodiment, the bed material  11  is introduced through the downcomer  46  into the dispersion section  80  extending along the width of the bed-material-introduction-side wall  41  of the furnace  40 . The fluidizing gas is blown from the fluidizing-gas introduction means  47  into the lower end of the dispersion section  80  to evenly disperse the bed material  11  into the dispersion and communicating sections  80 ,  85  and  86  without localized distribution of the bed material  11  due to a charged position from the downcomer  46 . Then, the bed material  11  is supplied from the rising communicating section  86  via the supply passage  84  of the supply section  82  to the fluidized-bed gasification furnace  40  evenly throughout the width on the bed-material-introduction side, thereby leading out the bed material from the bed-material-lead-out side of the fluidized-bed gasification furnace  40  while reducing the lingering of the bed material  11  in the furnace  40 . 
     The raw material supply means  90  concurrently supplies the coal or other raw material through the plural raw material supply pipes  91  into the fluidized-bed gasification furnace  40  at plural positions. 
     Thus, the fluidized-bed gasification method and the facility therefor according to the fifth embodiment can attain effects and advantages substantially similar to those in the fourth embodiment. When the construction is such that the raw material is introduced into the fluidized-bed gasification furnace  40  at plural positions, the raw material can be introduced in a dispersed manner into the fluidized-bed gasification furnace  40 , so that a desired gasification amount can be properly attained and the unreacted char can be easily prevented from being discharged. 
     It is to be understood that a fluidized-bed gasification method and a facility therefor according to the invention are not limited to the above embodiments and that various changes and modifications may be made without departing from the scope of the invention. For example, any other shape and construction may be employed, providing the bed material is supplied to the fluidized-bed gasification furnace evenly throughout the width on the bed-material-introduction side. A plurality of downcomers may be provided to supply the bed material to the dispersion section. 
     REFERENCE SIGNS LIST 
     
         
         
           
               1  fluidized-bed combustion furnace 
               8  separator 
               11  bed material 
               25  circulation passage 
               26  raw material 
               40  fluidized-bed gasification furnace 
               41  bed-material-introduction-side wall 
               43  dispersion section 
               46  downcomer 
               47  fluidizing-gas introduction means 
               48  supply section 
               50  opening 
               51  fluidizing gas introduction pipe 
               56  supply pipe 
               60  supply section 
               61  supply pipe 
               62  inlet portion 
               63  bottom intermediate portion 
               64  rising intermediate portion 
               65  outlet portion 
               70  downcomer 
               72  lowering intermediate portion 
               73  bottom intermediate portion 
               74  rising intermediate portion 
               75  outlet portion 
               80  dispersion section 
               82  supply section 
               83  supply port 
               84  supply passage 
               85  bottom communicating section 
               86  rising communicating section