Apparatus for gasifying solid fuel

Abstract

The present invention provides a relatively small scale apparatus for gasifying solid fuel in which pyrolysis gas produced in a pyrolyzer by thermal-decomposition reaction of the solid fuel can be reformed to crude fuel gas. The apparatus comprises a solid fuel pyrolyzer 1 and a steam reformer 5, and thermally decomposes the solid fuel with a combustion reaction of a low oxygen density to produce the pyrolysis gas, and reforms the pyrolysis gas to produce the crude fuel gas. The pyrolyzer has an air inlet 18 positioned at a bottom part thereof and upwardly blowing combustion air into the pyrolyzer; a bed of pyrolyzer 30 located above the air inlet; and a pyrolysis gas exit positioned at an upper part of a body of the pyrolyzer and conducting the pyrolysis gas out of the pyrolyzer. The bed is made by a layered stack of many spherical heat-resistant materials 32 which form a number of narrow gaps for draft of the combustion air over the whole bed. The steam reformer has a reforming area 51 which produces the crude fuel gas by a steam reforming reaction of the pyrolysis gas, a pyrolysis gas inlet 55 which is in communication with the pyrolysis gas exit and which introduces the pyrolysis gas into the reforming area, a mixed gas inlet 54 introducing mixed gas of steam and air into the reforming area, a reformed gas effluent passage 70 for conducting reformed gas of the reforming area out of the reformer, and a permeable heat-barrier 60 positioned between the reforming area and the reformed gas effluent passage. The barrier is made by a layered stack of many spherical heat-resistant materials 62 which form a number of narrow gaps for draft of the pyrolysis gas and the mixed gas.

1 . An apparatus for gasifying solid fuel which thermally decomposes the solid fuel by a combustion reaction of a low oxygen density so as to produce pyrolysis gas, comprising a solid fuel pyrolyzer and a steam reformer; 
 wherein said pyrolyzer has an air inlet positioned at a bottom part thereof to blow combustion air into the pyrolyzer, a bed of the pyrolyzer located above the air inlet, and a pyrolysis gas exit positioned at an upper part of a body of the pyrolyzer and conducting the pyrolysis gas out of the pyrolyzer, the bed being constituted by a layered stack of many spherical heat-resistant materials which form a number of narrow gaps for draft of the combustion air over the whole bed; and    wherein said steam reformer has a reforming area for producing crude fuel gas by a steam reforming reaction of said pyrolysis gas, a pyrolysis gas inlet which is in communication with said pyrolysis gas exit and which introduces the pyrolysis gas into the reforming area, a mixed gas inlet for introducing mixed gas of steam and air into the reforming area, a reformed gas effluent passage for conducting reformed gas of the reforming area out of the reformer, and a permeable heat-barrier positioned between the reforming area and the reformed gas effluent passage, the barrier being constituted by a layered stack of many spherical heat-resistant materials which form a number of narrow gaps for draft of said pyrolysis gas and said mixed gas.    
     
     
         2 . An apparatus for gasifying solid fuel as defined in  claim 1 , wherein a temperature of said combustion air is set to be a temperature equal to or higher than 150° C.  
     
     
         3 . An apparatus for gasifying solid fuel as in  claim 1  or  2 , wherein a temperature of said mixed gas is set to be a temperature equal to or higher than 300° C.  
     
     
         4 . An apparatus for gasifying fixed fuel as defined in one of  claims 1  to  3 , wherein said reformed gas effluent passage is connected with a heat exchanger for heating the combustion air, so that the reformed gas exchanges heat with the combustion air so as to be cooled down.  
     
     
         5 . A pyrolyzer of an apparatus for gasifying solid fuel which thermally decomposes the solid fuel by a combustion reaction of a low oxygen density so as to produce pyrolysis gas, comprising: 
 an air inlet positioned at a bottom part of the pyrolyzer and upwardly blowing combustion air into the pyrolyzer; a bed of the pyrolyzer located above the air inlet; and a pyrolysis gas exit positioned at an upper part of a body of the pyrolyzer and conducting the pyrolysis gas out of the pyrolyzer, the bed being constituted by a layered stack of many spherical heat-resistant materials, which form a number of narrow gaps for draft of the combustion air over the whole bed.    
     
     
         6 . A pyrolyzer for solid fuel as defined in  claim 5 , wherein said heat-resistant material is a solid and spherical ceramic form or metallic form having a diameter ranging from 5 mm to 200 mm.  
     
     
         7 . A steam reformer of an apparatus for gasifying solid fuel which reforms pyrolysis gas produced by a thermal-decomposition reaction of the solid fuel, comprising: 
 a reforming area which produces crude fuel gas by a steam reforming reaction of said pyrolysis gas; a pyrolysis gas inlet which introduces the pyrolysis gas of the solid fuel pyrolyzer into the reforming area; a mixed gas inlet for introducing mixed gas of steam and air into the reforming area; a reformed gas effluent passage for conducting reformed gas of the reforming area out of the reformer; and a permeable heat-barrier positioned between the reforming area and the reformed gas effluent passage, the barrier being constituted by a layered stack of many spherical heat-resistant materials, which form a number of narrow gaps for draft of said pyrolysis gas and said mixed gas.    
     
     
         8 . A pyrolyzer for solid fuel as defined in  claim 7 , wherein said heat-resistant material is a solid and spherical ceramic form or metallic form having a diameter ranging from 5 mm to 200 mm.  
     
     
         9 . A steam reformer as defined in  claim 7  or  8 , composed of a vertical reformer vessel part ( 50 ) defining said reforming area and a reformed gas flowing part ( 70 ) for conducting said reformed gas to the reformed gas effluent passage, said mixed gas inlet ( 54 ) being formed at an upper portion of said vessel part and a downstream end of the mixed gas supply passage being connected to the mixed gas inlet.  
     
     
         10 . A steam reformer as defined in  claim 9 , wherein a support structure ( 61 ) supporting said spherical heat-resistant materials ( 62 ) is secured to a wall ( 52 ) of said vessel part, and a horizontal flow passage ( 71 ) of said reformed gas flowing part extends under said support structure, the horizontal flow passage continuing to a vertical flow passage ( 72 ) of the flowing part which is in communication with said reformed gas effluent passage.