Downdraft gasification system and method

Abstract

A gasifier configured to receive biomass, including: a pyroreactor defining a first end, a second end, and an interior lumen, the first end defining a biomass inlet, the second end defining a pyroreactor outlet; a reduction basket arranged proximal the pyroreactor outlet, the reduction basket including a closed end and a basket opening opposing the closed end; a set of air manifolds fluidly connected to the interior lumen of the pyroreactor through a set of air inlets arranged between the first and second ends, proximal the second end; and a gasifier housing enclosing the pyroreactor, reduction basket, and set of air manifolds within a housing lumen.

We claim: 
     
         1 . A gasifier configured to receive biomass, comprising:
 a pyroreactor defining a first end, a second end, and an interior lumen, the first end defining a biomass inlet, the second end defining a pyroreactor outlet;   a reduction basket arranged proximal the pyroreactor outlet, the reduction basket comprising a closed end and a basket opening opposing the closed end;   a set of air manifolds fluidly connected to the interior lumen of the pyroreactor through a set of air inlets arranged between the first and second ends, proximal the second end; and   a gasifier housing enclosing the pyroreactor, reduction basket, and set of air manifolds within a housing lumen.   
     
     
         2 . The gasifier of  claim 1 , wherein the air manifolds are fluidly connected to a gasifier housing exterior. 
     
     
         3 . The gasifier of  claim 1 , wherein the pyroreactor is thermally insulated. 
     
     
         4 . The gasifier of  claim 1 , wherein the pyroreactor further comprises a burner arranged within the interior lumen proximal the air inlets. 
     
     
         5 . The gasifier of  claim 1 , wherein the second end is tapered toward the pyroreactor opening. 
     
     
         6 . The gasifier of  claim 1 , wherein the reduction basket is arranged with the basket opening proximal the pyroreactor outlet. 
     
     
         7 . The gasifier of  claim 6 , wherein the reduction basket closed end is perforated. 
     
     
         8 . The gasifier of  claim 6 , wherein the reduction basket further comprises a set of perforated walls extending between the closed end and the opening. 
     
     
         9 . The gasifier of  claim 6 , wherein the reduction basket further comprises an agitation mechanism. 
     
     
         10 . The gasifier of  claim 9 , wherein the agitation mechanism is configured to angularly agitate the reduction basket about an agitation axis extending substantially normal to the closed end. 
     
     
         11 . The gasifier of  claim 6 , wherein the reduction basket comprises a cone comprising an apex arranged proximal the basket opening and a base proximal the closed end. 
     
     
         12 . The gasifier of  claim 11 , wherein the cone comprises a substantially smooth exterior surface. 
     
     
         13 . The gasifier of  claim 1 , wherein the air inlets are directed toward the second end of the pyroreactor. 
     
     
         14 . The gasifier of  claim 13 , wherein the air inlets are arranged in a non-perpendicular angle relative to a plane defined by the pyroreactor opening, such that the air inlets induce rotational flow. 
     
     
         15 . The gasifier of  claim 1 , wherein the air manifolds are arranged between a pyroreactor exterior and a gasifier housing interior. 
     
     
         16 . The gasifier of  claim 15 , wherein an air manifold diameter is slightly less than a gap defined between the pyroreactor exterior and gasifier housing interior. 
     
     
         17 . The gasifier of  claim 1 , wherein the gasifier housing comprises an inner and outer wall cooperatively defining an annular void therebetween, wherein the inner wall comprises a gas inlet fluidly connected to the housing lumen. 
     
     
         18 . A gasification system comprising: a solid removal mechanism comprising:
 a screw conveyor comprising a helical screw blade configured to rotate about a rotational axis;   a feeder mechanism, comprising:
 a toothed perimeter configured to engage with the helical screw blade and rotate about a rotational axis, wherein helical screw blade rotation drives toothed perimeter rotation; 
 a set of feeder blades statically coupled to the toothed perimeter, the set of feeder blades arranged in a plane offset from a plane defined by the toothed perimeter; and 
   a drive mechanism coupled to the screw conveyor and configured to rotate the helical screw blade toward the feeder mechanism.   
     
     
         19 . The gasifier of  claim 18 , wherein the screw conveyor rotational axis is arranged at a non-zero angle relative to the plane defined by the toothed perimeter. 
     
     
         20 . The gasifier of  claim 18 , wherein the gasification system further comprises:
 a pyroreactor defining a first end, a second end, and an interior lumen, the first end defining a biomass inlet, the second end defining a pyroreactor outlet;   a reduction container arranged proximal the pyroreactor outlet, the reduction basket comprising a closed end and a basket opening opposing the closed end;   a set of air manifolds fluidly connected to the interior lumen of the pyroreactor through a set of air inlets arranged between the first and second ends, proximal the second end; and   a gasifier housing enclosing the pyroreactor, reduction basket, and set of air manifolds within a housing lumen, the gasifier housing comprising a set of walls and a bottom;   wherein the feeder mechanism is arranged between the reduction container and the gasifier bottom, and the screw conveyor is arranged outside an imaginary volume defined by an extension of the pyroreactor toward the feeder mechanism.