Gasifier and Incinerator for Biomass Sludge Destruction

Abstract

A device for gasifying biomass sludge having particle size less than 1 cm, and 20% to 100% solids content has a primary chamber, a fume transfer vent, a mixing chamber which accepts fumes from the primary chamber, and an afterburner chamber in fluid communication with the mixing chamber. A secondary burner produces an initial heating flame within a vertical portion of the afterburner chamber. A heat transfer chamber is in fluid communication with the afterburner chamber. Heated gases from the afterburner chamber cause heating of the heat transfer chamber. The primary chamber has a heat conductive floor superimposed over the heat transfer chamber so that conductive and convective heating of the primary chamber occur. At least one primary auger is located crosswise in the primary chamber between a sludge feed hopper and an ash hopper. The heat transfer chamber underlies the primary auger near the end at the ash hopper.

1 . A gasifier and incinerator for use in gasifying biomass waste in the form of a sludge having particle size not greater than 1 cm, and having 20% to 100% solids content with the rest being liquid, said gasifier and incinerator comprising:
 a primary chamber adapted to receive biomass sludge therein for gasification and incineration thereof;   a fume transfer vent disposed near the top of said primary chamber, said fume transfer vent being in fluid communication with said primary chamber, to permit the escape of fumes from said primary chamber;   a mixing chamber in fluid communication with said fume transfer vent to accept said fumes from said primary chamber;   an afterburner chamber in fluid communication with said mixing chamber;   a secondary burner member situated in said gasifier so as to produce an initial heating flame within a first vertically disposed portion of said afterburner chamber, said burner member having a fuel inlet and an air inlet to permit the supply of fuel and oxygen gas, respectively, to said burner member, and control means to control the supply of fuel and oxygen to said burner member;   a partitioning wall disposed between said mixing chamber and said primary chamber, wherein said partitioning wall defines the bottom limit of said transfer vent;   a heat transfer chamber in fluid communication with said afterburner chamber, wherein heated gases flowing from said afterburner chamber cause heating of said heat transfer chamber;   wherein said primary chamber has a heat conductive floor and is superimposed on said heat transfer chamber with said heat conductive floor being disposed in separating relation therebetween so as to permit conductive and convective heating of said primary chamber;   an exhaust vent in fluid communication with said heat transfer chamber for venting said fumes into said ambient surroundings;   at least one primary auger located crosswise in said primary chamber, and being in communication at a first end with a sludge feed hopper and at a second end with an ash hopper;   drive means to rotate said at least one primary auger so as to drive biomass sludge through said primary chamber from said sludge feed hopper to said ash hopper, across said heat conductive floor; and   wherein said heat transfer chamber underlies said at least one primary auger near the second end thereof.   
   
   
       2 . The gasifier and incinerator of  claim 1 , wherein the dwell time of said biomass sludge as it passes across said primary chamber from said sludge feed hopper to said ash hopper is in the range of 20 minutes to 3 hours. 
   
   
       3 . The gasifier and incinerator of  claim 1 , where an additional supply of air or oxygen is provided to said primary chamber on the side thereof which overlies said heat transfer chamber. 
   
   
       4 . The gasifier and incinerator of  claim 1 , further comprising a first liquid extraction chamber overlying said primary chamber and in heat transfer relation therewith;
 a secondary auger located crosswise in said first liquid extraction chamber, and having drive means to drive biomass sludge between a sludge feed hopper and an intermediate sludge feed hopper which is in communication with said first end of said at least one primary auger;   whereby when the biomass sludge to be gasified and incinerated has a high liquid content, at least some of the liquid is driven off in said first liquid extraction chamber by heat being transferred thereto from said primary chamber.   
   
   
       5 . The gasifier and incinerator of  claim 1 , further comprising a dividing wall located lengthwise in said primary chamber and having a height less than that of said primary chamber, and having an opening therein through which said auger passes so as to drive biomass sludge from said sludge feed hopper to said ash hopper. 
   
   
       6 . The gasifier and incinerator of  claim 1 , wherein said mixing chamber is generally vertically disposed. 
   
   
       7 . The gasifier and incinerator of  claim 1 , wherein said burner member is disposed at the top of said mixing chamber. 
   
   
       8 . The gasifier and incinerator of  claim 1 , wherein said partitioning wall is variable in height. 
   
   
       9 . The gasifier and incinerator of  claim 1 , wherein said afterburner chamber has a vertically disposed first portion and a horizontally disposed second portion. 
   
   
       10 . The gasifier and incinerator of  claim 9 , wherein said vertically disposed first portion of said afterburner chamber is connected in fluid communication to said horizontally disposed second portion of said afterburner chamber by way of a 90° corner. 
   
   
       11 . The gasifier and incinerator of  claim 10 , wherein said 90° corner has a “corner to corner” distance that is greater than the width of the afterburner chamber, so as to thereby effectively increase the cross-sectional area of the afterburner chamber at that point. 
   
   
       12 . A method of continuously gasifying and incinerating biomass waste in the form of a sludge having particle size not greater than 1 cm, and having 20% to 100% solids content with the rest being liquid, said method comprising the steps of:
 placing a quantity of biomass sludge in a sludge feed hopper and introducing some biomass sludge into a primary chamber of a gasifier and incinerator by driving said biomass sludge across said primary chamber with an auger;   starting a burner member located within said gasifier so as to produce an initial heating flame directed through a mixing chamber and vertically disposed only within an afterburner chamber;   heating a heat transfer chamber initially by way of said initial heating flame, whereby the radiation from said flame is precluded from directly entering said primary chamber;   heating said biomass sludge in said primary chamber by way of conductive and convective heating only from said heat transfer chamber, so as to preclude physical disturbance of said biomass sludge except by said auger;   channeling fumes from said biomass sludge into said mixing chamber:   using the heat from the oxidation of said fumes to further heat said heat transfer chamber;   extracting said fumes from said heat transfer chamber; and   continually feeding more biomass sludge to a first end of said auger and removing ash from an ash hopper located at a second end of said auger.   
   
   
       13 . The method of  claim 12  for gasifying and incinerating biomass sludge, wherein said initial heating flame is directed through a generally vertically disposed mixing chamber. 
   
   
       14 . The method of  claim 12  for gasifying and incinerating biomass sludge, wherein said burner member is located within said gasifier so as to be disposed at the top of said mixing chamber. 
   
   
       15 . The method of  claim 12  for gasifying and incinerating biomass sludge, wherein said initial heating flame is directed into an afterburner chamber having a vertically disposed first portion and a horizontally disposed second portion.