Charcoal/ash removal system for a downdraft gasifier and associated methods

Abstract

A method and apparatus is provided for use in a fixed-bed gasification system for the disengagement of gas and the removal of ash and charcoal. In one example, the invention includes an auger system, a water seal system, and a gas disengagement system. The gas disengagement mechanism prevents plugging and blinding of the gas offtake system and simultaneously limits particulate entrainment in the gas produced by the gasifier.

1 . A system for disengaging gas and removing charcoal and ash in a fixed-bed gasification system comprising:
 a conveying system configured to be disposed below a gasifier for conveying charcoal and ash away from the gasifier;   a vertical gas discharge port in communication with the conveying system; and   a water seal in communication with the discharge port for preventing gas from passing through the water seal.   
   
   
       2 . The system of  claim 1 , wherein the conveying system includes an auger. 
   
   
       3 . The system of  claim 1 , wherein the conveying system includes two or more augers. 
   
   
       4 . The system of  claim 1 , wherein the water seal further comprises a water tank. 
   
   
       5 . The system of  claim 1 , wherein the conveying system includes a discharge port that extends into a water tank. 
   
   
       6 . The system of  claim 1 , wherein the vertical discharge port extends upward from the conveying system. 
   
   
       7 . The system of  claim 1 , wherein the water seal is configured to provide an air tight seal between the gasifier and the atmosphere. 
   
   
       8 . A method of disengaging gas and removing charcoal and ash in a fixed-bed gasifier comprising:
 providing a conduit disposed generally below the gasifier, and extending away from the gasifier;   conveying charcoal and ash away from the gasifier through the conduit;   forming a vertical gas discharge port in the conduit, allowing gases produced by the gasifier to exit the gasifier; and   sealing an end of the conduit with a water seal for preventing gas from passing through the water seal.   
   
   
       9 . The method of  claim 8 , wherein conveying charcoal and ash away from the gasifier through the conduit further comprises using an auger to convey the charcoal and ash. 
   
   
       10 . The method of  claim 8 , wherein conveying charcoal and ash away from the gasifier through the conduit further comprises using two or more augers to convey the charcoal and ash. 
   
   
       11 . The method of  claim 8 , wherein sealing an end of the conduit with a water seal further comprises configuring the conduit to extend into a water tank. 
   
   
       12 . The method of  claim 8 , further comprising configuring the vertical discharge port to extend upward from the conduit. 
   
   
       13 . The method of  claim 8 , wherein the water seal provides an air tight seal between the gasifier and the atmosphere. 
   
   
       14 . A gas discharge system for a fixed-bed gasification system having a gasifier and an auger system for conveying charcoal and ash away from the gasifier, the gas discharge system comprising:
 a discharge port extending upward from the auger system for allowing gases produced by the gasifier to exit the gasifier.   
   
   
       15 . The gas discharge system of  claim 14 , further comprising a water seal for sealing an end of the auger system. 
   
   
       16 . The gas discharge system of  claim 14 , wherein the water seal further comprises a water tank. 
   
   
       17 . The gas discharge system of  claim 14 , wherein the auger system includes two or more augers.