Method and apparatus for controlling gasifier efficiency

Abstract

In a gasifier system, the gas thermal conductivity of the producer gas may beneficially be used as a control variable in controlling the combustion parameters of the gasifier process or gasifier system. For example, the control variable may be used to modulate the volume amount of air provided to a gasifier vessel or to modulate an oxidizer delivery rate.

1 . A method for controlling a gasifier system, comprising:
 detecting a thermal conductivity of a producer gas from a gasifier vessel; and   controlling an operating efficiency of the gasifier vessel based on the detected thermal conductivity.   
     
     
         2 . The method of  claim 1 , wherein controlling the operating efficiency includes controlling a volume of air provided to the gasifier vessel. 
     
     
         3 . The method of  claim 1 , wherein controlling the operating efficiency includes controlling a rate of oxidizer provided to the gasifier vessel. 
     
     
         4 . The method of  claim 1 , wherein the thermal conductivity is repeatedly detected so that controlling the operating efficiency is performed continuously. 
     
     
         5 . The method of  claim 1 , further comprising:
 drying the producer gas from the gasifier vessel before detecting the thermal conductivity.   
     
     
         6 . The method of  claim 1 , further comprising:
 determining a high temperature and a low temperature for combustion within the gasifier vessel, which bound an allowable air input to the gasifier vessel.   
     
     
         7 . The method of  claim 6 , wherein the high temperature and the low temperature relate to a fuel used in the gasifier vessel. 
     
     
         8 . The method of  claim 6 , wherein the high temperature and the low temperature relate to a moisture content of fuel used in the gasifier vessel. 
     
     
         9 . The method of  claim 6 , further comprising:
 determining an optimal thermal conductivity value within bounds of the high temperature and the low temperature; and   controlling the operating efficiency so that the thermal conductivity of the producer gas is maintained substantially equal to the optimal thermal conductivity value.   
     
     
         10 . The method of  claim 1 , wherein the step of detecting thermal conductivity includes comparing the thermal conductivity of the producer gas with that of a reference gas. 
     
     
         11 . An apparatus for controlling a gasifier system, comprising:
 a gasifier vessel;   a thermal conductivity detector configured to detect thermal conductivity of a producer gas from a gasifier vessel; and   a controller configured to control an operating efficiency of the gasifier vessel based on the detected thermal conductivity.   
     
     
         12 . The apparatus of  claim 11 , wherein the controller includes a fan configured to control a volume of air provided to the gasifier vessel. 
     
     
         13 . The apparatus of  claim 11 , wherein the controller includes a valve configured to control a rate of oxidizer provided to the gasifier vessel. 
     
     
         14 . The apparatus of  claim 11 , further comprising:
 determination circuitry configured to determine a high temperature and a low temperature for combustion within the gasifier vessel, which bound an allowable air input to the gasifier vessel, the high temperature and the low temperature relating to a fuel used in the gasifier vessel.   
     
     
         15 . The apparatus of  claim 14 , wherein the controller is configured to control the operating efficiency so that the thermal conductivity of the producer gas is maintained substantially equal to an optimal thermal conductivity value, wherein the optimal thermal conductivity value is selected within bounds of the high temperature and the low temperature. 
     
     
         16 . A system for controlling a gasifier system, comprising:
 a producer gas path having a first input and a first output, the first input configured to receive producer gas from a gasifier vessel and the first output configured to provide a producer gas component to a thermal conductivity sensor;   a reference gas path having a second input and a second output, the first input configured to receive a reference gas and the second output configured to provide an output gas component to the thermal conductivity sensor;   the thermal conductivity sensor configured to provide an output signal related to a thermal conductivity of the producer gas component; and   a control system configured to control operation of the gasifier system based on the output signal.   
     
     
         17 . The system of  claim 16 , wherein the thermal conductivity sensor includes a first thermistor whose value varies based on the thermal conductivity of the producer gas component and a second thermistor whose value varies based on a thermal conductivity of the reference gas component. 
     
     
         18 . The system of  claim 16 , wherein a respective temperature of the reference gas component and the producer gas component are substantially equal. 
     
     
         19 . The system of  claim 16 , further comprising:
 a vent configured to shunt the producer gas based on the thermal conductivity of the producer gas component being outside of an allowable range of values.   
     
     
         20 . The system of  claim 16 , wherein the control system includes a volumetric air controller configured to control air provided to a gasifier vessel.