Method and System for controlling coal flow

Abstract

A system for controlling coal flow in a coal-fired boiler including: a coal flow damper in operable communication with a burner pipe; a coal flow sensor in operable communication with the burner pipe which generates a coal flow signal; and a fuel trim controller in operable communication with the coal flow damper, the fuel trim controller controlling the coal flow damper responsive to the coal flow signal.

1 . A system for controlling coal flow in a coal-fired boiler comprising: 
 a coal flow damper in operable communication with a burner pipe;    a coal flow sensor in operable communication with said burner pipe, which generates a coal flow signal; and    a fuel trim controller in operable communication with said coal flow damper, said fuel trim controller controlling said coal flow damper responsive to said coal flow signal.    
   
   
       2 . The system of  claim 1  wherein said fuel trim controller comprises a physics-based mill circuit coal flow model capable of predicting changes in burner coal flow velocity as a result of coal flow damper adjustments wherein said fuel trim controller maintains a specific coal flow velocity range in said burner pipe.  
   
   
       3 . The system of  claim 1  wherein said coal flow damper comprises a flow restrictor and an actuator in operable communication with said flow restrictor.  
   
   
       4 . The system of  claim 3  wherein said fuel trim controller adjusts a position of said flow restrictor with said actuator.  
   
   
       5 . The system of  claim 4  wherein said fuel trim controller autonomously adjusts a position of said flow restrictor with said actuator responsive to said coal flow signal.  
   
   
       6 . The system of  claim 1  wherein said fuel trim controller autonomously controls said coal flow damper responsive to said coal flow signal.  
   
   
       7 . The system of  claim 6  wherein said fuel trim controller maintains a predetermined coal flow rate set by a user.  
   
   
       8 . The system of  claim 6  wherein said fuel trim controller maintains a prescribed coal flow biasing among a plurality of burner pipes.  
   
   
       9 . The system of  claim 8  wherein said fuel trim controller is capable of storing preferred bias set points for different operating conditions of the coal-fired boiler.  
   
   
       10 . A method for controlling coal flow in a coal-fired boiler comprising: 
 sensing a coal flow in a burner pipe;    generating a coal flow signal indicative of said coal flow in said burner pipe; and    adjusting said coal flow in said burner pipe responsive to said coal flow signal.    
   
   
       11 . The method of  claim 10  wherein a fuel trim controller controls said coal flow damper responsive to said coal flow signal.  
   
   
       12 . The method of  claim 10  wherein said coal flow damper comprises a flow restrictor and an actuator affixed to said flow restrictor.  
   
   
       13 . The method of  claim 12  wherein said adjusting said coal flow in a burner pipe with a burner coal flow damper is achieved by controlling a position of said flow restrictor with said actuator.  
   
   
       14 . The method of  claim 10  wherein said adjusting said coal flow in said burner pipe reduces at least one of the following: 
 a NO x  emission;    a FEGT; or    a unburned carbon on fly ash.    
   
   
       15 . The method of  claim 10  wherein said adjusting said coal flow in said burner pipe improves spatial combustion.  
   
   
       16 . A system for controlling coal flow in a coal-fired boiler comprising: 
 means for sensing a coal flow in a burner pipe;    means for adjusting the coal flow in said burner pipe responsive to the coal flow in said burner pipe.    
   
   
       17 . The system of  claim 16  further comprising means for maintaining a prescribed coal flow bias among a plurality of burner pipes for the coal-fired boiler.  
   
   
       18 . The system of  claim 16  further comprising means for automatically balancing coal flow among a plurality of burner pipes for the coal-fired boiler.  
   
   
       19 . The system of  claim 16  further wherein said means for adjusting the coal flow in a burner pipe responsive to the coal flow in a burner pipe improves spatial combustion.  
   
   
       20 . The system of  claim 16  further wherein said means for adjusting the coal flow in a burner pipe responsive to the coal flow in a burner pipe reduces at least one of the following: 
 a NO x  emission;    a FEGT; or    a unburned carbon on fly ash.