Single-fireball tangentially-firing boiler for the burning of anthracite

Abstract

A tangentially-fired furnace for the burning of anthracite is disclosed. The furnace may contain a boiler with a chamber having four corners. Four burner groups located at the four corners may be configured to eject pulverized coal flow into the chamber for combustion, in order to form a single fireball substantially at the center of the chamber during combustion. Each burner group may contain a first burner which includes primary-air/rich-portion nozzles for ejecting rich-portion coal flow into a lower section of the chamber, and a second burner which includes primary-air/thin-portion nozzles for ejecting thin-portion coal flow into a higher section of the chamber.

We claim: 
     
         1 . A tangentially-fired furnace for the burning of anthracite, comprising:
 a boiler ( 1 ) having a chamber ( 2 ) surrounded by four water-cooled walls ( 9 ), wherein the four water-cooled walls intersect one-another to form four corners in the chamber ( 2 ); and   four burner groups located at the four corners of the chamber ( 2 ) respectively, for ejecting pulverized-coal fuel to be ejected from the burner groups to combust and form a single fireball substantially at the center of the chamber ( 2 ),   wherein each of the four burner groups contains a first burner and a second burner vertically located in a corresponding corner of the four corners,
 the first burner is a primary-air/rich-portion burner located in a lower part of the chamber ( 2 ), ejecting a first concentration of pulverized-coal fuel to form a rich combustion area in the chamber ( 2 ), 
 the second burner is a primary-air/thin-portion burner located in an higher part of the chamber ( 2 ), ejecting a second concentration of pulverized-coal fuel to form a thin combustion area in the chamber ( 2 ), and 
 the first concentration is higher than the second concentration. 
   
     
     
         2 . The tangentially-fired furnace as recited in  claim 1 , wherein
 the first burner includes, in a vertical direction, one or more primary-air/rich-portion nozzles ( 6 ) and a first set of secondary-air nozzles ( 8 ), and   the primary-air/rich-portion nozzles ( 6 ) are intertwined with the first set of secondary-air nozzles ( 8 ).   
     
     
         3 . The tangentially-fired furnace as recited in  claim 2 , wherein
 the second burner includes, in the vertical direction, one or more primary-air/thin-portion nozzles ( 7 ) and a second set of secondary-air nozzles ( 8 ), and   the primary-air/thin-portion nozzles ( 7 ) are intertwined with the second set of secondary-air nozzles ( 8 ).   
     
     
         4 . The tangentially-fired furnace as recited in  claim 1 , wherein
 the first burner contains seven secondary-air nozzles ( 8 ) and six primary-air/rich-portion nozzles ( 6 ), and the second burner contains additional seven secondary-air nozzles ( 8 ) and six primary-air/thin-portion nozzles ( 7 ).   
     
     
         5 . The tangentially-fired furnace as recited in  claim 1 , further comprising:
 a pulverizer ( 3 ) coupled with one of the four burner groups, wherein
 the pulverizer ( 3 ) is configured to generate pulverized coal from anthracite, and contains one or more outlets for connecting with one or more distributors ( 4 ) via one or more pipes ( 5 ), 
 each of the distributors ( 4 ) is configured to separate the pulverized coal fuel into a rich-portion and a thin-portion, 
 the rich-portion is transported to the first burner of the one of the four burner groups, 
 the thin-portion is transported to the second burner of the one of the four burner groups, 
 the rich-portion is ejected via a primary-air/rich-portion nozzle ( 6 ) located in the first burner, and 
 the thin-portion is ejected via a primary-air/thin-portion nozzle ( 7 ) located in the second burner. 
   
     
     
         6 . The tangentially-fired furnace as recited in  claim 5 , wherein
 the pulverizer ( 3 ) is connected with four of the distributors ( 4 ) generating four rich-portion coal flows and four thin-portion coal flows,   the four rich-portion coal flows are transported to the corresponding four primary-air/rich-portion nozzles ( 6 ) in the four first burners of the four burner groups,   the four thin-portion coal flows are transported to the corresponding four primary-air/thin-portion nozzles ( 7 ) in the four second burners of the four burner groups,   the four primary-air/rich-portion nozzles ( 6 ) are located on a first horizontal flat plane, and   the four primary-air/thin-portion nozzles ( 7 ) are located on a second horizontal flat plane.   
     
     
         7 . The tangentially-fired furnace as recited in  claim 6 , wherein
 the rich-portion coal flow contains about 80% of the pulverized coal generated by the pulverizer ( 3 ) and about 50% of primary air,   the thin-portion coal flow contains about 20% of the pulverized coal generated by the pulverizer ( 3 ) and about 50% of the primary air, and   each of the primary-air/rich-portion nozzles ( 6 ) and the primary-air/thin-portion nozzles ( 7 ) are configured with perimeter airflow, and secondary air nozzles are configured to provide an offset airflow.   
     
     
         8 . The tangentially-fired furnace as recited in  claim 7 , wherein a first distance in a vertical direction between a specific primary-air/thin-portion nozzle ( 7 ) located at the top of the one of the corners and a specific primary-air/rich-portion nozzle ( 6 ) located at the bottom of the one of the corners is adjusted based on a second distance between the first burner and the second burner in the one of the corners.