Burner with means for changing the direction of fuel flow

Abstract

A description is given of a burner for introducing solid, liquid or gaseous fuel to a burning zone of a kiln, such as a rotary kiln for manufacturing cement clinker or the like, said burner comprising a number of substantially concentric ducts ( 1, 2, 3 ), being parallel to the main axis B 3 of the burner, for conveying fuel and primary air to nozzle openings, as well as a number of additional ducts ( 4, 6, 7, 8 ) for conveying solid, fluid or gaseous fuel to separate nozzle openings, said additional ducts being located in the central part ( 10 ) of the burner. The burner is characterized in that it comprises means ( 4 a, 5 ) for changing the flow direction of the fuel which is introduced via at least one of the additional ducts in the central part ( 10 ) of the burner, relative to the main axis B 3 of the burner, at least in an ascending direction. This will allow the individual fuel particles to travel in a curved, approximately ballistic path, thereby extending the time they can be maintained in the flame. Another advantage of this configuration of the burner is that the large particles will attain the highest, and hence the longest, path, since the path of the smaller particles will to a greater extent than is the case for the large ones be deflected by the primary air which is injected via the outer annular primary air nozzle which is parallel to the main axis of the burner. Hence it will be possible to achieve a more uniform combustion of all particles, regardless of their size. It will be possible to change the path of the particles by altering the velocity or direction of injection.

1 - 10 . (canceled) 
   
   
       11 . A burner for introducing solid, liquid or gaseous fuel to a burning zone of a kiln, such as a rotary kiln for manufacturing cement clinker or the like, said burner comprising a number of substantially concentric ducts, which are parallel to a main axis of the burner, for conveying fuel and primary air to nozzle openings, and a number of additional ducts for conveying solid, fluid or gaseous fuel to separate nozzle openings, with said additional ducts being located in the central part of the burner, wherein the burner comprises means for changing the flow direction of the fuel which is introduced via at least one of the additional ducts in the central part of the burner, relative to the main axis B a  of the burner, at least partially in an ascending direction. 
   
   
       12 . A burner according to  claim 11 , wherein the means for changing the flow direction of the fuel being introduced via at least one of the additional ducts in the central part of the burner, comprises an introduction duct which is located at the outlet end of the duct in question in immediate extension hereof, with its centreline forming an angle relative to the main axis of the burner. 
   
   
       13 . A burner according to  claim 12 , wherein the introduction duct is arranged so that it points upward relative to the main axis B a  of the burner at an angle between 1° and 25° 
   
   
       14 . A burner according to  claim 12 , wherein the introduction duct is arranged so that it points upward relative to the main axis B a  of the burner at an angle between 5° and 15°. 
   
   
       15 . A burner according to  claim 12 , wherein the introduction duct is arranged so that it points upward relative to the main axis B a  of the burner at an angle between 7° and 10°. 
   
   
       16 . A burner according to  claim 11 , wherein the means for changing the flow direction of the fuel which is introduced via at least one of the additional ducts in the central part of the burner, comprises an air duct the outlet of which is located immediately at or at least partially enclosing the duct in question in such a way that the centre of gravity of the outlet cross-section of the air duct is displaced in relation to the centre of gravity of the outlet cross-section of the duct in question. 
   
   
       17 . A burner according to  claim 12 , wherein the means further comprises an air duct, the outlet of which is located immediately at or at least partially enclosing the duct in such a way that the point of gravity of the outlet cross-section of the air duct is displaced in relation to the centre of gravity of the outlet cross-section of the duct. 
   
   
       18 . A burner according to  claim 11 , wherein the means for changing the flow direction of the fuel which is introduced via at least one of the additional ducts in the central part of the burner comprises a separate air duct, the outlet of which is immediately at or at least partially enclosing the duct in question, and forming an angle relative to the main axis B a  of the burner. 
   
   
       19 . A burner according to  claim 18 , wherein the air duct is arranged so that it points upward relative to the main axis of the burner at an angle between 8° and 80°. 
   
   
       20 . A burner according to  claim 18 , wherein the air duct is arranged so that it points upward relative to the main axis of the burner at an angle between 35° and 60°. 
   
   
       21 . A burner according to  claim 12 , wherein the means further comprises a separate air duct, the outlet of which is immediately at or at least partially enclosing the duct in question, and forming an angle relative to the main axis B a  of the burner. 
   
   
       22 . A burner according to  claim 21 , wherein the air duct is located so that it points upward relative to the main axis at an angle between 8° and 80°. 
   
   
       23 . A burner according to  claim 21 , wherein the air duct is located so that it points upward relative to the main axis at an angle between 35° and 60°. 
   
   
       24 . A burner according to  claim 17 , wherein the air duct, having an outlet immediately at or at least partially enclosing the duct, forms an angle relative to the main axis B a  of the burner.