Pulverized coal burner for firing fuel which is fed by dense phase conveyance

Abstract

With a burner, especially pulverized coal burner, with a fuel conveying tube and a primary air tube which is concentrically arranged within it, wherein the primary air tube on the mouth discharge side terminates at a distance to the mouth opening of the fuel conveying tube, and the burner is connected, or can be connected, to a feed line which conveys pulverous fuel in dense phase, a solution is to be created which enables a low-NO X burner, which is suitable for firing the furnace of a steam generator, to be equipped with a dense phase conveyance of the fuel, without the low-NO X combustion characteristic being disadvantageously affected. This is achieved by the inside space of the primary air tube being able to be connected, or being connected, to a primary air feed line, and by the fuel conveying space, which is formed between the primary air tube and the fuel conveying tube, being able to be connected, or being connected, to the feed line which feeds pulverous fuel to the burner in dense phase.

1 . A burner, comprising:
 a fuel conveying tube; and   a primary air tube concentrically arranged within the fuel conveying tube, a mouth of a discharge side of the primary air tube terminating at a distance to a mouth of a discharge side of the fuel tube,   wherein the burner is connectable to a feed line which conveys a pulverous fuel in a dense phase,   wherein an inside space of the primary air tube is connectable to a primary air feed line, and   wherein a fuel conveying space which is formed between the primary air tube and the fuel conveying tube is connectable to the feed line which feeds the pulverous fuel in the dense phase to the burner.   
   
   
       2 . The burner of  claim 1 , wherein the burner is a pulverized coal burner. 
   
   
       3 . The burner of  claim 1 , further comprising:
 at least one swirler arranged in the inside space of the primary air tube.   
   
   
       4 . The burner of  claim 1 , further comprising:
 a core air tube arranged concentrically within the primary air tube.   
   
   
       5 . The burner of  claim 4 , wherein a first radial distance between the core air tube and the primary air tube is greater than a second radial distance between the primary air tube and the fuel conveying tube. 
   
   
       6 . The burner of  claim 4 , wherein the core air tube extends in a longitudinal axial direction beyond the mouth of the discharge side of the primary air tube into a region of the mouth of the discharge side of the fuel conveying tube. 
   
   
       7 . The burner of  claim 4 , further comprising:
 a plurality of swirlers circumferentially distributed on an outer surface of the core air tube and arranged radially on the outer surface in an annular passage to the primary air tube.   
   
   
       8 . The burner of  claim 7 , wherein the plurality of swirlers are arranged as a vane ring, 
   
   
       9 . The burner of  claim 4 , further comprising:
 an ignition lance coaxially arranged in the core air tube.   
   
   
       10 . The burner of  claim 9 , wherein the ignition lance is an oil burner ignition lance. 
   
   
       11 . The burner according to  claim 1 , further comprising:
 a secondary air feed encompassing the fuel conveying tube.   
   
   
       12 . The burner according to  claim 11 , further comprising:
 a tertiary air feed encompassing the secondary air feed.   
   
   
       13 . The burner according to  claim 1 , further comprising:
 a radially inwards extending stabilizing ring arranged at an end on a combustion chamber mouth side of the fuel conveying tube.   
   
   
       14 . A method for combusting particulate fuel in a burner, comprising:
 feeding the fuel to the burner by a dense phase conveyance;   conveying, by the dense phase conveyance, the fuel inside the burner along a longitudinal axis of the burner, the fuel being conveyed inside the burner in an annular passage-form fuel conveying space which is formed radially outside a primary air line;   mixing the fuel with a combustion air; and   admixing the primary air stream, which issues from a primary air line, in a swirled state with the fuel stream after a discharge from the fuel conveying space inside a fuel conveying tube of the burner.   
   
   
       15 . The method of  claim 14 , wherein the fuel includes at least one of a pulverized coal and a dry brown coal. 
   
   
       16 . The method of  claim 14 , wherein the primary air is admixed with the fuel stream in a mouth region of the burner in a mixing space before a discharge into a furnace. 
   
   
       17 . The method of  claim 14 , wherein the primary air stream is one of (a) air, (b) heated air, (c) recirculated flue gas and (d) a mixture of air and recirculated flue gas.