Burner With Open Radiant Tube

Abstract

A recuperative burner ( 10 ) fires a furnace chamber ( 11 ) in a substoichiometric manner. The recuperative burner is arranged in a radiant tube ( 26 ) which is open towards and protrudes into the furnace chamber. Together with the recuperator ( 18 ) or a protrusion ( 21 ), the radiant tube ( 26 ) forms an exhaust gas channel ( 19 ) into which burn-out air is introduced by an air conducting device ( 23 ). The post-combustion which occurs in the exhaust gas channel ( 19 ) heats the radiant tube ( 26 ). The furnace chamber ( 11 ) is heated partly directly by fuel and air and partly indirectly by the radiant tube ( 26 ). An excessive level of CO emission is prevented by the post-combustion in the exhaust gas channel ( 19 ). By using the resulting heat from the radiant tube ( 26 ), excessively high exhaust gas temperatures are prevented and the thermal use of the fuel is optimized.

1 . A burner ( 10 ) for heating a furnace ( 12 ) using preheated air and fuel exiting from a burner orifice ( 25 ), the burner comprising:
 a recuperator ( 18 ) arranged in or on an exhaust gas channel ( 19 ) for preheating air using exhaust gas heat,   a radiant tube ( 26 ) that has an opening ( 24 ) located at one end facing away from the burner ( 10 ) and that is arranged on the burner ( 10 ) to delimit the exhaust gas channel ( 19 ) in a peripheral direction,   an air conducting device ( 23 ) configured to introduce air into the exhaust gas channel ( 19 ).   
     
     
         2 . The burner according to  claim 1 , wherein the burner orifice ( 25 ) is arranged on a portion of the burner ( 10 ), said portion of the burner projecting from the opening ( 24 ) of the radiant tube ( 26 ). 
     
     
         3 . The burner according to  claim 1 , further comprising a tube section ( 21 ) provided with air outlet openings ( 22 ) which is connected as the air conducting device ( 23 ) to the recuperator ( 18 ). 
     
     
         4 . The burner according to  claim 3 , wherein the recuperator ( 18 ) and the tube section ( 21 ) are formed of a single piece of material and are configured so as to form a seamless transition. 
     
     
         5 . The burner according to  claim 1 , wherein the air conducting device ( 23 ) and the burner orifice ( 25 ) are connected to one common air channel in order to be supplied with air by the common air channel. 
     
     
         6 . The burner according to  claim 1 , wherein the burner orifice ( 25 ) and the air conducting device ( 23 ) are arranged with respect to each other and to a fuel stream such that an air stream dispensed by the burner orifice ( 25 ) results in a sub stoichiometric combustion. 
     
     
         7 . The burner according to  claim 6 , wherein a sum total of the air stream dispensed by the burner orifice ( 25 ) and an air stream dispensed by the air conducting device ( 23 ) is in a stoichiometric or superstoichiometric relationship with respect to the fuel stream. 
     
     
         8 . The burner according to  claim 1 , wherein the burner orifice ( 25 ) is oriented axially relative to the burner ( 10 ) and the radiant tube ( 26 ). 
     
     
         9 . The burner according to  claim 1 , wherein the burner orifice ( 25 ) comprises at least one opening ( 24 ) that is oriented obliquely or radially relative to a burner axis. 
     
     
         10 . The burner according to  claim 1 , wherein a thermal output of the radiant tube ( 26 ) is fixed at a value between 10% and 30% of a total thermal output of the burner ( 10 ). 
     
     
         11 . The burner according to  claim 1 , wherein the burner is disposed in a furnace chamber ( 11 ) of the furnace ( 12 ) to effect and maintain a flameless oxidation process. 
     
     
         12 . A method for heating a furnace chamber with a burner that comprises a radiant tube ( 26 ) that encloses an exhaust gas channel ( 19 ) and is open on its free end, the method comprising:
 operating the burner in a substoichiometric manner; and   supplementally introducing burn-out air into the exhaust gas channel.   
     
     
         13 . The method according to  claim 12 , further comprising using the burn-out air to maintain combustion in the exhaust gas channel, said combustion being utilized for heating the radiant tube ( 26 ). 
     
     
         14 . The method according to  claim 12 , further comprising directly heating the furnace chamber to a greater extent with hot gas produced by the burner ( 10 ) and indirectly heating the furnace chamber to a lesser extent with heat radiated by the radiant tube ( 26 ).