Method and burner assembly for combusting a fuel gas with an oxidant

Abstract

The invention relates to a method for combusting a fuel gas with an oxidant by using a burner assembly ( 10 ) comprising a burner ( 12 ) and a lance ( 14 ), the method comprising providing via the burner ( 12 ) a main gas flow to a combustion, wherein the main gas flow comprises a main part of the fuel gas and a first part of the oxidant. Further, the method comprises providing via the lance ( 14 ) a staging gas flow to the combustion, wherein the staging gas flow comprises a second part of the oxidant and an auxiliary part of the fuel gas. The main part of the fuel gas is larger than the auxiliary part of the fuel gas. Furthermore, the invention relates to a burner assembly ( 10 ) and a furnace comprising such.

1 - 14 . (canceled) 
     
     
         15 . A method for combusting a fuel gas with an oxidant by using a burner assembly ( 10 ) comprising a burner ( 12 ) and a lance ( 14 ), the method comprising:
 providing via the burner ( 12 ) a main gas flow to a combustion, wherein the main gas flow comprises a main part of the fuel gas and a first part of the oxidant; and   providing via the lance ( 14 ) a staging gas flow to the combustion, wherein the staging gas flow comprises a second part of the oxidant and an auxiliary part of the fuel gas;   wherein the main part of the fuel gas is larger than the auxiliary part of the fuel gas, and wherein the auxiliary part of the fuel gas provided via the lance is selected from the group consisting of not more than 20% of the total fuel gas provided to the combustion, not more than 10% of the total fuel gas provided to the combustion, not more than 5% of the total fuel gas provided to the combustion, and not more than 2% of the total fuel gas provided to the combustion.   
     
     
         16 . The method according to  claim 15 , wherein the auxiliary part of the fuel gas preheats at least a part of the staging gas flow before the staging gas flow is provided to the combustion. 
     
     
         17 . The method according to  claim 15 , wherein the first part of the oxidant provided via the burner ( 12 ) is selected from the group consisting of not more than 95% of the total oxidant provided to the combustion, not more than 90% of the total oxidant provided to the combustion, not more than 80% of the total oxidant provided to the combustion, not more than 70% of the total oxidant provided to the combustion, and not more than 60% of the total oxidant provided to the combustion. 
     
     
         18 . The method according to  claim 15 , wherein the second part of the oxidant provided via the lance ( 14 ) is selected from the group consisting of at least 5% of the total oxidant provided to the combustion, at least 10% of the total oxidant provided to the combustion, at least 20% of the total oxidant provided to the combustion, at least 30% of the total oxidant provided to the combustion, and at least 40% of the total oxidant provided to the combustion. 
     
     
         19 . The method according to  claim 15 , wherein the burner assembly ( 10 ) comprises a plurality of burners ( 12 ) for providing the main gas flow to the combustion, and a burner block ( 16 ) comprising multiple outlet areas ( 28 ,  30 ) for ejecting at least a part of the combusted fuel gas and at least a part of the oxidant. 
     
     
         20 . The method according to  claim 15 , wherein the burner assembly ( 10 ) comprises a plurality of lances ( 14 ), wherein each of the plurality of lances ( 14 ) provides one of a plurality of staging gas flows to the combustion. 
     
     
         21 . The method according to  claim 15 , wherein an amount of the auxiliary part of the fuel gas in the staging gas flow is adjustable. 
     
     
         22 . A burner assembly ( 10 ) for combusting a fuel gas with an oxidant, the burner assembly ( 10 ) comprising:
 a burner ( 12 ) for providing a main gas flow to a combustion, wherein the main gas flow comprises a main part of the fuel gas and a first part of the oxidant;   a lance ( 14 ) for providing a staging gas flow to the combustion, wherein the staging gas flow comprises a second part of the oxidant and an auxiliary part of the fuel gas; and   an injection element for injecting the auxiliary part of the fuel gas to the second part of the oxidant before providing the staging gas flow to the combustion via the lance ( 14 );   wherein the main part of the fuel gas is larger than the auxiliary part of the fuel gas, and wherein the auxiliary part of the fuel gas provided via the lance is selected from the group consisting of not more than 20% of the total fuel gas provided to the combustion, not more than 10% of the total fuel gas provided to the combustion, not more than 5% of the total fuel gas provided to the combustion, and not more than 2% of the total fuel gas provided to the combustion.   
     
     
         23 . The burner assembly ( 10 ) according to  claim 22 , further comprising control means for adjusting an amount of the auxiliary part of the fuel gas in the staging gas flow. 
     
     
         24 . The burner assembly ( 10 ) according to  claim 22 , wherein the burner assembly comprises a plurality of the burners ( 12 ) for providing the main gas flow to the combustion, and a burner block ( 16 ) comprising multiple outlet areas ( 28 ,  30 ) for ejecting at least a part of the combusted fuel gas and at least a part of the oxidant. 
     
     
         25 . The burner assembly ( 10 ) according to  claim 22 , further comprising an outlet area ( 28 ,  30 ) of the burner block ( 16 ) for the fuel gas and for the lance ( 14 ), the outlet area including a substantially rectangular shape, wherein the outlet area ( 28 ,  30 ) includes a ratio of its width to its height selected from the group consisting of at least 3:1, at least 4:1, at least 5:1, at least 6:1, and at least 6.5:1. 
     
     
         26 . The burner assembly ( 10 ) according to  claim 22 , further comprising a plurality of the lances ( 14 ), wherein each of the plurality of the lances ( 14 ) is adapted to provide one of a plurality of staging gas flows to the combustion. 
     
     
         27 . The burner assembly according to  claim 22 , wherein the burner ( 12 ) comprises a flat flame burner. 
     
     
         28 . A furnace comprising the burner assembly ( 10 ) according to  claim 22 .