Methods and apparatus for burning fuel with low NOx formation
First Claim
1. A method of discharging a substantially stoichiometric mixture of fuel gas and air into a furnace wherein said mixture is burned and flue gases having a low NOx content are formed therefrom comprising the steps of:
- (a) mixing a first portion of said fuel gas with a first portion of said air to form a primary fuel gas-air mixture;
(b) discharging said primary fuel gas-air mixture into a primary burning zone in said furnace from at least one primary fuel gas-air mixture discharge location surrounded by a wall which extends into said furnace;
(c) mixing a second portion of said fuel gas and a second portion of said air to form a secondary fuel gas-air mixture; and
(d) discharging said secondary fuel gas-air mixture into a secondary burning zone in said furnace from at least one secondary fuel gas-air mixture discharge location adjacent to an exterior side of said wall at a velocity whereby said secondary fuel gas-air mixture is not ignited and burned until said mixture spreads over said exterior side of said wall, mixes with flue gases in said furnace and flows beyond said wall.
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Accused Products
Abstract
Improved methods and apparatus for burning fuel with low NOx formation are provided. A method of the invention for discharging a mixture of fuel gas and air into a furnace wherein the mixture is burned and flue gases having a low NOx content are formed includes the following steps. A first portion of the fuel gas is mixed with a first portion of the air to form a primary fuel gas-air mixture. The primary fuel gas-air mixture is discharged into a primary burning zone in the furnace from at least one discharge location surrounded by a wall which extends into the furnace. A second portion of the fuel and a second portion of the air are mixed to form a secondary fuel gas-air mixture. The secondary fuel gas-air mixture is discharged into a secondary burning zone in the furnace from at least one discharge location adjacent to an exterior side of the wall. The secondary fuel gas-air mixture is discharged at a velocity whereby the secondary fuel gas-air mixture is not ignited and burned until the mixture spreads over an exterior side of the wall, mixes with flue gases in the furnace and flows beyond the wall.
62 Citations
15 Claims
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1. A method of discharging a substantially stoichiometric mixture of fuel gas and air into a furnace wherein said mixture is burned and flue gases having a low NOx content are formed therefrom comprising the steps of:
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(a) mixing a first portion of said fuel gas with a first portion of said air to form a primary fuel gas-air mixture;
(b) discharging said primary fuel gas-air mixture into a primary burning zone in said furnace from at least one primary fuel gas-air mixture discharge location surrounded by a wall which extends into said furnace;
(c) mixing a second portion of said fuel gas and a second portion of said air to form a secondary fuel gas-air mixture; and
(d) discharging said secondary fuel gas-air mixture into a secondary burning zone in said furnace from at least one secondary fuel gas-air mixture discharge location adjacent to an exterior side of said wall at a velocity whereby said secondary fuel gas-air mixture is not ignited and burned until said mixture spreads over said exterior side of said wall, mixes with flue gases in said furnace and flows beyond said wall. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification