Fuel dilution methods and apparatus for NOx reduction
AssigneeJohn Zink Company
InventorJerry M. Lang
Life of this patent
Estimating the term…
Abstract
Methods and apparatus for reducing the content of nitrogen oxides in the flue gases produced by the combustion of fuel gas and combustion air introduced into a burner connected to a furnace are provided. The methods basically comprise the steps of conducting the combustion air to the burner, providing a chamber outside of the burner and furnace for mixing flue gases from the furnace with the fuel gas, discharging the fuel gas in the form of a fuel jet into the mixing chamber so that flue gases from the furnace are drawn into the chamber and mixed with and dilute the fuel gas therein and conducting the resulting mixture of flue gases and fuel gas to the burner wherein the mixture is combined with the combustion air and burned in the furnace.
Claims21
A method of reducing the content of nitrogen oxides in flue gases produced by the combustion of an at least substantially stoichiometric mixture of fuel gas and combustion air introduced into a burner connected to a furnace comprising the steps of:
- (a) conducting said combustion air to said burner;
- (b) providing a chamber outside of said burner and furnace for mixing flue gases from said furnace with said fuel gas, said chamber including a fuel gas jet-forming nozzle and a venturi and mixing compartment therein;
- (c) discharging said fuel gas in the form of a fuel gas jet into said mixing chamber by way of said fuel gas jet-forming nozzle so that flue gases from said furnace are drawn into said chamber and mix with and dilute said fuel gas in said venturi and mixing compartment therein;
- and
- (d) conducting the mixture of flue gases and fuel gas formed in step (c) to said burner wherein said mixture is combined with said combustion air and burned therein and in said furnace.
A method of reducing the content of nitrogen oxides in flue gases produced by the combustion of an at least substantially stoichiometric mixture of fuel gas and combustion air introduced into a burner connected to a furnace comprising the steps of:
- (a) conducting said combustion air to said burner;
- (b) providing a chamber outside of said burner and furnace for mixing flue gases from said furnace with said fuel gas, said chamber including a fuel gas jet-forming nozzle and a venturi and mixing compartment therein;
- (c) discharging said fuel gas in the form of a fuel gas jet into said mixing chamber by way of said fuel gas jet-forming nozzle so that flue gases from said furnace are drawn into said chamber and mix with and dilute said fuel gas in said venturi and mixing compartment therein;
- (d) controlling the volume ratio of said flue gases mixed with said fuel gas in step (c);
- and
- (e) conducting the mixture of flue gases and fuel gas formed in step (c) to said burner wherein said mixture is combined with said combustion air and burned therein and in said furnace.
An apparatus for reducing the content of nitrogen oxides in flue gases produced by the combustion of an at least substantially stoichiometric mixture of fuel gas and combustion air, said fuel gas being conducted to a burner connected to a furnace by a fuel gas conduit and the combustion air being conducted from a source of combustion air to the burner by a combustion air conduit, comprising:
- a chamber for mixing flue gases from said furnace with said fuel gas having a fuel gas inlet for connection to said fuel gas conduit, a fuel gas jet-forming nozzle for forming a fuel gas jet within said chamber, a flue gases inlet positioned so that flue gases are drawn into said chamber by said fuel gas jet, a venturi and mixing compartment therein for mixing said flue gases and fuel gas and a flue gases-fuel gas mixture outlet;
- a first flue gases conduit for connection to said furnace connected to said flue gases inlet of said chamber;
- and
- a flue gases-fuel gas mixture conduit for connection to said burner connected to said flue gases-fuel gas mixture outlet of said chamber.
Dependencies are inferred from the claim text.