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US 2010/0248175 A1Published application
NOx Suppression Techniques for a Rotary Kiln
AssigneeFives North American Combustion, Inc.
InventorsBruce E. Cain, Thomas F. Robertson, John J. Nowakowski
Life of this patent
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Abstract
A NOx suppression apparatus is configured for use with a burner that injects fuel into a stream of process air flowing into and through a rotary kiln. The apparatus comprises a premix injection system that forms a premix of fuel gas and air, and injects the premix into the stream of process air upstream of the burner port. This enables premix products of combustion to suppress the production of NOx by vitiating a combustion air portion of the process air before the combustion air portion combusts with fuel injected from the burner port.
Claims32
An apparatus comprising:
- a rotary kiln having an inlet end configured to receive material to be processed at an elevated temperature and an outlet end configured to discharge processed material;
- a burner having a port for injecting fuel;
- a blower system configured to drive a stream of process air through the kiln to provide air for processing material in the kiln, and to provide combustion air for fuel injected from the burner;
- and
- a premix injection system configured to form a premix of fuel gas and air, and to inject the premix into the stream of process air upstream of the burner port, whereby products of premix combustion can suppress the production of NOx by vitiating a combustion air portion of the process air before the combustion air portion combusts with fuel injected from the burner port.
2 more elements
An apparatus comprising:
- a rotary kiln having an inlet end configured to receive material to be processed at an elevated temperature and an outlet end configured to discharge processed material;
- a burner having a port for injecting fuel into the rotary kiln;
- a blower system configured to drive a stream of process air through the rotary kiln to provide air for processing material in the rotary kiln, and to provide combustion air for fuel injected from the burner;
- and
- a premix injection system configured to form a premix of fuel gas and air, and to inject the premix into the stream of process air beside the burner port, whereby products of premix combustion can suppress the production of NOx by vitiating a combustion air portion of the process air before the combustion air portion combusts with fuel injected from the burner port.
2 more elements
An apparatus for use with a burner having a port for injecting fuel into a stream of process air flowing into and through a rotary kiln, the apparatus comprising:
- a premix injection system configured to form a premix of fuel gas and air, and to inject the premix into the stream of process air, including an annular premix injector port surrounding the burner port, whereby premix injected from the annular premix injector port can suppress the production of NOx by forming a tubular region of vitiation through which a combustion air portion of the process air can flow before combusting with fuel injected from the kiln burner port.
An apparatus for use with a burner having a port for injecting fuel into a stream of process air flowing into and through a rotary kiln, the apparatus comprising:
- a premix injection system configured to form a premix of fuel gas and air, and to inject the premix into the stream of process air, including an arcuate premix injector port extending partially around the burner port, whereby premix injected from the arcuate premix injector port can suppress the production of NOx by forming an arcuate region of vitiation through which a combustion air portion of the process air can flow before combusting with fuel injected from the kiln burner port.
An apparatus comprising:
- a rotary kiln with an outlet end;
- a hood having an opening to receive a flow of process air, the hood being configured to convey the flow of process air from the opening to the outlet end of the rotary kiln;
- a burner having a port for injecting fuel into the flow of process air downstream of the hood opening;
- and
- a premix injection system configured to form a premix of fuel gas and air, and to inject the premix into the flow of process air between the hood opening and the burner port, whereby the premix products of combustion can suppress the production of NOx by vitiating a combustion air portion of the process air before the combustion air portion combusts with fuel injected from the burner port.
2 more elements
A method comprising:
- providing material to be processed at an elevated temperature;
- moving the material through a rotary kiln having an inlet end configured to receive material to be processed and an outlet end configured to discharge processed material;
- injecting fuel from a burner port into the rotary kiln;
- driving a stream of process air through the rotary kiln to provide air for processing the material moving through the rotary kiln, and to provide combustion air for fuel injected from the burner;
- forming a premix of fuel gas and air;
- and
- injecting the premix into the stream of process air upstream of the burner port, whereby products of premix combustion can suppress the production of NOx by vitiating a combustion air portion of the process air before the combustion air portion combusts with fuel injected from the burner port.
4 more elements
A method comprising:
- providing material to be processed at an elevated temperature;
- moving the material through a rotary kiln having an inlet end configured to receive material to be processed and an outlet end configured to discharge processed material;
- injecting fuel from a burner port into the rotary kiln;
- driving a stream of process air through the rotary kiln to provide air for processing material moving through the rotary kiln, and to provide combustion air for fuel injected from the burner;
- forming a premix of fuel gas and air;
- and
- injecting the premix into the stream of process air beside the burner port, whereby products of premix combustion can suppress the production of NOx by vitiating a combustion air portion of the process air before the combustion air portion combusts with fuel injected from the burner port.
4 more elements
A method of injecting reactants for combustion in a furnace including a rotary kiln and a burner having a port for injecting fuel into a stream of process air flowing into and through the rotary kiln, the method comprising:
- forming a premix of fuel gas and air;
- and
- injecting the premix into the stream of process air, with the premix being injected in the configuration of a tubular stream surrounding the burner port, whereby products of premix combustion can suppress the production of NOx by forming a tubular region of vitiation through which a combustion air portion of the process air can flow before combusting with fuel injected from the burner port.
A method of injecting reactants for combustion in a furnace including a rotary kiln and a burner having a port for injecting fuel into a stream of process air flowing into and through the rotary kiln, the method comprising:
- forming a premix of fuel gas and air;
- and
- injecting the premix into the stream of process air, with the premix being injected in the configuration of an arcuate stream extending partially around the burner port, whereby products of premix combustion can suppress the production of NOx by forming an arcuate region of vitiation through which a combustion air portion of the process air can flow before combusting with fuel injected from the burner port.
A method comprising:
- providing material to be processed at an elevated temperature;
- moving the material through a rotary kiln having an inlet end configured to receive material to be processed and an outlet end configured to discharge processed material;
- injecting fuel from a burner port into the rotary kiln;
- driving a stream of process air through the rotary kiln to provide air for processing the material moving through the rotary kiln, and to provide combustion air for fuel injected from the burner;
- and
- suppressing the production of NOx by vitiating a combustion air portion of the process air before the combustion air portion combusts with fuel injected from the burner port.
3 more elements
Dependencies are inferred from the claim text.