Apparatus and method for reducing NO.sub.x , CO and hydrocarbon emissions when burning gaseous fuels
AssigneeRadian Corporation
InventorSteven J. Bortz
Life of this patent
Estimating the term…
Abstract
A two stage rapid mix burner provides apparatus and method which significantly reduce the burner size of a rapid mix burner, and/or the burner pressure drop, while maintaining the rapid mix feature and stability of the basic rapid mix design. The burner can also be easily altered to fit in non-circular geometries, such as a corner or tangential fired boiler. The invention uses a circular basic rapid mix burner located internally of a larger burner which can be non-circular. The inner burner provides the flow of hot gases which stabilizes the outer burner. In effect, the combustion gases produced in the inner burner replace the strong internal recirculation flow generated by the basic RMB as an ignition source for the outer burner flow.
Claims22
A forced draft burner apparatus for burning a gaseous fuel while producing low levels of NO.sub.x, CO and hydrocarbon emissions;
- comprising:
- a cylindrical inner burner having a tubular wall;
- a generally cylindrical body mounted inside the tubular wall of the inner burner;
- an annular flow channel being defined between said body and the inner wall of said tubular section, said channel constituting a throat for oxidant gases, and having a downstream outlet for the inner burner;
- means for supplying oxidant gases to said throat of the inner burner;
- a divergent quarl for said inner burner having its smaller end connected to said outlet of said inner burner, and exiting into a combustion chamber;
- a plurality of curved axial swirl vanes being mounted in said annular flow channel of the inner burner to impart swirl to said oxidant gases flowing downstream in said throat;
- inner burner fuel gas injection means for the inner burner being provided in said annular channel proximate to said swirl vanes for injecting said gas into the flow of oxidant gases at a point upstream of said outlet end in a manner that results in uniform mixing of the fuel and oxidant upstream of the ignition point;
- said fuel gas injection means for said inner burner comprising a plurality of spaced gas injectors each being defined by a gas injection hole and means to feed the gas thereto;
- the ratio of the number of gas injection holes to the transverse cross-sectional area of the annular flow channel of the inner burner being at least 200/ft.sup.2 ;
- an outer burner surrounding at least a portion of said inner burner and including a wall spaced from the outer wall of the inner burner to define an outer burner flow channel having a downstream outlet end for gases provided to said channel;
- means for providing a flow of oxidant into the outer burner flow channel;
- and
- outer burner fuel gas injection means for the outer burner being provided in said outer burner flow channel, upstream of the outer burner outlet end, comprising a plurality of spaced gas injectors, each being defined by a gas ejection hole and means to feed the gas thereto;
- the ratio of the number of gas injection holes to the transverse cross-sectional area of the flow channel of said outer burner being at least 200/ft.sup.2.
Dependencies are inferred from the claim text.