Combustion Engineering, Inc.

Alstom Technology Limited

General Electric Technology Gmbh

Todd D Hellewell

Mitchell B Cohen

Richard E Donais

David P Towle

Robert D Lewis

Srivats Srinivasachar

David K Anderson

Michael S McCartney

Majed A Toqan

Paul D Kuczma

Richard C LaFlesh

Michael J Rini

Milton A Fong

Wendell H Mills

Scott L Darling

John Grusha

Galen H Richards

Charles Q Maney

Bryan Walter Mruk

Christopher David Siriani

Patrick L Jennings

Jonathan S Simon

The present application provides a tangentially fired boiler. The tangentially fired boiler may include a combustion chamber and an overfire air system positioned about the combustion chamber. The overfire air system may include a number of overfire air windboxes positioned in a horizontal orientation.

Overfire air system for low nitrogen oxide tangentially fired boiler

A furnace/boiler incorporates a dual injection grid arrangement as per present disclosure. The furnace includes an enclosure having burners projecting through walls of the lower half of the enclosure. The burners inject and ignite a supply of fuel and primary air. The combustion reaction takes place in a combustion chamber. The enclosure walls carry steam generating tubes which absorb radiative heat from the combustion flame to produce steam. The heat is also utilized by radiative/convective super-heater and reheater elements where steam flowing through the radiative/convective super-heater and reheater elements is superheated by the hot gas products of the combustion process. The hot gas combustion products are referred to as the exhaust or flue gas. The combustion products exit the combustion chamber at boiler nose and enter in the boiler/furnace area. The present grid arrangement inject chemicals to control the creating reactants particularly NOx and SOemissions.

Dual injection grid arrangement

A gas mixing device has a plurality of interleaved rows of adjustable louvers. When at least two flowing gas streams are received that are desired to be mixed, the louvers of each row directs the gas streams in a direction different from that of the adjacent rows, mixing the gas streams. When effectively only a single flowing gas stream is received, the louvers are positioned vertically thereby reducing the pressure drop across the gas mixing device.

Enhanced flue gas damper mixing device

A fuel nozzle assembly including a conduit defining a fuel inlet and a fuel outlet and being operable to convey a fuel stream comprising a solid particulate fuel entrained in a fluid. The conduit has a flow area defined by an interior surface of the conduit. A first flow deflector and a second flow deflector extend inwardly from the interior surface. The first flow deflector and the second flow deflector are positioned to disrupt a velocity profile of the flow stream established upstream of the conduit.

Flow deflectors for fuel nozzles

A system includes a selective catalytic reactor and a bypass line. The selective catalytic reactor is located downstream of a furnace that generates flue gases. The selective catalytic reactor reduces nitrogen oxides to nitrogen. The bypass line is in fluid communication with the selective catalytic reactor. The bypass line contacts an input line to the selective catalytic reactor, where the bypass line is adapted to handle a volume of flue gases diverted from the selective catalytic reactor. A first control damper is disposed at an inlet to the selective catalytic reactor; and a second control damper is disposed at an inlet to the bypass line. The first control damper and the second control damper interact to divide the flue gas stream between the selective catalytic reactor and the bypass line in a ratio to reduce the amount of sulfur trioxide released from the system to a desirable value.

Flue gas stream bypass during selective catalytic reduction in a power plant

A nozzle tip [] for a pulverized solid fuel pipe nozzle [] of a pulverized solid fuel-fired furnace includes: a primary air shroud [] having an inlet [] and an outlet [], wherein the inlet [] receives a fuel flow []; and a flow splitter [] disposed within the primary air shroud [], wherein the flow splitter disperses particles in the fuel flow [] to the outlet [] to provide a fuel flow jet which reduces NOx in the pulverized solid fuel-fired furnace. In alternative embodiments, the flow splitter [] may be wedge shaped and extend partially or entirely across the outlet []. In another alternative embodiment, flow splitter [] may be moved forward toward the inlet [] to create a recessed design.

Low NOx nozzle tip for a pulverized solid fuel furnace

A minimum recirculation flame control (MRFC) solid fuel nozzle tip (12) that is suited to being cooperatively associated with a pulverized solid fuel nozzle (34) of a firing system in a pulverized solid fuel-fired furnace (10). The MRFC solid fuel nozzle tip (12) includes a secondary air shroud (46), secondary air shroud support (50) operative for supporting the primary air shroud (48) relative to the secondary air shroud (46), and a splitter plate (52) mounted in supported relation within the primary air shroud (48).

Minimum recirculation flame control (MRFC) pulverized solid fuel nozzle

A control system for a fuel-fired furnace and more specifically the control of the stoichiometric ratio of the combustion process occurring within the furnace of a steam generating power plant. The control system, when so employed, is capable of regulating the distribution of air flow to the combustion process such that the formation of oxides of nitrogen are maintained at acceptable levels. The control system includes in general a stoichiometric subsystem that determines the mass flow rate of air required to maintain the stoichiometric ratio within the combustion process; an override protection subsystem which ensures control precedence of the windbox-to-furnace pressure differential over the stoichiometry subsystem; and an overfire air subsystem that acts to apportion air flow amongst the various levels of overfire air within the boiler.

Control of staged combustion, low NO.sub.x firing systems with single or

An integrated low NO.sub.x tangential firing system (12) that is particularly suited for use with pulverized solid fuel-fired furnaces (10), and a method of operating a pulverized solid fuel-fired furnace (10) equipped with an integrated low NO.sub.x tangential firing system (12). The integrated low NO.sub.x tangential firing system (12) when so employed with a pulverized solid fuel-fired furnace (10) is capable of limiting NO.sub.x emissions therefrom to less than 0.15 lb./10.sup. 6 BTU, while yet maintaining carbon-in-flyash to less than 5% and CO emissions to less than 50 ppm. The integrated low NO.sub.x tangential firing system (12) includes pulverized solid fuel supply means (62), flame attachment pulverized solid fuel nozzle tips (60), concentric firing nozzles, close-coupled overfire air (98,100), and multi-staged separate overfire air (104,106).

Integrated low NO.sub.x tangential firing system

A clustered concentric tangential firing system (12) particularly suited for use in fossil fuel-fired furnaces (10) and a method of operating such furnaces (10) equipped with a clustered concentric tangential firing system (12). The clustered concentric tangential firing system (12) includes a windbox (20), a first cluster of fuel nozzles (38,40) mounted in the windbox (20) and operative for injecting clustered fuel into the furnace (10) so as to create a first fuel-rich zone therewithin, a second cluster of fuel nozzles (68,70) mounted in the windbox (20) and operative for injecting clustered fuel into the furnace (10) so as to create a second fuel-rich zone therewithin, an offset air nozzle (56) mounted in the windbox (20) and operative for injecting offset air into the furnace (10) such that the offset air is directed away from the clustered fuel injected into the furnace (10) and towards the walls of the furnace (10), a close coupled overfire air nozzle (78) mounted in the windbox ( 20) and operative for injecting close coupled overfire air into the furnace (10), and a separated overfire air nozzle (90) mounted in the window (20) and operative for injecting separated overfire air into the furnace (10).

Clustered concentric tangential firing system

A system for pulverizing coal to be burned in a furnace (20), where nearly all of the coarse ash particles are removed from the coal prior to its introduction to the furnace. The system includes a pulverizing mill (10) having a first classifier (12) in its outlet for separating some of the large, heavy particles and returning them to the pulverizer. A second classifier (16) is connected to the first classifier, and includes a curved duct (16) wherein the solid particles being carried in an airstream are thrown outwardly against an outer wall. A skimmer blade (78) extending through the outer wall skims off a percentage of the large, heavy particles, the percentage depending on how much coarse ash the coal stream contains. The rest of the coal particles are conveyed to a furnace and burned therein. The separated large, heavy particles are passed through an ionizer (30) and then through an electrostatic separator (34), where the inorganic particles are separated from the coal particles. The coal particles can then be conveyed to the furnace or sent back to the pulverizer for further grinding.

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Windsor, CT, United States of America

Todd D Hellewell