Burners and overfire air (OFA)

Combustion & Fuel Systems

Burners

Ignitors

Overfire Air Systems

Combustion Monitoring

Since 1971, B&W has sold low NO_x combustion systems for more than 120,000 MW of generating capacity in both new and retrofit boiler applications. Our low NO_x burner technology has been successfully applied to a broad range of B&W and non-B&W units with varying fuel characteristics and boiler arrangements. We also pioneered the development and application of NO_x ports and air staging for reducing NO_x emissions. Combined with our other technologies, such as burners and selective catalytic reduction systems, overfire air systems are part of an overall NO_x reduction strategy. B&W also offers new and replacement FPS gas, oil and dual fuel igniters, igniter auxiliary equipment, optical and fiber optic flame scanners and control systems for wall-fired and corner-fired boiler applications.

Our combustion solutions include:

DRB-4Z^® burners
AireJet^® burners
DRB-XCL burners
XCL-S^® burners
Overfire air systems
Igniters for gas, oil and dual-fuel

Burners

AireJet^® Low NO_x Burner

B&W engineers designed the AireJet burner with an innovative burner structure — a burner built around a center jet of air, encircled by the fuel stream, and then wrapped in additional combustion air

Pulverized coal-fired boiler applications
Much cleaner burning so it requires less excess air to minimize carbon monoxide (CO) and unburned carbon
Higher boiler efficiency and improved plant heat rate
Excellent flame stability and turndown

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AireJet Burner Mechanical Design Features

Use this quick guide to learn more about the vital parts of the AireJet Burner. Hover over the numbers.

AireJet Burner

Ceramic-Lined Core Elements and Coal Nozzle

Ceramic protection against erosion on core components
inside the coal nozzle and for the coal nozzle

Fixed Spin Vanes in Inner Air Zone

Provides proper swirl to secondary air through inner air zone for ignition

Pitot Grid

Provides a relative indication of secondary air flow to
the main burner assembly using a 30-point
impact/suction device to facilitate balancing air flow
during commissioning

Sleeve Damper Linear Actuator

Adjusts secondary air flow to main burner assembly
for normal operation, light-off, or idle/cooling conditions

Core Air Damper

Controls secondary air flow to center core air zone of burner

DRB-4Z™ Low NO_x Burner

The advanced DRB-4Z is designed to produce lower emissions by featuring a patented transition zone. This zone acts as a buffer between the fuel rich flame core and secondary combustion air streams.

Pulverized coal-fired boiler applications
Superior mechanical reliability and operation
Rugged construction, integrated design
Complete shop assembly – ready for installation
New or retrofit applications

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DRB-4Z Burner Mechanical Design Features

Use this quick guide to learn more about the vital parts of the DRB-4Z Burner. Hover over the numbers.

Low NOx Burner

Linear Actuator

Easily adjusts the main sliding air damper position for
light-off, full-load and idle/cooling

Adjustable Spin Vanes for Outer Air Zone

Provides proper mixing of the secondary air to the end
of the flame

Sliding Linkage

Heavy-duty, non-binding, lever arm movement to control
inner and outer spin vane settings — position is optimized
and fixed during commissioning

Transition Zone Sliding Air Damper

Regulates air to transition zone to optimize emissions

Low NO_x XCL-S^® Burner

This advanced low NO_X burner was developed to achieve superior NO_Xperformance in burner-only applications and in applications using overfire air (OFA) and/or flue gas recirculation (FGR).

Oil and gas boiler applications
Demonstrated NO_x reductions in excess of 90 percent
Demonstrated low NO_x emissions with and without the use of FGR
Superior flame stability and burner turndown
Lower CO emissions
Improved excess air control
On-line adjustability to optimize performance
Low-cost plug-in design
Proven mechanical reliability and operation
Complete shop assembly – ready for installation

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XCL-S Burner Mechanical Design Features

Use this quick guide to learn more about the vital parts of the XCL-S Burner. Hover over the numbers.

XCL-S Burner

Adjustable Hemispherical Gas Spuds

Can be rotated to optimize NO_xreduction and are removable
while the boiler is in service

Burner Support System

Supports the burner and allows for differential expansion

Core Air Damper

Adjusts core air flow to the oil gun or gas spuds for
optimizing combustion

Externally Adjustable Spin Vanes

Provide proper mixing of the secondary air and fuel
(to the end of the flame) – vane position is optimized
and fixed during commissioning

I-Jet Oil Gun

Produces a finer oil spray, reduces particulate and opacity
emissions, minimizes atomizer plugging

Linear Actuator

Easily adjusts the main air sliding damper position for light-off,
full-load and out-of-service cooling

Sliding Air Damper

Adjusts the majority of secondary air flow to the outer air
zone, independent of swirl, to balance air flow among burners
during commissioning

DRB-XCL^® Low NO_x Burner

The DRB-XCL has proven to be the workhorse burner in achieving low NO_x emissions requirements. This burner remains an integral part of achieving optimized NO_x reduction solutions.

Pulverized coal-fired boiler applications
Superior mechanical reliability and operation
Rugged construction, integrated design
Complete shop assembly — ready for installation
New or retrofit applications
Plug-in design

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DRB-XCL Burner Mechanical Design Features

Use this quick guide to learn more about the vital parts of the DRB-XCL. Hover over the numbers.

DRBXCL Burner

Blade Impeller

Beneficial for reducing unburned carbon loss while
still promoting low NO_x emissions

Linear Actuator

Easily adjusts the secondary air sliding damper position for
light-off, fullload and idle/cooling

Pitot Grid

Provides a relative indication of air flow with a 30 point
impact/suction device to balance air flow among burners
during commissioning

Sliding Linkage

Heavy-duty, non-binding, lever arm movement to control
inner and outer spin vanes settings — position is
optimized and fixed during commissioning

Project / case feature item

Combustion Tuning Services using FlameDoctor

Sponsored by Electric Power Research Institute, Inc. (EPRI) and jointly developed by B&W and Oak Ridge National Laboratory, the Flame Doctor^® burner diagnostic system is advanced technology that uses non-linear dynamics to analyze the combustion process with the signals from individual flame scanners.

Benefits of Tuning with Flame Doctor^® Diagnostics

Pinpoints individual burner performance
Reduces emissions
Improves fuel utilization
Improves unit performance
Speeds tuning
Identifies possible burner mechanical issues

Overfire Air Systems (Wall- and Corner-fired Boilers)

Wall-fired air ports

B&W’s dual zone overfire air (OFA) port provides an online means to stage the introduction of air into the combustion process for more effective NO_x control. A sliding sleeve damper allows the regulation of air to each port. Cutting the amount of air supplied to the burners causes a fuel rich/oxygen lean zone to develop; NO_x is suppressed and reduced as it passes through the fuel rich zone. The overfire air system completes the combustion process.

Our dual zone ports simultaneously provide air across the furnace to mix with combustibles well away from the walls, while also supplying air to mix with combustibles in the proximity

of the ports. The heavy-duty design is well suited for extreme conditions of utility boilers. Online adjustability provides the means to fine tune mixing and minimize NO_x emissions.

Corner-fired air ports

Overfire air has proven to very effective in corner-fired boilers originally designed by Combustion Engineering (CE)/Alstom, and is the dominant method of NO_x control with modern systems. We developed our innovative overfire air system for corner-fired boilers using proprietary computational fluid dynamic (CFD) modeling and experience gained from full-scale commercial applications.

B&W’s staged combustion system for corner-fired boilers offers these benefits:

Proven NO_x reduction
Proven design approach with unit-by-unit customization
Maintains boiler thermal performance
Design simplicity for ease of construction and maintenance
Minimal modifications to structural members, sootblower arrangement and platforms
Superior mechanical reliability and operation
Operational flexibility
Rugged design and fabrication for reduced maintenance

Learn more about our Corner-fired overfire Air System solutions