furnace burners have been developed for a variety of applications in industries
that utilize furnaces for process heating in nonattainment areas. These can be
retrofitted on existing furnaces and purchased with new furnaces. Due to the multiple-burner
configurations on most process furnaces, most low-NOx burner technologies do not
employ flue gas recirculation. They primarily rely on combustion staging technologies
and air/fuel mixing.
The Gas Technology
Institute developed a novel approach to reducing NOx in burners for process heat
furnaces. The technology, known as oscillating combustion, employs a solid-state
ceramic valve to constantly adjust the fuel supply to a burner. In demonstrations
in a variety of process heat applications, the technology reduced NOx emissions
in the 50% range and reduced fuel use due to improved heat transfer.
A listing of
equipment vendors that provide low-NOx burners for process furnaces is shown in
the vendor listing. Specific information about the various types of burners available
can usually be found on the burner vendor's website.
When the fuel flow rate to a burner is oscillated with a special valve
action, it creates oscillating combustion. The oscillation creates successive,
NOx-formation-retarding, fuel-rich and fuel-lean zones within the flame. Heat
transfer from the flame to the load is increased because of more luminous fuel-rich
zones and the breakup of the thermal boundary layer. The increased heat transfer
shortens heat-up times, thereby increasing thermal efficiency.
One of the
major benefits of this technology is that it can be installed as a simple retrofit,
requiring no burner or furnace modification. Furthermore, recent testing has shown
significant fuel savings and NOx emissions reductions.
evaluations of oscillating combustion have been completed. One was on a batch-annealing
furnace in a steel mill. It showed a 2% to 5% fuel savings and a 32% NOx reduction.
Another was on an oxy-fuel-fired glass melter in a fiberglass plant. Fuel savings
of 3% to 4%, oxygen use savings of 10% to 14%, and a NOx reduction of 55% were
documented. In another recent evaluation at a forging facility, fuel savings of
up to 3% and NOx reductions of up to 49% were achieved.
combustion can be applied to many types of furnaces used in the steel industry,
including box annealing, steel reheating, and ladle drying and preheating. In
addition, it is expected to be used widely in glass melters, aluminum melting
furnaces, forging furnaces, metal-melting furnaces, cement and lime kilns, and
other high-temperature furnaces.
Integrated Burner/Fired-Heater Systems
An advanced process heater has been developed for refinery and chemical
plant applications. The technology incorporates a high-efficiency, ultra-low emission
(ULE) integrated process heater system. Four advanced technologies are incorporated:
- ULE smart
- A specially
designed fired heater with enhanced heat recovery, optimized for use with the
ULE burner systems
- An online
process tube temperature sensing and burner control system to enhance heat transfer,
reduce maintenance costs, and increase run lengths
- An adaptive
Predictive Emissions Monitoring System (PEMS) to provide continuous emissions
information without costly continuous emissions monitoring (CEMS) equipment
both natural and forced-draft operation, the ULE burner internally recirculates
furnace flue gases to reduce the rate of NOx formation without compromising efficiency.
Advanced system components (burners, sensors, control systems, and heat exchangers)
are being developed for use in both new and retrofit applications.