North American TwinBed ® II Injector
TwinBed® II Air-Cooled LNI Fuel Injectors for Low NOx Operation.
• Direct fuel injection • Very low NOx emissions • Air-cooled LNI fuel injector moderates the nozzle temperature
The Air-Cooled LNI Fuel Injectors were designed for direct fuel injection into the combustion chamber while operating at high furnace temperatures, with or without preheated combustion air. Injecting fuel directly into the chamber, this mode of combustion dilutes the fuel with spent combustion products while simultaneously combusting in a low oxygen environment. Employing the LNI mode of combustion, the moderated flame temperatures results in very low NOx emissions when compared to conventional and air staged combustion modes. While many applications do not require it, there are several operating conditions that will result in insufficient cooling of the alloy nozzle by the fuel only. By actively cooling the nozzle using a low pressure ambient air supply, the Air-Cooled LNI Fuel Injector moderates the nozzle temperature protecting the injector from premature failure. The Air-Cooled LNI Fuel Injector should be used when any of the following conditions are expected: • The furnace operates at or above 2350°F • The fuel to the injector will be shut off for more than 10 minutes or beyond 4:1 turndown while the furnace temperature is at or above 1800°F • The fuel to the injector will be turned down beyond 4:1 while the furnace temperature is at or above 1800°F
COOLING AIR SUPPLY
For applications that are using VFD controlled combustion air fans which turn down to pressures below 6 OSI, it is recommended that the cooling air flow to the injectors be supplied by a separate fan. If cooling air to the injector is interrupted while the furnace temperature is at or above 1800°F it is recommended that the injectors be retracted into the furnace wall as far as possible to prevent overheating.
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