⇔ Airflow and flue gas flow is slightly lower or about the same. Natural gas boilers operate at lower excess air (O2) and a different airflow requirement for stoichiometric combustion. Coal fired boilers normally operate with 3-3.5% O2 (about 20% excess air). Whereas natural gas boilers normally operate at 1-1.5% O2 (about 7% excess air).? Steam and exit gas temperatures
from natural gas-fired boilers are flue gas recirculation (FGR) and low NOx burners. In an FGR system, a portion of the flue gas is recycled from the stack to the burner windbox. Upon entering the windbox, the recirculated gas is mixed with combustion air prior to being fed to the burner. The recycled flue gas
Flue Gas Recirculation. Flue gas recirculation, or FGR, is the most effective method of reducing NOx emission from industrial boilers with inputs below 100 MMBtu/hr. FGR entails recirculating a portion of relatively cool exhaust gases back into the combustion process in order to lower the flame temperature and reduce NOx formation.
Adapting Boilers to Utilize Landfill Gas: An
(inert) gas in LFG is equivalent to the inert gas entering a boiler when about six percent of the flue gas is recirculated to the boiler. Flue Gas Recirculation (FGR) is a widely applied technique for reducing nitrogen oxide (NOx) emissions from natural gas-fired industrial and commercial boilers,
33 rows · Flue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for …
Sep 26, 2018 · Natural gas boilers with outputs typically between 500kW and 32MW provide a good opportunity for flue gas recirculation (FGR) (Source: Bosch)