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
SCC, Inc. Siemens Combustion Controls Industrial Commercial Boiler Gas Burner Control Products.
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.
Commercial & Industrial Boiler Burners using Natural Gas, Oil, and Alternative Fuels. Webster Combustion offers forced draft, powered boiler burners, including designs for high efficiency, high turndown, and low NOx burner configurations for a wide range of boilers, heaters, and many other heating, hot water, and low and high pressure steam applications in both commercial and industrial markets.
Flue Gas Analysis Table Introduction. See Flue Gas Analysis. Operation. Using a Flue Gas Analyzer or any meter designed to measure oxygen or carbon-monoxide, and taking the flue gas temperature and the temperature of the combustion air, the following Table can be used to determine combustion efficiency when operating on natural gas.
Early boilers provided this stream of air, or draught, through the natural action of convection in a chimney connected to the exhaust of the combustion chamber. Since the heated flue gas is less dense than the ambient air surrounding the boiler, the flue gas rises in the chimney, pulling denser, fresh air into the combustion chamber.
A periodic boiler flue-gas analysis is the best indicator that an adequate supply of combustion air exists. This, and any necessary burner adjustments, should be performed by a trained technician with the proper equipment to measure the amount of excess oxygen and/or carbon dioxide and ppm of carbon monoxide.
Example - Oil Combustion and Heat Loss in the Flue Gas. If. the temperature difference between the flue gas leaving a boiler and the ambient supply temperature is 300 o C, and; the carbon dioxide measured in the flue gas is 10% - then, from the diagram above. the flue gas loss can be estimated to approximately 16%.
When fuel is burned in a boiler, it produces flue gas, similar to the exhaust from your car. This gas leaves the combustion chamber and enters the flue passages. The combustion chamber and flue passages (called the heat exchanger) are surrounded by water… the same water that is circulated throughout your home to deliver heat.