How are nitrogen oxides in the flue gas of industrial heating furnaces formed?
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What are nitrogen oxides in the flue gases of industrial heating furnaces? The combustion medium in the heating furnace is dry gas; what components affect nitrogen oxides in the flue gases?
It is recommended to refine the question to facilitate discussion. Industrial heating furnaces have a wide range of applications; it is necessary to specify the components of the dry gas, as well as other factors such as the materials involved. For reference.
This depends on the temperature; it seems that once the temperature reaches a certain level, it becomes easier for it to form
For ordinary dry gas, the methane content is over 95%; under normal conditions, combustion does not produce nitrogen oxides. However, inside the furnace, when the primary and secondary air contribute effectively to combustion, the burning is thorough and the temperature exceeds 800 degrees; at 1500°C in particular, nitrogen oxides are produced – this is something learned in junior high school chemistry, so no further explanation is needed. The air contains nitrogen, and during combustion, almost half of this nitrogen is converted into nitrogen oxides. So, there are three ways to reduce nitrogen oxides: lowering the combustion temperature, reducing the amount of air, and shortening the time at high temperatures. The so-called \"low-nitrogen burners\" commonly available on the market actually work by adjusting the air volume proportionally, carrying out pre-combustion, and splitting the flame. Basically, it’s still a solution involving those three methods
In addition to the main reaction of oxidative combustion between oxygen in the air and the organic components of the fuel, there are also some secondary reactions between nitrogen and oxygen in the air, resulting in the formation of nitrogen oxides. In the nitric acid production process, catalysts are used and operating conditions are optimized to accelerate this reaction.
During the combustion process, the fuel gas oxidizes the nitrogen in the air； Temperatures above 450°C are more effective in reducing nitrogen oxides ；
The use of low-nitrogen nozzles is aimed primarily at reducing the temperature at the center of the flame, by employing multiple nozzles with low-flame temperatures. We’ve been in good control the whole time