The issue of excessive nitrogen oxides in flue gas during the startup process of the converter
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Our company has installed online monitoring systems for the flue gas from natural gas-based hydrogen production converters. During operation, the high oxygen content in the flue gas leads to elevated values for the equivalent nitrogen oxide levels in that flue gas. Sirs, have you encountered such a situation? Are there any solutions available?
To address the issue of excessive converted values of nitrogen oxides in flue gas, the following solutions can be considered: 1. Adjust the air intake volume: By adjusting the amount of natural gas supplied, the oxygen content during combustion can be controlled, thereby reducing the formation of nitrogen oxides in the flue gas. 2. Optimize the combustion process: Improve the combustion process in the converter by using advanced combustion technologies and equipment, such as burner improvements and optimized nozzle designs, to ensure complete combustion and reduce the formation of nitrogen oxides. 3. Add flue gas treatment equipment: Install nitrogen oxide treatment devices at the flue gas emission points, such as SCR denitration and catalytic oxidation, to convert nitrogen oxides in the flue gas into harmless substances and ensure that emissions meet the required standards. 4. Regular maintenance and cleaning: Regularly maintain and clean the conversion furnace to ensure the proper operation of the combustion equipment, thereby preventing equipment damage or abnormal combustion that could lead to excessive levels of nitrogen oxides. 5. Monitoring and adjustment of operating parameters: Continuously monitor the nitrogen oxide content in the flue gases, and adjust the parameters based on these measurements in order to optimize the operation of the conversion furnace and prevent excessive levels of nitrogen oxides. The above are some suggested solutions; specific measures need to be analyzed and selected based on the actual situation. It is recommended that you consult professional environmental protection technicians or machinery manufacturers to obtain more detailed and specific solutions. .
It wasn’t taken into account during the design; it’s a problem with the combustion system
This is a common issue; if you are using an old furnace, you cannot increase the temperature according to the prescribed heating curve. At the beginning of the heating process, the blower fan needs to be run at a very low speed, or it can even be turned off entirely； Once the furnace temperature reaches 400°C, the temperature should be increased rapidly by increasing the amount of fuel gas and reducing the air supply, thereby lowering the oxygen content. It turns out that the required heating rate is ≯30°C/h, whereas in this case it could reach 100. If you want to resolve the issue completely, having the design company add a few more sets of bottom burners to balance the heating rate might solve the problem
During startup, the fuel gas flow starts from 0, and there is a requirement for a gradual and steady increase in furnace temperature. Under normal operation, nitrogen oxide levels remain below 50, meeting environmental regulations; however, these levels exceed the limits during the startup phase
It is difficult to control the air volume; if it is too low, there may be flow deviation, resulting in uneven temperature within the furnace