Control of nitrogen oxide and sulfur dioxide levels in furnace flue gases
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Recently, two sets of online monitoring and analysis instruments were installed in the furnace of this facility, enabling real-time detection of the levels of nitrogen oxides and sulfur dioxide in the flue gases. I would be very grateful if any experienced colleagues could provide guidance by analyzing the causes of the formation of nitrogen oxides and sulfur dioxide as well as the methods for controlling them; any reference materials available would be even more appreciated.
We are a paraffin oil hydrorefining unit. When the sulfur dioxide level detected by the on-line instruments exceeds the limit, samples must first be taken from the lean gas and dry gas in the desulfurization tower, as well as from the amine solution used for desulfurization. Samples of the dry gas and lean gas from our own unit, along with those from upstream and downstream units, are also taken. Once the problem is identified, the amount of amine solution used can be increased; however, if the sulfur dioxide level still rises even after increasing this amount, then the lean gas must be directed to the flare. The dry gas fraction from adjacent units can also be used to improve one’s own unit for desulfurization.
There is detailed information on desulfurization and denitrification, as well as their causes, available on forums; you can search for it.
Adjust the air volume of the combustion furnace, as well as control the quality of the fuel.
Sulfur dioxide comes from the fuel, while nitrogen oxides originate partly from the fuel and partly from the reaction between nitrogen and oxygen at high temperatures
The generation of SO2 is related to the components in the fuel, while the formation of NOx is determined by both the fuel and the burner used. NOx is primarily produced in the areas of high temperature resulting from fuel combustion; controlling the temperature in these high-temperature areas of the burner can reduce the amount of NOx generated
SO2 can only be reduced by lowering the sulfur content in the fuel gas; otherwise, desulfurization of the flue gas is required； To eliminate the out-of-stock situation, it’s sufficient to reduce the furnace temperature below 1000°C; this parameter should not exceed that value. However, the process requirements might not be met, so additional equipment for eliminating out-of-stock situations would be necessary