Is it feasible to introduce air into the flue gas in the coke oven heating system to blunt the combustion air?
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During combustion in the coke oven heating system, the gas channels/air channels of the exhaust gas tray are controlled by solenoid valves in alternate order, allowing flue gas to be mixed in with the combustion air in order to reduce the oxygen content in that air. This reduces the combustion rate, lengthens the flame, and enhances upward heating. But does this method have an effect on reducing the peak flame temperature? Can it achieve the goal of reducing NOx levels? What impact does it have on the flow field resistance of the coke oven combustion system? Please analyze and present your views; if there are relevant practical examples, please include illustrations to support them.
Adjust the primary air volume and reduce the secondary air volume.
The pre-denitration system for low-nitrogen combustion works well and has already been put into use. We are in the process of debugging; this will allow for gas savings, and the NOx levels can be kept below 500, after which an SCR system will be used for nitrogen oxide removal
It can significantly improve upward heating, reduce nitrogen oxides; under the same requirements for quality and output, it allows the operating temperature to be lowered, thereby saving gas. Or maintaining the same standard temperature can increase yield.
Is there another air damper on the coke oven? Secondary air damper?
However, when the coke oven was designed, thorough hydraulic calculations were carried out, and the dimensions of its combustion system were determined based on the amount of exhaust gas generated by the combustion of coke oven gas. Artificially increasing the amount of exhaust gas could theoretically affect the resistance in the combustion system, which in turn might lengthen the flame. At the same time, it’s possible that unburned combustible gases could end up in the exhaust gas, posing a risk of fire or explosion. But what would be the approximate impact on NOX levels? Could you provide data to illustrate this, thank you!
We have been debugging it for a week now, and it is running smoothly. The SCR inlet detector is also under calibration, but the outlet NOx level is below 150.
What is the type of coke oven used in your company? Also, what is the NOx level after front-end treatment but before SCR denitration?
The coke oven model is TJL-4350D, with 2X72 chambers; the current coking time is around 40 hours, and the NOx level is approximately 260-270
We have been in use for about half a year now, and it does show some effects. However, in my opinion, its effectiveness is better when the coke oven is operating at a low load; at high or full load, its impact is limited, as the flow area within the flue must remain constant.
Additional information: TJL-4350D, with a turnover time of 64X2.36 hours; operating temperature of 1295°C. The NOX level before conversion is 440 mg/m3 – this level cannot be achieved at all before the system is put into operation.