How to adjust the primary and secondary air in the auxiliary combustion chamber
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Dear technicians, after selecting the auxiliary combustion chamber, what should be the opening positions of the primary and secondary air valves? How should the primary and secondary air valves be adjusted when raising the temperature?
During ignition, the primary air valve is slightly opened, the secondary air valve is fully opened, and the main air flow rate should be low； As the temperature rises and more gas is introduced, gradually open the primary air valve, being careful not to allow an excessive amount of air that could extinguish the flame; also make sure the furnace does not overheat ； When the primary air valve is already fully open yet the temperature rise requirement has not been met, gradually close the secondary air valve, being careful not to allow the temperatures in the furnace and beneath the main air distribution pipes to exceed safe levels.
Agree with the person above. As an additional point, when adjusting the primary air flow, it is also necessary to take into account the combustion condition of the flame inside the furnace. Similar to heating furnaces, if too much primary air is used, the flame can easily be extinguished, especially when the initial temperature is low ； Conversely, if the amount of primary air is too low, heat cannot be carried away, causing the furnace to overheat, while the temperature of the regenerator rises slowly.
When reducing the amount of secondary air, pay close attention to the temperature of the outer wall, as secondary air serves a protective role; if its amount is reduced too much, it may cause the temperature of the outer wall of the furnace to become too high.
I was on night shift today and working on the auxiliary combustion chamber. At that time, the primary air flow was set at 75% (via the butterfly valve), which caused the furnace temperature to reach 920 degrees, while the outlet temperature was only 350 degrees. The temperature of the regenerator also reached 300 degrees, and it was difficult for it to rise any further. After reducing the secondary air flow by 25%, the furnace temperature began to increase again. Later, I gradually increased the primary air flow by opening the butterfly valve at the fan inlet, but then the furnace temperature started to drop. At that point, all the louvers were already fully open. Since I was worried about causing the furnace to go out, I increased the primary air flow gradually, one degree at a time. May I ask the experts: what should be the ideal level of primary air flow in this situation?
How do I operate the primary and secondary air butterfly valves? On-site and remote operation methods?
The opening degrees of the primary and secondary air determine how the air volume entering the furnace is distributed. If the furnace temperature is high, with the total air volume remaining unchanged, reducing the secondary air amount means increasing the primary air amount, thereby carrying away more heat from the furnace.
Once that furnace is started burning, how do you adjust the auxiliary combustion chamber to raise the temperature? How are the primary and secondary air valves adjusted?