Seeking advice on the adjustment of the heating furnace
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I would like those experts in furnaces within the refining industry to tell us what the optimal values are for the negative pressure and oxygen content in heating furnaces. Is there any difference in negative pressure between the radiant section and the convection section?
The negative pressure in the heating furnace is generally maintained at -20 to -40 Pa. The oxygen content is controlled at 1.5 to 2.5 when burning gas (this is the value displayed on the instrument, representing the excess air oxygen content), and at 2 to 4 when burning oil； The negative pressure difference between the radiation chamber and the convection chamber is not significant, generally around 10–20 Pa; it mainly depends on the negative pressure level of the furnace that you control.
In my position, the furnace is fueled by gas, and the negative pressure level is usually around -100. If this value exceeds -50, that is, if it falls within the range of 0 to -50, the flame inside the furnace turns dark red and becomes very unstable. The amount of air entering the furnace is already sufficient; I would like to know what could be the cause of this issue
In our facility, the negative pressure of the heating furnace is maintained at -20 to -50 PA, while the oxygen content is kept between 3% and 5%.
I think, for a negative-pressure furnace, the negative pressure simply refers to the suction force of the furnace; its magnitude just needs to be sufficient to draw away the waste gases. If the color of the flame is incorrect, there is definitely an issue with the air supply. Check whether there are any changes in the properties of your fuel, and also consider whether the amount of air supplied is appropriate
Is there a more in-depth analysis available? Thank you
1. It is important to know whether your heating furnace operates with top combustion or bottom combustion. 2. Our hydrogen production facility uses a top-combustion type of furnace, equipped with 80 burners; the negative pressure in the furnace chamber is usually maintained at around -120 Pa, while the acceptable range in the workshop is -50 to -200 Pa. An oxygen content of no more than 7% is sufficient. 3. The hydrogen heating furnace is of bottom-firing type, equipped with 60 burners; it maintains a negative pressure of around -50, with an oxygen content between 3 and 6
The large negative pressure control range of the top-fired furnace in dry gas hydrogen production units is due to the fact that the main heat source is the desorbed gas, which is not very stable; as a result, the oxygen content and the negative pressure also have a wide range of values. The fuel gas for the hydrogenation furnace comes from the pipeline network and is quite stable; its pressure is generally maintained between -20 and -40 in negative terms, while the oxygen content is around 3. The dark red color of the flame may be related to the fuel gas.
Is it the fuel pressure control that causes the flame to drift and spread? How about trying to increase the pressure a bit?
The flame spreading out is caused by low negative pressure and weak suction in your furnace; adjusting the air valves and flue dampers should resolve the issue. If that doesn’t work, you’ll need to use a soot blower to clean the convection chamber – it’s possible that a blockage in the convection chamber is responsible for the low negative pressure in the furnace. This is just my opinion; please don’t take it personally.
Perform different operations depending on the furnace