Problem of low temperature in coking flue gas
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Our plant has a 58-Ⅱ type coke oven with 35 years of service. Recently, it has been observed that the temperature in the flue on the machine side is decreasing gradually; today, the temperature in that flue is between 203 and 221°C. In contrast, the temperature in the flue on the coke side remains within normal ranges, at 266 to 275°C (this represents the change in temperature from before to after the exchange). In the previous phase, the temperature on the machine side remained stable at 242–261°C. I would appreciate it if experts could analyze why the temperature in the flue on the machine side has dropped and what solutions might be available I would appreciate your guidance. During this period, the heating regime of the coke oven remained unchanged; the calorific value of the heating gas, the coal blending ratio, and the coking time stayed the same. This post was last edited by liuze78 on 2008-3-14 10:55]
Is there any change in the suction force of the individual flue ducts? Is there water in the flue?
The suction in the individual flues remains unchanged, and there is no water in the flues. The opening degree of the intake door has not changed.
Did there be any changes in the gas flow rate during that period?
Since the aforementioned teachers all said there’s no problem with it, to find out the cause, on one hand you can check the flame on the machine side to see if it’s not burning properly, which could be due to low temperature there. On the other hand, you can also measure the roof storage temperature and the small flue temperature to check if there is a problem in that area. If everything else is fine, then it’s likely that there’s a leak in the flue; check if there are any changes in the suction force in the main flue
If the temperature in the smoke duct on the machine side decreases, first check whether there is anything wrong with the measuring instruments. If nothing is incorrect, consider the following possibilities: A decrease in temperature along with normal heating during production suggests that a large amount of air may have entered the regenerative chamber on the machine side or the control valves. Check whether the horseshoe-shaped temperature sensors located at the top of the chamber are functioning properly； Check whether there is air leakage at the joints of the small flue and the actuators (a torch can be used for this test); improve the sealing, and apply putty to the two prongs of the actuators to see
Thank you all for your advice. It is planned to measure the temperature of the heat storage chamber tomorrow. Check the situation first, and then inspect for leaks in the flue and exhaust dampers.
Check the sealing of the wall! !
It must be caused by a leak in the furnace body.
Let’s start by checking the instruments, and compare the temperatures in the small flue ducts on the machine side. If there are any issues, investigate them; if not, the problem lies in the branch flue ducts, possibly due to insufficient water flow or too low opening angle of the flap valves.
Your furnaces have been in use for a long time; first, you need to measure the temperature of all the small flue ducts on the machine side to determine whether the low temperatures are isolated cases or a general issue. Then, use the methods suggested by those upstairs to find the cause