Why does the coke oven continuously produce coke?
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Our company has 3-meter ramming coke ovens; Furnace No. 1 produces coke normally, but Furnace No. 2 continuously generates coke, with a large amount of coke being produced each day, and the coke in this furnace is cooked at the top while remaining uncooked at the bottom. Temperature control is stable; the temperatures of Furnaces 1 and 2 are essentially the same, with a difference within 3°C. Besides temperature, what other factors can cause birth asphyxia? I hope everyone can give some advice! Although the coke was produced under stressful conditions, the quality parameters of coke from Furnaces 1# and 2#—such as ash content, volatile matter, sulfur content, total moisture, fixed carbon, M40, M25, and M10—were all basically within acceptable limits. Here, we check whether the temperature meets the required standards, and all tests show no issues. The company’s two coke ovens were built at different times; it seems they used the same materials, and the manufacturer was the same as well. The iron components of the coke ovens are not identical; the construction of Oven No. 1 took 1 year longer than that of Oven No. 2. Currently, coke is being produced in Oven No. 2. Before last year, the temperatures in these coke ovens were high enough to prevent the formation of defects in the coke. However, after the standard temperatures in the coke ovens were reduced starting at the end of 2008, differences in the quality of coke produced by the two ovens began to appear. Now, the temperatures are 40°C lower compared to before. Let’s analyze it again! Last edited by Wind Graceful and fluid on 2009-3-17 08:06]
Please indicate whether it is localized charring or widespread charring
I think we should start from the following aspects: 1. The rationality of setting the standard temperature; 2. Whether the air excess coefficient is too high, resulting in poor heating at the upper part and thus a short flame; 3. Whether the temperature at the burner section is normal; 4. The uniformity across different rows; 5. The specifications of the coal used as a blend
Usually, we only check the furnace temperature, but there are exceptions in some cases. A coking plant in the southwest encountered a situation similar to that described by the original poster, due to differences in the thermal conductivity of the silica bricks used in the two coke ovens; as a result, different standard temperatures had to be applied to those two ovens. I wonder if the owner’s two coke ovens were built at the same time, and whether the silica bricks are from the same batch and manufactured by the same manufacturer.
It can be assumed with certainty that it’s a temperature issue; by checking the horizontal arrangement, the burner, the space above the furnace, the roof storage area, the temperature in the small flue, and comparing these values with those of the other furnace, the problem can be identified.
The poster should check at which part the carbonization occurs. If the lower part is fully cooked while the upper part remains uncooked, then the air coefficient should be examined as well as the flame height. If carbonization occurs at the burner tip, it may be due to improper control of the burner tip’s temperature; if it occurs in certain carbonization chambers, it is likely due to improper temperature control in those specific chambers. If both furnaces were built around the same time, using the same materials and by the same company, and if the coal used in both plants is the same, then the problem is almost certainly related to temperature.
I agree that points 2, 3, and 4 are more likely to be correct. As the other furnace produces coke normally in point 1, this indicates that the standard temperature setting is reasonable. If the coal mixture used is abnormal in point 5, it’s impossible for only one furnace to produce coke.
Check whether the heating schedule is reasonable； Check whether there are any human-induced factors affecting furnace temperature control
If the operating conditions are basically the same, I estimate the reason lies in the initial construction. Many coking enterprises have their coke ovens built at different times, and the materials used may vary, which could lead to the problems mentioned on page 4.
Jiao Sheng can increase the standard temperature of Furnace No. 2. It might be that the thermal conductivity of the silica bricks used in the two furnaces is not consistent! Just a question: could you provide the quality of coke for each of the two furnaces separately?
This is because the temperature is not properly controlled, or the maintenance of the coke oven is inadequate, resulting in various parameters not meeting the required standards
Although the coke was produced under stressful conditions, the quality parameters of coke from Furnaces 1# and 2#—such as ash content, volatile matter, sulfur content, total moisture, fixed carbon, M40, M25, and M10—were all basically within acceptable limits. Here, we check whether the temperature meets the required standards, and all tests show no issues. The company’s two coke ovens were built at different times; it seems they used the same materials, and the manufacturer was the same as well. The iron components of the coke ovens are not identical; the construction of Oven No. 1 took 1 year longer than that of Oven No. 2. Currently, coke is being produced in Oven No. 2. Before last year, the temperatures in these coke ovens were high enough to prevent the formation of defects in the coke. However, after the standard temperatures in the coke ovens were reduced starting at the end of 2008, differences in the quality of coke produced by the two ovens began to appear. Now, the temperatures are 40°C lower compared to before. Let’s analyze it again! Last edited by Wind Graceful and elegant in movement on 2009-3-16 17:20]
For the two furnaces, different standard temperatures need to be set, and we face this issue as well: when the temperature rises, the coke is cooked
The performance parameters of silicon bricks from different batches may vary. With the same coke oven temperature but different thermal conductivity, insufficient heat may be available for heating the coke cake, which could result in uncooked coke. Additionally, the flame conditions in the flue also have an impact. Have you measured the temperature difference at the center of the coke cake? Excessive temperature differences can also cause coking. Each specific issue needs to be analyzed individually; since the areas where coking occurs vary, the factors to consider also differ. This is just my personal opinion, for reference only.
I personally agree with this view, as the original poster mentioned that the temperatures are similar; it’s likely that this doesn’t apply only to straight-line movements. In the coking plant where I work, there is a situation where two coke ovens were not built at the same time, and although they belong to the same oven set, the standard temperatures differ by 15 degrees. Therefore, the establishment of standard temperatures should take actual conditions into account; the core temperature of the coke cakes could be considered as a factor. Moreover, the original poster said that the temperature difference is only three degrees, which is generally considered abnormal, and it’s necessary to consider human factors. It is recommended to improve the management of the temperature measurement process.
I am extremely grateful to all my friends for their answers; they have taught me a lot, and this knowledge is very useful to me
I took a look at everyone’s opinions; the analyses were quite detailed. Let me add one more thing: the original poster already mentioned that it’s similar to a coke oven, with roughly the same temperature and the same type of coal being used. But one thing that is definitely different is the amount of coal loaded in. Especially in rammed coke ovens, if the height of the coal cakes loaded varies, for example in a rammed coke oven with a height of 4.3 meters, it is generally required that the loading height of the coal cakes be 4.1 meters; if any particular area exceeds 4.1 meters in height, under the same temperature conditions, there is a greater likelihood that coke will be produced in that area.
1. Are the models of the ramming machines for the two furnaces the same? It is possible to check the ramming density. 2. Are the temperature and pressure control settings the same for the two furnaces?
In the case of coke, the upper part cooks first while the lower part does so later. I think that: 1. There is a problem with the heating from above; check whether the suction force is appropriate； 2. If it is a dual gas collection tank, it may be that the pressures in the tanks on the machine side and the coke side are not appropriate, and ammonia is carried in as the raw coal gas passes through ；
It is possible to measure the temperature in the furnace top space and the temperature at the center of the coke cake, in order to establish new standard temperatures. By measuring the pressure at the sight hole, new standards for suction force and roof accumulation suction force are established.
I think there’s a problem with the upward heating. When you say that the temperatures of the two coke ovens don’t differ much, you’re referring to the direct flame temperature, that is, the temperature at the bottom of the vertical flue, which remains relatively constant. If food is cooked in Furnace #2, it indicates that the temperature at the upper part of its combustion chamber is lower than that of Furnace #1. Please conduct a precise measurement, OP.