Tar box, air collection duct blocked
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Many new factories have started operations, and due to inadequate management and insufficient equipment, it’s easy for the tar boxes, gas collection ducts, and negative pressure pipes to become blocked. I would like to share some of my insights based on an incident that occurred at my factory when its tar boxes and gas collection ducts became blocked. Half a month after the factory began operating, the tar boxes suddenly became blocked, resulting in a large amount of ammonia leaking out. The management immediately tried to clear the blockages, but it took three days with no progress. Some people thought that the suction power was not sufficient, so they increased it; this led to coal dust filling about one-third of the negative pressure pipes. Such severe blockages occurred within just half a month. The management held a meeting to analyze the causes, which were as follows: 1. The coal mixture was poorly prepared, with particles that were too fine; 2. There were problems with power supply, with frequent power outages; 3. There was no steam available, and the high-pressure ammonia was also affected by the severe blockages. In the end, four points were made on the negative pressure pipes, and each point was cut open to create a one-meter-square opening, allowing workers to enter and clear the blockages. During this process, as the temperature in the carbonization chamber dropped, some of the covers on the rising pipes were removed. At that moment, a large amount of steam rushed into the negative pressure pipes. Initially, it was thought that the steam valve wasn’t closed properly, but after two inspections, it turned out that wasn’t the case. Finally, all the covers on the rising pipes were removed, and the steam subsided. Where did this steam come from? At first, it was thought that the moisture contained in the coal in the carbonization chamber turned into steam and entered the negative pressure pipes after the covers were removed. But since the tar boxes and negative pressure pipes were blocked, no coal had been loaded or any products taken out for four days already. So this theory had to be discarded. But where exactly did this steam come from? This incident took eight days to resolve, and production was halted for eight days as well, resulting in significant losses. Therefore, I believe that new factories must prepare thoroughly in all aspects before starting operations. Workers responsible for the rising pipes should check the liquid level in the gas collection ducts and negative pressure pipes every shift, keeping accurate records. They should also regularly remove any deposits or debris from the tar boxes to ensure smooth flow and prevent similar issues from occurring.
Too **! I wonder if the coal is loaded from the top or the side? What is the slope of the air collection ducts and intake ducts? The source of the steam should be the steam formed from tar and ammonia in the gas collection ducts of the carbonization chamber, as a result of the high-temperature heating after the rising pipe cover is installed.
There’s nothing in the tar box at our factory; I went and tried to retrieve it myself :o. I don’t know what’s going on. Also, may I ask the original poster: where do you monitor the liquid level in the intake pipe? Have you installed any appropriate instruments for that? At our plant, the pressure in the gas collection pipe fluctuates quite significantly at times; we suspect that these fluctuations are caused by a large amount of ammonia present in the intake pipe, which leads to changes in the pressure in the gas collection pipe!
The pressure in the gas collection pipe fluctuates greatly; check whether it is caused by fluctuations in the pressure of the ammonia water pump.
How does high-pressure ammonia affect the pressure in the gas collection pipe?
Is it caused by insufficient pressure of ammonia water?
I’ve read that large coke ovens don’t have circulation holes; why is that?
I believe there could be two reasons for this: 1. The temperature in the space above the furnace is too high, causing the gas to decompose into free carbon and tar, which then combines to form solid residues that block the pipes; 2. The cooling water used to spray raw gas at the start-up stage isn’t preheated to 70–80 degrees, resulting in poor fluidity of the tar inside the collection pipes due to the low temperature, thereby blocking those pipes
The organization of commencement was severely inadequate; what about the commencement plan?； Disorganized management ； The technology is inadequate. It’s a good example of learning*.
http://bbs.hcbbs.com/viewthread.php?tid=183238&extra=page%3D1
Steam is introduced into the tar box to raise the temperature of the ammonia solution, or the height of the tar box is increased
I am familiar with the situation the original poster encountered. In October 2003, when one of the coke ovens at our plant began operation, both the gas collection pipes and the intake pipes became clogged. Some of the company’s bosses deserve to be punished; it’s the result of poor management by people who don’t understand their job. Experience is knowledge; thank you, OP. Last edited by 26722672 on 2009-1-2 14:26]
I am a beginner in the coking industry. In my opinion, it is usually due to the high temperature control in the tar-ammonia water clarification tank and the short settling time (limited processing capacity) that causes the circulating ammonia water containing tar to block the nozzles. Alternatively, if the temperature of the gas collection pipe in your plant and the temperature of the circulating ammonia water are low, as well as the pressure being low, this can also lead to blockages in the gas collection pipe and related areas!
1； It’s because the coal blending fineness is too high, and 2: the temperature in the furnace roof area is too high. 3: Caused by insufficient coal loading in newly commissioned coke ovens. 4: The suction force of the blower is too strong. By handling it in the above manner, the aforementioned issues can be eliminated
The tar boxes in six-meter coke ovens are more prone to clogging; I heard that Liugang came up with a rather simple solution, and it worked quite well
1. The temperature of the gas collection pipe is kept low. 2. Unstable pressure in the gas collection pipe. 3. Insufficient suction force in the intake pipe. 4. The factor of raw material removal may be related to untimely cleaning of the gas collection pipe.