How to dehydrate tar
Thread Content
The moisture content in the tar produced by our factory just won’t be reduced; its density is 1.17, its viscosity is 14.73, and the toluene-insoluble content is 20.28. What methods can be used to remove the moisture?
It is generally done through static dehydration; at least 3 storage tanks with a capacity of 5,000 cubic meters or more are required – one for storing the raw materials purchased, one for dehydration, and one for production. This setup is sufficient to ensure an adequate dehydration time. The temperature is usually around 80 degrees, with slow stirring. If the reserve level is insufficient due to inadequate procurement, it will severely affect dehydration; too few storage tanks also have an impact, as there isn’t enough time for dehydration and the appropriate water level for it.
The oil supply from the large ship to the small ship should be even and continuous, and it should be turned off promptly when there is no oil left. The heating for the small boat should be kept on continuously; ammonia water should be promptly poured into the condensate tank, and tar should be evenly and continuously pressed into the tar intermediate tank. When the tar storage tank is at two-thirds full, it should be heated in advance; once the tank is full, the temperature should be raised to 80–90°, after which the mixture should remain at that temperature for more than 4 hours. Then, open the dehydration valves layer by layer to carry out dehydration. At the same time, tar should not be mixed casually. The water-containing tar at the bottom of the tank is promptly sent to the system for re-separation.
This situation also occurred in our workshop during the first half of the year, with a moisture content as high as 23%. Based on experience, it seems that as the moisture content in tar increases, so does the amount of tar toluene insolutes. There are several possible reasons for this: 1. The temperature control in the furnace roof area might be too high, resulting in high-temperature cracking of the benzene rings and aromatic rings in the tar, which alters its composition and consequently its density. 2. Reasonably control the heating temperature of the large tar tank at 85–95°C, and allow it to stand for more than 8 hours to remove water. 3. Maintain a tar level of 360–400 tons and increase the level of the dehydration layer. 4. Mixing tar with low moisture content and high moisture content is prohibited.
Using German super-centrifuges gives good results; it’s just a bit expensive, at 4.5 million RMB per unit
If there is an excess of toluene-insoluble substances, it’s likely that coke dust and coal particles have ended up in the tar, causing the tar to emulsify. Pay attention to the suction force ahead of the machine, as well as any floating coal on the coal cakes. This was mentioned in previous posts; surely this problem no longer exists where you are now. So please tell us how you handle this situation!