The acid level in the drying tower is extremely high; please conduct an analysis
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Recently, it was found that acid carryover in the drying tower was extremely severe; however, the metal mesh appeared to be in good condition. (This issue started only recently.) The acid distributor used is of the tubular type. In August 2019, due to frequent blockages in the acid distributor, we increased the diameter of the acid distribution holes from 14 mm to 16 mm. Yet no problems with acid carryover occurred until December. It wasn’t until around the beginning of 2020 that it was discovered that a large amount of acid was being released from the first heat exchanger at the fan outlet, and the fan was vibrating severely; the pipe at the fan outlet was also vibrating. The accumulation of acid in the DN1200 mm fan outlet pipe was about 250 mm deep, preventing the fan from operating properly. The drying resistance is 2500 Pa; what causes this?
It is not possible to determine the quality of screen printing fabric simply by visual inspection; a correct assessment can only be made by combining tests such as acid mist testing and the wooden stick test.
The tubular acid separator is clogged; are you using bottom spraying?
1. There is a layer of fiber sandwiched between the metal wires; generally, the fiber has been corroded away. 2. Uneven acid distribution can also lead to excessive acid mist being emitted from the tower. 3. The gas velocity inside the tower also has an impact. 4. For the wire mesh demister, check whether there is any air leakage at the installation joints. For example, whether there are gaps around the tower. It causes a short circuit.
1. There is a layer of fiber sandwiched between the metal wires; generally, the fiber has been corroded away. 2. Uneven acid distribution can also lead to excessive acid mist being emitted from the tower. 3. The gas velocity inside the tower also has an impact. 4. For the wire mesh demister, check whether there is any air leakage at the installation joints. For example, whether there are gaps around the tower. It causes a short circuit.
By turning it on, the blind flange of the acid separation layer can be opened to check whether there are any problems with the acid separation pipe
Uneven acid distribution, high gas flow rates, blockages caused by acidic sludge, damaged mist eliminators, and so on, can all lead to the presence of acid
Reduce the production load and see if any acid is discharged
Check 1. Whether there is any air leakage between the outlet of the drying tower and the blower, which could increase the moisture content in the furnace gas； 2. Is the acid distribution uniform in the acid distribution tube? ； In tubular acid separators, the pressure of the liquid is used to ensure even distribution of the acid. When the holes are enlarged, the reduced pressure will certainly lead to uneven acid distribution. If the holes become blocked, it is necessary to check the partition walls in the circulation tank; the ceramic rings should be located on the side of the return pipe, separated by those partition walls. 3. Is the load too low? A reduced gas velocity can affect the collision effect
An increase in the acid separation pore size leads to a decrease in the acid separation pressure; if the system operates at high gas velocities, this may result in flooding. Page 692 of “Sulfuric Acid Production Technology” provides a detailed explanation of this issue.