The moisture content at the outlet of the SO2 fan is above 0.3 and this condition persists for an extended period of time
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After fully opening the outlet valve of the drying pump, it was found that the current did not reach its original maximum value – it was about 5 amps lower. The cause was identified as the newly installed energy-saving device; once this device was removed, the current returned to normal, but the moisture level remained around 0.3； Upon inspection, corrosion and perforation were found at the base of the waste discharge pipe at the fan inlet; after repairs, operation returned to normal, but the moisture level measured was still around 0.3 ； During the scheduled maintenance, when the access panel was opened, a hole the size of a dollar coin was found at the top of the tower; this hole could not be seen from the outside during operation. After it was repaired, testing showed that the moisture content remained around 0.3 ； The acid distribution, current, outlet pressure, acid temperature, etc., are all normal; no new leakage points were found during external inspections. Our company operates a sulfuric acid production facility with an annual capacity of 400,000 tons.
Test the concentration of the dry acid. Also, pay attention to the temperature of the flue gas entering the tower, and check whether the acid temperature inside the tower is above the specified limit
Is the drying acid concentration appropriate? Check for leaks before the main fan inlet: what is the temperature of the purification system?
Check the acid temperature and acid concentration. . . .
Since the establishment of our factory, we have always used 96% concentration acid; daily tests show that this value remains stable around 96%. The temperature of the acid entering the drying tower is 40 degrees, while the temperature of the flue gas exiting the electrostatic precipitator is 33 degrees. We have increased the current used in the drying process by 3 amps, and the voltage applied to the electrostatic precipitator has been increased by one level. Tests conducted on October 16 showed a water content of 0.09%, with an acid mist concentration of 0.03%. On the 19th, the water content was 0.16%, but the acid mist concentration remained at 0.06%. During the last maintenance session, the foam collectors were found to be in good condition, and the amount of acid supplied was normal. We are still analyzing the situation to identify any potential issues
At the same time, analyze the moisture levels at the inlet and outlet of the drying tower; if the moisture level at the inlet is too high, drying will not achieve the desired results. In such cases, it is necessary to drain water from the pipeline at the inlet of the drying tower. Furthermore, if the filler is clogged by acidic sludge, reducing the contact area between the airflow and the filler, this will also affect the drying effect; in such cases, the filler needs to be replaced. It is also necessary to check whether there are any leaks in the fan’s piping during the drying process.
Thank you all. We have identified the cause and are working on a solution. The reason is that SO3 in the negative-pressure pipe of the nicotinic acid pump tank enters the drying area and forms acid mist, resulting in excessive acid mist at the fan outlet; now it is planned to route the negative-pressure pipe of the nicotinic acid pump tank to the purification system.
Actually, it’s sufficient to connect it to the gas inlet pipeline of the drying tower
Actually, it’s sufficient to connect it to the gas inlet pipeline of the drying tower. We originally connected it to the gas inlet pipeline of the drying tower anyway