The secondary voltage for primary electrodeslagging in the purification process drops rapidly
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Our company uses flue gas from bottom-blown lead-zinc smelting to produce sulfuric acid, with an annual output of 72,000 tons. After the mid-year maintenance in July 2018, and starting from early September, the secondary voltage in the electrostatic demisting unit of the purification process experienced a rapid drop. Several times during that period, the operation was halted for inspections inside the electrostatic demister; it was found that there were numerous burly, crystalline formations on the walls of the anode tank, about as thick as a matchstick and 2–3 cm in length. At that time, a large amount of high-pressure water was used for flushing; after the machine was started up, the voltage rose above 50 kV, but after 24 hours the voltage dropped back to 41–43 kV. The current solution is to cut power for defogging during the early shift each day, then rinse for 10–15 minutes; once the operating voltage returns to above 50 kv, it cannot be maintained for more than 24 hours. The cathode wire for electrostatic demisting is a lead-copper alloy. Fluorescence analysis of the acidic sludge that emerged showed 78-80% selenium oxide and 16-18% mercury oxide. Question: Since it is not possible to make better improvements to the raw material flue gas for the time being, how can sulfuric acid address this issue by focusing on purification? It can be related to processes, equipment, or operations – please feel free to offer your guidance.
The purification and washing effect in the front is poor, resulting in a large amount of impurities reaching the electrostatic mist remover.
There are too many aerosols! ! ! ! The voltage of the primary electrostatic fogger can be increased to reduce the amount of aerosols produced by the secondary electrostatic fogger
It’s a bit like the sulfur sublimated from acid produced in our mines! Try to minimize impurities in the manufacturing process
We’re having issues with the primary electric demister; the voltage is too low, and sometimes it drops below 40 KV, which essentially renders the demisting function ineffective.
It is estimated that your setup involves two stages of washing plus electrostatic misting; you can add another washing unit before the electrostatic misting stage, equipped with a foam collector.
At present, the dilute acid is relatively clear; waste water is discharged once a day. With the external temperature currently ranging from 10 to 15°C, the voltage applied in the first-stage electrodeslagging process remains fairly stable, exceeding 50 KV.
Increase the purification efficiency in order to reduce the impurities entering the electrostatic precipitator: 1. Improve the operating performance of the electrostatic precipitator； 2. Reduce the concentration of the dilute acid wash solution to improve the washing effect.
The melting furnace wasn’t properly controlled, resulting in low residual oxygen levels; this led to the generation of large amounts of sublimed sulfur and volatile substances from the ore, which were carried into the acid production and purification system. There was a high dust content there – haven’t you noticed that the heat exchangers are clogged?