The 93 acid concentration cannot be maintained
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Acid is produced from smelting flue gas; the gas concentration is around 3%. The process involves two rotations and two absorptions, in a 3+1 configuration. The concentration of the dried acid can only be maintained between 88 and 85 – it cannot be increased. How can this issue be resolved?
Can acid 98 be stabilized? If it can be stabilized, it means the amount of acid in the stream is too low; if that level is also low, it indicates that there is too much water in the system and not enough sulfur, so it’s necessary to increase the gas concentration.
With a gas concentration of 3%, can two rotations and two draws be performed? ? ? What is the concentration of the finished acid? A 93% acid concentration cannot be achieved; the main issue is that the gas concentration is too low, preventing the water balance from being maintained. If the gas concentration remains around 3%, the system may need to be equipped with a pre-drying tower, one purpose being to maintain the system’s level of equilibrium and the other being to produce about 75% pure acid; otherwise, not only will the concentration of the dried acid not increase, but the concentration of the absorbed acid will also not rise.
What is the flue gas temperature at the electric fog outlet? How much moisture is there? Is it above or below the standard?
Find a way to reduce the temperature of the gas entering the drying tower.
It is feasible to use the purification system to lower the temperature of the furnace gas and reduce the moisture carried into the dryer.
Acid 98 can be stabilized; acid 93 is around 89, and the temperature at the inlet of the electrostatic fogger is around 31 degrees
If the electric fog outlet is at 31 degrees, then the concentration of the vapor has to be increased.
1. Low gas concentration is the main reason. 2. The geographical location plays a role; high humidity in the air, which leads to more moisture, also affects the acid concentration.
Reply to 1# Yihuijian: Is the drying cycle acid cooler made of cast iron tubes? It’s definitely difficult to maintain a dry adsorption equilibrium at a 3% concentration during hot and humid seasons! It is recommended to replace the dry acid cooler with a cooler using F4 tubes. Since F4 heat exchange tubes are prone to leakage, it is necessary to isolate the circulating water in the dry tower’s acid cooler, and other anti-corrosion measures such as pipelines lined with PO should be employed.
You’re using flue gas from smelting to produce acid (from gold sulfide ores or low-grade copper ores); with such low gas concentration, the system simply cannot operate properly, and this is also the case in winter (due to the high CO content). It’s time to shut down the plant. Otherwise, the system will be paralyzed, and the consequences would be unimaginable. Drive only after systematic corrective actions have been taken.