Acid spraying in the drying cycle tank

Reply to 1# tomcruce: Check that the sampling port is too close to the water addition adjustment port; this leads to intense reactions when a large amount of water is added.

The upper part of the cast-iron sleeve inserted behind the sampling hopper into the dry acid tank may be perforated; it is recommended to stop the operation, empty the acid tank, and conduct an inspection

Reply to 1# tomcruce: The concentrated acid tower likely uses a butterfly-shaped bottom, with the acid returning from the bottom of the tower to the pump tank. If that’s the case, check whether there is a \"T\"-shaped anti-rotation stainless steel plate at the acid outlet at the bottom of your tower If not, it’s either because it wasn’t designed that way initially or due to corrosion; in such cases, steel plates made of 316L or Hastelloy are welded together to form a cross-shaped structure, which is then placed inside the pipe to prevent the acid from rotating. Have you seen the whirlpools in the water? When the rotational flow velocity is high, the gas inside the drying tower is carried into the acid tube and released there, resulting in SO2 escaping from the pump tank. Do you have three towers sharing one tank? How should the breathing tube for the circulation tank be installed? Is it a post-tower process? In the case of a three-tower-one-tank system with a post-tower process, the breathing pipe is usually connected to the inlet of the drying tower. Since the circulation tank is generally under negative pressure, the acid mist generated in the tank as well as the sulfur dioxide released will be drawn into the drying tower. If the breathing pipe of the circulation tank becomes blocked, smoke will emanate from the manhole on the tank, and the area will be filled with acid mist and sulfur dioxide. This requires clearing the breathing tube, as it is usually filled with acidic sludge and sulfates.

The most fundamental problem is likely the blockage of the negative pressure tube; if it is unobstructed, the tank remains in a negative pressure state, so spraying outside is impossible

If it is a post-tower process, check whether there is an issue with the liquid seal

Reply 6# edentree: It is likely caused by a leak in the pump’s suction pipe or a loose seal gasket at the pump outlet

Please check: It seems that the liquid seal for drying and acid return is a bit tight; you may consider reducing the production load or increasing the height of the liquid seal

It is recommended to check whether there are any leaks in the pump casing of the circulating acid pump, etc

The phenomenon of acid spraying is mainly related to pressure issues; excessive pressure in the tank, or a vigorous reaction when water is added, which causes boiling or turbulence inside the tank, can all lead to a small amount of acid being sprayed from the sampling port. Additionally, the elevation of the sampling port location also affects this situation, so it might be advisable to place the sampling port at a higher height.

There is a chance to check the anti-vortex device at the bottom of the tower; if it is damaged, it will allow the gas inside the tower to enter the circulation tank, resulting in acid spraying