Location for alkali injection in wastewater stripping
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This post was last edited by WoAiMaoMaoRan on July 10, 2016, at 04:03. I’d like to ask everyone: Where is a good place to add alkali? Our unit, located in the raw water tank, seems to have an impact on the desulfurization effect. Can the residence time be ensured in the lower part of the tower? Is the flow directed directly to the trays or through a distributor?
It cannot be injected into the sewage tank, as this will lead to an increase in sulfides in the purified water; it should be injected in the middle to lower part of the stripping tower. We use a 30-layer feed system, so the injection is done at the 12th tray. For injecting alkali, no distributor is needed – it can be poured directly onto the trays or into the downcomers. After entering the tower, it is necessary to extend inwards and bend downward; otherwise, it will cause significant corrosion of the tower walls. Our tower walls suffered from corrosion and leaks, which is why we changed to a design that involves extending inwards and bending downward. Additionally, due to the problem of alkali-induced brittleness, stainless steel pipes should be used at least in the areas where the pipeline enters the tower.
Luoyang Petrochemical Plant has quite a bit of experience; we can exchange ideas with them~~~
In the case of double-tower stripping, it is generally injected in the middle to lower part of the ammonia removal tower, which yields a good effect in removing fixed ammonium salts
Our stripping tower features 49 layers of floating valve trays; we carry out the dosing at layer 35, using diaphragm-type positive displacement pumps. There is a problem: since the alkali is injected onto the trays, and due to the characteristics of diaphragm pumps, water hammer often occurs in the alkali injection lines, leading to frequent leaks. It is recommended to locate the injection point at the downcomer, to ensure that no steam enters the pipelines.