Standard issue regarding the amount of defoamer to be injected?
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Dear seniors, recently there have been pressure fluctuations in the unit’s regeneration tower. Antifoam agents are added from time to time – about once every 10 days, in amounts of around 1 KG each time. After adding the antifoam agent, the operation of the tower improves significantly, and the level of SO2 in the exhaust gases also decreases markedly. However, is there any standard for the amount of antifoam agent to be used? Using too much of it will certainly affect the absorption efficiency of the amine solution, but what is this standard?
It is not recommended to add a defoamer. The cause of foaming in the amine solution should be identified first, and then targeted measures should be taken; otherwise, it will have the opposite effect.
The reason for foaming in the amine solution could be the high pressure difference in our amine filter some time ago; when the filter was opened, it was found that one of its filter bags was damaged, and small particles of activated carbon ended up in the solution. It’s also possible that the amine solution itself is not very stable.
Yes, it is not recommended to add defoamers; they are used only when it is absolutely necessary. From the owner’s description, foaming of the amine solution occurs either because the amine solution itself becomes contaminated, or because there are issues with the operation of your regeneration system, resulting in the decomposition and loss of effectiveness of the amine solution. It is recommended to dilute the required amount of defoamer in foaming liquid or clean cold water at a ratio of 1:5 before use; the suggested dosage is around 0.5–1‰
Could you explain why it’s better not to use a defoamer?
It seems that just a small amount needs to be added; I’m not exactly sure about the specific quantity. However, in our factory, more is added after the liquid is retained
There are many reasons for the foaming of amine solutions, with the main ones being contamination of the amine solution system – such as the presence of oil and hydrocarbons in it, an increase in impurities within the amine solution, and intensified corrosion that leads to excessive levels of heat-stable salts. Therefore, the cause of foaming must be identified first, and corresponding measures taken before the foaming can be eliminated. If foam suppressants are added excessively, on the one hand this will mask the aforementioned problems; on the other hand, foam suppressants usually cause dependence, and just like with drugs, the amount required to be used gradually increases, otherwise they will no longer be effective.
It is not recommended to add defoamers; they are generally used only as a last resort. The main reason for foam formation in the amine solution is contamination of the amine system; identifying the cause and addressing it at its root is the best solution
1-2PPM of the system’s liquid holdup; we have conducted tests, and too high a concentration actually prevents foaming reduction. The levels provided in our studies are around 300PPM; I don’t think such a situation usually occurs.
Learning*, it seems we need to carefully analyze the reasons as well
It is best not to exceed 50 ppm