In wet flue gas desulfurization in thermal power plants, what is limestone passivation?
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In the wet flue gas desulfurization process in thermal power plants, when the pH value of the slurry in the absorption tower is low, the solution contains large amounts of calcium sulfite. In such cases, if there is a layer on the surface of the limestone with a higher pH value, the crystallization of calcium sulfite causes the limestone to become passivated. Could someone please explain in detail what limestone passivation is, and what the effects of it are after passivation occurs?
Limestone_gypsum flue gas desulfurization: the impact of pH value on the desulfurization efficiency http://www.docin.com/p-8101166.html
The so-called passivation refers to the formation of a tough shell after calcium sulfite crystallizes, which prevents further oxidation reactions from occurring. That's all
This post was last edited by yc125 on 2010-5-27 09:13. As mentioned above, passivation involves the formation of a crystalline layer on the surface of limestone, which prevents further reactions; it’s not an oxidation reaction but rather an absorption reaction – specifically, limestone’s absorption of SO2. You might also want to take a look at the article from the first comment; it’s really good. However, since it’s in PDF format, I can’t copy it for you. You can go to the address provided on the 1st floor to take a look; it’s also available in the forum, so you can search for it