Wet flue gas desulfurization PH control
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Our company produces sulfuric acid; pure ammonia is added to the bottom of the tail suction tower (where there is circulating liquid), in both gas and liquid phases. I am now trying to adjust the amount of ammonia added for PH or exhaust emission concentration control, but the control is not very effective – there are significant delays and large fluctuations. Does anyone have any good processes or control solutions? Please give me some advice!
For ammonia-based desulfurization, it’s not very effective to control the amount of ammonia added using exhaust gas; controlling the ammonia input by adjusting the pH of the slurry should work. I’m not familiar with your company’s manufacturing processes; excessive ammonia levels can have an impact on the subsequent equipment.
This post was last edited by qugd on 2017-4-23 at 21:47. A few days ago there was a post in response to a question from a member regarding pH control; perhaps it will be useful to you? http://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1761788 Using a packed tower for absorption might yield better results. Additionally, it is difficult to control the process of neutralizing acid with ammonia, as ammonia is a weak base; after absorbing a certain amount of acid (when there isn’t an excess of acid), a buffer solution is formed, and in this case the pH changes little as more acid is absorbed. However, if too much ammonia is used for neutralization, it can cause a significant jump in the pH value. This requires examining the control of pH value during absorption based on actual process variations and equipment conditions.
The pH control shouldn’t experience such large fluctuations, right? After all, there are dozens of tons of water stored at the bottom of the tower, and neutralization should be a slow process; it’s impossible for there to be such large swings.