Why is the free chlorine level high?
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This post was last edited by sunjl1981 on 2013-1-6 23:36. Hello everyone! I heard from one of my former colleagues that the free chlorine level after the dechlorination tower was within normal limits, and so were the vacuum level and pH value; yet after one cycle of brine treatment, the free chlorine level exceeded the acceptable limits I suspect there are two reasons: one is that too much sodium hypochlorite was added, and the other is that the level of chlorate exceeded the limit; when hydrochloric acid is added in the final step, chlorate ions are formed as a result. I wonder which reason everyone thinks is the cause? # hcbbs
This post was last edited by 181128425 on 2009-6-27 08:53. It should be the first scenario; we just need to analyze the brackish water that results from dechlorination.
This post was last edited by 181128425 on 2009-6-27 10:42. Don’t you add sodium sulfite when dechlorinating? If it is added, then the chlorate will also react with sodium sulfite. So, it seems unlikely that the second option will work. Please analyze the free chlorine levels in the dechlorinated brackish water and in the salt water from the pre-reaction tank; it’s possible that the dechlorination process wasn’t thorough enough
OP, your free chlorine level is too high – where was the testing done? What was the measurement result? Generally, the Kaier membrane process requires that the brine entering the Kaier membrane contain 1–3 PPM of free chlorine. After removing the Kaey membrane, sodium hyposulfite was added to adjust it to 0.
1# I and Muziyuan, the poster. You mentioned that the parameters of the dechlorination tower are normal – is it an instrument for online analysis? Instruments have a lag time. Check whether the brine from the dechlorination tower and the Kay membrane contains free chlorine. Also, check if the level of 317 is fluctuating; if there are large fluctuations in 317, it becomes difficult to control the free chlorine level in the dechlorination tower
I’m sorry for not being clear last time; one test was conducted after adding sodium hypochlorite in the dechlorination tower, while the other was done before entering the chelation resin tower. Both tests were carried out simultaneously, both online and through manual analysis, and the results were consistent – they were all on the high side.
Recently, the vacuum level behind the dechlorination tower on our end is normal, the pH value is also normal, and even the ORP reading is normal; however, the free chlorine levels detected by the analysts remain above the acceptable limits. This kind of situation has not occurred before, and we’re not sure what could be causing it.
Recently, the vacuum level after the dechlorination tower is 150, and the pH value is also normal at 11. The ORP reading is above -200; according to the analysts, there is no free chlorine remaining after dechlorination. However, the concentration of brine often exceeds the specified limits. This situation has occurred before as well, and we’re not sure what the cause is. If the chlorate content in saltwater is high, what is the reaction mechanism?
This happens when the chlorate level is high. Adding sodium hypochlorite does not work well when the chlorate level is high.
It is possible to analyze brackish water; our company uses decomposition tanks for this purpose