Impact of switching resin columns
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This post was last edited by sunjl1981 on 2013-1-6 at 23:49. Here, we usually switch the resin columns around 9:00 a.m. Each time a resin column is switched, the tank temperature decreases while the tank voltage increases; this also affects the density of the anode solution at the outlet of the cell and the flow rate of the cathode solution at that outlet. Please discuss what might be causing this phenomenon What are the solutions? Thank you! # hcbbs
Possible reasons are incomplete displacement with saline in the final step, as well as a long waiting time after regeneration
After the resin tower is regenerated, there is a long waiting period; the temperature inside the tower drops. Before it can be put back into use, the tower is filled with brine for a while, which raises the temperature inside it to some extent. Once it is put into operation, the cold brine inside the tower flows first into the electrolyzer, causing the temperature of the electrolyzer to drop. A lower electrolyzer temperature results in a higher voltage. Many measuring instruments are highly affected by temperature changes; when the temperature varies significantly, the data provided by these instruments may no longer be reliable for reference. It is recommended to increase the saline filling flow rate and time, which can reduce the impact of temperature changes.
There won’t be such a significant impact, because the saltwater is heated before it enters the cell; besides the temperature of the saltwater itself, the catholyte also plays a role in this regard. And does the amount of saltwater entering the system have such a significant impact on the flow rate of saltwater per unit time? Let’s observe it carefully again tomorrow. Hehe. I don’t have any impression of that at the moment.
Causes: 1. Changes in the concentration of the brine fed into the tank; 2. Changes in the temperature of the brine fed into the tank; 3. Changes in the pH value of the brine fed into the tank; 4. Changes in the flow rate of the brine fed into the tank. Solutions: 1. Raise the temperature of the brine fed into the tank; 2. Control the concentration, pH, and flow rate of the brine fed into the tank. 3. If the process used is the Asahi Kasei process, it may be possible to add a storage tank for purified brine – unqualified brine can be recovered during switching, while qualified brine can be stored in this tank, thereby resolving the problem completely. This post was last edited by yzhms on 2009-2-3 at 18:05
We considered this issue before as well, but after observing how things worked out, we realized there was no need to worry about it. The process comes from abroad, and everything that needed to be taken into account has already been addressed; in fact, there was no significant impact.
Check for internal leakage in the reclaimed water valve, the accuracy of the brine replacement flow rate, etc.; with careful inspection, these issues can be easily detected
May I ask if you use a process in which there is no buffer tank behind the resin tower, and the brine flows directly into the electrolyzer?
Solution: Double the saltwater replacement time, and adjust the saltwater replacement flow rate to one-third of the original value. If this does not yield satisfactory results, do not adjust the flow rate; instead, simply double the time and reduce the waiting time
After the resin tower was switched, as the outlet flow rate of the catholyte increased, the laboratory took samples for concentration analysis, and the result showed that the concentration of the alkaline solution remained unchanged.
Half an hour before switching the resin tower, increase the temperature of 153 by 0.5 to 3 degrees; the exact amount depends on how much the temperature of the tank drops. This will reduce the impact of the switch on the tank temperature. If the tank temperature rises, then lower the temperature of 153 again – it still depends on the flexibility of the electrolysis operators… It’s more cost-effective to use more steam rather than more electricity
What battery? There is a preheater for the saltwater entering the tank, which enables automatic adjustment; how can the regeneration of the resin tower lead to a steady decrease in the saltwater level entering the tank?
1. The resin column was not properly purged before switching, resulting in excessive water. This leads to a drop in temperature, large fluctuations in pH, and an impact on the saltwater concentration as well. 2. After switching the resin column, initiate the large-scale circulation to raise the temperature before use. 3. In the past, after switching the resin towers in our company, the electrolysis voltage also changed; subsequent inspections revealed that this was due to inadequate cleaning of the installation sites, significant changes in pH, and variations in saltwater concentration.
If it affects the tank temperature, I think it’s because too much time is spent waiting after filling it with saltwater, or the temperature of the saltwater is too low after filtration. If it affects traffic, I think backwashing alone is not sufficient. Next, consider the accuracy of the control system and the flow meter. There is also the efficiency of centrifugal pumps
It must be the temperature effect; isn’t the temperature of the brine entering the tank controlled?
I was wrong yesterday; there is a buffer tank. It was also found that this not only affects the issues mentioned earlier but also impacts the liquid level in the brine sump, which in turn affects the flow rate of the electrolyzer anode fluid inlet, resulting in a deviation alarm for PCV216
When we identified the cause later on, it turned out that there was a leak in the KV valve of the resin tower; the brine did not enter the resin tower but took a shortcut and went directly into the waste water tank. As a result, after the tower was switched over, the brine was diluted, which led to the aforementioned phenomenon. Thank you all for participating in the discussion! ! !