The effect of adding acid on the battery cell
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This post was last edited by sunjl1981 on 2013-1-6 23:36. I saw many teachers discussing that adding acid to the battery affects the tank pressure. I would like to ask whether the amount of acid added will affect the tank pressure? Why? Of course, if too much acid is added and the pH is lower than 2, it will definitely be affected, but will it also be affected if it is adjusted within the normal range? I remember seeing a teacher in Haichuan a few days ago who said it had a great impact. Why? # , , &
After adding acid, control the acidity of the anode inlet and outlet to within the control index.
Adding acid to the battery tank can improve the purity of chlorine. We are using a tank from a chlorine engineering project. I feel that the voltage of the tank does not change with or without adding acid. I don’t know what happens with other tanks. You can experiment with it. Adding acid or not does not affect the tank pressure. The risk is definitely not big.
There are two types of ion membrane processes: acid addition and no acid addition. The details depend on the process. As for the acid addition process, adding an appropriate amount of acid is beneficial to the cell voltage and can reduce the cell voltage.
Acid is added to adjust the pH to 2 to 5. If the pH is too high, OH ions will seep back into the cathode, and the mobility of hydrated sodium ions at the cathode will decrease, resulting in a decrease in current efficiency.
Advantages of adding acid to ion membrane: There are three purposes for adding acid: 1. It is to neutralize the hydroxide radicals reversely osmotic from the cathode, reduce the sediment generated at the anode, and then reduce the amount of sediment deposited on the membrane when water permeates the membrane, thereby achieving the effect of reducing the cell voltage. 2. As the electrolysis proceeds, the chloride ions near the anode plate are consumed the fastest. When the chloride ions near the anode plate are consumed, the concentration difference must be relied on to cause the farther chloride ions to migrate over to keep the anode continuing to generate chlorine. Otherwise, side reactions will increase. Adding acid can slightly increase the chloride ion concentration in the anode area (the effect is obvious for cells with low salt water flow rates). 3. Reduce the loss of chlorine due to dissolution and increase electrolysis efficiency. Disadvantages of adding acid to ion membrane: The operating requirements have increased, and try to avoid excessive addition of acid, otherwise it will lead to the following problems: 1. Increased auxiliary anode corrosion at salt water inlet ； 2. The membrane is acidified and loses its function. ； 3. Calcium and magnesium impurities in the salt water form precipitates in the membrane, destroying the structure of the membrane. From the principle of adding acid to reduce the cell voltage, the amount of acid added will affect the cell voltage. However, judging from the actual operation situation, because the chlorine generated by the anode is partially soluble in salt water, the pH value of the anolyte can be maintained at 3.7 to 5 even without adding acid. The process of depositing sediment on the membrane is slow, so short-term acid cessation has minimal impact on the cell voltage. This post was last edited by alaslxf on 2008-2-2 21:56 ]