Reasons for the high chloride ion concentration in the catalytic flue gas EDV5000 wet desulfurization process
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When the raw materials for the catalytic unit are not hydrogenated, and the sulfur dioxide concentration at the inlet of the flue gas desulfurization quenching scrubber is high or exceeds the design value, a large amount of alkali must be added to the scrubber’s circulating liquid; as a result, the chloride ion concentration in the slurry at the bottom of the tower and in the circulating liquid of the filtration modules is high. What are the causes and solutions?
The water in the alkaline solution contains chloride ions; as the water evaporates during the circulation process, these chloride ions become concentrated. Generally, when the concentration is 7 to 10 times higher, the waste liquid should be discharged promptly. Solution: Dispose of the waste liquid promptly; no further treatment is required.
An old classmate, if you have time, please take a look at Teacher Gong Wangxin’s book \"Questions and Answers on Flue Gas Desulfurization and Denitrification Technologies in Catalytic Cracking\" to see if it contains what you’re looking for
When the chloride ion concentration in the alkaline solution remains constant, an increase in the amount of alkali added leads to an increase in the chloride ion concentration within the system; even if the discharge volume is not increased, the chloride ion concentration will continue to rise. It is recommended to increase the water replenishment amount, the discharge volume, and the replacement rate.
Increase the discharge from the bottom of the scrubber tower and boost the water supply to it. Although chloride ion concentration can be controlled to some extent through replacement, increased water supply dilutes the circulating fluid in the scrubber tower’s filtration module as well as the circulating fluid at the bottom of the tower, resulting in a decrease in the pH value of these fluids. This in turn leads to an increase in the amount of alkali required for dosing into the filtration module’s tank and at the bottom of the scrubber tower, creating a vicious cycle that causes the chloride ion concentration to rise again. I believe it is better to control the sulfur dioxide concentration in the flue gas at its source (through hydroprocessing of the catalytic feed oil) in order to reduce the amount of alkali needed.