How to remove salt deposition and how to prevent it in alkylated circulating alkaline water shell-and-tube heat exchangers?
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The alkylation caustic washing tank’s circulating caustic heat exchanger suffers from salt deposition; currently, the caustic concentration is maintained at 3–8, and the caustic washing temperature is 49 degrees.
Is it scaling or salt deposition? The operating conditions seem to be normal. What is the temperature at the inlet of your heat exchange medium (which is usually alkylation oil)?
Salt crystallization occurs; the inlet temperature on the shell side is around 100 degrees, while low-pressure steam flows through the tube side
Our device also has slight scaling, which might be related to metal ions in the alkaline solution
May I ask how your company solves this problem? We now plan to reduce the alkali concentration to 2%-4%; if it falls below 2%, we will lower the liquid level a bit and then add more alkali. What is the alkali concentration level controlled by your company?
The concentration of the alkaline solution is 4-6%; in fact, the alkaline substance used for correction is 10% concentration. Our company has not taken any measures to address this issue, as the scaling is not severe – it’s only a thin layer. There is basically no scaling inside the heat exchanger. We use octane from external supply units as our heat source, in large quantities, and its temperature is likely lower than that of your steam