What could be the reasons for the high alkalinity of the product from the pressure column in methanol distillation? How to solve it?
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Our plant uses a three-column distillation process for methanol purification; the processes prior to this are shift reaction and low-temperature methanol washing. The current operating load is 110% of the capacity, and the catalysts used in the shift reaction unit are at the end of their useful life. The product from the pressure column in the distillation section has an alkalinity level of 0.0005%. Sometimes the alkalinity needs to be even higher; the amount of alkali added at the pre-treatment tower is 2-3 times that used before. The pH does not increase significantly. I would like to analyze the reason for this, but the analysis laboratory in the company is not capable of detecting trace amounts of ammonia nitrogen in the crude alcohol, so it’s not possible to determine exactly what substance is causing this issue I would like to ask everyone if there are any good methods to address the issue of high alkalinity in distillation.
Was it alkaline or acidic before? What adjustments were made to the process before the increase in alkalinity? Many people currently mistakenly believe that adding more alkali can adjust the pH of a product, but this is not the case. But I’m not sure whether adding more alkali can increase the alkalinity. It is recommended to adjust the amount of alkali to the minimum and increase it gradually; raising the pH value in the pre-treatment tower to above 7 will suffice. Check the quality of the product
The alkalinity of 0.0005% is lower than the national standard of 0.0008%
Our alkalinity is less than 0.0002%
Call me at 15753506807, and I’ll see if our technical staff can help! Yantai Zhi Chu Tian Da Distillation