What are the reasons for high moisture content in purified methanol obtained through methanol distillation?
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Dear sea friends, our unit has been experiencing abnormal distillation these days, with high moisture content in the methanol produced. What could be the causes and what are the solutions?
Internal leak cooler； The heavy components rise; increase reflux and reduce steam ； The system is overloaded, with a large pressure difference in the tower ； Wait
What was said upstairs is already very comprehensive!
If increasing the reflux or reducing the steam doesn’t work, you can try reducing the reflux. The pressure difference across the entire tower is high; under temperature differences, reducing the backflow yields results quite quickly.
Or it’s possible to reduce the amount of product extracted, or increase the flow rate of wastewater at the bottom of the tower, reduce steam usage, and increase the reflux rate
The original poster didn’t specify which tower is defective; in the case of a three-tower distillation system, it could be an internal leak in the water cooler of the atmospheric pressure tower, or it could be an internal leak in the crude methanol preheater. These are the more likely possibilities. As long as the operations are carried out according to the specified guidelines, such issues are unlikely to occur. The water coolers in our atmospheric pressure towers leak frequently.
First, it is necessary to check the temperatures entering each tower, as well as the temperatures at the top and bottom of the towers, along with pressure and pressure differences, and compare these values with those under normal conditions in order to determine which part is experiencing a problem. If the pressure difference in the tower is high, it is likely due to a high load or poor mass transfer, excessive steam supply to the reboiler, an excessively high temperature at the bottom of the tower, or too fast upward airflow. In such cases, it is necessary to reduce the amount of steam used, lower the load, decrease the amount of methanol extracted, and increase the reflux ratio. Sometimes, an excessively high reflux ratio for an extended period leads to an increase in the pressure difference across the tower, thereby affecting mass transfer.
Was too much extract water added? If the temperature, pressure, and backflow rate are normal, then the issue of moisture content in the medium should be considered ； The reboiler is leaking, and the cooler is leaking ； Furthermore, the analysis is incorrect!