Reprocessing method of unqualified refined methanol
Thread Content
Unqualified refined methanol is generally returned to the crude alcohol storage tank for secondary refining. In order to avoid damaging the stability of the distillation system, certain methods must be used when adding pure methanol. For example, sometimes an appropriate amount of water must be added to methanol, or mixed with crude alcohol. However, sometimes the system may still be unstable. I would like to ask everyone in the forum, how do you usually operate the refining of unqualified refined methanol, and what is the effect?
As you said, just return it to the system for distillation. It will only increase the purity of your crude alcohol, and it won't have much impact. Of course, if the amount is large enough to affect your crude alcohol, some parameters may change significantly during operation, but it will not have much impact.
The front system maintains a certain load, and the load is as high as possible to provide enough steam for the distillation system. If there is an auxiliary boiler, the boiler will lift the load. Distillation increases the reflux volume and maintains the original reflux ratio. Of course, the heat of the reboiler must be appropriately increased. For example, the steam reboiler increases the steam volume, the gas reboiler increases the water-to-carbon ratio, etc. If the crude methanol contains a lot of water, you can appropriately reduce the amount of extraction water and drain the water out of the system as soon as possible. ； If the methanol content in the crude methanol is relatively high, the reflux ratio can be appropriately reduced. Maintain heat and material balance throughout the tower. The temperature throughout the tower also needs to be balanced. If the crude methanol contains a lot of acidic substances, add more alkali solution appropriately to keep the low pH value of the pre-distillation tower constant. Operators like it more during this period, and the output has increased a lot, haha.
The distillation system cannot exceed the design load by too much, so as to ensure product quality. Generally, the design load of the distillation system is higher than the load of the previous system, 110: 100, this is generally no problem. The crude methanol produced by synthesis is sent to the flash evaporation tank, and the methanol in the crude methanol tank is also sent to the flash evaporation tank for mixing together. Maintain constant pressure in the flash tank. If the pre-tower is full reflux, the outlet temperature of the tower top water cooler should be appropriately adjusted to be within the control range. The main distillation tower still needs to control the temperature and pressure at the top of the tower.
It depends on what failed you. If you don’t make targeted adjustments and try again, you still won’t pass. There’s nothing else, it’s just that the load on the system is a little higher.