Problems with the extraction of fusel oils in methanol distillation

Really? Does your recovery tower recover the fusel oils that come from the atmospheric distillation column, or does it recover the liquid from the bottom of the atmospheric distillation column? Could you explain the specific process?

The feed for a typical recovery tower is the fusel oil extracted from an atmospheric tower. If this recovery tower is used to treat the bottom liquid from an atmospheric pressure column, its effect is similar to that of increasing the number of plates in that column, but it requires much more energy.

The recovery towers I’ve seen all take in the slurry from atmospheric pressure towers; they basically serve no purpose. They are designed for environmental protection purposes, and their performance parameters are rarely monitored – as long as the slurry is of acceptable quality, that’s sufficient. The extracted product goes directly into the crude alcohol tank

Hello, owner. In our first set of units, both the atmospheric tower and the recovery tower are used for the extraction of fusel oils; after extraction in the atmospheric tower, the recovery tower does not need to be operated. The second set of energy-saving units only uses the recovery tower for extraction. Our situation is similar to yours, but I’m not sure which factory you work for. Could you let me know how your distillation process is set up? If you’re interested, we can get in touch to discuss it further.

Hello everyone: This is the difference between three-column distillation and four-column distillation. The three towers can only be done this way, and the four fruits are done that way; in that case, the four towers lose much of their meaning.

Actually, this can be changed. If, after some time of operation, it is found that the water solubility or oxidizing properties of the product from the atmospheric pressure tower remain substandard, it is possible to switch to using an atmospheric pressure tower, or to design additional extraction points within that tower.

It is inappropriate to arrange for the extraction of fusel oils only in the recovery tower; fusel oils in the distillation system should primarily be extracted in the atmospheric pressure tower. After extraction, they are sent to the recovery tower to have the methanol recovered from them. Moreover, fusel oils can only be extracted from the middle and lower sections of the atmospheric pressure tower, as the temperature at the bottom is different, and most of what is extracted there is wastewater; therefore, extraction at the bottom is not feasible. You can set extraction points in the middle and lower sections of the atmospheric pressure tower

It is essential to extract the middle and heavy components from the middle and lower sections of the atmospheric pressure tower; otherwise, the quality of the products obtained from this tower cannot be guaranteed, and the ethanol content in those products will also be high!

Both the fusel oil recovered from the atmospheric tower of our unit and the wastewater from the atmospheric tower are fed into the recovery tower. The recovery tower is not equipped with a system for extracting fusel oils; given the design of your plant, the recovery tower cannot be considered an environmentally friendly device. In order to prevent fusel oils from accumulating at the bottom of the atmospheric pressure tower, the temperature at the bottom of that tower should be kept low. This, in turn, increases the alcohol content in the wastewater from the atmospheric pressure tower, thereby increasing the load on the recovery tower. Normally, the product obtained from the top of the recovery tower is sent to the crude methanol tank, which results in some methanol being recycled through distillation and thus leads to energy waste. The extraction of fusel oils is generally carried out in the middle and lower sections of an atmospheric pressure column, as the components in fusel oils are mainly substances with temperatures between that of water and methanol, and these substances tend to accumulate in the middle and lower parts of the atmospheric pressure column.

Yes, it’s certain that fusel oil will be extracted; there should also be an outlet for ethanol. What I’m asking is whether what is recovered is the fusel oil from the atmospheric distillation column or the liquid from the reactor – the original poster needs to clarify this