Methanol Weekly Topic: How to deal with unsatisfactory water solubility in methanol distillation? 2015.06.15--06.22
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Try increasing the return flow rate; increase it a bit
Water solubility is also known as turbidity. The product quality requirements for pure methanol specify that it can be mixed with water in any proportion without becoming cloudy. If the pure methanol product contains organic impurities that are insoluble or poorly soluble in water, upon addition of water, these impurities precipitate as gel-like particles, resulting in turbidity. The process of water extraction distillation is an important method for separating and removing these impurities. However, the amount of water added generally does not exceed 20% of the crude methanol feed volume. Increasing the water addition amount further will certainly help in removing organic impurities, but it will reduce the production capacity of the pre-distillation tower, increase energy consumption in terms of heat and kinetic energy, and also pose certain difficulties in controlling other process conditions of the tower.
Poor water solubility is generally the result of an excessive amount of by-products generated during synthesis; it tends to be more severe when the catalyst is contaminated or reaches the end of its useful life. Although distillation can be used to address this issue through various methods such as adjusting the reflux ratio, adding extraction water, and improving the recovery of fusel oils, the root cause still lies in the synthesis process itself. . . . . Those with experience can discuss more
The common practice is to increase the venting from the pre-tower
Increase the venting – a lot of valuable substances were lost that way