Methanol distillation water solubility problem

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This post was last edited by Qingfeng Liushui on 2009-12-9 09:35 In the later stages of use of synthetic catalysts, refined methanol has poor water solubility. The situation is as follows: 1. The device is a natural gas methanol production device. The synthesis tower is a Lurgi uniform temperature type. It is equipped with TOPSOE's MK series catalyst. It is currently in the late stage of catalyst use. The synthesis bed temperature is about 255 degrees Celsius. ； 2. The methanol content at the entrance of the synthesis tower is high, and the synthesis wax formation is serious. ； 3. The distillation system adopts the classic two towers, which are floating valve towers. ； 4. Methanol products have poor water solubility and will appear white and turbid after adding water (1+3). Measures taken and their effects: 1. Increase the reflux ratio of the main tower: The reflow ratio has been increased to about 3.8, and the quality has improved slightly. ； 2. Appropriately lower the temperature of the sensitive board: The sensitive board has dropped to about 80 degrees Celsius, and the quality has improved slightly. ； 3. Increase the heat of the pre-tower, increase the venting volume of the pre-tower, and increase the reflux temperature of the pre-tower and main tower.: Basically no change in quality ； 4. Increase the amount of alkali added: Water solubility has basically no effect ； 5. When the extraction water is added (because it can only be added to the entrance of the pre-tower and cannot be added to the reflux tank), the water solubility of the product will basically remain unchanged. ； 6. Increase the extraction of alcohol from the main tower: Basically no impact. discuss: 1. Is it necessary to add water to dilute methanol? The concentration of synthesized methanol is only 84%. In the past, products without adding water were also good. ； 2. The phenomenon of poor water solubility will occur after the synthesis system is continuously heated several times. ； 3. The sample taken from the reflux tank in the pre-tower becomes very turbid (white like milk) after adding water. ； 4. The filter entering the tower is frequently blocked by paraffin and needs to be cleaned basically every 2 days. I suspect that paraffin (C5-C10 alkanes) cannot be eliminated in the pre-column and forms an azeotrope in the main distillation column and is brought into the product. Most of the measures that can be taken have been tried, but the results are not good. I would like to ask colleagues for their methods and experience in solving this problem.