Regarding methanol distillation

Product quality issues: I. Issues with the parameters of crude methanol – Regarding this, there is basically nothing we can do; aside from controlling the temperature and pressure during synthesis, there are no other solutions. I. Incomplete pretreatment in the tower – 1. The amount of water added is around 15%, which is essential, as sufficient water ensures complete extraction. When the product quality is poor, adding an appropriate amount helps; beyond 20%, the effect is minimal. 2. If enough alkali is added, the pH at the bottom of the pre-treatment tower can be maintained between 7 and 8, or between 7 and 9 as well – that’s no problem. In addition to preventing corrosion, alkalis can react with certain insoluble organic substances, which helps in the purification of methanol. 3. Top and bottom temperatures of the tower. If it is too low, the removal of light components will not be complete. 4. The liquid recovered from the exhaust gas treatment section cannot be discharged directly into the reflux tank; it is better to send it to a separator so that the light components can be removed from the system directly. II. Issues related to the products of the pressure tower: 1. Reflux – this is almost the only way by which we can control the products of the pressure tower. 2. Temperatures at the top and bottom of the tower. If it’s too high, the heavy components move upward, which is a **problem**! ! III. Products from atmospheric pressure columns 1. Reflux: The amount of reflux determines the temperature; generally, we use reflux as it helps with purification. 2. Side-stream extraction: This is what impressed me the most. Increasing the amount of product extracted does increase the load on the recovery column, but it has only advantages and no disadvantages. More importantly, it is necessary to control the temperature of the material extracted from the side lines, as this allows for the extraction of components that we do not want. Of course, it is first necessary to determine what factors affect the product, identify its relevant physical properties, and then control the temperature to facilitate the extraction of those unwanted components. 3. Temperature: The temperature at the top of the tower must certainly not be allowed to rise too high. As for the bottom of the tower, we prefer it to be higher, as this not only reduces waste but also makes it easier to control the temperature of the side streams. If the steam volume remains constant, the liquid level is the best control method

Bottom stream control in the atmospheric pressure tower: pH: 11–13, specific gravity: >0.996 – that’s sufficient!

Just control the pH and specific gravity well~~~~~

The bottom temperature determines your distillation process； The feed plate temperature indicates the size of your feed ； The temperature difference between the distillation section and the stripping section indicates the amount of impurities ； The tower pressure and the pre-tower pressure difference determine your mass transfer ； The pH value and the extraction water determine the degree of interference from organic substances and impurities ； The reflux ratio and temperature difference determine the water content recovered ；

No, there are also density, chroma, free acid and free base, boiling point, boiling range, and the KMNO4 index