What are the reasons for the unsatisfactory water solubility of pure methanol product? How should it be avoided?

Reason: ① High content of higher alcohols or paraffins in crude methanol； ②In a pressurized or atmospheric distillation column, if the reflux ratio is set too low, the heavier components move upward within the column and exit along with the product from the top of the column ； ③The amount of heating steam supplied to the reboiler of the pressurized distillation column is too high, resulting in fog entrainment or flooding in either the pressurized distillation column or the atmospheric distillation column ； ④Incomplete removal of alkanes in the pre-distillation tower ； ⑤The amount of fusel oil obtained from the side stream of the atmospheric distillation tower is low. Solutions: ① Control the operating temperature of the synthesis tower properly. ②Increase the reflux ratio. ③Reduce the reboiler steam volume. ④Control the operating temperatures of the pre-tower condenser and the expansion gas cooler. ⑤Strictly control the extraction of fusel oils.

(1) Improper pretreatment in the tower resulted in some alkanes that form azeotropes with methanol being carried over into the product, affecting its water solubility. Treatment measure: Adjust the amount of extraction water appropriately based on the quality of crude methanol, and remove alkane impurities through extraction. Control the pre-column condensation temperature to enable the light components to be discharged from the system smoothly. (2) Improper treatment in the main column results in the heavy components entering the product, affecting its water solubility. Countermeasures: Strictly control the operating conditions inside the tower; by adjusting the heat load and reflux rate, maintain an appropriate temperature on the sensitive plate to prevent the upward movement of heavier components

The excessive impurities in pure methanol result in it failing the water solubility test! Try adding some extraction water to the tower!

Try increasing the temperature at the top of the pre-tower and the temperature after secondary cooling, and check whether there are any obstructions in the vent pipeline

During the synthesis process, the composition of the syngas is under control; it is the amount of CO2 that affects the level of moisture, as per the reaction CO2 + 3H2 → CH3OH + H2O. The concentration of CO2 should be kept below 9%, with typical values ranging from 4% to 6%. A certain amount of CO2 is beneficial for the synthesis process, but too high a concentration leads to excessive moisture, which results in waste of raw gas and places additional strain on the distillation process. The reasons for this have been explained clearly by the person above!

During the synthesis process, the composition of the syngas is under control; it is the amount of CO2 that affects the level of moisture, as per the reaction CO2 + 3H2 → CH3OH + H2O. The concentration of CO2 should be kept below 9%, with typical values ranging from 4% to 6%. A certain amount of CO2 is beneficial for the synthesis process, but too high a concentration leads to excessive moisture, which results in waste of raw gas and places additional strain on the distillation process. The reasons for this have been explained clearly by the person above!