Water content in methanol
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The national standard for the moisture content in methanol specifies 0.1%; is it possible to keep this level at or below 0.05% during normal production? Since methanol is volatile, does the change of season during packaging affect its water content? I’d like to ask all the sea friends!
**The standards specify that the water content in methanol should be below 0.1%. During normal production processes, it can usually be kept below 0.05%. Due to the hygroscopic nature of methanol, seasonal changes can have an impact on its water content, especially during the bottling process. .
Methanol and water do not form an azeotropic system; therefore, in the purification of methanol containing water, it is generally possible to reduce the water content to low levels, such as less than 0.05%. Further reduction of the water content through distillation would significantly increase operating costs, so it is usually sufficient to keep the water content below 0.1%. Since methanol is miscible with water, and under atmospheric conditions the water in the air is absorbed by methanol, this leads to an increase in the water content. Therefore, when storing and transporting methanol, if the sealed pipelines or containers do not provide an adequate barrier against air and the environment, moisture can enter the methanol. In fact, it’s not just the seasonal temperature changes; in the case of methanol storage tanks that are equipped with breather vents, the amount of moisture recovered on a daily basis due to the differences between day and night temperatures is also significant.
Safety considerations also need to be taken into account when storing, right? How could water get in during normal storage?
This post was last edited by qqgd on 2024-10-31 at 15:17. Methanol and water are mutually soluble; when storing methanol, it is difficult to prevent it from coming into contact with the atmosphere. The moisture in the atmosphere (humidity) will dissolve into the methanol, as the chemical potential of moisture in the atmosphere is higher than that in methanol. This process results in an increase in the amount of moisture present in the methanol. Generally, measures to isolate the impact of atmospheric humidity are very costly, so it is extremely difficult to maintain an environment free from humidity for the daily storage of methanol.
Adjusting the operating parameters of the methanol-water separation column can keep the water content at 0.05 or below