Low-temperature methanol wash drying
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Purpose: After washing and water-based commissioning, before filling the system with methanol, it is necessary to remove any remaining water from the pipes and equipment. Additionally, prior to introducing chemical substances into the system, the water system must be purged with nitrogen in order to reduce corrosion of the equipment and pipes, as well as to meet the requirements regarding oxygen levels set by subsequent processing stages. Technical requirements: A satisfactory level of system drying is indicated when the oxygen content at the analysis sampling point is less than or equal to 0.2% and there is no significant free water present
It’s better to conduct a dew point analysis; that’s better, especially in winter. Our unit performs water-cooled operation in winter, and this is done quite well.
The indicators for dry replacement are: an oxygen content of less than or equal to 0.2%, and a dew point below -30 degrees.
Can it be dried by displacement with methanol to save time?
Upstairs, after methanol displacement drying, what should be done with the methanol that still contains water? Is it sent to the methanol-water separation tower for treatment, or is it discharged outside first and then treated? If it is sent to the methanol-water separation tower for treatment, it will also take a relatively long time, right?
Regarding your question, the recommendation is to use nitrogen directly for drying and purging. First, use nitrogen to remove moisture, thereby preventing oxidation of the inner walls of the methanol circulation system tower (which would cause problems in future operation). After that, continue with the purging process; if the dew point is below -40 degrees Celsius, the drying is successful. At this point, the purging process has also been successful, with the oxygen content definitely below 0.2%.
1. Dry using nitrogen and methanol. 2. Analyze O2