The COD level in the methanol rainwater system is too high; please provide an analysis
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Methanol wastewater is divided into circulating water waste, concentrated desalinated water and neutralized water, as well as boiler waste. Production is stable, but the drainage levels become unstable and fail to meet standards the day after. No leaks were detected in the system.
This is closely related to your manufacturing processes. If the distillation tower you use does not have any environmental protection measures, that is, it is a wastewater stripping tower, then the main reason is the high methanol content in the liquid at the bottom of the tower. The primary causes for this are excessive reflux flow and low temperature at the bottom of the tower. Sometimes, large fluctuations in the liquid level at the bottom of the tower can also easily result in the discharged wastewater not meeting the required standards. If you have an environmentally friendly stripping tower, then the main problem lies in the tower itself. There are three possible reasons for this: 1. The reflux control in the stripping tower is too high, resulting in a high alcohol content at the bottom of the tower ； 2. The material flow entering the stripping tower is highly variable, resulting in unstable material balance in the tower ； 3. The temperature at the bottom of the stripping tower should be kept low; under normal pressure, it is necessary to ensure that this temperature is at least above 97°C. If none of these three are the case, then it is necessary to consider whether there is a problem with the trays or packing used in the stripping tower. That’s what it says on Baidu{:3_63:}