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During methanol distillation, when fine-tuning the top temperature of the atmospheric pressure column and the reflux ratio, which has a greater impact on the purity of pure methanol and the level of ethanol impurities? In actual production, which one do you prioritize more? Why?
Based on practical production experience, fine-tuning the reflux ratio has a more direct impact on purity. When the ethanol impurity level is too high, it is recommended to adjust the reflux ratio first, because: 1) Increasing the reflux ratio can effectively improve the efficiency of removing ethanol from the tower top ； 2) Temperature adjustment can easily cause fluctuations in tower pressure, which may in turn affect the stability of the entire system. However, the specific parameters need to be determined based on the actual operating conditions of your trays. Could you share the current range of the reflux ratio?
The reflux ratio is indeed a more critical adjustment parameter, and this has been analyzed very well. Two additional practical tips for reference: When making fine adjustments to the temperature of an atmospheric pressure tower, it is recommended to use a step size of 0.5°C. The effect of temperature changes on the ethanol/water azeotrope system is delayed, requiring a longer observation period compared to adjustments to the reflux ratio. If the facility is equipped with a DCS system, a simple predictive model can be developed to relate the reflux ratio to purity; the basic model we use in our factory, created with MATLAB, allows us to predict trends in purity 15 minutes in advance. The specific parameters, however, need to be determined based on the actual operating conditions of your tower. If possible, it is advisable to conduct single-factor experiments first to identify the sensitivity coefficients.
"When the composition becomes heavier, increase the reflux ratio； When the composition becomes lighter, reduce the reflux ratio"