Problem of excessive levels of methanol and ethanol in the finished product
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At present, our company is engaged in the export of methanol. However, the ethanol content in pure methanol is quite high, at 70PPM, and this level fluctuates from time to time. Is there anyone among you who knows how to reduce this ethanol content? Also, is there any inherent relationship between this ethanol level and the synthesis process? Please advise: handshake
This issue has been extensively discussed on forums; you can search for relevant information. There are roughly several methods to reduce ethanol levels: 1. Ensure that the synthesis reaction proceeds well with few side reactions; the ethanol content in crude methanol is already low. 2. Optimize the distillation process by using a large reflux ratio along with side-stream extraction, paying attention to whether the temperature at the point of side-stream extraction corresponds to the highest ethanol concentration. 3. Make sure that the amount of material extracted via side streams is sufficient; the material with a high ethanol content should be sent back to the distillation column for further processing, so as to remove enough fusel oils and prevent ethanol from accumulating in the system
We have encountered this issue before, and it was resolved by increasing the side-stream extraction from the atmospheric distillation column; it’s not a big problem at all! The problem lies in the distillation system; it has little to do with the synthesis system. The selectivity of current methanol synthesis catalysts is quite good. Even in catalysts from lower-quality manufacturers, impurities such as dimethyl ether and paraffin are present in larger amounts, while ethanol is present in much smaller quantities. Therefore, distillation is sufficient to resolve the issue
Increase the reflux flow rate of the atmospheric pressure tower – boost the reflux! The common approach when the distillation product does not meet the specifications is to increase the reflux and raise the heat load!