Ethylene glycol products require further removal of water, methanol, and ethanol
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This post was last edited by xuqinger on 2015-8-10 at 14:36. The ethylene glycol product after distillation still contains 300 ppm of water, 700 ppm of methanol, and 500 ppm of ethanol. What methods can be used to reduce the concentrations of water, methanol, and ethanol to below 50 ppm? Is there a significant price difference between these two purity grades of ethylene glycol products? What grade is the ethylene glycol used for polyesters?
This post was last edited by yjqin1 on 2015-7-20 06:16. Are there molecular sieves with such good performance in practical applications? The order of polarity from highest to lowest for ethylene glycol, water, methanol, and ethanol is: water, ethylene glycol, methanol, ethanol. There is data to prove it. The infinite dilution activity coefficients of water, methanol, and ethanol in ethylene glycol are 0.83, 1.35, and 1.80, respectively. Do molecular sieves have such good resolution and selectivity for these four? The total amount of water, methanol, and ethanol in this solution is only 0.15%.
It seems like this direction is worth considering
I’ve encountered this problem too. Has the original poster found any suitable methods that are commonly used in industry?
Are these three components difficult to separate? There should be no azeotrope, and distillation can solve this issue. Both petrochemical hydrated products and coal-based hydrogenated products can be brought to polyester grade through distillation; there should be no problems, as they are not aldehydes or diols. Even with aldehydes and diols, distillation is no problem; at most, the yield for polyester-grade material will be lower.
I just can’t think of conventional techniques, so I’m trying unconventional ones. Speaking of which, if this project is successful, the costs will be extremely low, and there will be no loss of ethylene glycol either.
Ah! How do I do it? I’m so worried!
I’m not sure what the parameters of your distillation process are; generally, after methanol is removed in the first column, its concentration is not very high. A higher temperature can be used in the second column for removing ethanol, as there’s no need to maintain such a low temperature at the top of that column. Water and ethanol are discharged from the top of the tower. By the time it reaches the three towers, the purity of ethylene glycol is very high.
Distillation is used for all of them. . . Molecular sieves sound quite difficult
There’s a problem with the distillation tower, right? . . 3-column distillation can produce ethylene glycol that meets the national standards for top-quality products; your product meets only the standard quality level, and it is about 1000 yuan cheaper than top-quality products