| Electrodialysis as a desalination technology is used during 1,3-propanediol production process in Tian Guan Group. However, there are some problems on electrodialysis desalination applied in 1,3-propanediol production process, such as long operation time, low production yield, serious membrane fouling, and high running costs. So an alternative technology is urgent to improve process effeciency.In this paper, ion exchange was selected as the alternative desalination technology by comparing various desalination methods. Firstly, static experiments were used to investigate the effect of the gel resins and macroporous resin on 1,3-propanediol desalination. Based on the test results of adsorbed acid situation, pH change and elution, the macroporous resin was proposed. Further screening for resin samples from different companies was made by inspecting pH, color value, the conductivity of the material and other indicators, and DO 10, and D363b resins were ultimately determined.Secondly, the process parameters were optimized by evaluation of the dynamic column experiment, and the following parameters were suggested:cation resin and anion resin ratio of 1:1 resin, resin filling height and diameter ratio of 7:1, the feed flow rate was 2 BV/h. Under this condition, the quality of product is ideal, the yield can reach more than 95%, effluent pH is neutral and only contains trace amounts of volatile acetic acid and does not contain corrosive difficult volatile lactic acid, meet the requirements of downstream processing.Finally, based on the optimization results, the pilot scale test was carried out, the results showed that treatment capacity can reach to 8BV, the overall conductivity of effluent is below 2000 us/cm,1,3-propylene glycol and 2,3-butanediol yield is higher than 95%. Apply the new technology in 1,3-PDO production line with an annual output of 1000 tons can save cost of RMB 34.91 yuan per year, which was 31.13% lower than the original. |
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