During the supercritical waterless dyeing, ineffectual separation of dye powders from carbon dioxide often occurs with the gas random motion in the separator, which easily causes gas recontamination in the final separation and recycling period. In this work, a novel separator structure was designed, which greatly helps to enhance the separation efficiency. The flow field characteristics of carbon dioxide in the improved separator were investigated using numerical simulation. Numerical results showed that the regular rotating airflow, quasi-forced vortex and quasi-free vortex of carbon dioxide appear in the separator vessel. The total pressure loss at 200 L/h is 0.98 Pa, which is much smaller than the prototype separator. Furthermore, the enhanced separation efficiency of 9.96 %, 8.82 %, 13.24 % and 13.24 % is obtained for the dye particle sizes from 0.5 µm to 2 μm in the improved separator, which displays a better separation performance. The minimum cycle number which exists at the gas exit is 15654. Separation mechanism of carbon dioxide and dyes in the the supercritical dyeing was also proposed.

在超临界无水染色过程中，由于粉末在分离器中的无规运动，经常会导致染料粉末与二氧化碳的分离不充分，这很容易在最后的分离和再循环阶段引起气体的再污染。在这项工作中，设计了一种新颖的分离器结构，这大大有助于提高分离效率。利用数值模拟研究了改进型分离器中二氧化碳的流场特性。数值结果表明，分离器中出现了规则的旋转气流，准强迫涡旋和准准涡旋。200 L / h的总压力损失为0.98 Pa，比原型分离器小得多。此外，分离效率提高了9.96％，8.82％，13.24％和13。在改进的分离器中，染料粒径从0.5 µm到2μm，可获得24％的分离性能。气体出口处的最小循环数为15654。超临界染色中二氧化碳和染料的分离机理也被提出。