| Summary: | 碩士 === 中原大學 === 化學工程研究所 === 104 === Osmotic distillation (OD) recently is considered to be an alternative technology for concentrating liquid foods, which is an isothermal process and can be performed at ambient temperature, being particularly attractive for heat sensitive products. However, OD processes suffer from low flux, which limits their full commercial application. Considering the commercial design to increase membrane area per unit volume and easy to scale-up, hollow fiber modules are more potential for industrial application. In order to establish the basis of its module design, OD with tube-based membrane modules was analyzed experimentally and also gave a comparison with the theoretical simulations. Finally, a preliminary analysis for OD coupled with membrane distillation(MD), called osmotic membrane distillation (OMD), was also studied by simulation.
A comparsion between the OD flux simulated in the study and that measured from literatures was made first and showed both have good consistency. The simulated results also indicated that more than 90 % of mass transport resistance in the OD process is contributed from membrane layer.
Experiments using the self-assembly PVDF tubular membranes module for feed of 16.8 wt% glucose solution and 45 wt % CaCl2 draw solution showed the fluxes increase from 0.6 to 2.3 kg/m2hr as solution temperature operated in the range from 25 to 45℃. As compare the experimental data with simulation, only 0.5~2 % difference was observed. The simulation also showed that the flux increases about 100 % when the draw solution is maintained at 35℃ while the feed temperature of glucose solution is increased from 35 to 45℃ for the so called OMD processes .
Batch experiments for concentrating glucose solution were carried out with 1.4 m2 Liqui-Cel PP module. The feed solution initially of 10.5 wt % glucose and 10 L was concentrated up to 60.5 wt % after 42 hrs operation.
|
|---|
