固液两相流对管式膜超滤过程强化的研究

Study on the Effect of Solid-liquid Two-phase Flow on the Intensification of Tubular Membrane Ultrafiltration Process

采用PVDF管式膜对牛血清蛋白溶液进行错流超滤实验,加入活性炭、陶瓷、PVC等固体粉末形成固液两相流,考察在固液两相流下粉末种类、跨膜压差、膜面流速、料液蛋白浓度及粉末投加量等参数对管式膜超滤过程的影响。实验结果表明,陶瓷粉末因其硬度大,易造成膜面磨损,不适宜作为固相介质。活性炭粉末硬度适宜、廉价易得且较PVC粉末强化效果明显,当牛血清蛋白浓度为100 mg/L时,活性炭粉末(饱和)投加量为2.5 g/L左右效果最佳;跨膜压差越大、料液蛋白浓度越高,固液两相流对超滤过程的强化效果越明显,0.5 MPa时渗透通量可提高84%;增大膜面流速利于提高渗透通量。可见,引入固液两相流能有效减缓浓差极化和膜污染,对管式膜超滤过程强化效果明显,有利于提高膜过滤效率。

Cross-flow ultrafiltration experimentsfor BSA solution were carded out with the PVDF tubular ultrafiltration membrane, and solid powders like activated carbon, cemmicsandPVCformulatedsolid-liquidtwo-phasesflow.Theeffectofpowderkinds, transmembranepressure, membrane surface flow velocity, concentration of feed liquid with B SA and powder dosage on ultrafiltration performance were investigated with solid-liquid two phases. The experimental results showed that, ceramic powders were easy to wear the membrane surface due to its high hardness, which was not suit for the experiment. Compared with PVC powders, activated carbon powders were better for the test, considering its suitable hardness, low cost and the strengthening effect. When the concentration of BSA was 100 mg/L,the intensification effectof mass tmnsferwas best for theexperiment withactivated carbon powders （saturated with BSA） dosage of 2.5 g/L. Besides, the higher TMP and the concentration of BSA of feed liquidwas, the more obvious thestrengthening effect of solid-liquid two- phase flow on ultrafiltration process was. And the permeation fluxwasincreased to 84% at 0.5 MPa,increasing the membrane surface flowveloeitywas good for improving the permeation flux. The results showed that the introduction of solid-liquid two-phase flow could effectively relieve the concentration polarization and membrane pollution, andthe intensification effect of tubular membrane ultrafiltration process was obvious, which was conducive to improve the efficiency of membrane filtration.