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利用自主搭建的膜分离CO_2模拟实验台,模拟实际燃煤湿法脱硫净烟气环境,研究了自制聚酰亚胺(PI)中空纤维膜分离CO_2的性能。考察渗余侧气体流量、分离压力和烟气温度对膜分离CO_2性能的影响;研究PI中空纤维膜在含有燃煤飞灰细颗粒物的脱硫烟气条件下的分离性能;此外,利用原子力显微镜(AFM)和扫描电镜(SEM)探究了燃煤飞灰细颗粒物在PI中空纤维膜上的吸附和沉积,及其对分离膜微结构的影响。结果表明,渗余侧气体流量增加,分离压力增加及升高操作温度均可提高PI中空纤维膜对CO_2的分离性能;燃煤飞灰细颗粒物存在时,膜分离CO_2的性能明显下降,PI中空纤维膜的分离因子和渗透速率均有不同程度减少;在长时间与飞灰接触的情况下,PI中空纤维膜表面被大量的细颗粒附着,其表面形貌及微结构受到严重破坏,导致膜的有效接触面积减小,传质阻力增加。
The CO 2 simulation experiment bench was established by using self-made membrane to simulate the net flue gas desulfurization environment of coal-fired wet desulfurization. The performance of self-made polyimide hollow fiber membrane was studied. The effects of gas flow on retentate side, separation pressure and flue gas temperature on the performance of CO 2 membrane separation were investigated. The separation performance of PI hollow fiber membrane under desulfurization flue gas containing fine particles of coal-fired fly ash was investigated. In addition, AFM) and scanning electron microscopy (SEM) were used to investigate the adsorption and deposition of fine particles of coal-fired fly ash on the PI hollow fiber membrane and its effect on the microstructure of the separation membrane. The results showed that the gas flow rate on the retentate side increased, the separation pressure increased and the operating temperature increased, the separation performance of PI hollow fiber membrane could be improved. The performance of membrane separation CO_2 decreased obviously when fine particles of coal-fired fly ash were present. The separation factor and permeation rate of fiber membrane decreased to different extents; in the case of prolonged contact with fly ash, the surface of PI hollow fiber membrane was attached with a large number of fine particles, the surface morphology and microstructure were severely damaged, The effective contact area decreases, mass transfer resistance increases.