超临界CO_2喷雾干燥制备乙基纤维素微粒的实验研究

Experimental study on preparation of microparticles by using supercritical CO_2 spray drying

为了扩大喷雾干燥技术在生物物料微粒制备方面的应用,在自行设计的实验台上,以超临界CO2为干燥介质进行了乙基纤维素微粒的制备。研究了喷嘴出口直径、气液比、溶液浓度、温度、压力对微粒粒径及其粒径分布的影响。实验结果表明:改变工艺参数,可在较大范围内调控微粒大小,所制微粒平均粒径为1.07～9.84μm;气液出口为8mm的喷嘴所得微粒粒径比4mm的要小且分布变窄、粒度均匀;气液比对微粒粒径的影响存在一个粒径最大值;高浓度溶液所得微粒粒径比低浓度溶液大,粒径分布略有变宽;随温度升高,微粒粒径增大,高温时所得微粒的粒径分布比低温时宽;随压力增加,微粒粒径减小,高压时所得微粒的粒径分布比低压时略有变窄。

To enlarge the application of spray drying technology on the preparation of biomaterial microparticles, the ethyl cellulose microparticles were prepared by using the supercritical CO_2 as the drying medium on the experimental apparatus designed by the authors. The effects of spray nozzle diameters, mass ratio of gas to liquid, solution concentration, temperature, and pressure on the physical characteristics of ethyl cellulose microparticles were studied. The results showed that the mean size of the microparticles ranging between (1.07) and (9.84) μm could be obtained. The average size of microparticles prepared by the spray nozzle which diameter was 8 mm was smaller than that by the spray nozzle which diameter was 4 mm, and the particle size distribution of microparticle prepared by the former spray nozzle was narrower than that by the latter. With the increasing of mass ratio of gas to liquid, the microparticles that the average size was the biggest could be obtained. The average size of microparticles increase and the particle size distributions enlargement with the increasing of temperature and solution concentration were found, and the results that the average size of microparticles decreases and the particle size distributions reduce with increasing of pressure were also observed.