【作者】 梁卫华； 王金福； 罗务习； 金涌；

【Author】 LIANG Wei-hua, WANG Jin-fu, LUO Wu-xi, JIN Yong (Department of Chemical Engineering, Tsinghua University, Beijing 100084, China)

【机构】 清华大学化工系；

【摘要】 硅粉是合成有机硅单体(二甲基二氯硅烷)的重要原料,研究硅粉的流化特性具有深厚的工业应用背景。在直径110mn的等径流化床和直径215mm的具有下锥体的变径流化床中,研究不同粒径分布的硅粉流化特性,发现具有下锥体的流化床有利于宽筛分硅粉的流化。实验测量了不同表观气速条件下不同粒径分布硅粉流化床层的平均空隙率,对硅粉流化床的压力脉动进行功率谱分析发现,窄分布大颗粒硅粉具有典型的Geldart-B类颗粒的性质,而在宽筛分分布时却发现本应属于Geldart-B类颗粒却与30～80μm的硅粉的功率谱图相近,这说明加入细硅粉或宽筛分硅粉有利于改善流化质量。更多还原

【Abstract】 Silicon powder is an important raw material for direct synthesis of dimethyl-dichloro-silane in fluidized bed reactors. It has wide size distribution and non-spherical shape, and it is necessary to investigate the fluidization properties of silicon powders. A vitreous fluidized bed with a conic bottom section, diameter of 215 mm and a height of 1500 mm, has been built up for experiments. A powder backfill system with cyclone and hoppers is mounted in order to keep constant silicon quantity and size distribution in the fluidized bed. The bed voidage and entrainment for different silicon powders are measured experimentally. Moreover, pressure sensor is used to investigate the pressure fluctuation of the fluidized bed, and the power spectrum is analyzed using the FFT method. The measurements show that there is obvious main frequency at about 1.0 Hz for the power spectrum of silicon powders which belongs to Geldart-B class, but there is no obvious main frequency for 30-80 urn fine silicon powders and wide size distribution from 30 to 630 urn silicon powder. In this case, the power spectrum has a much wide distribution from 1.0 to 5.0 Hz. It means that a wide size distribution or introduction of fine powders can improve the fluidization quality of silicon powder effectively.更多还原