Prediction of Effective Diffusion Coefficient in Rotating Disc Columns and Application in Design

A rotating disc column (RDC) with inner diameter 68 mm and 28 compartments is used in this study. Parameters including Sauter mean diameter, hold-up and mass transfer coefficient are measured experimentally un-der different operating conditions. The correlations in literature for molecular diffusion and enhancement factor equation including eddy diffusion, circulation and oscillation of drops are evaluated. A new equation for the effec-tive diffusion coefficient as a function of Reynolds number is proposed. The calculated values of mass transfer co-efficient and column height from the previous equations and present equation are compared with the experimental data. The results from the present equation are in very good agreement with the experimental results, which may be used in designing RDC columns.

缅甸民主化,中国怕不怕?

近来,中国的国际问题专家在美国常被问起:"缅甸民主化,中国怕不怕?"仔细想来,这个问题背后实际上隐含着另外两个互相关联的问题。一是"中国害怕民主化吗?"作为共产党执政的中国,历来倡导人民民主是社会主义的生命,发展社会主义民主政治是中国共产党始终不渝的奋斗目标。中国非但不害怕民主化,反而大力提倡和发展民主。然而,在美国人看来,"民主化"指的是,从其他政权形态转变成民主体制的过程。