CONFIRMATION OF HEAVY-COMPONENT ROLLUP IN DIFFUSION-LIMITED FIXED-BED ADSORPTION

The objective of this work is to present breakthrough concentration profiles for the binary adsorption of oxygen (weak) and nitrogen (strong) on 4A zeolite molecular sieve. Of particular interest is the experimental confirmation of the strong component breakthrough behavior as predicted by A. Kapoor and R.T. Yang. Based on experimental data, it is found that the breakthrough of oxygen and nitrogen occurs nearly simultaneously. In addition to the significant equilibrium-related rollup of the lighter (weaker adsorptive) oxygen component, there is a small, but readily discernible, diffusion-related nitrogen peak as well. This nitrogen peak was found to occur before the much larger oxygen rollup peak. The equilibrium model, which assumes no resistance to mass transfer, exhibits a relatively wide separation between the arrival of the two fronts and a single rollup for the weaker adsorptive. Since this model does not recognize differences in micropore diffusion rates, no heavy (strong) component rollup is predicted.