Intracrystalline Diffusion in Molecular Sieve Zeolites by the Tracer-Pulse Method

扩散系数是吸附设计的重要参数 分离系统、气体净化和催化转化 流程. 多孔沸石系统通常用于进行本发明的方法。 运输过程。 扩散系数的测量 分子筛沸石导致了大量的，无法解释的 吸附技术测定值之间的差异 和核磁共振（NMR）方法。 可能的 对这些差异的解释是（1）未能考虑到 热效应，（2）未能考虑质量传递 阻力，（3）未能解释表面屏障 晶体表面的电阻，（4）晶体中的差异 吸附剂的结构，和（5）在吸附剂中的差异， 吸附剂的再生。 现在有了独一无二的 同时测量扩散系数的可能性， 三种独立的方法。 分析 结果将产生显着的见解的困境， 在文献中报道了很大的差异，这项研究可能 为传质过程提供改进的设计能力 涉及微孔介质中的气体扩散。

Diffusivity is an important property for the design of adsorption separation systems, gas purification, and catalytic conversion processes. Porous zeolite systems are often used to perform the transport processes. The measurement of diffusivities in molecular sieve zeolites has resulted in large, unexplained differences between values determined by adsorption techniques and the nuclear magnetic resonance (NMR) method. The possible explanations for these differences are (1) failure to account for thermal effects, (2) failure to account for mass transfer resistance, (3) failure to account for a surface barrier resistance at the crystal surface, (4) differences in the crystal structure of the adsorbent, and (5) differences in the regeneration of the adsorbent. There is now the unique possibility of simultaneously measuring the diffusivities in identical systems by three independent methods. Analysis of the results will yield significant insights into the dilemma of the large differences reported in the literature, and this study may provide improved design capabilities for mass transfer processes involving gas diffusion in microporous media.