Modelling highly skewed chromatographic response curves

✍ Scribed by D. Gelbin; H.-J. Wolff; S. Friedrich

• Book ID: 102693057
• Publisher: American Institute of Chemical Engineers
• Year: 1982
• Tongue: English
• Weight: 625 KB
• Volume: 28
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690280202

✦ Synopsis

Abstract

A model is presented in which damaged pores are distributed throughout a network of undamaged pores within a spherical particle. The differential equations are solved according to the numerical procedure of Haynes, Jr. (1975). The model is intended to simulate more highly skewed chromatographic response curves than the two‐zone model recently proposed by Chou and Hegedus (1978).

Pulse chromatographic measurements in fresh NaMgA zeolites using i‐butane as a tracer which only enters the macropores yield response curves with relatively low skew, which are readily fitted by a system of equations accounting for diffusion in a monodisperse pore system. For hydrothermally treated zeolites effective diffusivities and Henry constants are considerably lower and the skew higher than in fresh samples.

Curve fitting with the model proposed below is quite satisfactory, and the characteristic parameters determined are approximately constant at the flowrates studied. Application of the model should not be restricted to hydrothermally treated zeolites, but may be extended to catalysts or adsorbents with macroporous structures damaged by other forms of ageing.