Migrating Temperature 'Thermo-Chromatographic' Pulses (TCP) in Different Zeolites and Other Microporous Materials

摘要

The so-called thermo-chromatographic pulse (TCP) is a dynamic selective dielectric heating phenomenon which has been studied in a variety of microporous materials, namely different faujasite-type, A-type or ZSM-5-type zeolites but also in γ-Al_2O_3 and silica gel. It could be shown that the strength of this specific heating effect in a radio-frequency field is strongly influenced by the characteristic interaction of water with the tested materials which depends, in addition to the microstructure, on the hydrophobicity represented by the Si/Al ratio. With the help of interaction models for the microscopic scale, these different heating behaviors could be explained. For zeolites NaY and 3A, the dependencies on experimental parameters such as radio-wave power input, injected amount of water or gas flow rate were investigated in more detail. In particular, the maximum temperature in the TCP and its speed in the packed bed were studied.