Offline   1.440.666.6786  1.404.537.2266

Build My System

Notes

INTRODUCTION TO THE DESCRIPTIVE EQUATIONS FOR CHEMICAL REACTORS

There are 3 fundamental ideal types of reactors. Laboratory reactors are almost exclusively related to these ideal forms.  Larger reactors,  pilot-plant or commercial scale,  can be mathematically described usually by deviations from these ideal reactors. Additional complications to the descriptive or "design" equations are introduced by the presence of multiple phases.

METAL CRYSTALLITE SIZE DETERMINATION: COMPARISON OF CHEMICAL AND PHYSICAL METHODS

Recent Altamira Notes have discussed the use of several different chemisorption techniques to determine crystallite sizes for supported metal catalysts.These techniques, temperature-programmed desorption, static chemisorption, and pulse chemisorption, can all be described as "chemical" methods because they rely on some way of monitoring the chemisorption or desorption of molecules on metal surfaces. A second general approach to the determination of metal crystallite sizes involves the use of techniques which may be described as "physical" methods. The objective of this Note is to compare the chemical methods described in earlier Notes to several physical methods discussed below.

PULSE CHEMISORPTION

Previous issues of Altamira Notes have discussed different selective chemisorption techniques and how they may be used to determine the specific metal surface area of supported metal catalysts.   One additional technique commonly used for the same purpose is pulse chemisorption. This method is one of the simplest, most straightforward ways to measure adsorbate uptake by a metal surface; however, as with most other measurements in catalysis, interpretation of the results can be problematic if the nature of the catalyst system and the experiment itself are not well-understood. This Altamira Note discusses the principles of pulse chemisorption experiments as well as some common experimental observations