Abstract
A concept of successive contact mechanism has been introduced to account for the influence of dilute phase catalyst on overall conversion of reaction in fluid beds. A theory has been given, as a simpler version of the proposed model, for an isothermal and irreversible first order reaction. To test the concept, axial distribution of bed density has been measured for small scale fluid beds. Rather freely suspended catalyst particles are observed in the dilute phase in enough amount to contribute to the progress of reaction. The theory has revealed for the progress of reaction that the catalyst particles located in the bubble phase are interchangeable with those suspended in the dilute phase and vice versa.
