Local modeling of mass transfer with chemical reactions in a gas-solid fluidized bed. Application to the chemical vapor deposition of silicon from silanes

For several years, new processes have been emerging in the field of gas sol id fluidization, involving complex gaseous chemical reactions, more often a t high temperatures. As an illustration of these new technologies, the part icular case of silicon CVD (Chemical Vapor Deposition) from silanes will be described. Traditional models of fluidized beds are intrinsically unable t o represent such complex operations. Hence, as a first attempt, a new model has been developed to locally calculate mass transfer inside and around an isolated bubble rising through the fluidized bed. Examples of results in t he case of CVD are presented. They confirm the applicability of the approac h, which however needs further improvements. (C) 1999 Elsevier Science S.A. All rights reserved.