Chemical vapor deposition and homogeneous nucleation in fluidized bed reactors: silicon from silane

Two models are developed to treat the simultaneous chemical vapor deposition (CVD) on solid particles and gas-phase nucleation of solid fines in a fluidized bed reactor. The first assumes both gas and solids to be well mixed. The second distinguishes between the grid, bubble and emulsion region of the bed. The population balance is used to describe the size distribution of fines, and the growth of large particles is ascribed to CVD and capture of fines. The results of the two models are compared to the experimental data from the JPL six-inch fluidized bed reactor. Good agreement between predictions and experimental data is established for the production rate, gas conversion and quantity of fines formed. The suppression of fines is most efficient when a CSTR flow pattern is approached in the bed.