Standpipe flow modeling, experimental validation and design recommendations

In the Fluid Catalytic Cracking process (FCC), the role of the standpipe is to transfer solids from a low pressure vessel to a high-pressure vessel, Aeration along the length of the standpipe is necessary to keep the solids fluidized and prevent irregular flow or low pressure buildup. It the aeration flowrate is too high, wall bubbles hinder solids flow. A model was developed to predict the vertical spacing between aeration taps and validated with experimental data. A preliminary model estimates the aeration flowrate which will keep the solids fluidized without large wall jets. Recommendations for design and startup procedures are proposed. (C) 2002 Elsevier Science B.V. All rights reserved.