Effects of operating temperature on the bubble phase properties in fluidized beds of FCC particles

• We analyze the bubbling regime of FCC catalyst, fluidized at 100, 400, 700 °C.
• We acquire data by bed collapse tests and images of erupting bubbles.
• Results are collected at varying fluidization velocity and bed aspect ratio.
• We recognize a better quality of bubbling regime at high temperature.
• A large number of smaller bubbles travel across a more permeable particulate phase.

Some important characteristics of the bubbling regime, relevant to a sample of FCC catalyst with an average size of 110 μm belonging to group A of Geldart's classification, were investigated at 100, 400 and 700 °C. Non-invasive optical techniques were employed for acquiring data of bed collapse tests as well as images of bubble eruption at the free surface of the bed. The experiments, performed at varying fluidization velocity and bed aspect ratio, show that a smoother regime of bubbling is observed at superambient temperature, where thermal enhancement of interparticle forces leads to higher porosity and lower interstitial flow in the emulsion phase while smaller bubbles are observed to flow across the bed at higher frequencies.

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