Experimental

Fluidization at Process Conditions

Experimental work focuses on advancing the understanding of the mechanisms dominating the fluidization behaviour of industrial catalysts at process conditions and the investigation of the relative importance between the hydro-dynamic and interparticle forces. In particular, the effect of high temperature, presence of additives on the particles’ surface, effect of increasing the fines content and fines size distribution on fluidization are investigated.

A small industrial scale High Temperature Fluidized bed Rig has been developed to test powders at ambient pressure and at temperatures up to 800°C. The Rig is made in Inconel, 140mm diameter x 1000mm height, it has a wall thickness of 3mm and is fitted with a very fine (i.e. pore size of 20micron) stainless steel sintered distributor plate to ensure a high pressure drop and therefore a good and even fluidization in the bed. The upper disengaging section is fitted with a removable stainless steel filter to reduce the loss of any elutriated fine material. Two solenoid valves are fitted on the rig to cut the gas supply to the bed and to vent the gas trapped in the windbox section, in order to perform the bed collapse test. See Photograph under X-ray Imaging.

Effect of Interparticle Forces on High Temperature Fluidization  of an E-cat FCC

Fluid-bed Rheology

An innovative approach has been developed to link fluidization experiments with rheological studies in order to investigate the relative importance between the hydrodynamic and interparticle forces on the fluidization behaviour of gas fluidized beds and to determine the apparent viscosity of fluidized powders.

A mechanically stirred fluidized bed rheometer (msFBR) has been developed to measure the flow properties of powders at minimum fluidization by means of an agitating system. Torque measurements are obtained at different rate of aeration and impeller depth. A model based on the failure properties of the materials has been developed to predict the torque and to determine the stress distribution in the msFBR for any given rate of aeration.

A coaxial cylinders rheometer, Couette type, has been developed to study the rheology of fluidized and expanded powders. This instrument allows the use of a model for non Newtonian fluids to determine the apparent viscosity of fluidized beds.

mechanically stirred Fluid-bed Rheometer (msFBR)

Couette Fluid-bed Rheometer

Thermogravimetric Analysis - Pyrolysis of waste materials

Thermogravimetric analysis is conducted using a TGA/DSC to investigate the thermal degradation behaviour and heat flow for a number of polymers, co-polymers, powders and other materials. The analysis shows the potential of conducting pyrolysis or gasification in order to upgrade certain elements of waste into useful products and/or valuable petrochemicals. Collaboration with the industry (Ravago Plastic, Belgium) has been established on TGA assessments.

Pyroclastic Flows

Through interdisciplinary collaboration with the Laboratoire Magmas et Volcanos of the University Blaise Pascal in Clermont-Ferrand in France the Group is studying the fluid-mechanics of pyroclastic flows generated during explosive volcanic eruptions. Volcanic materials are fluidized at high temperature and X-rays are used to explain the ability of pyroclastic flows to maintain high gas pore pressure, and hence low friction, during run-out.

(Created 20 November 2007, last updated 20 February 2009)