2.2. Equipment
2.2.1. Fluidised bed equipment and process variables
A modified GEA Aeromatic-Fielder Strea-1 top-spray fluidised bed was used with a stainless steel fluidising chamber of 16 L. The air distribution plate consists of a perforated stainless steel plate (Ø 100 mm) with 78 holes (Ø 3 mm) covered with a metal grid with orifice diameters of 100 μm to avoid any particle loss when the bed is not fluidised. The physical dimensions of the fluidisation chamber may further be seen fromFig. 3. Modification to the original vessel design made it possible to insert a digital thermometer into the fluidisation chamber wall thereby making it possible to measure the bed temperature between the air distribution plate and the nozzle outlet. The location of this temperature probe was carefully chosen in order to make sure that no non-uniform temperature profiles due to wall- or spray-effects would interfere with the temperature measurements. In addition, an external humidity measurement apparatus (Testo 645 Thermohygrometer) was inserted above the nozzle allowing the relative humidity in the fluidisation chamber to be measured near the exhaust gas outlet.