Thermochemical cycling of Ca(OH)2-based granules: real-time visualisation and analysis

Kurzfassung

A reactor device was specially developed to study the changes in the structural integrity and mechanical stability of the coated granules. The setup emulates the conditions of a directly-heated moving bed reactor and at the same time allows for the real-time visualisation of the reacting granules. It consists of a capped-bottom pipe that can hold 0,3 L Ca(OH)2 granules which is coupled with a glass flange located on top. The heat and reaction gas are supplied from the bottom and the temperatures are measured by three thermocouples located at different heights in the. A high-resolution camera equipped with a macro lens takes images of the granules placed inside the reactor device at different times during each experiment. On the material side, three batches of granulated Ca(OH)2 were tested in a 20-fold cycle experiment series: uncoated granules, granules coated with Al2O3 and Ca(OH)2/CaCO3 composites. The images taken were processed and analysed to assess the structural integrity whereas the samples were subject of sieve analysis, thermal analysis and compression tests.