Effects of the mixer shape in a flow-type supercritical hydrothermal reactor as evaluated by neutron radiography and CeO₂ nanoparticle synthesis

The mixer shape in flow-type reactors plays a vital role when the reaction rate is much faster than the mixing rate. In this study, we performed neutron radiography measurements on a flow-type supercritical hydrothermal reactor to examine the water density profile of the mixer and to determine the mixing behavior of the supercritical water and reactant solution streams. We examined the mixing behavior of the conventional and proposed mixers under various flow conditions. We also performed supercritical hydrothermal CeO2 nanoparticle synthesis under the same mixing conditions and evaluated the effects of mixing behavior on the sizes of the produced CeO2 nanoparticles.