Residence time distribution measurements and flow modeling in a supercritical water oxidation reactor: Application of transfer function concept

Residence time distribution (RTD) measurements are carried out in a flow-through tubular supercritical water oxidation (SCWO) reactor using ex situ pulse response experiments. The experiments are performed from ambient to supercritical water conditions with a volumetric flow rate fixed at 1 ml/min. The transfer function concept is used to interpret tracer information and to elucidate hydrodynamic flow patterns inside the “hot zone” of the reactor vessel. The experimental RTD curves are modeled by an axially dispersed plug flow. At supercritical conditions, the studied tubular SCWO reactor can be characterized as a mixed flow system (with Péclet numbers of 1.4–2). The results also indicate the presence of fast preferential fluid flow in the reactor below 573 K and 10 MPa.