MATHEMATICAL MODELLING OF A ROTARY SWIRL CYCLONE SCRUBBER

A Rotary Swirl Cyclone Scrubber (RSCS) is a device designed to remove SO₂ and ash from the combustion products of an entrained-flow gasifier. It uses a combination of highly swirling flow and water sprays to produce high heat and mass transfer rates. In order to develop a better understanding of the operation of this device, modelling has been performed using an extended version of CFX-F3D. Simulations have been performed to examine the flowfield in the device and to determine SO₂ and ash capture efficiencies. The simulations show that the water jets used to remove the SO₂ from the gas completely change the direction or swirl in the device, resulting in a highly turbulent flow. The experimental SO₂ capture efficiency and the outlet temperature are well reproduced using a water droplet size of 60 μm, with this value being determined via fitting to a particular experiment. Predictions of ash particle capture are found to be in good agreement with the experimental data.