In this paper, particle settling in supercritical CO2 (SC-CO2) was studied to obtain a terminal velocity calculation for engineering applications. A visualization apparatus and high-speed camera system were used to record the settling process. Fourteen sets of experiments involving various pressures (7.37-13.50 MPa), temperatures (31.5-41.0 degrees C), particle diameters (0.212-0.85 mm) and particle densities (2630 and 3120 kg/m(3)) were conducted. The terminal velocity in SC-CO2 was found to be similar to that for liquid CO2 because of the similarity of the forces acting on the particles. A power-law relationship between the particle's Reynolds and Archimedes numbers was redefined based on a dimensional analysis. Using the power-law relationship to fit the experimental results, an explicit terminal velocity formula that considers the viscosity of SC-CO2 was obtained. This formula could describe the settling rate of particles in SC-CO2 within the Reynolds number range from 1000 to 5000. (C) 2015 Elsevier B.V. All rights reserved.