(153e) Blending in Above Ground Storage Tanks with Side Entering Agitators: Effect of Scale and D/T

The blending of fluids in large, above-ground storage tanks is widely practiced in the petroleum industry yet little research exists of this mixing operation. The most demanding case exists when liquids have stratified into light and heavy layers. The time it takes for the density of the fluid to become axially homogeneous is defined as the blend time. Brine and water have been used as simulants for the light and heavy phase, notably in Wesselingh’s work using conductivity to determine the blend times (Wesselingh 1975). Although Wesselingh only explored one propeller geometry, several important geometrical properties were explored, including ratio of propeller vessel diameter and liquid depth to vessel diameter. This study is a continuation of recent studies (Giacomelli et al. 2014) (Grenville et al. 2018) (Boyer et al. 2018) wherein Wesselingh’s conductivity technique is applied, but expounds on the geometric impacts including impeller diameter, tank diameter (scale), total liquid height, brine height. Notably, the mixing vessel diameters are varied between 4’, 6’, 12’ to capture scale effect. Blend time predictions are traced to distinct regimes; the regimes are best distinguished using Richardson number, 𝑅𝑖= 𝑔Δ𝜌𝜈_𝐻/𝐷𝜌𝜀 . The implications for scale up and geometric alterations on blend time are discussed.