[en] Power consumption in the oil mixing process is very much affected by the impeller design. Minor modification on the impeller design might result in better mixing and less energy consumption. This paper reports an early stage of applying the observation technique to modify three standard impellers, namely the Pitched blade turbine impeller, the CHEMSHEAR impeller and the Vertical Flat-Blade Turbine Impeller. The advantages and disadvantages of these three impellers were analyzed; accordingly minor modification on the impeller design is adopted. The CFD tool is used to evaluate one of the modified impellers; results indicated that the modified impeller achieves better fluid dispersion.