Enhancing granular mixing performance in static mixer with wedge-block blending elements

Abstract

The static mixer captures immense attention as an efficient, energy-saving and low-cost device for mixing grain particles, which plays a critical role in improving food nutrition, tastes and cooking styles. This study pursues better performance of static mixer, and adopted the discrete element method to establish a particle-blanking mixing model for mung beans and brown rice. A self-designed wedge-block continuous collision static mixer was compared with the Kenics and the Low Pressure Drop (LPD) static mixers, and a bench test was carried out to evaluate the particle mixing of the three mixers. The results manifest that, in terms of mixing efficiency, the average flow rates of Kenics, LPD and wedge-block static mixers were 0.33 kg/s, 0.22 kg/s and 0.43 kg/s in the simulation, compared to 0.35 kg/s, 0.27 kg/s and 0.51 kg/s in the bench test, respectively. As for mixing uniformity, the relative standard deviation (RSD) values for Kenics, LPD and wedge-block static mixers were 24.95 %, 21.87 % and 7.44 % in the simulation, and 30.34 %, 35.93 % and 9.64 % in the bench test, respectively. In summary, the proposed wedge-block static mixer, able to boost the mixing rate and quality, is an ideal choice for the continuous production of pellet mixing, thanks to its superior mixing performance than Kenics and LPD in mixing mung bean and brown rice. These findings lay an essential basis for optimizing granular static mixer in the future.