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Transshipment of compacted soybean is characterized by labor-intensive processes, long operating times, and a great amount of dust that cannot be collected by sealed devices. This dust significantly reduces air quality of the workshop and represents a great threat to human health. Solving this problem has been a great challenge in the soybean storage industry. For this reason, in the present study the concept of a transshipment system for soybean clearance was proposed. This system can simultaneously achieve real-time transshipment of falling materials and air curtain control of fugitive dust. The main factors influencing the performance of the air curtain dust control system were investigated using numerical simulation, and the effects of the exhaust-to-pressure ratio K and air curtain outlet velocity V on dust control efficiency were determined. Results showed that the width of the dust-collecting paths increased with increasing K and V values. We also found out that dust-escape paths were mainly concentrated in the transition height between the complete air curtains and local air curtains. At the beginning of the process, dust control efficiency rapidly increased and the increment rate became slower as K increased. When K = 1.5 and V = 5–6 m/s, dust control efficiency reached values up to 94.03–97.73%. Based on numerical simulation results, the prototype transshipment system for soybean clearance was developed, and the effectiveness of air curtain dust control was validated via smoke tracing experiments. After the application of the developed system, occupational lung disease can be significantly reduced, and transshipment efficiency per clearance can be enhanced by approximately 67% (about 50,113￥ can be saved in terms of energy consumption and labor resources). An extra granary can be saved after using the newly developed system for 36.5–52.1 clearances.

Air entrained during the transfer of bulk materials from one belt conveyor to another is a primary factor of dust emissions. However, theoretical calculation of the volumetric flow rate of air entrainment is very difficult to obtain, resulting in inaccurate and unreliable design and operation of dust control systems. This paper summarizes existing theoretical calculation and experimental methods, as well as techniques employed to decrease air entrainment. The current study focuses on the process of physical motion and energy conversion of falling bulk materials, the flow pattern of free-falling particles, and the factors which influence the generation of air entrainment. Additionally, the impact of certain devices on the weakening or guiding of air entrainment is also discussed. Finally, the authors propose several future research options to further investigate air entrainment.