Sustainable Pneumatic Transport Systems of Cereals

Abstract

Technological pneumatic transport installations are designed to move materials from one place to another in various phases of the production process. For example: loadingunloading materials (cereals) using rail and marine transport, air tunnel container transport, supplying combustion installations with burning coal dust. The main parameter in pneumatic transport installations is the velocity of air. For the regime of motion with material particles in suspension, for a given flow material, the higher the velocity is the greater the pressure loss will be and thus the energy consumption for transportation will increase. In horizontal pipes at the beginning of motion flow we have a compact regime, and then due to decrease air velocity a continuous layer regime is forming. This is the apparent motion in wich the pressure losses increase with the decrease of velocity. By reducing the air velocity the thickness of the deposited material increases and the real air passage section decreases and therefore the real air velocity increases, which explains the increase in pressure loss. In vertical pipes if the air velocity decreases below the lower limit of volant transport, after a critical area of instability, a transportation fluidized bed is established, the pressure losses being much larger than the particles in suspension mode. If the velocity further decreases the particles can not be entrained in the air.