The mechanical and physical properties of agricultural bulk materials, such as wheat or corn, affect their behavior during transport and storage processes, e.g., in silos. The use of optical monitoring methods in such enclosed spaces is very difficult. Electrical capacitance tomography (ECT) is a non‐destructive and contactless method for measuring the inner space of the silo. It relies on changes in permittivity. With sensors evenly spaced around the circumference of the silo, it is a very effective technique to obtain real-time information about the behavior of the materials stored within.
David Zurovec and colleagues, Technical University of Ostrava, Czech Republic, used ECT to monitor the discharge of wheat and corn grains from a test silo with two differently sized openings. ECT measurements showed that, in general, both grains discharge in a similar way with respect to flow types. However, the influence of the different physical and mechanical properties was mainly reflected in different discharge times. If the orifice is too small in comparison to the material size, this leads to flow disturbances such as “bridging” (when grains form an arch over the opening). A bigger orifice eliminates the problem, resulting in a continuous flow.
The results demonstrate that the monitoring of discharge processes from a silo using ECT could be an innovative online monitoring method with a wide range of applications.
- Monitoring of the Discharge Process of Bulk Material in Silos Using Electrical Capacitance Tomography,
David Zurovec, Jakub Hlosta, Jiri Rozbroj, Jan Necas, Jiri Zegzulka,
Chem. Eng. Technol. 2018, 41, 1559–1565.
The article is part of a Focus Issue of Chemical Engineering & Technology.