Microwave-assisted drying of clay roof tiles

Abstract

Following the successful drying experiments conducted with a domestic microwave oven, this study presents the results of laboratory scale drying of clay tiles. The drying process was realized as a combination of convective drying with microwave heating. In detail, the dependence of drying time and total energy consumption on process conditions were investigated. For this analysis, the microwave power was either intermittently supplied or continuously increased with a ramp profile during the microwave heating periods. Additionally, the impact of the drying air temperature was investigated. The scale-up from the basic experiments to the lab scale plant was realized by successive increase of the sample size. Process control was based on temperature measurement of the drying sample. The results suggest intermittent microwave heating as an alternative option for fast and sound drying of clay roof tiles. Increase of air temperature instead had a minor impact on drying indices. In comparison with continuous heating, the major advantages of intermittent heat supply are its energy efficiency and the better options for process control.

Keywords:

• Microwave irradiation
• roof tiles
• wet clay
• scale-up
• intermittent heating
• convective drying

Acknowledgements

The authors thank Peter Püschner from Püschner GmbH + Co KG for the technical support with the microwave dryer.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

The research project was carried out in the framework of the industrial collective research program (IGF no. 209 19 BG/2). It was supported by the Federal Ministry for Economic Affairs and Energy (BMWi) through the AIF (German Federation of Industrial Research Associations eV) based on a decision taken by the German Bundestag.