Microwave drying of wet clay with intermittent heating

Vorhauer N, Tretau A, Bück A, Prat M (2019)

Publication Type: Journal article

Publication year: 2019

Journal

Drying Technology Taylor & Francis

Book Volume: 37

Pages Range: 664-678

Journal Issue: 5

DOI: 10.1080/07373937.2018.1547740

Abstract

In this article, we study an alternative process for the conservative drying of wet clay based on combined microwave heating and convective drying. The study is founded on an experimental analysis of the processes that control drying of porous matter in presence of temperature gradients. We show and discuss that process control cannot be reliably based on temperature alone because mass transfer phenomena associated with microwave heating dictate drying kinetics. Essentially, the occurrence of pressure build up and liquid expulsion, dominating mass transfer if microwave heating is uncontrolled or with high power, vitally depend on the moisture content of the clay. As a consequence, the deterioration of clay is problematic if internal evaporation rates are high, thus at the start of drying when also the moisture content is high. Following this, we propose intermittent microwave heating in combination with convective drying periods with the aim to reduce overall drying time (compared to conventional convective drying) and to improve product quality by reduced material shrinkage. Drying experiments indicate that the overall drying time reduction and product quality depend on the frequency and duration of the two subsequent periods of intermittent heating and convective drying. The observations can be explained with the evolution of the pore-scale distribution of liquid and vapor during drying.

Authors with CRIS profile

Andreas Bück Professur für Partikeltechnik

Involved external institutions

Otto-von-Guericke-Universität Magdeburg DE Germany (DE) Brick and Tile Research Institute DE Germany (DE) Université Fédérale de Toulouse Midi-Pyrénées FR France (FR)

How to cite

APA:

Vorhauer, N., Tretau, A., Bück, A., & Prat, M. (2019). Microwave drying of wet clay with intermittent heating. Drying Technology, 37(5), 664-678. https://doi.org/10.1080/07373937.2018.1547740

MLA:

Vorhauer, N., et al. "Microwave drying of wet clay with intermittent heating." Drying Technology 37.5 (2019): 664-678.

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