Microwave vacuum drying of porous media:: Verification of a semi-empirical formulation of the total absorbed power

被引:11
作者
Péré, C [1 ]
Rodier, E [1 ]
Louisnard, O [1 ]
机构
[1] Ecole Mines Albi, Ctr Poudres & Proc, F-81000 Albi, France
关键词
electrostatic assumption; evaporation; experiments; dielectric properties; glass beads; pharmaceutical granules; vaporization;
D O I
10.1081/DRT-100104802
中图分类号
TQ [化学工业];
学科分类号
0817 ;
摘要
Vacuum drying,experiments were performed on a laboratory scale dryer with two porous materials: a packing of initially saturated glass beads and of unsaturated pharmaceutical granules. Several incident powers and two vacuum pressure levels were tested in order to demonstrate different drying mechanisms. The drying kinetics, temperature of the product and the absorbed power are presented and the coupling between the drying rate and the absorbed power is shown. A semi-empirical formulation of the total absorbed power is proposed taking into account the water content, the temperature and the dielectric properties of each phase. This formulation is based on a quasi-static assumption which allows the local electric field inside the material to be expressed with an analytical equation.
引用
收藏
页码:1005 / 1022
页数:18
相关论文
共 33 条
[1]  
ALTMEYER A, 1994, VAKUUM PRAXIS, V6, P117
[2]   DRYING CHARACTERISTICS OF THICK LUMBER IN A LABORATORY RADIOFREQUENCY VACUUM DRYER [J].
AVRAMIDIS, S ;
LIU, F .
DRYING TECHNOLOGY, 1994, 12 (08) :1963-1981
[3]   MICROWAVE-HEATING - AN EVALUATION OF POWER FORMULATIONS [J].
AYAPPA, KG ;
DAVIS, HT ;
CRAPISTE, G ;
DAVIS, EA ;
GORDON, J .
CHEMICAL ENGINEERING SCIENCE, 1991, 46 (04) :1005-1016
[4]   Highfrequency drying of porous material [J].
Bader, H ;
Schlunder, EU .
DRYING TECHNOLOGY, 1996, 14 (7-8) :1499-1523
[5]  
Baillon B, 1996, THESIS U PAU PAYS AD
[6]  
BAILLON B, 1996, P 10 INT DRYING S, VB, P1221
[7]  
BOUR S, 1998, P 11 INT DRYING S, VC, P2156
[8]   THE RELATIVE INFLUENCE OF DIELECTRIC AND OTHER DRYING TECHNIQUES ON THE PHYSICOMECHANICAL PROPERTIES OF A PHARMACEUTICAL TABLET EXCIPIENT .1. COMPACTION CHARACTERISTICS [J].
CHATRATH, M ;
STANIFORTH, JN .
DRYING TECHNOLOGY, 1990, 8 (05) :1089-1109
[9]  
CONSTANT T, 1992, THESIS I NATL POLYTE
[10]  
CONSTANT T, 1990, ACTE C SFT, V2, P245