Thin-layer modelling of the convective, microwave, microwave-convective and microwave-vacuum drying of lactose powder

Lactose-water samples were dried under selected convective, microwave, microwave-convective and microwave-vacuum conditions in an experimental system (2.45 GHz, 90 W). Irrespective of the drying technique, a typical drying profile, with a constant drying rate stage followed by two falling rate periods, was exhibited. The magnitude of the drying rate, however, was dependent on the convective air temperature and velocity, and system pressure. The experimental moisture loss data were fitted to selected semi-theoretical and empirical thin-layer drying equations. The mathematical models were compared according to three statistical parameters, i.e. reduced chi-square, root mean square error and residual sum of squares. The drying characteristics were satisfactorily described by the Page, Logarithmic, Chavez-Mendez et al. and Midilli et al. models, with the latter providing the best representation of the experimental data.

[1]  W. K. Lewis.  The Rate of Drying of Solid Materials. , 1921 .

[2]  M. Parti,et al.  A THEORETICAL MODEL FOR THIN-LAYER GRAIN DRYING , 1990 .

[3]  A. Midilli,et al.  A NEW MODEL FOR SINGLE-LAYER DRYING , 2002 .

[4]  I. Dincer.  Moisture Loss from Wood Products During Drying—Part II: Surface Moisture Content Distributions , 1998 .

[5]  S. M. Hendorson.  Grain Drying Theory (I) Temperature Effect on Drying Coefficient , 1961 .

[6]  M. Parti,et al.  Selection of Mathematical Models for Drying Grain in Thin-Layers , 1993 .

[7]  G. D. Saravacos,et al.  Microwave/vacuum drying of model fruit gels , 1999 .

[8]  H. S. Ramaswamy,et al.  Microwave-assisted convective air drying of thin layer carrots , 1995 .

[9]  Jasna Prlić Kardum,et al.  COMPARISON OF CONVECTIVE, VACUUM, AND MICROWAVE DRYING CHLORPROPAMIDE , 2001 .

[10]  Da-Wen Sun,et al.  Selection of EMC/ERH Isotherm Equations for Rapeseed , 1998 .

[11]  Juming Tang,et al.  TEMPERATURE AND MOISTURE CHANGES DURING MICROWAVE DRYING OF SLICED FOOD , 1999 .

[12]  W. Mcminn,et al.  Microwave Drying of Multi-component Powder Systems , 2003 .

[13]  W. Mcminn,et al.  Microwave-Vacuum Drying of Pharmaceutical Powders , 2003 .

[14]  M. García-Alvarado,et al.  Modeling of Drying Curves for Some Foodstuffs Using a Kinetic Equation of High Order , 1995 .

[15]  Y. Onur Devres,et al.  The thin layer drying characteristics of hazelnuts during roasting , 1999 .

[16]  D. R. Pangavhane,et al.  Drying behaviour of brined onion slices , 1999 .

[17]  Yahya I. Sharaf-Eldeen,et al.  A Model for Ear Corn Drying , 1980 .

[18]  Can Ertekin,et al.  Drying of eggplant and selection of a suitable thin layer drying model , 2004 .

[19]  Dursun Pehlivan,et al.  Modelling of drying kinetics of single apricot , 2003 .

[20]  M. Abdelghani-Idrissi.  Experimental investigations of occupied volume effect on the microwave heating and drying kinetics of cement powder in a mono-mode cavity , 2001 .

[21]  C. Kiranoudis,et al.  MICROWAVE VACUUM DRYING KINETICS OF SOME FRUITS , 1997 .

[22]  Arun S. Mujumdar,et al.  Advances in drying , 1980 .

[23]  W. Mcminn,et al.  Microwave–convective drying characteristics of pharmaceutical powders , 2005 .

[24]  Osman Yaldýz,et al.  THIN LAYER SOLAR DRYING OF SOME VEGETABLES , 2001 .

[25]  V. Karathanos.  Determination of water content of dried fruits by drying kinetics , 1999 .

[26]  P. Panchariya,et al.  Thin-layer modelling of black tea drying process , 2002 .

[27]  G. E. Page,et al.  FACTORS INFLUENCING THE MAXIMUM RATES OF AIR DRYING SHELLED CORN IN THIN LAYERS. , 1949 .

[28]  Ray A. Bucklin,et al.  Effects of Drying Air Parameters on Rice Drying Models , 1985 .