Aerodynamic Separation and Fractional Drying of Alfalfa Leaves and Stems—A Review and New Concept

Abstract This article examines the state-of-the art on aerodynamic separation and drying of leaves and stems. Relevant aerodynamic and drying characteristics of alfalfa leaves and stems, important in the design and functional performance evaluation of appropriate drying and separation systems, are presented. General features and design parameters of rotary drum dryers are discussed. A new efficient approach to combined drying and separation in a rotary drum dryer is described in which fresh or pre-wilted alfalfa mixture is dried at a moderate temperature, and in the same operation the dry leaf fraction is aerodynamically separated from the stem fraction. Preliminary test data obtained from the dryer indicated that the separated product stream had comparatively high leaf purity, confirming the feasibility of the new approach.

[1]  Greg Schoenau,et al.  Methods of Expediting Drying Rates of Chopped Alfalfa , 1993 .

[2]  R. M. Ford,et al.  Thermal Diffusivity of Alfalfa Stems , 1969 .

[3]  S. Gan-Mor,et al.  Separation of leaves from stems with a perforated rotating drum under suction , 1986 .

[4]  W. K. Bilanski,et al.  Separation of Alfalfa Silage Into Stem and Leaf Fractions in a Horizontal Airstream , 1989 .

[5]  Shufen Jiang,et al.  Thermal Properties of Haylage , 1986 .

[6]  W. K. Bilanski,et al.  Aerodynamic Properties of Alfalfa Particles , 1968 .

[7]  W. K. Bilanski,et al.  HIGH-TEMPERATURE DRYING OF ALFALFA STEMS , 1965 .

[8]  Shahab Sokhansanj,et al.  DESIGN, EXPERIMENTAL AND ECONOMIC EVALUATION OF A COMMERCIAL-TYPE SOLAR DRYER FOR PRODUCTION OF HIGH-QUALITY HAY , 1998 .

[9]  John B. Solie,et al.  Selected Physical Characteristics and Aerodynamic Properties of Cheat Seed for Separation from Wheat , 2000 .

[10]  J. R. O'Callaghan,et al.  The effect of temperature on the drying rate of grass , 1971 .

[11]  Shahab Sokhansanj,et al.  Experimental Evaluation, Simulation and Optimization of a Commercial Heated-Air Batch Hay Drier: Part 1, Drier Functional Performance, Product Quality, and Economic Analysis of Drying , 1996 .

[12]  C. W. Hall.  HANDBOOK OF INDUSTRIAL DRYING , 1988 .

[13]  W. K. Bilanski,et al.  Thermal Properties of High Moisture Content Alfalfa , 1992 .

[14]  Greg Schoenau,et al.  Simulation of natural and solar-heated air hay drying systems. , 1993 .

[15]  R. M. Halyk,et al.  HIGH-TEMPERATURE DRYING OF ALFALFA LEAVES , 1965 .

[16]  John Kelly,et al.  FLIGHT DESIGN I N ROTARY DRYERS , 1992 .

[17]  Frederick A. Kamke,et al.  Computer simulation of a rotary dryer. Part I: Retention time , 1986 .

[18]  Shahab Sokhansanj,et al.  Experimental Evaluation, Simulation and Optimization of a Commercial Heated-Air Batch Hay Drier: Part 2, Computer Simulation and Optimization of Hay Drier Performance , 1996 .

[19]  Shahab Sokhansanj,et al.  HEAT TREATMENT OF CHOPPED ALFALFA IN ROTARY DRUM DRYERS , 1990 .

[20]  J. Frame,et al.  Temperate Forage Legumes , 1997 .

[21]  J. R. O'Callaghan,et al.  Digital simulation of agricultural drier performance , 1971 .

[22]  Shahab Sokhansanj,et al.  Kinetics of Dehydration of Green Alfalfa , 1996 .