Combination of drying and separation of composite agricultural products for energy saving

In drying of heterogeneous vegetable material as some aromatic and medical herbs, the desired moisture content (MC) is achieved, which is an average of the moisture content of the different parts, but if each one is analyzed, it is found that to come to this average, one of these has a less MC, and the other a higher MC than the desired, which have consequences in physic and chemical properties of the material and in the energy inputs to the process. This process, represents unnecessary expenditure of energy in the excess drying of one tissue, at the time that some parts are left at higher MC than the desired, which also means fewer incomes and less quality in the operation. The main objective of this research is develop dryer equipment that allows differential drying and the separation of different plant tissues of products, so as to save energy in the process.

For this it should be made an integration of the drying models to predict the drying behavior of differential drying and identify the point in which the separation can be made; develop a device for the separation of plant tissue, design, build and test a prototype of a separating dryer machine. So far the developed activities and accomplishments are:

- Study of the dynamics of drying of a mixture of clover and ryegrass: through literature review and development of experiments in the laboratory of drying, the main parameters of drying behavior of the materials of the mixture under different conditions was settled. These parameters are essential for the design of the final equipment and the development of required models of drying.

- Study of the mechanical behavior of the mixture components: through the adaptation of some laboratory equipment, the material characteristics that describe its behavior during the drying and separation processes were established. Among these are forces of separation, aerodynamic behavior and sleep dynamic angles, among others.

- Study of drying under rotary motion: A rotating equipment for testing of Rotary drying, with the variation of different parameters of the drying speed, air temperature and composition of the mixture was designed and built. The tests allowed to obtain all the required parameters for the design of the final prototype and to better understand the phenomenon of dried herbs in a rotary dryer.

- Design of a prototype of dryer and separation: Once established the parameters of drying and separation a dryer which allows the separation of the components of the mixture using a sieve inside of the device was designed. For its correct sizing, tests of the dynamics of the mixture separation were performed.

- Development of models: in each of the activities above described, have been developed mathematical models that describe the behavior of materials under drying, rotary motion, separation and sieving. - Articles: two articles have been written, of which one has already been approved for publication in the magazine "drying technology" while the other was delivered for evaluation.

responsible : Dr. Fernando Lozano Osorno

Doctoral Thesis, 14-Okt-2015:

Simultaneous Drying and Separation of Composite Agricultural Material for Hay Processing