Study of the parameters affecting the separation of foreign matters from lentils by gravity table separator and optimization of sifting device

bagheri, Hadi and Rasekh, Mansour and Kianmehr, Mohammad Hossien and Kouravand bard pareh, Shahriar (2016) Study of the parameters affecting the separation of foreign matters from lentils by gravity table separator and optimization of sifting device. Doctoral thesis, university of Mohaghegh Ardabili.

Text (مطالعه پارامترهای موثر بر جداسازی مواد خارجی از عدس توسط دستگاه جداکننده میز ثقلی و بهینه سازی دستگاه بوجاری) Hadi bagheri.pdf Download (385kB)

Abstract

In this study, a gravity separator and optimized sifting device were used for separation of foreign materials from lentil seeds. The gravity separator has five adjustable parameteres such as longitudinal and latitudinal slopes, oscillation frequency and amplitude and velocity of air, and then their influence on maximum separation of foreign matters from lentil seeds were evaluated. Using of dimensional analysis and a model study that is common in fluid mechanics, some dimensionless number (v/aω) were produced that were effective in reduction of numbers of parameters. Sifting device of optimized has three adjustable air velocity, longitudinal slope and oscillation frequency, the impact of these parameters to achieve the maximum separation of foreign materials in mass lentils, were studied. Also, in this study, some physical and aerodynamic properties of lentil seed were evaluated as a function of grain moisture content in the range of 9.2-18.2% (w.b). These properties which included average of length, width, thickness, arithmetic mean diameter, geometric mean diameter, surface area, sphericity, 1000 seed mass, angle of repose, bulk density, true density and terminal velocity, were measured, also in this study some physical properties and aerodynamic lentils mass impurities were measured and evaluated as well. The physical properties and aerodynamic including mass of 1000 seeds, true and bulk densities, porosity, terminal velocity and angle of repose were measured. The static coefficient of friction of mass lentils were determined on various surfaces of the glass, galvanized sheet, black iron sheet, plywood, particle board were measured. Results of the gravity separator showed that increased latitudinal slope of the table from 0.5° to 1° and longitudinal slope of table from 1° to 2°, led to increase separation percentage of impurities in bulk lentils, also the results showed that at settings of longitudinal slope of 2°, latitudinal slope 1°, and frequency of oscillation 400 cycles.min-1, air velocity 5.7 ms-1 and amplitude of oscillation 5 mm (v/aω=171), the separation percentage has maximum value. In this case, the output lentil seeds contained the least amount of foreign materials here. The results of fitting of data fit software showed that reduce the dimensionless number v/aω=180 to v/aω=171, increased separated percentage of impurities with the lentils bulk, but decrease in the dimensionless number v/aω=171 to v/aω=152, the decreased separation percentage of foreign materials from lentils. Results of separation percentage of foreign materials from lentils showed that the best artificial neural network topology perdiction for the artificial neural network Linear Tanh Axon. Results of optimized sifting device showed that decreased longitudinal slope of sieves from 22° to 18°, decreased air velocity from 6.4 m s-1 to 4.2 m s-1 and decreased the frequency of oscillation of sieves from 412 cycle min-1 to 290 cycle min-1, increased separation percentage of foreign materials from lentils and also, the results demonstrated that at longitudinal slope of sieves at 18°, 4.2 ms-1 air velocity, and 290 cycles.min-1 frequency of oscillation, the maximum separation foreign materials from lentils was 49.1%.

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