Effect of Season and Moisture Content on the Efficiency of Energy Consumption During Grinding and Physical Parameters of Barley Grind

Physical properties of grinds such as modulus of uniformity, modulus of fineness, particle size, number of particles and surface area per gram of ground samples were determined. Throughputs and power requirements for barley using different hammer mill screen sizes were determined in a size reduction process. Ampere and volt meters were installed in the power supply circuit to monitor electric current and voltage. Dimensions of the ground product were determined by use of the standard Taylor sieves being shaken by a Ro-Tap machine. Barley grains at three moisture contents in three seasons (summer, rainy and winter) were ground using a hammer mill with five different screen sizes (2, 3, 4, 5 and 6 mm). The grain bulk density varied from 453.0 to 500 kg/m³ as the grain moisture decreased from 11.87 to 8.33%. The energy requirements for grinding barley grain decreased from 3.886 kWh/q to 0.216 kWh/q as the screen size increased from 2 mm to 6 mm. The energy consumption was lower (P<0.05) in summer season compared to winter season. The energy consumption was 289, 82, 75 and 102% more as the screen size decreased from 3 to 2, 4 to 3, 5 to 4 and 6 to 5 mm, respectively. The throughput decreased from 533.8 kg/h to 267.6 kg/h as the moisture content increased from 8.33 to 11.87%. Per thousand grain mass increased linearly from 36.38±1.32 to 38.64±1.42g (P<0.05) as the moisture content increased from 8.33 to 11.87%. With increase in moisture level, the number of coarse particles and modulus of fineness increased significantly (P<0.05). The surface area (cm²/g) decreased (P<0.05) linearly from 56.56 to 27.50 with the increase in screen size from 2 to 6 mm. The modulus of uniformity ranged from 1: 7: 2 to 9: 1: 0 in winter season, 0: 7:3 to 8: 2: 0 in summer season and 0: 8: 2 to 8: 2: 0 in rainy season as the screen size increased from 2 to 6 mm. The modulus of fineness was in the range of 3.05 to 4.93, 3.18 to 4.65 and 4.18 to 5.73 during winter, summer and rainy season, respectively.