Effect of different shapes of hummer mill blades and moisture content on mechanical and physical properties of grinded alfalfa hay and pelleting under different temperature and particle sizes

Abstract

The work conducted at the field laboratories in Grdarasha affiliated to the college of agricultural engineering sciences / Salahaddin University in Erbil, Kurdistan region, Iraq. Two studies were conducted, the first study laid out by a 2×2 factorial experiments based on Complete Randomized Design (CRD) to examine the effect of Two Factors & its interactions, the first factor was hammer mill blade types, dull blade (B₁) and sharpened blade (B2) while the second factor included two levels of alfalfa hay moisture content (M1=16 and M2=20) % on the particle size distribution and hammer mills power consumption. The second study laid out by a 2×2×2 factorial experiments based on Complete Randomized Design (CRD) for studying the effect of the three factors included different particle size (P₁=4 and P₂=8) mm, moisture content (M₁=16 and M₂=20) % and temperature (T1=65 and T2=75) ℃ and its interaction on the manufactured pellets durability index (PDI) directly after cooling and after storing in a room temperature conditions, pellets unit density also measured. The results showed that increasing moisture content led to an increase in the geometric mean length, also the interaction between the dull blade and moisture content (B₂M₂) increased and it was 5.44mm, also higher moisture content decreased in power consumption, the lowest power consumption during alfalfa hay grinding was 1.84 Kw recorded with the same treatment. The highest PDI value directly after cooling was recorded with the interaction of P₂M₁T₁ which was 85.65%. Pellets durability index (PDI) increased after storing for all treatments, the bigger particle sizes significantly effected on PDI after storing, the highest value recorded for the interaction treatment (P₂M₂T₂) and reached 93.58%. The highest pellets unit density value was 1009.71 Kgm^-3 obtained with the interaction of P₁M₁T₁

Keywords

• alfalfa pellets
• hammer blades
• particle size
• pellets durability
• unit density