Optimization of key operating parameters to enhance performance and energy efficiency of a hammer mill for corn grinding

This study was conducted at the Faculty of Agriculture, Damascus University, to investigate the effect of sieve hole diameter, number of hammers, and concave clearance on the efficiency of a locally manufactured hammer mill. Three levels of sieve hole diameters (D3: 3 mm, D4: 4 mm, and D5: 5 mm), three levels of hammer numbers (N24: 24, N26: 26, and N28: 28 hammers), and two levels of concave clearance (C5: 5 mm and C10: 10 mm) were evaluated. Their impact on ground corn productivity, energy consumption, machine efficiency, and compression ratio was assessed. Results were analyzed using Exstate 2014 software, and differences between treatment means were tested using the Least Significant Difference (LSD) test at a significance level of 0.05, with three replications. The results showed that increasing sieve hole diameter from D3 to D5 and reducing concave clearance from C10 to C5 significantly enhanced productivity (an increase of 52.13% for D5 compared to D3) and machine efficiency. Conversely, energy consumption decreased. Moreover, reducing sieve hole diameter and increasing the number of hammers led to a higher compression ratio and increased energy consumption. The optimal parameters for grinding corn using the tested hammer mill were a sieve hole diameter of D5 (5 mm), a concave clearance of C5 (5 mm), and N26 (26 hammers). This combination resulted in 938.5 kg/h productivity, acceptable energy consumption of 2948 W, and machine efficiency of 96%. Additionally, the optimal compression ratio (38%) was achieved when using a sieve hole diameter of D3 (3 mm), concave clearance of C5 (5 mm), and N28 (28 hammers).