FABRICATION AND EVALUATION THE PERFORMANCE OF A NOVEL PROTOTYPE COMBINED MACHINE FOR CHOPPING AND MILLING SOME AGRICULTURAL RESIDUES

A prototype combined machine was fabricatedfor chopping some agricultural residues, including rice straw (RS), corn stover (CS), mango tree pruning (MTP) and orange tree pruning (OTP).The experiments were carried out forthe RS and CS using the milling unit under drum speeds of 2000, 2500, 3000 and 3500 rpm corresponding to peripheral speeds of 10.47, 13.08, 15.7, and 18.32 m/sec, respectively, and concave clearances of 1, 2, and 3 cm. Moreover, MTP and OTP were chopped through operating the two units simultaneously using of different speeds of 1000, 1250, 1500, and 1750 rpm (corresponding to the same peripheral speeds mentioned above), for the cutting disc as a pre-chopping stage, then the chopping process was completed using the lower. The optimum machine productivity and machine efficiency were 0.6 Mg/h and 71.1% for milling RS and 0.8 Mg/h, 90 % for CS, respectively, at drum speed 3500 rpm and concave clearance 1 cm, which without was achieved the lowest energy consumption of 5.74 and 4.53 kW.h/Mg and criterion cost 37.6 and 29.7 EGP/Mg for RS and CS, respectively. The optimum machine productivity and machine efficiency of the two serial processes, chopping and milling were 1.28 Mg/h and 85.02% for MTP, 1.23 Mg/h and 81.68% for OTP at cutting disc speed of 1750 rpm (10.47 m/sec), milling drum speed 3500 rpm (18.32 m/sec), and concave clearance 1 cm which achieved the lowest energy consumption of 2.82 and 3.13 kW.h/Mg and criterion cost 18.79 and 19.84 EGP/Mg for MTP and OTP, respectively.