Development and Performance Evaluation of Bio Chopper for Agricultural Biomass Processing

Agricultural biomass residues such as rice straw, weeds, fodder grass, and vegetable residues are generated in huge quantities every year and improper disposal of these materials causes serious environmental pollution and management problems. Efficient biomass size reduction technologies are essential for improving composting, mulching, livestock feeding, and biomass utilization processes. Therefore, the present study was conducted to design, fabricate, and evaluate a low-cost bio chopper for efficient chopping and size reduction of agricultural biomass materials. The machine was developed at the Workshop Machinery and Maintenance (WMM) Division of Bangladesh Rice Research Institute (BRRI), Gazipur, Bangladesh. The developed bio chopper mainly consisted of a conical feeding hopper, chopping chamber, rotating blade assembly, electric motor, shaft and bearing system, speed regulator, and supporting frame. The machine operated based on impact and shearing action generated by high-speed rotating blades inside the chopping chamber. Performance evaluation of the developed machine was conducted under laboratory conditions using rice straw, weeds, fodder grass, and vegetable residues. The performance parameters included chopping capacity, chopping efficiency, particle size reduction, uncut material percentage, power consumption, and specific energy consumption. The chopping capacity of the machine ranged from 145.2 to 178.5 kg/h, while chopping efficiency varied from 91.4% to 95.1% depending on biomass type and moisture content. The highest chopping capacity and chopping efficiency were observed for fodder grass due to its softer texture and lower cutting resistance. The percentage of uncut biomass materials ranged from 4.9% to 8.6%, whereas average particle size varied from 19.4 mm to 24.5 mm. Power consumption of the machine ranged from 420 W to 445 W and specific energy consumption varied from 2.49 to 2.89 Wh/kg. The developed bio chopper showed satisfactory chopping performance, stable operation, and efficient energy utilization for agricultural biomass processing applications.