Design and Performance Evaluation of an Automated Continuous Mixing–Pelletizing Machine for Animal Feed and Organic Fertilizer Production

Abstract

                This study aimed to design and develop an automated continuous mixing–pelletizing machine for the commercial production of animal feed and organic fertilizer, and to evaluate its performance and optimal operating conditions. The effects of raw material moisture content at 12%, 15%, and 18% (wet basis) and feeding rates of 120, 160, and 200 kg/h on pellet quality, production capacity, and energy consumption were investigated. The developed prototype consisted of four main subsystems: a raw material hopper system, a mixing system, a conveying and holding system, and a pelletizing system, which operated continuously under an automated control system.

                The experimental results showed that the prototype achieved average production capacities of 181 kg/h for pelleted animal feed and 168 kg/h for pelleted organic fertilizer. The mixing performance was satisfactory of 15% resulted in the highest pellet durability for both animal feed and organic fertilizer. In addition, a feeding rate of 160 kg/h provided the most suitable balance between production rate, operational stability, and energy consumption.

                An engineering economic analysis indicated that the annual fixed cost of the machine was approximately 69,900 THB. The break-even production quantities were 22,843 kg/year for animal feed pellets and 25,985 kg/year for organic fertilizer pellets. These values correspond to approximately 124 and 160 operating hours per year, or about 0.8–1 month of actual operation assuming an average working time of 8 hours per day. The results demonstrate that the developed continuous mixing–pelletizing machine has strong potential for efficient production of animal feed and organic fertilizer at community or commercial scales.