Experimental research on breakage characteristics of feed pellets under different loading methods

Abstract Particle breakage is a common phenomenon during the processing of production, storage, and transportation. Because of the requirements for pellet integrity in poultry farming, research on the breakage characteristics of feed pellets is necessary. In this paper, repeated compression tests under different loading forces and repeated impact tests under different air pressures were carried out with feed pellets as the research object. The breakage behaviors were described, and the particle size distribution of feed pellets was analyzed quantitatively. The variation of energy and pulverization rate under different loading methods was analyzed with the increase of loading cycles. The relationship between energy and pulverization rate was fitted. The results showed that the breakage degree decreased gradually from top to bottom in repeated compression tests, and the crack density positively correlated with the loading force. The size of the feed pellets during repeated impacts decreased continuously and was negatively correlated with air pressure. The Weibull function could fit the particle size distribution well, and the R2 values were greater than 0.97 and 0.96. Weibull parameters showed a steady breakage degree in compression tests and a growing breakage degree in impact tests. The energy and pulverization rate increased with the loading cycles in different loading methods. The model of Vogel and Peukert could describe the relationship between energy and pulverization rate well, and the R2 values were greater than 0.94. The minimum energy required for pellet breakage in compression was greater than that in impact due to the compaction of the feed particle bed under repeated compression. The results can provide basic theory and data support for breakage characteristics and quality evaluation of feed pellets.