Analysis of energy requirement for hemp fibre decortication using a hammer mill

Abstract

Hemp fibre decortication is an important procedure in hemp fibre processing. The cost of energy during decortication has a direct impact on the commercial value of hemp fibres for industrial products. This study investigated the specific energy requirement for hemp decortication using a hammer mill and the length size distribution of output fibre. Three screen opening sizes (19.28 mm, 25.74 mm, and no-screen scenario) and three feeding masses (200 g, 125 g, and 75 g) were used in hammer mill decortication tests. Test results showed that the 200 g feeding mass and the small screen opening size required the highest specific energy (73.84 J/g). Screen opening size affected the fibre length distribution. For all three feeding mass scenarios, more short fibres were produced when a smaller screen opening was used. Based on the results of analysis using existing Kick's, Rittinger's, and Bond's laws, a linear model was developed to fit the test data in regard to relating specific energy with initial and final fibre lengths. The model performed well for specific energy estimations, especially for the case under 200 g feeding mass.