Fiber Yield and Energy Requirement of Hemp Decortication Using a Hammermill

Abstract

<abstract><title><italic>Abstract. </italic></title> Hemp fiber provides industries with numerous possibilities for bio-product market development. An experiment was conducted to decorticate green and retted hemps using a hammermill. Treatments included three screening scenarios (19.3 and 25.7 mm round-holed screens and no screen), three feeding masses (75, 125, and 200 g), and two precutting scenarios (hemp cut into 40 mm segments and non-cut hemp). Fiber yield, core (or hurd) yield, effectiveness of decortication, and power and energy requirements were experimentally determined. Results showed that effects of precutting and feeding mass significantly interacted with screen scenarios. With screens, precutting green hemp resulted in reduced energy requirement for decortication, while without screens, non-cut and cut green hemp required comparable energy. A higher energy requirement was observed only for the 25.7 mm screen for the retted hemp. For both the green and retted hemps, mixed results were obtained for the effects of feeding mass on the power requirement. However, clear trends were observed for the effects of feeding mass on the energy with larger feeding mass requiring greater energy. Fiber yield varied from 1.0% to 34.6%, and core yield varied from 11.8% to 73.7%, depending on the treatments. In most cases, better fiber and core yields, and greater decortication effectiveness were observed for the cut hemp with smaller feeding mass and the presence of a screen when compared to the non-cut hemp with higher feeding mass without screens.