DEVELOPMENT OF A FIELD-GOING UNIT TO SEPARATE FIBER FROM HEMP (CANNABIS SATIVA) STALK

Abstract

The hemp (cannabis sativa) plant has large biomass yield and a high percentage of cellulose and lignin, which makes hemp one of the most challenging crops to process for fiber. A prototype field-going unit for separating fiber from stalk was developed based on a forage harvester and a straw walker from a grain combine. The forage harvester’s cutterhead was modified to achieve the cutting, beating, and scutching functions desired for fiber separations. The straw walker was used to achieve the shaking and screening functions desired for fiber cleaning. The prototype was tested in field conditions with the following treatments: two field retting times, two cutterhead configurations, two straw walker speeds, and two feeding rates. Assessments of the performance of the prototype were made on the perspectives of fiber yield, fiber purity, fiber loss, and fiber length distributions. The fiber yield from the prototype represented 41% to 61% of the initial fiber content of the raw hemp stalk. The purity of the output fiber ranged from 35% to 52%. The most effective treatment combination was longer retting time, lower feeding rate with a cutterhead configuration having both scutching bars and knives.