Performance characteristics of small scale biomass pelletizing equipment
Authors: Rooney, D, D Ciolkosz, V Puri, M Gearhart, B Gray
Description: The operational characteristics of a small scale biomass pelletizer were studied in an attempt to assess the impact of feedstock and process variables on pellet quality and tendency of plugging. Ground switchgrass (6mm screen) was used as the primary feedstock for tests on a horizontal rotating plate die" pelletizer with 6mm die openings. Variations in moisture content, particle size, admixture material, and operating procedure were tested. Pellet quality and tendency of plugging were measured using a subjective scale, and power demand by the device was monitored. Results indicate that unmodified ground switchgrass does not readily or repeatably densify into pellets. Poor pellet quality and/or die plugging were common - which indicates the difficulty of establishing appropriate rheological conditions when the properties of the ground switchgrass are coupled with the operating characteristics of the pelletizer. Feedstock variations, including addition of fines, incorporation of oil, and addition of moisture, did not yield repeatable improvements in performance. However, the addition of both starch and moisture did result in a repeatably high quality pellet. Maintaining tight contact between die and roller was found to be an important operational characteristic, as was the preheating of the die and the batch loading of the in-feed hopper. Feeding all the biomass into the hopper at once allowed the die to clog enough so that it allowed proper time and pressure for the pellets to form."""
Keywords: performance characteristics of small scale biomass pelletizing equipment
Technical field: technical_fields_app1
Session name: Biological systems