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ARS Home » Plains Area » Las Cruces, New Mexico » Cotton Ginning Research » Research » Publications at this Location » Publication #409640
Research Project: Improving the Production and Processing of Western and Long-Staple Cotton and Companion Crops to Enhance Quality, Value, and Sustainability

Location: Cotton Ginning Research

Title: Grinding and pelleting characteristics of municipal solid waste fractions

Author
item SMITH, ZACHARY - Idaho National Laboratory
item ISSAC, BLESSON - Idaho National Laboratory
item Tumuluru, Jaya Shankar
item YANCEY, NEAL - Idaho National Laboratory

Submitted to: Energies
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2023
Publication Date: 12/20/2023
Citation: Smith, Z., Issac, B., Tumuluru, J., Yancey, N. 2023. Grinding and pelleting characteristics of municipal solid waste fractions. Energies. 17(1):29. https://doi.org/10.3390/en17010029.
DOI: https://doi.org/10.3390/en17010029

Interpretive Summary: There is great interest in utilizing municipal solid waste for biofuel production. The major challenge of the MSW is low bulk density and high variable moisture content and particle sizes and shapes. This research tests novel preprocessing technologies such as dewatering, pelleting, and low-temperature drying. The MSW has various fractions and is separated manually into four different fractions (plastics, cardboard, thin and thick plastics). These fractions were analyzed for physical properties and chemical composition, such as proximate and ultimate composition, and the material was further processed to produce pellets using a flat die pellet mill. The pellet produced using cardboard and paper has met the ISO standard in density and durability. In contrast, the plastic pellets have a lower bulk density of <200 kg/m3 and durability of less than 90%, whereas paper and cardboard had higher bulk and durability values (>530kg/m3 and >90%).

Technical Abstract: The efficient utilization of low-cost carbon feedstocks, such as municipal solid waste (MSW), in biorefineries has become increasingly important for reducing GHG emissions and meeting the growing demand for renewable energy sources. However, MSW as a feedstock presents several challenges, including high moisture content, compositional variability, particle size and shape, density, and ash content. To address these challenges, the potential of mechanical dewatering and high-moisture pelleting processes for densifying MSW fractions, such as paper, cardboard, thin plastic, and thick plastic, into low-cost carbon feedstocks with improved handling and conversion properties were investigated. The effect of these preprocessing technologies on the critical quality attributes (CQAs) of the resulting pellets, including bulk density, durability, and size uniformity, were evaluated. The results showed that with these preprocessing technologies, the paper and cardboard fractions could be pelleted at moisture contents over 40% (w.b.) while achieving >99% durability and >300 kg/m3, while the high moisture plastic fractions were not suitable for pelleting. The thick plastic fraction processed in a screw press was shown to remove up to 30% of the moisture content in a single pass. These findings suggest that these mechanical preprocessing technologies can improve the physical properties of low-cost municipal solid waste fractions for biofuels production.