Evaluation of Co-Pelletization of Corn Stover and Plastic Waste as an Alternative Fuel Source for Cement Production

Corn stover and plastic waste, severely underutilized feedstocks generated in the U.S., could be co-pelletized to produce fuel for cement production. High-density polyethylene bags (0–25% in 5% increments, dry basis) and corn stover were co-pelletized using a flat ring pellet mill with die diameters of 6 and 8 mm. Physical and chemical properties were assessed to determine pellet quality. These results informed techno-economic and life cycle greenhouse gas emissions (GHGe) analyses for a Midwestern plant producing 400,000 metric tons of pellets annually. The system boundary included feedstock acquisition at the pellet plant, size reduction, co-pelletization, and transportation of the pellets to the cement plant by rail. Total resource requirements in terms of raw materials, labor, fuel, equipment, the facility, and utilities were estimated. It was determined that the pellets would be delivered to the cement plant at USD 112.4–138.6/t pellets. The life cycle analysis estimated a total GHGe of 1621.1–1753.1 kg CO2e/t pellets associated with the pellet production, transportation, and combustion. The results suggest that substituting 25% of the thermal energy requirement of a cement plant with a 1.1 million t clinker annual production capacity with plastic–stover pellets would reduce the GHGe by 2.8% compared to 100% of the total energy requirement supplied by coal.