Synergistic co-pyrolysis of corn stover and refuse-derived fuel with microplastics: Kinetic and thermodynamic study

Abstract

Biomass and refuse-derived fuel are prevalent constituents of municipal solid waste worldwide, exerting persistent pressures on environmental ecosystems. Consequently, there arises a critical necessity for their effective recycling and management. This study investigates the co-pyrolysis of corn stover (CS) and Refuse-Derived Fuel (RDF) in a 1:1 mass ratio through kinetic and thermodynamic analyses. Using a thermogravimetric analyzer and differential scanning calorimetry (DSC), the co-pyrolysis process is examined within a temperature range of 25–900 °C, under varying heating rates of 5, 10, and 20 °C/min in a nitrogen atmosphere. Kinetic analysis is conducted employing model-free methods, including Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), Starink, and Tang, with subsequent estimation of thermodynamic parameters such as enthalpy change (ΔH), entropy change (ΔS), and Gibbs free energy (ΔG). Additionally, mass and energy balances specific to the blended feedstock are calculated to evaluate future operational efficiency. The investigation reveals the higher heating values (HHV) of CS and RDF as 17.879 and 20.035 kJ/kg, respectively. Notably, the DTG and DSC curves indicate a positive interaction between CS and RDF's plastic component at temperatures exceeding 400 °C. Kinetic analysis yields average activation energies for CS, RDF, and the CS-RDF blend (1:1) as 202.26, 235.87, and 212.60 kJ/mol, respectively, suggesting a reduction in activation energy for the blend. In summary, these findings offer valuable insights into the co-pyrolysis of CS and RDF, thereby contributing to the optimization of co-pyrolysis as an effective waste-to-energy conversion process.

HIGHLIGHTS

• Comprehensive study of the co-pyrolysis of corn stover and RDF.

• Kinetic and thermodynamic analysis for co-pyrolysis of a mixture of corn stover and RDF.

• There was an apparent synergistic effect from the co-pyrolysis.

• The HHV was used in predicting the energy balance within the co-pyrolysis system.

Keywords:

• Co-pyrolysis
• corn stover
• RDF
• kinetic analysis
• thermodynamic analysis

Acknowledgement

The authors gratefully acknowledge the financial support from Wayne and Gayle Laufer Foundation. We also appreciate the support from Idaho national laboratory (INL) for providing the corn stover pellet and refuse-derived fuel (RDF) pellet feedstocks.

Disclosure statement

No potential conflict of interest was reported by the author(s).