Unlocking the potential of corn husk through pyrolysis and gasification: Characterization, kinetics, and agglomeration analysis

Abstract

Cornhusk (CH) is an agricultural residue produced in large quantities globally and discarded as solid waste. Thermochemical conversions, such as gasification and pyrolysis, can valorize CH into fuel and other value-added products. This study examined the viability of the thermochemical conversion of CH by studying its physicochemical characteristics, chemical kinetics, and ash agglomeration behavior. The gross composition, elemental composition, and heating value revealed the energy potential of CH. The values H/C and O/C values of CH (0.20 and 1.15) indicate the possibility of a favorable hydrogen yield. TGA data at degradation rates of 5, 10, 15, and 20 $°C{\min }^{-1}$ were used to derive kinetic and thermodynamic parameters using isoconversional methods. The Ozawa-Flynn-Wall (FWO), Kissinger-Akahira-Sunose (KAS), and Starink techniques yield activation energies of 178.03–232.80, 177.45–234.81, and 177.71–235.02 kJ mol⁻¹, respectively. Thermodynamic studies revealed the energy requirements, spontaneity, and reaction progression. The master plot method revealed that CH followed a fourth-order reaction model. The low activation energy of CH makes it suitable for thermochemical processes. Based on the oxide compositions, the alkali index, bed agglomeration index, and acid-to-base ratio were estimated as 0.719, 0.074, and 2.04, respectively. These indices indicate the occurrence of agglomeration, necessitating the implementation of appropriate abatement methods to ensure seamless gasification of corn husk, especially in fluidized beds.