Production of solar CO via two-step neodymium oxide based thermochemical CO2 splitting cycle

Abstract

Detailed thermodynamic scrutiny of the solar thermochemical neodymium oxide-based CO2 splitting (Nd-CS) cycle is reported. The thermal reduction (TR) and CO2 splitting (CS) reaction temperatures required for the operation of the Nd-CS cycle were determined. The equilibrium compositions of Nd2O3, NdO, and O2 exhibit that the initiation of the TR of Nd2O3 is feasible at 1982 K, and the complete conversion is possible at 2232 K. As per the delta G analysis, the CS reaction was feasible at all temperatures above 300 K. After understanding the chemical thermodynamic equilibrium of the Nd-CS cycle, the efficiency analysis was performed by using the HSC Chemistry 9.9 software. The results obtained via the efficiency analysis shows that the Nd-CS cycle was capable of attaining the highest possible ηsolar-to-fuel-Nd-CS = 9.45% at partial TR of Nd2O3 = 55% (TH = 2154 K). Application of HR = 20%, 40%, 60%, 80%, and 100%, improved ηsolar-to-fuel-Nd-CS at TR-Nd = 55% (TH = 2154 K) up to 10.51%, 11.84%, 13.55%, 15.85%, and 19.09%, respectively.