Thermodynamic parameter for steam reforming reaction of biodiesel by-product using nano-sized perovskite catalysts

Abstract

The catalytic steam reforming of biodiesel by-product (glycerol) GSR for hydrogen production was carried out using perovskite nano-catalysts (LaNiO₃ and LaCoO₃).The two catalysts were prepared by the reverse microemulsion method and characterized by XRD, by TG/DTA, BET and HRTEM. Equilibrium product compositions of GSR reaction were determined at different reaction temperature (400-700^oC) with glycerol: water molar ratio 1: 10 in a fixed-bed flow system under atmospheric pressure. The equilibrium constant and thermodynamics parameters (ΔG, ΔH and ΔS) were calculated. The results revealed that, the conversion of the glycerol gradually increases with reaction temperature until reached 100% at temperature 700^oC. LaNiO₃ show higher gas product than LaCoO₃ at the same reaction temperature. Moreover, H₂ yield increased from 0.11 to 3.15 for LaNiO₃ and 0.01 to 1.33 for LaCoO_3. On the other hand, LaCoO₃ provided more deactivation resistant along to 16h than LaNiO₃. XRD analysis of spent catalysts revealed the presence of La₂O₂CO₃ phase. On using LaNiO₃, the produced product at 700^oC was found to have a moderate calorific value (284.706 Btu/ft³) as compared to highcalorific value on using LaCoO₃ (434.785 Btu/ft³) at 600^oC due to the low yield of CO₂ (15 mol %).