Thermogravimetric analysis of pyrolysis of Delonix regia biomass in the presence of zeolite, mixed metal oxides and carbon supported noble metal catalysts

Abstract

Renewable energy from biomass waste shall become an effective alternative to faster-depleting fossil fuels and pyrolysis is a suitable approach to produce renewable energy from biomass. Further, kinetics parameters are essential in designing reactors for pyrolysis and this work provides kinetics of catalytic pyrolysis (CP) of Delonix regia (DR) biomass. In addition to this significance, the novelty of this work includes the utilization of catalysts of three different kinds such as zeolite (Na–Y), mixed metal oxides (TiO2+ZnO), and supported noble metal (Pt/C) catalysts at varying loads of 30–10 wt %. All experiments were performed in a micro pyrolyzer (thermogravimetry analyzer) under non-isothermal conditions at five heating rates (5, 10, 20, 35, and 55 °C min−1) in a temperature range of 25–1000 °C. To estimate kinetic factors (KF) and thermodynamic parameters (TP), five iso-conversional techniques such as Differential Friedman (DFM), Kissinger–Akahira–Sunose (KAS), Ozawa–Flynn–Wall (OFW), Starink (STK), and Distributed Activation Energy (DAE) were employed. KAS technique yielded the lowest mean activation energy, Eα (181.29 kJ mol−1), and frequency factor, ko (2.10 E+16 s−1) factors by use of Na–Y zeolite of load 10 wt % whereas the corresponding change in enthalpy is 177 kJ mol−1, change in Gibbs free energy is 178 kJ mol−1, and change in entropy is −9.58 E−04 kJ mol−1 K−1. Criado's master plots confirmed the reaction pathway as: second order (F2), power-law (P4), contraction area (R2), zero order (F0), contraction volume (R3), and fourth order (F4) for 20 °C min−1 from DFM technique for CP of DR by using Na–Y zeolite catalyst of load 10 wt %.

Keywords

• Delonix regia
• Catalytic pyrolysis
• TGA
• Na–Y Zeolite
• TiO2+ZnO
• Pt/C