Natural zeolite catalyst for tar removal in biomass gasification Systems: Kinetics and effectiveness evaluation

Abstract

This research aims to study abundant Jordanian zeolite in its natural form as a catalyst to eliminate tar, modelled by toluene, from gasification systems. Natural zeolite was characterized using TGA, BET, XRF, SEM and particle size analysis. The pseudo first-order kinetic parameters of thermal cracking and catalytic conversion reactions of toluene were determined at temperatures of 700 °C, 800 °C and 900 °C. It was found that thermal cracking, carbonization, and dry reforming reactions took place simultaneously. Natural zeolite achieved a greater degree of toluene conversion than that achieved with the thermal cracking, with the highest value of 79 % at 900 °C. The activation energy of the catalytic conversion of toluene reaction was found to be 62.1 kJ/mol while that of thermal cracking of toluene to be 85.0 kJ/mol. The presence of the catalyst lowered the activation energy. The thermal cracking test had a frequency factor of 1.5432 × 104 s−1, while the test employing Jordanian zeolite to catalyze the conversion of toluene had a frequency factor of 3.1754 × 103 s−1. Natural Jordanian zeolite proved to be a suitable catalyst that can be used in tar reforming processes in gasification systems, especially at 800 °C.