Catalytic pyrolysis of prickly pear cactus biomass for hydrogen-rich syngas production

Catalytic pyrolysis of prickly pear cactus ( Opuntia ficus-indica ) biomass was experimentally investigated as a route for producing hydrogen-rich syngas. A laboratory-scale fixed-bed reactor was used to evaluate the effects of temperature, zeolite addition, operating time, and feed particle size on product distribution and gas composition. Increasing the pyrolysis temperature from 500 to 650 °C progressively shifted the product distribution from condensable and solid fractions toward non-condensable gases. Under non-catalytic conditions, syngas yield increased from approximately 30 to 51 mass%, whereas zeolite-assisted pyrolysis increased the corresponding yield from approximately 44 to 61 mass%. The H 2 fraction in the syngas increased from about 18 to 31 vol.% without catalyst and from 26 to 39 vol.% with zeolite. Catalytic operation simultaneously reduced bio-oil and biochar formation, consistent with enhanced secondary vapor cracking, oxygen-removal reactions, reforming, and char–gas conversion. TG/DTG analysis showed earlier and more rapid thermal decomposition in the presence of zeolite. Thermal efficiency increased with operating temperature, reaching approximately 66% at 650 °C. Overall, zeolite-assisted pyrolysis redirected cactus-derived intermediates toward permanent-gas formation and enhanced hydrogen enrichment, demonstrating the technical potential of O. ficus-indica as a feedstock for hydrogen-rich syngas production while recognizing that drying demand, catalyst durability, gas conditioning, scale-up, and life-cycle performance require further assessment.