Kinetics of catalytic and non-catalytic pyrolysis of Nerium Oleander

Nerium Oleander is a plant that is not consumed by both human and cattle. The pyrolysis of leaves and stems of Nerium oleander was performed using thermogravimetric analysis without and with Zeolite 5A catalyst from room temperature to 1000 degrees C, with different heating rates from 5 degrees C min(-1) to 20 degrees C min(-1) under nitrogen atmosphere, with a biomass to catalyst ratio of 4:1 for all studies involving catalyst. Three different particle sizes namely, 1000, 500, and 125-mu m were chosen for the study. Three degradation stages, referred to hemicellulose, cellulose and lignin were observed under pyrolysis conditions, based on the degradation temperature. The mass loss rate curve was deconvoluted using Fraser-Suzuki function to obtain mass loss rate for individual constituents of biomass. The activation energy for each constituent was determined using Friedmann isoconversional model, as recommended by ICTAC, from deconvoluted data. The reaction model f(alpha), was determined using the generalized master plots method. The pre-exponential factor was obtained from the fundamental mass loss rate relationship with f(alpha). The reaction order for hemicellulose degradation was found to be 3rd order, RandomScission model for cellulose degradation, and nucleation model (Avrami Erofeev 1.5 order) for lignin degradation both for non-catalytic and catalytic pyrolysis. The activation energy for catalytic pyrolysis was found to be 30-40 kJ mol(-1) lower for hemicellulose and cellulose, and 200 kJ mol(-1) lower for lignin compared to noncatalytic pyrolysis. The amount of coke deposited during catalytic and non-catalytic pyrolysis is also compared.