Ahmad Azari

The aim of this work is to investigate the combustion mechanism of catalytic coke formed in the olefin plants furnaces as a chemical reaction fouling. The objectives are removing the steam injec-tion and modeling a dry oxidation process based upon Thermogravimetry (TG) and Temperature-Programmed Oxidation-Gas Chromatography (TOP-GC) experiments. Comprehensive data were obtained for 5.0-15.0 % vol. oxygen content in the combustion atmosphere while the tempe-rature was tuned from 600 to more than 1000°C. The concentrations of carbon monoxide and carbon dioxide were determined as TPO criteria for reaction rate and kinetic parameters along with the mass loss in TG tests. The results revealed the optimum decoking temperature in order to decrease the decoking run-time, improve energy conservation and enhance the cleaning effi-ciency. DTG thermogram revealed the temperatures that the combustion rate of catalytic coke increased gradually. TPO-GC experiments approved the optimal decoking temperature in accor-dance with the plant’s operation manual. The propounded dry decoking mechanism depicted the combustion reaction of carbon and CO2 follows by O2 chemisorption at carbon surface, obtaining the activation energy, converting to the activated complex and production of CO2.