Ultrapyrolysis of n-hexadecane in a novel micro-reactor

A novel reaction system, which provides better control compared with the tubular flow reactors of previous researchers, was employed to study the ultrapyrolysis kinetics of n-hexadecane, a gas oil model compound. Ultrapyrolysis, or ultra rapid pyrolysis, refers to thermal cracking under conditions of high temperature, very short reaction time, high heating rate and rapid product quench. Modern-day ‘millisecond’ furnaces, operating under such conditions, have demonstrated significantly higher ethylene yields due to improved selectivity. The automated micro-reaction system employed a Curie point pyrolyser to rapidly heat microgram n-hexadecane samples to high temperature. The Curie point phenomenon ensured that a reproducible and well-defined temperature was attained. A rapid direct quench system was used to stop the reactions and transfer the products to the analyser. n-Hexadecane was pyrolysed at 576–842 °C for 100–3200 ms. Peak ethylene production (28 wt%) was exhibited at ultrapyrolytic conditions of 842 °C and 500 ms. A first-order kinetic analysis performed on the pyrolysis data yielded an activation energy of 39.4 kcal mol−1.

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