Enhanced Al₂O₃ Interlayer Coating for Inhibition of Filamentous Coke Formation in n-Dodecane Cracking Reaction

Abstract

To manage heat generated during the supersonic flight of aircraft, hydrocarbon cracking reactions were proposed. To suppress cracking reactions occurring within stainless steel walls of fuel flow, an alumina coating was applied. By optimizing the pretreatment of stainless steel and the number of alumina coating cycles, an optimal method for alumina coating was identified. Alumina coating under optimal conditions exhibited minimal weight loss, even under ultrasonic vibration. Furthermore, it was found that the coated alumina exhibited a heat absorption reaction, resulting in 887 Btu/lb with suppression of surface catalytic reactions and a predominance of pure thermal cracking reactions. The change in heat absorption over time could be suppressed from 16 to 2.3%, and the coke formed on the wall was decreased by over 35% from 98 to 63.3 mg. Moreover, it was observed that incorporating the HZSM5 catalyst within the alumina layer not only maintained wall durability but also enhanced heat absorption by over 15% compared to thermal cracking.