CAREER: Structure/ Property Relationship of Adherent SiC Coated Fe-Ni-Cr Alloys in Ethylene Pyrolysis Environments

Suny At Stony Brook, Stony Brook NY

Investigators

Abstract

The demand for ethylene, one of the highest production chemical commodities in the world will exceed 100 million metric tons by 2010 as products derived from ethylene are displacing conventional materials in packaging, building, automotive and other applications. High temperature pyrolysis of hydrocarbons has been practiced for over a half century and still over a half billion dollars of Fe-Ni-Cr based tubular products are consumed each year. The culprit, catalytic coke formation, leads to increased tube wall temperature, poor heat transfer, increased pressure drop, inner tube diameter reduction, and tube plugging. The combination of in- service operation and decoking cycles has reduced tube life by 4-6 years. This Faculty Early Career Development (CAREER) award will concentrate on improving process efficiency by (1) limiting catalytic coke formation by applying adherent SiC coatings via pulsed laser deposition to the inner diameter of tube material traditionally used for ethylene pyrolysis service, (2) determining what microstructural changes the SiC coated Fe-Ni-Cr tubing undergoes during service, and (3) determining what influence changes in microstructure have on the life of the tubing. Since diffusion underlies the self- healing mechanism of coatings as well as the mechanism of coating degradation by interdiffusion with the substrate, knowledge of the diffusion characteristics of the system is of fundamental importance. The program will also establish a foundation for a lifetime of educational excellence through improved pedagogy, curriculum development, outreach, and mentoring. This effort is highlighted by the ASM endorsed Northeast Teachers' Training Camp beginning in 2004 under the PIs direction.