Carbon formation on stainless steel 304H in convection section of ethane cracking plant

Abstract

The coking of stainless steel 304H alloy (SS304H) has been investigated in ethane-steam mixtures in the presence/absence of a few ppm of H 2 S at 700uC. In this, first detailed study of the influence of H 2 S on carbon morphology on SS304H, we show that the addition of H 2 S greatly altered the carbon morphology, in the long-term experiments (90 h). For shorter exposure times (4 h), carbon formation decreased as H 2 S concentration was increased. This improved carbon tolerance of SS304H is likely due to adsorption of sulphfur on its surface. Addition of H 2 S did not change ethane cracking temperature or product distribution.

Role of Presulfidation and H2S Cofeeding on Carbon Formation on SS304 Alloy during the Ethane–Steam Cracking Process at 700 °C

“…The presulfided powder shows a weak sulfur (S 2p) signal relative to the background signal measured for the preoxidized SS304L powder. XPS analysis of a SS304H coupon exposed to ethane–steam and 1 ppm of H 2 S also showed similar results, with a S 2p peak at a binding energy of 169.29 eV . The binding energy of this peak is consistent with S in a sulfate group.…”