Coke Formation Reduction in the Steam Cracking of Naphtha on Industrial Alloy Steels Using Sulfur-Based Inhibitors

Coke formation reduction during naphtha pyrolysis was investigated using dimethyl disulfide (DMDS) and carbon disulfide (CS2) as inhibitors with different feed stocks. Different industrial nickel alloy steels such as stainless steel 304 and 316 (SS304, SS316), HP-modified (HP-mod) and HP-micro (HP-mic) were used as coupons in a quartz cylindrical reactor for coke formation studies. Coke formation significantly reduced in the presence of the additives or using feeds with more sulfur compounds. It was revealed that HP-mic alloy has the least coke deposition rate between other alloys. Scanning electron microscope (SEM) and energy dispersive X-ray analyzer (EDAX) were used for morphological and elemental surface analyses, respectively. It was found that cokes formed in presence of sulfurous inhibitors are softer and have less metal concentrations.