Abstract: To achieve cost reduction and efficiency improvement in the steam cracking unit, crude oil was introduced as a partial substitute for conventional cracking feedstocks. Due to the high sulfur content in crude oil, process innovation was required to mitigate the adverse effects of increased sulfur content in cracking products. Based on in-depth calculations, the impact of selecting regeneration gas media for the new desulfurization adsorption bed and the increased sulfur content on the safe and stable operation of the unit was analyzed. The results indicate that a crude oil blend with an Akpo-WTI mass ratio of 3:7 is suitable as a cracking feedstock, capable of replacing 51.6% of conventional feedstocks and significantly reducing external procurement costs. After introducing crude oil as a feedstock, cracking gas not only showed a significant increase in hydrogen sulfide (H₂S) content but also contained carbonyl sulfide (COS) and carbon disulfide (CS₂), necessitating the addition of a desulfurization adsorption bed for cracking gas treatment. Recycled ethane was preferred as the regeneration medium for desulfurization adsorbents in C₃ and lighter fractions and mixed C₄ products, as opposed to self-produced fuel gas, which is unsuitable due to its moisture content that can create a wet H₂S corrosion environment and may lead to excessive sulfur emissions in flue gas. The increased sulfur content adversely affects the cracking gas compressor unit but has no impact on the caustic washing system. For carbon steel components in wet H₂S corrosion environments, post-weld heat treatment is required to mitigate corrosion risks.

Key words: crude oil steam cracking, light olefins, cracked gas, sulfur impurity, desulfurization adsorption catalyst, regeneration medium, wet hydrogen sulfide corrosion