Abstract: To address the structural market conflict between declining diesel demand and shortage of ethylene feedstock, technical schemes for converting different types of diesel fractions into high-quality ethylene cracking feedstocks via hydro-upgrading technology were investigated. The processing strategies for different fractions (kerosene, diesel) derived from paraffinic Saudi Lightcrude oil and intermediate-based Shengli crude oil were emphasized. The results show that for paraffinic Saudi Light crude oil, the light fraction with a final boiling point ＜200°C has high paraffin content (62%) and can be directly used as ethylene feedstock. For its 200—250°C jet fuel fraction, at a conversion rate of 10%, the BMCI value of the unconverted oil (UCO) decreases to 16.2 with paraffin content reaching 55.4%. For its 250—350°C diesel fraction, at a conversion rate ＞10%, the BMCI of UCOdecreases to below 21 and paraffin content exceeds 50%, becoming suitable ethylene feedstocks. For intermediate-based Shengli crude oil, <150℃ light fractions are more suitable for reforming feedstock. Its 150—250 °C jet fuel fraction achieves a UCO BMCI of 23.2 and paraffin content of 50.5% at conversion of 15%, becoming suitable ethylene feedstocks. Its 250—350 °C diesel fraction requires narrow fractionation (recommended initial boiling point of 220—240°C) of the UCO after 20% conversion; the resulting ＞220°C or ＞240°C fraction exhibits significantly reduced BMCI and increased paraffin content, meeting ethylene feedstock requirements.

Key words: paraffinic crude oil, intermediate-based crude oil, hydro-upgrading, ethylene feedstock