SABIC EXPERIENCE FROM ANTI-COKING COILS IN STEAM CRACKERS AND METHODOLOGY OF BENEFITS QUANTIFICATION

摘要

Although ethylene plants are well established,there are plethora of challenges that ethylene producers are facing.Furnace run length and availability are on top of this list.As mitigation and in line with its 2025 strategy,SABIC has been deploying Anti-Coking Technologies (ACT) in the recent years in its ethylene plants to maximize production and improve energy intensity.Anti-coking improvements cover developments of chemical additives,flow-modifiers,furnace tube coatings and enhanced alloys.All of these technologies work in different mechanisms to reduce coke formation,which will benefit the plant by extending furnace run length,improving furnace availability,reducing decoking cycles and hence increase profitability.Among these,anti-coking coils (enhanced aluminum based alloys) work in reducing catalytic coke formation and the carburization effects by forming a protective layer,which shields the catalytic sites.This paper illustrates SABIC experience in evaluating and implementing different technologies,and the methodology of benefits quantification from ACT to justify the investment cost in its furnaces.SABIC has over 100 furnaces in Saudi Arabia where more than 30 furnaces have upgraded coils to different enhanced alloys.Moreover,various anti-coking technologies implemented in SABIC crackers from several vendors have been investigated,analyzed,and compared.Multitudes of benefits have been reported depending on several factors such as alloy selection,furnace limitation,downstream limitation,feedstock type and availability.