Ripple effects of defossilising aromatics production in petrochemical clusters

Abstract

Over 50% of the feedstock carbon in petrochemical clusters stems from the production of high-volume chemicals like benzene and p-xylene. These are typically produced from fossil-based carbon sources within highly integrated systems, where mass and energy flows are tightly interconnected. Transitioning to alternative carbon sources (ACS) can significantly disrupt these interactions, an aspect that is overlooked in existing literature. This paper addresses this knowledge gap by evaluating the impact of replacing fossil-based benzene production with ACS-based routes using CO2, biomass, and plastic waste. It explicitly evaluates performance at both the process and cluster levels by assessing changes in mass, energy, prices, CO2 emissions, and water demand. The results show that due to differences in product distribution, energy requirements, and waste generation, ACS-based processes can trigger unintended ripple effects across downstream units, utility providers, and waste treatment plants. Among the evaluated options, plastic waste-based benzene emerges as the most competitive technology under current market conditions, with the lowest impact at the cluster level. However, its viability depends on the availability of plastic waste, which is a constraint given current recycling rates. Further improvements in waste valorisation and integrating renewable heat are essential to improve the environmental performance of this technology.