Reducing CO2 emissions of existing ethylene plants: Evaluation of different revamp strategies to reduce global CO2 emission by 100 million tonnes

Steam cracking is the leading technology to produce light olefins and the most energy-consuming process in the chemical industry, using approximately 10% of the sector's total primary energy globally. Six technological improvements, requiring limited hardware changes and implementable today, have been evaluated: high emissivity coatings, 3D reactor designs, advanced coil material, oxy-fuel combustion, carbon capture and storage (CCS), and biogas firing. These technologies have the potential to reduce both energy consumption and raw material demand. Life cycle inventory data are obtained from the first principles-based COILSIM1D model of the furnaces, validated with industrial data, combined with a Petro-SIM model of the overall mass and energy balance of the plant. Cradle-to-gate life cycle assessment (LCA) shows that a major contribution to the overall carbon footprint of light figureolefin production is related to the feedstock supply. Oxy-fuel combustion combined with CCS followed by biofuel combustion has the highest potential to reduce the carbon footprint, and reach a target of over 100 × 106 metric tons/yr of CO2 eq. worldwide. On the other hand a combination of radiant coatings and novel reactor coil design yields in a marginal 0.5% reduction or potentially 3 × 106 metric tons/yr of CO2 eq. worldwide. In order to decrease the carbon footprint more one would have to consider both substantial hardware changes - requiring a large investment - and the use of non-fossil derived feedstocks.