A practical approach to near-term decarbonization of the ethylene plant

Joint Paper by Technip Energies & Mitsubishi Heavy Industries

With the petrochemical industry’s increasing focus on reducing the carbon footprint of their respective plants, nearly all industry players worldwide want to achieve carbon neutrality as soon as possible. However, achieving net-zero emissions requires numerous advanced technologies which are currently in development and may not be commercially viable on an industrial scale for another fifteen to twenty years. Hence, producers will need to employ transition technologies that are available today to decarbonize their respective plants during the interim. This study is mainly focused on exploring these transition technologies to reduce carbon footprint in a cost-effective manner and their consequent ethylene plant arrangements.

The paper starts by presenting a typical ethylene plant which will act as the ‘base plant’ for this case study. Then, a ‘low-emission’ ethylene plant is introduced which employs a new cracking furnace technology having the potential to reduce the requirement of fuel (natural gas, in this case) by nearly 25%. This, in turn, reduces the amount of carbon dioxide produced by the ‘low-emission’ plant up to 25%. Next, the study discusses the key design features of this ‘low emission’ furnace and the resulting reduction in the amount of Super High Pressure (SHP) steam produced in the plant.

Since the amount of available SHP steam is less in the ‘low emission’ plant, all the compressor trains cannot be driven by steam turbine drivers alone (as it had been the case in typical plants). So, there is an opportunity for electrification of the ethylene plant. Two cases employing a combination of Steam Turbine compressor drivers and Electric Motor compressor drivers are analyzed and compared with the ‘base plant’. Impact to the utility balances and carbon footprint of the studied plant configurations are summarized in order to provide a holistic picture of the ‘low-emission’ plant.

Thereafter, the study evaluates the ‘low-emission’ plant and ‘base plant’ on the parameters of costs such as piping, rotating equipment, new cracking furnace, etc. and maintenance/reliability. Further suggestions to reduce cost are also involved in this study. Finally, the paper is concluded by providing recommendations on how this ‘low-emission’ configuration can be implemented by a petrochemical company in a practical and economical way.