Abstract
Carbon Capture and Utilisation (CCU) is the technology of capturing CO2 from point sources or ambient air and converting it into valuable products such as ethylene, methanol, formic acid, or urea. The production processes of ethylene by the electrochemical reduction of captured CO2 emanating from the quicklime plant have been analysed in this study. The conventional method of ethylene production is the steam cracking of hydrocarbon feedstock, usually natural gas, naphtha or ethane. The environmental footprints of those conventional processes have been reviewed from secondary sources. The main objective of this study is to quantify the carbon and other environmental footprints of the ethylene product derived from a CO2-rich gas stream. The evaluation of environmental footprints for 1 kg of ethylene production has been performed using SimaPro 9.5.0.0 Life Cycle Assessment (LCA) software tool considering the impact assessment methodology IMPACT World+ Midpoint version 1.03 based on the inventoried data of carbon capture & delivery, integrated electrolyser cell and product gases separation processes. The LCA tool calculated 18 mid-point damage categories, including climate change footprint. It is reported that the overall climate change footprint of the CO2 captured electroreduction processes is about - 0.834 kg CO2 eq per kg of ethylene and demonstrated the reduction of that environmental impact by 110 - 120 % compared to the conventional processes.
