Carbon capture and utilization: preliminary life cycle CO_2, energy, and cost results of potential mineral carbonation

摘要

Mineral carbonation has been identified as a potentially suitable means of CO_2 sequestration in Singapore due to the nation's lack of land for geological or deep ocean storage of CO_2. In this article, the total energy, CO2 emissions and costs of mineral carbonation are investigated using a life cycle assessment (LCA) approach. The life cycle investigation took into account energy and greenhouse gas emissions from mineral mining activities and shipment, the recovery of CO_2 based on amine scrubbing technology and simulated scenarios of the net energy requirements for the carbonation process based on 'ideal' and worst case energy requirements. The CO_2 avoided results from a total of 4 scenarios were in the range of 106.9 kg to 175.9 kg per 1 MWh. The percentage sequestration effectiveness results are from 32.9% to 49.7%. The life cycle costing results are 105.6 USD/tonne CO_2 avoided and 127.2 USD/tonne CO_2 avoided for two of the most favorable scenarios. However, it is highlighted that various engineering challenges have to be overcome before the 'ideal' carbonation reaction conditions represented in the simulation model can be achieved. The results will most likely fluctuate somewhere between the ideal and worst case conditions. The main energy penalties and associated CO_2 emissions come mostly from CO_2 recovery, pretreatment and mineralization process itself.