Thermodynamic analysis and power requirements of CO2 capture, transportation, and storage in the ocean

Carbon capture and storage entails a series of processes for carbon dioxide: separation from the other combustion gases and sequestration; pressurization; transportation; storage; and monitoring. Each one of these processes requires significant quantities of energy. This article offers a holistic view of carbon capture and storage by examining all the processes involved and calculating their work requirements. In addition, the article derives the minimum work (exergy) for separation, which applies to all the separation processes - mechanical, chemical, electrical, etc. This benchmark work is 106.8 kJ/kg for carbon dioxide. A case study is performed for a 1 GW (nominal) coal power plant that is currently in operation. The calculations show that carbon dioxide must be transported in a supercritical state, and that the separation and compression of this gas requires the expense of significant energy. The absolute minimum power requirements for capture, transportation and storage of the produced CO2 account for approximately 16% of the net power generated by the power plant, while the actual power requirements - using current technology and realistic equipment efficiencies - are close to 58% of the generated power. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Carbon capture and storage involves a series of processes including separation, pressurization, transportation, storage, and monitoring, each requiring significant energy. The article calculates the minimum work requirements for separation processes and conducts a case study on a coal power plant, finding that actual energy requirements are much higher than the minimum power.