Research progress on key technologies of CO2 storage in basalts

Abstract

Geological storage of CO2 in basalts provides a new and potentially significant option for carbon capture and storage (CCS). So far, there are only three demonstration projects in the world, namely Nagaoka in Japan, Wallula in the United States of America and Carbfix in Iceland. These examples have confirmed the technical and economic feasibility of geological storage of CO2 in basalts. The main progress achieved on the technology of CO2 capture and storage in basalts are as follows (1) CO2 in flue gas can be better captured by using aqueous solution instead of amine solvent, so that CO2 and other water-soluble gases are easily captured at the same time, while equipment such as scrubbing tower is just simply installed as a gas separation device near the emission point source. (2) The Carbfix method suitable for CO2 saturated solution injection and storage is proposed, and a special system which can inject gas and water solution respectively is designed. (3) In the process of CO2 injection and sequestration, the tracer element monitoring method was firstly adopted, and the percentage of carbonation of CO2 injected was quantitatively estimated by the mass balance method. It was found that at least 95% of basalts were completely mineralized in less than two years after CO2 injection. However, the remain technical problems exist and need to be further studied, which include (1) how to choose the correct injection means between the CO2 saturated and supercritical solutions. (2) Whether sea water can replace fresh water to dissolve CO2. (3) How to improve the accuracy of geochemical simulation of injection and geological storage of CO2 in basalts. (4) How to reduce the cost of carbon capture, separation and transportation. There are still a long way to go before we can effectively deploy such CCS technologies throughout the world.

Keywords

• basalts
• carbon dioxide
• carbon capture and storage
• injection
• monitoring