Eco-Friendly and Economical: Underground Storage Space of Carbon Captured Directly From Air
A new research shows that geological storage of low purity carbon dioxide associated with oxygen and nitrogen of direct air capture is an environmentally and financially feasible techniques to remove carbon from the environment.
The recurring international threat of environmental adjustment has one main cause: carbon hidden underground in the form of fossil fuels is being removed and released directly into the atmosphere in the form of carbon dioxide (CO2). One promising way to solve this problem is carbon capture and storage space: the use of technology to remove CO2 from the environment to return it to the subsurface..
Greenhouse Gases Scientific Research and Innovation, scientists from Kyushu University and the National Institute of Advanced Industrial Science and Innovation, Japan, evaluated the geological storage space of low-purity CO2 combined with nitrogen (N2) and oxygen (O2), produced by direct air capture (DAC) using membrane-based innovation.
At the moment, a considerable number of projects related to carbon capture are being carried out on localised sources using focused CO2 emissions, such as coal-fired nuclear power plants, and require intensive purification storage space due to hazardous substances such as nitrogen oxide and sulphur oxide. They also have expensive transport prices, as practicable geological storage sites are usually a long way from the CO2 sources. On another side, direct capture of carbon dioxide can be performed anywhere on the storage site and does not require extensive filtration because the impurities, O2 and N2, are not unsafe. As an outcome, low purity CO2 can be seized and injected directly into geological developments, at least theoretically. Acknowledging how the resulting mixture of CO2, O2, and N2 behaves when infused and stored in geological structures is necessary before underground storage of low-purity CO2 from direct air sequestration may become widely embraced.
As the lead writer of the research, Professor Takeshi Tsuji, discusses the difficulty of capturing high purity carbon dioxide using DAC. Takeshi mentioned that he and his team performed molecular dynamic simulations as a preliminary evaluation of the storage effectiveness of CO2-N2-O2 combinations at three different temperature and stress problems, corresponding to depths of 1,000 m, 1,500 m, and 2,500 m at the Tomakomai CO2 storage site in Japan.
Although additional studies are still required, such as investigations of the chemical reactions of O2 and N2 infused at incredible depths, the results of these simulations recommend that geological storage of CO2-N2-O2 combines created by direct air capture is both free of ecological risks and economically feasible.
Professor Tsuji says, due to the ubiquity of ambient air, direct air capture has the potential to become a ubiquitous form of carbon capture and storage that can be implemented in many remote locations such as deserts and offshore platforms. This is very relevant both to lower transport prices and to ensure social acceptance.
Reference: “Geological storage of CO2–N2–O2 mixtures produced by membrane-based direct air capture (DAC)” by Takeshi Tsuji, Masao Sorai, Masashige Shiga, Shigenori Fujikawa, Toyoki Kunitake, 1 June 2021, Greenhouse Gases: Science and Technology.
DOI: 10.1002/ghg.2099
