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Control of Emissions from Stationary Sources
Published in Wayne T. Davis, Joshua S. Fu, Thad Godish, Air Quality, 2021
Wayne T. Davis, Joshua S. Fu, Thad Godish
In 2017, based on pilot studies, a consortium of international organizations and universities developed an initiative to capture CO2 at the Hellisheidi Power Plant in Iceland. The geothermal power plant is located on the Hengill volcano and is Iceland’s largest geothermal plant. The program, referred to as CarbFix, captures about one-third of the CO2 emissions from the steam at the plant. It absorbs the CO2 into water (which is abundant in Iceland) at low concentrations at a ratio of about 4% CO2 by weight (a process described as being similar to carbonated drinks). The liquid is then pumped into the underlying basalt volcanic rock where it reacts with the calcium, magnesium, and iron to form additional rock. While the CarbFix plant is small and captures about 10,000 metric tons per year, it demonstrates the ability to capture and permanently store carbon in areas where basaltic rock is present. A similar technology, referred to as CarbonCure™ in the United States, diverts CO2 captured from or present at industrial sources to concrete plants where it is injected as an aqueous mix into cementitious material, to form concrete for use in building materials and other concrete uses. In early 2020, it was reported that the technology was continuing to grow and had already captured 62,000 metric tons.
The technology of CO2 sequestration by mineral carbonation: current status and future prospects
Published in Canadian Metallurgical Quarterly, 2018
F. Wang, D. B. Dreisinger, M. Jarvis, T. Hitchins
Thus far, the most successful and the most important in situ MC by basalts is the CarbFix pilot project in Iceland. This project is a cooperation between Iceland and the U.K., the U.S.A., France, Netherlands, Australia, and Denmark [25–27] A CO2-H2S gas mixture was injected into a 2000-m-deep well. A total of 8 surveying wells ranging in depth from 150 to 1300 m, as shown in Figure 2 [25], were used to study the MC stability. During the in situ MC, the water temperature and pH are in the range from 20 °C to 33 °C and from 8.4 to 9.4 without oxygen, respectively [28]. The CO2 pressure was set to 200 bar. Furthermore, in order to prevent the CO2 gas leakage during injection, a novel CO2 injection system was developed by dissolving the gas mixture into down-flowing water into the well and keeping the CO2 concentration below its solubility at these conditions [29]. The isotopic analysis method was applied to monitor the MC process. The study demonstrated that permanent CO2 sequestration into carbonates through the in situ MC by basaltic rocks is possible. It was reported that 95% CO2 injected into CarbFix site has been mineralised in just less than 2 years [25]. Thus far, the CarbFix project has successfully sequestered 175 tons of pure CO2 and 73 tons of a CO2-H2S gas mixture [25]. Lu et al. also verified that O2 (up to 3.5% of the mixture gas) has no detrimental effect on the MC process [30], which means it is unnecessary to use pure CO2 gas. There are two main reasons for CarbFix’s success: First, CO2 gas was injected into basalts rather than sedimentary silicate rocks which are less reactive and contain less divalent metals than basalts; Second, CO2 gas was first dissolved into water and then the CO2-dissolved fluid was injected into the underground, which decreased the risk of releasing CO2 gas back up to atmosphere [31]. Based on CarbFix’s success, another in situ MC pilot project, Big Sky Regional Partnership, has been conducted in the Columbia River Basalt in the U.S.A. but through injecting pure CO2 underground, with the support of the CarbFix team (https://www.or.is/english/carbfix-project).