Simultaneous Olivine Alteration and Carbonation in CO2-Rich Geological Condition
- Jiajie Wang (Tohoku University) | Kengo Nakamura (Tohoku University) | Noriaki Watanabe (Tohoku University) | Takeshi Komai (Tohoku University)
- Document ID
- International Society of Offshore and Polar Engineers
- The 28th International Ocean and Polar Engineering Conference, 10-15 June, Sapporo, Japan
- Publication Date
- Document Type
- Conference Paper
- 2018. International Society of Offshore and Polar Engineers
- serpentinization, carbonation, Olivine alteration, carbon-rich, hydrothermal
- 2 in the last 30 days
- 27 since 2007
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To investigate the mineral change and energy output of the olivine hydration and carbonation processes in carbon rich hydrothermal system, we monitored a reaction between olivine and NaHCO3 fluid at 300 °C and 10 MPa. The study showed the addition of NaHCO3 can promote both the olivine alteration and carbonation process. H2 and HCOOH were regarded as the energy output, with the highest yield of 1.13 mmol and 6.45 mmol/L achieved at 1.0 mol/L of NHCO3 solution in 72 h. Addition of NaOH promotes brucite generation. The whole process was simulated by kinetic pseudo-second-order model.
The high energy demand in the 21st century will cause severe energy crisis and huge carbon dioxide (CO2) emission which aggravating the greenhouse effect. In 2016, the atmospheric concentration of CO2 is 403.3 ppm, having increased by 45% compared with the pre-industrial level of 280 ppm and still increasing at a rate of 2 ppm per year. Controlling the global warming and exploring renewable or non-carbon-based energy sources are the main scientific and technological challenges facing the humanity in the 21st century. These has encouraged a significant amount of researches in the field of carbon capture, utilization and storage (CCUS) (Sakakura et al., 2007). Compare to carbon capture and sequestration (CCS), CCUS is more favorable over a long time span as CO2 can be converted to renewable energy.
In recent years, after the discovery of light hydrocarbons in several fluids from hydrothermal environment such as the Mid-Atlantic Ridge (Kelley et al., 2001; Proskurowski et al., 2008) and East Pacific Rise (Charlou et al., 1996), the abiotic origin of hydrocarbon was confirmed. This finding gives a new idea for CO2 treatment. The CO2 contamination was supposed to be relieved by natural hydrothermal reduction with the generation of energy substance (usually refers to some organic matters, e.g. HCOOH, CH4 or other hydrocarbon). The abiotic organic matters were mostly cited be synthesized by H2 reduction according to Fischer-Tropsch synthesis mechanism.
H2 has been widely regarded as the potential energy source with a high gravimetric energy density of 33.3 kW•h/kg, and can also be used to reduce CO2. In geological environments, H2 can be generated by the interactions between water and ferrous Fe-bearing minerals (e.g. olivine, pyroxene and pyrrhotite) which has been found with a concentration as high as 16 mmol/kg (Charlou et al., 2000, 2002; Kelley et al., 2005; Evans et al., 1988).
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