Experimental study and kinetic modeling of high temperature and pressure CO2 mineralization.

• Experiment at upper-temperature limit for CO 2 sequestration in basalt. • CO 2 sequestration experiment in metasedimentary rocks. • PHREEQC modeling compared to experimental results. • Numerical models might overestimate CO 2 sequestration at high temperatures. The potential for in-situ CO 2 sequestration was analyzed experimentally for one basaltic hyaloclastite sample from the Nesjavellir geothermal reservoir in Iceland and three metasedimentary rock samples from the Kızıldere geothermal field in Turkey. Based on batch reaction experiments, this paper demonstrates the interaction between a CO 2 gas-charged fluid and rock samples from these reservoirs. The experiments were conducted at 260 °C and 0.8 MPa, and 105 °C and 17 MPa for the basaltic and metasedimentary rocks, respectively. The experimental results indicate that CO 2 sequestration within the glassy basaltic rocks is hampered by zeolite, chlorite, and anhydrite, which compete with carbonate minerals to uptake divalent cations at the P-T conditions applied. In contrast, the carbonation process for the metasedimentary rocks is inhibited by their mineralogical composition. Generally, these rocks are less reactive and provide an insufficient supply of divalent cations. The batch reactor experiments were numerically simulated with the PHREEQC geochemical modeling program. The simulations indicate that CO 2 sequestration is feasible at the tested P-T conditions, provided that silicate and SO 4 mineralization is suppressed for the basaltic rocks and that there is an effective source of divalent cations for the metasedimentary rocks. [ABSTRACT FROM AUTHOR]