Authors:
Jiajie Wang
;
Kengo Nakamura
;
Noriaki Watanabe
;
Atsushi Okamoto
and
Takeshi Komai
Affiliation:
Graduate School of Environmental Studies, Tohoku University, Aramaki, Aoba-Ku, Sendai and Japan, Japan
Keyword(s):
H2 production, CO2 storage, Rock-water reaction, Olivine, CO2-rich.
Abstract:
Hydration of olivine ((Mg,Fe)2SiO4) potentially offers significant H2 supply. However, because of the low Fe(II) dissolution rate, H2 production rate is poorly limited. In the present study, to investigate the CO2 effect on H2 generation and minerals evolution, CO2-rich (0.5 mol/L NaHCO3) reaction condition was created in the ongoing olivine hydration experiment. H2 production was continuing with a slight increasing rate after CO2 addition. Results indicate CO2-rich hydrothermal reaction condition (300 oC, 10 MPa) promoted both olivine and brucite (Mg,Fe(OH)2) dissolution, which led to additional Fe(II) releasing, and consequent H2 generation. CO2 was simultaneous hydrogenated to formic acid (HCOOH) by generated H2 and carbonated to magnesite (MgCO3). 0.52 mol of CO2 was trapped in per kg of olivine in 72 h. This study suggests simultaneous multiple energy productions and CO2 storage can be realized by olivine weathering process when using a CO2-rich hydrothermal condition.