Mineralization for carbon dioxide sequestration using olivine sorbent in the presence of water vapor

Mineralization has the potential to capture CO2. In nature, mineralization is the chemical weathering of alkaline-earth minerals in which stable carbonate minerals are formed, which leads to the removal of CO2 from the atmosphere. The adsorptive carbonation reaction of olivine [(Mg,Fe)2SiO4)], consisting mainly of pure magnesium silicate (Mg2SiO4), a main constituent of the Earth's crust, was carried out to estimate its potential application in the separation of CO2 with the presence of water vapor in combustion plumes.;This thesis first presents a review of the literature pertaining to various CO2 capture technologies and the evaluation of their performance. The review mainly describes the application of CO2 adsorption on various solid sorbents that capture CO2, including mineral carbonation. In addition, it includes the selection of minerals and the mineralization processes. Following the review, this thesis presents an experimental set-up and analyses in this study. It also describes the experimental apparatus and procedures used to acquire information about CO2 capture capacities.;Experiments were mainly performed on pure Mg2SiO4 carbonation to determine the reaction properties, temperature effects, and cyclic adsorption, and to evaluate a reaction kinetics model. Based on the changes in the CO 2 concentration with sorption time, a kinetic model of the reaction between Mg2SiO4 and CO2 was developed. The reaction order with respect to CO2 was approximately 1. Based on the changes in the reaction rates with temperature in the range of 150ºC to 200ºC, the activation energy derived for the Arrhenius equation of Mg2SiO4-based carbonation process is 76.2 +/- 4.8 kJ/mol.;To evaluate the application of natural olivine for CO2 sequestration, experiments were conducted on natural olivine mineralization in the presence/absence of water vapor under various conditions of temperature, concentration, and space time. Based on calculations, the olivine carbonation reaction is thermodynamically favorable. Water vapor was found to play an important role in accelerating the carbonation rate, and experimental results revealed that carbon dioxide can combine with olivine minerals to form highly stable surface carbonates.;To investigate the molecular reaction mechanism and adsorption configuration of CO2 adsorption on the metal oxide surface, we performed a quantum chemistry calculation of multiple CO2 adsorption on a CaO (100) surface due to higher reactivity for CO2 adsorption than MgO. In the formation of a monolayer, CO2 molecules were chemi-sorbed due to the charge reorganization between the CaO surface and CO2 molecules. The adsorbed CO2 molecules got together rather than distributing uniformly over the CaO surface. The second layer adsorption can take place at ambient condition and characterized as the physi-sorption.;Consequently, this study helps lay the groundwork for the chemical mechanism of mineral carbonation of olivine with carbon dioxide in the presence of water vapor and provides the relevant information for the real application of the olivine based CO2 separation.