Thermodynamic analysis of theoretical dolomite formation from seawater and captured carbon dioxide

In this study, an integrated system is proposed to form dolomite chemically from seawater and carbon dioxide. The system contains three main chemical processes: formation of magnesium hydroxide and calcium hydroxide, the reaction of magnesium hydroxide and calcium hydroxide with carbon dioxide, and the formation of dolomite. Based on the fundamental thermodynamic laws, energy and exergy analyses, and performance assessment of the proposed system is carried out. Furthermore, the effects of varying temperatures of each process on various energy and exergy efficiencies are assessed through parametric studies. The results show that formation of dolomite is favorable at temperature ranges of 313–470 K based on the thermodynamic study. The exergy efficiency of dolomite formation is found to be about 23.8% and the results reveal that the dolomite formation process has the specific exergy destruction value of 29.6 kJ/mol among other sub-processes. The results suggest that the proposed system may provide enhanced options for low-temperature dolomite formation using seawater and captured carbon dioxide once the reaction kinetics is favored.