ATOMIC-LEVEL MODELING OF CO2 DISPOSAL AS A CARBONATE MINERAL: A SYNERGETIC APPROACH TO OPTIMIZING REACTION PROCESS DESIGN
Fossil fuels, especially coal, can support the energy demands of the world for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Permanent and safe methods for CO{sub 2} capture and disposal/storage need to be developed. Mineralization of stationary-source CO{sub 2} emissions as carbonates can provide such safe capture and long-term sequestration. Mg-rich lamellar hydroxide mineral carbonation is a leading process candidate, which generates the stable naturally occurring mineral magnesite (MgCO{sub 3}) and water. Key to process cost and viability are the carbonation reaction rate and its degree of completion. This process, which involves simultaneous dehydroxylation and carbonation is very promising, but far from optimized. In order to optimize the dehydroxylation/carbonation process, an atomic-level understanding of the mechanisms involved is needed. In this investigation Mg(OH){sub 2} was selected as a model Mg-rich lamellar hydrocide carbonation feedstock material due to its chemical and structural simplicity. Since Mg(OH){sub 2} dehydroxylation is intimately associated with the carbonation process, its mechanisms are also of direct interest in understanding and optimizing the process. The aim of the current innovative concepts project is to develop a specialized advanced computational methodology to complement the ongoing experimental inquiry of the atomic level processes involved in CO{sub 2} mineral sequestration. The ultimate goal is to integrate the insights provided by detailed predictive simulations with the data obtained from optical microscopy, FESEM, ion beam analysis, SIMS, TGA, Raman, XRD, and C and H elemental analysis. The modeling studies are specifically designed to enhance the synergism with, and complement the analysis of, existing mineral-CO{sub 2} reaction process studies being carried out under DOE UCR Grant DE-FG2698-FT40112. Direct contact between the simulations and the experimental measurements is provided by computing, from first principles, the equilibrium structures, elastic, optical, and vibrational properties of Mg(OH){sub 2} (brucite), MgO (periclase), MgCO{sub 3} (magnesite), as well as the energetics of the dehydroxylation reaction (Mg(OH){sub 2} {yields} MgO + H{sub 2}O), and the reactivity of CO{sub 2} with MgO and Mg(OH){sub 2}. From these calculations, thermodynamic characteristics of the reaction conditions can be inferred. This kind of information, when integrated with the atomic level data obtained from experimental gas-solid dehydroxylation/carbonation studies, will be used to design optimized reaction processes leading to the practical and cost-effective sequestration of CO{sub 2} in mineral form.
- Research Organization:
- National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- FG26-99FT40580
- OSTI ID:
- 791496
- Report Number(s):
- FG26-99FT40580-01; TRN: US200204%%35
- Resource Relation:
- Other Information: PBD: 1 Nov 2001
- Country of Publication:
- United States
- Language:
- English
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ATOMIC-LEVEL IMAGING OF CO2 DISPOSAL AS A CARBONATE MINERAL: OPTIMIZING REACTION PROCESS DESIGN
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