Overview on CO2 Valorization: Challenge of Molten Carbonates

Chery, Déborah; Lair, Virginie; Cassir, M.

doi:10.3389/fenrg.2015.00043

Cited by 61 publications

(43 citation statements)

References 59 publications

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“…In economic terms, however, the brightest outlook for carbonate technologies concerns electrochemistry, with applications in molten carbonate fuel cells (MCFC) 12,13,50,51 and in high capacity rechargeable batteries. 14 Molten carbonate fuel cells, moreover, can be coupled to CO 2 capture and sequestration stages, 15,16 enhancing the efficiency and the environmental appeal of these devices. Many other applications are being considered, including recent attempts to develop efficient thermoelectric energy converters based on ionic conductors, 17 and the usage of molten alkali-carbonates as the solvation medium for photovoltaic processes powered by concentrated solar radiation.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulations of Metal/Molten Alkali Carbonate Interfaces

et al. 2017

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Interfaces between molten carbonates M 2 CO 3 (M=Li, Na and K) and planar metal walls have been investigated by molecular dynamics based on a rigid-ions force field (Janssen and Tissen, Mol. Simul. 5, 83-98, (1990)). Simulations cover the temperature range 1200 K ≤ T ≤ 1500 K at a moderate (∼ 15 kbar) overpressure to compensate for a slight overestimate of the system volume by the force field model. Most of the simulations represent neutral electrodes, but shorter computations have been carried out for systems with a low surface charge distribution on the metal side of the interface. The results provide an intriguing view of the interplay among ion packing, oscillating screening, anisotropic correlations and ion dynamics at the interface. The mass and charge density profiles display prominent peaks at contact, and tend to their constant bulk values through several oscillations, whose amplitude decays exponentially moving away from the interface.Oscillations in the charge density profile, in particular, limit the value of the interfacial dipole, and increase the capacitance of the interface. Ion-ion correlations are enhanced in proximity of the metal surface, but retain the exponentially-decaying oscillatory form of their bulk counterpart.Diffusion is slower in the molecularly thin layer of ions next to the interface than in the bulk.The analysis of interfaces is completed by the computation of structural properties of bulk phases, and by the estimate of transport coefficients such as self-diffusion, electrical conductivity, and especially thermal conductivity, which is seldom computed by simulation. All together, the results of our simulations for homogeneous and inhomogeneous molten carbonates provide crucial insight on systems and properties relevant for advanced devices such as fuel cells, that, in turn, might play a prominent role in future power generation strategies.

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Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulations of Metal/Molten Alkali Carbonate Interfaces

et al. 2017

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“…It could even decrease because of additional losses from 0.1%-8% during the upgrading, depending on the treatment process [38]. However, it could increase if the cleaned CO 2 share is used as a resource in further technological processes [8,39,40]. As the following example shows, upgrading biogas to bio-methane and utilization of the separated CO 2 could increase the overall CUDe up to 86.5% ( Figure 2).…”

Section: Carbon Utilization Degree Of a Biomass Transformation To Biomentioning

confidence: 99%

CUDe—Carbon Utilization Degree as an Indicator for Sustainable Biomass Use

et al. 2016

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Carbon (C) is a central element in organic compounds and is an indispensable resource for life. It is also an essential production factor in bio-based economies, where biomass serves many purposes, including energy generation and material production. Biomass conversion is a common case of transformation between different carbon-containing compounds. At each transformation step, C might be lost. To optimize the C use, the C flows from raw materials to end products must be understood. The estimation of how much of the initial C in the feedstock remains in consumable products and delivers services provides an indication of the C use efficiency. We define this concept as Carbon Utilization Degree (CUDe) and apply it to two biomass uses: biogas production and hemp insulation. CUDe increases when conversion processes are optimized, i.e., residues are harnessed and/or losses are minimized. We propose CUDe as a complementary approach for policy design to assess C as an asset for bio-based production. This may lead to a paradigm shift to see C as a resource that requires sustainable exploitation. It could complement the existing methods that focus solely on the climate impact of carbon.

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“…In fact, the MCFC can be employed to separate CO 2 from a gaseous stream, as a consequence of CO 3 2− ions being the charge carriers in the fuel-cell carbonate electrolyte that selectively transports CO 2 from the cathode to the anode half-cells. When processed through a MCFC, the flue gas of a power plant will be stripped of most of the initial CO 2 content, whereas the CO 2 balance (up to 70%) will have been transferred to the smaller and concentrated anode exhaust stream [44]. There it can more easily be separated into purified CO 2 .…”

Section: Point Source Capturementioning

confidence: 99%

The Role of Synthetic Fuels for a Carbon Neutral Economy

Rosa

2017

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Fossil fuels depletion and increasing environmental impacts arising from their use call for seeking growing supplies from renewable and nuclear primary energy sources. However, it is necessary to simultaneously attend to both the electrical power needs and the specificities of the transport and industrial sector requirements. A major question posed by the shift away from traditional fossil fuels towards renewable energy sources lies in matching the power demand with the daily and seasonal oscillation and the intermittency of these natural energy fluxes. Huge energy storage requirements become necessary or otherwise the decline of the power factor of both the renewable and conventional generation would mean loss of resources. On the other hand, liquid and gaseous fuels, for which there is vast storage and distribution capacity available, appear essential to supply the transport sector for a very long time ahead, besides their domestic and industrial roles. Within this context, the present assessment suggests that proven technologies and sound tested principles are available to develop an integrated energy system, relying on synthetic fuels. These would incorporate carbon capture and utilization in a closed carbon cycle, progressively relying mostly on solar and/or nuclear primary sources, providing both electric power and gaseous/liquid hydrocarbon fuels, having ample storage capacity, and able to timely satisfy all forms of energy demand. The principles and means are already available to develop a carbon-neutral synthetic fuel economy.

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Overview on CO2 Valorization: Challenge of Molten Carbonates

Cited by 61 publications

References 59 publications

Molecular Dynamics Simulations of Metal/Molten Alkali Carbonate Interfaces

Molecular Dynamics Simulations of Metal/Molten Alkali Carbonate Interfaces

CUDe—Carbon Utilization Degree as an Indicator for Sustainable Biomass Use

The Role of Synthetic Fuels for a Carbon Neutral Economy

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