Since the time of the industrial revolution, the atmospheric CO(2) concentration has risen by nearly 35 % to its current level of 383 ppm. The increased carbon dioxide concentration in the atmosphere has been suggested to be a leading contributor to global climate change. To slow the increase, reductions in anthropogenic CO(2) emissions are necessary. Large emission point sources, such as fossil-fuel-based power generation facilities, are the first targets for these reductions. A benchmark, mature technology for the separation of dilute CO(2) from gas streams is via absorption with aqueous amines. However, the use of solid adsorbents is now being widely considered as an alternative, potentially less-energy-intensive separation technology. This Review describes the CO(2) adsorption behavior of several different classes of solid carbon dioxide adsorbents, including zeolites, activated carbons, calcium oxides, hydrotalcites, organic-inorganic hybrids, and metal-organic frameworks. These adsorbents are evaluated in terms of their equilibrium CO(2) capacities as well as other important parameters such as adsorption-desorption kinetics, operating windows, stability, and regenerability. The scope of currently available CO(2) adsorbents and their critical properties that will ultimately affect their incorporation into large-scale separation processes is presented.

Adsorbent Materials for Carbon Dioxide Capture from Large Anthropogenic Point Sources

Carbon capture and storage (CCS) is broadly recognised as having the potential to play a key role in meeting climate change targets, delivering low carbon heat and power, decarbonising industry and, more recently, its ability to facilitate the net removal of CO2 from the atmosphere. However, despite this broad consensus and its technical maturity, CCS has not yet been deployed on a scale commensurate with the ambitions articulated a decade ago. Thus, in this paper we review the current state-of-the-art of CO2 capture, transport, utilisation and storage from a multi-scale perspective, moving from the global to molecular scales. In light of the COP21 commitments to limit warming to less than 2 °C, we extend the remit of this study to include the key negative emissions technologies (NETs) of bioenergy with CCS (BECCS), and direct air capture (DAC). Cognisant of the non-technical barriers to deploying CCS, we reflect on recent experience from the UK's CCS commercialisation programme and consider the commercial and political barriers to the large-scale deployment of CCS. In all areas, we focus on identifying and clearly articulating the key research challenges that could usefully be addressed in the coming decade.

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Carbon capture and storage (CCS): the way forward

http://digital.csic.es/bitstream/10261/78793/1/Progress%20in%20chemical-looping%20combustion%20and%20ref....2012.pdf

Progress in chemical-looping combustion and reforming technologies

In recent years, Carbon Capture and Storage (Sequestration) (CCS) has been proposed as a potential method to allow the continued use of fossil-fuelled power stations whilst preventing emissions of CO2 from reaching the atmosphere. Gas, coal (and biomass)-fired power stations can respond to changes in demand more readily than many other sources of electricity production, hence the importance of retaining them as an option in the energy mix. Here, we review the leading CO2 capture technologies, available in the short and long term, and their technological maturity, before discussing CO2 transport and storage. Current pilot plants and demonstrations are highlighted, as is the importance of optimising the CCS system as a whole. Other topics briefly discussed include the viability of both the capture of CO2 from the air and CO2 reutilisation as climate change mitigation strategies. Finally, we discuss the economic and legal aspects of CCS.

Carbon capture and storage update

In this paper, three of the leading options for large scale CO2 capture are reviewed from a technical perspective. We consider solvent-based chemisorption techniques, carbonate looping technology, and the so-called oxyfuel process. For each technology option, we give an overview of the technology, listing advantages and disadvantages. Subsequently, a discussion of the level of technological maturity is presented, and we conclude by identifying current gaps in knowledge and suggest areas with significant scope for future work. We then discuss the suitability of using ionic liquids as novel, environmentally benign solvents with which to capture CO2. In addition, we consider alternatives to simply sequestering CO2—we present a discussion on the possibility of recycling captured CO2 and exploiting it as a C1 building block for the sustainable manufacture of polymers, fine chemicals, and liquid fuels. Finally, we present a discussion of relevant systems engineering methodologies in carbon capture system design.

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An overview of CO2 capture technologies

A new kind of Ca-based regenerable CO2 absorbent, CaO/ Ca12Al14O33, was synthesized on the basis of the integration of CaO, as solid reactant, with a composite metal oxide Ca12Al14O33, as a binder, for applying it to repeated calcination/carbonation cycles. The carbonation reaction can be applied in many industrial processes, and it is important for practical calcination/carbonation processes to have absorbents with high performance. The cyclic carbonation reactivity of the new absorbent was investigated by TGA (thermogravimetric analysis). The effects of the ratio of active material to binder in the new absorbent, the mechanics for preparation, and the reaction process of the high-reactivity CaO/Ca12Al14O33 absorbent have been analyzed. The results obtained here indicate that the new absorbent, CaO/Ca12Al14O33, has a significantly improved CO2 absorption capacity and cyclic reaction stability compared with other Ca-based CO2 absorbents. These results suggest that this new absorbent is promising in the ap...

Synthesis, experimental studies, and analysis of a new calcium-based carbon dioxide absorbent

Electro-thermal modeling and experimental validation for lithium ion battery

It is well-known that carbonation is characterized by a rapid initial rate followed by an abrupt transition to a very slow reaction rate. The slow period is believed to be controlled by the diffusion of reacting species throughout the product layer of CaCO3. The thickness of the carbonate layer formed on the free surfaces of CaO is a critical parameter to mark the end of the fast reaction period. This study addresses the question of how temperature affects the reaction process. For example, when the carbonation reaction enters the product layer diffusion-controlled stage at a low temperature such as 500 °C, how does an increase to 600 °C affect the conversion as a function of time and what changes occur in the CaCO3 product layer morphology? This work discusses the interesting finding that the fast reaction stage is recovered again when the temperature is increased. To understand and explain this phenomenon, it is necessary to investigate the mechanism of the temperature effect on the carbonation reaction...

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Effect of Temperature on the Carbonation Reaction of CaO with CO2

Mathematical models of multiple cycles for sorption-enhanced steam methane reforming and Ca-based sorbent regeneration in a fixed bed reactor are developed. Empirical correlations are used to describe steam methane reforming, the water−gas shift, and CO2 capture kinetics. The processes of multiple carbonation/calcination cycles of a Ca-based sorbent are taken into account to describe the sorption-enhanced hydrogen production process with the simultaneous removal of carbon dioxide by a Ca-based sorbent. The mathematical models are validated through comparing simulated results with experimental data. The model results qualitatively agree with experimental data. The effect of reactivity decay of dolomite, CaO/Ca12Al14O33, and limestone sorbents on sorption-enhanced hydrogen production and sorbent regeneration processes was studied through numerical simulation. The simulated results indicated that the operation time of producing high-purity hydrogen (that is defined as the time for the start of breakthrough, ...

Ningsheng Cai

Papers

Synthesis, experimental studies, and analysis of a new calcium-based carbon dioxide absorbent

Electro-thermal modeling and experimental validation for lithium ion battery

Effect of Temperature on the Carbonation Reaction of CaO with CO2

Modeling of Multiple Cycles for Sorption-Enhanced Steam Methane Reforming and Sorbent Regeneration in Fixed Bed Reactor

Performance and methane production characteristics of H2O–CO2 co-electrolysis in solid oxide electrolysis cells