There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

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

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

Structure and nanostructure in ionic liquids.

Ionic liquids offer a unique suite of properties that make them important candidates for a number of energy related applications. Cation–anion combinations that exhibit low volatility coupled with high electrochemical and thermal stability, as well as ionic conductivity, create the possibility of designing ideal electrolytes for batteries, super-capacitors, actuators, dye sensitised solar cells and thermo-electrochemical cells. In the field of water splitting to produce hydrogen they have been used to synthesize some of the best performing water oxidation catalysts and some members of the protic ionic liquid family co-catalyse an unusual, very high energy efficiency water oxidation process. As fuel cell electrolytes, the high proton conductivity of some of the protic ionic liquid family offers the potential of fuel cells operating in the optimum temperature region above 100 °C. Beyond electrochemical applications, the low vapour pressure of these liquids, along with their ability to offer tuneable functionality, also makes them ideal as CO2 absorbents for post-combustion CO2 capture. Similarly, the tuneable phase properties of the many members of this large family of salts are also allowing the creation of phase-change thermal energy storage materials having melting points tuned to the application. This perspective article provides an overview of these developing energy related applications of ionic liquids and offers some thoughts on the emerging challenges and opportunities.

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Energy applications of ionic liquids

An investigation Was carried out of oxidative esterification of aldehydes with alcohols and oxygen to corresponding esters over Pb, Mg-doped Al2O3-supported Pd catalyst. This catalyst was prepared by impregnating method and characterized by X-ray diffraction, differential scanning calorimetry, X-ray photoelectron spectroscopy, and transmission electron microscopy. The results showed that Pd atoms with Pb atoms formed bimetallic Pd3Pb crystals, and Mg existed on the support as MgO with election effect oil Pd3Pb crystals. The reactions of aldehyde with alcohol in the presence and absence of oxygen over the doped and undoped Pd catalysts were examined to evaluate the effects of Pb and Mg. It was found that the doping agents Mg had positive effect on reaction rate acceleration only in the presence of oxygen, Pb or the collaboration of Pb and Mg had positive effect on reaction rate acceleration and selectivity enhancement in the presence of oxygen or not. (C) 2009 Elsevier B.V. All rights reserved.

Effects of Pb and Mg doping in Al2O3-supported Pd catalyst on direct oxidative esterification of aldehydes with alcohols to esters

Solubility of CO2 in aqueous mixtures of monoethanolamine and dicyanamide-based ionic liquids

Direct coal liquefaction residue (DCLR) contains about 25% asphaltenes which are proved to be important precursors for preparing high value-added carbon materials. In this work, ionic liquids (ILs) were used as potential solvents to extract asphaltenes from DCLR, and a series of dialkylphosphate ILs, i.e., imidazolium-based, pyridinium-based, and ammonium-based, were synthesized and used to extract asphaltenes from DCLR. The influences of extractive time, extractive temperature, and mass ratio of ILs to DCLR on extraction efficiency of asphaltenes were investigated and the optimized conditions were determined. In order to understand the mechanism of extraction asphaltenes with ILs, the extracts were characterized by elemental analysis, FT-IR, 13CNMR, and so on. The results show that it is feasible to extract asphaltenes from DCLR with dialkylphosphate ILs. The structure and size of anion and cation of ILs probably are the main factors that influence the extraction yield and the physicochemical characteris...

Study on Extraction Asphaltenes from Direct Coal Liquefaction Residue with Ionic Liquids

Protic ionic liquids extract asphaltenes from direct coal liquefaction residue at room temperature

The deficiency of mass-transfer properties in ionic liquids (ILs) has become a bottleneck in developing the novel IL-based CO2 capture processes. In this study, the liquid-side mass-transfer coefficients (k(L)) were measured systematically in a stirred cell reactor by the decreasing pressure method at temperatures ranging from 303 to 323 K and over a wide range of IL concentrations from 0 to 100 wt %. Based on the data of kL, the kinetics of chemical absorption of CO2 with mixed solvents containing 30 wt % monoethanolamine (MEA) and 0-70 wt % ILs were investigated. The k(L) in IL systems is influenced not only by the viscosity but also the molecular structures of ILs. The enhancement factors and the reaction activation energy were quantified. Considering both the mass-transfer rates and the stability of IL in CO2 absorption system, the new IL-based system MEA + [bmim][NO3] + H2O is recommended. (C) 2014 American Institute of Chemical Engineers

Haifeng Dong

Papers

Effects of Pb and Mg doping in Al2O3-supported Pd catalyst on direct oxidative esterification of aldehydes with alcohols to esters

Solubility of CO2 in aqueous mixtures of monoethanolamine and dicyanamide-based ionic liquids

Study on Extraction Asphaltenes from Direct Coal Liquefaction Residue with Ionic Liquids

Protic ionic liquids extract asphaltenes from direct coal liquefaction residue at room temperature

Gas-Liquid Mass-Transfer Properties in CO2 Absorption System with Ionic Liquids