Global warming and climate change concerns have triggered global efforts to reduce the concentration of atmospheric carbon dioxide (CO2). Carbon dioxide capture and storage (CCS) is considered a crucial strategy for meeting CO2 emission reduction targets. In this paper, various aspects of CCS are reviewed and discussed including the state of the art technologies for CO2 capture, separation, transport, storage, leakage, monitoring, and life cycle analysis. The selection of specific CO2 capture technology heavily depends on the type of CO2 generating plant and fuel used. Among those CO2 separation processes, absorption is the most mature and commonly adopted due to its higher efficiency and lower cost. Pipeline is considered to be the most viable solution for large volume of CO2 transport. Among those geological formations for CO2 storage, enhanced oil recovery is mature and has been practiced for many years but its economical viability for anthropogenic sources needs to be demonstrated. There are growing interests in CO2 storage in saline aquifers due to their enormous potential storage capacity and several projects are in the pipeline for demonstration of its viability. There are multiple hurdles to CCS deployment including the absence of a clear business case for CCS investment and the absence of robust economic incentives to support the additional high capital and operating costs of the whole CCS process.

https://www.elsevier.com/__data/assets/pdf_file/0005/96980/Current-status-carbon-capture.pdf

An overview of current status of carbon dioxide capture and storage technologies

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

Chemical-looping combustion (CLC) for inherent CO2 separations—a review

Deactivation of hydroprocessing catalysts

Redox catalysis, including photocatalysis and (photo)electrocatalysis, may alleviate global warming and energy crises by removing excess CO2 from the atmosphere and converting it to value-added resources. Nano-to-atomic two-dimensional (2D) materials, clusters and single atoms are superior catalysts because of their engineerable ultrathin/small dimensions and large surface areas and have attracted worldwide research interest. Given the current gap between research and applications in CO2 reduction, our review systematically and constructively discusses nano-to-atomic surface strategies for catalysts reported to date. This work is expected to drive and benefit future research to rationally design surface strategies with multi-parameter synergistic impacts on the selectivity, activity and stability of next-generation CO2 reduction catalysts, thus opening new avenues for sustainable solutions to climate change, energy and environmental issues, and the potential industrial economy.

Surface strategies for catalytic CO2 reduction: from two-dimensional materials to nanoclusters to single atoms

A concept for combined hydrogen and power production from natural gas with CO2 capture is presented. The process involves the use of a metal oxide in fluidized bed reactors; the metal oxide is reduced by a mixture of natural gas and steam in a fuel reactor and oxidized by air in the air reactor. The natural gas is partially oxidized in the fuel reactor, resulting in a mixture of CO2, H2, H2O, and CO from the exit. If no hydrocarbons are present in this stream, it can be sent to a water gas shift reactor to get an undiluted stream of CO2 and H2. The product stream from the air reactor contains mostly N2 and some unreacted oxygen. The oxidation reaction is exothermic with resulting heat production in the air reactor; this heat is used to maintain the oxygen carrier particles at the high temperature necessary for the endothermic reaction in the fuel reactor. The hot gases from the air reactor could be used for power production. Metal oxides of Ni, Cu, Mn, and Fe were prepared by impregnation on a SiO2 suppor...

Integrated hydrogen and power production with CO2 capture using chemical-looping reforming-redox reactivity of particles of CuO, Mn 2O3, NiO, and Fe2O3 using SiO 2 as a support

Chemical-looping combustion (CLC) and chemical-looping reforming (CLR) involve the use of a metal oxide as an oxygen carrier which transfers oxygen from combustion air to the fuel. Two interconnected fluidized beds, a fuel reactor, and an air reactor are used in both processes. In the fuel reactor, the fuel is oxidized by a metal oxide, and in the air reactor, the reduced metal is oxidized back to the original phase. In CLC, a high conversion of the fuel to CO2 and H2O is required in the fuel reactor, whereas only a partial oxidation of the fuel is desired in CLR. Oxides of Ni, Cu, Fe, and Mn supported on SiO2 and MgAl2O4 were prepared by dry impregnation and investigated under alternating reducing and oxidizing conditions in a thermogravimetric analyzer at 800−1000 °C using fuel (10% CH4, 10% H2O, and 5% CO2) and oxidizing gas (5% O2). NiO and CuO supported on both SiO2 and MgAl2O4 showed very high reactivity. However, the reactivity of NiO/SiO2 decreased as a function of the cycle number at 950 °C but w...

Redox investigation of some oxides of transition state metals Ni, Cu, Fe and Mn supported on SiO2 and MgAl2O4,

Reduction and oxidation kinetics of Mn3O4/Mg–ZrO2 oxygen carrier particles for chemical-looping combustion

Fischer-Tropsch synthesis (FTS) at 20 bar. and 483 K, with H-2-poor syngas (H-2/CO ratio = 1.0) in order to simulate gasified biomass, was performed over Al2O3-supported catalysts with various ratios of Fe:Co (12 wt% bimetal) prepared by co-impregnation. Co was found to be incorporated into the Fe2O3 phase after calcination, at least for the iron-rich samples, while no evidence of Fe incorporated into Co3O4 was found. Upon reduction, most probably FeCo alloys were formed in the iron-rich bimetallic samples. The degree of reduction of the catalysts showed a non-linear behavior with respect to the Fe:Co ratio, but it is obvious that Co increases the reducibility of Fe. Alloying Co with small/moderate amounts of Fe improved the FT activity compared to the 100% Co catalyst at low conversion levels. Alloying Fe with small/moderate amounts of Co lowered the FT activity, but increased the relative water-gas-shift (WGS) activity compared to the 100% Fe catalyst. However, the overall WGS activity was very low for all catalysts, even with external water addition to the feed, resulting in low FT productivities (per gram catalyst) due to the low partial pressure of H-2. A higher Fe:Co ratio in the bimetallic catalyst generally resulted in higher relative WGS activity, but did not lower the H-2/CO usage ratio to the desired value of 1.0. For the Fe-containing catalysts, the space-time yield of hydrocarbons (HCs) decreased with increasing partial pressure of water or reduced space velocity, indicating an inhibition of water on the FT activity, most often resulting in low FT productivity under the conditions with highest relative WGS activity (usage ratios closest to the inlet H-2/CO ratio). Moreover, the co-impregnation technique resulted in a surface enrichment of Fe, at least for the Co-rich samples, covering the Co sites. For the bimetallic catalysts, both FT and WGS activities rapidly declined at high partial pressure of water due to deactivation by oxidation and sintering. However, the results indicate that WGS and FT proceeded over sites of different nature in the bimetallic catalysts. The bimetallic catalysts showed essentially no synergy effects with respect to HC selectivities and olefin/paraffin ratios, which partly can be explained by the use of a sub-stoichiometric H-2/CO ratio as feed. The higher the Fe content, the lower were the C5+ selectivity and C-3 olefin/paraffin ratio. Water addition increased the C5+ selectivity and C-3 Olefin/paraffin ratio and reduced the CH4 selectivity.

Hydrocarbon production via Fischer-Tropsch synthesis from H-2-poor syngas over different Fe-Co/gamma-Al2O3 bimetallic catalysts

The kinetics of reduction and oxidation of Ni based oxygen carrier particles with CH4 and O2 have been investigated. The kinetic parameters were obtained from reactivity data using a thermogravimetric analyzer (TGA), where the freeze-granulated particles were tested using different reactant gas concentrations, temperatures, and particles sizes. The particles showed high reactivity during both reduction and oxidation at temperatures above 900 °C. The shrinking-core model for spherical grain geometry of the reacting particle with chemical reaction control was used to determine the kinetic parameters during both the reduction and oxidation reactions. The reaction order found was 0.4 and 1 for CH4 and O2, respectively, while the activation energies found were 114 and 40 kJ/mol for reduction and oxidation reactions, respectively. The reactivity data and kinetic parameters were used to estimate the solid inventory needed in a chemical-looping combustion (CLC) system. The total solid inventory varies with the so...

/pdf/reaction-kinetics-of-freeze-granulated-nio-mgal2o4-oxygen-2e52q19kbj.pdf

Börje Sten Gevert

Papers

Integrated hydrogen and power production with CO2 capture using chemical-looping reforming-redox reactivity of particles of CuO, Mn 2O3, NiO, and Fe2O3 using SiO 2 as a support

Redox investigation of some oxides of transition state metals Ni, Cu, Fe and Mn supported on SiO2 and MgAl2O4,

Reduction and oxidation kinetics of Mn3O4/Mg–ZrO2 oxygen carrier particles for chemical-looping combustion

Hydrocarbon production via Fischer-Tropsch synthesis from H-2-poor syngas over different Fe-Co/gamma-Al2O3 bimetallic catalysts

Reaction Kinetics of Freeze-Granulated NiO/MgAl2O4 Oxygen Carrier Particles for Chemical-Looping Combustion