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

Cyclic organic carbonates represent a relevant class of chemicals that can be prepared from CO2 by cycloaddition to epoxides. The application of efficient catalysts is crucial in allowing the cycloaddition reaction to proceed under very mild conditions of temperature, pressure, and CO2 concentration, thus resulting in a sustainable and carbon-balanced approach to CO2 conversion. This is particularly the case if impure waste CO2 could be employed as a feedstock. In this Review, we have critically analyzed the burgeoning literature on the cycloaddition of CO2 to epoxides with the aim to provide state-of-the-art knowledge on the catalysts that can convert CO2 to carbonates under ambient conditions. These have been systematically organized in families of compounds and critically scrutinized in terms of catalytic activity, availability and mechanistic features. Finally, we provide an overview on the catalytic systems able to function using diluted and impure CO2 as a feedstock.

Catalytic Strategies for the Cycloaddition of Pure, Diluted, and Waste CO2 to Epoxides under Ambient Conditions

Dramatically increased CO2 concentration from several point sources is perceived to cause severe greenhouse effect towards the serious ongoing global warming with associated climate destabilization, inducing undesirable natural calamities, melting of glaciers, and extreme weather patterns. CO2 capture and utilization (CCU) has received tremendous attention due to its significant role in intensifying global warming. Considering the lack of a timely review on the state-of-the-art progress of promising CCU techniques, developing an appropriate and prompt summary of such advanced techniques with a comprehensive understanding is necessary. Thus, it is imperative to provide a timely review, given the fast growth of sophisticated CO2 capture and utilization materials and their implementation. In this work, we critically summarized and comprehensively reviewed the characteristics and performance of both liquid and solid CO2 adsorbents with possible schemes for the improvement of their CO2 capture ability and advances in CO2 utilization. Their industrial applications in pre- and post-combustion CO2 capture as well as utilization were systematically discussed and compared. With our great effort, this review would be of significant importance for academic researchers for obtaining an overall understanding of the current developments and future trends of CCU. This work is bound to benefit researchers in fields relating to CCU and facilitate the progress of significant breakthroughs in both fundamental research and commercial applications to deliver perspective views for future scientific and industrial advances in CCU.

Industrial carbon dioxide capture and utilization: state of the art and future challenges

Pd/ZnO catalysts for direct CO2 hydrogenation to methanol

Carbon dioxide (CO2) is the major contributor to greenhouse gas (GHG) emissions and the main driver of climate change. Currently, CO2 utilization is increasingly attracting interest in processes like enhanced oil recovery and coal bed methane and it has the potential to be used in hydraulic fracturing processes, among others. In this review, the latest developments in CO2 capture, utilization, conversion, and sequestration are examined through a multi-scale perspective. The diverse range of CO2 utilization applications, including mineralization, biological utilization, food and beverages, energy storage media, and chemicals, is comprehensively presented. We also discuss the worldwide research and development of CO2 utilization projects. Lastly, we examine the key challenges and issues that must be faced for pilot-scale and industrial applications in the future. This study demonstrates that CO2 utilization can be a driver for the future development of carbon capture and utilization technologies. However, considering the amount of CO2 produced globally, even if it can be reduced in the near-to mid-term future, carbon capture and storage will remain the primary strategy and, so, complementary strategies are desirable. Currently, the main CO2 utilization industry is enhanced oil and gas recovery, but considering the carbon life cycle, these processes still add CO2 to the atmosphere. In order to implement other CO2 utilization technologies at a large scale, in addition to their current technical feasibility, their economic and societal viability is critical. Therefore, future efforts should be directed toward reduction of energy penalties and costs, and the introduction of policies and regulation encouraging carbon capture, utilization and storage, and increasing the public acceptance of the strategies in a complementary manner.

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Recent advances in carbon dioxide utilization

Flexible operation of the switchable chlor-alkali process is a novel strategy for minimizing electricity costs in markets with volatile prices (Bree et al. ( 2018 )). This strategy allows for adjusting the process to electricity price profiles, by varying the production rate and by switching the operation between two different modes: the H2 mode and O2 mode. The size of the electrolyzer is a crucial factor because oversizing on the one hand leads to higher operational flexibility but on the other hand to increased capital costs. Here, we combine the optimization of the operation and electrolyzer size in the switchable chloralkali process for given electricity price profiles. To arrive at the optimum in reasonable computation time, we use a piecewise linear approximation and decomposition method employing the golden-section search. We verify that electrolyzer oversizing in the switch-able chlor-alkali process is a suitable strategy for reducing the total production cost when the specific capital costs of the oversizing are low enough and the electricity price strongly fluctuates.

Optimal Oversizing and Operation of the Switchable Chlor-Alkali Electrolyzer for Demand Side Management

IGCC (Integrated Gasification Combined Cycle) power plant is one of the promising power generation systems for the future as it can utilize the plentiful resource of coal in an eco-friendly way. The IGCC system is more complicated than the conventional pulverized coal power plant, so its dynamics should be investigated and an appropriate control strategy must be devised to ensure stable and efficient operation. In this research, Elevated Pressure Air Separation Unit (EP ASU) in an IGCC power plant is studied from the viewpoint of dynamic systems analysis. EP ASU separates cryogenic air feed into oxygen and nitrogen in a high pressure column and sends them to the gasification unit and gas turbine. Equation-based modeling of the cryogenic rectification column in EP ASU has been carried out using the software platform of gPROMS. Also, the transient behavior in response to various disturbances is studied through the dynamic simulation. Based on dynamic analysis, a control strategy is suggested at the end.

http://ieeexplore.ieee.org/iel5/6375948/6393028/06393056.pdf

Dynamic modeling and control studies for the Elevated Pressure Air Separation Unit in an IGCC power plant

The air separation unit (ASU) is one of the core elements of integrated gasification combined cycle (IGCC) power plants. The ASU separates air into pure oxygen and nitrogen, to be sent to the gasifier and the gas turbine, respectively. This system consumes about 10% of the gross power output generated in IGCC, so its economical operation is important for lowering the overall power generation cost. The use of an elevated-pressure air separation unit (EP ASU), in which the operating pressure is higher than in a conventional ASU, is known to lead to significant energy savings. In this research, controlled variable selection for an EP ASU was studied, considering both the controllability and economics, that is, with the objective of maintaining economically near-optimal operations in the presence of anticipated load changes. The main tool used for this was the so-called “minimum singular value rule” within the overall framework of self-optimizing control (SOC). For the purpose of selecting and testing self-op...

Control Structure Selection for the Elevated-Pressure Air Separation Unit in an IGCC Power Plant: Self-Optimizing Control Structure for Economical Operation

Kosan Roh

Papers

Optimal Oversizing and Operation of the Switchable Chlor-Alkali Electrolyzer for Demand Side Management

Dynamic modeling and control studies for the Elevated Pressure Air Separation Unit in an IGCC power plant

Control Structure Selection for the Elevated-Pressure Air Separation Unit in an IGCC Power Plant: Self-Optimizing Control Structure for Economical Operation

Design and Sustainability Analysis of a Combined CO2 Mineralization and Desalination Process

Design of 24/7 continuous hydrogen production system employing the solar-powered thermochemical S–I cycle