CO2 Capture Research Articles

The Influence of Mg, Na, and Li Oxides on the CO2 Sorption Properties of Natural Zeolite

This study presents a comparative analysis of the CO2 sorption properties of natural zeolites sourced from the Tayzhuzgen (Tg) and Shankanay (Sh) deposits in Kazakhstan. The Tayzhuzgen zeolite was characterized by a Si/Al ratio of 5.6, suggesting partial dealumination, and demonstrated enhanced specific surface area following mechanical activation. Modification of the Tayzhuzgen zeolite with magnesium oxide significantly improved its CO2 sorption capacity, reaching 8.46 mmol CO2/g, attributed to the formation of the CaMg(Si2O6) phase and the resulting increase in basic active sites. TPD-CO2 analysis confirmed that MgO/Tg exhibited the highest basicity of the modified samples, further validating its potential for CO2 capture applications.

Assessing Best Practices in Natural Gas Production and Emerging CO2 Capture Techniques to Minimize the Carbon Footprint of Electricity Generation.

Natural gas (NG) is expected to provide a substantial portion of electricity generation in many jurisdictions for the foreseeable future. Postcombustion carbon capture and storage (CCS) effectively abates direct CO2 emissions; however, indirect NG supply chain emissions in most jurisdictions are incompatible with climate change mitigation goals. This life cycle assessment evaluates specific opportunities to reduce the carbon footprint of combined cycle gas turbine (CCGT) generation with CCS using existing low-emission NG production practices, technologies, and processes combined with emerging CCS techniques to achieve high CO2 capture rates and mitigate startup emissions. We find baseload life cycle greenhouse gas (GHG) emission intensity ranges from 22 to 62 kgCO2e/MWh for 95-98.5% CO2 capture, within the range of published estimates for wind and photovoltaic power and considerably below prior estimates of CCGT with CCS. Low-emission NG production practices reduce other environmental impacts, which are dominated by combustion-related air pollution. We also show how interim solvent storage can effectively mitigate emissions from CCGT start/stop cycles. This work highlights the importance of mitigating both CO2 and methane emissions from NG supply chains and proposes a more nuanced discussion regarding the potential contribution of NG to the future energy supply. A surrogate model is provided to estimate life cycle GHG emissions for CCGT with CCS and user-input parameters.

Efficient CO2 adsorption by deoiled flaxseed hydrochar.

This study optimizes CO2 adsorption using hydrochar from de-oiled flaxseed (FDOP), a waste byproduct of the oil extraction industry, through hydrothermal carbonization (HTC). The aim is to enhance CO2 capture sustainably and cost-effectively. Using Response Surface Methodology (RSM), in optimal conditions achieved 1153.26mg/g CO2 adsorption capacity under 215.15°C synthesis temperature, 3.05h synthesis time, 0.99M acid concentration, 8.997bar pressure, and 25.07°C adsorption temperature. Statistical analysis (F-value: 44.48, R²: 0.9705) confirmed strong model reliability. Kinetic analysis showed both physical and chemical adsorption, while thermodynamic analysis revealed exothermic behavior (ΔH° values: -46.697kJ/mol for M-225, -40.230kJ/mol for MA-203). After 10 regeneration cycles, the adsorption capacity was reduced by only 2.8% and 3.1%, indicating excellent recyclability. This study highlights FDOP-derived hydrochar as a highly efficient, low-cost adsorbent, offering industrial applications for carbon capture and waste management.

Application of UAVs and Remote Sensing Technologies for Atmospheric CO2 Capturing: A Study Application of UAVs and Remote Sensing in CO2 Reductions

Human activities are a significant contributor to climate change, with rising levels of CO₂ in the atmosphere. Several carbon capture and sequestration (CCS) methods have been developed to address this issue. Uncrewed Aerial Vehicles (UAVs) and remote sensing technologies are emerging as significant improvements to the efficiency and effectiveness of atmospheric carbon capture initiatives. This research examines using UAVs and remote sensing technologies to monitor, quantify, and manage atmospheric CO₂ levels. Furthermore, the study explores the implications of integrating robotic-drone technology, emphasizing their ability to contribute to a sustainable future. These technologies, incorporating modern data collection and analysis methodologies, provide promising answers for climate change mitigation and long-term environmental sustainability.

CO2 capture, geological storage, and mineralization using biobased biodegradable chelating agents and seawater.

Geological storage and mineralization of CO2 in mafic/ultramafic reservoirs faces challenges including limited effective porosity, permeability, and rock reactivity; difficulties in using seawater for CO2 capture; and uncontrolled carbonation. This study introduces a CO2 capture, storage, and mineralization approach with the utilization of biobased biodegradable chelating agents and seawater. An acidic chelating agent solution is used to increase effective porosity and permeability through enhanced mineral dissolution. For instance, applying an acidic N,N-Bis(carboxymethyl)-L-glutamate solution to a porous basalt increased effective porosity by 16% and permeability by 26-fold in 120 hours. Subsequently, alkaline chelating agent-containing seawater improves CO2 capture and storage by inhibiting mineralization, thus maintaining injectivity while providing ions for mineralization and further expanding storage space. Last, controlled mineralization is achieved by adjusting chelating agent biodegradation. Promising CO2 storage and mineralization capacities two orders higher than current techniques, this approach reduces required reservoir volume while enhancing efficiency.

Transforming carbon-intensive coal-fired power plants into negative emission technologies via biomass-fired calcium looping retrofit

Abstract Calcium looping is a promising CO2 capture technology due to reduced energy and economic penalties compared to mature solvent scrubbing technologies. It also can enable negative CO2 emissions when biomass is used to drive the sorbent regeneration process in the calciner. However, the trade-off between the energy, economic and environmental performance under different biomass co-firing fractions in the calciner and process operating scenarios has not yet been well understood. This study examined the potential for transforming a 580 MWel coal-fired power plant into a negative CO2 emitter via retrofit of calcium looping with biomass co-firing in the calciner. High-fidelity process models were developed in Aspen Plus and used to analyse the effect of biomass co-firing fraction, CO2 capture rate in the carbonator, and the fraction of flue gas fed to the carbonator on the techno-economic performance indicators. The results revealed that co-firing 30% biomass with coal in the calciner was sufficient for the retrofitted process to achieve negative CO2 emissions (−3.9 gCO2/kWelh). In this scenario, the levelized cost of electricity was 5% lower (81.1 €/MWelh) than that in the reference retrofit scenario without biomass co-firing (85.4 €/MWelh) at a carbon tax of 100 €/tCO2. Further improvement to the techno-economic performance was achieved by reducing the amount of CO2 captured in the carbonator by reducing either the CO2 capture rate (81.1 €/tCO2) or the amount of flue gas processed (80.4 €/tCO2). Although this was achieved at the expense of the increased specific CO2 emissions to 65.2 gCO2/kWelh and 109.0 gCO2/kWelh, respectively, the net specific emissions were still about 90% lower than those of the unabated host plant (792.3 gCO2/kWelh). This study demonstrated that depending on design priorities, biomass co-firing in the calciner can transform the existing coal-fired power plants into negative CO2 emission technologies or improve the process techno-economic viability.

Rubbery organic frameworks (ROFs) toward ultrapermeable CO2-selective membranes.

The capture of CO2 is of high interest in our society representing an essential tool to mitigate man-made climate warming. Membrane technology applied for CO2 capture offers several advantages in terms of energy savings, simple operation, and easy scale-up. Glassy membranes are associated with low gas permeability that negatively affect on their industrial implementation. Oppositely, rubbery membranes offer high permeability, but their selectivity is low. Here we report rubbery organic frameworks (ROFs) combining the high permeability of soft matrices with the high sieving selectivity of molecular frameworks. The best performing membranes provide a CO2/N2 selectivity up to 104 with a CO2 permeability up to 1000 Barrer, representing relevant performances for industrial implementation. Water vapors have a positive effect on CO2 permeability, and the CO2/N2 selectivity is higher than in dry conditions, as most of CO2 gas emissions are present in fully humidified gas streams. The synergetic high permeability/selectivity performances are superior to that observed with current state-of-the-art polymeric membranes.

Investigation of the performance of strontium oxide in carbonation–calcination looping for CO2 capture by the process simulation

Investigation of the performance of strontium oxide in carbonation–calcination looping for CO2 capture by the process simulation

A Comprehensive Review of Approaches in Carbon Capture, and Utilization to Reduce Greenhouse Gases

Addressing atmospheric CO2 levels is crucial for mitigating global warming and promoting sustainable fossil fuel use. This review explores various CO2 capture strategies, including pre-combustion, post-combustion, oxy-fuel combustion, direct air capture, chemical looping, and polymeric membranes. Each strategy is critically evaluated in terms of its advantages, limitations, and overall effectiveness. Additionally, this study discusses advanced separation techniques for captured CO2, emphasizing recent innovations in membrane technology integrated with cryogenic processes. This integration has the potential to economically extract CO2 from diverse industrial processes, offering significant benefits in terms of operational cost reduction and increased efficiency. A detailed market analysis is also presented to explore feasible CO2 utilization options, highlighting potential incentives and motivations for capturing CO2. Furthermore, the technological readiness level of various capture and separation techniques is assessed, offering insights into their development and progress over time. This comprehensive analysis aims to support the advancement of effective and economically viable CO2 management solutions, contributing to a more sustainable and climate-resilient future.

Accelerated weathering of construction‐grade limestone for CO2 absorption

AbstractAccelerated weathering of limestone (AWL) process efficiently captures CO2 from point source emissions. However, despite achieving an outstanding capture efficiency of 73.51 %, lab‐grade (LG) limestone with 99.90 % CaCO3 as an absorbent is costly ($2757.70/t), making commercialization of AWL impractical. This work delves into the viability of utilizing construction‐grade (CG) limestone (93.26% purity) for the AWL process facilitated by potable water in an absorption tower for post‐combustion capture. The result shows that CG limestone achieves comparable CO2 capture efficiency of 8.0–74.68% and bicarbonate (Ca(HCO3)2) concentration of 0.63–3.10 mM compared with LG limestone. However, LG limestone has 0.29 mol CO2/mol CaCO3 higher CO2 absorption capacity and a faster absorption rate than CG limestone, indicating a somewhat better CO2 capture performance. Nevertheless, CG limestone offered a more cost‐effective alternative, with a $2735.24 lower cost per ton of CaCO3 and a $2651.63 per ton CO2 lower CO2 capturing cost at the highest carbon capture efficiency (HCCE) condition compared to LG limestone. The kinetic analysis shows that the forward reactions in the AWL process are significantly faster at elevated CO2 concentration, with the mass transfer coefficient affirming that CO2 dissolves faster than CaCO3, in line with prior research. Thus, this work validates that CG limestone‐based AWL achieves comparable CO2 capture performance to that of LG limestone, offering a cost‐efficient alternative. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Simplified mathematical model of oxy-fuel combustion of municipal solid waste in the grate furnace: effect of different flue gas recirculation rates and comparison with conventional mode

Bioenergy carbon capture technology (BioCCS or BECCS) plays a key role in the European Green Deal, which aims to decarbonize industry and energy sectors, resulting in the production of energy with negative CO2 emissions. Due to the biogenic origin of carbon contained in municipal solid waste (MSW), the application of carbon capture in waste incinera-tion plants can be classified as BioCCS. Thus, this technology has attracted scientists' attention recently since it reduces excessive waste and emissions of carbon dioxide. Currently, there are four incineration plants in the Netherlands, Norway and Japan, in which CO2 capture is implemented; however, they are based on the post-combustion technique since it is the most mature method and not requires many changes in the system. Nevertheless, the separation of CO2 from the flue gas flow, which contains mostly nitrogen, is complex and causes a large drop in the total performance of the system. Oxy-fuel combustion technology involves the replacement of air as an oxidizer into high purity oxygen and recirculated exhaust gas. As a result, CO2-rich gas is produced that is practically ready for capture. The main goal of the study is to develop a math-ematical model of oxy-waste combustion to answer the research questions, such as how the composition of oxidant that is supplied to the process affects the combustion performance. The model includes all important processes taking place within the chamber, such as pyrolysis, char burnout and gas combustion over the grate. The results of the work will contribute to the development of oxy-waste incineration plants and will be useful for design purposes.

Carbon dioxide capture in large-scale CCGT power plant from flue gases obtained from various fuel mixtures

In this study, the thermodynamic analysis of a combined cycle gas turbine integrated with post-combustion carbon capture and storage using the solvent method is performed. The syngas obtained from the gasification of sewage sludge is mixed with methane and nitrogen-rich natural gas fuels at different proportions, used in the gas turbine, and the properties of fuel and flue gases are analyzed. The flue gas obtained from the fuel mixture is passed through the post-combustion carbon capture and storage at various load conditions to assess the heat and electricity required for the carbon capture process. The solvent used for the carbon capture from flue gases enables CO2 capture with the high efficiency of 90%. With the calculated results, the load conditions of flue gas using fuel mixtures are identified, which reduces the heat and power demand of post-combustion carbon capture and storage and provides the possibility to achieve neutral emission. The impact of selected operating conditions of post-combustion carbon capture and storage on the CO2 emission reduction process and on the power plant performances is investigated. Considering the factors of electricity generation, energy efficiency, heat supply to the consumers, operating load of post-combustion carbon cap-ture and storage and CO2 emission, the 50% mixture of syngas with both fuels performs better. Also, the use of a mixture of 2-amino-2methyl-1-propanol and piperazine with reboiler duty 3.7 MJ/kgCO2 in post-combustion carbon capture and storage slightly enhanced the performance of the power plant compared to the use of monoethanolamine with reboiler duty 3.8 MJ/kgCO2.

Optimizing energy consumption in post-combustion CO2 capture at an NGCC power plant: a simulation-based approach

Abstract This study aims to optimize energy consumption in post-combustion carbon capture processes at a Natural Gas Combined Cycle (NGCC) power plant. It further addresses challenges associated with steam extraction from NGCC power plants and explores non-condensable steam turbines to boost process efficiency. Various scenarios are explored to minimize energy requirements by leveraging heat integration and alternative solvent compositions. The research uses simulations with commercially available software and literature-derived data to address the challenges of high energy consumption in such processes. Emphasis is placed on optimizing solvent composition and implementing advanced heat optimization strategies to reduce energy consumption. Four scenarios with different solvent compositions are investigated, utilizing Monoethanolamine and aqueous piperazine. The results show that process parameter optimization and heat optimization strategies can result in significant energy savings. To attain a carbon-neutral energy landscape, this research helps develop more sustainable and effective carbon capture methods.

Collective molecular-scale carbonation path in aqueous solutions with sufficient structural sampling: From CO2 to CaCO3.

The carbonation reaction is essential in the global carbon cycle and in the carbon dioxide (CO2) capture. In oceans (pH 8.1) or in synthetic materials such as cement or geopolymers (pH over 12), the basic pH conditions affect the reaction rate of carbonation. However, the precipitation of calcium or magnesium carbonates acidifies the environment and, therefore, limits further CO2 capture. Here, we investigate how pH influences carbonation pathways in neutral and basic solutions at the atomic scale using reactive molecular simulations coupled with enhanced sampling methods from CO2 to calcium carbonate (CaCO3). Two distinct CO2 conversion pathways are identified: (1) CO2 hydration: CO2+H2O⇌H2CO3⇌HCO3-+H+⇌CO32-+2H+ and (2) CO2 hydroxylation: CO2+OH-⇌HCO3-⇌CO32-+H+. The CO2 hydration pathway occurs in both neutral and basic aqueous solutions, but reactions differ significantly between the two pH conditions. The formation of the CO32- is characterized by a markedly high free energy barrier in the neutral solution. The CO2 hydroxylation pathway is only found in basic solutions. Notably, the CO2 molecule exhibits a pronounced energetic preference for reacting with hydroxide ions (OH-) rather than with water molecules, resulting in significantly reduced free energy barriers along the CO2 hydroxylation pathway. The reaction rate estimation suggests that the CO2 hydroxylation path is the most favorable carbonation pathway in the basic solution. Once the CO32- anion is formed in the presence of alkali-earth (e.g., Ca2+ and Mg2+) cations, carbonate formation can proceed.

Iron Impurity Impairs the CO2 Capture Performance of MgO: Insights from Microscopy and Machine Learning Molecular Dynamics.

Magnesium oxide (MgO) is a promising sorbent for direct air capture (DAC) of carbon dioxide. Iron (Fe) is a common impurity in naturally occurring MgO and minerals used to produce MgO, yet a molecular-scale understanding of Fe-doping effects on carbonation is lacking. Here, we observed reduced carbonation performance in Fe-doped MgO experimentally. The energetics of adsorbing a (bi)carbonate ion on pristine and Fe-doped MgO(001) surfaces were further investigated using ab initio and machine learning potential molecular dynamics coupled with metadynamics simulations. Both pristine and Fe-doped surfaces exhibited a basic (OH-) hydration layer, where the (bi)carbonate ion adsorption is thermodynamically favorable. However, the dissolution of surface Fe had smaller energy barriers and was more favorable than Mg. Leached Fe likely neutralized the near-surface basicity, yielding reduced reactivity on Fe-doped MgO. Our observations offer critical insights for material selection and emphasize the importance of evaluating the geologic origin of earth materials used for DAC.

Enhancing efficiency and economic viability in Rectisol system with cryogenic liquid expander

AbstractCryogenic liquid expanders have emerged as a potential energy‐saving alternative to Joule–Thomson (JT) valves in cryogenic processes. The potential impact of incorporating a liquid expander into the Rectisol process has not been quantitatively evaluated. This study seeks to assess the effectiveness of replacing the JT valve with a liquid expander in the Rectisol process through the development of thermodynamic models for each component and conducting simulations using the ASPEN software. Additional analyses, including energy, CO2 footprint, exergy, and economic evaluations, are performed for the Rectisol system. Utilizing an expander has been shown to lower energy usage by 2.52% and boost CO2 capture by 5.55%, resulting in a 7.65% decrease in energy expenditure per unit CO2 and a 1.29% rise in total exergy efficiency. Lower expander outlet temperatures and the green power output generated by the expander are the main reasons for these benefits, and the CO2 footprint analysis explains how they work. The application of an expander in the Rectisol process is an economical and low‐risk solution; the payback period is 0.32 years, and the lifetime profit is 53 folds of the investment.

Oxidative degradation of glycine in aqueous KOH/K2CO3 solutions for CO2 capture

AbstractPotassium hydroxide and potassium carbonate, being cost‐effective and environmentally friendly CO2 capture solvents, are promising candidates for carbon capture applications. Their slow absorption kinetics, however, necessitate strategies to enhance their rates, thereby reducing the capital costs of absorption equipment and saving energy for regenerating large volumes of solvent. Glycine, a potential additive, is explored for this purpose. While glycine‐based solvents are more stable than MEA, their amino functional group renders them susceptible to oxidative degradation. This study investigates the degradation of these solvents and the influence of potassium hydroxide and potassium carbonate on their stability. The experiment was performed under 100% O2 at 90 °C and 3 bar for about 3 weeks. It was observed that glycinate degraded by 53% for the glycinate‐only solution. The results also show that the addition of potassium hydroxide and potassium carbonate to a glycinate‐only solution had a mixed effect on the degradation of glycinate. Potassium hydroxide increased degradation by 5% compared to the glycinate‐only solution, while potassium carbonate decreased degradation by 4%. This order is supported by the degradation rate constants. Meanwhile, under N2, no significant change was observed in glycine concentration. Glycine's susceptibility to oxidative degradation is likely attributed to its less compact and rigid structure, resulting in weaker bonding and increased vulnerability to external factors. This instability leads to the formation of formate, carbonate, acetate, and oxalate as the primary degradation products across all studied solutions. A proposed mechanism for glycinate oxidative degradation sheds light on this process. These findings are crucial for informed decision making regarding performance trade‐offs in point source carbon capture and direct air capture, where oxygen is a prevalent gas component and potassium‐based solutions are commonly employed as absorbents. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Comparison of Adsorption Capacity of Amine Modified Activated Carbon from Stone Apple for CO2 Capture

Comparison of Adsorption Capacity of Amine Modified Activated Carbon from Stone Apple for CO2 Capture

Fossil Fuel Prospects in the Energy of the Future (Energy 5.0): A Review

Achieving the energy and climate goals of sustainable development, declared by the UN as imperative and relevant for the upcoming Society 5.0 with its human-centricity of technological development, requires ensuring a “seamless” Fourth Energy Transition, preserving but at the same time modifying the role of fossil fuels in economic development. In this regard, the purpose of this review is to analyze the structure of publications in the field of technological platforms for the energy of the future (Energy 5.0), with digital human-centric modernization and investment in fossil fuel extraction in the context of the Fourth Energy Transition. To achieve this goal, this review presents a comprehensive overview of research in the field of determining the prospects of fossil fuels within Energy 5.0, characterized not only by the dominance of renewable energy sources and the imperative of zero CO2 emissions, but also by the introduction of human-centric technologies of Industry 5.0 (the Industrial Internet of Everything, collaborative artificial intelligence, digital triplets). It was concluded that further research in such areas of Energy 5.0 development as the human-centric vector of modernization of fossil fuel extraction and investment, achieving energy and climate goals for sustainable development, reducing CO2 emissions in the mineral extractive sector itself, and developing CO2 capture and utilization technologies is important and promising for a “seamless” Fourth Energy Transition.

Enhanced carbon dioxide capture through composite of polyamide 6 nanofibers and zeolites: Preparation and performance evaluation

The increasing concentration of atmospheric carbon dioxide (CO2) demands innovative solutions for its capture and sequestration. Composite and nanocomposite materials have gained attention for their high surface area, adjustable properties, and improved adsorption capabilities. This manuscript explores the preparation, characterization, and performance assessment of a novel composite material consisting of polyamide 6 nanofibers combined with two types of zeolites, designed for CO2 capture. We detail the fabrication process, as well as the structural, chemical, and morphological characterization of the composites. The results confirmed the successful modification of polyamide 6 nanofibers with both types of zeolites. CO2 sorption measurements revealed that the composite with zeolite Y exhibited a notably high sorption capacity, with a maximum of 35.8 cm³/g, significantly surpassing the performance of amine-modified nanofibers, which demonstrated sorption capacities approximately three times lower. These findings highlight the potential of this composite for efficient CO2 capture, providing valuable insights into its practical application for reducing greenhouse gas emissions. While the CO2 sorption capacities of the composite are lower than those of pure zeolites, the composite offers practical advantages, such as easier handling and simplified application.