Carbon Capture Technologies Research Articles

Incentive policies to realize large-scale deployment of CCS in China's power sector and its economy-wide impacts

Given the carbon capture and storage (CCS) technology is still in the demonstration phase, large-scale deployment of CCS is urgently needed in the coming decades, especially in the power sector. Therefore, we built a computable general equilibrium model with detailed electricity technology module and assessed the economy-wide impacts of multiple incentive policies on large-scale deployment of CCS in the power sector. Results show that, first, if only CCS is subsidized, without supplementing carbon pricing, it will lead to deviations from the core environmental objectives of CCS development. Secondly, when CCS subsidies are combined with carbon pricing, if the sectoral indirect tax is reduced, the GDP loss can be better alleviated, and it can also have an obvious positive impact on energy conservation and emission reduction. Finally, a gradual sector-coverage way of carbon pricing contributes to further mitigating the accumulated GDP loss, easing sectoral profit losses, and improving positive effects on energy indicators.

Evaluation of carbon capture technologies in the oil and gas industry using a socio-technical systems perspective-based decision support system under interval type-2 trapezoidal fuzzy set

Concerns in relation to consequences of global warming and climate change have activated worldwide attempts for mitigating the concentration of carbon dioxide (CO2) produced by the industrial sector. Decarbonizing the oil and gas refining (OGR) industries is a challenging problem for policy-makers owing to its potential to prevent economic, environmental, and health risks. In this regard, CO2 capture, utilization, and storage (CCUS) technologies are the most encouraging options to decarbonize. The technologies related to the part of CO2 capture can play a vital role in solving the mentioned problem. Various technologies have been employed for CO2 capture, and choosing the appropriate technology is a complex multi-criteria decision-making (MCDM) issue. This work develops a novel and robust decision support system (DSS). The DSS integrates MCDM techniques of the Delphi and Entropy integration method (DAEIM) and complex proportional assessment of alternatives (COPRAS) method with the interval type-2 trapezoidal fuzzy (IT2TF) environment. The proposed DSS is used to evaluate, prioritize, and choose technologies for CO2 capture. A hybrid criteria system, which involves elements of socio-technical systems perspective has been used for evaluating the candidate technologies. For implementing the DSS of this work, five capture technologies of post-combustion (A_cc1), pre-combustion (A_cc2), oxy-fuel combustion (A_cc3), direct air capture (A_cc4), and indirect air capture (A_cc5) have been chosen for evaluation. The final value of each technology is A_cc1 (0. 2907), A_cc2 (0.2602), A_cc3 (0.1005), A_cc4 (0.2304), and A_cc5 (0.1181) and the preferences of the technologies are A_cc1> A_cc2> A_cc4> A_cc5> A_cc3. The evaluation findings reveal that post-combustion technology with the value of 0.2907 is the most suitable scenario for the capture of CO2 emissions from Iran's OGR systems. The computation results demonstrate that the suggested DSS is feasible and applicable and give reliable and robust findings for acquiring the optimal CO2 capture technology.

SPH modeling and investigation of the effect of the carbon dioxide entry form on its absorption rate in a microchannel containing absorbent aqueous solution

Carbon capture technology is a rapidly growing and developing field that has seen extensive research conducted in both experimental and numerical studies. The majority of numerical simulations conducted thus far have primarily concentrated on mesh-based methods, disregarding the potential of full Lagrangian methods in accurately simulating multiphase and intricate flows. Consequently, this research aims to address this gap by introducing, for the first time, the application of the Lagrangian Smoothed Particle Hydrodynamics (SPH) method to simulate and analyze the process of carbon dioxide absorption in an aqueous solution. The first step in this study involves developing a suitable and relatively accurate algorithm based on the governing equations of carbon dioxide absorption. These equations encompass mass and momentum conservation, heat transfer, mass transfer, and chemical reactions. Once the algorithm is developed, it is validated through computational code and the optimal grid of particles is selected for calculations. Subsequently, three different scenarios for the entry of carbon dioxide into the aqueous solution are modeled and discussed. The results reveal that as the number of carbon dioxide inputs increases, the instabilities of the two-phase flow along the microchannel also increase. These instabilities significantly enhance the rate of carbon dioxide absorption. Overall, this study highlights the importance of considering Lagrangian methods, specifically the SPH method, in simulating multiphase and complex flows in carbon capture technology. The findings contribute to a better understanding of the carbon dioxide absorption process and can potentially aid in the development of more efficient carbon capture systems.

Efficiency improvement and flexibility enhancement by molten salt heat storage for integrated gasification chemical-looping combustion combined cycle under partial loads

Chemical-looping combustion offers a promising carbon capture technology for coal-fired power generation. Enhancing the operational flexibility and energy efficiency of such plants is crucial for achieving primary energy savings and renewable energy accommodation. In this study, the operating characteristics of an integrated gasification chemical-looping combustion combined cycle (IGCLCCC) under various loads are studied, and the deterioration mechanism of its thermodynamic performance is revealed. Further, an IGCLCCC scheme coupled with molten salt heat storage is proposed and evaluated from thermodynamic performance and operational flexibility. Study results indicate that the net efficiency of the IGCLCCC reaches 37.7% under 30% load, which is superior to those of conventional CO2 capture power plants under full load. Adopting the heat storage system significantly improves the operational flexibility and energy efficiency of the IGCLCCC by expanding its operating range from 30.0∼100.0% to 25.7∼105.3%. The equivalent round-trip efficiency of the heat storage system reaches 134.6% due to the upgrading of the thermal energy from the exhaust gas of the air turbine from original low levels to high levels driven by the exergy saving during the oxygen carrier-air reaction because of the air preheating to a high temperature.

A study on decompression wave propagation characteristics during CO2 pipeline leakage with consideration of gas‐liquid transition

AbstractPipelines stand as the most cost‐effective method for large‐scale transportation of CO2 from a source point to the storage site, especially over extensive distances. The potential for crack propagation following a pipeline rupture highlights the need for precise analysis of decompression wave propagation. To accurately model this, understanding the decompression wave's propagation laws becomes imperative. Although previous studies have predominantly focused on pipeline leaks within the dense phase or supercritical state, the transition from liquid to gas during leakage significantly affects the decompression wave propagation. When a gaseous CO2 pipeline ruptures, the high Joule‐–Thomson coefficient causes a swift temperature plunge, potentially leading to a gas–liquid transition. However, research on how this phase transition impacts the decompression wave characteristics is limited. To address this gap, this study proposes a transition computational fluid dynamics model to predict the decompression wave behavior. The model is validated with an industrial‐scale full‐bore rupture experiment. The results reveal that the gaseous CO2 leakage induces a pressure plateau at a certain distance from the leakage due to the gas‐liquid phase transition. The influences of initial conditions on this pressure plateau and decompression wave are also explored. This study provides valuable insights into understanding the decompression wave behaviors of gaseous CO2 pipelines, which are essential for ensuring the safety and reliability of CO2 transportation within the carbon capture and storage technology chain. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Research on the influence of mineral heterogeneity under different CO2 injection schemes in low permeability reservoirs

In the pursuit of sustainable oil and gas resource extraction, the innovative integration of carbon capture, utilization, and storage (CCUS) technology has emerged as the most promising approach. During the CCUS process, intricate physicochemical interactions between the injected CO2, facilitated through various injection strategies (Water Alternative Gas: WAG/Continue Gas Injection: CGI) and the formation fluids and heterogeneous mineral assemblages within the reservoir trigger alterations in mineral structures, consequently impacting permeability and recovery factors, constituting a pivotal aspect. Precisely delineating and quantifying these interactions is paramount for optimizing process design and evaluating reservoir dynamics in the successful implementation of CCUS operations. This study has carried out qualitative and quantitative characterization of mineral heterogeneity, different pore types, and mineral combination characteristics from a low-permeability sandstone reservoir. Additionally, the effect on the physical properties of minerals from different development methods (WAG/CGI) was investigated using numerical simulation for CCUS applications. The results indicate that the saturated CO2 fluid selectively dissolves the potassium feldspar (orthoclase) in intergranular pores, while the intergranular pores are filled with illite and secondary precipitated clay minerals. It initially dissolves the sensitive mineral (ankerite) in the intergranular pores. The decrease of ankerite and increase of illite result from the prolonged contact period between saturated CO2 and minerals, which changes the mineral cementation to argillaceous type, thus affecting permeability in the context of CCUS. The spatial impact on reservoir physical properties depends on the spatial heterogeneity of the original sensitive minerals (ankerite, anorthite, illite, etc.) distributed in the study area. In the WAG scheme, the physicochemical interaction between saturated CO2 and reservoir minerals is more intense than in the CGI scheme for CCUS operations, significantly impacting cumulative production.

Mesoporous silica supported ionic liquid materials with high efficacy for CO2 adsorption studies

CO2 capture from industrial processes and power plants, contribute to curbing global warming and advancing sustainability efforts. This study involves the design and synthesis of novel mesoporous silica supported ionic liquid based adsorbents for carbon dioxide capture. Utilization of MSILs delves into the efficiency and mechanisms of CO2 adsorption, offering insights for sustainable carbon capture technologies in combating greenhouse gas emissions. 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium ethyl sulfate and 1-ethyl-3-methylimidazolium methylsulfate ionic liquids were anchored on the surface of mesoporous silica which then led to highly efficient adsorbent material. Simple, efficient and cost saving methodology was performed to synthesize such highly efficient CO2 adsorbent materials. In addition, we theoretically predicted the favorable interaction mechanism of chosen molecular entities for CO2 adsorption using density functional theory (DFT) analysis. Theoretical results depict the strong interaction of molecular entities with CO2 gas molecules which is clearly evident from the experimental findings.

PTFE foam coating ultrafine glass fiber composite filtration material with Ultra-Clean emissions

Bag filters are widely used for dust removal in the industrial applications with filtration materials serving as the critical component. It is meaningful to develop filtration materials with ultra-clean emission effect, as the emitted gas can be proceeded directly by carbon capture technologies. In this study, we introduced a novel approach to fabricate a kind of gradient-structured filtration material by wet-laying ultrafine glass fibers on the surface of aramid fiber needle-punched nonwoven fabrics, followed by PTFE emulsion foam coating. Our PTFE foam coating ultrafine glass fiber composite filtration material demonstrated remarkable filtration performance, achieving a high filtration efficiency up to 99.86 % and a low pressure drop of 87.54 Pa. After undergoing 30 cycles of filtration, the particulate emission concentration was 0.4327 mg m−3. Significantly, this innovative filtration material exhibited exceptional stability, primarily attributable to the surface filtration effect of the PTFE foam coating layer. This innovative design provided a kind of new direction for the flue gas filtration and the emitted clean air can be capture by carbon capture technologies directly.

Mutual Diffusivities of Mixtures of Carbon Dioxide and Hydrogen and Their Solubilities in Brine: Insight from Molecular Simulations.

H2-CO2 mixtures find wide-ranging applications, including their growing significance as synthetic fuels in the transportation industry, relevance in capture technologies for carbon capture and storage, occurrence in subsurface storage of hydrogen, and hydrogenation of carbon dioxide to form hydrocarbons and alcohols. Here, we focus on the thermodynamic properties of H2-CO2 mixtures pertinent to underground hydrogen storage in depleted gas reservoirs. Molecular dynamics simulations are used to compute mutual (Fick) diffusivities for a wide range of pressures (5 to 50 MPa), temperatures (323.15 to 423.15 K), and mixture compositions (hydrogen mole fraction from 0 to 1). At 5 MPa, the computed mutual diffusivities agree within 5% with the kinetic theory of Chapman and Enskog at 423.15 K, albeit exhibiting deviations of up to 25% between 323.15 and 373.15 K. Even at 50 MPa, kinetic theory predictions match computed diffusivities within 15% for mixtures comprising over 80% H2 due to the ideal-gas-like behavior. In mixtures with higher concentrations of CO2, the Moggridge correlation emerges as a dependable substitute for the kinetic theory. Specifically, when the CO2 content reaches 50%, the Moggridge correlation achieves predictions within 10% of the computed Fick diffusivities. Phase equilibria of ternary mixtures involving CO2-H2-NaCl were explored using Gibbs Ensemble (GE) simulations with the Continuous Fractional Component Monte Carlo (CFCMC) technique. The computed solubilities of CO2 and H2 in NaCl brine increased with the fugacity of the respective component but decreased with NaCl concentration (salting out effect). While the solubility of CO2 in NaCl brine decreased in the ternary system compared to the binary CO2-NaCl brine system, the solubility of H2 in NaCl brine increased less in the ternary system compared to the binary H2-NaCl brine system. The cooperative effect of H2-CO2 enhances the H2 solubility while suppressing the CO2 solubility. The water content in the gas phase was found to be intermediate between H2-NaCl brine and CO2-NaCl brine systems. Our findings have implications for hydrogen storage and chemical technologies dealing with CO2-H2 mixtures, particularly where experimental data are lacking, emphasizing the need for reliable thermodynamic data on H2-CO2 mixtures.

Enhancing the CO2 adsorption with dual functionalized coconut shell-hydrochar using Chlorella microalgae and metal oxide: Synthesis, physicochemical properties & mechanism evaluations

This study aims to develop an inexpensive, environmentally-friendly adsorbent for capturing CO2 using coconut shells, widely abundant in Asian agricultural waste. The raw coconut shell adsorbent (CS) has undergone dual functionalization utilizing Chlorella microalgae and magnesium oxide (MgO) to enhance its physicochemical properties. Through dual functionalization, minimizing the loss of surface area and reducing the temperature sensitivity often occurring during CO2 adsorption is possible. The surface morphology, functional groups, and thermochemical properties of CS-hydrochar were characterized and evaluated. The characterization demonstrates the successful development of the ternary composite (HCS-A-Mg), with a specific surface area of 1045 m2/g and containing nitrogen and metal oxide functional groups. XRD analysis of HCS-A-Mg reveals crystalline peaks at 36.8°, 42.9°, and 63°, confirming the successful impregnation of MgO. The adsorption result showed that HCS-A-Mg exhibits a higher CO2 adsorption capacity of 2.63 mmol/g, 50% higher than pristine hydrochar (HCS). The adsorption study revealed that the CO2 adsorption capacity of HCS-A-Mg can be maximized to 3.23 mmol/g at 101 °C and 4.6 bar. Adsorption isotherms shows that the non-linear Sips model best describes the adsorption process, indicating a multilayer adsorption mechanism with profound surface heterogeneity of n = 2.3 for HCS-A-Mg, signifying higher accessibility of gas molecules deep into pores, enabling a variety of adsorption sites for CO2 binding. Selectivity and reusability studies were conducted to validate the adsorbent applicability for industrial applications. HCS-A-Mg has higher CO2/N2 selectivity by 41–57% and 0.05% loss of adsorption capacity after the 10th cyclic operation, suggesting their suitability for industrial applications. This finding underscores the potential of microalgae and magnesium oxide in advancing carbon capture technology and addressing environmental challenges.

Future directions in geological research impacting renewable energy and carbon capture: A synthesis of sustainable management techniques

Geological research plays a pivotal role in shaping the future of renewable energy and carbon capture initiatives, offering insights into sustainable management techniques. This review synthesizes the future directions in geological research that impact renewable energy and carbon capture, focusing on sustainable management techniques. Future geological research will increasingly focus on enhancing the integration of renewable energy sources into existing energy systems. This includes the development of innovative geological mapping techniques to identify and characterize renewable energy resources with greater precision, aiding in the selection of optimal sites for energy production. Additionally, there will be a growing emphasis on utilizing geological data to assess the feasibility of carbon capture and storage (CCS) projects, particularly in volcanic regions, where the unique geological characteristics offer potential for efficient carbon sequestration. Another key aspect of future geological research is the advancement of monitoring and modeling techniques to evaluate the long-term performance and environmental impact of renewable energy and CCS projects. This includes the use of advanced geophysical and geochemical methods to monitor subsurface changes associated with energy extraction and carbon storage, ensuring the effectiveness and safety of these practices. Furthermore, future research will explore the potential of geological formations, such as deep saline aquifers and depleted oil and gas reservoirs, for large-scale carbon storage. This will involve developing strategies to enhance storage capacity and mitigate the risk of CO2 leakage, contributing to the sustainable management of carbon emissions. In conclusion, future geological research will play a critical role in advancing renewable energy and carbon capture technologies, offering sustainable management techniques that are essential for addressing climate change. By focusing on innovative mapping, monitoring, and modeling approaches, researchers can pave the way for a more sustainable energy future.

Sustainability and environmental impact in the LNG value chain: Current trends and future opportunities

The liquefied natural gas (LNG) industry plays a crucial role in the global energy landscape, offering a cleaner alternative to traditional fossil fuels. However, the LNG value chain presents environmental challenges that must be addressed to ensure long-term sustainability. This paper examines current trends and future opportunities for enhancing sustainability and reducing environmental impact across the LNG value chain. The LNG value chain comprises several stages, including natural gas extraction, liquefaction, transportation, regasification, and distribution. Each stage presents unique sustainability challenges, such as methane emissions during extraction and transportation, energy-intensive liquefaction processes, and the carbon footprint of regasification and distribution. Current trends in the LNG industry focus on mitigating these challenges through various strategies. These include the adoption of advanced technologies for methane detection and reduction, the use of renewable energy sources for liquefaction, and the implementation of efficient regasification and distribution practices. Additionally, there is a growing emphasis on stakeholder engagement, transparency, and reporting to enhance sustainability performance across the value chain. Future opportunities for improving sustainability in the LNG value chain lie in the continued development and deployment of innovative technologies. These include carbon capture and storage (CCS) technologies to reduce emissions, the use of renewable natural gas (RNG) as a feedstock, and the integration of LNG with renewable energy sources to create hybrid energy systems. Addressing sustainability and environmental impact in the LNG value chain requires collaboration among industry stakeholders, governments, and regulatory bodies. By implementing best practices, embracing innovation, and prioritizing sustainability, the LNG industry can continue to play a vital role in the transition to a cleaner and more sustainable energy future.

Geological survey techniques and carbon storage: Optimizing renewable energy site selection and carbon sequestration

Geological survey techniques play a crucial role in optimizing site selection for renewable energy projects and identifying suitable locations for carbon storage to mitigate climate change. This abstract provides an overview of how geological survey techniques can be used to achieve these objectives. Renewable energy development, particularly solar and wind power, requires careful site selection to maximize energy generation efficiency and minimize environmental impacts. Geological surveys are instrumental in assessing factors such as subsurface geology, topography, soil composition, and hydrological conditions. These surveys help identify suitable locations with optimal wind or solar resources and geologic conditions for infrastructure development. Additionally, geological surveys are essential for identifying suitable sites for carbon storage, a critical component of carbon capture and storage (CCS) technologies aimed at reducing greenhouse gas emissions. Geological formations, such as deep saline aquifers, depleted oil and gas reservoirs, and unmineable coal seams, can serve as storage reservoirs for captured carbon dioxide (CO2). Geological surveys help characterize these formations to assess their suitability for long-term CO2 storage, considering factors such as porosity, permeability, and sealing integrity. Optimizing site selection for renewable energy projects and carbon storage requires a comprehensive understanding of subsurface geology and environmental conditions. Advanced geological survey techniques, such as seismic imaging, remote sensing, and geophysical surveys, are essential for acquiring detailed subsurface data. These techniques enable scientists and engineers to assess site suitability, evaluate risks, and design effective mitigation measures. In conclusion, geological survey techniques are invaluable tools for optimizing site selection for renewable energy projects and identifying suitable locations for carbon storage. By leveraging these techniques, stakeholders can make informed decisions that promote sustainable energy development and mitigate the impacts of climate change.

Alpha Carbonic Anhydrase from Nitratiruptor tergarcus Engineered for Increased Activity and Thermostability.

The development of carbon capture and storage technologies has resulted in a rising interest in the use of carbonic anhydrases (CAs) for CO2 fixation at elevated temperatures. In this study, we chose to rationally engineer the α-CA (NtCA) from the thermophilic bacterium Nitratiruptor tergarcus, which has been previously suggested to be thermostable by in silico studies. Using a combination of analyses with the DEEPDDG software and available structural knowledge, we selected residues in three regions, namely, the catalytic pocket, the dimeric interface and the surface, in order to increase thermostability and CO2 hydration activity. A total of 13 specific mutations, affecting seven amino acids, were assessed. Single, double and quadruple mutants were produced in Escherichia coli and analyzed. The best-performing mutations that led to improvements in both activity and stability were D168K, a surface mutation, and R210L, a mutation in the dimeric interface. Apart from these, most mutants showed improved thermostability, with mutants R210K and N88K_R210L showing substantial improvements in activity, up to 11-fold. Molecular dynamics simulations, focusing particularly on residue fluctuations, conformational changes and hydrogen bond analysis, elucidated the structural changes imposed by the mutations. Successful engineering of NtCA provided valuable lessons for further engineering of α-CAs.

MODELING AND SIMULATION OF POST-COMBUSTION CO 2 CAPTURE PROCESS FOR 6.4 MWE BAGASSE FUELED POWER PLANT

The emission of carbon dioxide, a greenhouse gas, contributes to the phenomenon of climate change; the largest source of carbon dioxide emissions are fossil fuel power plants. Post-combustion carbon capture (PCC) technology, which is based on solvents, is currently the most advanced technology for reducing carbon dioxide emissions from power plants. The Post-combustion Process, which uses conventional solvents, has a number of disadvantages, including high energy consumption for regeneration, solvent losses, corrosion of equipment, thermal instability, and environmental impact. Ionic liquids (ILs) and IL-based solvents have produced a novel method of CO 2 capture that is highly efficient, economical, and environmentally friendly. A rate-based steady-state model of the PCC process using the ionic liquid 1-hexyl-3-methylimidazolium glycine ([Hmim] [Gly]) was investigated using Aspen Plus ®. In Aspen Plus ® Electrolyte NRTL method and RK equation of state are used to compute liquid and vapor properties. From the process analysis carried out, it was found that the height and diameter of the absorber packing, the liquid-to-gas ratio and the solvent and flue gas temperatures have a positive effect on the CO 2 capture efficiency. The result showed a maximum CO 2 capture efficiency of 92% at a packed height of 12m and diameter of 0.9m. The best capture efficiency of 98.82% was achieved at an L/G ratio of 4.0.the process simulation study examined five key parameters for ([Hmim] [Gly]) solvent which may reduce the energy and cost required for CO 2 capture. The results show that aqueous ([Hmim] [Gly]) is a promising absorbent for CO 2 capture. Offering a pathway towards more sustainable and efficient carbon capture technologies. This study contributes to the advancement of carbon capture technologies and underscores their significance in mitigating climate change impacts.

The valorisation of steel mill off-gas via chain elongation into higher value-added products: A prospective life cycle assessment

Nowadays, one of the greatest challenges for the steel industry is decarbonisation to decrease its pressure on the environment. For this purpose, deploying carbon capture and utilisation technologies such as syngas fermentation can be instrumental, as they allow carbon in steel mill off-gas to be converted into ethanol. However, as ethanol is of relative low value, technologies that can upgrade it towards higher-value chemicals are becoming attractive. One such a technology is chain elongation, as it can convert ethanol effluents from syngas fermentation into caproic acid, which can subsequently be used as a feedstock to produce chemicals such as plasticisers. As information regarding the environmental sustainability of chain elongation is limited, in this study, a prospective environmental hotspot analysis on chain elongation was performed, assessing climate change and resource footprint indicators, from a Life Cycle Assessment perspective, based on a theoretical scale-up. In addition, climate change impacts of a novel basic oxygen furnace gas (BOFG) to plasticiser value chain integrating the theoretically scaled-up chain elongation technology (PLAST) were assessed and compared with two other valorisation routes, considering a US and a European scenario: BOFG incineration with electricity production (ELEC) and syngas fermentation for the production of ethanol for use as a fuel (ETOH). The hotspot analysis showed that electricity and chemicals consumption, mainly K-acetate, were the largest contributors to both the climate change and resource consumption footprint. For the US scenario, the novel PLAST route showed similar climate change impacts to the ETOH route, while the impacts were 15% higher than those of the ELEC pathway. In the European scenario, with a greener electricity mix, the PLAST route showed similar impacts compared to both the ELEC and ETOH routes. Although uncertainties lie within the results, this study highlights the potential of chain elongation as a part of an alternative carbon capture and utilisation pathway for the steel industry. For this however, further technological advances are required, such as changes in process configurations and increases in caproic acid productivity, which should be the focus of future research.

On the Capabilities of Transition Metal Carbides for Carbon Capture and Utilization Technologies.

The search for cheap and active materials for the capture and activation of CO2 has led to many efforts aimed at developing new catalysts. In this context, earth-abundant transition metal carbides (TMCs) have emerged as promising candidates, garnering increased attention in recent decades due to their exceptional refractory properties and resistance to sintering, coking, and sulfur poisoning. In this work, we assess the use of Group 5 TMCs (VC, NbC, and TaC) as potential materials for carbon capture and sequestration/utilization technologies by combining experimental characterization techniques, first-principles-based multiscale modeling, vibrational analysis, and catalytic experiments. Our findings reveal that the stoichiometric phase of VC exhibits weak interactions with CO2, displaying an inability to adsorb or dissociate it. However, VC often exhibits the presence of surface carbon vacancies, leading to significant activation of CO2 at room temperature and facilitating its catalytic hydrogenation. In contrast, stoichiometric NbC and TaC phases exhibit stronger interactions with CO2, capable of adsorbing and even breaking of CO2 at low temperatures, particularly notable in the case of TaC. Nevertheless, NbC and TaC demonstrate poor catalytic performance for CO2 hydrogenation. This work suggests Group 5 TMCs as potential materials for CO2 abatement, emphasizes the importance of surface vacancies in enhancing catalytic activity and adsorption capability, and provides a reference for using the infrared spectra as a unique identifier to detect oxy-carbide phases or surface C vacancies within Group 5 TMCs.

Sponge iron-coupled biochar solution can achieve the synergistic augmentation of carbon sequestration, carbon sink capacity, and denitrification in ecological ditches

Carbon dioxide (CO2) is a more powerful greenhouse gas due to its enhanced instantaneous radiative forcing. Since agricultural ecological ditches (eco-ditches) controlling agricultural non-point source pollution are potential CO2 hotspots, carbon capture technologies must be deployed immediately to sequester carbon and combat climate change. Zero-waste biochar, a negative-carbon technology, remains contentious regarding C sequestration. Iron (Fe) enhances long-term organic carbon (OC) preservation, but the cascading effects of Fe-biochar interactions on the promotion of C accumulation are unclear in eco-ditches. In this paper, we fill these research gaps and employ sponge iron (s-ZVI) and biochar coupling (Fe-C) to enhance the iron gate C protection in eco-ditches. The results reveal that Myriophyllum aquaticum(M.A.)-derived biochar prepared by low-temperature pyrolysis (Biochar_M.A.) enjoys the highest FI, the lowest SUVA254 and SUVA280 and moderate dissolution stability. The coupling of s-ZVI and environmentally compatible Biochar_M.A. achieve a triple benefit situation of C sequestration, C sink, and pollutant removal. Overall carbon gain is jointly determined by abiotic controls and biotic controls. The carbon burial effects of biochar-amended eco-ditches are mainly controlled by the trade-offs between Fe-bound OC mineralization via the biochar-induced prime effect and preservation of OC derived from microbial biomass. The unique Fe-C boosts the rusty sink and yields a negative priming as a result of the dominance of Fe-OC. The upregulated β-glucosidase activity and new-formed Fe-OC indirectly and directly contribute to overall C gain in Fe-C-filled eco-ditches, respectively. These findings provide novel insights into the coupled biotic-abiotic contribution mechanisms underlying the iron gate and reverse enzyme latch phenomenon and advance more robust and prospective theoretical knowledge of C dynamics that are not restricted to eco-ditches, soil, constructed wetlands C storage.

Carbon Dioxide Capture under Low-Pressure Low-Temperature Conditions Using Shaped Recycled Fly Ash Particles

Carbon-capture technologies are extremely abundant, yet they have not been applied extensively worldwide due to their high cost and technological complexities. This research studies the ability of polymerized fly ash to capture carbon dioxide (CO2) under low-pressure and low-temperature conditions via physical adsorption. The research also studies the ability to desorb CO2 due to the high demand for CO2 in different industries. The adsorption–desorption hysteresis was measured using infrared-sensor detection apparatus. The impact of the CO2 injection rate for adsorption, helium injection rate for desorption, temperature, and fly ash contact surface area on the adsorption–desorption hysteresis was investigated. The results showed that change in the CO2 injection rate had little impact on the variation in the adsorption capacity; for all CO2 rate experiments, the adsorption reached more than 90% of the total available adsorption sites. Increasing the temperature caused the polymerized fly ash to expand, thus increasing the available adsorption sites, thus increasing the overall adsorption volume. At low helium rates, desorption was extremely lengthy which resulted in a delayed hysteresis response. This is not favorable since it has a negative impact on the adsorption–desorption cyclic rate. Based on the results, the polymerized fly ash proved to have a high CO2 capture capability and thus can be applied for carbon-capture applications.

Investigating Asphaltene Precipitation and Deposition in Ultra-Low Permeability Reservoirs during CO2-Enhanced Oil Recovery

CO2 flooding is an economically feasible and preferred carbon capture, storage, and utilization technology. Asphaltene deposition is a common problem in the process of CO2 injection because it may cause reservoir damage. The mechanism of asphaltene precipitation damage to the formation remains elusive. Experiments were conducted to reveal the pore-scale formation damage mechanism in ultra-low permeability reservoirs caused by asphaltene precipitation during CO2 flooding. Initially, the precipitation onset point for asphaltene within the crude oil-CO2 system was determined using a high-pressure tank equipped with visual capabilities. Subsequently, CO2 flooding experiments were conducted on ultra-low permeability cores under miscible and immiscible conditions, with the support of nuclear magnetic resonance (NMR) to quantitatively evaluate the impact of asphaltene precipitation on ultra-low permeability reservoirs. The results indicate that within the pressure range from the asphaltene precipitation onset point to the minimum miscibility pressure (MMP). The level of asphaltene precipitation rises as CO2 injection pressure increases. In the miscible flooding stage, asphaltene precipitation can still occur, but to a lesser extent. Notably, asphaltene deposition predominantly occurs in larger pores; above the MMP, the permeability decreases significantly as asphalt particles agglomerate, resulting in notable pore-throat blockages. While asphaltene deposition has a minimal impact on porosity, the bridging effect of asphaltene particles reduces permeability.