Carbon Capture Technologies Research Articles

Exploring the diffusion of low-carbon power generation and energy storage technologies under electricity market reform in China: An agent-based modeling framework for power sector

Promoting the widespread adoption of multi-complementary low carbon power generation technologies is a fundamental strategy for attaining carbon neutrality within the electricity sector. In the context of electricity market reform, this study develops an agent-based modeling framework integrated simulation with optimization. The model uses agent-based simulation to analyze annual market dynamics and low-carbon technology diffusion, with a two-stage optimization for energy storage and spot market simulation. The research findings indicate: (1) For different power generation technologies, the spot market can establish differentiated average prices, making the market price of carbon-captured coal power higher than that of conventional coal power, which are advantageous in reducing the subsidies required to promote the diffusion of carbon capture technology. (2) Expanding the spot market scale and implementing differentiated capacity compensation mechanisms both promote carbon capture technology diffusion. Nevertheless, with the marginal clearing mechanism, thermal power holds a average price advantage than renewable energy. Failing to control the growth of thermal power capacity will result in increased carbon emissions. (3) After 2030, energy storage's role in balancing supply and demand grows. Storage capacity should align with renewable energy scale and the regional characteristics of wind and solar resources to prevent overbuilding and stranded assets.

Life Cycle Assessment of CO2-Based and Conventional Methanol Production Pathways in Thailand

Methanol production through carbon capture and utilization technologies offers promising alternatives to traditional natural-gas-based methods, potentially mitigating climate change impacts and improving resource efficiency. This study evaluates four methanol production pathways: CO2 hydrogenation, tri-reforming of methane, electrochemical CO2 reduction, and co-electrolysis of CO2 and water. The analysis covers 19 scenarios, combining three electricity mixes (100% Thai grid mix, 50% Thai grid mix and 50% renewable energy, and 100% renewable energy) with two hydrogen production technologies (alkaline water electrolysis and grey hydrogen). Environmental life cycle assessment results showed that most pathways perform well when using the 100% renewable energy with co-electrolysis (CE-100%) showing the most substantial reductions across all impact categories as compared conventional methanol production. Electrochemical reduction demonstrated the poorest environmental performance for all scenarios. In Thailand, implementing the CE-100% pathway could potentially yield 12.4 million tonnes of methanol annually from the cement industry’s CO2 emissions, with an estimated value of approximately USD 5.4 billion, while reducing emissions from the industrial processes and product use (IPPU) sector by 75%. The findings provide valuable insights for policymakers, industry stakeholders, and researchers, supporting Thailand’s transition towards sustainable methanol production and broader climate goals.

Performance analysis of precooling systems for cryogenic carbon capture: A comparative study of theoretical, numerical, and experimental methods

The urgency of addressing climate change has necessitated innovative and practical approaches to reducing greenhouse gas emissions. Cryogenic Carbon Capture (CCC) technology has emerged as a promising solution for capturing CO2 from industrial emissions. This study investigates a simplified design for a precooling system within CCC technology, focusing on optimizing the efficiency and reliability of the system while minimizing energy consumption. The research examines the effects of CO2 concentration in a gas mixture (simulated flue gas, nitrogen and carbon dioxide), cooling bath temperature, and gas mixture flow rate on the performance of heat exchangers in the precooling system. Theoretical, numerical, and experimental analyses were conducted to assess the system's performance. The use of liquid nitrogen at −196 °C in the cooling bath was found unsuitable due to CO2 freezing within the pipes. Instead, a mixture of dry ice and isopropyl alcohol at −78.5 °C proved effective in maintaining consistent temperature and pressure conditions without causing CO2 blockages. Numerical simulations highlighted the importance of optimizing pipe length to balance temperature control and pressure dynamics, with a 140 cm pipe length identified as optimal for heat exchanger design. Experimental results revealed that longer pipes enhance cooling performance due to increased heat exchange surface area, while higher CO2 compositions and flow rates result in higher outlet temperatures and pressures. The study emphasizes the need for further research and simulation work to refine heat exchanger designs for industrial applications, aiming to develop systems that maximize cooling efficiency while ensuring reliable operation.

Enhancing life cycle assessment methodologies for carbon capture and utilization technologies: A comprehensive guideline for improved decision-making

Carbon Capture Utilization and Storage (CCUS) is an emerging technology that aims to reduce carbon dioxide (CO₂) emissions from industrial processes and power generation. This paper presents a comprehensive Life Cycle Analysis (LCA) of CCUS, evaluating its environmental impacts from cradle to grave. The LCA includes the stages of CO₂ capture, transportation, utilization, and storage. The goal is to provide a holistic understanding of the potential benefits and drawbacks of CCUS, guiding policymakers and industry stakeholders in decision-making processes. Although LCA is a standardized method, there is significant variability in current LCA practices due to differing methodological choices, which limits their effectiveness for decision support. Applying LCA to CCU technologies introduces additional challenges, particularly because CO₂ serves both as an emission and a feedstock. The guidelines aim to enhance the comparability of LCA studies by providing clear methodological directions and predefined assumptions regarding feedstock and utilities. Increased transparency is achieved through detailed interpretation and reporting guidance. By improving comparability, the guidelines support more informed decision-making, enabling more efficient allocation of research funds and time towards the development of technologies for climate change mitigation and negative emissions.

The competitive edge of Norway's hydrogen by 2030: Socio-environmental considerations

Can Norway be an important hydrogen exporter to the European Union (EU) by 2030? We explore three scenarios in which Norway's hydrogen export market may develop: A Business-as-usual, B Moderate Onshore, C Accelerated Offshore. Applying a sector-coupled energy system model, we examine the techno-economic viability, spatial and socio-economic considerations for blue and green hydrogen export in the form of ammonia by ship. Our results estimate the costs of low-carbon hydrogen to be 3.5–7.3€/kg hydrogen. While Norway may be cost-competitive in blue hydrogen exports to the EU, its sustainability is limited by the reliance on natural gas and the nascent infrastructure for carbon transport and storage. For green hydrogen exports, Norway may leverage its strong relations with the EU, but is less cost-competitive than countries like Chile and Morocco, which benefit from cheaper solar power. For all scenarios, significant land use is needed to generate enough renewable energy. Developing a green hydrogen-based export market requires policy support and strategic investments in technology, infrastructure and stakeholder engagement, ensuring a more equitable distribution of renewable installations across Norway and national security in the north. Using carbon capture and storage technologies and offshore wind to decarbonise the offshore platforms is a win-win solution that would leave more electricity for developing new industries and demonstrate the economic viability of these technologies. Finally, for Norway to become a key hydrogen exporter to the EU will require a balanced approach that emphasises public acceptance and careful land use management to avoid costly consequences.

Critical Assessment of Provisional Application of Environmental Treaty in the Facilities of CCS Projects

Removing legal barriers of carbon capture and storage project requires a provisional application of treaty related. And the Vienna Convention on the Law of Treaties as well as the Guide to Provisional Application of Treaties provide the law basis for such application of treaties. The positive role of such application in promoting the implementation of carbon capture and storage technologies explains its unique functions as a tool under international emergency, especially when it comes to environmental law. Nevertheless, the issue raised from that the provisional application of treaties shall not be underestimated. It can be found that the practice of provisional application may lead to the instability of the effectiveness of the treaty, the impairment of the integrity of the treaty as a whole, as well as the possibly imposing challenge on the interaction between provisionally applied treaty and the domestic law.

Optimal scheduling of multiple entities in virtual power plant based on the master-slave game

As the energy market evolves into a dynamic and interactive landscape, the distributed nature of virtual power plant (VPP) becomes increasingly significant. This shift highlights the limitations of traditional centralized optimization approaches in capturing the complex interplay among various stakeholders. In response, this article introduces a novel multi-entity distributed collaborative optimization strategy for an integrated energy system (IES) that incorporates a VPP, electric vehicles, and carbon capture technologies, under the Stackelberg master-slave game framework. Within this framework, the VPP operator (VPPO) assumes the role of the leader, while the energy supply aggregator (ESA), customer side residential load aggregator (CSRLA), electric vehicles aggregator (EVA), and carbon treatment system aggregator (CTSA) are positioned as the followers. The paper delves into the development of interaction strategies for each entity, aiming at achieving optimal objectives. The study undergoes by presenting the mathematical model of the VPP-integrated energy system, which is seamlessly integrated into the master-slave game structure. This integration facilitates the creation of a distributed multi-entity cooperative optimization model featuring a single leader and multiple followers, with the uniqueness of the Stackelberg equilibrium being rigorously established. Therefore, the research employs a hybrid nutcracker optimization algorithm and quadratic programming (NOA-QP) method to address the engineering challenge of optimizing operator energy pricing. The case study conducted demonstrates that the proposed scheduling methodology improves the VPP system profit by 10.80%, increases the aggregation profit by up to 1317.22%, optimizes the carbon emissions by 15.59%, and significantly improves the solution efficiency of the VPP by 99.29%.

Techno-economic assessment for the practicability of on-board CO2 capture in ICE vehicles

The transport sector is a major energy-intensive and significant contributor to CO2 emissions. With heavy-duty internal combustion engine vehicles (HD-ICEVs) set to remain a primary mode of transport for goods and passengers, the European Union plans to implement CO2 emission rights starting in 2027 to address this issue. To mitigate CO2 emissions, on-board carbon capture technologies can be an innovative solution, but a comprehensive analysis from several perspectives must be carried out. To tackle the existing knowledge gap on this subject, this paper presents the techno-economic assessment of a CO2 capture and storage system hybridised with an organic Rankine cycle (CCS-ORC) integrated into an HD-ICEV whose technical ability has been previously demonstrated. In this paper, the capture installation based on temperature swing adsorption is designed for two engines with different displacement volumes, at varying carbon capture rates (CCR), and using three different sorbents. The size of the thermal devices is estimated as the determinant factor for the required space and the installation costs. The results show that the heat exchangers can achieve a minimum area density of 100 m2/m3, while the most significant temperature swing adsorption device obtained is scarcely 0.26 m3. The carbon abatement cost (CAC) obtained for the CCS-ORC system is less than 35 €/tCO2 at 100 % of CCR, and with an engine size greater than 18 and 21 L, the CAC of the CCS-ORC system is zero at 100 and 70 % of CCR, respectively. Furthermore, with a CO2 emissions right price above 71 €/tCO2, the projected payback of the initial investment of the CCS-ORC system is achieved in the lifespan of the HD-ICEV for all sorbents evaluated at 100 % of CCR.

Establishment of a one-dimensional model for CO2 Pipeline rupture process and design recommendations

Pipelines serve as a critical means of transporting CO2 within Carbon Capture, Utilization, and Storage (CCUS) technology. Elevated transport pressures may lead to unforeseen pipeline ruptures. To provide practical recommendations for the design of CO2 pipelines and mitigate the risk of ruptures, this study establishes a one-dimensional Homogeneous Equilibrium Mixture (HEM) model. The model is currently used to predict the decompression behavior in existing pure CO2 rupture tests. Future work will address rupture tests and predictions involving impure CO2. The results indicate that due to differences in pressure reduction caused by decompression waves, the likelihood of long-range ruptures occurring in density CO2 pipelines is lower compared to supercritical CO2 pipelines. The crack propagation velocity and crack arrest pressure of pipelines designed according to ASME B31.3 are calculated using the High Strength Line Pipe Committee (HLP) model. Although the crack propagation velocity is lower than the decompression wave speed, the crack arrest pressure may fall below the rupture pressure, with the pressure at 1.6 m from the rupture point remaining above the crack arrest level for 1 ms post-rupture, a duration that is especially prolonged in larger-diameter pipelines. It is recommended to consider additional thickness beyond the calculated minimum thickness.

A Comprehensive Review of Carbon Capture, Utilization, and Storage (CCUS): Technological Advances, Environmental Impact, and Economic Feasibility

Carbon capture, utilisation, and storage (CCUS) technologies are critical to reducing CO2 exhalations on a global scale. This review study synthesizes the many elements of CCUS over 50 years, from R&D to deployment scales, in terms of their mitigation potential for global emission reductions. Next, it discusses existing and new carbon capture techniques from an automation standpoint (e.g., pre-combustion capture, post-combustion capture combustion), as well as the economic feasibility of CCUS regionally in terms of capital retail price, operating expenses, and value in the form of potential revenue streams based on CO2, aided by significant range-scaling building blocks such as rising nation. Each technique is thoroughly evaluated in terms of its environmental impact and associated risks, and case studies are used to illustrate practical lessons learnt. The paper also discusses the arguments around what future advances may exist in CCUS technology, and opportunities to scale these up (including research needs for this support), drawing lessons past policy. The findings underscore the importance of integrating CCUS into broader climate strategies to achieve net-zero exhalations while addressing the economic and environmental challenges that remain.

Induction of lipid production through controlled acidification: A transcriptional insight into the metabolism of Scenedesmus obtusiusculus AT-UAM

Scenedesmus obtusiusculus AT-UAM was able to accumulate up to 62 % of lipids when controlled acidification was applied to a nitrogen-deplete culture. Under these conditions, up-regulation of genes related to lipid synthesis and central carbon metabolism (glycolysis, the tricarboxylic acid cycle, and the pentose phosphate pathway) was recorded. Additionally, genes related to photosynthesis were up-regulated in the nitrogen depletion and nitrogen depletion with controlled acidification conditions with respect to the control samples analyzed under nutritional sufficiency. The Pyani program was used to establish pairwise ANI values between reported and annotated NCBI genomes to uphold genomics similarity. ANI analysis confirms the previously observed identity of S. obtusiusculus AT-UAM with the 18S rRNA and ITS2 regions, and also provides a solid framework for understanding the genetic stability and lineage of the strain. Results obtained are encouraging for integrating biofuel production processes and carbon capture technologies. Specifically, the up-regulation of genes related to both lipid synthesis and photosynthesis under controlled conditions indicates the potential of S. obtusiusculus AT-UAM for efficient biofuel production while simultaneously sequestering carbon. These biochemical properties make this strain a promising candidate for sustainable energy solutions and environmental mitigation strategies.

Life Cycle Carbon Assessment of Mortars with Carbonated and Non-Carbonated Recycled Aggregates

Global warming is one of the most important issues that the world is currently facing. The cement industry accounts for around 7% of total global CO2 emissions. According to the 13th United Nations Sustainable Development Goals, cement plants must become carbon neutral by 2050. This neutrality may be achieved by a reduction in CO2 emissions complemented with carbon capture, utilization and storage (CCUS) technologies. In accordance with these sustainable goals, several approaches have been studied. This paper investigates life cycle carbon of mortars produced with carbonated recycled aggregates. In previous works, the carbon dioxide capture capacity of construction and demolition waste (CDW) was analysed, and mortars with CDW recycled aggregates submitted to high levels of CO2 were evaluated in terms of their mechanical performance. This paper focus on the life cycle carbon impact assessment (LCCA) of industrial mortar formulations in a cradle-to-gate boundary. This assessment is carried out through a global warming potential environment impact assessment, since it represents the amount of CO2 equivalent that is sent to the atmosphere and contributes to the “greenhouse effect”. This LCCA includes the impacts associated with the treatment and additional transportation routes of the recycled aggregates. With this work, it was found that mortars with carbonated recycled aggregates have a considerably lower global warming potential impact than mortars without recycled aggregates. The mortars with recycled aggregates presented lower CO2 emissions of up to 6.31% for 100% incorporation of non-carbonated recycled aggregates. These values were incremented with the carbonation of the recycled aggregates, achieving a reduction of CO2 emissions of up to 36.75% for 100% of incorporation.

Structure–activity relationship of a dual-function amine-based electrolyte for integrated CO2 capture and electrochemical conversion

Integrated carbon dioxide (CO2) capture and electrocatalytic reduction processes through dual-function amine-based electrolytes and their integration into a single reactor can lead to significant energy savings, simplified process flow, and reduced transportation risks. This work investigates the structure–activity relationship of dual-functional amine-based electrolytes for CO2 capture and electrocatalytic reduction and develops an efficient dual-functional amine-based electrolyte system. We investigated 10 different amine-based solutions for their CO2 capture and reduction performances. The substituents on the nitrogen atom of the intermediate carbamate and the positions of the hydroxyl and branched groups affect the capture and electrochemical reduction. The 1,3-propanediamine system demonstrated enhanced CO2 solubility uptake (58.1 %), Faradaic efficiency (10.6 %), and current density (52.1 %) compared with the monoethanolamine system, indicating its potential as a dual-function amine-based electrolyte. Furthermore, density functional theory calculations indicated that the charge distribution of carbamate and the dissociation of C–N bonds directly influence the adsorption of carbamates on the electrode surface and the Faradaic efficiency of the reduced products. In addition, reaction path analysis based on the zwitterionic mechanism indicated that intermediates (carbamate R1R2NCOO-) with higher electronegativity are more conducive to adsorb onto the electrode surface and inhibit hydrogen generation from protonated amines (R1R2NHH+). The results suggest that the selection or design of dual-functional amine-based electrolytes should prioritize amines with straight alkanol chains rather than branched ones, which do not form intramolecular hydrogen bonds or heterocyclic structures. This work provides directions and guidance for designing and developing dual-functional electrolytes for integrated carbon capture and electrocatalytic conversion technologies.

Enzymatic CO2 Capture in intensified packed-bed column bioreactors: A techno-economic assessment

To reduce the impact of industrial carbon dioxide (CO2) emissions on climate change, energy-efficient and cost-effective carbon capture technologies are needed. With this in mind, our research group has proposed an intensified enzyme-mediated CO2 capture process in packed-bed column bioreactors with carbonic anhydrase (CA) immobilized on the packing surface and on magnetic nanoparticles (MNPs). This study, in continuation of our efforts to amend these processes, aims to showcase a techno-economic assessment (TEA) of this promising technology in an industrial-scale context and to emphasize the inherent benefits of intensification. The TEA results suggest that this enzyme-mediated technology has the potential to reduce capture costs, chiefly due to the possibility of utilizing an alternative solvent that requires less energy to regenerate, while also being non-corrosive and non-toxic. The capture process consumes 39.8% less energy than the benchmark process utilizing a MEA-based solution. Immobilizing the enzyme on MNPs has tangible benefits, such as enhancing mass transfer and reducing the equipment footprint, which improves flexibility and contributes to the viability of the industrial process. The intensified enzyme-mediated CO2 capture process achieves a 28.6% reduction in capture cost compared to the benchmark technology. Sensitivity analyses were conducted to highlight the impact of key parameters on the overall cost-effectiveness of the technology, providing beneficial insights for further improvement. The results indicate that it is crucial to maximize enzyme lifespan and minimize energy consumption. The liquid flow rate and buffer concentration are additional constraints that should be thoughtfully considered to ensure the feasibility of this process.

CCUS source-sink matching model based on sink well placement optimization

Realizing the dual-carbon target is a major strategic plan made by the Party Central Committee and a solemn commitment to address climate change of global significance. Source-sink matching technology in carbon capture, utilization, and storage (CCUS) technology is crucial to achieving the dual-carbon target. However, most previous studies constructed source-sink matching models based on sink-fixed sequestration potential, making it difficult to accurately assess the potential of sequestration sites and thus affect the source-sink matching scheme. Therefore, a dynamic storage potential assessment model has been established which can quickly assess the injection capacity of sinks under different well deployment schemes and then a source-sink matching model based on the overall optimization of sink deployment schemes has been constructed by combining the dynamic storage potential assessment model. The model considers the source matching problem as a mixed-integer linear programming (MILP) problem and obtains the computational results of the dynamic storage potential assessment model to realize the correct matching and simultaneous optimization of the source-sink pipeline network layout and the sink-well deployment scheme. With the proposed model, source-sink matching cases for national-level and project-level have been analyzed. It has been shown that the dynamic storage potential assessment model and the combined method improve the accuracy of the source-sink matching model in the form of MILP while minimizing the total cost and additional computations.

Estimation of CO2-Brine Interfacial Tension Based on an Advanced Intelligent Algorithm Model: Application for Carbon Saline Aquifer Sequestration.

The emission reduction of the main greenhouse gas, CO2, can be achieved via carbon capture, utilization, and storage (CCUS) technology. Geological carbon storage (GCS) projects, especially CO2 storage in deep saline aquifers, are the most promising methods for meeting the net zero emission goal. The safety and efficiency of CO2 saline aquifer storage are primarily controlled by structural and capillary trapping, which are significantly influenced by the interactions between fluid and solid phases in terms of the interfacial tension (IFT) between the injected CO2 and brine at the reservoir site. In this study, a model based on the random forest (RF) model and the Bayesian optimization (BO) algorithm was developed to estimate the IFT between the pure and impure gas-brine binary systems for application to CO2 saline aquifer sequestration. Then three heuristic algorithms were applied to validate the accuracy and efficiency of the established model. The results of this study indicate that among the four mixed models, the Bayesian optimized random forest model fits the experimental data with the smallest root-mean-square error (RMSE = 1.7705) and mean absolute percentage error (MAPE = 2.0687%) and a high coefficient of determination (R2 = 0.9729). Then the IFT values predicted via this model were used as an input parameter to estimate the CO2 sequestration capacity of saline aquifers at different depths in the Tarim Basin of Xinjiang, China. The burial depth had a limited influence on the CO2 storage capacity.

Promoting the sustainable development of CCUS projects: A multi-source data-driven location decision optimization framework

Carbon Capture, Utilization, and Storage (CCUS) technology is vital for achieving global carbon reduction targets. However, the uncertainties in technology and economic viability are influenced by location. To promote the sustainable development of CCUS technology, the study proposes a data-driven framework for optimizing location decisions. Firstly, the framework considers multiple factors, including geospatial data on resources, risks, power production, transportation, and environment. It also evaluates qualitative and quantitative data across economic, social, environmental, and technological dimensions. Secondly, the two-stage model is conducted as follows: Using Geographic Information System (GIS) technology, the first stage identifies suitable regions for CCUS projects, while the second stage prioritizes these regions using the TODIM method. Further, validated in China, the Junggar Basin, Tarim Basin, Ordos Basin, Sichuan Basin, and Bohai Rim Basin are identified as suitable for CCUS deployment. The Huaneng Luohuang Power Plant is the most conducive location for CCUS projects as pilot demonstrations. Final sensitivity analysis, scenario analysis, and comparative analysis have respectively affirmed the stability, dynamism, and reliability of the model. These analyses have also been instrumental in elucidating the final preferred outcomes under various decision-making preferences and strategic orientations. The framework for decision-making and data-driven priority model for CCUS projects layout proposed in the study can provide technical support and practical evidence for decision-makers in planning CCUS projects and formulating supportive policies.

Effects of pore characteristics on CO2 adsorption performance of coal slime with different metamorphic degrees

With the rapid development of Carbon Capture, Utilization and Storage (CCUS) technology, it is necessary to explore the feasibility of coal slime as a porous carbon material for CO2 capture. In this paper, scanning electron microscopy (SEM) was used to observe the morphological characteristics of coal slime samples with different metamorphic degrees, and the pore structure of coal slime was explored by low temperature N2 adsorption and low-pressure CO2 adsorption experiments. The pore distribution characteristics were analyzed, and the adsorption law of different metamorphic degrees were summarized through CO2 isothermal adsorption experiments. The results showed that: The specific surface area (SSA) and pore volume (PV) of the mesopores of the coal slime exhibited a U-shaped distribution with coal rank, and are much smaller than that of its micropores. Micropores less than 2 nm are the main adsorption space of coal slime, its PV accounted for 59%, 60%, 71%, and SSA accounted for 92%, 93%, 95%, obviously, which are dominant at all stages. The linear correlation fitting coefficients R2 between the limiting adsorbed amount a of CO2 and the micropores PV and the SSA were up to 0.830 and 0.887, respectively. The coal slime has good adsorption performance for CO2. Based on the Langmuir model to fit the limit adsorption amount, a-value can reach 41.774 cm3 g−1, 32.072 cm3 g−1, 38.457 cm3 g−1 at 303 K with the increase of Rmax. Studying the impact of coal slime on CO2 adsorption performance provides a theoretical basis for the subsequent preparation of energy storage materials and is of great significance for the safe, efficient and economic capture and sequestration of CO2, to alleviate the serious situation of the environment and realizing the dual-carbon goal.

Polymer-modified nanofillers for enhancing CO2 separation performance of MMMs: A comparative study on the role of bridging ligands

Advanced CO2 separation technology is one of the key technologies for reducing carbon emissions and can make significant contributions to reducing the negative impact of the greenhouse effect on human survival. Membrane separation technology is regarded as a new generation of carbon capture technology because of its great potential to reduce carbon capture energy consumption and improve net carbon capture efficiency. Mixed matrix membranes (MMMs) can break through the performance limit of traditional polymer membranes, but the influence of bridging agents for post-modifying nanofillers on membrane structure and properties needs further systematic investigation. In this work, four types of ligands were selected for synthesizing polymer-modified nanofillers and then incorporated into poly (vinylamine) (PVAm) to prepare MMMs. The comparative analysis results indicate that bridging ligands with superior flexibility are conducive to enhancing the gas permeability within the pores by diminishing the compactness of the polymer shell. The constructed phase interface transition area with uniformly enhanced mechanical strength demonstrates the improved interface compatibility between the matrix and nanofillers bridged via the flexible ligand. Techno-economic evaluation verifies the industrial application potential of the optimal MMMs targeting CO2 capture from post-combustion gas.

CFD modeling investigation of oxy-fuel combustion application in an industrial-scale FCC regenerator

The increase in atmospheric CO2 concentration and its consequential impact on climate change have elicited increased public concern. The refinery units including fluid catalytic cracking (FCC) generate substantial quantities of CO2. To mitigate the emission from the FCC process, oxy-fuel combustion has emerged as a prospective carbon capture and storage technology. This study presents the first trial for the modeling investigation of a 70 kt/a industrial FCC regenerator under the scenario of retrofitting it with oxy-fuel combustion technology. Employing the Eulerian-Eulerian model, a CFD model integrating heat transfer and coke combustion reactions has been established. The detailed hydrodynamics, temperature, and species concentration distribution inside the regenerator are obtained under both air-firing and oxy-firing conditions, which are further compared to exploit the possibility of oxy-fuel combustion retrofitting. As has been found, decreases in gas temperature and carbon conversion rate were observed for 21 % O2/79 % CO2 atmosphere in comparison to the air reference case due to the differences in gas properties between N2 and CO2. This discrepancy resulted in a drop of 17 K in dilute phase temperature and 2 K in dense phase temperature. The bed density also exhibited a large with the oxy-firing conditions, with notable observations revealing a lower bed density below a height of 4.2 m, transitioning to a higher density above said height. Sensitivity analysis was also conducted for three principal operating parameters, including superficial gas velocity, oxygen partial pressure, and catalyst circulation rate. An increase of oxygen partial pressure to 27 % or a decrease of the catalyst circulation rate to 20.7 kg/s proved effective in achieving the same temperature profile and even a slightly better carbon conversion in comparison to air-firing regeneration.