Post-combustion Capture Research Articles

Post-combustion CO2 capture retrofit from diesel-powered Arctic mines – Techno-economic and environmental assessment

This study evaluates the economic feasibility and environmental impacts of retrofitting a diesel-based powerhouse in the Canadian Arctic with a post-combustion carbon capture process at an active gold mining site isolated from cheaper or cleaner electrical grids. A techno-economic analysis was conducted to determine the total annualized cost (TAC) of implementing a monoethanolamine (MEA) chemical absorption process to mitigate carbon dioxide emissions. The calculated cost per tonne of CO2 captured of $420 reflects the challenges of operating northern sites reliant on diesel fuel. Electricity generation costs, estimated at 0.44 $/kWh, are found to explain most of the variance in cost per tonne compared to other studies. A profitability model, comparing the additional annual expenditure to the current carbon tax exposure (CTE), suggests that carbon pricing alone is insufficient to incentivize investment in energy-intensive carbon capture technologies such as amine-based absorption processes. The sensitivity analysis, which evaluates profitability relative to variations in key variables, highlights the significant impact of the solvent regeneration heat demand. This major cost driver also contributes substantially to the carbon footprint of 0.55 tonnes emitted per tonne captured, as determined by a complementary life cycle assessment.

Ether chain-modified Alkanolguanidine for CO2 capture and subsequent conversion

Capturing CO2 and converting it into valuable chemicals has attracted considerable attention in recent years. Herein, a kind of ether chain-modified alkanolguanidines (ECMAs) was designed and synthesized as a dual functional reagent for carbon dioxide capture and conversion. Due to the presence of basic sites and CO2-philic ether chains, these ECMAs demonstrated almost equimolar CO2 capture at room temperature and atmospheric pressure through the synergy of physical and chemical absorption. Even for diluted CO2 (15 % CO2), 0.7 mol CO2 per mole capture reagent can still be achieved, showing their potential application in post-combustion capture. The synthesized ECMAs can also serve as catalyst in the cycloaddition reaction of CO2 with various epoxides, affording 75–99 % yield of corresponding cyclic carbonates under 3 MPa CO2 with tetrabutylammonium iodide (TBAI) as co-catalyst. Moreover, these ECMAs can be applied to the integrated CO2 capture and conversion, in which the ECMAs can react with CO2, forming the alkyl carbonate zwitterion as active CO2 species in the capture step. And in the subsequent cycloaddition reaction with propylene oxide, 52 % yield of propylene carbonate was obtained.

Techno-enviro-economic assessment of hydropower-driven decarbonization pathways for Nepalese cement industry

This study presents a comparative techno-enviro-economic assessment of decarbonization measures for the Nepalese cement sector, focusing on post-combustion carbon capture (PCC), use of alternative fuels and oxy-combustion techniques. A typical Nepalese clinker plant is first modelled in Aspen Plus using industrial data, the results of which is then utilized to simulate various decarbonization pathways. Performance of the measures is evaluated based on four performance indicators. The combination of oxy-combustion with hydrogen as fuel (25% thermal substitution rate) is identified as a favorable pathway compared to PCC only and combination of refuse derived fuel and PCC pathways. However, this pathway is sensitive to hydrogen byproduct price. The levelized cost of clinker (LCOC), CO2 abatement cost (CAC), specific electricity consumption for avoided CO2 and carbon intensity for this pathway are 145 USD/tclinker, 98 USD/tCO2, 1.88 MWh/tCO2 and 100 kgCO2/tclinker respectively. The LCOC value for the reference clinker plant without decarbonization is 75 USD/tclinker. The electricity consumption increased by 2153.80%, and the emissions rate decreased by 88%, compared to the reference clinker plant. Capacity utilization rates above 80% are favorable for decarbonization. Sensitivity analysis showed that a 30% decrease in the hydroelectricity cost would lower the LCOC and CAC from base values by 21.160% and 42.379% respectively. Similarly, increasing the tariff rebate to 30% would lower the LCOC and CAC for this case by 12.447% and 24.928% respectively. The results highlight a synergistic relationship between cement industry decarbonization and hydroelectricity utilization, both key targets of Nepal for net zero pathway.

High-temperature carbon dioxide capture in a porous material with terminal zinc hydride sites.

Carbon capture can mitigate point-source carbon dioxide (CO2) emissions, but hurdles remain that impede the widespread adoption of amine-based technologies. Capturing CO2 at temperatures closer to those of many industrial exhaust streams (>200°C) is of interest, although metal oxide absorbents that operate at these temperatures typically exhibit sluggish CO2 absorption kinetics and instability to cycling. Here, we report a porous metal-organic framework featuring terminal zinc hydride sites that reversibly bind CO2 at temperatures above 200°C-conditions that are unprecedented for intrinsically porous materials. Gas adsorption, structural, spectroscopic, and computational analyses elucidate the rapid, reversible nature of this transformation. Extended cycling and breakthrough analyses reveal that the material is capable of deep carbon capture at low CO2 concentrations and high temperatures relevant to postcombustion capture.

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.

Reforming Natural Gas for CO2 Pre-Combustion Capture in Trinary Cycle Power Plant

Today, most of the world’s electric energy is generated by burning hydrocarbon fuels, which causes significant emissions of harmful substances into the atmosphere by thermal power plants. In world practice, flue gas cleaning systems for removing nitrogen oxides, sulfur, and ash are successfully used at power facilities but reducing carbon dioxide emissions at thermal power plants is still difficult for technical and economic reasons. Thus, the introduction of carbon dioxide capture systems at modern power plants is accompanied by a decrease in net efficiency by 8–12%, which determines the high relevance of developing methods for increasing the energy efficiency of modern environmentally friendly power units. This paper presents the results of the development and study of the process flow charts of binary and trinary combined-cycle gas turbines with minimal emissions of harmful substances into the atmosphere. This research revealed that the net efficiency rate of a binary CCGT with integrated post-combustion technology capture is 39.10%; for a binary CCGT with integrated pre-combustion technology capture it is 40.26%; a trinary CCGT with integrated post-combustion technology capture is 40.35%; and for a trinary combined-cycle gas turbine with integrated pre-combustion technology capture it is 41.62%. The highest efficiency of a trinary CCGT with integrated pre-combustion technology capture is due to a reduction in the energy costs for carbon dioxide capture by 5.67 MW—compared to combined-cycle plants with integrated post-combustion technology capture—as well as an increase in the efficiency of the steam–water circuit of the combined-cycle plant by 3.09% relative to binary cycles.

Dynamic modeling of post-combustion carbon capture process based on multi-gate mixture-of-experts incorporating dual-stage attention-based encoder-decoder network

Solvent-based post-combustion carbon capture (PCC) technology is a promising, near-term solution for decarbonizing power generation and industrial facilities. Model-based process simulation is crucial for the optimal design and operation of the PCC process. Recently, data-driven models have gained attention due to their adaptability, efficient computation and high accuracy. However, the nonlinearity, strong couplings and multi-time scale features of the PCC process pose significant challenges for model identification. To this end, this paper proposes a multi-gate mixture-of-experts incorporating dual-stage attention-based encoder-decoder (MMoE-DAED) network for dynamic modeling of the PCC process under wide operating conditions. An encoder-decoder composed of long short-term memory (LSTM) network is employed to extract features from the time-dependent input data and learn the complex dynamic interactions caused by the inertial and delay properties of the process. Dual-stage attention mechanism is incorporated into the encoder and decoder respectively to select the most relevant input features and their correlations within the time series data. To enhance multi-output prediction accuracy, multi-gate mixture-of-experts (MMoE) framework that considers correlations of multitask learning is implemented. Simulation results using operating data from a PCC experimental setup indicate that the proposed modeling approach accurately predicts the steady-state values and dynamic trends of the CO2 capture rate and stripper bottom temperature over a wide operating range. The RMSE, MAPE and R2 indices for the CO2 capture rate are 2.1592, 0.0295, 0.9641, respectively, and for the stripper bottom temperature are 0.1491, 0.0003, 0.9833, respectively. Validations on a PCC simulator further verify the accuracy and efficiency of the MMoE-DAED model, which enables an 80.87% reduction in computation time compared to the simulator. This paper points to a new direction for the data-driven dynamic modeling of complex energy conversion processes.

Enhancing CO2 solubility for efficient carbon capture via self-assembly deep eutectic solvents on MOF-808

The capture of CO2 from flue gas has emerged as the most effective technology for carbon reduction. The relatively low partial pressure of CO2 in flue gas necessitates the development of CO2-selective adsorbents, which provide a direct pathway to obtaining pure CO2 in one-step, thereby reducing energy consumption. Herein, an amino-rich deep eutectic solution (DES) is dispersed on the surface of formate ligand-removed MOF-808 using a self-assembly approach for post-combustion carbon capture. The high solubility of DES towards CO2 enables the composite to effectively capture CO2, with MOF-808 serving as a porous gas storage tank. Material characterization confirms the loading of DES on the surface of MOF support while retaining its microporous structure. Owing to their unique CO2 solution-diffusion mechanism, DES-modified adsorbents exhibit promising performance on CO2 capacity, kinetics, CO2/N2 selectivity, and isosteric heat. The optimized sample DES-2@MOF-808-FR demonstrates a notable CO2 adsorption capacity of 4.16 mmol/g at 298 K and 1 bar. When tested with simulated flue gas (15 vol% CO2), it maintains a working capacity of 2.86 mmol/g and a CO2/N2 selectivity of 1184, surpassing most of existed materials. DES-2@MOF-808-FR can also retain its capacities after 10 adsorption/desorption cycles in simulated flue gas. This solution-based modification approach circumvents the challenges associated with precise structural control of the adsorbent, thereby facilitating potential industrial applications.

Applications of Carbon Capture Technologies in Steel and Cement Industries

As problems such as the increase in extreme weather, rising sea levels, and social inequality continue to sharpen with the intensifying climate change, changes are demanded. The cement and iron and steel industries are among the major spheres responsible for the rising global temperature. Carbon reduction methods cannot fully solve the problem and help these industries reach carbon-neutral emissions. Therefore, carbon capture (CC) technology is urgently needed. This article introduces the application of pre-combustion carbon capture (PreCCC), post-combustion carbon capture (PostCCC), and oxyfuel combustion carbon capture in the cement industry and the iron and steel industry. Research has shown that oxyfuel combustion is one of the most assuring pathways to reach carbon neutrality in cement plants since problems of temperature management can be solved by recycling part of the fuel gases, and its cost is relatively lower than the other methods. However, PostCCC is a better solution in the iron and steel industries. Although technological innovations in physical absorption and chemical absorption are still needed, PostCCC can mitigate a large portion of steel plants carbon footprint. Carbon capture intensity can be increased with further technological development in combining PostCCC and oxygen-rich combustion. The combination of different pathways may be a novel hypothesis, but it has a great possibility of alleviating the carbon emission of the industrial sector.

Comprehensive technical analysis of post-combustion carbon capture and storage based on monoethanolamine absorption for petrochemical industry in Indonesia

Abstract The implementation of carbon capture and storage in the petrochemical industry is one of the means of decarbonization. This research focuses on a comprehensive technical analysis of the deployment of post-combustion carbon capture and storage based on monoethanolamine absorption in the petrochemical industry. The olefin complex petrochemical industry in Tuban, Indonesia, is the basis for the analysis, which includes a steam cracker, polyethylene, polypropylene, and raw pyrolysis gasoline hydrotreating units, with capacities of 1000, 940, 600, and 570 kilotons/year, respectively. The total energy consumption is about 16 024.53 GJ/h, and the CO2 emissions are about 1.6 megatons/year. Based on these plant systems, comprehensive technical analyses of the implementation of carbon capture and storage in that industry were performed using Aspen HYSYS® simulation software. Sensitivity analysis was carried out to determine the total CO2 captured, energy intensity, monoethanolamine consumption, and net CO2 captured in various scenarios based on the number of absorber column stages, absorption pressure, and desorption temperature. The CO2 storage site is about 100 km away and is transported by an onshore pipeline with a supercritical phase of CO2. The optimal net CO2 capture value is achieved by setting up a 50-stage absorber column with a pressure of 1 barg and a temperature of 110°C at the top of the desorber column, resulting in a CO2 capture yield of 86.4% and an energy intensity of 12.6 GJ/ton CO2. Under these conditions, the net CO2 captured in the scenario based on gas power plants’ electricity is 0.225 megatons/year, while in the scenario based on gas power plants incorporating 30% biomass electricity, it is 0.544 megatons/year. With increased use of renewable energy in carbon capture and storage facilities, more net CO2 is captured. This study can be applied to various cases of post-combustion carbon capture and storage implementation in the industrial sector, especially in the petrochemical industry.

Modeling and economic analysis of block absorber (RadFrac) performance with stage variations for post-combustion CO2 capture

This study presents a comprehensive modeling and economic evaluation of a Monoethanolamine (MEA)-based post-combustion carbon capture (PCC) absorber unit. The simulation provides detailed insights into the absorber's internal profiles, including temperature gradients and the percentage of CO2 captured, with a particular focus on the effects of varying the number of stages and absorber diameters. Validation against experimental data demonstrated close alignment between simulated and observed values, with an average Root Mean Square Deviation (RMSD) of 0.018 and 4.0129, respectively, confirming the reliability of the simulation in capturing the complex dynamics of the absorber.The economic analysis, conducted using the Aspen Process Economic Analyzer (APEA), simplified the complex relationship between absorber segmentation, capital and operational costs, and absorber diameter. The study revealed that increasing the absorber diameter and the number of stages leads to a significant rise in Total Capital Cost (TCC), Total Operating Cost (TOC), Equipment Cost, and Total Installed Cost (TIC), with the highest costs observed at a stage number of 90 and a diameter of 1.0 m. However, the analysis identified an optimal configuration at an absorber diameter of 0.45 m with either 10 or 20 stages. This setup effectively balances cost and CO2 capture efficiency, offering a more economical solution compared to configurations with larger diameters and higher stage numbers, which substantially increase expenses. The findings highlight the critical trade-offs between operational efficiency and capital expenditure, stressing on the crucial role of absorber diameter in determining the economic feasibility of the absorber block in PCC systems.

Progress in carbon dioxide capture, storage and monitoring in geological landform

Carbon Capture and Storage (CCS) is recognized as a potent strategy for managing the accumulation of human-generated CO2 in the atmosphere, helping to alleviate climate change’s effects. The CO2 gas is captured from the point source through methods such as pre-treating fossil fuels, oxy-fuel combustion, or post-combustion capture; thereafter; it is transported to a storage location and injected into geological formations. This article provides an overview of carbon dioxide capture and sequestration, focusing on its key principles, technologies, associated risks, and challenges. Direct Air Capture (DAC) and Scalable Modelling, Artificial intelligence (Al), Rapid Theoretical calculations SMART technologies are detailed as emerging and promising approaches to CO2 capture. Numerous pilot and commercial projects commissioned to manage carbon dioxide emissions are presented. Additionally, the paper explores approaches combining geological, geophysical, geochemical, and environmental monitoring techniques to ensure the secure and sustainable storage of CO2 underground. These are essential to address uncertainties, minimize risks, and build public confidence in CCS as a viable climate mitigation strategy. The successful deployment of these technologies on a global scale will require continued innovation, particularly in the areas of monitoring, risk management, and public engagement. Emerging technologies such as AI and SMART systems could play a crucial role in enhancing the efficiency and safety of CCS operations. However, the integration of these advancements with existing infrastructure and regulatory frameworks remains a challenge. Ultimately, a multi-disciplinary approach, combining technological, economic, and regulatory perspectives, will be vital to realizing the full potential of CCS in combating climate change.

Techno-Economic Feasibility Analysis of Post-Combustion Carbon Capture in an NGCC Power Plant in Uzbekistan

As natural gas-fired combined cycle (NGCC) power plants continue to constitute a crucial part of the global energy landscape, their carbon dioxide (CO2) emissions pose a significant challenge to climate goals. This paper evaluates the feasibility of implementing post-combustion carbon capture, storage, and utilization (CCSU) technologies in NGCC power plants for end-of-pipe decarbonization in Uzbekistan. This study simulates and models a 450 MW NGCC power plant block, a first-generation, technically proven solvent—MEA-based CO2 absorption plant—and CO2 compression and pipeline transportation to nearby oil reservoirs to evaluate the technical, economic, and environmental aspects of CCSU integration. Parametric sensitivity analysis is employed to minimize energy consumption in the regeneration process. The economic analysis evaluates the levelized cost of electricity (LCOE) on the basis of capital expenses (CAPEX) and operational expenses (OPEX). The results indicate that CCSU integration can significantly reduce CO2 emissions by more than 1.05 million tonnes annually at a 90% capture rate, although it impacts plant efficiency, which decreases from 55.8% to 46.8% because of the significant amount of low-pressure steam extraction for solvent regeneration at 3.97 GJ/tonne CO2 and multi-stage CO2 compression for pipeline transportation and subsequent storage. Moreover, the CO2 capture, compression, and transportation costs are almost 61 USD per tonne, with an equivalent LCOE increase of approximately 45% from the base case. This paper concludes that while CCSU integration offers a promising path for the decarbonization of NGCC plants in Uzbekistan in the near- and mid-term, its implementation requires massive investments due to the large scale of these plants.

Techno-economic analysis and optimisation of Piperazine-based Post-combustion carbon capture and CO2 compression process for large-scale biomass-fired power plants through simulation

This study aims to investigate a cost-effective and energy-efficient amine-based post-combustion carbon capture (PCC) process for large-scale supercritical biomass-fired power plants (SC BFPP). Thus, we have quantified the energy and economic performance of the PCC process with different configurations and solvents. Three process configurations which included the standard configuration, the absorber intercooler (AIC) with the advanced flash stripper (AFS) and the AIC, AFS and side stream extraction (SSE) were simulated in Aspen Plus® V11 using 30 wt% and 40 wt% piperazine (PZ) as solvent. In addition to this, CO2 compression trains using the heat pump (HP) and supercritical CO2 cycle (s-CO2) were also simulated. Sensitivity analysis of the PCC process was carried out to investigate the impact of important parameters on the energy performance of the process. Furthermore, energy analysis shows that a minimum energy consumption of 2.78 GJ/tCO2 was achieved with the PCC process using 40 wt% PZ, a combination of the AIC, AFS and SSE for capture and s-CO2 for compression. This achieved a significant energy saving of 1.01 GJ/tCO2 compared with the standard PCC process using 30 wt% monoethanolamine that is used as the benchmark in this study. The economic analysis results showed that the minimum CO2 capture cost of 55.70 $/tCO2 was achieved using the AIC-AFS-SSE-sCO2 configuration and 40 wt% PZ as solvent. This represents a 19.5 % reduction in cost compared with the standard 40 wt% PZ process with a cost of 69.18 $/tCO2. The optimisation of the PZ-based PCC process was carried out to determine the optimal solvent concentration with the minimum carbon capture cost. It was found that the optimal PZ concentration for the PCC process based on standard and AFS configurations were 37.5 wt% and 32.5 wt%, respectively. The optimisation of the stripper pressure for the minimum carbon capture cost was conducted. As a result, compared with the standard PCC process using 40 wt% PZ, the energy consumption and CO2 capture cost of the optimised process at the suggested pressure of 7 bar were reduced by 41.6 % and 32.4 %, respectively.

Achieving net zero energy penalty in post-combustion carbon capture through solar Energy: Parabolic trough and photovoltaic technologies

The adoption of carbon capture systems presents a pivotal strategy for mitigating greenhouse gas emissions, notably carbon dioxide. Nevertheless, the substantial surge in energy consumption associated with such systems remains a significant challenge. Addressing this challenge necessitates the integration of renewable energy sources. This study is dedicated to optimizing the conventional post-combustion carbon capture configuration, focusing on energy, exergy, and exergoeconomic considerations. The optimized configuration showcases a noteworthy 10 % reduction in overall energy penalties compared to its conventional counterpart, primarily attributed to diminished energy utilization in the reboiler. To achieve absolute sustainability and eliminate energy penalties in the optimized configuration, integration of a parabolic trough collector for steam provision to the reboiler and photovoltaic solar collectors for powering the plant’s equipment was undertaken. Furthermore, the incorporation of solar thermal storage tanks and batteries enables the storage of excess heat and electricity, ensuring operational continuity for up to 13 h in the absence of sunlight, such as during nighttime. The final optimized configuration manifests a commendable 14 % enhancement in exergoeconomic performance relative to the conventional configuration, thereby realizing zero energy penalties. This achievement renders the optimized configuration a compelling and viable choice for carbon capture units.

Techno-Economic Assessment of Amine-Based Carbon Capture in Waste-to-Energy Incineration Plant Retrofit

This study offers a detailed techno-economic assessment of Carbon Capture (CC) integration in an existing Waste-to-Energy (WtE) incineration plant, focusing on retrofit application. Post-combustion carbon capture using monoethanolamine (MEA) was modeled for various low-scale plant sizes (3000, 6000, and 12,000 t of CO2 per year), using a process simulator, highlighting the feasibility and implications of retrofitting a WtE incineration plant with CC technology. The comprehensive analysis covers the design of the CC plant and a detailed cost evaluation. Capture costs range from 156 EUR/t to 90 EUR/t of CO2. Additionally, integrating the CO2 capture system reduces the overall plant absolute efficiency from 22.7% (without carbon capture) to 22.4%, 22.1%, and 21.5% for the different capture capacities. This research fills a gap in studying small-scale CC applications for the WtE incineration plants, providing critical insights for similar retrofit projects.

Autoignition of methane and methane/hydrogen blends in CO2 bath gas

Combustion in large dilutions of carbon dioxide (CO2) has the potential to enable fossil fuel combustion with 100 % inherent carbon capture by simplifying the post-combustion carbon capture process into the facile separation of CO2 and water. Emerging technologies that employ CO2 as a bath gas, exemplified by the Allam-Fetvedt cycle, are gaining widespread international attention, evidenced by ongoing plant developments in both the United Kingdom and the United States. This study presents new ignition delay time datasets (IDTs) for the combustion of methane and methane/hydrogen blends at 20 and 40 bar. The chemical kinetics governing these distinct conditions are investigated by utilizing two distinct chemical kinetic mechanisms, namely UoS sCO2 2.0 and NUIGMech1.1. Ignition delay datasets of methane/hydrogen blends are presented alongside a detailed discussion of the effect CO2, in contrast to N2, on the combustion mechanism. The differences in kinetics of pure methane and pure hydrogen are also discussed with regards to key reactions and the radical pool. This study aims to elucidate the intricate interplay of factors shaping ignition dynamics in CO2– enriched environments.

A Comparative Review of Post-Combustion Capture and Direct Air Capture of CO2

Mitigating anthropogenic CO2 emissions has been a subject of incredible urgency in recent years. Carbon capture and storage (CCS) has emerged as a promising means of cutting emissions, with post-combustion capture and direct air capture (DAC) both gaining traction as methods of offsetting emissions from point sources and the ambient atmosphere. Each of these carbon capture methods rely on absorbent or adsorbent materials to function, whose properties can vastly impact capture performance. In this work, 14 materials are analyzed, with qualitative descriptions and performance data of each material based on existing review papers and representative case studies being presented. The review highlights limitations in the field in standardizing the reporting of experimental data, complicating the direct comparison of different materials’ efficacies. While no single CCS technology is found to be unequivocally superior, the promising performances of certain materials in earlier stages of development emphasize the importance of investing further in emerging post-combustion capture materials. This study concludes that CCS technologies are a necessary tool in ultimately reaching net zero emissions due to their role in neutralizing sectors resistant to decarbonization, but they should not be relied upon to substitute the transition to renewable energy, as the prevention of emissions should take priority over the abatement of emissions.

Impact of Diluents on Flame Stability With Blends of Natural Gas and Hydrogen

Abstract Two potential decarbonization pathways for natural gas (NG)-fueled gas turbine engines include blending hydrogen (H2) into NG and postcombustion carbon capture. H2 blending changes several combustion properties, including flame speed and stretch sensitivity. The use of post-combustion carbon capture systems is typically facilitated by the implementation of exhaust gas recirculation (EGR), where exhaust gases are injected into the inlet of the engine, increasing carbon dioxide (CO2) concentration at the outlet and, hence, increasing the efficiency of carbon capture technologies. In this work, we explore the impact of H2 blending and EGR on the stability of a swirl-stabilized, central-piloted flame. Mixtures of NG and H2 are tested at a range of different diluent compositions, with oxygen varied from 21% to 15% by volume in the oxidizer. In all cases, a constant adiabatic flame temperature is maintained to mimic the operation of a gas turbine at a given turbine inlet temperature. A variable-length combustor is used for testing, where combustor length is varied to understand the dynamic stability characteristics of the system. Results show that EGR and H2 work in opposition to each other, where higher levels of EGR result in poor flame holding and higher levels of H2 result in better flame holding. Increasing H2 generally increases the amplitude of thermoacoustic instability at each condition, a result of the change in flame position in this particular combustor. Importantly, H2 can be added to NG to improve flame holding without significantly decreasing CO2 levels in the products, showing that H2 blending can be a method for counteracting combustor operability issues that arise from high levels of EGR necessary to improve the efficiency of typical carbon capture systems.