Post-combustion Carbon Capture Technology Research Articles

Comparative multi-aspect study of two scenarios and optimization of the biomass-based cogeneration system integrated with the carbon capture and utilization technology

Combined Heat and Power (CHP) system based on bio-energy is an energy-saving and environment friendly way to utilize energy, but in the background of the "carbon peaking and carbon neutrality" strategy, ensuring low-carbon operation of CHP systems becomes imperative. In this paper, we introduce two distinct CHP system scenarios based on post-combustion carbon capture technologies: a syngas-based gas turbine cycle CHP system (scenario 1) and a biogas-based steam turbine cycle CHP system (scenario 2). Then, a techno-economic evaluation has been conducted to investigate their performance under varying operational conditions of heating and power load, as well as carbon capture technology. The findings reveal that, given the same biomass input rate, the syngas-based CHP system yields superior energy and economic outcomes. To simultaneously mitigate CO2 emissions and reduce electricity costs, a process of multi-objective optimization is employed. This optimization endeavor also focuses on maximizing the overall exergy efficiency. Consequently, scenario 1 experiences substantial improvements in performance metrics. Notably, the overall energy and exergy efficiencies reach 17.32 % and 14.58 % respectively. Additionally, the power and heating load are estimated at 2.58 and 2.17 MW correspondingly. The levelized cost of electricity and heating are assessed at 30.55 USD/MWh and 36.05 USD/GJ, respectively, coinciding with a reduction in CO2 emissions to 98.27 kgCO2/MWh.

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.

Emissions reduction in LNG production facilities through emerging post-combustion carbon capture and storage technologies

The liquefied natural gas (LNG) sector relies extensively on gas turbines for on-site power generation and to drive refrigeration compressors. They provide an efficient and reliable energy source for LNG operations in remote locations. With upcoming changes to the Safeguard Mechanism in Australia, there is an increased focus on Scope 1 emissions, so management and targeted reduction are a priority to reduce liabilities. Despite technology advancements, gas turbines remain one of the largest sources of carbon dioxide (CO2) emissions in LNG production facilities. Also, in Australia, many facilities are not grid-connected, meaning that displacement of Scope 1 emissions through renewable electricity sourcing is a challenge. To develop deeper cuts in Scope 1 emissions, one solution is to deploy post-combustion carbon capture and storage (CCS) on existing gas turbines, with the potential to reduce associated emissions by over 90%. Globally, a number of LNG facilities are already deploying CCS to permanently store reservoir CO2 from the LNG processing trains. Several Australian LNG facilities are located in close proximity to potential CO2 storage reservoirs, meaning that a coordinated approach to both reservoir and post-combustion CO2 should be considered when sizing pipelines, shipping systems and storage wells to optimise and leverage the required investment. This paper outlines the technological, economic and policy aspects of integrating both reservoir post-combustion CCS on LNG facilities, including barriers and opportunities for deployment. It will discuss new developments and enablers for CCS to be more widely deployed at LNG production sites.

Solar-Assisted Carbon Capture Process Integrated with a Natural Gas Combined Cycle (NGCC) Power Plant—A Simulation-Based Study

In the realm of Natural Gas Combined Cycle (NGCC) power plants, it is crucial to prioritize the mitigation of CO2 emissions to ensure environmental sustainability. The integration of post-combustion carbon capture technologies plays a pivotal role in mitigating greenhouse gas emissions enhancing the NGCC’s environmental profile by minimizing its carbon footprint. This research paper presents a comprehensive investigation into the integration of solar thermal energy into the Besmaya Natural Gas Combined Cycle (NGCC) power plant, located in Baghdad, Iraq. Leveraging advanced process simulation and modeling techniques employing Aspen Plus software, the study aims to evaluate the performance and feasibility of augmenting the existing NGCC facility with solar assistance for post-carbon capture. The primary objective of this research is to conduct a thorough simulation of the Besmaya NGCC power plant under its current operational conditions, thereby establishing a baseline for subsequent analyses. Subsequently, a solar-assisted post-combustion capture (PCC) plant is simulated and seamlessly integrated into the existing power infrastructure. To accurately estimate solar thermal power potential at the Baghdad coordinates, the System Advisor Model (SAM) is employed. The integration of solar thermal energy into the NGCC power plant is meticulously examined, and the resulting hybrid system’s technical viability and performance metrics are rigorously evaluated. The paper contributes to the field by providing valuable insights into the technical feasibility and potential benefits of incorporating solar thermal energy into conventional natural gas power generation infrastructure, particularly in the context of the Besmaya NGCC plant in Baghdad. The power generation capacity of the plant was set at 750 MW. With this capacity, the annual CO2 generation was estimated at 2,119,318 tonnes/year which was reduced to 18,064 tonnes/year (a 99% reduction). The findings aim to inform future decisions in the pursuit of sustainable and efficient energy solutions, addressing both environmental concerns and energy security in the region.

Solvent-mediated modification of thermodynamics and kinetics of monoethanolamine regeneration reaction in amine-stripping carbon capture: Computational chemistry study.

A major limitation of amine-based post-combustion carbon capture technology is the necessity to regenerate amines at high temperatures, which dramatically increases operating costs. This paper concludes the effect of solvent choice as a possible route to modify the thermodynamics and kinetics characterizing the involved amine regeneration reactions and discusses whether these modifications can be economically beneficial. We report experimentally benchmarked computational chemistry calculations of monoethanolamine regeneration reactions employing aqueous and non-aqueous solvents with a wide range of dielectric constants. Unlike previous studies, our improved computational chemistry framework could accurately reproduce the right experimental activation energy of zwitterion formation. From the thermodynamics and kinetics of the predicted reactions, the use of non-aqueous solvents with small dielectric constants led to reductions in regeneration Gibbs free energies, activation barriers, and enthalpy changes. This can reduce energy consumption and give an opportunity to run desorption columns at relatively lower temperatures, thus offering the possibility of relying on low-grade waste heat as an energy input.

Technoeconomic evaluation of post-combustion carbon capture technologies on-board a medium range tanker

The international maritime organization has recently set targets and timelines for reducing global greenhouse gas emissions from the maritime industry, which currently stand at 1.1 Gt/year and make 3 % of the global emissions. Reducing emissions by increasing engine efficacy is the immediate target, but there is a limit to how much this path can achieve. Onboard post-combustion carbon capture and concentration in large marine vessels is emerging as an interim approach to reduce maritime emissions until large-scale deployment of low/zero emission fuels become viable. In this paper, we evaluate three carbon capture technologies (chemical absorption using either aqueous MEA or aqueous NH3 as the solvent, cryogenic separation, and membrane separation) for a medium-range tanker for two fuels, namely heavy fuel oil and liquefied natural gas. The capture cost per tonne of CO2 (recovery>90 %, purity>95 %) was considered as the assessment criterion, with simultaneous evaluation of other aspects such as energy and space demands. The simulations were carried out using MATLAB and ASPEN V12. For rate-based models, the adjustable parameters for the model were tuned using pilot plant data. Additionally, options for hot and cold energy integration were also assessed and implemented. Based on the reference ship conditions and assessment criteria, the simulation studies show that amine-based absorption is the best prospect for on-board capture by a clear margin.

Progress in Post-Combustion Technology for Carbon Dioxide Capture

In the face of climate change and global warming caused by the increase in atmospheric carbon dioxide released by the combustion of fossil fuels, carbon capture technologies become pivotal for mitigating greenhouse gas emissions, particularly carbon dioxide. Among these carbon capture technologies, post-combustion capture has gained widespread application. In this article, the absorption and adsorption methods in post-combustion carbon capture technology, including the mechanism of the chemical and physical aspects of both methods as well as the absorbents and adsorbent materials used in them, will be specifically introduced. Moreover, the current and potential applications in the field of emissions reduction are also elaborated. These post-combustion carbon capture methods are expected to reduce environmental harm while maintaining energy efficiency, providing an effective solution to the problem of global warming.

Heat and mass transfer of a novel CO2 desorption process integrated with highly turbulent catalytic heat exchanger

This was the first work that pioneered the development a novel catalytic CO2 desorption process using an agitated jacket vessel with a coil heat exchanger (JVC) into a bench-scale pilot plant for post-combustion carbon capture technology. The key parameters of heat and mass transport e.g., overall heat transfer coefficient, overall volumetric liquid-side mass transfer coefficient and the enhancement factor for catalyst effect, were experimentally investigated by varying the operating conditions, including temperature, stirring speed, and heating methods. The proposed investigations revealed that the utilization of the JVC was a promising technology for improving heat transfer and mass transfer performance in the desorption process due to the high turbulence flow and more favorable thermal distributions achieved by the JVC. In comparison to the conventional process with a fixed catalyst bed, the JVC demonstrated a remarkable approximately 30 % catalytic enhancement and a substantial 50 % reduction in catalyst demand. Additionally, other potential benefits and challenges of further practical operations were discussed in this paper. This research carried significant potential to contribute to the advancement of knowledge and offer valuable insights into the practicability of the catalytic desorption process for further commercial application in carbon capture. The integration of catalyst and JVC could potentially motivate the utilization of catalyst towards commercial-scale applications.

Analysis of CO2 capture process from flue-gases in combined cycle gas turbine power plant using post-combustion capture technology

Combined cycle gas turbine power plants (CCGTs) are a combined cycle consisting of a gas turbine and a steam turbine to generate electricity. Sometimes CCGTs incorporate cogeneration to produce both heat and power. After the gas fuel combustion in the gas turbine combustion chamber, the flue gases are passed through the Heat Recovery Steam Generator (HRSG) to extract heat and generate additional electrical power using the steam turbine. The CCGT technology is recognized for its highest efficiency of 58% in electricity production among the power production technology. A highly efficient CCGT power plant with 60% efficiency produces even 2.5 times less CO2 than a modern coal power plant with an efficiency of 45% because of the use of gas fuel and electrical efficiency. The CO2 emission can be reduced further when the post-combustion CO2 capture methods are applied. To perform CO2 capture and to reduce the CO2 emission from power plants, the CO2 mass fraction in flue gas is the crucial parameter for the operation of the Post-combustion Carbon Capture and Storage (PCCS) technology. The PCCS technology uses solvents, which is the aqueous solution of amine that reacts with flue gas and absorbs the CO2, which is treated and separated later. The paper presents the results of the energy analysis of a post-combustion carbon capture process when integrated with a combined cycle gas power plant. The study considered two different gas fuels such as methane and syngas. Syngas composition was determined from the sewage sludge gasification process and can be treated as zero-emission CO2 gas fuel. When the flue gas produced from the syngas is used in PCCS at more than 50% of load conditions, the negative CO2 emission level in large-scale CCGT power plants can be reached. The paper presents the results of mass and energy balance analysis of HRSG of a CCGT integrated with PCCS to perform CO2 capture. The analysis of HRSG using flue gases from methane and syngas is performed by calculating the enthalpy of flue gas, rate of heat exchange, and temperature distribution of each component of HRSG. The comparison of the result shows slight differences due to the different composition and flow rates of flue gases. The flue gas at the outlet of two HRSG is used in the PCCS at different load conditions. An aqueous solution of 30 wt% Monoethanolamine (MEA) with rich loading of 0.5 mol-CO2/mol-MEA and a mixture of 16 wt% 2-amino-2-methyl-1-propanol (AMP) – 14 wt% Piperazine (PZ) with rich loading of 0.62 and 0.86 mol-CO2/mol-amine respectively are used in the PCCS. Due to the reboiler duty of amines, the steam consumed by the PCCS for AMP-PZ regeneration is less compared to MEA. Depending upon the flue gas and solvent used in the PCCS, the power consumed by the PCCS from CCGT power plant is measured from 9.6% to 11.6%. For the given operating condition of the CCGT and PCCS at more than 50% load condition, the negative CO2 emission level can be achieved.

Demonstration of CO2 Capture Process Monitoring and Solvent Degradation Detection by Chemometrics at the Technology Centre Mongstad CO2 Capture Plant

Solvent management is one of the important current challenges in post combustion carbon capture (PCC) technology development. Using large-scale 1960 h test campaign data (Technology Centre Mongstad, Norway, 2015 MEA Test), we demonstrate a combination of multivariate methods (PLS-R, MSPC) and process analytical spectroscopy (FT-IR) as a tool to monitor and control PCC process performance. Two MEA solvent monitoring models, total inorganic carbon (TIC) content and total alkalinity (TA), were prepared. In long-term solvent monitoring, PLS-R model prediction uncertainty increased due to gradual solvent changes, e.g., solvent degradation and impurity accumulation. Hence, we show a specific model update methodology to keep the models updated, leading to good long-term monitoring ability of the TIC and TA models. In addition to reliable long-term solvent monitoring ability, a new principle for follow-up of thermal solvent reclaiming was demonstrated. This shows that the need for solvent reclaiming can be quantified. Furthermore, this methodology is an indicator to see the actual solvent deviation from the fresh solvent. This quantification may provide an input for “start” and “end of reclaiming operation” identification. Hence, we demonstrate that it is possible to extract information for process performance follow-up, solvent monitoring, and solvent reclaiming from a single spectroscopic instrument.

Process simulation and techno-economic analysis on novel CO2 capture technologies for fluid catalytic cracking units

To reduce CO2 emissions in the FCC process, the post-combustion carbon capture and storage (CCS) technology has been first applied in the FCC process due to its ease of retrofit. However, the required chemicals and high energy consumption turn it into a high-cost method. Oxy-fuel combustion, with the use of different advanced air separation units (ASU), has the potential to be a cost-effective technology for carbon capture in the FCC system. This study first develops steady state models of a 1.4 Mt./a resid FCC unit operated in two carbon capture conditions, namely post-combustion and oxy-fuel combustion, by using Aspen Plus. Second, it compares the economic performances of three different ASUs in oxy-fuel combustion, which are cryogenic ASU, pressure swing adsorption (PSA) ASU, and vacuum pressure swing adsorption (VPSA) ASU. A comparative study on the performances of the industrial-scale CCS FCCUs is conducted for a comprehensive analysis. The analysis shows that the power consumption of the whole system reduces by 30–50 MW when adopting the oxy-firing method, as compared to the post-combustion technology. The air-firing FCC unit with a VPSA air separation unit has the highest NPV and IRR (511.76 M$ and 23.45%) among these technologies. It presents the best performance in all aspects including CO2 recovery rate, energy consumption, and economics, which promises to become strongly competitive in CCS technologies of FCCUs.

Comparative techno-economic analysis of the integration of MEA-based scrubbing and silica PEI adsorbent-based CO2 capture processes into cement plants

The objective of this work was to perform the techno-economic analysis for the integration of two post-combustion carbon capture technologies into cement plants, namely monoethanolamine (MEA) scrubbing-based and silica-alkoxylated polyethyleneimine (SPEI) adsorbent-based processes. The key performance indicators were investigated, including emission abatement, energy performance, break-even selling price, CO2 capture and avoidance cost. The technical evaluation showed that the conventional MEA and SPEI-based processes required 3.53 GJ/tonne CO2 and 2.36 GJ/tonne CO2 of regeneration energy when achieving 90% of CO2 capture rate, respectively. In addition, the specific primary energy consumption for CO2 avoided was estimated at 6.5 GJ/tonne CO2 for the MEA-based and 4.3 GJ/tonne CO2 for the SPEI-based process. The CO2 capture costs of MEA and SPEI-based processes were estimated at 61.4 and 49.8 €/tonne CO2, respectively. Meanwhile, the CO2 avoidance cost of MEA and SPEI processes were estimated at 84.7 and 62.2 €/tonne CO2 respectively. The economic evaluation indicated that the cost of clinker production was increased by 108% with the integration of the solvent-based MEA-based and 84% for the SPEI-based processes. However, in the case, the maximum heat of 53.9 MWth is recovered from the reference cement plant, the costs of CO2 capture and CO2 avoidance for both the MEA and SPEI-based processes would be reduced. The CO2 capture costs of MEA and SPEI-based processes would decrease to 48.0 and 35.6 €/tonne CO2, respectively. Additionally, the CO2 avoidance costs for the MEA and SPEI-based processes would be reduced to 57.5 and 44.5 €/tonne CO2, respectively.

Use of artificial intelligence in reducing energy costs of a post-combustion carbon capture plant

Absorption-based carbon capture (ACC) is the most mature technology for abating CO2 among different post-combustion carbon capture technologies. ACC is, however, energy-intensive and requires large heating and cooling utility consumption, resulting in high operational costs. Reliable and fast estimation of these utility consumptions would be valuable for technical and financial feasibility assessment of different ACC process designs. The objective of this study is to develop an artificial intelligence (AI) based approach that predicts these utility consumptions of different ACC process designs. For prediction of specific reboiler duty, which is the most important energy consumption of the plant and the main source of operational costs in the ACC process, the error of the AI models is between 0.4% and 3.6% for different scenarios of utilizing either limited or extensive training data. Moreover, the contribution of each process parameter to energy consumption was identified using explainable artificial intelligence. The findings of this study facilitate the energy-efficient design of ACC plants and provide a prioritized list of parameters to adjust for reducing the energy consumption of an ACC process.

Process simulation and energy analysis of synthetic natural gas production from water electrolysis and CO2 capture in a waste incinerator

Power-to-gas (PtG) and carbon capture and utilisation are expected to play a key role in promoting a sustainable energy transition. In this work, a detailed energy analysis of a complete PtG system integrated with a real waste incinerator is performed. A fraction of the renewable electricity and heat produced by the waste incinerator is used in the PtG system to produce hydrogen, which is further converted into SNG by methanation with CO2 recovered from the plant flue gases. A PtG plant able to produce up to 500 m3/h of SNG is considered. A total of six different plant configurations are analysed, obtained by the combination of different electrolysis and post-combustion carbon capture technologies. Specifically, alkaline and PEM electrolysers are considered for the production of hydrogen, while absorption with monoethanolamine solution, absorption with monoethanolamine and ionic liquid solution, and temperature swing adsorption with solid sorbent are selected for carbon capture. The main sections of the PtG system are modelled and the performance of the overall system is evaluated by computing key performance indicators, such as the global energy efficiency and the Specific Plant Energy Consumption for CO2 Avoided (SPECCA). Special attention is also paid to the thermal integration between the methanation unit and the carbon capture unit. The heat produced during the methanation process is sufficient to cover the entire heat demand of the CO2 capture unit in almost all configurations investigated. In particular, thermal integration increases the global energy efficiency by 5–9% and reduces the SPECCA indicator by 5–8%. Considering the thermally integrated configurations, the global energy efficiency is estimated to be between 44.6% and 46.7%, while the SPECCA value ranges from 40.5 MJ/kg to 42.4 MJ/kg. Finally, some technical considerations are given, including the quality of SNG produced and the degradation phenomena in the considered technologies.

Low Carbon Economic Dispatch of Integrated Energy System Considering Power-to-Gas Heat Recovery and Carbon Capture

Carbon capture and storage (CCS) is an effective means to achieve the goals of carbon peaking and carbon neutrality. To improve the operating economics and low-carbon emission of an integrated energy system, the strong exothermic property of power-to-gas is utilized for heat recovery and injection into the heat network. This expands the adjustable range of electric output of combined heat and power (CHP) units which will improve wind power accommodation. The CO2 produced by the coal-fired unit is captured using post-combustion carbon capture technology, and then stored and used to manufacture methane, in order to realize the electric–gas–heat integrated energy system coupled with power-to-gas. Based on the ladder-type carbon trading mechanism, a low-carbon economic dispatch model of integrated energy system is proposed, which considers the incorporation of power-to-gas heat recovery and carbon capture and storage. The objective function is to minimize the total operation cost of the system. The model is simulated in the revised IEEE 39-bus power network, Belgium 20-node gas network and 6-node heat network by CPLEX solver and simulation results verify the effectiveness of the proposed model.

Decarbonization of Power and Industrial Sectors: The Role of Membrane Processes.

Carbon dioxide (CO2) is the single largest contributor to climate change due to its increased emissions since global industrialization began. Carbon Capture, Storage, and Utilization (CCSU) is regarded as a promising strategy to mitigate climate change, reducing the atmospheric concentration of CO2 from power and industrial activities. Post-combustion carbon capture (PCC) is necessary to implement CCSU into existing facilities without changing the combustion block. In this study, the recent research on various PCC technologies is discussed, along with the membrane technology for PCC, emphasizing the different types of membranes and their gas separation performances. Additionally, an overall comparison of membrane separation technology with respect to other PCC methods is implemented based on six different key parameters-CO2 purity and recovery, technological maturity, scalability, environmental concerns, and capital and operational expenditures. In general, membrane separation is found to be the most competitive technique in conventional absorption as long as the highly-performed membrane materials and the technology itself reach the full commercialization stage. Recent updates on the main characteristics of different flue gas streams and the Technology Readiness Levels (TRL) of each PCC technology are also provided with a brief discussion of their latest progresses.

Cost projection of combined cycle power plants equipped with post-combustion carbon capture

This work aims to analyze the cost projection of natural gas combined cycles (NGCC) with post-combustion carbon capture (PCC) technology for two promising power plant configurations, namely: conventional NGCC and exhaust gas recirculation (EGR). A thermo-economic analysis was performed considering the second-law efficiency for the CO2 separation process (η2nd) and the CO2 avoided cost (CAC) as main indicators. Several critical variables influencing the overall cost of the plant were considered, such as the work required for solvent regeneration (Wregen), technology maturity, learning rate, carbon tax credit, and carbon capture level (85%, 90%, and 95%). A hybrid method combining engineering-economic and experience-curve approaches was used to estimate the costs of Nth-of-a-kind (NOAK) plants. The results showed that NOAK plants could potentially decrease the levelized cost of electricity (LCOE) by 10%–11%, and the CAC by 21%–23%, compared with first-of-a-kind (FOAK) plants. EGR at 85% capture level showed the best economic performance among the study cases evaluated, with a CAC equal to $102.5/tCO2. At an 85% capture level, the CAC for the conventional NOAK NGCC plant is $104.1/tCO2; maintaining this same CAC value, the carbon capture rate could increase from 85% to 90.8% if EGR configuration is implemented. Finally, from the findings of this research, it is concluded that the CAC for NOAK plants is expected to be, in the best scenario, as low as $69/tCO2. Therefore, these plants might need at least a similar carbon tax value to ensure their operation during their useful life.

Prospect of Post-Combustion Carbon Capture Technology and Its Impact on the Circular Economy

The sudden increase in the concentration of carbon dioxide (CO2) in the atmosphere due to the high dependency on fossil products has created the need for an urgent solution to mitigate this challenge. Global warming, which is a direct result of excessive CO2 emissions into the atmosphere, is one major issue that the world is trying to curb, especially in the 21st Century where most energy generation mediums operate using fossil products. This investigation considered a number of materials ideal for the capturing of CO2 in the post-combustion process. The application of aqueous ammonia, amine solutions, ionic liquids, and activated carbons is thoroughly discussed. Notable challenges are impeding their advancement, which are clearly expatiated in the report. Some merits and demerits of these technologies are also presented. Future research directions for each of these technologies are also analyzed and explained in detail. Furthermore, the impact of post-combustion CO2 capture on the circular economy is also presented.

Study on CO2 absorption-mineralization characteristics of mixed amine solution coupled with CaO and key influencing factors in mineralization process

Amine CO2 capture is an effective post-combustion carbon capture (PCC) technology, while CO2 mineral carbonation is a safe and stable method for CO2 storage. In this paper, these two methods were combined, and the CO2 absorption-mineralization performance of mixed amine solution coupled with CaO under different ratios of mixed amine solution, temperature, reaction time and CaO addition ratio were studied by using MEA/MDEA mixed amine solution as the CO2 absorbent and using CaO as the CO2 mineralizing raw material. The results show that CaO could effectively mineralize the CO2 absorbed in MEA/MDEA solution, realizing the regeneration of MEA/MDEA solution simultaneously under normal temperature and pressure. Meanwhile, the MEA/MDEA solution can still maintain a high CO2 conversion rate (77.4%) and CO2 cycle loading (1.03 mol/L) after five cycles of absorption-mineralization experiments. The FT-IR and XRD analyses reveal that the addition of CaO makes a large amount of Ca2+ and OH− into the MEA/MDEA solution, which could react with and protonated amine in the solution to form calcium carbonate precipitate and free amine respectively, thus realizing the mineralization of CO2 and the regeneration of MEA/MDEA solution. The main component of solid products obtained is calcium carbonate, and calcite is its main crystal form.

Nanostructured AlOOH – A promising catalyst to reduce energy consumption for amine-based CO2 capture

In order to alleviate the intensive energy demand of amine-based post-combustion carbon capture technology, metal oxyhydroxide AlOOH of nanoscale was synthesized through the hydrothermal method and applied to accelerate the CO2 desorption rate and reduce the regeneration heat duty of aqueous monoethanolamine (MEA) solution for the first time. Results showed that the use of AlOOH could accelerate the desorption rate by up to 560% and increase the desorption amount by 251%. By comparing the performance between AlOOH and Al2O3, it can be found that the presence of extra hydroxyl groups is 20.6% more efficient in catalyzing CO2 desorption. According to a simplified heat transfer model created in this work, AlOOH could reduce the heat duty by 17% with only 0.1 wt% loading, which exhibited the highest performance cost ratio among related literature. In addition, the cyclic stability of AlOOH was confirmed through various characterization methods, including XRD, FT-IR, SEM, and N2 adsorption–desorption. More importantly, a possible catalytic mechanism of AlOOH was discussed and proved where it could change reaction pathways in different CO2 loading regions. This work reveals a promising research direction towards cost-efficient and high-performance metal oxyhydroxide catalysts in the catalytic amine regeneration field to approach the net-zero carbon emission goal.