Post-combustion Carbon Capture Research Articles

Achieving sustainable emissions in China: Techno-economic analysis of post-combustion carbon capture unit retrofitted to WTE plants

China's aims of achieving CO2 emissions peak by 2030 and carbon neutrality by 2060 are crucial in guiding international efforts to mitigate climate change. Amine-based solvent technologies for capturing CO2 on a large scale have been implemented as retrofits in various industrial facilities, with a particular focus on coal-fired power plants. Nonetheless, its implementation within the waste-to-energy (WTE) industry is considerably limited and non-existent in China. This work presents a technical and economic evaluation of retrofitting a generic WTE facility in China with a carbon capture system. A rate-based process simulation model of the capture plant was developed in Aspen Plus, and the effect of equipment installation factors on capital cost was evaluated via the enhanced detailed factor (EDF) method. A set of key performance indicators were evaluated. The findings indicate that the energy demand linked to the capture system caused a decrease in efficiency by 13.17%, 14.85%, and 16.56% at 85%, 90%, and 95% capture rates, respectively, and the overall exergy efficiency of the system was reduced by 5.5%, 8.27%, and 10.63%, respectively. The estimated CO2 captured costs range from €56.41/tCO2 to €58.95/tCO2, while CO2 avoided costs range from €153.33/tCO2 to €236.47/tCO2. Retrofitting a CO2 capture unit at WTE facilities has the potential to substantially contribute to achieving the country's emission reduction targets. However, the successful implementation requires a comprehensive policy structure. This work offers some insights into the prospective integration of CO2 capture technology in China's WTE industry.

Economic modelling of flexible carbon capture and storage in a decarbonised electricity system

This research provides new techno-economic insights into integrating flexible combined-cycle gas turbines with post-combustion carbon capture and storage (CCGT-CCS) for low-carbon power systems. This study developed a versatile unit-commitment optimisation model of CCGT-CCS. This research highlights the model’s adaptability, accommodating diverse techno-economic configurations, feed gases (e.g., biomethane or fossil natural gas), carbon capture rates, and policy instruments. This generalisation empowers seamless application in various policy and market contexts, making the model a potent tool for researchers and policymakers. While the case study focuses on the UK, the findings are relevant for most low-carbon power systems with variable renewable supplies. Analysing the UK’s net-zero scenarios from 2030 to 2050, the economic viability of flexible CCGT-CCS was highlighted. Intertemporal flexibility proves highly valuable with greater electricity price volatility, with a total ROI range of 81–246 %, surpassing the CCGT-CCS plant’s ROI (7–64 %). A flexible solvent storage solution should be seen in the context of the overall system ‘flexibility’ requirements of a low-carbon power system. On a cost basis, solvent storage represents just a fraction of the capital costs of more “mainstream” energy storage technologies, such as lithium-ion batteries or hydro-pumped storage, while CCGT-CCS offers firm power. Overall, while seen as a rather technical solution, if abated fossil fuel generation is to be part of a future low-carbon power system, having this flexibility adds economic benefits not just to operators but also improves overall system security and complements high shares of variable renewables on the grid.

Effects of pressure and temperature on CO2 facilitation of amino acid salt-containing membranes for post-combustion carbon capture

Polymeric facilitated transport membranes (FTMs) that contain amino acid salts (AASs) provide a cost-effective option for reducing the CO2 emissions associated with burning fossil fuels. In the current work, we examined the effects of CO2 partial pressure and temperature on the CO2 absorption properties of three AAS mobile carriers, piperazine glycinate (PZ-Gly), 2-(1-piperazinyl)ethylamine glycinate (PZEA-Gly), and 2-(1-piperazinyl)ethylamine sarcosinate (PZEA-Sar), and their facilitation of CO2 transport by employing 13C NMR spectroscopy. The CO2 loading and the distribution of reaction products, i.e., carbamate and bicarbonate products, were analyzed and quantified for each AAS sample. The 13C NMR analysis revealed that PZEA-Sar had a greater CO2 loading and favored the more efficient bicarbonate pathway in comparison to PZ-Gly and PZEA-Gly. In addition, we noted marked differences in the formation of carbamate and bicarbonate products when the CO2 partial pressure and temperature were adjusted. The concentration gradient of the reaction products formed indicated that the diffusion of carbamate products was the most influential factor in CO2 transport under reduced CO2 partial pressure. However, as the partial pressure of CO2 increased, bicarbonate products began to play a more significant role. At elevated temperatures, a lower absorption of CO2 was observed, resulting in the reduced generation of both reaction products. This suggests that the enhanced CO2 permeance of FTMs is mainly attributed to the accelerated diffusion of the reaction products. The findings of this study contribute to a comprehensive understanding of the transport mechanism by which AAS carriers enhance CO2 facilitation, allowing for the refinement of more efficient FTM designs.

Application of post-combustion carbon capture process in marine diesel engine

ABSTRACT This study has investigated the effect of using a waste heat recovery system and carbon capture process on carbon reduction efficiency and the Energy Efficiency Design Index (EEDI) to reduce carbon emissions from ships. Organic Rankine Cycle (ORC) was used as waste heat recovery and ORC system turbine power was determined at variable engine loads. The effect of system parameters such as exhaust absorber inlet temperature, MEA concentration and flow rate, number of columns on carbon capture performance has been revealed in the carbon capture process. Furthermore, the EEDI was estimated using the existing system, the ORC system configuration, and the utilization of the carbon capture system. It has been determined that the optimal exhaust absorber inlet temperature is 50°C and the carbon capture performance is 95% on average. In the applied system, the EEDI is reduced by 14% with the ORC system and by 90% with the carbon capture system. ORC system turbine output power ranges from approximately 414 kW to 606 kW for variable CCS inlet temperatures for 100% load condition. Thus, the study predicts that the carbon capture system can effectively meet the regulations in case of using fossil fuels in the future.

Exploring Performance and Cost Trade-Offs in Electrochemical CO2 Separation Processes

Increasing global energy demand coupled with a continued reliance on carbon-intensive fuels has contributed to the rise in anthropogenic greenhouse gas emissions that are adversely impacting the global climate.1,2 While the expansion of low-cost renewable electricity (often coupled with energy storage) offsets fossil-fuel-based generation, complete mitigation of carbon emissions will likely require the capture, utilization, and/or storage of carbon dioxide (CO2) at scale. Today’s state-of-the-art separation technologies rely on thermochemical processes to extract CO2 from industrial waste streams, post-combustion flue gases, or directly from the atmosphere. Such approaches are energetically intensive and typically rely on fossil-fuel-derived heat to release CO2 and regenerate the sorbent, ultimately limiting process effectiveness.3 Electrochemical approaches to CO2 capture and concentration are increasingly seen as a viable pathway to reducing carbon emissions, as these processes enable several advantages including direct integration with renewables, modular deployment, operation near ambient conditions, and high energetic efficiencies.4 Despite this promise, these concepts are at an early-stage and the relationships between cost and performance are not well-understood at the molecular-, cell-, or system-level.In this presentation, we will discuss how techno-economic modeling can be used to inform design criteria for cost-competitive electrochemical CO2 separation systems. We will specifically focus on a 4-stage system with soluble redox-active species for direct binding / debinding with CO2. First, we describe and integrate all process units (i.e., electrochemical reactor, absorber, desorber) via thermodynamic, chemical, and electrochemical relationships and then estimate capital, fixed, and variable costs via a levelized cost of capture model. Second, we investigate key scaling correlations and cost sensitivities for the 4-stage system, including the role of resistive losses in the electrochemical reactor and binding affinity in the absorption column. Third and finally, we connect system-level performance and cost targets to molecular / system properties and operating envelopes. While our focus is on a particular system, the framework is generalizable and can be extended to different electrochemical and thermochemical approaches to CO2 separation, potentially enabling technology comparisons on a common basis. Acknowledgements This work was supported by the Alfred P. Sloan Foundation. K.M.R. gratefully acknowledges the support of the National Defense Science and Engineering Graduate (NDSEG) Fellowship. References Ritchie, H., Roser, M. & Rosado, P. CO2 and Greenhouse Gas Emissions. Our World in Data (2020). Annual Energy Outlook 2021. U.S. Energy Information Administration (2021).Khan, F. M., Krishnamoorthi, V. & Mahmud, T. Modelling reactive absorption of CO2 in packed columns for post-combustion carbon capture applications. Chemical Engineering Research and Design 89, 9, 1600–1608 (2011).Renfrew, S. E., Starr, D. E. & Strasser, P. Electrochemical Approaches toward CO2 Capture and Concentration. ACS Catal. 10, 21, 13058–13074 (2020).

Machine learning based modelling and optimization of post-combustion carbon capture process using MEA supporting carbon neutrality

The role of carbon capture technology using monoethanolamine (MEA) is critical for achieving the carbon-neutrality goal. However, maintaining the efficient operation of the post-combustion carbon capture is challenging considering the hyperdimensional design space and nonlinear characteristics of the process. In this work, CO2 capture level from the flue gas in the absorption column is investigated for the post-combustion carbon capture process using MEA. Artificial neural network (ANN) and support vector machine (SVM) models are constructed to model CO2 capture level under extensive hyperparameters tuning. The comparative performance analysis based on external validation test confirmed the superior modelling and generalization ability of ANN for the carbon capture process. Later, partial derivative-based sensitivity analysis is carried out and it is the found that absorbent-based input variables like lean solvent temperature and lean solvent flow rate are the two most significant input variables on CO2 capture level in the absorption column. The optimization problem with the ANN model embedded in the nonlinear programming-based optimization environment is solved under different operating scenarios to determine the optimum operating ranges for the input variables corresponding to the maximum CO2 capture level. This research presents the optimum operating conditions for CO2 removal from the flue gas for the post-combustion carbon capture process using MEA that contributes to achieving the carbon neutrality goal.

Robust real-time optimization and parameter estimation of post-combustion CO2 capture under economic uncertainty

The operational cost of post-combustion carbon capture remains the principal factor impeding its uptake, thus real-time optimization has been proposed for economic operation. This requires that uncertainties be estimated, subjecting its solutions to estimation error. Herein, we propose uncertainty estimation and real-time optimization for post-combustion carbon capture plants. Model parameters are estimated using noisy measurements to address model uncertainty; accordingly, we deploy a low-variance scheme to address noise propagation. Our approach is implemented in a pilot-scale carbon capture plant through uncertain flue gas compositions and thermodynamic activities. The proposed method results in operating points closer to the true optima, with up to 25% improvement in economics compared to alternative operational approaches. Moreover, a robust real-time optimization strategy is proposed for cases in which model parameters and economic factors are simultaneously uncertain. The robust update strategy is deployed jointly with the low-variance estimation scheme to quantify the uncertainty in each model parameter, resulting in economic improvements and a notable reduction (80%) in the set point variability over the standard update approach. Through the schemes proposed, the carbon capture plant was able to operate at set points with high capture rates, low energy consumption, and low cost. This suggests that the proposed approach is suitable for the economic optimization of other energy and carbon capture systems.

Effect of water on CO2 absorption by a novel anhydrous biphasic absorbent: Phase change behavior, absorption performance, reaction heat, and absorption mechanism

The ionic liquids (ILs)-based biphasic absorbents are viewed as promising substitutes for CO2 capture due to their remarkable CO2 absorption performance, excellent stability and low energy requirement for regeneration. Further decreasing the regeneration heat requirement can be achieved by utilizing ILs-based anhydrous biphasic absorbents, whose solid CO2-rich phase contained small volume and low specific heat capacity. Given the high hygroscopicity of ILs and the water present in the flue gas, comprehending the effect of water is crucial for post-combustion carbon capture using ILs-based anhydrous biphasic absorbents. In this work, the effect of water on CO2 absorption by an anhydrous biphasic absorbent, tetramethylammonium glycinate ([N1111][Gly])/ethanol, was studied. The experimental results demonstrated that the CO2 loading and absorption rate were decreased in the presence of water, but the CO2 desorption efficiency was enhanced. Besides, the presence of water slightly reduced the reaction heat of CO2 absorption by [N1111][Gly]/ethanol to 69.48 kJ/mol CO2, which was 20% lower than that of monoethanolamine (MEA) absorbent. Furthermore, the 13C NMR results indicated that the primary CO2-product was bicarbonate in the presence of water rather than carbamate. There were three possible pathways for bicarbonate generation: zwitterion hydrolysis, carbamate hydrolysis, and base-catalyzed CO2 hydration. Water and ethanol competed to react with carbamate. When a large amount of water was present (≥70 wt%), the reaction of ethanol with the carbamate hardly occurred.

Carbon Dioxide Capture by Adsorption in a Model Hydroxy-Modified Graphene Pore.

Concerns regarding the environmental impact of increasing levels of anthropogenic carbon dioxide have led to a variety of studies examining solid surfaces for their ability to trap this greenhouse gas (GHG). Atmospheric or post-combustion carbon capture requires an efficient separation of carbon dioxide and nitrogen gas. We used the molecular mechanics MM3 parameter set (previously shown to provide good estimates of molecule-surface binding energies) to calculate theoretical surface binding energies for carbon dioxide ∆E(CO2) and nitrogen ∆E(N2). For efficient separation, differentiation of these two gas-surface adsorption energies is required. Examined structures based on graphene, carbon slit width pore, and carbon nanotube gave ∆E(CO2) to ∆E(N2) ratios of 1.7, 1.8, and 1.9, respectively. To enhance the CO2 adsorption, we developed a model graphene surface pore lined with four hydroxy groups whose orientation allowed them to form hydrogen bonds with the oxygens in CO2. Both the single-layer and double-layer versions of this pore gave significant enhancement in the ability to trap CO2 preferentially to N2. The two-layer version of this pore gave ∆E(CO2) = 73 and ∆E(N2) = 6.8 kJ/mol. The one- and two-layer versions of this novel pore averaged a ∆E(CO2) to ∆E(N2) ratio of 12.

Carbon Capture Membranes Based on Amorphous Polyether Nanofilms Enabled by Thickness Confinement and Interfacial Engineering.

Thin-film composite membranes are a leading technology for post-combustion carbon capture, and the key challenge is to fabricate defect-free selective nanofilms as thin as possible (100 nm or below) with superior CO2/N2 separation performance. Herein, we developed high-performance membranes based on an unusual choice of semi-crystalline blends of amorphous poly(ethylene oxide) (aPEO) and 18-crown-6 (C6) using two nanoengineering strategies. First, the crystallinity of the nanofilms decreases with decreasing thickness and completely disappears at 500 nm or below because of the thickness confinement. Second, polydimethylsiloxane is chosen as the gutter layer between the porous support and selective layer, and its surface is modified with bio-adhesive polydopamine (<10 nm) with an affinity toward aPEO, enabling the formation of the thin, defect-free, amorphous aPEO/C6 layer. For example, a 110 nm film containing 40 mass % C6 in aPEO exhibits CO2 permeability of 900 Barrer (much higher than a thick film with 420 Barrer), rendering a membrane with a CO2 permeance of 2200 GPU and CO2/N2 selectivity of 27 at 35 °C, surpassing Robeson's upper bound. This work shows that engineering at the nanoscale plays an important role in designing high-performance membranes for practical separations.

Simultaneous design and operational optimization for flexible carbon capture process using ionic liquids

Carbon capture and storage is an effective way to abate CO2 emissions during the transition to zero-carbon power generation technologies. As renewable electricity sources such as wind and solar photovoltaics become more prevalent, conventional power generation systems are increasingly required to operate at highly variable rates in order to balance intermittent renewable power supply. As a result, post-combustion carbon capture systems integrated with fossil fuel power plants must also operate at variable load. In addition, the solvent regeneration and CO2 compression in capture plants requires substantial amounts of energy and such flexible operation can present an opportunity for operators to take advantage of fluctuating electricity prices, potentially offsetting the cost of carbon capture. This can be achieved through, among others, variable capture rates and utilization of solvent storage. In this paper, we consider a carbon capture system using ionic liquids as a chemical absorption solvent. We study the optimal flexible operation of this system when connected to a natural gas combined cycle power plant under high variable renewable power generation rates. The results show significant cost savings relative to the case of inflexible capture system operation.

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.

Enhancing the post-combustion carbon dioxide carbon capture plant performance by setpoints optimization of the decentralized multi-loop and cascade control system

Enhancing the post-combustion carbon dioxide carbon capture plant performance by setpoints optimization of the decentralized multi-loop and cascade control system

Modeling and Simulation of CO2 Capture Unit using Mixed Solvent of Aqueous Methyldiethanolamine and Piperazine for 6.4 MWe Power Plant

Carbon dioxide emissions are the largest greenhouse gases contributor, which is attributed to global warming. Therefore, the capture of CO2 is necessary, especially from large point sources. Post-combustion capture using chemical solvents is the most matured capture technology. In this paper, mixed solvents of methyldiethanolamine (MDEA) and piperazine (PZ) were studied to potentially address some issues related to the use of conventional monoethanolamine (MEA). Steady-state modeling and simulation of the post-combustion carbon capture using the mixed solvents for a typical 6.4 MWe power plant were done. The model developed was validated against experimented data with relative error between 1 – 4.73% for the absorber on CO2 capture efficiency and between 2.93 – 10.2% relative errors on CO2 regeneration efficiency. The model was scaled up to capture CO2 from the flue gas of a typical 6.4 MWe power plant. The scaled-up results showed packing height and diameter of absorber to be 5.5 m and 1.5 m; while that of the stripper was 5.08 m and 1.45 m respectively. Effect of flue gas temperature on the capture efficiency was studied, it was observed that as the temperature increased from 20 ºC, the capture efficiency increased, but at 70 ºC, the efficiency showed no significant increase which could be associated with the existence of a temperature bulge. Capture efficiency increases with an increase in PZ concentration due to increase in the rate of reaction with concentration. The absorption and regeneration results suggest that an aqueous MDEA/PZ blend could be a prospective absorbent for CO2 capture.

The Application of Biochar for CO2 Capture: Influence of Biochar Preparation and CO2 Capture Reactors.

This work investigates three types of biochar (bamboo charcoal, wood pellet, and coconut shell) for postcombustion carbon capture. Each biochar is structurally modified through physical (H2O, CO2) and chemical (ZnCl2, KOH, H3PO4) activation to improve carbon capture performance. Three methods (CO2 adsorption isotherms, CO2 fixed-bed adsorption, and thermogravimetric analysis) are used to determine the CO2 adsorption capacity. The results show that a more than 2.35 mmol·g-1 (1 bar, 298 K) CO2 capture capacity was achieved using the activated biochar samples. It is also demonstrated that the CO2 capture performance by biochar depends on multiple surface and textural properties. A high surface area and pore volume of biochar resulted in an enhanced CO2 capture capacity. Furthermore, the O*/C ratio and pore width show a negative correlation with the CO2 capture capacity of biochars.

Carbon capture from humid gases using alkaline-promoted polypyrrole by a vacuum swing adsorption process

Post-combustion carbon capture from humid flue gas is one of the urgent research projects for achieving the target of carbon neutrality in near future. Nitrogen-containing polymers are considered as a promising adsorbent for carbon capture in flue gases due to their potential water resistance. Here, two-step synthesis of alkaline-promoted polypyrrole (AP-PPy) with water resistance was investigated as an adsorption material for carbon capture and separation. It was found from chemical and physical analysis that the alkaline-promoted sample kept the similar morphological structure as the pristine polypyrrole but possessed more amino groups. The adsorption of single component gases revealed that the adsorption amounts of CO2, CH4, and N2 were 1.31, 0.28 and 0.065 mmol/g at 303 K respectively, among which the CO2 uptake was 80% higher compared with the original polypyrrole. The breakthrough point of AP-PPy in moisture is comparable to that of dry mixture, but the dynamic CO2 adsorption capacity is calculated to be larger than that of dry condition. A single-bed three-step vacuum swing adsorption cycling device was constructed in the laboratory and the effect of adsorption time, vacuum pressure and feed flowrate on product purity and recovery were explored with over 50 cycles in each condition to ensure cyclic steady adsorption, thereby also verifying the recyclability of AP-PPy. The excellent CO2 adsorption and separation properties demonstrated that AP-PPy can be a promising material for post combustion carbon capture.

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.

Boosting membranes for CO2 capture toward industrial decarbonization

Membrane technology for carbon capture is becoming increasingly attractive to combat the excessive greenhouse gas emitted into the atmosphere, which involves the benefits of cost-effectiveness, environmental-friendly, easy scalability, high energy efficiency, simplicity in design, etc. However, most state-of-the-art membrane materials suffer from either low CO2 permeability, low selectivity towards CO2 separation, poor resistance to plasticization, or inadequate long-term stability, rendering it still challenging to be upscaled to an industrial level. Therefore, the development of advanced membrane materials as well as a reasonable design of the membrane separation process is crucial and urgent for its real-life application in the future. This account reviews the details of some recent research progress in our group on carbon capture from different scenarios including post-combustion carbon capture, biogas upgrading and natural gas sweetening and hydrogen purification. Notably, considerable efforts have been invested in the development of some novel membrane materials in our group, such as facilitated transport membranes, carbon molecular sieving membranes, mixed matrix membranes, composite membranes, and poly(ionic liquids)-based membranes. Meanwhile, some studies focusing on the techno-economic feasibility analysis of membrane technology have also demonstrated its promising application on practical carbon capture.