This work aims at verifying the CO2 absorption capture model using monoethanolamine (MEA) solvent developed by the U.S. DOE’s Carbon Capture Simulation Initiative (CCSI) and performing uncertainty propagation of mass transfer, liquid hold-up and reaction kinetics properties in the complete model, which includes absorber and stripper columns. The verification of the Aspen Plus CCSI model, based on pilot plant data from the National Carbon Capture Center (NCCC) for a CO2 flue gas concentration between 7 and 11% (mol) allowed uncertainty quantification (UQ) analysis for four different selected operational points using Monte Carlo Simulation (MCS), where low liquid mass transfer parameters exhibited an impact on calculation convergence. Gaussian Processes (GP) surrogate model was implemented, followed by a sensitivity analysis in order to correlate the most sensitive parameters with studied outputs.

Direct air capture (DAC) has recently gained interest as a carbon dioxide removal (CDR) method to reduce atmospheric CO2. DAC is mainly studied through standalone separation technologies, especially adsorption and absorption. Hybrid DAC, combining separation technologies, is rarely investigated and is the main topic of this work. This study investigates hybrid DAC using adsorption for pre-concentration up to a few percent or tens of percent depending on the case studied and membrane separation to concentrate the CO2 stream to high purity (>90%). Adsorption regeneration by temperature swing adsorption (TSA) and vacuum thermal swing adsorption (VTSA) are compared, and VTSA regeneration achieved higher pre-concentration outlet CO2 purity (15–30%) than TSA regeneration (1–10%). Membrane separation is studied depending on inlet CO2 purity and outlet-required purity (90 or 95%), which influence the energy requirement and cost of capture. For all cases studied, the cost of capture remained high (>1700 €/tCO2) with a high energy requirement (>2 MWhe/tCO2 and >27 GJ/tCO2). The adsorption pre-concentration step accounted for the majority (>80%) of the energy requirement and cost of capture, and future work should be focused on preferentially improving adsorption step performance.

This study investigates a direct air capture (DAC) process using a monoethanolamine (MEA) absorption process, further enhanced by the integration of heat pump modifications such as lean vapor compression (LVC) and stripper overhead compression (SOC) in the regeneration stage to reduce reboiler requirement. The process is modeled using Aspen Plus and incorporating the CCSI model adapted and suited for DAC environmental conditions. Technical performance was investigated through a sensitivity analysis of various environmental and process parameters, including MEA emission, air inlet temperature and humidity, and factors such as solvent loading, capture rate, gas velocity, and liquid to gas ratio. A scrubber section above the absorber was installed to mitigate MEA emission. The implementation of LVC and SOC results in a significant reduction in regeneration consumption of 25% compared to conventional MEA-based processes but the cost of capture is similar to that of the conventional process, due to additional capital investment. The regulatory limits on MEA emission at the air outlet have a significant impact on the dimensions of the scrubber section and therefore the overall cost of capture is reduced by 8% for the 6 ppm-mol emission limit in comparison to the 0.1 ppm-mol limit. Detailed techno-economic analyses were performed for design cases with capture scales ranging from 0.1 to 1 MtCO2/yr, with capture costs ranging from 1091 to 1283 /tCO2.

This article investigates the performance of Faradaic electro-swing reactive adsorption (ESA) for CO2 capture using simulations. Traditional methods such as amine scrubbing face energy efficiency challenges, particularly at low CO2 concentrations. ESA, which uses electricity for CO2 regeneration, offers a promising alternative due to its isothermal operation and scalability. The study models ESA using quinone-based redox-active CO2 carriers in an electrochemical cell with an ionic liquid electrolyte, allowing reversible adsorption and release through voltage control. The model estimates system productivity and energy consumption, considering transport and chemical kinetics. Key findings show that operating parameters, such as applied potential and gas flow rate, have a significant effect on efficiency. Applying a potential of −1.3 V improved the adsorption capacity, reducing CO2 capture time compared to −1.1 V. At a 1% CO2 concentration and a low flow rate, effective capture resulted in a productivity of 1.6 kg/(m3·day) with an energy consumption of 0.6 MWh/tCO2. However, higher gas flow rates reduced capture efficiency due to CO2 transport limitations in the ionic liquid. Optimization of electrode design is essential to improve ESA efficiency.

This study investigates a direct air capture (DAC) process using a solid-DAC S-VTSA (steam-assisted vacuum thermal swing adsorption) process. A commercially available sorbent, commonly used in packed bed configurations, is selected as the benchmark sorbent, while a monolithic geometry is also examined to assess its potential performance. The process is modelled using Aspen Adsorption and incorporates physico-chemical data in DAC environmental conditions, including binary isotherms under humid condition. In a reference case comparing the two geometries, the packed bed exhibits higher productivity (2.4 kgCO2/(h.m3)), while the monolith achieves 1.2 kgCO2/(h.m3). However, the monolith allows for a significant reduction in pressure drop and associated fan work by about two orders of magnitude. These findings highlight the trade-off between productivity in favor of packed bed and energy requirement in favor of monolithic design. A sensitivity analysis is then conducted on various environmental and process parameters such as sorbent and bed dimension, air velocity, temperature and humidity, adsorption/desorption loading, mass transfer kinetic, and regeneration pressure, temperature, and steam flowrate. Detailed techno-economic analysis, using Aspen Process Economic Analyzer software for capital cost estimation, is performed at capture scale of 100 ktCO2/yr, with capture costs higher than 1500 €/tCO2.

The necessity to mitigate global warming has intensified research into efficient CO2 capture processes, which are of crucial importance to the carbon capture, utilization, and storage (CCUS) industry. Chemical absorption, particularly using aqueous amine blends, has emerged as a mature technology for post-combustion carbon capture due to its efficiency, energy requirements, and operational stability. This study aims to enhance the thermodynamic modelling of the CO2-PZ-MDEA-H2O system in Aspen Plus V12.1 software, employing ELECNRTL and ENRTL-RK models. The initial data collection and analysis involved 952 literature sources to optimize model’s thermodynamic parameters using the Maximum Likelihood method, resulting in significant accuracy improvements of 34% and 68% for ELECNRTL and ENRTL-RK, respectively. The process models were validated against data from the EDF pilot plant in Le Havre demonstrating their efficacy in simulating CO2 capture processes. Furthermore, simulations within Aspen Plus were conducted to evaluate the performance of various packing types, liquid holdup correlations, mass transfer models, and flow configurations. This was deemed crucial for process and column design. The study also investigated the use of AMP-PZ blends, which had been previously validated by NETL at another European pilot plant, to determine their potential for CO2 capture applications. While AMP-PZ solvent requires a lower liquid-gas ratio than MDEA-PZ for CO₂ capture, it consumes more heat; increasing solvent concentration and using flue gas recirculation reduces heat demand, but capturing over 99% CO₂ significantly increases heat consumption due to the need for very low lean solvent loading.

This study applies the Morris method for a sensitivity analysis to evaluate the input parameters’ influence on the heat release rate in a pyrolysis model, focusing on two materials, poly(methyl methacrylate) (non-charring) and poly(vinyl chloride) (charring), examined under a cone calorimeter. A key aspect of our exploration was the role of input parameter variation intervals on the sensitivity outcomes. We analyzed three interval-setting methods: 1. A standard ±10% deviation from the nominal value, commonly used in the literature. 2. A range determined by the experimental uncertainties for individual parameters. 3. A span from minimum to maximum values found in existing literature for each parameter. Our intensive literature review supported the framing of intervals for the latter two methods. Our findings underscore the critical role of the selected variation interval. Specifically, while a uniform ±10% variation identified activation energies as the primary influencers—consistent with prior literature—the introduction of experimental uncertainties shifted this prominence toward heats of reaction. Thus, the selected interval can drastically reshape the perceived importance of certain parameters. This original work challenges the traditionally employed variation ranges in sensitivity studies, emphasizing the need for a nuanced approach.

This work exploits photogrammetry techniques to make real-time measurements on a deforming material subjected to an external heat flux. Using a novel bench design and 3D reconstruction associated to image analysis, the volume of the sample can be accurately calculated. It is applied to a fire retarded polymer (ethylene-vinyl acetate copolymer containing 65 wt% of aluminum trihydroxide as fire retardant). The material shrinks and swells upon heating (heat flux of 35 kW/m2). The volume can be followed as a function of time and it provides quantitative data about the deformation of the material.

Carbon capture and storage using chemical absorption is a viable method for reducing CO2 emissions from the industrial sector. Thermodynamic analysis of MDEA-PZ aqueous alkanolamine solution is of paramount importance to better simulate and improve the efficiency of CO2 capture processes. In this study, we use the Aspen Plus simulator (V12.1) to compare the theoretical differences and the regression results of the two-liquid activity coefficient models ELECNRTL and ENRTL-RK in terms of CO2 solubility. The quaternary system CO2-MDEA-PZ-H2O vapor-liquid equilibrium (VLE) data found in the open literature are first collected. After excluding anomalous points according to some criteria, 521 confirmed data ranging from 40 °C to 120 °C are then used to regress the binary interaction parameters of molecule-molecule and molecule-electrolyte pairs for both models using the maximum likelihood method. The fitting results show an accuracy enhancement of 34 % for ELECNRTL and 68 % for ENRTL-RK compared to the Aspen default models. The regressed models can be used to improve the accuracy of absorber and stripper simulations in CO2 capture processes.

Modelling the swelling behaviour of intumescent materials is an important and challenging issue because this phenomenon influences their pyrolysis process. It must be therefore considered to improve the predictability of pyrolysis models. The objective of this work was to implement a swelling model in the pyrolysis code Gpyro in order to predict the behaviour of a sample of ethylene vinyl acetate containing aluminium trihydroxide (EVA/ATH) polymer studied by cone calorimetry. This polymer is used for making the external sheath of electrical cables. Unlike existing works in the literature, the model implemented here, and adapted to EVA/ATH, does not require information on the densities of the initial and final materials, which makes it more predictive. To characterize the swelling, experiments were carried out to measure the evolution of the sample thickness as a function of time. The mass loss and the back surface temperature of the sample were also measured. This was done under different operating conditions. These measurements are compared with the swelling predicted by the model and the results were found to be in good agreement. The model can be extended easily to other materials.

A working group including Aluminium Dunkerque, Trimet, Rio Tinto and Fives collaborated with EDF to perform a preliminary feasibility study for a CO2 capture unit aiming at decarbonising primary aluminium smelters. The study focuses on the conventional MEA-based absorption capture process with the objective to adapt such process to the aluminum production technical challenges, namely the exhaust gases composition (~1%v. CO2, ~20%v. O2 and minor amounts of SOX, CO, HF and dusts) and the on-site integration (thermal integration, site associated footprint). The study considers aluminium smelters from Dunkirk, France (Aluminium Dunkerque) as the application case with the objective to capture at least 60% of CO2 direct emissions produced the production site (~400 kt of CO2 per year). EDF has worked in close cooperation with the working group to identify the optimal CO2 capture configuration between several study cases: the reference one with 1%v. CO2 and other cases involving CO2 preconcentration up to 5%v. in the flue by modifications of existing electrolysis cells. The study also includes the thermal integration within the production site in order to produce low-quality steam for amine regeneration. The technical and economic assessment was performed through the process modelling and sizing using the Aspen Plus software and a cost estimation (CAPEX, OPEX and CO2 capture costs) using Aspen Process Economic Analyzer, EDF’s internal database and suppliers consultations. This feasibility study has not highlighted any specific critical gaps for integration of a chemical absorption capture process in the aluminium production site. Among the investigated configurations, a CO2 preconcentration through electrolysis cells modification allows the most competitive capture costs (30-40% capture cost reduction in comparison to the reference case). In complement, the working group has performed a complete costs assessment of CO2 capture integration on the production site (including electrolysis cells modification, flue gas desulfurization unit, water treatment basin as well as the utilities supply) but these results are not discussed here. In any cases, total estimated CO2 capture costs remain higher than the projected cost per ton of carbon in the EU-ETS market and will not be competitive without major public funding. In addition, the development of new technologies, specifically adapted to the aluminum sector challenges, appears essential in order to significantly reduce capture costs for the aluminium production.

A sensitivity analysis is performed using the Morris method to prioritize the input parameters of a pyrolysis model according to their degree of influence on the heat release rate (HRR). Moreover, this sensitivity analysis aims determining possible interactions between the input parameters. Indeed, this important aspect is original and at our best knowledge has never been studied in the past. Two materials are studied under cone calorimeter: a non-charring (poly(methyl methacrylate) (PMMA)) and a charring one (polyvinyl chloride (PVC)). Different thicknesses and external heat fluxes are studied to determine their effects on the parameters influence. With regard to PMMA, the most influent parameters are the activation energy, the emissivity, the density and the heat capacity. For the PVC, the most influent parameters are the activation energies. For the PVC, this study showed the existence of interactions between input parameters. This result is original and shows the importance of considering this in sensitivity analysis studies.

CO2 capture processes are part of the decarbonation solutions being considered to reduce direct CO2 emissions from the power and industrial sectors. The process of CO2 capture by chemical absorption in amine-based solvents is the most mature for capturing CO2 in flue gases and well suited to large single sources of CO2. Most of the reference studies have been performed with a capture rate of 90% but recent techno-economic studies have been carried out with a higher capture rate up to 99% to achieve in-depth decarbonation. The aim of this study is to evaluate the techno-economic effect of the capture rate using a class 5 estimation based on relevant orders of magnitude. It is here applied to the capture of CO2 in the flue gas of several industrial sectors: electric power using coal and gas but also hydrogen production by steam reforming, cement, and steel. The cost estimate for CO2 capture in coal-fired power plants is in accordance with the different class 4 estimates in literature for an extended capture rate (0-99%). For a capture rate of 99%, the increase in power generation cost is about 8 to 15% compared to the costs at 90% capture rate. Similar trends are obtained in natural gas combined cycle plants. In addition to the power sector, the application of CO2 capture to produce hydrogen by steam reforming and cement shows an increase of 10% and 20% respectively in the production cost for a capture rate of 99% compared to 90%. The application for steel production highlights the complexity of an integrated hot rolled steel production unit, which limits the implementation of CO2 capture to some of the main blocks. By increasing the capture rate to 99% at the chemical absorption column scale, the capture rate of the production unit could reach 66%, with an increase in production cost by a factor of 1.1.

Electrical cable sheaths are the most abundant fire load in nuclear power plants, mainly in rooms that are kept in under slight pressure. This configuration leads fires to grow in under-ventilated and vitiated conditions. Assessing fire threat involves characterizing the heat released, responsible for fire growth, and the smoke evolved, which may interact with sensitive components in the area. For that purpose, a revisited controlled-atmosphere cone calorimeter has been designed, set up, and coupled to a Fourier transformed infrared spectrometer and an electrical low-pressure impactor to measure simultaneously the evolved gases and aerosols, respectively. This bench-scale apparatus has been first qualified with polymethylmethacrylate. It has second been used to characterize polyvinylchloride cable sheath representative material reaction to fire in under-ventilated and vitiated conditions. It appeared that vitiation in under-ventilated fires lowers the heat release rate and the fuel mass loss rate.

The paper evaluates the performance of an adsorption-based technology for CO2 capture directly from the air at the industrial scale. The approach is based on detailed mass and energy balance dynamic modeling of the vacuum temperature swing adsorption (VTSA) process in Aspen Adsorption software. The first step of the approach aims to validate the modeling thanks to published experimental data for a lab-scale bed module in terms of mass transfer and energy performance on a packed bed using amine-functionalized material. A parametric study on the main operating conditions, i.e., air velocity, air relative moisture, air temperature, and CO2 capture rate, is undertaken to assess the global performance and energy consumption. A method of up-scaling the lab-scale bed module to industrial module is exposed and mass transfer and energy performances of the industrial module are provided. The scale up from lab scale to the industrial size is conservative in terms of thermal energy consumption while the electrical consumption is very sensitive to the bed design. Further study related to the engineering solutions available to reach high global gas velocity are required. This could be offered by monolith-shape adsorbents.

Cet article traite de l’estimation technico-economique d’innovations dans le domaine des procedes de transformation de la matiere et de conversion de l’energie. Les procedes innovants etant par nature non deployes a l’echelle industrielle, la difficulte est d’evaluer une technologie qui n’existe pas encore industriellement, et de le faire avec peu d’informations techniques disponibles. Une demarche pour aborder ce type d’estimation est proposee ici, en considerant l’evaluation des equipements singuliers ainsi que les incertitudes liees a la faible maturite technologique du procede et aux classes d’hypotheses considerees selon les phases d’un projet industriel.

Oxyfuel combustion represents one way for cleaner energy production using coal as combustible. The comparison between the oxycombustion and the conventional air combustion process starts with the investigation of the pyrolysis step. The aim of this contribution is to evaluate the impact of N 2 (for conventional air combustion) and CO 2 (for oxy-fuel combustion) atmospheres during pyrolysis of three different coals. The experiments are conducted in a drop tube furnace over a wide temperature range 800–1400 °C and for residence time ranging between 0.2 and 1.2 s. Coal devolatilized in N 2 and CO 2 atmospheres at low temperatures (< 1200 °C) provides similar results regarding mass loss, char combustion in thermogravimetric analysis and CO concentration. At higher temperatures (> 1200 °C) and longer residence times (> 0.5 s), the char-CO 2 reaction is clearly observed, whose intensity depends on the nature of the coal. Furthermore, the volatile yields are simulated using Kobayashi’s scheme and kinetic parameters are predicted for each coal. The char gasification under CO 2 is also accounted for by the model.