Post-combustion CO2 Capture Research Articles

Separation of CO2/N2 in Ion-Exchange binder-free beads of zeolite NaY for Post-Combustion CO2 capture

Ion-exchange on bare commercial zeolites can offer improved adsorption processes. In the context of CO2/N2 separation for post-combustion CO2 capture (PCC), here, we report, the effect of ion-exchange on commercial binder-free NaY zeolite with alkali (K+) and alkaline earth (Ca2+) metal cations, achieving exchange levels of 23 %, 58 %, and 95 % for K+ and 56 % and 71 % for Ca2+. Adsorption isotherms of CO2 and N2 were measured over a temperature range of 306–344 K and pressures up to 350 kPa. At low pressures, the CO2 adsorption capacity increases as Na+ ions are exchanged to a higher level of K+, while a reverse trend is observed for Ca2+ exchange. At 25 kPa and 306 K, the CO2 loading (mol∙kg−1) follows the order 2.01-Ca(71)Y < 2.63-Ca(56)Y < 4.05-NaY < 4.29-K(23)Y < 4.59-K(58)Y < 4.72-K(95)Y. The selectivities of CO2 (15 %)/N2 (85 %) at 306 K and 101.3 kPa range from 52 for Ca(71)Y to 101 for K(23)Y, compared to 89 in the bare NaY zeolite. The working capacities for the most promising exchanged sample (K(23)Y) exhibit superior values of 4.51, 2.98, and 2.41 mol∙kg−1 considering regeneration pressures of 3, 10, and 15 kPa, relative to a feed pressure of 101.3 kPa, respectively. Dynamic simulations were conducted using the Aspen Adsorption package to accurately predict both single- and binary-component breakthrough curves.

Insights into Aerosol Emission Control in the Postcombustion CO2 Capture Process: From Cluster Formation to Aerosol Growth.

Aerosols produced in the amine carbon capture process can lead to secondary environmental pollution. This study employs molecular dynamics (MD) simulations to investigate cluster formation, amine behavior, and aerosol growth of amines, essential for reducing amine aerosol emissions. Results showed that the cluster evolution process can be divided into cluster formation and growth in terms of molecular content, and the nucleation rate for the present systems was estimated in the order of 1028 cm-3 s-1. CO2 absorption was observed alongside successful nucleation, with CO2 predominantly localizing in the cluster's outer layer postabsorption. Monoethanolamine (MEA) exhibited robust electrostatic interactions with other components via hydrogen bonding, leading to its migration toward regions where CO2 and H2O coexisted within the cluster. While MEA presence markedly spurred cluster formation, its concentration had a marginal effect on the final cluster size. Elevating water content can augment the aerosol growth rate. However, altering the gas saturation is possible only within narrow confines by introducing vapor. Contrarily, gas cooling introduced dual, opposing effects on aerosol growth. These findings, including diffusion coefficients and growth rates, enhance theoretical frameworks for predicting aerosol formation in absorbers, aiding in mitigating environmental impacts of amine-based carbon capture.

Resembling Graphene/Polymer Aerogel Morphology for Advancing the CO2/N2 Selectivity of the Postcombustion CO2 Capture Process.

The separation of CO2 from N2 remains a highly challenging task in postcombustion CO2 capture processes, primarily due to the relatively low CO2 content (3-15%) compared to that of N2 (70%). This challenge is particularly prominent for carbon-based adsorbents that exhibit relatively low selectivity. In this study, we present a successfully implemented strategy to enhance the selectivity of composite aerogels made of reduced graphene oxide (rGO) and functionalized polymer particles. Considering that the CO2/N2 selectivity of the aerogels is affected on the one hand by the surface chemistry (offering more sites for CO2 capture) and fine-tuned microporosity (offering molecular sieve effect), both of these parameters were affected in situ during the synthesis process. The resulting aerogels exhibit improved CO2 adsorption capacity and a significant reduction in N2 adsorption at a temperature of 25 °C and 1 atm, leading to a more than 10-fold increase in selectivity compared to the reference material. This achievement represents the highest selectivity reported thus far for carbon-based adsorbents. Detailed characterization of the aerogel surfaces has revealed an increase in the quantity of surface oxygen functional groups, as well as an augmentation in the fractions of micropores (<2 nm) and small mesopores (<5 nm) as a result of the modified synthesis methodology. Additionally, it was found that the surface morphology of the aerogels has undergone important changes. The reference materials feature a surface rich in curved wrinkles with an approximate diameter of 100 nm, resulting in a selectivity range of 50-100. In contrast, the novel aerogels exhibit a higher degree of oxidation, rendering them stiffer and less elastic, resembling crumpled paper morphology. This transformation, along with the improved functionalization and augmented microporosity in the altered aerogels, has rendered the aerogels almost completely N2-phobic, with selectivity values ranging from 470 to 621. This finding provides experimental evidence for the theoretically predicted relationship between the elasticity of graphene-based adsorbents and their CO2/N2 selectivity performance. It introduces a new perspective on the issue of N2-phobicity. The outstanding performance achieved, including a CO2 adsorption capacity of nearly 2 mmol/g and the highest selectivity of 620, positions these composites as highly promising materials in the field of carbon capture and sequestration (CCS) postcombustion technology.

Tetrameric self-assembling of water-lean solvents enables carbamate anhydride-based CO2 capture chemistry

Carbon capture, utilization and storage is a key yet cost-intensive technology for the fight against climate change. Single-component water-lean solvents have emerged as promising materials for post-combustion CO2 capture, but little is known regarding their mechanism of action. Here we present a combined experimental and modelling study of single-component water-lean solvents, and we find that CO2 capture is accompanied by the self-assembly of reverse-micelle-like tetrameric clusters in solution. This spontaneous aggregation leads to stepwise cooperative capture phenomena with highly contrasting mechanistic and thermodynamic features. The emergence of well-defined supramolecular architectures displaying a hydrogen-bonded internal core, reminiscent of enzymatic active sites, enables the formation of CO2-containing molecular species such as carbamic acid, carbamic anhydride and alkoxy carbamic anhydrides. This system extends the scope of adducts and mechanisms observed during carbon capture. It opens the way to materials with a higher CO2 storage capacity and provides a means for carbamates to potentially act as initiators for future oligomerization or polymerization of CO2.

Microwave pyrolysis of waste biomass and synthesis of micro-mesoporous activated carbons: The role of textural properties for CO2 and textile dye adsorption

Hierarchical porous activated carbons (ACs) were efficiently synthesized in less than 2 min using microwaves and phosphoric acid (H3PO4), exhibiting excellent potential as adsorbent for carbon dioxide (CO2) and Methylene Blue (MB). The method emphasizes the development of selective physicochemical and textural properties crucial for CO2 post-combustion capture and textile dye removal from water, using agricultural waste as carbon precursor to address the environmental and economic challenges associated with the preparation of ACs. Dielectric properties confirmed H3PO4 increased the microwave absorption properties of the biomass. Employing a single-step method, the resulting ACs exhibited large specific surface areas exceeding 1000 m2g−1, achieved in less than 2 min and relatively low energies (2.4 GJ ton-1). Sample 0.4H4 displayed a surface area of 1145 m2g−1 and a significant ultra-micropore (<0.7 nm) content, demonstrating a CO2 uptake of 4.1 and 2.8 mmolg−1 at 0 and 25 °C, with high CO2/N2 selectivity (>38). The sample exhibited rapid CO2 uptake in 5 min and efficient regeneration after 20 adsorption–desorption cycles. Sample 0.3H3 developed large mesoporosity and a high surface area of 1217 m2g−1 with less than 3 min of treatment. The maximum dye removal was 281 mgg−1 and adsorption mechanisms involved diffusion into the mesoporous matrix, electrostatic interactions, H-bonding between AC and MB acid groups, and π–π interactions. The experimental data best fitted the Freundlich model. The results confirmed that microwaves have the potential to convert waste to micro-mesoporous ACs that can be used for a wide range of applications with significant processing time reductions and superior product qualities compared to conventional technologies.

Optimizing alkaline solvent regeneration through bipolar membrane electrodialysis for carbon capture

This work demonstrates and characterizes the use of a bipolar membrane electrodialysis for pH-driven CO2 capture and solvent regeneration using potassium hydroxide solutions. The impact of potassium concentration, current density and load ratio on the CO2 desorption efficiency was analyzed and substantiated with an equilibrium model. The system was tested with partially saturated solutions that mimic the expected carbon content of alkaline solvents that have been in contact with flue gas (carbon loading of 0.6 and K+ concentration from 0.5 M to 2 M). Among the tested current densities, 1000 A/m2 demonstrated the highest CO2 desorption efficiency but also the highest energy consumption, whereas 250 A/m2 exhibited the lowest energy consumption (8.8 GJ/ton CO2) but lower CO2 desorption. Efficiency losses were associated with H+ transport across the membranes at high load ratios and decrease of the bipolar membranes water dissociation efficiency at low current densities. This work establishes key performance indicators and describes fundamental characteristics of continuous bipolar membrane electrodialysis systems for regeneration of alkaline solvents used in post-combustion CO2 capture.

CFD investigation of post-combustion CO2 capture using an industrial spray tower: Regulation effects of spray schemes

The use of spray towers for post-combustion CO2 capture has attracted growing industrial interest. However, its practical application is hampered by a lack of knowledge about CO2 spray absorption on an industrial scale. Herein, we developed a numerical model to explore the potential of the spray tower for CO2 removal at a 330 MW coal-fired power plant. The model was developed in the Euler-Lagrange framework integrated with interphase transfer models. The variations of gas-droplet flow, CO2 removal efficiency, CO2 loading of rich solution, and temperature distribution under different spray schemes were investigated. It was found that gas flow hydrodynamics and CO2 removal performance can be regulated by the spray scheme. Compared to the conventional downward spray scheme, the lower nozzle layer adopted an upward spray scheme can improve the uniformity of the gas flow and results in several advantages: (1) average droplet residence time is extended by 5.2 %; (2) CO2 removal efficiency increases from 79.1 % to 82.9 %. This improvement is attributed to two factors: one is the droplet’s re-distribution, lowering the gas flow resistance in the region below the first spray layer near the inlet; the other is the change in gas-droplet interaction whereby the upward-moving droplets entrain the gas to flow upwards. Moreover, we investigated the effects of the spray schemes under varying flue gas loads. Under these conditions, the upward spray mode adopted in the first layer shows the best CO2 removal performance. Further theoretical analysis reveals the mechanisms underlying the regulation effect. The findings in this work will benefit the design and optimization of the industrial-scale spray tower for CO2 removal.

Thermodynamic Analysis of Low-Emission Offshore Gas-to-Wire Firing CO2-Rich Natural Gas: Aspects of Carbon Capture and Separation Systems

Despite the growth of renewable energy, fossil fuels dominate the global energy matrix. Due to expanding proved reserves and energy demand, an increase in natural gas power generation is predicted for future decades. Oil reserves from the Brazilian offshore Pre-Salt basin have a high gas-to-oil ratio of CO2-rich associated gas. To deliver this gas to market, high-depth long-distance subsea pipelines are required, making Gas-to-Pipe costly. Since it is easier to transport electricity through long subsea distances, Gas-to-Wire instead of Gas-to-Pipe is a more convenient alternative. Aiming at making offshore Gas-to-Wire thermodynamically efficient without impacting CO2 emissions, this work explores a new concept of an environmentally friendly and thermodynamically efficient Gas-to-Wire process firing CO2-rich natural gas (CO2 &gt; 40%mol) from high-depth offshore oil and gas fields. The proposed process prescribes a natural gas combined cycle, exhaust gas recycling (lowering flue gas flowrate and increasing flue gas CO2 content), CO2 post-combustion capture with aqueous monoethanolamine, and CO2 dehydration with triethylene glycol for enhanced oil recovery. The two main separation processes (post-combustion carbon capture and CO2 dehydration) have peculiarities that were addressed at the light shed by thermodynamic analysis. The overall process provides 534.4 MW of low-emission net power. Second law analysis shows that the thermodynamic efficiency of Gas-to-Wire with carbon capture attains 33.35%. Lost-Work analysis reveals that the natural gas combined cycle sub-system is the main power destruction sink (80.7% Lost-Work), followed by the post-combustion capture sub-system (14% Lost-Work). These units are identified as the ones that deserve to be upgraded to rapidly raise the thermodynamic efficiency of the low-emission Gas-to-Wire process.

Evaluating the performance of carbon-based adsorbents fabricated from renewable biomass precursors for post-combustion CO2 capture

The significant increase in atmospheric CO2 concentration originated mainly from fossil fuels combustion has encouraged the development and improvement of CO2 separation operations to reduce emissions and control climate change and global warming. Therefore, this work is focused on the separation of CO2 from N2 in flue gas streams under post-combustion conditions by developing low-cost adsorbents. Six carbons were fabricated from biomass resources (olive stones and almond shells) to assess their influence on CO2 adsorption capacity: One carbonized and two KOH-activated carbons with carbon/KOH ratio of 1:2 and 1:4 (w/w) for each precursor. The carbons were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), elemental analysis, nitrogen and carbon dioxide adsorption–desorption analysis, X-ray diffraction (XRD), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and point of zero charge determination. In addition, the equilibrium adsorption data of pure components for all adsorbents were measured at 0, 25 and 50 °C between 0 and 760 mmHg and CO2/N2 selectivity was determined. Activated carbons were found to have higher CO2 adsorption capacity but with a reduction in apparent selectivity. Dynamic binary adsorption simulations performed in a fixed-bed column demonstrated that the activated carbon produced from olive stones with a carbon/KOH ratio of 1:4 (w/w) can separate a mixture of 14 % CO2 and 86 % N2 at 25 and 50 °C with the highest selectivity, CO2 adsorption capacity, CO2 purity and N2 recovery factor. Reducing flow rate, the breakthrough time increased. Moreover, the breakthrough time was reduced by increasing the temperature from 25 to 50 °C owing to the exothermic nature of adsorption process.

Measurement of the critical temperatures, pressures, and thermal diffusivities of glymes from monoglyme to tetraglyme

The critical temperatures, critical pressures, and thermal diffusivities have been measured for mono-, di-, tri-, and tetraglymes, compounds that are used for pre- and post-combustion capture of CO2, H2S and other gases. The critical properties have been measured using the pulse-heating method applicable to thermally unstable compounds. The combined relative expanded uncertainties with the 0.95 level of confidence are 0.01 and 0.03 for the critical temperature and pressure, respectively. The acentric factors of the compounds have been calculated based on the experimental data. The critical properties of these compounds have also been calculated by the group contribution methods of Wilson and Jasperson, Nannoolal et al., and Hukkerikar et al. in two variants. The Wilson/Jasperson technique provides the best estimation of the critical temperature and the Hukkerikar et al. one gives the best results for the critical pressure. The thermal diffusivities of glymes have been measured at atmospheric pressure in the temperature range from 303.15 to 353.15 K. The thermal conductivities of glymes have been calculated from the experimental data. The temperature dependence of the thermal diffusivities and thermal conductivities has been approximated by linear polynomials. The experimental thermal conductivities of glymes have been compared with those estimated by the methods of Govender et al. and Liu et al. The method of Govender et al. provides a good estimation of the thermal conductivity of glymes.

Thermal energy storage integration for increased flexibility of a power plant with post-combustion CO2 capture

Flexible operation of thermal power plants will become increasingly relevant in the coming years. This work evaluates the effect of integrating a steam accumulator into a 598 MW supercritical coal-fired power plant with moving bed temperature-swing adsorption CO2 capture. Charging the accumulator with reheat steam from the turbine train can reduce the net power output by up to 1.4 % (8.2 MW) for around 200 min. Small charging flow rates are recommended to maximize the final pressure of the accumulator. Covering the sorbent regeneration duty and meeting the demand of two feedwater heaters were considered as alternatives for discharging of the accumulator. Thermal storage discharging was found to give relative power plant load increases between 1.7 and 11.2 % (10.2–66.9 MW) for up to 37.5 min, which exceeds the requirement for primary reserve. Increases in the electrical energy output of 10.5–11 MWh were achieved. The flexibility modes studied in this work are compatible with high CO2 recovery rates.

Corrosion Behavior of Carbon Steel in Diethylenetriamine Solution for Post-combustion CO2 Capture.

In the realm of postcombustion carbon capture, diethylenetriamine (DETA), recognized for its substantial CO2 absorption capacity, presents a formidable challenge due to its corrosive impact on equipment. This study delves into the corrosion behavior of 20# carbon steel immersed in DETA solutions under varying conditions, employing weight loss and electrochemical methods. The investigation incorporates scanning electron microscopy/energy-dispersive spectroscopy and X-ray diffraction analyses for characterization. Corrosion experiments were also conducted in monoethanolamine (MEA) solutions for a comparative analysis. Results from the corrosion tests in DETA solutions mirror the temperature-dependent corrosion rate (CR) observed in MEA. However, a distinctive trend emerges as the CO2 loading of DETA increases from 0.2 mol CO2/mol amine to 1.2 mol CO2/mol amine, leading to a continuous decrease in the CR of carbon steel-contrary to MEA solutions. This anomaly is attributed to DETA's robust complexing ability with metal ions and its elevated solubility of Fe2+ in solution. Additionally, an examination of the corrosion mechanism in the presence of oxygen was conducted through characterizing the specimen surface and solution precipitates postexperiment. The absence of a protective FeCO3 layer can be attributed to insufficient concentrations of free Fe2+ and CO32- in the solution, failing to achieve the minimum saturation required for protective film formation. The insights gained from studying the corrosion behavior of carbon steel in DETA solutions lay the groundwork for subsequent developments in corrosion inhibitors.

Experimental kinetics and thermodynamics investigation: Chemically activated carbon-enriched monolithic reduced graphene oxide for efficient CO2 capture

In this research, we have developed solid MGOs by self-assembled reduction process of GO at 90 °C with different weight ratios of oxalic acid (1:1, 1:0.500, and 1:0.250). The as-synthesized monoliths were carbonized (at 600 °C) and chemically activated with varying proportions of NaOH (1:1, 1:2, and 1:3). This materials offer the CO2 adsorption effect under dynamic conditions, fast mass transfer, easy handling, and outstanding stability throughout the adsorption-desorption cycle. FE-SEM, and HR-TEM analyses confirmed the porous nature and shape of the adsorbents, while XPS examination revealed the presence of distinct functional groups on the surface of the monolith. By increasing the mass ratios (MGO:NaOH) from 1:1 to 1:2, the surface areas increased by approximately 2.6 times, ranging from 520.8 to 753.9 m2 g⁻1 (surface area of the untreated MGO was 289.2 m2 g⁻1). Consequently, this resulted in a notable enhancement of 2.10 mmol g⁻1 in dynamic CO2 capture capacity. The assessment encompassed the evaluation of production yield, selectivity, regenerability, kinetics, equilibrium isotherm, and isosteric temperatures of adsorption (Qst). The decrease in CO2 capture effectiveness with rising adsorption temperature indicated an exothermic and physisorption process. The regenerability of 99.1 % at 100 °C and excellent cyclic stability with efficient CO2 adsorption make this monolithic adsorbent appropriate for post-combustion CO2 capture. The significant Qst lend support to the heterogeneity of the adsorbent's surface, and the pseudo-second-order kinetic model along with the Freundlich isotherm model emerged as the most fitting. Therefore, the current investigation shows that the carbon-enriched adsorbents enhance the CO2 adsorption capacity. It may be used as a low-cost pretreatment method on an industrial scale before carbon capture.

The use of algae as carbon dioxide absorber in heat production industry

There are approximately 15 million users of system heat in Poland, but unfortunately nearly 70% of the fuel used in heat production is fossil fuel. Therefore, the CO2 emission reduction in the heat production industry is becoming one of the key challenges. City Heat Distribution Enterprise Ltd. in Nowy Sącz (Miejskie Przedsiębiorstwo Energetyki Cieplnej sp. z o.o.) has been conducting a self-financed research and development project entitled The use of algae as carbon dioxide absorbers at MPEC Nowy Sącz. The project deals with postcombustion CO2 capture using Chlorella vulgaris algae. As a result of tests conducted in a 1000 l hermetic container under optimal temperature and light conditions, the recovery of biomass can be performed in weekly cycles, yielding approximately 25 kilograms of biomass per year. Assuming that half of the dry mass of the algae is carbon, it can be said that 240 grams of carbon is bound in one cycle, which, converted to CO2, gives 880 grams of this gas. Our results showed that around 45.8 kilograms of CO2 per year was absorbed. Additionally, it is possible to use waste materials and by-products of technological processes as a nutrient medium for algae

Design and thermo-enviro-economic analyses of an innovative environmentally friendly trigeneration process fueled by biomass feedstock integrated with a post-combustion CO2 capture unit

The utilization of biomass feedstock in the energy system for sustainable production is essential due to its renewable nature and high energy density. However, the primary challenge lies in designing environmentally friendly biomass-use structures. This research introduces a novel trigeneration system that integrates power, cooling, and heat production through biomass combustion to address this issue. As another novelty in system development, the proposed system includes a carbon dioxide capture unit, further enhancing the system. The proposed framework consists of several subsystems: an organic Rankine cycle, an absorption chiller, a carbon dioxide capture cycle utilizing monoethanolamine solvent, a liquefied natural gas regasification unit, and a low-pressure steam production boiler. The newly developed system is modeled using the Aspen HYSYS software and is assessed from thermodynamic, economic, and environmental perspectives. Also, a parametric analysis is conducted to examine the impact of key design parameters on the system’s performance. Based on the study’s findings, it can be observed that the energy and exergy efficiencies amount to 58.4 % and 17.09 %, respectively. In addition, the suggested procedure exhibits a total exergy destruction of 53,636 kW. The findings of the environmental impact assessment indicate that the shift from power generation to trigeneration scenario results in a substantial decrease in carbon dioxide emissions. Specifically, the emission reduction potential ranges from 0.24 to 0.041 kg/kWh. Furthermore, the economic evaluation shows that the system reaches a cost per unit exergy of 0.249 $/kWh. This variable denotes a substantial decrease of 81.42 % compared to the power generation operational mode.

Performance of industrially implemented turbulent contact absorbers – A comparative study

The current study aims to assess the performance and industrial feasibility of using three-phase fluidized bed absorption columns for post-combustion carbon dioxide (CO2) capture. The analysis is based on a mathematical model of a scaled-up fluidized bed absorption column that has been validated using pilot plant experimental data. The focus is on evaluating the energy efficiency of the fluidized bed column in comparison to packed bed technologies, which are currently widely used. The results of the analysis are evaluated in terms of three performance indicators (i.e., absorption efficiency, carbon capture rate, and energy performance index) and compared to packed bed columns. Simulation results indicate that the best column configuration is represented by a three-stage absorber and that the system performs optimally when particle diameter and density decrease with each section. Consequently, this leads to an increase in the total fluidized bed height and carbon capture rate by up to 25%. The energy performance index is maintained below 3.6, indicating an energy-efficient operation of the system. As such, the findings of this study suggest that the use of gas-solid-liquid three-phase fluidized bed absorption columns for post-combustion CO2 capture is a promising technology for the implementation of CCUS and for achieving of climate neutrality targets.

Scaling up 3D printed hybrid sorbents towards (cost) effective post-combustion CO2 capture: A multiscale study

A 3D-printed sorbent containing polyethylene-imine and multi-walled carbon nanotubes (PEI-MWCNT) was studied for post-combustion carbon capture. In this work, the adsorbent was printed on a kg scale and characterized for CO2 adsorption through lab experiments. A 6-step VSA process was simulated using the lab data to capture CO2 from a representative 800 MW power plant. The adsorbent captured >70 % of the CO2 and 95 % CO2 purity was achieved. The levelized cost of electricity (LCOE) was 130.2 $/MWh and the costs of CO2 captured and avoided were 80 and 100.12 $/tonne. However, a zeolite 13X-activated carbon (13X-AC) monolith achieved a lower LCOE of 118.1 $/MWh, with the captured and avoided costs being 63 and 78.4 $/tonne, respectively. The LCOE value for the 13X-AC monolith was 5.1 % lower than a reference-packed bed system with Zeolite 13X pellets. The corresponding cost values were lower by 9.1 % and 13.9 %, respectively for the costs of CO2 captured and avoided. The lab experiments on the PEI-MWCNT sorbent revealed that further work is necessary to improve the thermal stability and stability with long-term storage of the precursor paste.

Biochar-mediated release of CO2 from monoethanolamine/H2O solution with low energy requirement over ZrO2/SiO2/biochar ternary catalysts

CO2 absorption technology based on amine solutions has sustained appeal due to its high efficiency in post-combustion capture of CO2. However, the high energy penalty of solvent regeneration limits its large-scale industrial application. Therefore, designing inexpensive catalysts to reduce solvent regeneration energy consumption remains challenging. This study reports a recyclable ternary catalyst, ZrO2/SiO2/biochar, which was synthesized by co-pyrolysis of zirconium oxychloride and wheat flour in the presence of SiO2 nanoparticles. The incorporation of biochar improved the distribution of Lewis acidic sites (LAS) and Brønsted acidic sites (BAS). The improved BASs and LASs of ZrO2/SiO2/biochar catalyst were conductive to donate protons or accept electrons and thus, the amount and rate of CO2 desorption from CO2-saturated monoethanolamine (90 °C) were more than 24% and 26% higher, respectively, to compare with the catalyst-free system at the same conditions. As a result, the energy penalty was decreased by about 31%. A biochar-mediated proton-transfer mechanism that the presence of biochar increased the mesoporous proportion, the BAS and L/B ratio as well as the favorable charge transfer was inferred for the ZrO2/SiO2/biochar-catalyzed CO2 release through experimental evidence. The results reveal the role of biochar in solid acid catalysts for CO2 desorption, which will provide a novel strategy for building solid acid catalysts to reduce energy requirements in CO2 capture.

Membrane CO2 Separation System Improvement for Coal-Fired Power Plant Integration

Even though there are numerous CO2 capture technologies (such as chemical and physical absorption), investigators are still trying to come up with novel methods that can minimize the energy requirements for their integration into thermal power plants, as well as the CAPEX and OPEX expenses. In this work, the technical and financial aspects of integrating two-stage polymeric membranes into a coal-fired power plant with a capacity of 330 MW were examined. The study researched the membrane post-combustion CO2 capture process utilizing CHEMCAD version 8.1 software with several parameters and an expander to decrease the total cost. The simulation showed promising results regarding reducing power consumption after using an expander for both a high capture rate (&gt;90%) and a CO2 concentration of more than 95%. Thus, the CO2 captured cost decreased from 58.4 EUR/t (no expander) to 48.7 EUR/t (with expander).

Correction: Hasan et al. Synthesizing and Characterizing a Mesoporous Silica Adsorbent for Post-Combustion CO2 Capture in a Fixed-Bed System. Catalysts 2023, 13, 1267

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