Method For CO2 Capture Research Articles

Thermodynamic exploration of two-stage vacuum-pressure swing adsorption for carbon dioxide capture

Adsorption technology is recognised as a promising CO2 capture method due to its characteristics of low regeneration temperature. Analysis model based on carbon pump concept could be used to reveal thermal performance of various carbon capture technologies. However, the concept still has a large gap to become a comprehensive theory. This paper aims to evaluate thermodynamic performance of two-stage vacuum-pressure swing adsorption (VPSA) from a new definition of single-stage VPSA cycle. Energy consumption and exergy efficiency of VPSA cycles are evaluated and compared. Results indicate that introduction of the second stage can significantly elevate the concentration of product gas with less energy input increase. Also, energy consumption decreases from 114.53 kJ mol−1 to 28.23 kJ mol−1 when initial concentration of CO2 rises from 15% to 75%. However, there is a maximum value of exergy efficiency, 7.01% when initial concentration is 45%. Non-discharged CO2 molecules remained in the void of bed after evacuation process will significantly influence the concentration of product gas. The final concentration of product gas achieves the minimum of 91.90% when concentration differences are both 10% at two stages. One remarkable fact is that a new definition of VPSA cycle may be more feasible for thermal analysis in real applications.

Pseudo counter-current turbulent fluidized bed process with sensible heat recovery for energy-efficient CO2 capture using an amine-functionalized solid sorbent

A fluidized bed adsorption (FLBA) process with internal heat integration is considered an energy-efficient method for large-scale CO2 capture. Herein, we propose a pseudo counter-current FLBA process for post-combustion CO2 capture as a proof-of-concept based on a rationally designed moving bed heat exchanger by incorporating the internal heat integration concept of the conventional amine scrubbing CO2 capture process. The proposed FLBA process consists of an adsorption bed, desorption bed, and moving bed heat exchangers for cooling and heating the solid sorbent. The design of the proposed FLBA process enables internal heat integration by recovering sensible heat from the cooling process. Furthermore, by installing multiple adsorption processes, the pseudo counter-current operation in the adsorption bed enhances the CO2 cyclic capacity of the amine-functionalized solid sorbent with high CO2 recovery. The proposed process complements the two weaknesses of FLBA, namely, large sensible heat and low cyclic capacity of the sorbent. The energy analysis, based on rigorous mathematical modeling, estimates that the energy demand of the optimized FLBA using SiO2/0.37 EB-PEI is approximately 258.6 kWh/t-CO2 with 45% sensible heat recovery. This low energy demand is comparable to that of the most mature amine-based absorption process (271 kWh/t-CO2) owing to the effect of internal heat integration, supporting the feasibility of the FLBA process for post-combustion CO2 capture.

Technical and economic perspectives of hydrate-based carbon dioxide capture

Carbon capture and storage (CCS) is vital for reducing CO2 emissions and achieving climate change targets. Despite proven technical viability, the high cost of current CO2 capture methods hinders widespread applications of CCS. Hydrate-based carbon capture (HBCC) is a promising route for energy-efficient CO2 capture. With an estimated cost of 20 – 40 US$/tonnes of CO2 avoided and an energy penalty of 15%, HBCC is potentially competitive compared to the current capture via conventional absorption (40 – 100 US$/tonnes of CO2 avoided and energy penalty of 30%). HBCC has a competitive edge at industrial scales owing to several intrinsic advantages: (i) a water-based process, (ii) tolerance to impurities in the feed gas, and (iii) potential energy savings via integrating hydrate formation/dissociation enthalpies. However, slow kinetics and limited industrial experience are current challenges to deployment. All these advantages, challenges, and prospects are critically discussed to provide insightful assessments of the techno-economic feasibility of HBCC in comparison to other existing and emerging methods.

Synthesis of MgO nanostructures through simple hydrogen peroxide treatment for carbon capture

The acceleration of global warming induced by uncontrolled CO2 emission has placed a potential threat to human survival and development. The unique properties of magnesium oxide (MgO) including having appropriate surface basicity, low regeneration temperature and high theoretical CO2 uptake capacity make it a promising adsorbent candidate for CO2 capture. Herein, the development and investigation of structure-activity relationships of MgO nanostructures prepared via simple hydrothermal-calcination synthesis method for CO2 capture were reported in this work. The correlation of structural characteristics and basic site properties of MgO samples were discussed by implementing a variety of analytical technologies including BET, SEM, XRD, TPD, Malvern Mastersizer and XPS. The TPD, XPS analysis as well as Claisen-Schmidt condensation reaction show that the hydrothermal-calcination process strongly reduced crystal size and transformed high, low, and moderate basic sites at different ratios for MgO samples. Particularly, MgO nanostructures with morphology of irregular tiny nanocrystals (down to ~5 nm) prepared from simple hydrogen peroxide (H2O2) treatment on commercial MgO exposed abundant moderate and strong basic sites demonstrated significantly better performance (1.04–1.73 mmol/g in a wide temperature range of 100–300 oC) than commercial MgO for CO2 capture. Recyclability of prepared MgO absorbents was also examined and a simple H2O2 regeneration method was explored. The proper correlation of structural characteristics and basic site properties of MgO samples vs their CO2 capture performance were established.

Microfluidic analysis of seawater-based CO2 capture in an amine solution with nickel nanoparticle catalysts

Post-combustion CO2 capture methods like amine scrubbing are currently being utilized to reduce CO2 emissions from fossil fuel power plants. Aqueous monoethanolamine (MEA) solutions are typically used in these processes due to their high CO2 absorption capacity and rapid reaction rate, but these solutions also produce environmentally harmful toxic wastewater and consume large amounts of freshwater. This research analyzes the effectiveness of seawater-based MEA solutions containing nickel nanoparticles (NiNPs) as catalysts, with the goal to minimize the amount of MEA required in the amine scrubbing process and eliminate the use of freshwater. This study is the first to use natural seawater solutions as an alternative to freshwater solutions for CO2 capture. In a microfluidic environment, CO2 microbubbles were generated and their change in size with respect to time was observed to determine the CO2 absorption capacity and rate of the test solutions. Pure seawater demonstrated comparable CO2 absorption to deionized (DI) water. Seawater-based amine solutions absorbed merely 1.79 % less CO2 than DI water-based amine solutions. Seawater-based amine solutions demonstrated faster CO2 absorption rates than their freshwater counterparts. Lastly, to further optimize CO2 absorption, NiNPs were added to each test solution. Seawater with MEA and NiNPs absorbed only 1.15 % less than its DI water counterpart, confirming seawater’s potential as amine-based solvent for industrial CO2 capture applications.

A Comprehensive Study of CO2 Absorption and Desorption by Choline-Chloride/Levulinic-Acid-Based Deep Eutectic Solvents.

Amine absorption (or amine scrubbing) is currently the most established method for CO2 capture; however, it has environmental shortcomings and is energy-intensive. Deep eutectic solvents (DESs) are an interesting alternative to conventional amines. Due to their biodegradability, lower toxicity and lower prices, DESs are considered to be “more benign” absorbents for CO2 capture than ionic liquids. In this work, the CO2 absorption capacity of choline-chloride/levulinic-acid-based (ChCl:LvAc) DESs was measured at different temperatures, pressures and stirring speeds using a vapour–liquid equilibrium rig. DES regeneration was performed using a heat treatment method. The DES compositions studied had ChCl:LvAc molar ratios of 1:2 and 1:3 and water contents of 0, 2.5 and 5 mol%. The experimental results showed that the CO2 absorption capacity of the ChCl:LvAc DESs is strongly affected by the operating pressure and stirring speed, moderately affected by the temperature and minimally affected by the hydrogen bond acceptor (HBA):hydrogen bond donator (HBD) molar ratio as well as water content. Thermodynamic properties for CO2 absorption were calculated from the experimental data. The regeneration of the DESs was performed at different temperatures, with the optimal regeneration temperature estimated to be 80 °C. The DESs exhibited good recyclability and moderate CO2/N2 selectivity.

Carbon dioxide desorption intensified by metal atom

Chemical absorption is an effective method to capture CO2 in industry. The advanced solvent is the key to improve CO2 capture performance. The single atom fluid, containing a single metal atom in a solvent, is developed as a new solvent to reduce the energy consumption. A density functional theory model coupled with fluid flow is developed for the single atom fluid to capture CO2. The experiment is performed to validate the model. According to the model, the effects of temperature, pressure, and weight fraction on CO2 capture performance are studied carefully. It is concluded that the CO2 desorption occurs at 333 K and the mass transfer coefficient is improved up to 17.95%. The film stretch phenomenon is identified, which produces the slag phenomenon by increasing and decreasing of temperature, pressure, and weight fraction to intensify the CO2 capture. The mass transfer coefficient improvement is attributed to thinner film, resulting in mass transfer resistance reduction. The energy consumption is finally reduced to 0.85 GJ/t against the conventional 3.0 to 3.9 GJ/t. This provides an alternative and effective method for CO2 capture.

Green hydrogen and electrical power production through the integration of CO2 capturing from biogas: Process optimization and dynamic control

This study describes the optimization of a modelling process concerning biogas’ use to generate green hydrogen and electrical power. The Aspen Plus simulation tool is used to model the procedure, and the approach employed to limit the emissions of gas from the hydrogen production process will be the CO2 capture method. This technique uses slack lime (Ca(OH)2) to absorb CO2 capture since it is readily available. The study analyzes many critical parameters in the process, including the temperature and pressure in the steam reforming (SR) and the water gas shift (WGS) reactions along with the steam to carbon ratio (S/C) to determine how the production of green hydrogen and electrical power will be influenced. Electricity generation is achieved by taking the residual water from the SR, WGS, carbonation reactions and converting it to the vapour phase, allowing the steam to pass through the turbine to generate electricity. To examine the effects of the synchronized critical parameters, response surface methodology (RSM) was used, thus allowing the optimal operational conditions to be determined in the form of an optimized zone for operation. The result of parameter optimization gave the maximum green hydrogen production of 211.46 kmol/hr, and electric power production of 2,311.68 kWh, representing increases of 34.86% and 5.62%, respectively when using 100 kmol/hr of biogas. In addition, control structures were also built to control the reactors’ temperature in the dynamic section. The tuning parameters can control the SR and WGS system’s reactor to maintain the system in approximately 0.29 h and 0.32 h, respectively.

Economic evaluation for four different solid sorbent processes with heat integration for energy-efficient CO2 capture based on PEI-silica sorbent

An amine-functionalized solid sorbent-based process with heat integration is considered an energy-efficient method for large-scale CO2 capture. Herein, we propose a techno-economic analysis (TEA) of four different solid sorbent processes for post-combustion CO2 capture with internal heat integration as an alternative to the conventional amine scrubbing process. Our proposed processes are fluidized bed adsorption, fixed bed adsorption, moving bed adsorption, and rapid thermal swing adsorption and involve continuous adsorption, heating, desorption, and cooling. In addition, the four processes use an amine-functionalized solid sorbent, SiO2/0.37 EB-PEI, which was transformed into powder, pellet, and hollow fiber to reflect the characteristics of each process. The proposed processes enable internal heat integration by recovering sensible heat from the cooling process and further enhance the CO2 cyclic capacity of amine-functionalized solid sorbents with high CO2 recovery by performing adsorption heat removal. Most importantly, our TEA based on rigorous mathematical modeling revealed that the CO2 capture cost of the four solid sorbent-based processes was approximately 48.1–75.2 $/t-CO2, with a 45%–58% sensible heat recovery. Such a low CO2 capture cost is comparable to that of the most mature amine-based absorption process (62.8 $/t-CO2), owing to a combination of internal heat integration and enhanced CO2 cyclic capacity. The results support the feasibility of four solid sorbent-based processes for post-combustion CO2 capture.

A technical and economic evaluation of two different oxygen sources for a small oxy-combustion unit

Oxy-combustion is a feasible CO2 capture method in the power and heat generation sector. This paper aims to propose a methodology for assessing two oxygen production technologies for small-scale oxy-combustion units: i) two-bed pressure swing adsorption (PSA), and ii) liquid oxygen delivery (LOX) for any local conditions, including the greenhouse gas (GHC) footprint for the oxygen that is produced. An analysis of PSA technology and LOX technology was carried out for the Czech Republic and for Germany, where the electricity, labor costs, and greenhouse gas (GHC) emission factors of electrical power differ considerably, but the equipment costs are similar.The analysis always has to be based on local prices, especially on the electricity price that is available for consumers operating PSA units and the price for liquid oxygen delivery, and also GHC emission factors for the electric energy produced in a given area or country. Depending on the local conditions, we may reach completely different conclusions concerning the technology that will be chosen for oxygen supply.

Simple and Shortcut Method for Evaluating and Guiding the Removal of Degradation Products, Improving Solvent Performance, and Reducing Regeneration Energy

Aqueous amine-based CO2 capture is considered as the most mature and applicable CO2 capture method for post-combustion. With the CO2 capture process running for a long time, the degradation of aqu...

Potential of using biomass based activated carbon for carbon dioxide capture

There are three major methods used to capture carbon dioxide (CO2) which include post-combustion, pre-combustion and oxy-fuel combustion method. Post combustion method is a technically and economically possible for CO2 capture. Generally, CO2 is first separated from a gas stream which contains CO2 and then captured. There are three main methods used to separate CO2 viz., solvent separation, membrane separation and cryogenic separation. In post combustion, for capturing CO2 different techniques such as absorption, adsorption, membrane and cryogenic distillation are used. Adsorption is the most commonly used method for CO2 capture. Activated carbon obtained from charcoal is considered as a potential adsorbent material for CO2 capture. In this study, potential of using activated carbon obtained from two biomass substances viz., coconut shell and palm shell were examined as the adsorbent materials which would be used to capture CO2. For this purpose, the surface area, porosity, surface morphology and functional groups of the samples of activated carbon chosen for the study were obtained by using Brunauer-Emmet-Teller (BET), Scanning electron microscope (SEM), Thermogravimetry (TGA) and Derivative thermogravimetry (DTG) respectively. The preparation of biomass based activated carbon, adsorption properties and characterization of adsorbents were studied and the results are presented in this paper.

Assessment of CO2 capture technologies for CO2 utilization in enhanced oil recovery

AbstractCO2 capture is considered to be a viable means of reducing the harmful environmental impacts of the fossil fuel usage. The net cost of CO2 capture can be reduced and, consequently, the adoption of CO2 capture methods can be enhanced by developing revenue streams for the captured CO2. Enhanced oil recovery (EOR), which is the process of withdrawing crude from oil reservoirs after primary and secondary withdrawal, is viewed as an attractive means of CO2 utilization. The EOR process has the capacity to take large volumes of CO2 captured from power plants and use them for the production of incremental oil. The process which is known as CO2‐EOR has synergistic benefits for the oil and gas and power generation industries. Different CO2 capture technologies are currently being used and their suitability of supplying captured CO2 for utilization in EOR may not be similar. This study analyzes the ease of utilization of CO2 captured from power plants in EOR applications. The analysis is done by comparing different capture technologies in terms of cost and purity of CO2 captured and their suitability of integration with the EOR. The results determine that the post‐combustion CO2 capture is the most EOR friendly technique in terms of CO2 stream purity, while the chemical looping combustion (CLC) is the most EOR amenable in terms of the capture cost. The results show that the CO2 capture efforts from power plants using CLC can be fully covered by additional oil revenue at oil prices above $27.9 per barrel ($175.5/m3). © 2021 The Authors. Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons, Ltd.

Simulation of a moving bed chemical looping system for electricity production from coal via chemical looping water splitting

AbstractCoal is a crucial energy source for modern industry and society. Because coal is one of the most CO2‐intensive carbonaceous fuels, the combustion of coal with CO2 capture is of great environmental relevance. However, the conventional coal‐based power generation processes, including the pulverized coal (PC) boiler process and the integrated gasification combined cycle (IGCC) process, suffer a significant efficiency loss when integrated with conventional CO2 capture methods. Chemical looping technology is a promising alternative pathway for coal‐based power generation with intrinsic CO2 separation and capture. Process simulation of chemical looping processes can provide an overview on the viability of the processes, thereby quantifying their advantages over conventional processes. This study presents the process simulation of a chemical looping water splitting combined cycle (CLWS‐CC) system for electricity generation. The CLWS‐CC process directly uses coal as the feedstock to produce H2, which is subsequently combusted in a combined cycle to generate electricity. The oxygen carriers used in the chemical looping process are optimized in their composition. Autothermal operation is established within the chemical looping system. Four CLWS‐CC cases that operate at different pressures are considered. In two of the four cases, an unequal pressure operating strategy is adopted to minimize the compression power consumption in order to enhance the overall process energy efficiency. The process simulation shows that the CLWS‐CC process is able to achieve an 18% increase in net plant efficiency over the conventional IGCC process.

Thermally stable amine-functionalized silica sorbents using one-pot synthesis method for CO2 capture at low temperature

Amine-functionalized silica sorbents have been widely investigated for post-combustion CO2 capture at low temperature. In previous studies, amine-functionalized silica sorbents were prepared using a synthetic hierarchically porous silica, which is not commercially available in large quantities, because porous silica support structures strongly influence CO2 capture performance. Here, we propose a feasible and facile fabrication method for amine-functionalized silica sorbents using 3-aminopropyltrimethoxy silane (APTS) and fumed silica (FS), where APTS serves as both an active material and a binder. The APTS-functionalized FS sorbents have large amounts of active amino groups and porous structures and demonstrate good multicycle stability with excellent CO2 capture performance. In addition, cetyltrimethylammonium bromide was found to improve the diffusion pathway of CO2, leading to enhanced CO2 capture capacity because of the suppression of excessive condensation during preparation. Therefore, the APTS-functionalized FS sorbents could be cost- and energy-efficiently prepared using a novel one-pot synthesis method; the resulting sorbents exhibit excellent CO2 capture performance.

Investigating algae for CO2 capture and accumulation and simultaneous production of biomass for biodiesel production

Carbon capture and sequestration technologies are used to reduce carbon emissions. Membranes, solvents, and adsorbents are the three major methods of CO2 capture. One of the promising methods is the use of algae to absorb CO2 from flue gases and convert it into biomass. Algae have great potential as renewable fuel sources and CO2 capture using photosynthesis for carbon fixation has also attracted much attention. This paper presents an extensive and in-depth report on the utilization of algae for carbon capture and accumulation. This is done in conjunction with cultivating the algae for the production of biomass for biodiesel production. Different systems are investigated for algae cultivation as well as carbon capture to effectively mitigate carbon emissions. The performance and productivity of these biosystems depend on various conditions including algae type, light sources, nutrients, pH, temperature, and mass transfer. Macroalgae and microalgae species were explored to determine their suitability for carbon capture and sequestration, along with the production of biodiesel. The steps for producing biodiesel were comprehensively reviewed, which are harvesting, dehydrating, oil extraction, oil refining, and transesterification. This technology combines active carbon capture with the potential of biodiesel production.

Microbial-derived functional carbon decorated hollow NiCo-LDHs nanoflowers as a highly efficient catalyst for Li-CO2 battery

As a promising method for CO2 capture and utilization, Li-CO2 battery is attracting significant attention due to its uniqueness in low-carbon technology and high output energy density. However, the practical application is plagued by the sluggish electrochemical reaction kinetic and difficult decomposition of Li2CO3. Herein, we propose a strategy to realize high capacity, large rate capability and good stability Li-CO2 battery by inducing the growth of Li2CO3 along the base face of hollow NiCo-LDHs nanoflowers. The unique morphology of the NiCo-LDHs nanoflowers make sure numerous exposed active sites and enough space for the reversible electrochemical reaction in Li-CO2 battery. Meanwhile, microbial-derived functional carbon (M-FC) is prepared to decorate the petals of the NiCo-LDHs nanoflowers, which can provide both superior electrical conductivity and co-catalyst effects to accelerate the kinetics of the electrochemical reaction. Due to the deliberate design and the synergy effect of the M-FC and NiCo-LDHs nanoflowers, the Li-CO2 battery using M-FC/NiCo-LDHs cathode exhibits a high discharge capacity (13756.8 mA h g−1), enhanced rate capability (up to 2000 mA g−1) and excellent cyclability (for 60 cycles) under optimized condition. This work opens a promising avenue for the design of high performance catalyst and the recycling utilization of hazardous microbial wastes.

Electrochemical Approaches toward CO2 Capture and Concentration

Carbon capture and concentration of low partial pressure CO2 in air and flue gas is a key step in carbon abatement strategies. Traditional CO2 capture methods employ temperature or pressure swings;...

Advances of Carbon Capture and Storage in Coal-Based Power Generating Units in an Indian Context

India is a nation with a diverse economy that requires tremendous resources to completely meet the desires of its compatriots in various sectors. In terms of energy resources and requirements, coal-based power plants can fulfill the bulk of these electricity needs. India is very reliant on coal, which is used in power plants as a primary energy source. However, the usage of coal energy at a higher level continuously pollutes the atmosphere. The Indian power market alone accounts for half of the country’s CO2 emissions, which implies that significant action is needed to contain environmental pollution. Carbon Capture and Storage (CCS) is a bridging technique and feasible alternative for the carbon fired plant processing of CO2. However, the application of CCS in coal-fired power stations is still uncommon in the nation. At the UNFCCC Paris Summit, India committed to reduce its carbon emission intensity by approximately 30–33% by 2030. In this work, several CCS systems, possible CO2 origins, and emission levels in India are discussed. Various advanced methods for CO2 capture and separation are also highlighted. Furthermore, the current work discusses CCS situations and the applications of CCS in India along with its manifold challenges.

Direct CO2 Capture from Air via Crystallization with a Trichelating Iminoguanidine Ligand.

Effectively reducing the concentration of CO2 in ambient air is essential to mitigate global warming. Existing carbon capture and storage technology can only slow down the carbon emissions of large point sources but cannot treat the already accumulated CO2 in the environment. Herein, we demonstrated a simple direct CO2 capture method from air via reactive crystallization with a new trichelating iminoguanidine ligand (BTIG). It could strongly bind CO2 to form insoluble carbonate crystals that could be easily isolated. In the crystal, CO2 was transformed to CO32– and trapped in a dense hydrogen bonding network in terms of carbonate–water clusters. This capture process was reversible, and the BTIG ligand could be regenerated by heating the BTIG–CO2 crystal at a mild temperature, which was much lower than the decomposition temperature of CaCO3 (∼900 °C). Thermodynamic and kinetics analyses indicate that the crystallization process was exothermic with an enthalpy of −292 kJ/mol, and the decomposition energy consumption was 169 kJ per mol CO2. In addition, BTIG could also be employed for CO2 capture from flue gas with a capacity of 1.46 mol/mol, which was superior to that of most of the reported sorbents.