Post-combustion CO2 Capture Technology Research Articles

Study of the Post-combustion CO2 Capture Applied to Conventional and Partial Oxy-fuel Cement Plants

The present work was focused on the application in the cement industry of the post-combustion CO2 capture technology using amine-based chemical absorption. Besides conventional conditions, investigations were performed on a concept called “partial oxy-fuel combustion” applied to cement kilns leading to more CO2-concentrated flue gas (yCO2 up to 60%) and allowing to reduce the solvent regeneration energy consumption. The purpose of the study was to highlight and evaluate this reduction. Firstly, the performances of several solvents were evaluated thanks to screening tests at lab (results with a cables-bundle contactor) and micro-pilot (absorption-regeneration unit) scales considering different CO2 contents (yCO2,in = 20-60 vol.%). Simple and blended solvents were tested in such conditions, such as primary and secondary alkanolamines (benchmark Monoethanolamine (MEA), Diethanolamine (DEA) and cyclical di-amine (Piperazine (PZ)). It was shown that the use of activated solutions (such as DEA 30 wt.% + PZ 5 wt.%) presented particularly high absorption performances both in conventional and high CO2 contents conditions. Secondly, Aspen HysysTM simulations were carried out considering cement plant flue gas. For MEA 30 wt.% an increase of yCO2 from 20% to 44% leads to a 26% decrease of the regeneration energy (from 3.36 to 2.48 GJ/tCO2), which is clearly encouraging. As perspectives, new absorption-regeneration tests at micro-pilot scale and simulations will be performed with other solvents in order to have a more global evaluation of the interest of partial oxy-fuel conditions for the cement industry.

A Review of Post-combustion CO2 Capture Technologies from Coal-fired Power Plants

Reducing CO2 emissions has become a worldwide research topic. Of all the sources of CO2 emissions, power plants burning fossil fuels, especially coals, account for a very large portion. For CO2 capture from existing coal-fired power plants, post-combustion technology is thus far considered the most viable method due to its “end-of-pipe” characteristic. Chemical absorption or scrubbing process is currently the technology most likely to be implemented in the near future but rather energy-intensive. Membrane-based CO2 separation process in recent years appears to be a competitive substitution for conventional chemical absorption technology. This paper reviews the basic process designs of chemical absorption and membrane-based separation processes for CO2 capture, as well as corresponding optimization methods including optimizing operational parameters, process modifications, membrane module types and so forth. In addition, some energetic and economic estimates from other researchers for these two CO2 capture technologies are summarized. It is found that membrane-based separation process does not possess obvious advantage over MEA-based chemical absorption process at the typical 90% CO2 capture degree in terms of both energy consumption and cost. Therefore, various optimization methods have not changed the fact that CCS technology will lay more burdens on power plants unless they can get enough allowances from government. In recent years, hybrid system with the target of utilizing more than one single capture technology seems to be new direction from the perspective of capture process design. However, it still needs to be further investigated.

MgO-based adsorbents for CO2 adsorption: Influence of structural and textural properties on the CO2 adsorption performance

A series of MgO-based adsorbents were prepared through solution–combustion synthesis and ball-milling process. The prepared MgO-based powders were characterized using X-ray diffraction, scanning electron microscopy, N2 physisorption measurements, and employed as potential adsorbents for CO2 adsorption. The influence of structural and textural properties of these adsorbents over the CO2 adsorption behaviour was also investigated. The results showed that MgO-based products prepared by solution–combustion and ball-milling processes, were highly porous, fluffy, nanocrystalline structures in nature, which are unique physico-chemical properties that significantly contribute to enhance their CO2 adsorption. It was found that the MgO synthesized by solution combustion process, using a molar ratio of urea to magnesium nitrate (2:1), and treated by ball-milling during 2.5hr (MgO-BM2.5h), exhibited the maximum CO2adsorption capacity of 1.611mmol/g at 25°C and 1atm, mainly via chemisorption. The CO2 adsorption behaviour on the MgO-based adsorbents was correlated to their improved specific surface area, total pore volume, pore size distribution and crystallinity. The reusability of synthesized MgO-BM2.5h was confirmed by five consecutive CO2 adsorption–desorption times, without any significant loss of performance, that supports the potential of MgO-based adsorbent. The results confirmed that the special features of MgO prepared by solution–combustion and treated by ball-milling during 2.5hr are favorable to be used as effective MgO-based adsorbent in post-combustion CO2 capture technologies.

Dynamic modelling of a commercial-scale CO2 capture plant integrated with a natural gas combined cycle (NGCC) power plant

MEA-based post-combustion CO2 capture technology has been considered as one of the mature technologies to mitigate CO2 emissions since it can be easily integrated to existing fossil-fired power plants. In this work, a model describing the dynamic operation of a 453MWe natural gas combined cycle (NGCC) power plant integrated with a commercial-scale post-combustion CO2 capture plant has been developed. The proposed model has been used to evaluate the dynamic performance of the integrated process under various scenarios, e.g. changes in the reboiler heat duty and power plant inputs. In addition, the transient operation of the integrated plant using a pre-defined (scheduled) trajectory profile in the consumption of steam in the reboiler unit has been compared to the case of constant withdrawal of steam from the power plant. The results show that a coordinated effort between the two plants is needed to run the integrated plant efficiently and at near optimal economic points under changes in power demands. The insights gained through this analysis will be instrumental to design basic and advanced control and scheduling strategies for the integrated NGCC-CO2 capture plant.

Enhancing the energetic efficiency of MDEA/PZ-based CO2 capture technology for a 650 MW power plant: Process improvement

Post-combustion CO2 capture (PCC) facilities are set up at the power plants to reduce their carbon footprint. However, the high energy demand of the amine-based PCC technologies significantly decreases the net energy efficiency of a power plant. This work focused on developing an optimal amine-based PCC technology by carefully analyzing and integrating the energy flow. The methyldiethanolamine (MDEA) solution of lower reaction heat with CO2 is found to be a superior solvent than monoethanolamine (MEA). Process analysis using the equilibrium stage model in Aspen Plus was performed to investigate the effects of piperazine (PZ) promoter and various operation parameters such as absorption pressure, stripping pressure, CO2 loading in lean solution, and CO2 removal ratio on the net efficiency penalty of MDEA/PZ-based PCC process. Several enhancement measures, including the absorber intercooling, simple rich-split, advanced rich-split, and stripper interheating, were found significantly improving the process energetic efficiency. A reboiler heat duty (Qreb) as low as 2.24GJ/tCO2 was achieved which is 27.7% lower than that of its counterpart (MEA). The enhanced MDEA/PZ-based technology leads to a low net power efficiency penalty of 7.66% which is 16.1% less than that of the benchmark MEA-based technology. This improvement corresponds to an absolute increase of 1.47% in net efficiency of a 650MW power plant with PCC units.

Energy and Exergy Analyses of a Power Plant With Carbon Dioxide Capture Using Multistage Chemical Looping Combustion

A thermodynamic model and parametric analysis of a natural gas-fired power plant with carbon dioxide (CO2) capture using multistage chemical looping combustion (CLC) are presented. CLC is an innovative concept and an attractive option to capture CO2 with a significantly lower energy penalty than other carbon-capture technologies. The principal idea behind CLC is to split the combustion process into two separate steps (redox reactions) carried out in two separate reactors: an oxidation reaction and a reduction reaction, by introducing a suitable metal oxide which acts as an oxygen carrier (OC) that circulates between the two reactors. In this study, an Aspen Plus model was developed by employing the conservation of mass and energy for all components of the CLC system. In the analysis, equilibrium-based thermodynamic reactions with no OC deactivation were considered. The model was employed to investigate the effect of various key operating parameters such as air, fuel, and OC mass flow rates, operating pressure, and waste heat recovery on the performance of a natural gas-fired power plant with multistage CLC. The results of these parameters on the plant's thermal and exergetic efficiencies are presented. Based on the lower heating value, the analysis shows a thermal efficiency gain of more than 6 percentage points for CLC-integrated natural gas power plants compared to similar power plants with pre- or post-combustion CO2 capture technologies.

Design and operation of a 300 kWth indirectly heated carbonate looping pilot plant

Carbonate looping or calcium looping (CaL) is an efficient post-combustion CO2-capture technology particularly suited for retrofitting existing power plants. Limestone, an inexpensive and highly available natural product, is utilized for the CaL process. A new concept with an indirectly heated calciner is presented, where the heat for calcination is transferred by means of heat pipes from an external combustor. This process modification offers higher plant efficiencies and lower CO2 avoidance costs than an oxy-fired CaL process. The worldwide first indirectly heated CaL pilot plant with a nominal power of 300kWth has been erected at Technische Universität Darmstadt. This paper presents the layout of the pilot plant and first operational results using a natural limestone as sorbent and propane as fuel for the external combustor. The calciner was fluidized with air to support self-fluidization of the sorbent during calcination and to lower the partial CO2 pressure and therewith the calcination temperature. Proof of concept was demonstrated within more than 400h continuous testing. The reactor system showed good hydrodynamic stability, and the heat pipe heat exchanger an excellent performance. CO2 capture rates up to 90% in the carbonator were reached.

Low-Temperature Carbon Capture Using Aqueous Ammonia and Organic Solvents

Current postcombustion CO2 capture technologies are energy intensive, require high-temperature heat sources, and dramatically increase the cost of power generation. In this work, we introduce a new carbon capture process requiring significantly lower temperatures and less energy, creating further impetus to reduce CO2 emissions from power generation. In this process, high-purity CO2 is generated through the addition of an organic solvent (acetone, dimethoxymethane, or acetaldehyde) to a CO2 rich, aqueous ammonia/carbon dioxide solution under room-temperature and -pressure conditions. The organic solvent and CO2-absorbing solution are then regenerated using low-temperature heat. When acetone, dimethoxymethane, or acetaldehyde was added at a concentration of 16.7% (v/v) to 2 M aqueous ammonium bicarbonate, 39.8, 48.6, or 86.5%, respectively, of the aqueous CO2 species transformed into high-purity CO2 gas over 3 h. Thermal energy and temperature requirements for recovering acetaldehyde, the best-performing o...

A Remotely-Operated Facility for Evaluation of Post-Combustion CO2 Capture Technologies on Industrial Sites

Abstract—ACTTROM (Advanced Capture Testing in a Transportable Remotely-Operated Minilab) is a transportable test facility for bench-scale evaluation of post-combustion CO2 capture technologies using real industrial flue gases. It is designed to be remote-operable, requiring visits only once per month for maintenance and sample collection. ACTTROM is the first facility of its kind, owned and operated by academia for collaborative research in an industrial environment, and this has resulted in a number of unique developments to facilitate remote operation at an industrial host site. Specifically, it has been necessary to design the unit to automatically correct or mitigate the effects of fault conditions, and to be remotely-monitored via a user interface at 24 hour intervals.

Attrition resistance of calcium oxide–copper oxide–cement sorbents for post-combustion carbon dioxide capture

Integrating calcium looping (CaL) and chemical looping combustion (CLC) is potentially more energy efficient than existing technology for post-combustion CO2 capture. Mixtures of CaO, CuO and cement (cem) are promising sorbents but attrition losses due to abrasion and fragmentation could incur an unacceptable economic penalty. We assessed the attrition resistance of many fluidized bed powders with a jet mill at orifice velocities from 180ms-1 to sonic velocity. The attrition resistance of calcium oxide–copper oxide–cement sorbents and crushed cadomin limestone are poorer than vanadyl pyrophosphate (VPP) and fluid catalytic cracking catalyst (FCC). The attrition rates of VPP and FCC at an orifice gas velocity of 180ms−1 were 5mgh−1 and 7mgh−1, respectively; it was 10mgh−1 for powders with a mass fraction of 50% CuO 40% CaO and 10% cement. The (CaO)90cem fragments to smaller sister particles and produces fines but the fines collected overhead in the thimble filter decreases with temperature. The (CaO)40(CuO)50cem10 attrition resistance improved above 500°C and the d50 of the pellets remaining in the jet cup increased from 330μm to 422μm: the Cu agglomerated the pellets. Attrition rates increased with the square of the orifice diameter, the cube of the gas velocity and to the power 0.4 with gas molecular weight.

A new integration model of the calcium looping technology into coal fired power plants for CO2 capture

The Ca-Looping (CaL) process is at the root of a promising 2nd generation technology for post-combustion CO2 capture at coal fired power plants. The process is based on the reversible and quick carbonation/calcination reaction of CaO/CaCO​3 at high temperatures and allows using low cost, widely available and non toxic CaO precursors such as natural limestone. In this work, the efficiency penalty caused by the integration of the Ca-looping technology into a coal fired power plant is analyzed. The results of the simulations based on the proposed integration model show that efficiency penalty varies between 4% and 7% points, which yields lower energy costs than other more mature post-combustion CO2 capture technologies such as the currently commercial amine scrubbing technology. A principal feature of the CaL process at CO2 capture conditions is that it produces a large amount of energy and therefore an optimized integration of the systems energy flows is essential for the feasibility of the integration at the commercial level. As a main novel contribution, CO2 capture efficiency is calculated in our work by considering the important role of the solid-state diffusion controlled carbonation phase, which becomes relevant when CaO regeneration is carried out under high CO2 partial pressure as is the case with the CaL process for CO2 capture. The results obtained based on the new model suggest that integration energy efficiency would be significantly improved as the solids residence time in the carbonator reactor is increased.

Human health risks of post- and oxy-fuel combustion carbon dioxide capture technologies: Hypothetically modeled scenarios

Carbon dioxide (CO2) capture technology has become an available technology for ensuring reduction of greenhouse gas emissions from fossil-fuel based electricity generating plants. Since public acceptance of this technology depends critically on a reliable demonstration of its safety, it is important that the risks associated with carbon capture technology be fully understood so that standards and regulatory frameworks required for its deployment can be formulated.The objective of this paper is to evaluate the predicted risk to human health associated with the Boundary Dam Power Station (BDPS) close to Estevan, Saskatchewan, Canada. This study aims to predict the potential instead of actual risks to human health because real data from the power plants’ stacks are unavailable. Instead, the study relies on data that were entirely derived from the Life Cycle Assessment (LCA) studies (Koiwanit et al., 2014a,b; Manuilova, 2011). The risk assessment was conducted based on two tools: (i) the American Meteorological Society's Environmental Protection Agency Regulatory Model (AERMOD), and (ii) Health Canada's Air Quality Benefits Assessment Tool (AQBAT). The conventional lignite-fired electricity generation station at the BDPS is used as a reference case. This work presents the predicted risks to human health due to exposure to air pollution which has been released by the post-combustion carbon dioxide capture process, and compare the risks with those posed by the oxy-fuel CO2 capture technology.Nitrogen dioxide (NO2), particulates less than 2.5μm in diameter (PM2.5), and sulfur dioxide (SO2) emissions were modeled in a circular pattern of 10 degree increments with 25 zones of 100m on each increment. This study demonstrates that the reductions in the atmospheric concentrations of NO2, PM2.5, and SO2 accounted for the largest improvements in human health impacts, particularly in terms of acute respiratory, asthma symptoms, and restricted activity health outcomes. In addition, the oxy-fuel CO2 capture system reduced emissions to the atmosphere more effectively than the post-combustion CO2 capture technology. Therefore, the former technology's contribution to reducing air pollution is more significant than that of the latter.

Evaluating the Activity and Stability of CaO-based Sorbents for Post-combustion CO2 Capture in Fixed-bed Reactor Experiments

Carbonate Looping is a post-combustion CO2 capture technology in which CO2 is captured by a CaO-based sorbent. In this work, we report the development, preliminary evaluation and bench-scale testing of synthetic and natural sorbents. After preliminary screening, the most promising materials were studied in a fixed bed reactor under realistic flue gas feed composition. Zr and Al-doped synthetic CaO based sorbents exhibited very high sorption capacity and stability, due to their porous structure that is retained after 20 consecutive carbonation/calcination cycles. The natural sorbents presented inferior results, however their regeneration via hydration seems possible. The presence of steam in the flue gases seems to enhance sorption capacity and stability.

Introduction and evaluation of a double loop staged fluidized bed system for post-combustion CO2 capture using solid sorbents in a continuous temperature swing adsorption process

A double loop staged fluidized bed system operated with solid amine sorbents is proposed and evaluated for temperature swing adsorption (TSA) CO2 separation from flue gas streams. The proposed system features effective counter-current movement of gas and sorbent streams in both gas–solid contactors, i.e. the adsorber and the desorber. The counter-current movement enables the realization of axial CO2 concentration profiles within both contactors that is exploited within the TSA process to reach high CO2 capture rates as well as concentrated CO2 from the desorber. The system comprises two multi-stage fluidized bed contactors where the sorbents move downwards through a series of bubbling fluidized bed stages. The stages are made up by nozzle or sieve plates and feature downcomers or dip tubes to allow for downward directed particle flow. The gas is fed at the bottom and serves as fluidizing agent in the stages. The particles are removed from the bottom stage through chutes and are directed through a sealing device (loop seal or purged moving bed) towards a transporting riser. The particles are lifted up, separated from the transport gas via gravitational or centrifugal separators and sent to the respective other contacting device through simple chutes. Lean/rich heat transfer may be possible using fluidized bed heat exchangers within the dense bed phase of both transport risers. The process is thermodynamically evaluated for a well-studied sorbent material consisting of a porous silica support that is functionalized with a mixture of two different amines (PEI+APTES). It is shown that application of the double loop staged system leads to a significant reduction of sorbent circulation rate and stripping steam demand compared to single-stage fluidized bed systems and thus to a significant reduction of the energy demand of the CO2 capture process. It is found that when implementing five stages in each contacting device, it is possible to capture 90% of the CO2 from a typical flue gas stream (10vol% CO2 content), even when the process is operated with moderate sorbent circulation and stripping steam rates. The corresponding overall heat requirement of the capture process without accounting for CO2 compression and effective heat integration is 3.5MJ per kg CO2 captured and, thus, equal or even below the values reported for liquid amine capture systems. Improved heat transfer through immersed fluidized bed heat exchangers as well as a significantly lower number of theoretical stages indicate that the proposed TSA contacting devices will allow for a more compact design as compared to gas–liquid systems, which would lead to reduced capital costs. In conclusion, CO2 capture within the proposed TSA system using solid amine sorbents may be regarded as a promising post-combustion CO2 capture technology.

Facile Carbon Fixation to Performic Acids by Water-Sealed Dielectric Barrier Discharge.

Carbon fixation refers to the conversion of carbon dioxide (CO2) to organic materials, as commonly performed in nature through photosynthesis by plants and other autotrophic organisms. The creation of artificial carbon fixation processes is one of the greatest challenges for chemistry to solve the critical environmental issue concerning the reduction of CO2 emissions. We have developed an electricity-driven facile CO2 fixation process that yields performic acid, HCO2OH, from CO2 and water at neutral pH by dielectric barrier discharge with an input electric power conversion efficiency of currently 0.2−0.4%. This method offers a promising future technology for artificial carbon fixation on its own, and may also be scaled up in combination with e.g., the post-combustion CO2 capture and storage technology.

Carbon Capture and Storage for Enhanced Oil Recovery: Integration and Optimization of a Post-Combustion CO2-Capture Facility at a Power Plant in Abu Dhabi

Summary Masdar has initiated the Abu Dhabi Carbon-Capture and -Storage Project, with the objective to develop a carbon-capture network in Abu Dhabi capable of creating large reductions of carbon dioxide (CO2) emissions and with the capacity to increase oil recovery by use of CO2 for enhanced oil recovery (EOR). Because Siemens (henceforth referred to as the Technology Owner) has developed, tested, and piloted a proprietary post-combustion CO2-capture technology (PostCapTM) for the removal of CO2 from the flue gas of coal- and gas-fired power plants suitable for the project, both parties decided to cooperate in executing a front-end engineering and design (FEED) study. The technology is based on an aqueous amino-acid-salt solution. The Technology Owner and Masdar have completed a FEED study for capturing 1,800,000 tons of CO2 annually from a natural-gas-fired power plant in Abu Dhabi by application of the PostCapTM technology. Various opportunities and challenges were encountered during the design of the retrofit capture plant. Challenges were often specific to the region, including local climate, water availability, and flue-gas quality. Design and optimization of the plant were influenced by local energy and labor prices. Further opportunities included integration with the power plant and with a local industrial facility. The power plant had to supply the capture plant with steam and power without reducing the original electricity-production capacity. To accomplish this, several heat- and power-integration concepts were evaluated with respect to their feasibility, including the application of a backpressure steam turbine and the retrofit of a simple-cycle gas turbine to combined-cycle gas turbine. Various cooling options were considered in view of climate and resource challenges. Cooling water had to be extracted from a reflux stream produced by an adjacent industrial facility. Drawing on the results of the FEED study, this paper presents the manner in which PostCapTM technology can be applied for capturing CO2 at a power plant in Abu Dhabi for the purpose of EOR, while satisfying specific local needs, and the way utility supply and power plant integration can be facilitated.

Benchmarking of a novel solid sorbent CO2 capture process for NGCC power generation

The successful deployment of any technology depends on many important factors. One of the critical ones that affect the success of post combustion CO2 capture technologies is the ability to reduce the increase in cost of electricity associated with retrofitting the capture unit to electricity generating power plants. High capture costs associated with conventional MEA solvent processes has opened an opportunity for the emergence of many competing technologies aimed at reducing the cost of capture. This paper presents the technical and economic benchmarking of a polyethyleneimine (PEI)-based solid sorbent CO2 capture process as compared to the conventional MEA solvent process, with both technologies applied to a natural gas combined cycle (NGCC) power plant.The results of this evaluation indicate that the PEI-based sorbent process requires approximately 25% less regeneration steam than the conventional MEA process primarily due to avoiding the energy demand required for heat of vaporization of water in the MEA process. The PEI solid sorbent based process results in approximately 6.3 power plant efficiency point reduction as opposed to an 8 efficiency points for the MEA based process. The design of the fluidized-bed absorption and regeneration reactors in the novel solid sorbent process result in significant reductions in capital costs (21% reduction compared to MEA). The economic evaluation shows that the PEI-based solid sorbent process offers attractive reductions in the cost of electricity and the CO2 capture cost. The estimated cost of electricity, after adding the CO2 capture process, is found to be 85 and 81.7$/kWh for the MEA-based and PEI based process, respectively. Moreover, the cost of CO2 avoided for both process is estimated to be 69.8 and 62$/ton CO2 for the MEA and PEI process, respectively.

Influence of Dissolved Metals on N-Nitrosamine Formation under Amine-based CO2 Capture Conditions.

As the prime contender for postcombustion CO2 capture technology, amine-based scrubbing has to address the concerns over the formation of potentially carcinogenic N-nitrosamine byproducts from reactions between flue gas NOx and amine solvents. This bench-scale study evaluated the influence of dissolved metals on the potential to form total N-nitrosamines in the solvent within the absorber unit and upon a pressure-cooker treatment that mimics desorber conditions. Among six transition metals tested for the benchmark solvent monoethanolamine (MEA), dissolved Cu promoted total N-nitrosamine formation in the absorber unit at concentrations permitted in drinking water, but not the desorber unit. The Cu effect increased with oxygen concentration. Variation of the amine structural characteristics (amine order, steric hindrance, -OH group substitution and alkyl chain length) indicated that Cu promotes N-nitrosamine formation from primary amines with hydroxyl or carboxyl groups (amino acids), but not from secondary amines, tertiary amines, sterically hindered primary amines, or amines without oxygenated groups. Ethylenediaminetetraacetate (EDTA) suppressed the Cu effect. The results suggested that the catalytic effect of Cu may be associated with the oxidative degradation of primary amines in the absorber unit, a process known to produce a wide spectrum of secondary amine products that are more readily nitrosatable than the pristine primary amines, and that can form stable N-nitrosamines. This study highlighted an intriguing linkage between amine degradation (operational cost) and N-nitrosamine formation (health hazards), all of which are challenges for commercial-scale CO2 capture technology.

Experimental Studies of Reboiler Heat Duty for CO2 Desorption from Triethylenetetramine (TETA) and Triethylenetetramine (TETA) + N-Methyldiethanolamine (MDEA)

Amine scrubbing is regarded as one of the most suitable technologies for postcombustion CO2 capture. However, data on regeneration energy and performance is limited in literature. In this study, the reboiler heat duties of triethylenetetramine (TETA) and triethylenetetramine (TETA) + N-methyldiethanolamine (MDEA) were experimentally evaluated in a bench-scale stripper packed with Dixon ring random packing. The effects of various operating parameters on the desorption performance (presented in terms of reboiler heat duty, Qreboiler) were investigated, including lean loading, rich loading, amine concentration, solvent flow rate, and amine type. The experimental results showed that the Qreboiler was very sensitive to these process parameters. In addition, a comparison of the Qreboiler of TETA, monoethanolamine (MEA), and diethylenetriamine (DETA) was conducted to evaluate the potential for TETA’s application in the CO2 capture process. The results obtained in this work showed that the Qreboiler of TETA, as a...

Effect of SO2 on CO2 Absorption in Flue Gas by Ionic Liquid 1-Ethyl-3-methylimidazolium Acetate

Significant efforts are being made to develop several novel solvents or materials for postcombustion CO2 capture technology. Traditional amine solvents suffer from mass loses due to its volatility and poisoning by flue gas impurities. Ionic liquids (ILs) are considered to be promising alternatives for CO2 capture due to their unique features, such as negligible vapor pressure. Despite the extensive research on CO2 capture by ILs, few studies have investigated the effect of flue gas components on CO2 absorption performance. Because of the large differences between CO2 and SO2 in the absorption capacity and partial pressure in flue gas, it is essential to study the role of SO2 in CO2 capture using ILs. This work focused on studying the effect of SO2 with low concentration on postcombustion CO2 capture by 1-ethyl-3-methylimidazolium acetate [C2mim][OAc] and explaining the microscopic mechanism through quantum chemical calculation. Results showed that the CO2 absorption capacity was largely decreased by 25% i...