Industrial CO2 Capture Research Articles

Mass transfer investigation and operational sensitivity analysis of amine-based industrial CO2 capture plant

Abstract In this article, the industrial process of CO2 capture using monoethanolamine as an aqueous solvent was probed carefully from the mass transfer viewpoint. The simulation of this process was done using Rate-Base model, based on two-film theory. The results were validated against real plant data. Compared to the operational unit, the error of calculating absorption percentage and CO2 loading was estimated around 2%. The liquid temperature profiles calculated by the model agree well with the real temperature along the absorption tower, emphasizing the accuracy of this model. Operational sensitivity analysis of absorption tower was also done with the aim of determining sensitive parameters for the optimized design of absorption tower and optimized operational conditions. Hence, the sensitivity analysis was done for the flow rate of gas, the flow rate of solvent, flue gas temperature, inlet solvent temperature, CO2 concentration in the flue gas, loading of inlet solvent, and MEA concentration in the solvent. CO2 absorption percentage, the profile of loading, liquid temperature profile and finally profile of CO2 mole fraction in gas phase along the absorption tower were studied. To elaborate mass transfer phenomena, enhancement factor, interfacial area, molar flux and liquid hold up were probed. The results show that regarding the CO2 absorption, the most important parameter was the gas flow rate. Comparing liquid temperature profiles showed that the most important parameter affecting the temperature of the rich solvent was MEA concentration.

Thermodynamic characterisation of aqueous alkanolamine and amine solutions for acid gas processing by transferable molecular models

The development of new alkanolamines/amines is a topic which has attracted a great deal research interest, particularly as absorbents for the removal of acid gases from industrial sources and CO2 capture applications. One of the major challenges when evaluating the techno-economic performance of selected new single amines or blends is the lack of experimental data on the thermophysical properties required for a reliable process design and simulation. In this contribution, a robust theoretical framework for the description of key thermophysical properties of aqueous solutions of single and mixed alkanolamines/amines at relevant gas separation process conditions is proposed. The approach is based on the coupling of the Free-Volume Theory and the Density Gradient Theory with a molecular-based equation of state (soft-SAFT) for the integrated modelling of phase behaviour, enthalpies, densities, viscosities and interfacial tensions. The alkanolamines and amines investigated differ in their family and structure, and included primary (monoethanolamine), secondary (diethanolamine), tertiary (methyldiethanolamine), sterically hindered (2-amino-2-methyl-1-propanol) and cyclic amines (piperazine). The study was performed in a systematic manner, starting from the development of the models for the pure amines, the description of their thermophysical properties, and the properties of the aqueous mixtures. Compared to other models described in literature, the present modelling approach preserves the effects due the chemical structure and key intermolecular interactions of the examined alkanolamines/amines through a set of molecular parameters obtained from pure substance data, whenever available, or transferred from substances of different chemical families. This enabled the development of a consistent modelling framework which can provide reliable thermodynamic property predictions of both single and blended amine solutions over a broad range of temperatures (298–373 K) and compositions (0–50 wt% amine). The proposed approach is well-suited for implementation and extension to other alkanolamines and amines, making it a valuable tool for having reliable process simulations as well as for the screening and discovery of new amine systems, which will be required for the deployment of more economical acid gas removal processes.

Nanoparticles Embedded in Amphiphilic Membranes for Carbon Dioxide Separation and Dehumidification.

Polymers containing ethylene oxide (EO) groups have gained significant interest as the EO groups have favorable interactions with polar molecules such as H2 O, quadrupolar molecules such as CO2 , and metal ions. However, the main challenges of poly(ethylene oxide) (PEO) membranes are their weak mechanical properties and high crystallinity nature. The amphiphilic copolymer made from PEO terephthalate and poly(butylene terephthalate) (PEOT/PBT) comprises both hydrophilic and hydrophobic segments. The hydrophilic PEOT segment is thermosensitive, which facilities gas transports whereas the hydrophobic PBT segment is rigid, which provides mechanical robustness. This work demonstrates a new strategy to design amphiphilic mixed matrix membranes (MMMs) by incorporating zeolitic imidazolate framework, ZIF-71, into the PEOT/PBT copolymer. The resultant membrane shows an enhanced CO2 permeability with an ideal CO2 /N2 selectivity surpassing the original PEOT/PBT and Robeson's Upper bound line. The nanoparticles-embedded amphiphilic membranes exhibit characteristics of high transparency and mechanical robustness. Mechanically strong composite hollow fiber membranes consisting of PEOT/PBT/ZIF-71 as the selective layer were also prepared. The resultant hollow fibers possess an excellent CO2 permeance of 131 GPU (gas permeation units), CO2 /N2 selectivity of 52.6, H2 O permeance of 9300 GPU and H2 O/N2 selectivity of 3700, showing great potential for industrial CO2 capture and dehumidification.

Industrial CO2 and Carbon Capture: Near-term Benefit, Long-term Necessity

Industry emits approximately 1 billion tonnes of CO2 each year (1 GTCO2/yr) in the United States–one-third of US stationary emissions–and an even greater amount in industry-heavy China. We hypothesize that capturing industrial CO2 offers a near-term pathway to jumpstart CO2 capture and storage (CCS) and is a long-term necessity to stabilize atmospheric CO2 in order to avoid catastrophic climate impacts. We explore this proposition using several new CO2 emissions and storage databases for the United States, as well as emerging research including the economics of industrial CO2 capture. We refer to our new “sources of CO2 that are not electricity” database as SCO2NE.

CO2stCap - Cutting Cost of CO2 Capture in Process Industry

This paper is a presentation of the CO2stCap project to be undertaken in the four year project period (2015 – 2019). The project focuses on partial CO2 capture in process industry and how this can be applied to reduce cost. By performing techno–economic analyses, the optimal capture rate, including optimal design, application and configuration for different industry sources can be obtained. Cost estimation methods are used as a basis to identify and verify potentials for cost reduction when applying different options for implementation of partial CO2 capture. CO2stCap. Industries studied in this project are pulp & paper, steel, cement and metallurgical production of silicon for solar cells.

20 Years of Monitoring CO2-injection at Sleipner

The Sleipner CO2 injection project was the world's first industrial offshore CO2 Capture and Storage (CCS) project with more than 16 Mt CO2 injected since 1996. Key monitoring insights from Sleipner are the dual interpretation of seismic and gravimetric monitoring surveys to quantify the free CO2 mass changes and plume geometry development as a function of time. The learnings from Sleipner have contributed to making guidelines for monitoring future CCS injection projects, showing that selection of monitoring technology and the timing and extent of monitoring surveys should be case specific and risk based, while also taking into account the long term nature of CCS projects.

Pentaethylenehexamine loaded SBA-16 for CO2 capture from simulated flue gas

Separation of carbon dioxide (CO2) by adsorption can reduce the cost of carbon capture and storage (CCS). Amine-functionalized adsorbents are promising candidates for CO2 capture. In general, amine-functionalized adsorbents for CO2 adsorption are synthesized by an impregnation method. In this work, an amine-functionalized adsorbent was prepared by impregnating Pentaethylenehexamine (PEHA) on mesoporous silica SBA-16. The as-prepared adsorbents were characterized by X-ray Powder Diffraction (XRD), Thermal Gravimetric Analysis (TGA) and nitrogen adsorption/desorption. The results showed that the surface area, pore size and pore volume of the prepared adsorbent decreased with the increase of PEHA loading, while the basic pore structure remained unchanged. CO2 adsorption performance was studied on a Differential Scanning Calorimetry & Thermogravimetric Analysis (DSC–TGA) device and a fixed adsorption column equipped with an on-line Gas Chromatography (GC) device. When the temperature was in the range of 303K to 343K, the adsorption capacity increased with the increase of temperature, but the adsorption capacity decreased at 353K. The adsorption capacity rose from 1.6mmol/g-adsorbent to 2.1mmol/g-adsorbent when the amount of loaded PEHA reached 40wt% (343K). The adsorption capacity is improved by the presence of water vapor in the simulated flue gas. The O2 and NO have little effect on the adsorption process. When the concentration of SO2<100ppm, the adsorption process is unaffected. However, the adsorption process would be affected by the presence of high concentration SO2 (>100ppm). The dynamic adsorption performance was studied by using a fixed adsorption column. The results indicated that the adsorption process maintained a steady adsorption rate of 0.033mmol/min for each adsorption temperature before CO2 adsorption breakthrough. The adsorption capacity maintained almost the same after 20cycles of adsorption/regeneration under simulated flue gas conditions. This work presents a thermally stable adsorbent with relatively high CO2 adsorption capacity, optimum adsorption and regeneration temperatures, as well as favorable CO2 adsorption/desorption performance under simulated flue gas conditions. These properties make the adsorbent suitable for industrial CO2 capture application.

Experimental study of regeneration performance for CO2 desorption from a hybrid solvent MEA‐methanol in a stripper column packed with three different packing: Sulzer BX500, mellapale Y500 and pall rings 16 × 16

The regeneration heat duty (Qreg, MJ/kg CO2) which consists of solvent heating energy (Qsh, MJ/kg CO2), solvent vaporization energy (Qvap, MJ/kg CO2), and desorption energy (Qdes, MJ/kg CO2), is a critical parameter in evaluating the performance of a solvent for postcombustion CO2 capture. In this study, Qreg of CO2 desorption from rich monoethanolamine (MEA)‐methanol solvent was experimentally evaluated in a pilot‐plant stripper packed with Sulzer packing BX500, Mellapale packing Y500 and Pall rings 16 × 16. And a comparison of Qreg between MEA‐methanol and aqueous MEA solvent was performed to evaluate the potential for MEA‐methanol's application in industrial CO2 capture process. Also effects of several operating parameters of the stripper consists of rich CO2 loading (0.25–0.52 mol/mol), rich solvent flow rate (21.2–51.4 L/h), rich solvent temperature (40–60°C) and regeneration temperature (68–74°C) on the regeneration performance of the stripper were studied. It was found that Qreg of MEA‐methanol solvent was lower than aqueous MEA solvent (especially Qdes) and Qreg was sensitive to all the four parameters. Also the results obtained in this work showed that the stripper performance of Sulzer BX500 packing was better than Mellapale Y500 packing and Pall rings 16 × 16 packing was the worst. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 838–844, 2017

Postcombustion CO2 capture using diethylenetriamine (DETA) solvent in a pilot‐plant test bed compared to monoethanolamine (MEA) solvent

The performance of CO2 absorption into diethylenetriamine (DETA) solvent and CO2 desorption from rich DETA solvent were experimentally investigated in a lab‐scale CO2 capture test bed. And the results were compared with monoethanolamine (MEA) solvent, which is a standard solvent for CO2 capture in industry. Also, effects of solvent concentration, lean CO2 loading, lean solvent temperature, solvent flow rate and flue gas flow rate on the absorption performance of DETA and MEA solvent, and effects of lean CO2 loading and solvent flow rate on the regeneration performance of DETA and MEA solvent were studied. The results showed that DETA had a faster CO2 absorption rate and a higher CO2 cyclic capacity than MEA solvent. And to strip the same amount of CO2, DETA needed less regeneration energy than MEA solvent. In addition, the results also showed that key operating parameters of absorber and stripper had large effects on the performance of CO2 absorption and desorption. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1131–1138, 2017

Gate-opening upon CO2 adsorption on a metal-organic framework that mimics a natural stimuli-response system.

A dynamic metal-organic framework that consists of d-champhorate-based homochiral protuberant-grid-type networks can successively participate in gate-opening and closing processes for many cycles, which were triggered by the stimuli of the adsorption and desorption of CO2 to highly and specifically recognize CO2 over N2 and H2 with a high CO2 uptake of 90 mg g-1 under 35 bar at 298 K. It is highly thermally stable and the structure remains intact at least for ten reversible gate-opening and -closing processes. Thus, it is a potential candidate for industrial CO2 capture and facile release.

A new MOF-505@GO composite with high selectivity for CO2/CH4 and CO2/N2 separation

Novel MOF-505@GO composites comprised of a copper-based metal-organic framework and graphite oxide (GO) were synthesized by a solvothermal method for effective separation of CO2/CH4 and CO2/N2, which are challenging chemical separations in industry. The composites were characterized by various techniques including powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and porosity measurement through nitrogen adsorption at cryogenic temperature. Single component adsorption isotherm measurements of CO2, CH4 and N2 were performed at different temperatures. The selectivities of CO2/CH4 and CO2/N2 were estimated on the basis of ideal adsorbed solution theory (IAST). MOF-505@GO composites showed higher porosity and enhanced CO2 adsorption compared to its parent compound MOF-505. MOF-505@5GO exhibited the highest CO2 uptake of 3.94mmol/g at 298K and 100kPa, having an increase of 37.3% in comparison with the parent MOF-505. The significant improvement of CO2 uptakes could be attributed to not only new micropores and unsaturated metal sites formed in the MOF-505@GO, but also enhanced surface dispersive forces of the composites. The experimental adsorption isotherms of CO2, CH4 and N2 were well fitted with dual site Langmuir-Freundlich (DSLF) model. The CO2/CH4 and CO2/N2 adsorption selectivities were up to 8.6 and 37.2 at 298K and 100kPa, respectively, predicted by IAST. More strikingly, the composites showed excellent moisture stability, which was confirmed by PXRD analysis. These superior performances suggested that the MOF-505@GO composites are promising candidates for industrial CO2 capture.

Computational investigation of Cu7 as a model biomimetic CO2 capture catalyst

Density functional theory calculations were carried out with a stable seven atom pentagonal bipyramidal copper cluster acting as a biomimetic CO2 hydration catalyst exhibiting carbonic anhydrase-like mechanism. The cluster was found to be active for catalyzing the reaction resulting in the formation of bicarbonate ions and protons. The reaction pathway was found to be identical to that of the α-carbonic anhydrase action involving water adsorption and deprotonation, CO2 interaction and proton transfer, and water attack and HCO3− displacement steps. The calculations were carried out both in vacuum and in water as the solvent. No significant differences in the energetics of the elementary steps were observed in vacuum and in solvated state indicating the feasibility of the use of Cu7 as the active species in industrial gas-phase CO2 capture systems.

Pilot tests of CO2 capture in brick production industry using gas–liquid contact membranes

It is generally accepted that carbon capture and storage strategies will play a crucial role for mitigating CO2 emissions at short- and mid-term scenarios. In this study, a membrane gas absorption process was assessed as potential candidate method for CO2 capture in a Greek brick production industry. The membrane contactor pilot unit was installed near the flue, where a slip stream of the flue gases was continuously sampled and fed in the hollow fiber membrane module. A 0.25 M aqueous diethanolamine solution was used as a typical solvent for CO2 capture. The % CO2 removal was chosen as a typical performance indicator and the liquid to gas flow ratio was chosen as the main controlling variable of the process. The test results indicate that almost complete CO2 removal can be attained with a liquid to gas flow rate around 1, demonstrating the high potential of the proposed technology.

Synthesis of amine-modified solid Fe-Zr adsorbents for CO2adsorption

BACKGROUND With the aggravation of the greenhouse effect, much attention is given to the capture of CO2 before its emission into the atmosphere. So far, various solid adsorbents have been developed and used. Among them, solid materials modified with organic-amines are promising on account of good adsorption and desorption performance. In the present work, triethylenetetramine (TETA) modified solid Fe-Zr adsorbents were synthesized and characterized. The performance of the adsorbents for CO2 adsorption was tested in a stream of 5% CO2. RESULTS The Fe-Zr support was first synthesized, and TETA was successfully grafted onto its surface. The adsorbents show good thermal stability and CO2 adsorption ability. Increase in the amount of TETA and increased gas flow rate have a positive influence whereas increase of the adsorption temperature has a negative effect on CO2 adsorption capacity. At 200 mg TETA loading and a flow rate of 20 cm3 g−1, the adsorbent achieves a maximum adsorption capacity of 4.1 mmol g−1 at 75 °C. In addition, the adsorbent exhibits excellent reusability and cyclic performance. CONCLUSION Remarkable adsorption capacity and good recyclability suggest that synthesized TETA-functionalized Fe-Zr adsorbents have high potential for CO2 capture in industry. © 2015 Society of Chemical Industry

Pre-combustion CO2 capture

This paper, which is part of a special issue of the International Journal of Greenhouse Gas Control, gives an overview of the latest achievements in the pre-combustion decarbonisation route for the production of electricity with CO2 capture. Pre-combustion technologies applied to two different fuels are considered, natural gas and coal, since they cover most of electricity production from fossil fuels worldwide. The work first discusses in detail the different sections in which a power plant with pre-combustion CO2 capture can be divided. For each section, the available technologies with corresponding advantages and disadvantages are presented. Next, the plant lay-outs for natural gas and coal proposed in literature, including heat & mass balances and the economic assessment, are discussed. In general, research activity in pre-combustion decarbonisation for power production focused more on coal than on natural gas-based plant since in the latter case the plant complexity and costs are not competitive with post-combustion CO2 capture, which is a technology on the verge of commercialization. Finally the paper briefly discusses pre-combustion CO2 capture in industry especially those projects where CO2 is captured and stored or used for EOR.

Gas Permeation Study of Carbon Tubular Membrane by Manipulating Carbonization Temperature Profile

Membrane-based separation technology has been widely applied for large-scale industrial CO2 capture due to its lower energy consumption and low pollutant production compared with other conventional techniques. The desirable properties in high performance gas separation membranes involve steps that must carefully be designed and controlled. This study investigates the role of carbonization temperature in the fabrication and performance analysis of carbon membranes prepared from polyimide. A commercial polyimide, Matrimid® 5218, was coated on the surface of ceramic tube to produce supported polymer membrane. The prepared polymer membrane was then carbonized under nitrogen atmosphere to produce supported carbon membrane for CO2/CH4 separation. The resulting carbon tubular membrane separation performance was evaluated using pure gas permeation test. Results showed that the suitable carbonization temperature for Matrimid-based carbon tubular membrane was at 850 °C. The highest selectivity for CO2/CH4 of 82.47 was obtained from carbon tubular membrane prepared at 850 °C.

Relevance of accelerated conditions for the study of monoethanolamine degradation in post‐combustion CO2 capture

AbstractSolvent degradation represents one of the main operational drawbacks of the post‐combustion CO2 capture process. Degradation not only induces additional costs for solvent make‐up, it also impacts the process efficiency and its environmental penalty due to the emission of various degradation products. There is still a gap of knowledge about the influence of process operating conditions on degradation, making it currently impossible to predict the solvent degradation rate in CO2 capture plants. Morever, the reaction mechanisms corresponding to solvent degradation are very slow, significantly complicating its study in industrial units. In the present work, appropriate experimental equipment and analytical methods are developed for accelerating the degradation of monoethanolamine solvents (MEA). The relevance of accelerated conditions is established by comparing artificially degraded solvent samples with degraded solvent samples from industrial CO2 capture pilot plants. Two approaches are evaluated implying either discontinuous or continuous gas feed, this latest being the most representative of industrial degradation. The respective influences of the gas feed composition and the gas‐liquid transfer are evidenced and quantified. Finally, the present study leads to a better understanding of solvent degradation in the CO2 capture process with MEA. More generally, it also evidences that accelerated conditions at laboratory‐scale may provide relevant information for the study of slow phenomena taking place in large‐scale industrial processes. Further works include the development of a kinetic model for MEA solvent degradation and the extension of this methodology to other promising solvents in order to facilitate the operation and large‐scale deployment of CO2 capture.

Bacterial extremo-α-carbonic anhydrases from deep-sea hydrothermal vents as potential biocatalysts for CO2 sequestration

a b s t r a c t Carbonic anhydrase (CA) is an enzyme that rapidly catalyzes the reversible hydration of carbon dioxide (CO2) in aqueous solutions. Recent progresses in CA research suggest that this biocatalyst can be used as an alternative or an additive for chemical CO2 capture, which is considered an essential green route for the reduction of anthropogenic CO2 emissions. However, the facilities in which CA will most likely be used usually operate under high temperature conditions, requiring a highly thermostable CA. Here, we attempted to find and characterize -CAs originated from Perse- phonella marina and Thermovibrio ammonificans, thermophilic Gram-negative bacteria in deep-sea hydrothermal vents. The recombinant -CAs expressed in Escherichia coli showed catalytic efficien- cies better than the previously characterized thermophilic - and -CAs from archaea, and their activities were significantly increased at higher temperatures. Remarkably, these enzymes exhibited outstanding thermostability (stable up to at least 80 ◦C). Through long-term stability tests at 40 ◦C and 60 ◦ C, we discovered that the novel -CA of T. ammonificans might be the most thermostable CA ever characterized. Also, the recombinant CAs successfully accelerated CO2 sequestration in CaCO3, more efficiently than mesophilic bovine CA under high temperature condition. Collectively, these results demonstrate that the -CAs of thermophilic bacteria from deep-sea hydrothermal vents are promising biocatalysts for practical industrial CO2 capture in terms of both activity and stability.

Stability of aqueous amine solutions to thermal and oxidative degradation in the absence and the presence of CO2

The stability to thermal and oxidative degradation of five single amine aqueous solutions (2-amino-2-hydroxymethyl-1,3-propanediol (AHPD), piperazine (Pz), 2-amino-1,3-propanediol (Serinol), 2-amino-2-methyl-1-propanol (AMP) and monoethanolamine (MEA)) and one mixed aqueous solution (AHPD+Pz), in the absence and the presence of CO2, was investigated by high-performance liquid chromatography. The results showed that the presence of O2 and CO2 influenced significantly the degree of thermal degradation. The sterically hindered alkanolamines investigated (AMP and AHPD) were found more resistant to thermal degradation than conventional (unhindered) amines. However, in the absence of CO2, the oxygen degraded them more significantly. The addition of Pz to AHPD solution reduces the AHPD oxidative degradation. It was concluded that AHPD+Pz amine aqueous blend could be a potentially interesting absorbent to replace MEA for industrial CO2 capture applications, especially using membrane contactors.

Ship-in-a-bottle synthesis of amine-functionalized ionic liquids in NaY zeolite for CO2 capture.

CO2 capture on solid materials possesses significant advantages on the operation cost, process for large-scale CO2 capture and storage (CCS) that stimulates great interest in exploring high-performance solid CO2 adsorbents. A ship-in-a-bottle strategy was successfully developed to prepare the [APMIM]Br@NaY host–guest system in which an amine-functionalized ionic liquid (IL), 1-aminopropyl-3-methylimidazolium bromide ([APMIM]Br), was in-situ encapsulated in the NaY supercages. The genuine host-guest systems were thoroughly characterized and tested in CO2 capture from simulated flue gas. It was evidenced the encapsulated ILs are more stable than the bulk ILs. These host–guest systems exhibited superb overall CO2 capture capacity up to 4.94 mmol g−1 and the chemically adsorbed CO2 achieved 1.85 mmol g−1 depending on the [APMIM]Br loading amount. The chemisorbed CO2 can be desorbed rapidly by flushing with N2 gas at 50°C. The optimized [APMIM]Br@NaY system remains its original CO2 capture capacity in multiple cycling tests under prolonged harsh adsorption-desorption conditions. The excellent physicochemical properties and the CO2 capture performance of the host-guest systems offer them great promise for the future practice in the industrial CO2 capture.