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Languages : en
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An innovative, low-cost, and low-energy-consuming carbon dioxide (CO2) capture technology was developed, based on CO2adsorption on a high-capacity and durable carbon sorbent. This report describes the (1) performance of the concept on a bench-scale system; (2) results of parametric tests to determine the optimum operating conditions; (3) results of the testing with a flue gas from coal-fired boilers; and (4) evaluation of the technical and economic viability of the technology. The process uses a falling bed of carbon sorbent microbeads to separate the flue gas into two streams: a CO2 -lean flue gas stream from which> 90% of the CP2 is removed and a pure stream of CO2 that is ready for compression and sequestration. The carbo sorbent microbeads have several unique properties such as high CO2 capacity, low heat of adsorption and desorption (25 to 28 kJ/mole), mechanically robust, and rapid adsorption and desorption rates. The capture of CO2 from the flue gas is performed at near ambient temperatures in whic the sorbent microbeads flow down by gravity counter-current with the up-flow of the flue gas. The adsorbed CO2 is stripped by heating the CO2-loaded sorbent to - 100°C, in contact with low-pressure ( - 5 psig) steam in a section at the bottom of the adsorber. The regenerated sorben is dehydrated of adsorbed moisture, cooled, and lifted back to the adsorber. The CO2 from the desorber is essentially pure and can be dehydrated, compressed, and transported to a sequestration site. Bench-scale tests using a simulated flue gas showed that the integrated system can be operated to provide> 90% CO2 capture from a 15% CO2 stream in the adsorber and produce> 98% CO2 at the outlet of the stripper. Long-term tests (1,000 cycles) showed that the system can be operated reliably without sorbent agglomeration or attrition. The bench-scale reactor was also operated using a flue gas stream from a coal-fired boil at the University of Toledo campus for about 135 h, comprising 7,000 cycles of adsorption and desorption using the desulfurized flue gas that contained only 4.5% v/v CO2. A capture efficiency of 85 to 95% CO2 was achieved under steady-state conditi ons. The CO2 adsorption capacity did not change significantly during the field test, as determined from the CO2 adsorptio isotherms of fresh and used sorbents. The process is also being tested using the flue gas from a PC-fired power plant at the National Carbon Capture Center (NCCC), Wilsonville, AL. The cost of electricity was calculated for CO2 capture using the carbon sorbent and compared with the no-CO2 capture and CO2 capture with an amine-based system. The increase i the levelized cost of electricity (L-COE) is about 37% for CO2 capture using the carbon sorbent in comparison to 80% for an amine-based system, demonstrating the economic advantage of C capture using the carbon sorbent. The 37% increase in the L-COE corresponds to a cost of capture of $30/ton of CO2, including compression costs, capital cost for the capture system, and increased plant operating and capital costs to make up for reduced plant efficiency. Preliminary sensitivity analyses showed capital costs, pressure drops in the adsorber, and steam requirement for the regenerator are the major variables in determining the cost of CO2 capture. The results indicate that further long-term testing with a flue gas from a pulverized coal fired boiler should be performed to obtain additional data relating to the effects of flue gas contaminants, the ability to reduce pressure drop by using alternate structural packing, and the use of low-cost construction materials.
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Languages : en
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Book Description
An innovative, low-cost, and low-energy-consuming carbon dioxide (CO2) capture technology was developed, based on CO2adsorption on a high-capacity and durable carbon sorbent. This report describes the (1) performance of the concept on a bench-scale system; (2) results of parametric tests to determine the optimum operating conditions; (3) results of the testing with a flue gas from coal-fired boilers; and (4) evaluation of the technical and economic viability of the technology. The process uses a falling bed of carbon sorbent microbeads to separate the flue gas into two streams: a CO2 -lean flue gas stream from which> 90% of the CP2 is removed and a pure stream of CO2 that is ready for compression and sequestration. The carbo sorbent microbeads have several unique properties such as high CO2 capacity, low heat of adsorption and desorption (25 to 28 kJ/mole), mechanically robust, and rapid adsorption and desorption rates. The capture of CO2 from the flue gas is performed at near ambient temperatures in whic the sorbent microbeads flow down by gravity counter-current with the up-flow of the flue gas. The adsorbed CO2 is stripped by heating the CO2-loaded sorbent to - 100°C, in contact with low-pressure ( - 5 psig) steam in a section at the bottom of the adsorber. The regenerated sorben is dehydrated of adsorbed moisture, cooled, and lifted back to the adsorber. The CO2 from the desorber is essentially pure and can be dehydrated, compressed, and transported to a sequestration site. Bench-scale tests using a simulated flue gas showed that the integrated system can be operated to provide> 90% CO2 capture from a 15% CO2 stream in the adsorber and produce> 98% CO2 at the outlet of the stripper. Long-term tests (1,000 cycles) showed that the system can be operated reliably without sorbent agglomeration or attrition. The bench-scale reactor was also operated using a flue gas stream from a coal-fired boil at the University of Toledo campus for about 135 h, comprising 7,000 cycles of adsorption and desorption using the desulfurized flue gas that contained only 4.5% v/v CO2. A capture efficiency of 85 to 95% CO2 was achieved under steady-state conditi ons. The CO2 adsorption capacity did not change significantly during the field test, as determined from the CO2 adsorptio isotherms of fresh and used sorbents. The process is also being tested using the flue gas from a PC-fired power plant at the National Carbon Capture Center (NCCC), Wilsonville, AL. The cost of electricity was calculated for CO2 capture using the carbon sorbent and compared with the no-CO2 capture and CO2 capture with an amine-based system. The increase i the levelized cost of electricity (L-COE) is about 37% for CO2 capture using the carbon sorbent in comparison to 80% for an amine-based system, demonstrating the economic advantage of C capture using the carbon sorbent. The 37% increase in the L-COE corresponds to a cost of capture of $30/ton of CO2, including compression costs, capital cost for the capture system, and increased plant operating and capital costs to make up for reduced plant efficiency. Preliminary sensitivity analyses showed capital costs, pressure drops in the adsorber, and steam requirement for the regenerator are the major variables in determining the cost of CO2 capture. The results indicate that further long-term testing with a flue gas from a pulverized coal fired boiler should be performed to obtain additional data relating to the effects of flue gas contaminants, the ability to reduce pressure drop by using alternate structural packing, and the use of low-cost construction materials.
Author: De-en Jiang
Publisher: John Wiley & Sons
ISBN: 1119091179
Category : Science
Languages : en
Pages : 397
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Covers a wide range of advanced materials and technologies for CO2 capture As a frontier research area, carbon capture has been a major driving force behind many materials technologies. This book highlights the current state-of-the-art in materials for carbon capture, providing a comprehensive understanding of separations ranging from solid sorbents to liquid sorbents and membranes. Filled with diverse and unconventional topics throughout, it seeks to inspire students, as well as experts, to go beyond the novel materials highlighted and develop new materials with enhanced separations properties. Edited by leading authorities in the field, Materials for Carbon Capture offers in-depth chapters covering: CO2 Capture and Separation of Metal-Organic Frameworks; Porous Carbon Materials: Designed Synthesis and CO2 Capture; Porous Aromatic Frameworks for Carbon Dioxide Capture; and Virtual Screening of Materials for Carbon Capture. Other chapters look at Ultrathin Membranes for Gas Separation; Polymeric Membranes; Carbon Membranes for CO2 Separation; and Composite Materials for Carbon Captures. The book finishes with sections on Poly(amidoamine) Dendrimers for Carbon Capture and Ionic Liquids for Chemisorption of CO2 and Ionic Liquid-Based Membranes. A comprehensive overview and survey of the present status of materials and technologies for carbon capture Covers materials synthesis, gas separations, membrane fabrication, and CO2 removal to highlight recent progress in the materials and chemistry aspects of carbon capture Allows the reader to better understand the challenges and opportunities in carbon capture Edited by leading experts working on materials and membranes for carbon separation and capture Materials for Carbon Capture is an excellent book for advanced students of chemistry, materials science, chemical and energy engineering, and early career scientists who are interested in carbon capture. It will also be of great benefit to researchers in academia, national labs, research institutes, and industry working in the field of gas separations and carbon capture.
Author: Mohammad Reza Rahimpour
Publisher: Woodhead Publishing
ISBN: 0128227583
Category : Science
Languages : en
Pages : 574
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Book Description
Advances in Carbon Capture reviews major implementations of CO2 capture, including absorption, adsorption, permeation and biological techniques. For each approach, key benefits and drawbacks of separation methods and technologies, perspectives on CO2 reuse and conversion, and pathways for future CO2 capture research are explored in depth. The work presents a comprehensive comparison of capture technologies. In addition, the alternatives for CO2 separation from various feeds are investigated based on process economics, flexibility, industrial aspects, purification level and environmental viewpoints. - Explores key CO2 separation and compare technologies in terms of provable advantages and limitations - Analyzes all critical CO2 capture methods in tandem with related technologies - Introduces a panorama of various applications of CO2 capture
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Languages : en
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In chapter 1, the studies focused on the development of novel sorbents for reducing the carbon dioxide emissions at high temperatures. Our studies focused on cesium doped CaO sorbents with respect to other major flue gas compounds in a wide temperature range. The thermo-gravimetric analysis of sorbents with loadings of CaO doped on 20 wt% cesium demonstrated high CO2 sorption uptakes (up to 66 wt% CO2/sorbent). It is remarkable to note that zero adsorption affinity for N2, O2, H2O and NO at temperatures as high as 600 C was observed. For water vapor and nitrogen oxide we observed a positive effect for CO2 adsorption. In the presence of steam, the CO2 adsorption increased to the highest adsorption capacity of 77 wt% CO2/sorbent. In the presence of nitrogen oxide, the final CO2 uptake remained same, but the rate of adsorption was higher at the initial stages (10%) than the case where no nitrogen oxide was fed. In chapter 2, Ca(NO3)2 · 4H2O, CaO, Ca(OH)2, CaCO3, and Ca(CH3COO)2 · H2O were used as precursors for synthesis of CaO sorbents on this work. The sorbents prepared from calcium acetate (CaAc2-CaO) resulted in the best uptake characteristics for CO2. It possessed higher BET surface area and higher pore volume than the other sorbents. According to SEM images, this sorbent shows 'fluffy' structure, which probably contributes to its high surface area and pore volume. When temperatures were between 550 and 800 C, this sorbent could be carbonated almost completely. Moreover, the carbonation progressed dominantly at the initial short period. Under numerous adsorption-desorption cycles, the CaAc2-CaO demonstrated the best reversibility, even under the existence of 10 vol % water vapor. In a 27 cyclic running, the sorbent sustained fairly high carbonation conversion of 62%. Pore size distributions indicate that their pore volume decreased when experimental cycles went on. Silica was doped on the CaAc2-CaO in various weight percentages, but the resultant sorbent did not exhibit better performance under cyclic operation than those without dopant. In chapter 3, the Calcium-based carbon dioxide sorbents were made in the gas phase by flame spray pyrolysis (FSP) and compared to the ones made by standard high temperature calcination (HTC) of selected calcium precursors. The FSP-made sorbents were solid nanostructured particles having twice as large specific surface area (40-60 m2/g) as the HTC-made sorbents (i.e. from calcium acetate monohydrate). All FSP-made sorbents showed high capacity for CO2 uptake at high temperatures (773-1073 K) while the HTC-made ones from calcium acetate monohydrate (CaAc2 · H2O) demonstrated the best performance for CO2 uptake among all HTC-made sorbents. At carbonation temperatures less than 773 K, FSP-made sorbents demonstrated better performance for CO2 uptake than all HTC-made sorbents. Above that, both FSP-made, and HTC-made sorbents from CaAc2 · H2O exhibited comparable carbonation rates and maximum conversion. In multiple carbonation/decarbonation cycles, FSP-made sorbents demonstrated stable, reversible and high CO2 uptake capacity sustaining maximum molar conversion at about 50% even after 60 such cycles indicating their potential for CO2 uptake. In chapter 4 we investigated the performance of CaO sorbents with dopant by flame spray pyrolysis at higher temperature. The results show that the sorbent with zirconia gave best performance among sorbents having different dopants. The one having Zr to Ca of 3:10 by molar gave stable performance. The calcium conversion around 64% conversion during 102-cycle operations at 973 K. When carbonation was performance at 823 K, the Zr/Ca sorbent (3:10) exhibited stable performance of 56% by calcium molar conversion, or 27% by sorbent weight, both of which are less than those at 973 K as expected. In chapter 5 we investigated the performance of CaO sorbents by flame spray pyrolysis at higher temperature with much shorter duration period. Stable high conversions were attained after 40 cycles The results show that the sorbent could reach high CO2 capture capacity, be completely regenerated in short time and be quite stable even at these severe conditions. Several studies were devoted to identify sorbents which could effectively capture CO2 while survive in SO2 atmosphere. From the group of sorbents we checked, a couple of sorbents showed very promising behavior, namely CO2 uptakes higher than 60% (wt/wt sorbent) while they acquired higher than 95% of their original activity/performance characteristics in a short period of time.
Author: Di Wu
Publisher:
ISBN:
Category : Carbon dioxide
Languages : en
Pages : 157
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"An innovative preparation method is developed to highly improve the carbon dioxide capture capacity of the silica sorbents. In the previously used sorbent treatment method, free hydroxyl groups of silica available for further reaction are obtained by silica dehydration at high temperature. This new approach, however, grafts tetraethylenepentamine (TEPA) onto silica surface directly via incipient wetness impregnation (IWI) of TEPA/ethanol solutions at room temperature. The CO2 adsorption/desorption performance of the catalysts is studied by Diffused Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and Mass Spectrometer (MS) spectroscopy both qualitatively and quantitatively. The concentration of TEPA/ethanol solutions influences the deposit process of pentamine molecules onto silica particles by controlling the concentration differential of TEPA between the bulk solution and the surface layer. Samples treated with more concentrated solutions had higher maximum carbon dioxide adsorption values, calculated from the calibrated CO2 desorption peak area of MS spectra. The loading amount of solution also affects the mass transfer rate and equilibrium of TEPA. After the concentration is equilibrated between the bulk and the surface, the system lost the concentration gradient between bulk solution and silica surfaces, excessive pentamine solution removes the grafted pentamine molecules, and makes the carbon dioxide capture capacity curve drop from the peak point. The 0.03g silica treated by 2%, 10% and 20% TEPA/EtOH solution got the CO2 adsorption capacity of 1545.03, 4590.28 and 7674.99 [mu]mol/g-sorbent, respectively. Two pretreatment methods of silica sorbents, ethanol pretreatment and carbon dioxide pretreatment, are used to further enhance the adsorption performance. In the former pretreatment, ethanol solvent is injected before each injection of TEPA solution, and in the latter, TEPA solution is injected in the atmosphere of a carbon dioxide gas. The principles behind these pretreatments underlie mass and momentum transfer processes. After the injection of TEPA/ethanol solution, the TEPA layer on silica surface becomes more and more concentrated with the solvent evaporation. Pores and channels are likely to be blocked by the high viscous TEPA on silica surfaces. Sufficient solvent molecules in the ethanol pretreatment help more than keep the concentration gradient between the bulk and surface and maintain a driving force to deposit the TEPA onto silica surfaces, an appropriate viscosity assists TEPA molecules diffuse deeper. 0.03g silica at the loading of 200 [mu]l, 20% TEPA/EtOH solution, the maximum CO2 adsorption capacity is 8362.36 [mu]mol/g-sorbent with Ethanol pretreatment approach. The grafted pentamine molecules on silica surface can form inter-molecular H-bonds, which consume the functional amine groups and reduce the surface area available for CO2 capture. Carbon dioxide was used to protect these free NH groups in the carbon dioxide pretreatment. DRIFTS and MS spectroscopy analysis shows either way gives the sorbent a higher carbon dioxide adsorption capacity than those without any pretreatment. 0.03g silica at the loading of 250 [mu]l, 20% TEPA/EtOH solution, the maximum CO2 adsorption capacity is 9455.58 [mu]mol/g-sorbent with CO2 pretreatment approach."--Abstract.
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Languages : en
Pages : 101
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Author: M. Mercedes Maroto-Valer
Publisher:
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Languages : en
Pages :
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This research program focused on the development of fly ash derived sorbents to capture CO{sub 2} from power plant flue gas emissions. The fly ash derived sorbents developed represent an affordable alternative to existing methods using specialized activated carbons and molecular sieves, that tend to be very expensive and hinder the viability of the CO{sub 2} sorption process due to economic constraints. Under Task 1 'Procurement and characterization of a suite of fly ashes', 10 fly ash samples, named FAS-1 to -10, were collected from different combustors with different feedstocks, including bituminous coal, PRB coal and biomass. These samples presented a wide range of LOI value from 0.66-84.0%, and different burn-off profiles. The samples also spanned a wide range of total specific surface area and pore volume. These variations reflect the difference in the feedstock, types of combustors, collection hopper, and the beneficiation technologies the different fly ashes underwent. Under Task 2 'Preparation of fly ash derived sorbents', the fly ash samples were activated by steam. Nitrogen adsorption isotherms were used to characterize the resultant activated samples. The cost-saving one-step activation process applied was successfully used to increase the surface area and pore volume of all the fly ash samples. The activated samples present very different surface areas and pore volumes due to the range in physical and chemical properties of their precursors. Furthermore, one activated fly ash sample, FAS-4, was loaded with amine-containing chemicals (MEA, DEA, AMP, and MDEA). The impregnation significantly decreased the surface area and pore volume of the parent activated fly ash sample. Under Task 3 'Capture of CO{sub 2} by fly ash derived sorbents', sample FAS-10 and its deashed counterpart before and after impregnation of chemical PEI were used for the CO{sub 2} adsorption at different temperatures. The sample FAS-10 exhibited a CO{sub 2} adsorption capacity of 17.5mg/g at 30 C, and decreases to 10.25mg/g at 75 C, while those for de-ashed counterpart are 43.5mg/g and 22.0 mg/g at 30 C and 75 C, respectively. After loading PEI, the CO{sub 2} adsorption capacity increased to 93.6 mg/g at 75 C for de-ashed sample and 62.1 mg/g at 75 C for raw fly ash sample. The activated fly ash, FAS-4, and its chemical loaded counterparts were tested for CO{sub 2} capture capacity. The activated carbon exhibited a CO{sub 2} adsorption capacity of 40.3mg/g at 30 C that decreased to 18.5mg/g at 70 C and 7.7mg/g at 120 C. The CO{sub 2} adsorption capacity profiles changed significantly after impregnation. For the MEA loaded sample the capacity increased to 68.6mg/g at 30 C. The loading of MDEA and DEA initially decreased the CO{sub 2} adsorption capacity at 30 C compared to the parent sample but increased to 40.6 and 37.1mg/g, respectively, when the temperature increased to 70 C. The loading of AMP decrease the CO{sub 2} adsorption capacity compared to the parent sample under all the studied temperatures. Under Task 4 'Comparison of the CO{sub 2} capture by fly ash derived sorbents with commercial sorbents', the CO{sub 2} adsorption capacities of selected activated fly ash carbons were compared to commercial activated carbons. The CO{sub 2} adsorption capacity of fly ash derived activated carbon, FAS-4, and its chemical loaded counterpart presented CO{sub 2} capture capacities close to 7 wt%, which are comparable to, and even better than, the published values of 3-4%.
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Publisher: ScholarlyEditions
ISBN: 1481676741
Category : Science
Languages : en
Pages : 810
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Book Description
Inorganic Carbon Compounds—Advances in Research and Application: 2013 Edition is a ScholarlyBrief™ that delivers timely, authoritative, comprehensive, and specialized information about ZZZAdditional Research in a concise format. The editors have built Inorganic Carbon Compounds—Advances in Research and Application: 2013 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about ZZZAdditional Research in this book to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Inorganic Carbon Compounds—Advances in Research and Application: 2013 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Author: Jun Wang
Publisher:
ISBN:
Category : Carbon
Languages : en
Pages : 562
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Global warming resulted from greenhouse gases emission has received a widespread attention. Among the greenhouse gases, Co2 contributes more than 60% to global warming due to its huge emission amount. The flue gas contains about 15% CO2 with N2 as the balance. If CO2 can be separated from flue gas, the benefit is not only reducing the global warming effect, but also producing pure CO2 as a very useful industry raw material. Substantial progress is urgent to be achieved in an industrial process. Moreover, energy crisis is one of the biggest challenges for all countries due to the short life of fossil fuels, such as, petroleum will run out in 50 years and coal will run out in 150 years according to today's speed. Moreover, the severe pollution to the environment caused by burning fossil fuels requires us to explore sustainable, environment-friendly, and facile energy sources. Among several alternative energy sources, natural gas is one of the most promising alternative energy sources due to its huge productivity, abundant feed stock, and ease of generation. In order to realize a substantial adsorption process in industry, synthesis of new absorbents or modification of existing adsorbent with improved properties has become the most critical issue. This dissertation reports systemic characterization and development of five serials of novel adsorbents with advanced adsorption properties. In chapter 2, nitrogen-doped Hypercross-linking Polymers (HCPs) have been synthesized successfully with non-carcinogenic chloromethyl methyl ether (CME) as the cross-linking agent within a single step. Texture properties, surface morphology, CO2/N2 selectivity, and adsorption heat have been presented and demonstrated properly. A comprehensive discussion on factors that affect the CO2 adsorption and CO2/N2 separation has also been presented. It was found that high micropore proportion and N-content could effectively enhance CO2 uptake and CO2/N2 separation selectivity. In chapter 3, a new series of oxygen-doped ACs were synthesized from polyfuran. Different factors that affect the AC formation were investigated, and two kinds of porogens (ZnCL2 and KOH) and two active temperatures (600 and 800 °C) were tested. At 298K and 1bar, an excellent selectivity for separating CO2/N2 (41.7) and Co2/CH4 (6.8) gas mixture pairs was obtained on the PF-600 KOH. A breakthrough simulation was also performed to demonstrate the potential of industrial applications. The PF-600 KOH sample showed the best separation result in the simulated adsorption breakthrough as well. In chapter 4, quinone and hydroquinone on the surface of PF-600 ZnCL2 were integrated. Significantly pore size shrinkage, improved CO2/N2 and CO2/CH4 IAST selectivity were observed, which is 58.7% and 28.4% higher than pristine porous carbon at 298 K and 1 atm, respectively. In addition, transient breakthrough simulations for CO2/CH4/N2 binary mixtures were conducted in order to demonstrate the good separation performance in fixed bed adsorbers. In chapter 5, a novel nitrogen doped polymer poly(2-phenyl-1,3,6,8-tetraazacyclodecane) will be used as the precursor to produce microporous N-doped activated carbons. Three activation temperatures (600, 700, and 800 °C) has been investigated with KOH as the porogen. High nitrogen content has been remained in the resultant carbon materials. Improved CO2 adsorption capacity and selectivites for the separation of CO2/CH4/N2 binary gas mixtures were achieved by the carbon adsorbents due to their N-containing groups, narrow pore size distribution, and large specific surface area. In chapter 6, MOF-derived activated carbons are developed from MIL-100(Al) as hard-template. Direct carbonization of MIL-100, MIL-100(Al)/F-127 composite, and MIL-100(Al)/KOH mixture has been investigated. Pore structure and surface morphology have been demonstrated. CO2/CH4/N2 binary selectivity, adsorption heats, and kinetic selectivity have been calculated. Breakthrough simulation has been conducted to mimic industrial application. We found that resultant carbons showed better CO2 capture ability and selectivity than parental MIL-100(Al).
Author: Bryce Dutcher
Publisher:
ISBN: 9781339054704
Category : Amines
Languages : en
Pages : 171
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Strong evidence exists suggesting that anthropogenic emissions of CO2 have been contributing to global climate change. Because of this, it becomes imperative to mitigate anthropogenic CO2. Unfortunately, the best available current technology for CO2 capture, amine scrubbing, is a costly operation due to the energy required for regeneration of the amine. Solid Na2CO3 is considered a potential alternative to amine scrubbing due to its low heat of reaction, but it is not commercially viable due to its low reaction rates for both CO2 sorption and desorption. In order to increase the reaction rate, this project studied nanoporous FeOOH and TiO(OH)2 as supporting materials for Na2CO3. Because regeneration of the sorbent is the most energy-intensive step when using Na2CO3 for CO2 sorption, this project focused on the decomposition of NaHCO3, which is equivalent to CO2 desorption. FeOOH and TiO(OH)2 are shown to be thermally stable with and without the presence of NaHCO3 at temperatures necessary for sorption and regeneration, up to about 200°C. More significantly, it is observed that these supports not only increase the surface area of NaHCO3, but they also have a catalytic effect on the decomposition of NaHCO3. For example, the rate constant for the decomposition of NaHCO3 at 120 °C is increased from 0.02 min-1 without a support to 0.46 min-1 with 50 wt.% FeOOH and 0.39 min-1 with 50 wt.% TiO(OH)2. The activation energy is reduced from 80 kJ/mol without a support to 44 kJ/mol with 50 wt.% FeOOH and to 35 kJ/mol with 50 wt.% TiO(OH)2. This increase in reaction rate could translate into a substantial decrease in the cost of using Na2CO3 for CO2 capture. Amine-functionalized sorbents, like solid Na2CO3, have potentially lower energy requirements than aqueous amines due to the absence of bulk water, and they retain many of the advantages of aqueous amines such as high reaction rates and high CO2 capacity. Here, the structure and stability of a recently developed amine functionalized silica sorbent is investigated.
