Download or read book Preparation and Modification of Amine functionalized Solid Sorbents for CO2 Adsorption and SO2 Resistance written by Sihan Wang and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Over loading of CO2 emission has been a severe environment problem and the fact of greenhouse issue has become a huge impact to our daily life. The largest and inevitable emission of CO2 gas is the coal-fired power plant, and the most commonly used CO2 capture sorbent is liquid amine. However, there are lots of inconvenience of using liquid amine including equipment corrosion, high regeneration energy and slow diffusion of the CO2 gas, which would cost the capture procedure a huge amount of expense. Nevertheless, the solid sorbent is in face of the issue that the capture capacities and SO2 resistance is really low. So in this research, the modified amine-functionalized solid sorbents for CO2 adsorption and SO2 resistance have been created. The problem of lower CO2 capture capacity was modified by double impregnation, and the issue of lower heat transfer rate was improved by adding heat transfer agent during pelletization. The characterization of the sorbent and pellets capture behavior was done by CO2 capture weight method and in-situ DRIFT spectra, and the SO2 resistance behavior has also been discussed with EDS mapping and quantification.

Download or read book CO2 and SO2 Capture by Aromatic and Aliphatic Amine Sorbents written by Ernesto Silva Mojica and published by . This book was released on 2011 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emissions of CO2 to the atmosphere have rapidly increased in the last decades due to the industrialization and the increasing energy demand. Due to the potential effect that CO2 has as global warmer, industrialized and emerging countries are putting efforts on developing technologies to reduce emissions. Coal fired power plants produce 55% of U.S. electricity and more than 33% of global CO2 emissions, representing the largest stationary source of CO2. As a co-product of the combustion process of sulfur-containing coal, SO2 is produced and represents between 0.2 and 0.3 v% of the power plant flue gas composition. SO2 is a serious pollutant, precursor of the acid rain and particulate materials. The release of SO2 to the atmosphere can cause respiratory diseases and destruction of eco-systems. Some existing CO2 capture technologies are inefficient to be applied in power plants due to the large flow rates and high concentration of CO2 in the flue gas. Other technologies such as the liquid amine process are not economically viable because the energy requirements for operation and regeneration are excessive. In addition those processes cause rapid corrosion to the equipment. The adsorption on solid sorbents is potentially the most suitable process for the treatment of flue gas from power plants. The development of solid sorbents by functionalization of solid supports with amine functional groups has been recently studied. The goals during the sorbent development are (i) a high CO2 selectivity and adsorption capacity, (ii) the long term stability and cycle life, (iii) resistivity toward thermal and oxidative degradation, (iv) resistance to SO2 and (iv) low cost. In this thesis, the resistance of aliphatic amine and aromatic anime sorbents towards SO2 was studied by in-situ infrared spectroscopy (IR) and mass spectrometry (MS). An operational condition to improve the CO2 adsorption capacity of an amine sorbent was also studied by introducing H2O in the flue gas. The hypothesis included the use of an aromatic amine to prepare a low basicity sorbent for SO2 capture and to reduce the SO2 poisoning on a CO2 capture sorbent. In addition, it is thought that the presence of H2O in the flue gas improves the adsorption capacity of an amine sorbent due to the formation of different adsorbed species. The IR and MS results showed that the aromatic amine sorbent has a weak adsorption capacity of CO2 and SO2, leading to CO2 capture processes at low temperature. SO2 strongly adsorbs on the aliphatic amine sorbent, causing accumulation of sulfate and sulfite species and reducing the availability of amine sites for CO2 adsorption. The performance of CO2 capture in simulated practical conditions showed the improvement in capture capacity of a sorbent by more than 60% when the flue gas is saturated with H2O.

Download or read book Post combustion Carbon Dioxide Capture Using Amine Functionalized Solid Sorbents written by Nikhil Mittal and published by . This book was released on 2013 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is divided into two parts: (1) Synthesis of amine functionalized adsorbents using grafting technique for post-combustion CO[subscript 2] capture, (2) Performance evaluation of structured bed configuration with straight gas flow channels using amine impregnated adsorbent for post-combustion CO[subscript 2] capture. Brief description of each part is given below: (1)N-(3-trimethoxysilylpropyl)diethylenetriamine (DAEAPTS) grafted SBA-15 adsorbents were synthesized for CO[subscript 2] capture. The adsorption of CO[subscript 2] on the amine-grafted sorbents was measured by thermogravimetric method over a CO[subscript 2] partial pressure range of 8-101.3 kPa and a temperature range of 25-105 °C under atmospheric pressure. The optimal amine loaded SBA-15 adsorbent was examined for multi-cycle stability and adsorption/desorption kinetics. (2)The performance of structured bed and packed bed configurations for post-combustion CO[subscript 2] capture was evaluated using PEI impregnated SBA-15 adsorbent. The effect of adsorption temperature (25-90 °C), adsorption /desorption kinetics and multi-cycle stability was studied in both structured and packed bed configurations.

Download or read book Development of Polymeric SO2 Resistant Coating for Solid Amine Sorbent written by Hailiang Jin and published by . This book was released on 2015 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: The impurities in flue gas from coal fire power plant such as SO2, could poison CO2 sorbent due to its strong acidity. To reinforce the stability of sorbent in presence of SO2, polymeric SO2-resistant coating was developed and characterized by in-situ FTIR spectroscopy. This coating was prepared by crosslinking poly(ethylenemine) with an epoxy and applied to CQA-12, a solid amine sorbent. The effect of the epoxy composition on the stability and adsorption / desorption kinetics of the coated sorbent was investigated by FTIR and mass spectrometry. The results revealed that this polymeric coating enhanced the resistance to SO2 poisoning, thus the multi-cyclic stability of the sorbent in presence of SO2, by converting the amine sites to secondary and tertiary amine. Though it reduced the initial CO2 capture capacity due to blocked amine sites. Increased amount of epoxy was found to strengthen the SO2 resistance. The FTIR spectra denoted that the introduction of epoxy increased the ratio of weakly adsorbed CO2 to strongly adsorbed CO2, i.e., reduced the binding strength of amine/CO2.

Download or read book Synthesis and Carbon Dioxide Adsorption Properties of Amine Modified Particulate Silica Aerogel Sorbents written by Nick Linneen and published by . This book was released on 2014 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Post-combustion carbon capture is a viable option for reducing CO2 greenhouse gas emissions, and one potentially promising technology for this route is adsorption using chemically and physically based sorbents. A number of exceptional CO2 sorbents materials have been prepared including metal organic frameworks, zeolites, and carbon based materials. One particular group of capable materials are amine based solid sorbents that has shown to possess high adsorption capacities and favorable adsorption kinetics. A key variable in the synthesis of an amine based sorbent is the support which acts as the platform for the amine modification. Aerogels, due to their high porosities and surface areas, appear to be a promising support for an amine modified CO2 sorbent. Therefore, in order to develop a commercially viable CO2 sorbent, particulate aerogels manufactured by Cabot Corporation through an economical and proprietary ambient drying process were modified with amines using a variety of functionalization methods. Two methods of physical impregnation of the amino polymer TEPA were performed in order to observe the performance as well as understand the effects of how the TEPA distribution is affected by the method of introduction. Both samples showed excellent adsorption capacities but poor cyclic stability for lack of any covalent attachment. Furthermore the method of TEPA impregnation seems to be independent on how the polymer will be distributed in the pore space of aerogel. The last two methods utilized involved covalently attaching amino silanes to the surface silanols of the aerogel. One method was performed in the liquid phase under anhydrous and hydrous conditions. The materials developed through the hydrous method have much greater adsorption capacities relative to the anhydrous sample as a result of the greater amine content present in the hydrous sample. Water is another source of silylation where additional silanes can attach and polymerize. These samples also possessed stable cyclic stability after 100 adsorption/regeneration cycles. The other method of grafting was performed in the gas phase through ALD. These samples possessed exceptionally high amine efficiencies and levels of N content without damaging the microstructure of the aerogel in contrast to the liquid phase grafted sorbents.

Download or read book SO2 Resistant Immobilized Amine Sorbents for CO2 Capture written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The solid amine sorbent for CO2 capture process has advantages of simplicity and low operating cost compared to the MEA (monoethanolamine) process. Solid amine sorbents reported so far suffered from either low CO2 capture capacity or low stability in the flue gas environment. This project is aimed at developing a SO2-resistant solid amine sorbent for capturing CO2 from coal-fired power plants with SCR/FGD which emits SO2 ranging from 15 to 30 ppm and NO ranging from 5 to 10 ppm. The amine sorbent we developed in a previous project degraded rapidly with 65% decrease in the initial capture capacity in presence of 1% SO2. This amine sorbent was further modified by coating with polyethyleneglycol (PEG) to increase the SO2-resistance. Polyethylene glycol (PEG) was found to decrease the SO2-amine interaction, resulting in the decrease in the maximum SO desorption temperature (Tmax) of amine sorbent. The PEG-coated amine sorbent exhibited higher stability with only 40% decrease in the initial capture capacity compared to un-coated amine sorbents. The cost of the solid amine sorbent developed in this project is estimated to be less than $7.00/lb; the sorbent exhibited CO2 capture capacity more than 2.3 mmol/g. The results of this study provided the scientific basis for further development of SO2-resistant sorbents.

Download or read book Synthesis and Characterization of Alkylamine Functionalized Metal Organic Frameworks as Adsorbents for Carbon Dioxide written by Thomas Michael McDonald and published by . This book was released on 2015 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work herein describes an investigation of metal-organic frameworks as adsorbents for selectively removing carbon dioxide (CO2) from low-pressure gas mixtures. Metal-organic frameworks are permanently porous, crystalline solid phase materials composed of organic molecules connected together by metal-based nodes into ordered structures. Generally exhibiting very high gravimetric surface areas, the pore surfaces of metal-organic frameworks can be rationally designed to allow for highly specific interactions between the adsorbent and guest species. Through chemical modifications of the pore surfaces, metal-organic frameworks were designed to adsorb CO2 over other small molecules. Chapter 1 begins with background information on carbon capture and sequestration (CCS) and the role it can potentially play in slowing anthropogenic CO2 emissions. An analysis of desirable metal-organic frameworks properties is presented along with a summary of the most significant work in the field of developing new metal-organic frameworks as CO2 adsorbents. Finally, a summary of amine-functionalized solid adsorbents that have directly influenced the synthesis and characterization methods reported in this investigation is presented. Chapter 2 reports the synthesis and characterization of the metal-organic framework mmen-CuBTTri. At the time it was first synthesized, mmen-CuBTTri exhibited some of the best CO2 adsorption properties of any metal-organic framework, including the highest selectivity for CO2 over N2 yet measured. The sorbent was the first to demonstrate that aliphatic amines could significantly improve the CO2 adsorption properties of metal-organic frameworks with open metal sites. Furthermore, despite an enthalpy of CO2 adsorption of nearly -100 kJ/mol at zero coverage, it was shown that the sorbent could be effectively cycled with modest temperature swings. Chapter 3 reports the original synthesis and characterization of mmen-Mg2(dobpdc). Utilizing the same diamine as the sorbent in Chapter 2, it was demonstrated that the nature of metal-organic framework support, and not just the amine functional groups, affects the CO2 adsorption properties. In this case, the high density of amines within the pores resulted in a material that could effectively remove CO2 at very low concentrations; it was the first metal-organic framework studied for its ability to remove CO2 directly from air. Furthermore, mmen-Mg2(dobpdc) was the first amine-functionalized solid sorbent to exhibit steps in its pure component CO2 isotherm. Finally, it was shown that the adsorption properties of the material, especially the regeneration energy, make it competitive with aqueous amine solutions. Chapter 4 builds upon the work of Chapter 3. The adsorption mechanism of mmen-Mg2(dobpdc), which was studied by infrared spectroscopy, solid state NMR spectroscopy, and in situ powder X-ray diffraction measurements was revealed to be a previously unprecedented cooperative insertion mechanism. The origin of the unusual isotherm steps was revealed to be a phase transition of the amines attached to the pore surface. In Chapter 4, a method of controlling the position of isotherm steps is described. Finally, the superior carbon capture characteristics of phase change adsorbents are enumerated. Chapter 5 is a departure from the previous chapters and describes a simple and convenient method of utilizing a commercially available thermogravimetric analyzer to assess the porosity and activation conditions of metal-organic frameworks. The importance of identifying proper activation is discussed and a suggested protocol for researchers to use is given. Lastly, the ability of the method to improve the reported gas adsorption properties of the metal-organic framework Mn-BTT is reported.

Download or read book In situ Infrared Study of Amine Functionalized Polymer Sorbents for CO2 Capture written by Lin Pan and published by . This book was released on 2015 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emissions of CO2 act as a major source for global climate change in today's society and it mainly comes from coal-fired power plants. There are several techniques for CO2 capture such as liquid amine process, membrane separation, chemical looping and solid sorbent process. In my study, the solid amine sorbents are used for CO2 capture due to it can reduce the regeneration energy, avoid the corrosion of equipment and increase the CO2 adsorption and desorption rate compared with liquid amine process. The porous polyvinyl alcohol (PVA) support was synthesized by using glutaraldehyde (GA) as a cross-linking agent and phase inversed in acetone. Polyethyleneimine (PEI) and tetraethylenepentamine (TEPA) were impregnated on PVA support respectively for CO2 adsorption. The performance of sorbents were tested by CO2 capture capacity through weight change method and the nature of CO2 adsorption on sorbents with different amine content (N %) were characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), as well as the formation and desorption of CO2 adsorbed species from fresh and degraded sorbents. Besides, the effect of antioxidant in inhibiting the degradation was also studied.

Download or read book In Situ Infrared and Mass Spectroscopic Study on Amine immobilized Silica for CO2 Capture written by Jak Tanthana and published by . This book was released on 2011 with total page 2005 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rapid increase in atmospheric CO2 has become a major environmental concern in recent years. Coal-fired power plants, releasing flue gas containing CO2, account for approximately 30% of total CO2 emissions worldwide. Solid amine sorbents such as amine immobilized on silica (SiO2) has gained significant consideration for capturing CO2 from flue gas due to its lower operation cost and equipment corrosion compared to existing liquid amine process. The -NH2 functional group of these solid amine sorbents binds CO2 through acid-base interactions, allowing CO2 to adsorb and desorb at temperatures in the range of the flue gas operating conditions. Studies have shown that the solid amine sorbents can initially adsorb CO2 at the economical level compared to that of liquid amine processes. The CO2 capture capacity of solid amine sorbents reduce over the period of time due to the thermal instability and contaminant poisoning of the amine. Our current development focuses on improving the sorbent stability and mechanistic study of the interactions between the amine, CO2, and contaminants present in the flue gas. This dissertation presents a study of the use of polyethylene glycol (PEG) to enhance the stability of amine-immobilized silica. Long term stability of tetraethylenepentamine-immobilized on silica (TEPA/SiO2) and PEG-enhanced TEPA/SiO2 (PEG/TEPA/SiO2) were evaluated by performing multiple cycles of CO2 capture on the sorbents under the constant monitoring of in situ infrared and mass spectrometers. PEG/TEPA/SiO2 shows slower degradation than TEPA/SiO2. The IR absorbance spectra reveal that the accumulation of the strongly adsorbed CO2 species as bicarbonates and carboxylates is the cause of sorbent degradation. The IR absorbance spectra further suggested that the presence of PEG decreased the formation of these strongly adsorbed CO2, reducing the degradation of the sorbent. The interactions between the -NH2 groups, CO2, and other electron acceptor species present in the flue gas govern the CO2 capture capacity and long term stability of the sorbent. The flue gas from coal-fired power plants contains 40-250 ppm of SO2 and 5-7 vol% of H2O. Although the presence of these species in the flue gas is expected to influence the performance of the sorbent, the extent of the interaction between the amine groups and these species has not been studied. CO2 capture under the presence of 250 ppm in the CO2 adsorption stream was performed on TPSENa sorbent (29 wt% TEPA, 18 wt% PEG, 49 wt% SiO2, 3.8 wt% EPON, and 0.2 wt% Na2CO3). The initial CO2 capture capacity of TPSENa was 1.195 mmol-CO2/g-sorb. which decreased to 0.532 mmol-CO2/g-sorb. after 24 cycles of CO2 capture under presence of 250 ppm SO2. The CO2 capture capacity of TPSENa showed a slight reduction from 0.869 to 0.764 mmol-CO2/g-sorb. under the absence of SO2. The IR absorbance spectra indicate that formation of both strongly-adsorbed CO2 species and SO2-adsorbed species accelerated the degradation of the sorbent in the presence of SO2. The development of high stability solid amine sorbent requires an in-depth understanding of the interaction between CO2 and the amine groups. The mechanism of CO2 adsorption on amine groups follows acid-base type interaction where the CO2 acts as the acidic species and amine groups are the basic site. The products of the reaction between CO2 and the amine are ammonium ion (NH3+), carbamate, and bicarbonates. The evidence of the formation of carbamate and bicarbonates are commonly available in literatures while that of the ammonium ion is scarce. The in situ injection of HCl on TEPA/SiO2 was performed under constant infrared spectroscopic monitoring to elucidate the acid-base reaction. The IR spectra of TEPA/SiO2 after HCl injection shows similar absorption features to those of TEPA/SiO2 during CO2 adsorption, evidences for the formation of NH3+. IR spectra also suggests that HCl is likely to react with primary amine (-NH2) of TEPA and then further reacts with secondary amine (-NH), resulting in the decrease in the available amine sites for CO2 adsorption. The in situ injection of H2O on TEPA/SiO2 caused the removal of TEPA from SiO2. The results of this study have provided the several key information of which should prove to be helpful in the development of highly stable solid amine sorbent. The study of PEG-enhanced TEPA/SiO2 has shown that the stability can be improved by addition of chemical stabilizers which slows down the formation of the carboxylate species. The SO2 poisoning of the sorbent is caused by (i) accelerating the formation of strongly adsorbed CO2 species and (ii) depositing of SO2-adsorbed species on the amine sites. The further studies should focus on development of the sorbent with high resistance to HCl and SO2. Additional of aromatic amine to the alkyl amine on silica support may reduce the HCl and SO2 poisoning as the aromatic amine has a strong reactivity toward the acidic gaseous species. The addition of these compounds requires optimization to ensure that the sorbent resistance to SO2 while stability and capture capacity are not significantly affected.

Download or read book Amine pillared Nanosheet Adsorbents for CO2 Capture Applications written by Hui Jiang and published by . This book was released on 2014 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amine-functionalized solid adsorbents have gained attention within the last decade for their application in carbon dioxide capture, due to their many advantages such as low energy cost for regeneration, tunable structure, elimination of corrosion problems, and additional advantages. However, one of the challenges facing this technology is to accomplish both high CO2 capture capacity along with high CO2 diffusion rates concurrently. Current amine-based solid sorbents such as porous materials similar to SBA-15 have large pores diffusion entering molecules; however, the pores become clogged upon amine inclusion. To meet this challenge, our group's solution involves the creation of a new type of material which we are calling-amino-pillared nanosheet (APN) adsorbents which are generated from layered nanosheet precursors. These materials are being proposed because of their unique lamellar structure which exhibits ability to be modified by organic or inorganic pillars through consecutive swelling and pillaring steps to form large mesoporous interlayer spaces. After the expansion of the layer space through swelling and pillaring, the large pore space can be functionalized with amine groups. This selective functionalization is possible by the choice of amine group introduced. Our choice, large amine molecules, do not access the micropore within each layer; however, either physically or chemically immobilized onto the surface of the mesoporous interlayer space between each layer. The final goal of the research is to investigate the ability to prepare APN adsorbents from a model nanoporous layered materials including nanosheets precursor material MCM-22(P) and nanoporous layered silicate material AMH-3. MCM-22(P) contains 2-dimensional porous channels, 6 membered rings (MB) openings perpendicular to the layers and 10 MB channels in the plane of the layers.1 However, the transport limiting openings (6 MB) to the layers is smaller than CO2 gas molecules.2,3 In contrast, AMH-3 has 3D microporous layers with 8 MB openings in the plane of the layers, as well as perpendicular to the layers, which are larger than CO2 molecules. Based on the structure differences between nanosheets precursor material MCM-22(P) and nanoporous layered silicate material AMH-3, the latter might be more suitable for CO2 capturer application as an APN candidate material. However, none of the assumptions above have been approved experimentally. In this study, the influence of the amine loading on adsorption capacity and kinetics of adsorption for the mixed porosity material pillared MCM-22 (P) (also called MCM-36) is studied systematically, in order to determine a potential route to achieve a final material with both high amine loading and high adsorption capacity. We first synthesized MCM-22(P), followed by swelling and pillaring to create MCM-36. Polymeric amines such as polyethylenimine (PEI) are used as an organic component of the supported amine adsorbents, with varying polymer loadings within the adsorbents used. The kinetics and diffusion properties of carbon dioxide capture on a MCM-36 pillared material impregnated with amine containing Polyethylenimine polymers has been investigated. It was determined that the introduction of amine polymer cannot be used to improve the capture capacity of the support over that of the bare material, due to the fact that with the addition of a high loading of amine polymer the large pore diffusion channels become impossible for carbon dioxide molecules to diffuse through. This sets an upper limit to the capture capacity of polymer impregnated MCM-36 for carbon dioxide which does not surpass that for the initial bare material, and greatly reduces the utility of using this sort of amine-solid adsorbent for carbon capture plans in the future.

Download or read book Advanced CO2 Capture Technologies written by Shin-ichi Nakao and published by Springer. This book was released on 2019-05-07 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarises the advanced CO2 capture technologies that can be used to reduce greenhouse gas emissions, especially those from large-scale sources, such as power-generation and steel-making plants. Focusing on the fundamental chemistry and chemical processes, as well as advanced technologies, including absorption and adsorption, it also discusses other aspects of the major CO2 capture methods: membrane separation; the basic chemistry and process for CO2 capture; the development of materials and processes; and practical applications, based on the authors’ R&D experience. This book serves as a valuable reference resource for researchers, teachers and students interested in CO2 problems, providing essential information on how to capture CO2 from various types of gases efficiently. It is also of interest to practitioners and academics, as it discusses the performance of the latest technologies applied in large-scale emission sources.

Download or read book Synthesis of Amine modified Aerogel Sorbents and Metal organic Framework 5 MOF 5 Membranes for Carbon Dioxide Separation written by Teresa M. Rosa and published by . This book was released on 2010 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amine-modified solid sorbents and membrane separation are promising technologies for separation and capture of carbon dioxide (CO2) from combustion flue gas. Amine absorption processes are mature, but still have room for improvement. This work focused on the synthesis of amine-modified aerogels and metal-organic framework-5 (MOF-5) membranes for CO2 separation. A series of solid sorbents were synthesized by functionalizing amines on the surface of silica aerogels. This was done by three coating methods: physical adsorption, magnetically assisted impact coating (MAIC) and atomic layer deposition (ALD). CO2 adsorption capacity of the sorbents was measured at room temperature in a Cahn microbalance. The sorbents synthesized by physical adsorption show the largest CO2 adsorption capacity (1.43-1.63 mmol CO2/g). An additional sorbent synthesized by ALD on hydrophilic aerogels at atmospheric pressures shows an adsorption capacity of 1.23 mmol CO2/g. Studies on one amine-modified sorbent show that the powder is of agglomerate bubbling fluidization (ABF) type. The powder is difficult to fluidize and has limited bed expansion. The ultimate goal is to configure the amine-modified sorbents in a micro-jet assisted gas fluidized bed to conduct adsorption studies. MOF-5 membranes were synthesized on α-alumina supports by two methods: in situ synthesis and secondary growth synthesis. Characterization by scanning electron microscope (SEM) imaging and X-ray diffraction (XRD) show that the membranes prepared by both methods have a thickness of 14-16 μm, and a MOF-5 crystal size of 15-25 μm with no apparent orientation. Single gas permeation results indicate that the gas transport through both membranes is determined by a combination of Knudsen diffusion and viscous flow. The contribution of viscous flow indicates that the membranes have defects.

Download or read book In situ Spectroscopic Investigation of CO2 and SO2 Adsorption Mechanisms on Amine Sorbents written by Uma Tumuluri and published by . This book was released on 2014 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: CO2 capture using amine sorbents is a promising technology for CO2 capture from point sources because of its low energy requirement, low equipment corrosion. Thermal swing adsorption (TSA) using amine sorbents, which operates with CO2 adsorption at 40-55°C and desorption at 100-120°C, could be a cost-effective process for removal of CO2 from coal-fired power plants becasue of the availability of steam for sorbent regeneration. In situ FTIR spectroscopy was used to study the interaction of CO2 with amine sorbents. Adsorbed CO2 on amine sorbents exists in the form of carbamate-ammonium ion pairs, carbamate-ammonium zwitterions and carbamic acid. Carbamate and carbamic acid on sorbents with low amine density desorbed at a faster rate than those on sorbents with high amine density after switching the flow from CO2 to Ar at 55°C. Evaluation of the desorption temperature profiles showed that the temperature required to achieve maximum desorption of CO2 (Tmax. des) increases with the amine density. Flue gas emitted from coal fired power plants after selective catalytic reduction and flue gas desulfurization units contains approximately 3-4% O2, 12-15% CO2, 5-10% H2O, 50-200 ppm SO2, 100-400 ppm NOx. The long term stability of the amine sorbents in flue gas conditions is one of the key operational aspects that the determine the economic viability of the CO2 capture using amine sorbents. The performance of the amine sorbents in the simulated flue gas conditions was evaluated using in situ FTIR spectroscopy. FTIR results revealed that sulfates/sulfites that are formed in presence of SO2 and SO2/H2O bind strongly with amine sites. Evaluation of the break through curves revealed that the competitive adsorption of SO2 and CO2 on the amine sites occurs at low CO2 concentration. The adsorption of CO2 dominates the SO2 at high CO2 concentration. In situ FTIR SO2 capture studies on amine sorbents revealed that SO2 adsorbs in form of ammonium ions and sulfates on the amine sorbents. Analysis of the IR spectra of the adsorbed SO2 revealed that the sorbents containing primary and secondary amine adsorb SO2 irreversibly and tertiary amine sorbents adsorbed SO2 reversibly. The results of these fundamental studies help in designing a suitable sorbent for CO2 capture process, which has high CO2 capture capacity and high SO2 tolerance.

Download or read book Effects of O sub 2 and SO sub 2 on the Capture Capacity of a Primary Amine Based Polymeric CO sub 2 Sorbent written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Post combustion CO2 capture is most commonly carried out using an amine solution that results in a high parasitic energy cost in the stripper unit due to the need to heat the water which comprises a majority of the amine solution. It is also well known that amine solvents suffer from stability issues due to amine leaching and poisoning by flue gas impurities. Solid sorbents provide an alternative to solvent systems that would potentially reduce the energy penalty of carbon capture. However, the cost of using a particular sorbent is greatly affected by the usable lifetime of the sorbent. This work investigated the stability of a primary amine-functionalized ion exchange resin in the presence of O2 and SO2, both of which are constituents of flue gas that have been shown to cause degradation of various amines in solvent processes. The CO2 capture capacity was measured over multiple capture cycles under continuous exposure to two simulated flue gas streams, one containing 12 vol% CO2, 4% O2, 84% N2, and the other containing 12.5 vol% CO2, 4% O2, 431 ppm SO2, balance N2 using a custom-built packed bed reactor. The resin maintained its CO2 capture capacity of 1.31 mol/kg over 17 capture cycles in the presence of O2 without SO2. However, the CO2 capture capacity of the resin decreased rapidly under exposure to SO2 by an amount of 1.3 mol/kg over 9 capture cycles. Elemental analysis revealed the resin adsorbed 1.0 mol/kg of SO2. Thermal regeneration was determined to not be possible. The poisoned resin was, however, partially regenerated with exposure to 1.5M NaOH for 3 days resulting in a 43% removal of sulfur, determined through elemental analysis, and a 35% recovery of CO2 capture capacity. Evidence was also found for amine loss upon prolonged (7 days) continuous exposure to high temperatures (120 C) in air. It is concluded that desulfurization of the flue gas stream prior to CO2 capture will greatly improve the economic viability of using this solid sorbent in a post-combustion CO2 capture process.

Download or read book Adsorption on New and Modified Inorganic Sorbents written by A. Dabrowski and published by Elsevier. This book was released on 1996-01-15 with total page 945 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been a lack of authoritative, current information on the structure, investigation and preparation of inorganic sorbents, their numerous applications as well as the adsorption from gaseous and liquid phases on new and chemically modified inorganic solids. This volume deals with the above-mentioned themes and presents 34 up-to-date comprehensive and critical reviews written by well-recognized authorities. The sorbents discussed are primarily mineral ones. Each contribution treats a problem critically by showing its development, presenting documentation on the state-of-the-art and identifying subjects for further research. The book will be of interest to researchers in academic institutes and industrial laboratories engaged in the fields of surface chemistry, inorganic chemistry, adsorption, ion-exchange, catalysis, chromatography and spectroscopy of the surface phenomena, as well as to students attending graduate and postgraduate courses.

Download or read book Spectroscopic Evaluation of the CO2 Adsorption Properties on Amine Functionalized Polyvinyl Alcohol and Silica Sorbents written by Yuxin Zhai and published by . This book was released on 2014 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: Porous polyvinyl alcohol (PVA) and silica particles with amine surface functional groups have been prepared for the efficient CO2 capture power plants. The porous PVA membranes or particles were obtained by phase inversion in non-solvent, using glutaraldehyde (GA) as a crosslinking agent. An insoluble amine-PVA or amine-silica network was prepared by immobilizing polyethyleneimine (PEI) on the PVA or silica surface. The performance of the amine functionalized PVA and silica sorbents were tested by CO2 adsorption, and the effect of operational parameters were determined by in-situ IR spectroscopy. The adsorption isotherms for the CO2 adsorbed species formed on amine functionalized silica sorbents were generated at different temperatures. The CO2 adsorbed species were identified by IR spectroscopy and their formation was evaluated at the typical temperature and concentration of CO2 in the flue gas of natural gas-fired power plants. Multiple data points were generated in the low partial pressure region of the isotherms to assess the equilibrium and specify the technical requirements for the sorbents to serve in CO2 capture processes for natural gas-fired power plants.

Download or read book Development of New Carbon Dioxide Sorbents written by Bryce Dutcher and published by . This book was released on 2015 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.