Techno-Economic Assessment of Four CO2 Storage Sites

Directory of Open Access Journals (Sweden)

Gruson J.-F.

2015-04-01

Full Text Available Carbon Capture and Storage (CCS should be a key technology in order to achieve a decline in the CO2 emissions intensity of the power sector and other intensive industry, but this potential deployment could be restricted by cost issues as the International Energy Agency (IEA in their last projections (World Energy Outlook 2013 has considered only around 1% of global fossil fuel-fired power plants could be equipped with CCS by 2035. The SiteChar project funded by 7th Framework Programme of European Commission gives the opportunity to evaluate the most influential parameters of techno-economic evaluations of four feasible European projects for CO2 geological storage located onshore and offshore and related to aquifer storage or oil and gas reservoirs, at different stages of characterization. Four potential CO2 storage sites have been assessed in terms of storage costs per tonne of CO2 permanently stored (equivalent cost based. They are located offshore UK, onshore Denmark, offshore Norway and offshore Italy. The four SiteChar techno-economic evaluations confirm it is not possible to derive any meaningful average cost for a CO2 storage site. The results demonstrate that the structure of costs for a project is heterogeneous and the storage cost is consequently site dependent. The strategy of the site development is fundamental, the technical choices such as the timing, rate and duration of injection are also important. The way monitoring is managed, using observation wells and logging has a strong impact on the estimated monitoring costs. Options to lower monitoring costs, such as permanent surveys, exist and should be further investigated. Table 1 below summarizes the cost range in Euro per tonne (Discount Rate (DR at 8% for the different sites, which illustrates the various orders of magnitude due to the specificities of each site. These figures have how to be considered with care. In particular the Italian and Norwegian sites present very specific

Triazine containing N-rich microporous organic polymers for CO2 capture and unprecedented CO2/N2 selectivity

International Nuclear Information System (INIS)

Bhunia, Subhajit; Bhanja, Piyali; Das, Sabuj Kanti; Sen, Tapas; Bhaumik, Asim

2017-01-01

Targeted synthesis of microporous adsorbents for CO 2 capture and storage is very challenging in the context of remediation from green house gases. Herein we report two novel N-rich microporous networks SB-TRZ-CRZ and SB-TRZ-TPA by extensive incorporation of triazine containing tripodal moiety in the porous polymer framework. These materials showed excellent CO 2 storage capacities: SB-TRZ-CRZ displayed the CO 2 uptake capacity of 25.5 wt% upto 1 bar at 273 K and SB-TRZ-TPA gave that of 16 wt% under identical conditions. The substantial dipole quadruple interaction between network (polar triazine) and CO 2 boosts the selectivity for CO 2 /N 2 . SB-TRZ-CRZ has this CO 2 /N 2 selectivity ratio of 377, whereas for SB-TRZ-TPA it was 97. Compared to other porous polymers, these materials are very cost effective, scalable and very promising material for clean energy application and environmental issues. - Graphical abstract: We report two novel N-rich microporous polymeric materials by doping of triazine containing tripodal dopant in the organic framework. These materials showed excellent CO 2 storage capacities as high as 25.5 wt% under 1 bar pressure with exceptional CO 2 /N 2 selectivity of 377. - Highlights: • Triazine containing trimodal moiety incorporated in polycarbazolic and poly triphenylamine networks. • N-rich crosslinked polymers with high BET surface area and 1.5–1.7 nm size large micropores. • CO 2 uptake capacity of 25.5 wt% upto 1 bar at 273 K. • These crosslinked porous polymers showed exceptional CO 2 /N 2 selectivity.

Mesostructure-Induced Selectivity in CO2 Reduction Catalysis.

Science.gov (United States)

Hall, Anthony Shoji; Yoon, Youngmin; Wuttig, Anna; Surendranath, Yogesh

2015-12-02

Gold inverse opal (Au-IO) thin films are active for CO2 reduction to CO with high efficiency at modest overpotentials and high selectivity relative to hydrogen evolution. The specific activity for hydrogen evolution diminishes by 10-fold with increasing porous film thickness, while CO evolution activity is largely unchanged. We demonstrate that the origin of hydrogen suppression in Au-IO films stems from the generation of diffusional gradients within the pores of the mesostructured electrode rather than changes in surface faceting or Au grain size. For electrodes with optimal mesoporosity, 99% selectivity for CO evolution can be obtained at overpotentials as low as 0.4 V. These results establish electrode mesostructuring as a complementary method for tuning selectivity in CO2-to-fuels catalysis.

CO2 Storage Feasibility: A Workflow for Site Characterisation

Directory of Open Access Journals (Sweden)

Nepveu Manuel

2015-04-01

Full Text Available In this paper, we present an overview of the SiteChar workflow model for site characterisation and assessment for CO2 storage. Site characterisation and assessment is required when permits are requested from the legal authorities in the process of starting a CO2 storage process at a given site. The goal is to assess whether a proposed CO2 storage site can indeed be used for permanent storage while meeting the safety requirements demanded by the European Commission (EC Storage Directive (9, Storage Directive 2009/31/EC. Many issues have to be scrutinised, and the workflow presented here is put forward to help efficiently organise this complex task. Three issues are highlighted: communication within the working team and with the authorities; interdependencies in the workflow and feedback loops; and the risk-based character of the workflow. A general overview (helicopter view of the workflow is given; the issues involved in communication and the risk assessment process are described in more detail. The workflow as described has been tested within the SiteChar project on five potential storage sites throughout Europe. This resulted in a list of key aspects of site characterisation which can help prepare and focus new site characterisation studies.

Promoting Ethylene Selectivity from CO2 Electroreduction on CuO Supported onto CO2 Capture Materials.

Science.gov (United States)

Yang, Hui-Juan; Yang, Hong; Hong, Yu-Hao; Zhang, Peng-Yang; Wang, Tao; Chen, Li-Na; Zhang, Feng-Yang; Wu, Qi-Hui; Tian, Na; Zhou, Zhi-You; Sun, Shi-Gang

2018-03-09

Cu is a unique catalyst for CO 2 electroreduction, since it can catalyze CO 2 reduction to a series of hydrocarbons, alcohols, and carboxylic acids. Nevertheless, such Cu catalysts suffer from poor selectivity. High pressure of CO 2 is considered to facilitate the activity and selectivity of CO 2 reduction. Herein, a new strategy is presented for CO 2 reduction with improved C 2 H 4 selectivity on a Cu catalyst by using CO 2 capture materials as the support at ambient pressure. N-doped carbon (N x C) was synthesized through high-temperature carbonization of melamine and l-lysine. We observed that the CO 2 uptake capacity of N x C depends on both the microporous area and the content of pyridinic N species, which can be controlled by the carbonization temperature (600-800 °C). The as-prepared CuO/N x C catalysts exhibit a considerably higher C 2 H 4 faradaic efficiency (36 %) than CuO supported on XC-72 carbon black (19 %), or unsupported CuO (20 %). Moreover, there is a good linear relationship between the C 2 H 4 faradaic efficiency and CO 2 uptake capacity of the supports for CuO. The local high CO 2 concentration near Cu catalysts, created by CO 2 capture materials, was proposed to increase the coverage of CO intermediate, which is favorable for the coupling of two CO units in the formation of C 2 H 4 . This study demonstrates that pairing Cu catalysts with CO 2 capture supports is a promising approach for designing highly effective CO 2 reduction electrocatalysts. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tuning of CO2 Reduction Selectivity on Metal Electrocatalysts.

Science.gov (United States)

Wang, Yuhang; Liu, Junlang; Wang, Yifei; Al-Enizi, Abdullah M; Zheng, Gengfeng

2017-11-01

Climate change, caused by heavy CO 2 emissions, is driving new demands to alleviate the rising concentration of atmospheric CO 2 levels. Enlightened by the photosynthesis of green plants, photo(electro)chemical catalysis of CO 2 reduction, also known as artificial photosynthesis, is emerged as a promising candidate to address these demands and is widely investigated during the past decade. Among various artificial photosynthetic systems, solar-driven electrochemical CO 2 reduction is widely recognized to possess high efficiencies and potentials for practical application. The efficient and selective electroreduction of CO 2 is the key to the overall solar-to-chemical efficiency of artificial photosynthesis. Recent studies show that various metallic materials possess the capability to play as electrocatalysts for CO 2 reduction. In order to achieve high selectivity for CO 2 reduction products, various efforts are made including studies on electrolytes, crystal facets, oxide-derived catalysts, electronic and geometric structures, nanostructures, and mesoscale phenomena. In this Review, these methods for tuning the selectivity of CO 2 electrochemical reduction of metallic catalysts are summarized. The challenges and perspectives in this field are also discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Geochemical Influence on Microbial Communities at CO2-Leakage Analog Sites.

Science.gov (United States)

Ham, Baknoon; Choi, Byoung-Young; Chae, Gi-Tak; Kirk, Matthew F; Kwon, Man Jae

2017-01-01

Microorganisms influence the chemical and physical properties of subsurface environments and thus represent an important control on the fate and environmental impact of CO 2 that leaks into aquifers from deep storage reservoirs. How leakage will influence microbial populations over long time scales is largely unknown. This study uses natural analog sites to investigate the long-term impact of CO 2 leakage from underground storage sites on subsurface biogeochemistry. We considered two sites with elevated CO 2 levels (sample groups I and II) and one control site with low CO 2 content (group III). Samples from sites with elevated CO 2 had pH ranging from 6.2 to 4.5 and samples from the low-CO 2 control group had pH ranging from 7.3 to 6.2. Solute concentrations were relatively low for samples from the control group and group I but high for samples from group II, reflecting varying degrees of water-rock interaction. Microbial communities were analyzed through clone library and MiSeq sequencing. Each 16S rRNA analysis identified various bacteria, methane-producing archaea, and ammonia-oxidizing archaea. Both bacterial and archaeal diversities were low in groundwater with high CO 2 content and community compositions between the groups were also clearly different. In group II samples, sequences classified in groups capable of methanogenesis, metal reduction, and nitrate reduction had higher relative abundance in samples with relative high methane, iron, and manganese concentrations and low nitrate levels. Sequences close to Comamonadaceae were abundant in group I, while the taxa related to methanogens, Nitrospirae , and Anaerolineaceae were predominant in group II. Our findings provide insight into subsurface biogeochemical reactions that influence the carbon budget of the system including carbon fixation, carbon trapping, and CO 2 conversion to methane. The results also suggest that monitoring groundwater microbial community can be a potential tool for tracking CO 2

Geochemical Influence on Microbial Communities at CO2-Leakage Analog Sites

Directory of Open Access Journals (Sweden)

Baknoon Ham

2017-11-01

Full Text Available Microorganisms influence the chemical and physical properties of subsurface environments and thus represent an important control on the fate and environmental impact of CO2 that leaks into aquifers from deep storage reservoirs. How leakage will influence microbial populations over long time scales is largely unknown. This study uses natural analog sites to investigate the long-term impact of CO2 leakage from underground storage sites on subsurface biogeochemistry. We considered two sites with elevated CO2 levels (sample groups I and II and one control site with low CO2 content (group III. Samples from sites with elevated CO2 had pH ranging from 6.2 to 4.5 and samples from the low-CO2 control group had pH ranging from 7.3 to 6.2. Solute concentrations were relatively low for samples from the control group and group I but high for samples from group II, reflecting varying degrees of water-rock interaction. Microbial communities were analyzed through clone library and MiSeq sequencing. Each 16S rRNA analysis identified various bacteria, methane-producing archaea, and ammonia-oxidizing archaea. Both bacterial and archaeal diversities were low in groundwater with high CO2 content and community compositions between the groups were also clearly different. In group II samples, sequences classified in groups capable of methanogenesis, metal reduction, and nitrate reduction had higher relative abundance in samples with relative high methane, iron, and manganese concentrations and low nitrate levels. Sequences close to Comamonadaceae were abundant in group I, while the taxa related to methanogens, Nitrospirae, and Anaerolineaceae were predominant in group II. Our findings provide insight into subsurface biogeochemical reactions that influence the carbon budget of the system including carbon fixation, carbon trapping, and CO2 conversion to methane. The results also suggest that monitoring groundwater microbial community can be a potential tool for tracking

Detection of CO2 leaks from carbon capture and storage sites with combined atmospheric CO2 and O-2 measurements

NARCIS (Netherlands)

van Leeuwen, Charlotte; Meijer, Harro A. J.

2015-01-01

This paper presents a transportable instrument that simultaneously measures the CO2 and (relative) O-2 concentration of the atmosphere with the purpose to aid in the detection of CO2 leaks from CCS sites. CO2 and O-2 are coupled in most processes on earth (e.g., photosynthesis, respiration and

Fischer-Tropsch Synthesis: Influence of CO Conversion on Selectivities H2/CO Usage Ratios and Catalyst Stability for a 0.27 percent Ru 25 percent Co/Al2O3 using a Slurry Phase Reactor

Energy Technology Data Exchange (ETDEWEB)

W Ma; G Jacobs; Y Ji; T Bhatelia; D Bukur; S Khalid; B Davis

2011-12-31

The effect of CO conversion on hydrocarbon selectivities (i.e., CH{sub 4}, C{sub 5+}, olefin and paraffin), H{sub 2}/CO usage ratios, CO{sub 2} selectivity, and catalyst stability over a wide range of CO conversion (12-94%) on 0.27%Ru-25%Co/Al{sub 2}O{sub 3} catalyst was studied under the conditions of 220 C, 1.5 MPa, H{sub 2}/CO feed ratio of 2.1 and gas space velocities of 0.3-15 NL/g-cat/h in a 1-L continuously stirred tank reactor (CSTR). Catalyst samples were withdrawn from the CSTR at different CO conversion levels, and Co phases (Co, CoO) in the slurry samples were characterized by XANES, and in the case of the fresh catalysts, EXAFS as well. Ru was responsible for increasing the extent of Co reduction, thus boosting the active site density. At 1%Ru loading, EXAFS indicates that coordination of Ru at the atomic level was virtually solely with Co. It was found that the selectivities to CH{sub 4}, C{sub 5+}, and CO{sub 2} on the Co catalyst are functions of CO conversion. At high CO conversions, i.e. above 80%, CH{sub 4} selectivity experienced a change in the trend, and began to increase, and CO{sub 2} selectivity experienced a rapid increase. H{sub 2}/CO usage ratio and olefin content were found to decrease with increasing CO conversion in the range of 12-94%. The observed results are consistent with water reoxidation of Co during FTS at high conversion. XANES spectroscopy of used catalyst samples displayed spectra consistent with the presence of more CoO at higher CO conversion levels.

Photocatalytic reduction of CO2 to CO over copper decorated g-C3N4 nanosheets with enhanced yield and selectivity

Science.gov (United States)

Shi, Guodong; Yang, Lin; Liu, Zhuowen; Chen, Xiao; Zhou, Jianqing; Yu, Ying

2018-01-01

Photocatalytic reduction of CO2 to fuel has attracted considerable attention due to the consumption of fossil fuels and serious environmental problems. Although there are many photocatalysts reported for CO2 reduction, the improvement of activity and selectivity is still in great need of. In this work, a series of Cu nanoparticle decorated g-C3N4 nanosheets with different Cu loadings were fabricated by a facile secondary calcination and subsequent microwave hydrothermal method. The designed catalysts shown good photocatalytic activity and selectivity for CO2 reduction to CO. The optimal sample exhibited a 3-fold augmentation of the CO yield in comparison with pristine g-C3N4 under visible light. It is revealed that with the loading of Cu nanoparticles, the resulting photocatalyst possessed an improved charge carrier transfer and separation efficiency as well as increased surface reactive sites, resulting in a significant enhancement of CO yield. It is anticipated that the designed Cu/C3N4 photocatalyst may provide new insights for two dimensional layer materials and non-noble particles applied to CO2 reduction.

Satellite assisted aerosol correlation in a sequestered CO2 leakage controlled site

Science.gov (United States)

Landulfo, Eduardo; da Silva Lopes, Fábio J.; Nakaema, Walter M.; de Medeiros, José A. G.; Moreira, Andrea

2014-10-01

Currently one of the main challenges in CO2 storage research is to grant the development, testing and validation of accurate and efficient Measuring, Monitoring and Verification (MMV) techniques to be deployed at the final storage site, targeting maximum storage efficiency at the minimal leakage risk levels. For such task a mimetic sequestration site has been deployed in Florianopolis, Brazil, in order to verify the performance of monitoring plataforms to detect and quantify leakages of ground injected CO2, namely a Cavity Ring Down System (CRDS) - Los Gatos Research - an Eddy Covariance System (Campbell Scientific and Irgason) and meteorological tower for wind, humidity, precipitation and temperature monitoring onsite. The measurement strategy for detecting CO2 leakages can be very challenging since environmental and phytogenic influence can be very severe and play a role on determining if the values measured are unambiguous or not. One external factor to be considered is the amount of incoming solar radiation which will be the driving force for the whole experimental setup and following this reasoning the amount of aerosols in the atmospheric column can be a determinant factor influencing the experimental results. Thus the investigation of measured fluxes CO2 and its concentration with the aforementioned experimental instruments and their correlation with the aerosol data should be taken into account by means of satellite borne systems dedicated to measure aerosol vertical distribution and its optical properties, in this study we have selected CALIPSO and MODIS instrumentation to help on deriving the aerosol properties and CO2 measurements.

Polyacrylonitrile-Derived Sponge-Like Micro/Macroporous Carbon for Selective CO2 Separation.

Science.gov (United States)

Guo, Li-Ping; Hu, Qing-Tao; Zhang, Peng; Li, Wen-Cui; Lu, An-Hui

2018-03-25

CO 2 capture under a dynamical flow situation requires adsorbents possessing balanced proportion of macropores as diffusion path and micropores as adsorption reservoir. However, the construction of interconnected micro-/macropores structure coupled with abundant nitrogen species into one carbon skeleton remains a challenge. Here, we report a new approach to prepare sponge-like carbon with a well-developed micro-/macroporous structure and enriched nitrogen species through aqueous phase polymerization of acrylonitrile in the presence of graphene oxide. The tension stress caused by the uniform thermal shrinkage of polyacrylonitrile during the pyrolysis together with the favorable flexibility of graphene oxide sheets are responsible for the formation of the sponge-like morphology. The synergistic effect of micro-/macroporous framework and rich CO 2 -philic site enables such carbon to decrease resistance to mass transfer and show high CO 2 dynamic selectivity over N 2 (454) and CH 4 (11), as well as good CO 2 capacity at 298 K under low CO 2 partial pressure (0.17 bar, a typical CO 2 partial pressure in flue gas). The above attributes make this porous carbon a promising candidate for CO 2 capture from flue gas, methane sources and other relevant applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

CO2 Accounting and Risk Analysis for CO2 Sequestration at Enhanced Oil Recovery Sites.

Science.gov (United States)

Dai, Zhenxue; Viswanathan, Hari; Middleton, Richard; Pan, Feng; Ampomah, William; Yang, Changbing; Jia, Wei; Xiao, Ting; Lee, Si-Yong; McPherson, Brian; Balch, Robert; Grigg, Reid; White, Mark

2016-07-19

Using CO2 in enhanced oil recovery (CO2-EOR) is a promising technology for emissions management because CO2-EOR can dramatically reduce sequestration costs in the absence of emissions policies that include incentives for carbon capture and storage. This study develops a multiscale statistical framework to perform CO2 accounting and risk analysis in an EOR environment at the Farnsworth Unit (FWU), Texas. A set of geostatistical-based Monte Carlo simulations of CO2-oil/gas-water flow and transport in the Morrow formation are conducted for global sensitivity and statistical analysis of the major risk metrics: CO2/water injection/production rates, cumulative net CO2 storage, cumulative oil/gas productions, and CO2 breakthrough time. The median and confidence intervals are estimated for quantifying uncertainty ranges of the risk metrics. A response-surface-based economic model has been derived to calculate the CO2-EOR profitability for the FWU site with a current oil price, which suggests that approximately 31% of the 1000 realizations can be profitable. If government carbon-tax credits are available, or the oil price goes up or CO2 capture and operating expenses reduce, more realizations would be profitable. The results from this study provide valuable insights for understanding CO2 storage potential and the corresponding environmental and economic risks of commercial-scale CO2-sequestration in depleted reservoirs.

Selective CO Methanation on Highly Active Ru/TiO2 Catalysts: Identifying the Physical Origin of the Observed Activation/Deactivation and Loss in Selectivity

DEFF Research Database (Denmark)

Abdel-Mageed, Ali M.; Widmann, Daniel; Olesen, Sine Ellemann

2018-01-01

Ru /TiO2 catalysts are highly active and selective in the selective methanation of CO in the presence of large amounts of CO2, but suffer from a considerable deactivation and loss of selectivity during time on stream. Aiming at a fundamental understanding of these processes, we have systematically...... different effects such as structural effects, adlayer effects such as site blocking effects and changes in the chemical (surface) composition of the catalysts. Operando XANES / EXAFS measurements revealed that an initial activation phase is largely due to the reduction of oxidized Ru species, together...

Controlling selectivities in CO2 reduction through mechanistic understanding

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiang; Shi, Hui; Szanyi, János

2017-09-11

Catalytic CO2 conversion to energy carriers and intermediates is of utmost importance to energy and environmental goals. However, the lack of fundamental understanding of the reaction mechanism renders designing a selective catalyst inefficient. We performed operando FTIR/SSITKA experiments to understand the correlation between the kinetics of product formation and that of surface species conversion during CO2 reduction over Pd/Al2O3 catalysts. We found that the rate-determining step for CO formation is the conversion of adsorbed formate, while that for CH4 formation is the hydrogenation of adsorbed carbonyl. The balance of the hydrogenation kinetics between adsorbed formates and carbonyls governs the selectivities to CH4 and CO. We demonstrated how this knowledge can be used to design catalysts to achieve high selectivities to desired products.

Regulation of Coordination Number over Single Co Sites: Triggering the Efficient Electroreduction of CO2.

Science.gov (United States)

Wang, Xiaoqian; Chen, Zhao; Zhao, Xuyan; Yao, Tao; Chen, Wenxing; You, Rui; Zhao, Changming; Wu, Geng; Wang, Jing; Huang, Weixin; Yang, Jinlong; Hong, Xun; Wei, Shiqiang; Wu, Yuen; Li, Yadong

2018-02-12

The design of active, selective, and stable CO 2 reduction electrocatalysts is still challenging. A series of atomically dispersed Co catalysts with different nitrogen coordination numbers were prepared and their CO 2 electroreduction catalytic performance was explored. The best catalyst, atomically dispersed Co with two-coordinate nitrogen atoms, achieves both high selectivity and superior activity with 94 % CO formation Faradaic efficiency and a current density of 18.1 mA cm -2 at an overpotential of 520 mV. The CO formation turnover frequency reaches a record value of 18 200 h -1 , surpassing most reported metal-based catalysts under comparable conditions. Our experimental and theoretical results demonstrate that lower a coordination number facilitates activation of CO 2 to the CO 2 .- intermediate and hence enhances CO 2 electroreduction activity. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cp*Co(III) Catalyzed Site-Selective C-H Activation of Unsymmetrical O-Acyl Oximes: Synthesis of Multisubstituted Isoquinolines from Terminal and Internal Alkynes.

Science.gov (United States)

Sun, Bo; Yoshino, Tatsuhiko; Kanai, Motomu; Matsunaga, Shigeki

2015-10-26

The synthesis of isoquinolines by site-selective C-H activation of O-acyl oximes with a Cp*Co(III) catalyst is described. In the presence of this catalyst, the C-H activation of various unsymmetrically substituted O-acyl oximes selectively occurred at the sterically less hindered site, and reactions with terminal as well as internal alkynes afforded the corresponding products in up to 98 % yield. Whereas the reactions catalyzed by the Cp*Co(III) system proceeded with high site selectivity (15:1 to 20:1), use of the corresponding Cp*Rh(III) catalysts led to low selectivities and/or yields when unsymmetrical O-acyl oximes and terminal alkynes were used. Deuterium labeling studies indicate a clear difference in the site selectivity of the C-H activation step under Cp*Co(III) and Cp*Rh(III) catalysis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microporous carbonaceous adsorbents for CO2 separation via selective adsorption

KAUST Repository

Zhao, Yunfeng; Liu, Xin; Han, Yu

2015-01-01

Selective adsorption of CO2 has important implications for many energy and environment-related processes, which require the separation of CO2 from other gases (e.g. N2 and CH4) with high uptakes and selectivity. The development of high

Triazine containing N-rich microporous organic polymers for CO{sub 2} capture and unprecedented CO{sub 2}/N{sub 2} selectivity

Energy Technology Data Exchange (ETDEWEB)

Bhunia, Subhajit; Bhanja, Piyali; Das, Sabuj Kanti [Department of Material Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Sen, Tapas [Nanobiomaterials Research Group, Centre for Materials Science, School of Physical Sciences and Computing, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Bhaumik, Asim, E-mail: msab@iacs.res.in [Department of Material Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

2017-03-15

Targeted synthesis of microporous adsorbents for CO{sub 2} capture and storage is very challenging in the context of remediation from green house gases. Herein we report two novel N-rich microporous networks SB-TRZ-CRZ and SB-TRZ-TPA by extensive incorporation of triazine containing tripodal moiety in the porous polymer framework. These materials showed excellent CO{sub 2} storage capacities: SB-TRZ-CRZ displayed the CO{sub 2} uptake capacity of 25.5 wt% upto 1 bar at 273 K and SB-TRZ-TPA gave that of 16 wt% under identical conditions. The substantial dipole quadruple interaction between network (polar triazine) and CO{sub 2} boosts the selectivity for CO{sub 2}/N{sub 2}. SB-TRZ-CRZ has this CO{sub 2}/N{sub 2} selectivity ratio of 377, whereas for SB-TRZ-TPA it was 97. Compared to other porous polymers, these materials are very cost effective, scalable and very promising material for clean energy application and environmental issues. - Graphical abstract: We report two novel N-rich microporous polymeric materials by doping of triazine containing tripodal dopant in the organic framework. These materials showed excellent CO{sub 2} storage capacities as high as 25.5 wt% under 1 bar pressure with exceptional CO{sub 2}/N{sub 2} selectivity of 377. - Highlights: • Triazine containing trimodal moiety incorporated in polycarbazolic and poly triphenylamine networks. • N-rich crosslinked polymers with high BET surface area and 1.5–1.7 nm size large micropores. • CO{sub 2} uptake capacity of 25.5 wt% upto 1 bar at 273 K. • These crosslinked porous polymers showed exceptional CO{sub 2}/N{sub 2} selectivity.

Adsorption and separation of CO{sub 2} on Fe(II)-MOF-74: Effect of the open metal coordination site

Energy Technology Data Exchange (ETDEWEB)

Lou, Wolong; Yang, Jiangfeng; Li, Libo; Li, Jinping, E-mail: Jpli211@hotmail.com

2014-05-01

We describe the successful synthesis of Fe{sub 2}(dobdc) (dobdc{sup 4−}=2, 5-dioxido-1, 4-benzenedicarboxylate), which has an open metal coordination site Fe(II), and investigate the adsorption properties of three important molecules CO{sub 2}, CH{sub 4} and N{sub 2} on Fe{sub 2}(dobdc) and an oxidized analog, Fe{sub 2}(O{sub 2})(dobdc). We found that CO{sub 2} adsorption isotherm of Fe{sub 2}(dobdc) at 10 bar was very different from Fe{sub 2}(O{sub 2})(dobdc), with the capacities of 144.5 cm{sup 3} g{sup −1} and 98.1 cm{sup 3} g{sup −1}, respectively. The adsorption capacities for CH{sub 4} were 75.8 cm{sup 3} g{sup −1} and 36.8 cm{sup 3} g{sup −1}, respectively, at 10 bar in these materials. Using ideal adsorbed solution theory (IAST), we obtain the adsorption selectivity for CO{sub 2} using equimolar mixtures of CO{sub 2}/CH{sub 4} and CO{sub 2}/N{sub 2} with Fe{sub 2}(dobdc) and Fe{sub 2}(O{sub 2})(dobdc) as a function of pressure. Fe{sub 2}(dobdc) has a higher, more stable separation factor. - Graphical abstract: The selectivity of CO{sub 2}/CH{sub 4} mixture (50%/50%) on Fe{sub 2}(dobdc) and Fe{sub 2}(O{sub 2})(dobdc). - Highlights: • We explored the contrastive adsorption of CO{sub 2}, CH{sub 4}, and N{sub 2} in Fe{sub 2}(dobdc) and Fe{sub 2}(O{sub 2})(dobdc) for the first time. • Through IAST, we obtain the adsorption selectivity for CO{sub 2} from the equimolar mixture of CO{sub 2}/CH{sub 4} and CO{sub 2}/N{sub 2} for Fe{sub 2}(dobdc) and Fe{sub 2}(O{sub 2})(dobdc). • We determined that the open coordination site of Fe(II) is the main reason for different adsorption performances.

CO2-selective PEO–PBT (PolyActive™)/graphene oxide composite membranes

KAUST Repository

Karunakaran, Madhavan; Shevate, Rahul; Kumar, Mahendra; Peinemann, Klaus-Viktor

2015-01-01

CO2-selective graphene oxide (GO) nano-composite membranes were prepared for the first time by embedding GO into a commercially available poly(ethylene oxide)–poly(butylene terephthalate) (PEO–PBT) copolymer (PolyActive™). The as-prepared GO membrane shows high CO2 permeability (143 Barrer) and CO2/N2 selectivity (α = 73).

CO2-selective PEO–PBT (PolyActive™)/graphene oxide composite membranes

KAUST Repository

Karunakaran, Madhavan

2015-07-31

CO2-selective graphene oxide (GO) nano-composite membranes were prepared for the first time by embedding GO into a commercially available poly(ethylene oxide)–poly(butylene terephthalate) (PEO–PBT) copolymer (PolyActive™). The as-prepared GO membrane shows high CO2 permeability (143 Barrer) and CO2/N2 selectivity (α = 73).

Microporous carbonaceous adsorbents for CO2 separation via selective adsorption

KAUST Repository

Zhao, Yunfeng

2015-01-01

Selective adsorption of CO2 has important implications for many energy and environment-related processes, which require the separation of CO2 from other gases (e.g. N2 and CH4) with high uptakes and selectivity. The development of high-performance adsorbents is one of the most promising solutions to the success of these processes. The present review is focused on the state-of-the-art of carbon-based (carbonaceous) adsorbents, covering microporous inorganic carbons and microporous organic polymers, with emphasis on the correlation between their textural and compositional properties and their CO2 adsorption/separation performance. Special attention is given to the most recently developed materials that were not covered in previous reviews. We summarize various effective strategies (N-doping, surface functionalization, extra-framework ions, molecular design, and pore size engineering) for enhancing the CO2 adsorption capacity and selectivity of carbonaceous adsorbents. Our discussion focuses on CO2/N2 separation and CO2/CH4 separation, while including an introduction to the methods and criteria used for evaluating the performance of the adsorbents. Critical issues and challenges regarding the development of high-performance adsorbents as well as some overlooked facts and misconceptions are also discussed, with the aim of providing important insights into the design of novel carbonaceous porous materials for various selective adsorption based applications. This journal is © The Royal Society of Chemistry.

Comparing CO2 Storage and Advection Conditions at Night at Different Carboeuroflux Sites

Science.gov (United States)

Aubinet, M.; Berbigier, P.; Bernhofer, Ch.; et al.

Anemometer and CO2 concentration data from temporary campaigns performed at six CARBOEUROFLUX forest sites were used to estimate the importance of non-turbulent fluxes in nighttime conditions. While storage was observed to be significant only during periods of both low turbulence and low advection, the advective fluxes strongly influence the nocturnal CO2 balance, with the exception of almost flat and highly homogeneous sites. On the basis of the main factors determining the onset of advective fluxes, the ‘advection velocity’, which takes net radiation and local topography into account, was introduced as a criterion to characterise the conditions of storage enrichment/depletion. Comparative analyses of the six sites showed several common features of the advective fluxes but also some substantial differences. In particular, all sites where advection occurs show the onset of a boundary layer characterised by a downslope flow, negative vertical velocities and negative vertical CO2 concentration gradients during nighttime. As a consequence, vertical advection was observed to be positive at all sites, which corresponds to a removal of CO2 from the ecosystem. The main differences between sites are the distance from the ridge, which influences the boundary-layer depth, and the sign of the mean horizontal CO2 concentration gradients, which is probably determined by the source/sink distribution. As a consequence, both positive and negative horizontal advective fluxes (corresponding respectively to CO2 removal from the ecosystem and to CO2 supply to the ecosystem) were observed. Conclusive results on the importance of non-turbulent components in the mass balance require, however, further experimental investigations at sites with different topographies, slopes, different land covers, which would allow a more comprehensive analysis of the processes underlying the occurrence of advective fluxes. The quantification of these processes would help to better quantify nocturnal

Synthesis, characterization, and application of Zn(NH 3)(CO3) for selective adsorptive separation of CO2

Science.gov (United States)

Khazeni, Naasser

This study explores the potential of Zn(NH3)(CO3) for selective CO2 separation. It develops a novel, highly controllable, single-pot synthesis approach based on urea hydrolysis and solvothermal aging to increase the feasibility of synthesizing Zn(NH3)(CO3), determines the structure of Zn(NH3)(CO3) in detail through single crystal X-ray diffraction and powder X-ray diffraction analyses, and performs adsorption analyses for the compound using CO2, N 2, H2, O2, and CH4 as adsorptives. Through adsorptive characterization, a systematic adsorbent selection screening is performed to assess the potential application of Zn(NH3)(CO 3) for adsorptive separation of CO2 from an upstream gas mixture of power generation, hydrogen production, and natural gas industries. Structural analysis shows Zn(NH3)(CO3) to have an inorganic helical framework that consists of a small helix of (ZnOCO) 2 and a large helix of (ZnOCO)4 with two ammines (NH 3) pendant from every other zinc. In terms of adsorption capacity and CO2 selectivity, Zn(NH3)(CO3) adsorbed 0.550 mmole/g CO2 at 293 K and 4500 mmHg, but only 0.047 mmole/g N 2, 0.084 mmole/g H2, 0.207 mmole/g 02, and 0.060 mmole/g CH4 at the same temperature and pressure. This behavior demonstrates considerable equilibrium selectivities - 36, 31, 63, and 11 - for separating CO2 from CH4, CO2 from H 2, CO2 from N2, and CO2 from 02, respectively. During adsorption, the pendant ammines act as the gates of check-valves: applied pressure opens the gates for adsorption; and during desorption, the gates are closed, trapping the adsorbates, until a reduction of pressure to near-atmospheric levels. Therefore, Zn(NH3)(CO3) exhibits low-pressure H3 or H4 hysteresis, indicating that the Zn(NH3)(CO3) framework can achieve gas storage at near-atmospheric pressures. Additionally, the compound proves structurally stable, with an adsorption decrease of 0.8% after 20 adsorption/desorption cycles - a factor that, considered with the other characteristics of Zn

ISLSCP II Globalview: Atmospheric CO2 Concentrations

Data.gov (United States)

National Aeronautics and Space Administration — The GlobalView Carbon Dioxide (CO2) data product contains synchronized and smoothed time series of atmospheric CO2 concentrations at selected sites that were created...

A Site Selection Model for a Straw-Based Power Generation Plant with CO2 Emissions

Directory of Open Access Journals (Sweden)

Hao Lv

2014-10-01

Full Text Available The decision on the location of a straw-based power generation plant has a great influence on the plant’s operation and performance. This study explores traditional theories for site selection. Using integer programming, the study optimizes the economic and carbon emission outcomes of straw-based power generation as two objectives, with the supply and demand of straw as constraints. It provides a multi-objective mixed-integer programming model to solve the site selection problem for a straw-based power generation plant. It then provides a case study to demonstrate the application of the model in the decision on the site selection for a straw-based power generation plant with a Chinese region. Finally, the paper discusses the result of the model in the context of the wider aspect of straw-based power generation.

Shaft sealing issue in CO2 storage sites

Science.gov (United States)

Dieudonné, A.-C.; Charlier, R.; Collin, F.

2012-04-01

Carbon capture and storage is an innovating approach to tackle climate changes through the reduction of greenhouse gas emissions. Deep saline aquifers, depleted oil and gas reservoirs and unmineable coal seams are among the most studied reservoirs. However other types of reservoir, such as abandonned coal mines, could also be used for the storage of carbon dioxide. In this case, the problem of shaft sealing appears to be particularly critical regarding to the economic, ecologic and health aspects of geological storage. The purpose of the work is to study shaft sealing in the framework of CO2 storage projects in abandoned coal mines. The problem of gas transfers around a sealing system is studied numerically using the finite elements code LAGAMINE, which has been developped for 30 years at the University of Liege. A coupled hydro-mechanical model of unsaturated geomaterials is used for the analyses. The response of the two-phase flow model is first studied through a simple synthetic problem consisting in the injection of gas in a concrete-made column. It stands out of this first modeling that the advection of the gas phase represents the main transfer mechanism of CO2 in highly unsaturated materials. Furthermore the setting of a bentonite barrier seal limits considerably the gas influx into the biosphere. A 2D axisymetric hydromechanical modeling of the Anderlues natural gas storage site is then performed. The geological and hydrogeological contexts of the site are used to define the problem, for the initial and boundary conditions, as well as the material properties. In order to reproduce stress and water saturation states in the shale before CO2 injection in the mine, different phases corresponding to the shaft sinking, the mining and the set up of the sealing system are simulated. The system efficiency is then evaluated by simulating the CO2 injection with the imposed pressure at the shaft wall. According to the modeling, the low water saturation of concrete and

A microporous MOF with a polar pore surface exhibiting excellent selective adsorption of CO2 from CO2-N2 and CO2-CH4 gas mixtures with high CO2 loading.

Science.gov (United States)

Pal, Arun; Chand, Santanu; Elahi, Syed Meheboob; Das, Madhab C

2017-11-14

A microporous MOF {[Zn(SDB)(L) 0.5 ]·S} n (IITKGP-5) with a polar pore surface has been constructed by the combination of a V-shaped -SO 2 functionalized organic linker (H 2 SDB = 4,4'-sulfonyldibenzoic acid) with an N-rich spacer (L = 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene), forming a network with sql(2,6L1) topology. IITKGP-5 is characterized by TGA, PXRD and single crystal X-ray diffraction. The framework exhibits lozenge-shaped channels of an approximate size of 4.2 × 5.6 Å 2 along the crystallographic b axis with a potential solvent accessible volume of 26%. The activated IITKGP-5a revealed a CO 2 uptake capacity of 56.4 and 49 cm 3 g -1 at 273 K/1 atm and 295 K/1 atm, respectively. On the contrary, it takes up a much smaller amount of CH 4 (17 cm 3 g -1 at 273 K and 13.6 cm 3 g -1 at 295 K) and N 2 (5.5 cm 3 g -1 at 273 K; 4 cm 3 g -1 at 295 K) under 1 atm pressure exhibiting its potential for a highly selective adsorption of CO 2 from flue gas as well as a landfill gas mixture. Based on the ideal adsorbed solution theory (IAST), a CO 2 /N 2 selectivity of 435.5 and a CO 2 /CH 4 selectivity of 151.6 have been realized at 273 K/100 kPa. The values at 295 K are 147.8 for CO 2 /N 2 and 23.8 for CO 2 /CH 4 gas mixtures under 100 kPa. In addition, this MOF nearly approaches the target values proposed for PSA and TSA processes for practical utility exhibiting its prospect for flue gas separation with a CO 2 loading capacity of 2.04 mmol g -1 .

Cu-Sn Bimetallic Catalyst for Selective Aqueous Electroreduction of CO2 to CO

KAUST Repository

Sarfraz, Saad; Garcia Esparza, Angel T.; Jedidi, Abdesslem; Cavallo, Luigi; Takanabe, Kazuhiro

2016-01-01

electrocatalyst generates a surface that inhibits adsorbed H*, resulting in improved CO FE. This study presents a strategy to provide a low-cost non-noble metals that can be utilized as a highly selective electrocatalyst for the efficient aqueous reduction of CO2.

Gasification under CO2–Steam Mixture: Kinetic Model Study Based on Shared Active Sites

Directory of Open Access Journals (Sweden)

Xia Liu

2017-11-01

Full Text Available In this work, char gasification of two coals (i.e., Shenfu bituminous coal and Zunyi anthracite and a petroleum coke under a steam and CO2 mixture (steam/CO2 partial pressures, 0.025–0.075 MPa; total pressures, 0.100 MPa and CO2/steam chemisorption of char samples were conducted in a Thermogravimetric Analyzer (TGA. Two conventional kinetic models exhibited difficulties in exactly fitting the experimental data of char–steam–CO2 gasification. Hence, a modified model based on Langmuir–Hinshelwood model and assuming that char–CO2 and char–steam reactions partially shared active sites was proposed and had indicated high accuracy for estimating the interactions in char–steam–CO2 reaction. Moreover, it was found that two new model parameters (respectively characterized as the amount ratio of shared active sites to total active sites in char–CO2 and char–steam reactions in the modified model hardly varied with gasification conditions, and the results of chemisorption indicate that these two new model parameters mainly depended on the carbon active sites in char samples.

Detection of CO{sub 2} using CNT-based sensors: Role of Fe catalyst on sensitivity and selectivity

Energy Technology Data Exchange (ETDEWEB)

Tit, Nacir, E-mail: ntit@uaeu.ac.ae [Physics Department, UAE University, P.O. Box 15551, Al-Ain (United Arab Emirates); Ezzi, Mohammed M. Al; Abdullah, Hasan M. [Physics Department, King Fahd University of Petroleum and Minerals, P.O. Box 1690, Dhahran, 31261 (Saudi Arabia); Yusupov, Maksudbek [Research Group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, BE-2610, Wilrijk-Antwerp (Belgium); Kouser, Summayya [Theoretical Sciences Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur, Bangalore (India); Bahlouli, Hocine [Physics Department, King Fahd University of Petroleum and Minerals, P.O. Box 1690, Dhahran, 31261 (Saudi Arabia); Yamani, Zain H. [Physics Department, King Fahd University of Petroleum and Minerals, P.O. Box 1690, Dhahran, 31261 (Saudi Arabia); Center for Research Excellence in Nanotechnology, KFUPM, P.O. Box 5040, Dhahran 31261 (Saudi Arabia)

2017-01-15

The adsorption of CO{sub 2} on surfaces of graphene and carbon nanotubes (CNTs), decorated with Fe atoms, are investigated using the self-consistent-charge density-functional tight-binding (SCC-DFTB) method, neglecting the heat effects. Fe ad-atoms are more stable when they are dispersed on hollow sites. They introduce a large density of states at the Fermi level (N{sub F}); where keeping such density low would help in gas sensing. Furthermore, the Fe ad-atom can weaken the C=O double bonds of the chemisorbed CO{sub 2} molecule, paving the way for oxygen atoms to drain more charges from Fe. Consequently, chemisorption of CO{sub 2} molecules reduces both N{sub F} and the conductance while it enhances the sensitivity with the increasing gas dose. Conducting armchair CNTs (ac-CNTs) have higher sensitivity than graphene and semiconducting zigzag CNTs (zz-CNTs). Comparative study of sensitivity of ac-CNT-Fe composite towards various gases (e.g., O{sub 2}, N{sub 2}, H{sub 2}, H{sub 2}O, CO and CO{sub 2}) has shown high sensitivity and selectivity towards CO, CO{sub 2} and H{sub 2}O gases. - Highlights: • DFTB is used to study Adsorptions of CO{sub 2} molecule on pG and CNT, with Fe catalyst. • Armchair CNT-Fe has higher sensitivity to detect CO{sub 2} than zigzag CNT-Fe and pG-Fe. • Ac-CNT-Fe is highly sensitive and selective towards CO, CO{sub 2} and H{sub 2}O gases. • Keeping Fe ad-atoms dispersed and with low density enhances sensitivity. • Our theoretical results corroborate the experimental findings of Ref. .

Implications of generator siting for CO2 pipeline infrastructure

International Nuclear Information System (INIS)

Newcomer, Adam; Apt, Jay

2008-01-01

The location of a new electric power generation system with carbon capture and sequestration (CCS) affects the profitability of the facility and determines the amount of infrastructure required to connect the plant to the larger world. Using a probabilistic analysis, we examine where a profit-maximizing power producer would locate a new generator with carbon capture in relation to a fuel source, electric load, and CO 2 sequestration site. Based on models of costs for transmission lines, CO 2 pipelines, and fuel transportation, we find that it is always preferable to locate a CCS power facility nearest the electric load, reducing the losses and costs of bulk electricity transmission. This result suggests that a power system with significant amounts of CCS requires a very large CO 2 pipeline infrastructure

Nanoporous amide networks based on tetraphenyladamantane for selective CO2capture

KAUST Repository

Zulfiqar, Sonia; Mantione, Daniele; El Tall, Omar; Sarwar, Muhammad Ilyas; Ruipé rez, Fernando; Rothenberger, Alexander; Mecerreyes, David

2016-01-01

Reduction of anthropogenic CO2 emissions and CO2 separation from post-combustion flue gases are among the imperative issues in the spotlight at present. Hence, it is highly desirable to develop efficient adsorbents for mitigating climate change with possible energy savings. Here, we report the design of a facile one pot catalyst-free synthetic protocol for the generation of three different nitrogen rich nanoporous amide networks (NANs) based on tetraphenyladamantane. Besides the porous architecture, CO2 capturing potential and high thermal stability, these NANs possess notable CO2/N2 selectivity with reasonable retention while increasing the temperature from 273 K to 298 K. The quantum chemical calculations also suggest that CO2 interacts mainly in the region of polar amide groups (-CONH-) present in NANs and this interaction is much stronger than that with N2 thus leading to better selectivity and affirming them as promising contenders for efficient gas separation. © The Royal Society of Chemistry 2016.

Nanoporous amide networks based on tetraphenyladamantane for selective CO2capture

KAUST Repository

Zulfiqar, Sonia

2016-04-19

Reduction of anthropogenic CO2 emissions and CO2 separation from post-combustion flue gases are among the imperative issues in the spotlight at present. Hence, it is highly desirable to develop efficient adsorbents for mitigating climate change with possible energy savings. Here, we report the design of a facile one pot catalyst-free synthetic protocol for the generation of three different nitrogen rich nanoporous amide networks (NANs) based on tetraphenyladamantane. Besides the porous architecture, CO2 capturing potential and high thermal stability, these NANs possess notable CO2/N2 selectivity with reasonable retention while increasing the temperature from 273 K to 298 K. The quantum chemical calculations also suggest that CO2 interacts mainly in the region of polar amide groups (-CONH-) present in NANs and this interaction is much stronger than that with N2 thus leading to better selectivity and affirming them as promising contenders for efficient gas separation. © The Royal Society of Chemistry 2016.

Adsorption Properties of MFM-400 and MFM-401 with CO2 and Hydrocarbons: Selectivity Derived from Directed Supramolecular Interactions.

Science.gov (United States)

Ibarra, Ilich A; Mace, Amber; Yang, Sihai; Sun, Junliang; Lee, Sukyung; Chang, Jong-San; Laaksonen, Aatto; Schröder, Martin; Zou, Xiaodong

2016-08-01

([Sc2(OH)2(BPTC)]) (H4BPTC = biphenyl-3,3',5,5'-tetracarboxylic acid), MFM-400 (MFM = Manchester Framework Material, previously designated NOTT), and ([Sc(OH)(TDA)]) (H2TDA = thiophene-2,5-dicarboxylic acid), MFM-401, both show selective and reversible capture of CO2. In particular, MFM-400 exhibits a reasonably high CO2 uptake at low pressures and competitive CO2/N2 selectivity coupled to a moderate isosteric heat of adsorption (Qst) for CO2 (29.5 kJ mol(-1)) at zero coverage, thus affording a facile uptake-release process. Grand canonical Monte Carlo (GCMC) and density functional theory (DFT) computational analyses of CO2 uptake in both materials confirmed preferential adsorption sites consistent with the higher CO2 uptake observed experimentally for MFM-400 over MFM-401 at low pressures. For MFM-400, the Sc-OH group participates in moderate interactions with CO2 (Qst = 33.5 kJ mol(-1)), and these are complemented by weak hydrogen-bonding interactions (O···H-C = 3.10-3.22 Å) from four surrounding aromatic -CH groups. In the case of MFM-401, adsorption is provided by cooperative interactions of CO2 with the Sc-OH group and one C-H group. The binding energies obtained by DFT analysis for the adsorption sites for both materials correlate well with the observed moderate isosteric heats of adsorption for CO2. GCMC simulations for both materials confirmed higher uptake of EtOH compared with nonpolar vapors of toluene and cyclohexane. This is in good correlation with the experimental data, and DFT analysis confirmed the formation of a strong hydrogen bond between EtOH and the hydrogen atom of the hydroxyl group of the MFM-400 and MFM-401 framework (FW) with H-OEtOH···H-OFW distances of 1.77 and 1.75 Å, respectively. In addition, the accessible regeneration of MFM-400 and MFM-401 and release of CO2 potentially provide minimal economic and environmental penalties.

Mixed matrix membranes with fast and selective transport pathways for efficient CO2 separation

Science.gov (United States)

Hou, Jinpeng; Li, Xueqin; Guo, Ruili; Zhang, Jianshu; Wang, Zhongming

2018-03-01

To improve CO2 separation performance, porous carbon nanosheets (PCNs) were used as a filler into a Pebax MH 1657 (Pebax) matrix, fabricating mixed matrix membranes (MMMs). The PCNs exhibited a preferential horizontal orientation within the Pebax matrix because of the extremely large 2D plane and nanoscale thickness of the matrix. Therefore, the micropores of the PCNs provided fast CO2 transport pathways, which led to increased CO2 permeability. The reduced pore size of the PCNs was a consequence of the overlapping of PCNs and the polymer chains penetrating into the pores of the PCNs. The reduction in the pore size of the PCNs improved the CO2/gas selectivity. As a result, the CO2 permeability and CO2/CH4 selectivity of the Pebax membrane with 10 wt% PCNs-loading (Pebax-PCNs-10) were 520 barrer and 51, respectively, for CO2/CH4 mixed-gas. The CO2 permeability and CO2/N2 selectivity of the Pebax-PCNs-10 membrane were 614 barrer and 61, respectively, for CO2/N2 mixed-gas.

Enthalpies of formation of selected Co{sub 2}YZ Heusler compounds

Energy Technology Data Exchange (ETDEWEB)

Yin, Ming, E-mail: myin1@hawk.iit.edu; Chen, Song; Nash, Philip

2013-11-15

Highlights: •Enthalpies of formation of selected Co{sub 2}YZ were measured by drop calorimeters. •Enthalpy decreases as the Z element approaches the top right corner of the periodic table. •For the Y element, enthalpy increases on increasing the number of d electrons. •Result of L2{sub 1} structured compounds agrees with first principles data. •Lattice parameters and related phase relationships were consistent with literature data. -- Abstract: Standard enthalpies of formation at 298 K of selected ternary Co{sub 2}-based Heusler compounds Co{sub 2}YZ (Y = Fe, Hf, Mn, Ti, V, Zr; Z = Al, Ga, In, Si, Ge, Sn) were measured by high temperature direct synthesis calorimetry. The measured enthalpies of formation (in kJ/mole of atoms) of the L2{sub 1} compounds are: Co{sub 2}FeGa (−25.8 ± 2.6); Co{sub 2}FeSi (−38.4 ± 2.2); Co{sub 2}FeGe (−11.6 ± 2.1); Co{sub 2}MnGa (−30.1 ± 2.3); Co{sub 2}MnSi (−42.4 ± 1.2); Co{sub 2}MnGe (−31.6 ± 3.0); Co{sub 2}MnSn (−15.6 ± 2.8); Co{sub 2}TiAl (−55.0 ± 3.7); Co{sub 2}TiGa (−54.2 ± 2.6); Co{sub 2}TiSi (−61.4 ± 1.7); Co{sub 2}TiGe (−59.3 ± 3.8); Co{sub 2}TiSn (−38.4 ± 2.0); Co{sub 2}VGa (−28.4 ± 1.1) and for the B2 compounds: Co{sub 2}FeAl (−22.5 ± 2.5), Co{sub 2}MnAl (−27.6 ± 2.7). Values are compared with those from first principles calculation when available and the extended semi-empirical model of Miedema. Trends in enthalpy of formation with element atomic number are discussed. Lattice parameters of the compounds with L2{sub 1} structure are determined by X-ray diffraction analysis.

CO2 Selective, Zeolitic Imidazolate Framework-7 Based Polymer Composite Mixed-Matrix Membranes

KAUST Repository

Chakrabarty, Tina; Neelakanda, Pradeep; Peinemann, Klaus-Viktor

2018-01-01

CO2 removal is necessary to mitigate the effects of global warming but it is a challenging process to separate CO2 from natural gas, biogas, and other gas streams. Development of hybrid membranes by use of polymers and metal-organic framework (MOF) particles is a viable option to overcome this challenge. A ZIF-7 nano-filler that was synthesized in our lab was embedded into a designed polymer matrix at various loadings and the performance of the mixed matrix membranes was evaluated in terms of gas permeance and selectivity. Hybrid membranes with various loadings (20, 30 and 40 wt%) were developed and tested at room temperature by a custom made time lag equipment and a jump in selectivity was observed when compared with the pristine polymer. A commercially attractive region for the selectivity CO2 over CH4 was achieved with a selectivity of 39 for 40 wt% particle loading. An increase in selectivity was observed with the increase of ZIF-7 loadings. Best performance was seen at 40% ZIF-7 loaded membrane with an ideal selectivity of 39 for CO2 over CH4. The obtained selectivity was 105% higher for CO2 over CH4 than the selectivity of the pristine polymer with a slight decrease in permeance. Morphological characterization of such developed membranes showed an excellent compatibility between the polymer and particle adhesion.

CO2 Selective, Zeolitic Imidazolate Framework-7 Based Polymer Composite Mixed-Matrix Membranes

KAUST Repository

Chakrabarty, Tina

2018-05-17

CO2 removal is necessary to mitigate the effects of global warming but it is a challenging process to separate CO2 from natural gas, biogas, and other gas streams. Development of hybrid membranes by use of polymers and metal-organic framework (MOF) particles is a viable option to overcome this challenge. A ZIF-7 nano-filler that was synthesized in our lab was embedded into a designed polymer matrix at various loadings and the performance of the mixed matrix membranes was evaluated in terms of gas permeance and selectivity. Hybrid membranes with various loadings (20, 30 and 40 wt%) were developed and tested at room temperature by a custom made time lag equipment and a jump in selectivity was observed when compared with the pristine polymer. A commercially attractive region for the selectivity CO2 over CH4 was achieved with a selectivity of 39 for 40 wt% particle loading. An increase in selectivity was observed with the increase of ZIF-7 loadings. Best performance was seen at 40% ZIF-7 loaded membrane with an ideal selectivity of 39 for CO2 over CH4. The obtained selectivity was 105% higher for CO2 over CH4 than the selectivity of the pristine polymer with a slight decrease in permeance. Morphological characterization of such developed membranes showed an excellent compatibility between the polymer and particle adhesion.

Study of the hyperfine magnetic field at Ta181 site in the Heusler Co2 Sc Sn, Co2 Sc Ga and Co2 Hf Sn alloys

International Nuclear Information System (INIS)

Attili, R.N.

1992-01-01

The hyperfine magnetic fields acting on 181 Ta nuclei at the Sc and Hf sites have been measured in Heusler alloys Co 2 Sc Sn and Co 2 Sc Ga and Co 2 Hf Sn using the Time Differential Perturbed γ-γ Angular Correlation (TDPAC) technique. The measurements were carried out using an automatic spectrometer consisting of two Ba F 2 detectors and the conventional electronics. The magnitude of hyperfine magnetic field at 181 Ta was measured for all the alloys. The signs of the were determined in the cases of Co 2 Sc Sn and Co 2 Hf Sn alloys by performing the Perturbed Angular Correlation measurements with an external polarizing magnetic field of ≅ 5 k Gauss. The hyperfine magnetic fields obtained are -187,6± 3,3 and 90,0 ± 2,1 kOe measured at 77 K for Co 2 Sc Sn and Co 2 Sc Ga alloys respectively, and -342,4 ± 10,1 kOe measured at the room temperature for Co 2 Hf Sn alloy. These results are discussed and compared with the hyperfine magnetic field systematics in Co-based Heusler alloy. (author)

Supramolecular Recognition Allows Remote, Site-Selective C-H Oxidation of Methylenic Sites in Linear Amines.

Science.gov (United States)

Olivo, Giorgio; Farinelli, Giulio; Barbieri, Alessia; Lanzalunga, Osvaldo; Di Stefano, Stefano; Costas, Miquel

2017-12-18

Site-selective C-H functionalization of aliphatic alkyl chains is a longstanding challenge in oxidation catalysis, given the comparable relative reactivity of the different methylenes. A supramolecular, bioinspired approach is described to address this challenge. A Mn complex able to catalyze C(sp 3 )-H hydroxylation with H 2 O 2 is equipped with 18-benzocrown-6 ether receptors that bind ammonium substrates via hydrogen bonding. Reversible pre-association of protonated primary aliphatic amines with the crown ether selectively exposes remote positions (C8 and C9) to the oxidizing unit, resulting in a site-selective oxidation. Remarkably, such control of selectivity retains its efficiency for a whole series of linear amines, overriding the intrinsic reactivity of C-H bonds, no matter the chain length. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Integrated basic treatment of activated carbon for enhanced CO{sub 2} selectivity

Energy Technology Data Exchange (ETDEWEB)

Adelodun, Adedeji Adebukola; Jo, Young-Min, E-mail: ymjo@khu.ac.kr

2013-12-01

We attempted the use of three chemical agents viz nitric acid (HN), calcium nitrate (CaN) and calcium ethanoate (CaEt) to achieve enhanced CO{sub 2} selective adsorption by activated carbon (AC). In dry phase treatment, microporous coconut shell-based carbon (CS) exhibits higher CO{sub 2} capacity than coal-based. However, upon wet-phase pre-treatment, modified CS samples showed lesser CO{sub 2} adsorption efficiency. Surface characterization with X-ray photoelectron spectroscopy confirms the presence of calcium and amine species on the samples with integrated treatment (A-CaN). These samples recorded the highest low-level CO{sub 2} capture despite calcinated CaEt-doped samples (C-CaEt) showing the highest value for pure and high level CO{sub 2} adsorption capacities. The slope and linearity values of isobaric desorption were used to estimate the proportion of CO{sub 2} chemisorbed and heterogeneity of the adsorbents’ surfaces respectively. Consequently, integrated basic impregnation provides the most efficient adsorbents for selective adsorption of both indoor and outdoor CO{sub 2} levels.

Probing surface sites of TiO2: reactions with [HRe(CO)5] and [CH3Re(CO)5].

Science.gov (United States)

Lobo-Lapidus, Rodrigo J; Gates, Bruce C

2010-10-04

Two carbonyl complexes of rhenium, [HRe(CO)(5)] and [CH(3)Re(CO)(5)], were used to probe surface sites of TiO(2) (anatase). These complexes were adsorbed from the gas phase onto anatase powder that had been treated in flowing O(2) or under vacuum to vary the density of surface OH sites. Infrared (IR) spectra demonstrate the variation in the number of sites, including Ti(+3)-OH and Ti(+4)-OH. IR and extended X-ray absorption fine structure (EXAFS) spectra show that chemisorption of the rhenium complexes led to their decarbonylation, with formation of surface-bound rhenium tricarbonyls, when [HRe(CO)(5)] was adsorbed, or rhenium tetracarbonyls, when [CH(3)Re(CO)(5)] was adsorbed. These reactions were accompanied by the formation of water and surface carbonates and removal of terminal hydroxyl groups associated with Ti(+3) and Ti(+4) ions on the anatase. Data characterizing the samples after adsorption of [HRe(CO)(5)] or [CH(3)Re(CO)(5)] determined a ranking of the reactivity of the surface OH sites, with the Ti(+3)-OH groups being the more reactive towards the rhenium complexes but the less likely to be dehydroxylated. The two rhenium pentacarbonyl probes provided complementary information, suggesting that the carbonate species originate from carbonyl ligands initially bonded to the rhenium and from hydroxyl groups of the titania surface, with the reaction leading to the formation of water and bridging hydroxyl groups on the titania. The results illustrate the value of using a family of organometallic complexes as probes of oxide surface sites.

The magnetic hyperfine field in the 181Ta site in the Co2HfAl and Co2HfGa Heusler alloys

International Nuclear Information System (INIS)

Silva, R. da.

1979-01-01

The hyperfine magnetic fields at 181 Ta nuclei in Heusler alloys Co 2 HfZ (Z=Al, Ga) have been measured using the time differential perturbed gamma-gamma angular correlation (TDPAC) method. The hyperfine fields obtained from these measurements at the liquid nitrogen temperature are -189 and +- 150 kOersted for Co 2 HfAl and Co 2 HfGa, respectively. The concept that the hyperfine field at the Y site is similar to the solute fields in Fe, Co, Ni and Gd matrices is corroborated. We have verified that ratios H sub(hf) sub(Ta)/T sub(c) and H sub(hf) sub(Ta)μ sub(Co) in Co 2 HfZ compounds (Z=Al, Ga, Sn) do not depend on the nature of Z element. However a dependence in the value of observed field with the s-p element in Z site was noticed. We feel that the samples are not completely ordered cubic as observed by the quadrupole interaction measurements. The results are interpreted in terms of the Campbell-Blandin formalism, and it is shown that the spin polarization of conduction electrons at Hf and Ta have opposite signs. (Author) [pt

Rigorous Screening Technology for Identifying Suitable CO2 Storage Sites II

Energy Technology Data Exchange (ETDEWEB)

George J. Koperna Jr.; Vello A. Kuuskraa; David E. Riestenberg; Aiysha Sultana; Tyler Van Leeuwen

2009-06-01

This report serves as the final technical report and users manual for the 'Rigorous Screening Technology for Identifying Suitable CO2 Storage Sites II SBIR project. Advanced Resources International has developed a screening tool by which users can technically screen, assess the storage capacity and quantify the costs of CO2 storage in four types of CO2 storage reservoirs. These include CO2-enhanced oil recovery reservoirs, depleted oil and gas fields (non-enhanced oil recovery candidates), deep coal seems that are amenable to CO2-enhanced methane recovery, and saline reservoirs. The screening function assessed whether the reservoir could likely serve as a safe, long-term CO2 storage reservoir. The storage capacity assessment uses rigorous reservoir simulation models to determine the timing, ultimate storage capacity, and potential for enhanced hydrocarbon recovery. Finally, the economic assessment function determines both the field-level and pipeline (transportation) costs for CO2 sequestration in a given reservoir. The screening tool has been peer reviewed at an Electrical Power Research Institute (EPRI) technical meeting in March 2009. A number of useful observations and recommendations emerged from the Workshop on the costs of CO2 transport and storage that could be readily incorporated into a commercial version of the Screening Tool in a Phase III SBIR.

A Nitrogen-Doped Carbon Catalyst for Electrochemical CO2 Conversion to CO with High Selectivity and Current Density.

Science.gov (United States)

Jhong, Huei-Ru Molly; Tornow, Claire E; Smid, Bretislav; Gewirth, Andrew A; Lyth, Stephen M; Kenis, Paul J A

2017-03-22

We report characterization of a non-precious metal-free catalyst for the electrochemical reduction of CO 2 to CO; namely, a pyrolyzed carbon nitride and multiwall carbon nanotube composite. This catalyst exhibits a high selectivity for production of CO over H 2 (approximately 98 % CO and 2 % H 2 ), as well as high activity in an electrochemical flow cell. The CO partial current density at intermediate cathode potentials (V=-1.46 V vs. Ag/AgCl) is up to 3.5× higher than state-of-the-art Ag nanoparticle-based catalysts, and the maximum current density is 90 mA cm -2 . The mass activity and energy efficiency (up to 48 %) were also higher than the Ag nanoparticle reference. Moving away from precious metal catalysts without sacrificing activity or selectivity may significantly enhance the prospects of electrochemical CO 2 reduction as an approach to reduce atmospheric CO 2 emissions or as a method for load-leveling in relation to the use of intermittent renewable energy sources. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Therapeutic benefits of carbon dioxide (CO2) laser on single-site HPV lesions in the lower female genital tract

Science.gov (United States)

Urru, Giovanni; Moretti, Gianfranco

1998-01-01

Numerous studies have shown contradictory variable percentages of recurrent HPV lesions, after various therapies. The present study therefore evaluates the effectiveness of CO2 laser vaporization in the treatment of single-site HPV lesions of the lower female genital tract in order to confirm the conviction that physical therapy alone, in agreement with some findings reported in the literature, is capable of guaranteeing a high cure rate in selected patients. From January 1995 to June 1996, seventy- five female patients were treated with CO2 laser vaporization for single-site genital HPV lesions, some of which were associated with low-grade intra-epithelial neoplasia. The success rate after 12 months proved to be 97%. The pre-existing clinical symptoms disappeared in all the patients treated. No complication in the vaporization procedure was encountered.

Constructing robust and highly-selective hydrogel membranes by bioadhesion-inspired method for CO 2 separation

KAUST Repository

Wu, Yingzhen; Zhou, Tiantian; Wu, Hong; Fu, Weixian; Wang, Xinru; Wang, Shaofei; Yang, Leixin; Wu, Xingyu; Ren, Yanxiong; Jiang, Zhongyi; Wang, Baoyi

2018-01-01

-size gas molecules and thus enhancing the CO2/CH4 selectivity. Moreover, the abundant amine groups from PDA nanoaggregates could facilitate CO2 transport. The optimized hybrid hydrogel membrane exhibited CO2/CH4 selectivity of 43.2, which was 43.85% higher

SiteChar – Methodology for a Fit-for-Purpose Assessment of CO2 Storage Sites in Europe

Directory of Open Access Journals (Sweden)

Delprat-Jannaud F.

2015-04-01

Full Text Available The FP7-funded SiteChar project examined the entire CO2 geological storage site characterisation process, from the initial feasibility studies through to the final stage of application for a CO2 storage permit based on criteria defined by the relevant European legislation. The SiteChar workflow for CO2 geological storage site characterisation provides a description of all elements of a site characterisation study, as well as guidance to streamline the site characterisation process and make sure that the output covers the aspects mentioned in the European Community (EC Storage Directive. Five potential European storage sites, representative of prospective geological contexts, were considered as test sites for the research work: a North Sea multi-store site (hydrocarbon field and aquifer offshore Scotland; an onshore aquifer in Denmark; an onshore gas field in Poland; an aquifer offshore in Norway; and an aquifer in the Southern Adriatic Sea. This portfolio combines complementary sites that allowed to encompass the different steps of the characterisation workflow. A key innovation was the development of internal ‘dry-run’ permit applications at the Danish and Scottish sites and their review by relevant regulatory authorities. This process helped to refine the site characterisation workflow, and aimed to identify remaining gaps in site-specific characterisation, needed to secure storage permits under the EC Storage Directive as implemented in ‘host’ Member States. SiteChar considered the important aspect of the public awareness and public opinions of these new technologies, in parallel to technical issues, on the onshore Polish and offshore Scottish sites. A new format to assist public opinion-forming processes was tested involving a small sample of local communities. Generic as well as site-specific information was made available to the general and local public via the internet and at information meetings. These exercises provide insight

The electrochemical selective reduction of NO using CoSe2@CNTs hybrid.

Science.gov (United States)

Liu, Hui; Xiang, Kaisong; Yang, Bentao; Xie, Xiaofeng; Wang, Dongli; Zhang, Cong; Liu, Zhilou; Yang, Shu; Liu, Cao; Zou, Jianping; Chai, Liyuan

2017-06-01

Converting the NO from gaseous pollutant into NH 4 + through electrocatalytical reduction using cost-effective materials holds great promise for pollutant purifying and resources recycling. In this work, we developed a highly selective and stable catalyst CoSe 2 nanoparticle hybridized with carbon nanotubes (CoSe 2 @CNTs). The CoSe 2 @CNTs hybrid catalysts performed an extraordinary high selectivity for NH 4 + formation in NO electroreduction with minimal N 2 O production and H 2 evolution. The specific spatial structure of CoSe 2 is conductive to the predominant formation of N-H bond between the N from adsorbed NO and H and inhibition of N-N formation from adjacent adsorbed NO. It was also the first time to convert the coordinated NO into NH 4 + using non-noble metal catalysis. Moreover, the original concept of employing CoSe 2 as eletrocatalyst for NO hydrogenation presented in this work can broaden horizons and provide new dimensions in the design of new highly efficient catalysts for NH 4 + synthesis in aqueous solution.

Site populations analysis of the Sm2(Co,Fe)17 alloys using Moessbauer spectroscopy

International Nuclear Information System (INIS)

Nagamine, L.C.C.M.

1990-01-01

Moessbauer measurements were carried out at room temperature for Sm 2 (Co 1-x Fe x ) 17 alloys with x=0,1 to 0,6 and Sm 2 (Co 0.9-v Fe v Cu 0.08 Zr 0.02 ) 8.35 , with v=0.23 to 0.27. All samples were characterized by x-ray diffraction. They showed rhombohedral structure of Th 2 Zn 17 type (R 3-bar m), where Fe atoms occupy four crystallographic sites. All spectra showed magnetic splitting and a high complexity resulting from the superposition of four Fe sites. Hyperfine parameters and site populations were obtained by least-squares fitting of the spectra. (author)

Experimental and Numerical Modelling of CO2 Atmospheric Dispersion in Hazardous Gas Emission Sites.

Science.gov (United States)

Gasparini, A.; sainz Gracia, A. S.; Grandia, F.; Bruno, J.

2015-12-01

Under stable atmospheric conditions and/or in presence of topographic depressions, CO2 concentrations can reach high values resulting in lethal effect to living organisms. The distribution of denser than air gases released from the underground is governed by gravity, turbulence and dispersion. Once emitted, the gas distribution is initially driven by buoyancy and a gas cloud accumulates on the ground (gravitational phase); with time the density gradient becomes less important due to dispersion or mixing and gas distribution is mainly governed by wind and atmospheric turbulence (passive dispersion phase). Natural analogues provide evidences of the impact of CO2 leakage. Dangerous CO2 concentration in atmosphere related to underground emission have been occasionally reported although the conditions favouring the persistence of such a concentration are barely studied.In this work, the dynamics of CO2 in the atmosphere after ground emission is assessed to quantify their potential risk. Two approaches have been followed: (1) direct measurement of air concentration in a natural emission site, where formation of a "CO2 lake" is common and (2) numerical atmospheric modelling. Two sites with different morphology were studied: (a) the Cañada Real site, a flat terrain in the Volcanic Field of Campo de Calatrava (Spain); (b) the Solforata di Pomezia site, a rough terrain in the Alban Hills Volcanic Region (Italy). The comparison between field data and model calculations reveal that numerical dispersion models are capable of predicting the formation of CO2 accumulation over the ground as a consequence of underground gas emission. Therefore, atmospheric modelling could be included as a valuable methodology in the risk assessment of leakage in natural degassing systems and in CCS projects. Conclusions from this work provide clues on whether leakage may be a real risk for humans and under which conditions this risk needs to be included in the risk assessment.

Nanoporous Cu–Al–Co Alloys for Selective Furfural Hydrodeoxygenation to 2-Methylfuran

Energy Technology Data Exchange (ETDEWEB)

Hutchings, Gregory S.; Luc, Wesley; Lu, Qi; Zhou, Yang; Vlachos, Dionisios G.; Jiao, Feng (Delaware)

2017-03-17

By finding new catalysts for selective and efficient conversion of biomass-derived products to industrially relevant chemicals and fuels, a transition from fossil fuel feedstocks may be achieved. Furfural (C₅H₄O₂) is a platform chemical which may be converted to multiple heterocyclic and ring-opening products, but to date there have been few catalysts which enable selective hydrodeoxygenation to 2-methylfuran (2-MF, C₅H₆O). Here, we present a self-supported nanoporous Cu–Al–Co ternary alloy catalyst with high furfural HDO activity toward 2-MF, achieving up to 66.0% selectivity and 98.2% overall conversion at 513 K with only a ~5 atomic % Co composition. Some further analysis over multiple temperature conditions and nominal Co concentrations was performed to examine optimal conditions and tune catalyst performance, and operando X-ray absorption spectroscopy experiments were conducted to elucidate the structure of the catalyst in the reaction environment.

Adaptive evolution of the spike gene of SARS coronavirus: changes in positively selected sites in different epidemic groups

Directory of Open Access Journals (Sweden)

He Shao-Heng

2006-10-01

Full Text Available Abstract Background It is believed that animal-to-human transmission of severe acute respiratory syndrome (SARS coronavirus (CoV is the cause of the SARS outbreak worldwide. The spike (S protein is one of the best characterized proteins of SARS-CoV, which plays a key role in SARS-CoV overcoming species barrier and accomplishing interspecies transmission from animals to humans, suggesting that it may be the major target of selective pressure. However, the process of adaptive evolution of S protein and the exact positively selected sites associated with this process remain unknown. Results By investigating the adaptive evolution of S protein, we identified twelve amino acid sites (75, 239, 244, 311, 479, 609, 613, 743, 765, 778, 1148, and 1163 in the S protein under positive selective pressure. Based on phylogenetic tree and epidemiological investigation, SARS outbreak was divided into three epidemic groups: 02–04 interspecies, 03-early-mid, and 03-late epidemic groups in the present study. Positive selection was detected in the first two groups, which represent the course of SARS-CoV interspecies transmission and of viral adaptation to human host, respectively. In contrast, purifying selection was detected in 03-late group. These indicate that S protein experiences variable positive selective pressures before reaching stabilization. A total of 25 sites in 02–04 interspecies epidemic group and 16 sites in 03-early-mid epidemic group were identified under positive selection. The identified sites were different between these two groups except for site 239, which suggests that positively selected sites are changeable between groups. Moreover, it was showed that a larger proportion (24% of positively selected sites was located in receptor-binding domain (RBD than in heptad repeat (HR1-HR2 region in 02–04 interspecies epidemic group (p = 0.0208, and a greater percentage (25% of these sites occurred in HR1–HR2 region than in RBD in 03-early

BOREAS TGB-1 Soil CH4 and CO2 Profile Data from NSA Tower Sites

Science.gov (United States)

Crill, Patrick; Varner, Ruth K.; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

2000-01-01

The BOREAS TGB-1 team made numerous measurements of trace gas concentrations and fluxes at various NSA sites. This data set contains methane (CH4) and carbon dioxide (CO2) concentrations in soil profiles from the NSA-OJP, NSA-OBS, NSA-YJP, and NSA-BP sites during the period of 23-May to 20-Sep-1994. The soil gas sampling profiles of CH 4 and CO 2 were completed to quantify controls on CO2 and CH4 fluxes in the boreal forest. The data are provided in tabular ASCII files.

Solubility and selectivity of CO2 in ether-functionalized imidazolium ionic liquids

International Nuclear Information System (INIS)

Zhou, Lingyun; Shang, Xiaomin; Fan, Jing; Wang, Jianji

2016-01-01

Highlights: • Solubilities of CO 2 , N 2 and O 2 in [EOMmim][PF 6 ] and [EOMmim][Tf 2 N] were determined. • Introduction of ether group results in increase of CO 2 /N 2 and CO 2 /O 2 selectivity. • The solution of CO 2 in the ionic liquids is an exothermic and orderly process. • Experimental solubility data have been well correlated by Pitzer model. - Abstract: Ionic liquids are widely recognized new materials in carbon dioxide capture and separation technology. In this work, we synthesized and characterized two kinds of ether-functionalized imidazolium ionic liquids, 1-methoxyethyl-3-methylimidazolium hexafluoroborate ([EOMmim][PF 6 ]) and 1-methoxyethyl-3-methylimidazolium bis(trifluoro-methylsulfony)imide ([EOMmim][Tf 2 N]). Solubility values of CO 2 in these ionic liquids were determined by isometric weight method at the temperatures from 298.15 K to 343.15 K and the pressure up to 5.185 MPa. Furthermore, solubilities of other flue gases, N 2 and O 2 , in these two ionic liquids were also measured at 303.15 K. It was shown that little influence had been exerted on CO 2 solubility by the introduction of ether groups on the cation, but it decreased N 2 and O 2 solubility, resulting in the remarkable increase of CO 2 /N 2 and CO 2 /O 2 selectivity. In addition, the solubility data were well correlated by Pitzer model, and the standard state solution Gibbs energy, solution enthalpy and solution entropy of CO 2 in the two ionic liquids were reported. Regeneration characteristics of the investigated ionic liquids was also studied by vacuum desorption and atmospheric desorption, respectively.

Distorted chain sites for Co- and Fe-substituted YBa2Cu3O/sub 7-δ/

International Nuclear Information System (INIS)

Bridges, F.; Boyce, J.B.; Claeson, T.; Geballe, T.H.; Tarascon, J.M.; Xerox Palo Alto Research Center, Palo Alto, California 94304; Physics Department, Chalmers University of Technology, S-41296 Gothenburg, Sweden; Department of Applied Physics, Stanford University, Stanford, California 94305; Bell Communications Research Laboratory, Red Bank, New Jersey 07701)

1989-01-01

We present x-ray-absorption fine-structure (XAFS) measurements for a series of Co- and Fe-substituted samples of YBa 2 Cu 3 O/sub 7-δ/(Y-Ba-Cu-O). Our analysis of the first- and second-neighbor environments indicates that the Co atoms primarily replace the Cu in the chain sites, the Cu(1) atoms, in Y-Ba-Cu-O, but many of these Co(1) sites and their neighboring oxygen sites are highly distorted. The first-neighbor Co-O peak consists of approximately 3.5 oxygen at 1.8 A and approximately 1.3 oxygen at 2.4 A, while the second-neighbor multipeak in the XAFS data is unexpectedly low in amplitude. Structure in this peak is inconsistent with a simple Gaussian broadening and indicates that several Co(1)-Ba distances exist. We propose an aggregation of the Co atoms into distorted, zigzag chains along the directions, with some of the Co displaced off center by approximately 0.4 A along a perpendicular direction. This model is consistent with the second-neighbor XAFS data, provides an explanation for the tetragonal structure via twinning on a microscopic scale, and accommodates excess oxygen within the Co chains. The Fe data suggest that similar chains also exist in the Fe-substituted samples. There are, however, some differences between the local environments of the Fe and Co. The primary difference is that a small but significant number of Fe atoms occupy the Cu(2) plane sites while no appreciable number of Co atoms are found on the Cu(2) sites in the more dilute samples. Finally, near-edge measurements on the Co and Fe K-absorption edges indicate that the valence is primarily +3, but a mixture of valences exists. For Co the edge position corresponds to a mixture of +2 and +3 valences, while Fe exists in a mixture of +2, +3, and +4 states

Engineering Cu surfaces for the electrocatalytic conversion of CO2: Controlling selectivity toward oxygenates and hydrocarbons

Science.gov (United States)

Hahn, Christopher; Hatsukade, Toru; Kim, Youn-Geun; Vailionis, Arturas; Baricuatro, Jack H.; Higgins, Drew C.; Nitopi, Stephanie A.; Soriaga, Manuel P.; Jaramillo, Thomas F.

2017-01-01

In this study we control the surface structure of Cu thin-film catalysts to probe the relationship between active sites and catalytic activity for the electroreduction of CO2 to fuels and chemicals. Here, we report physical vapor deposition of Cu thin films on large-format (∼6 cm2) single-crystal substrates, and confirm epitaxial growth in the , , and orientations using X-ray pole figures. To understand the relationship between the bulk and surface structures, in situ electrochemical scanning tunneling microscopy was conducted on Cu(100), (111), and (751) thin films. The studies revealed that Cu(100) and (111) have surface adlattices that are identical to the bulk structure, and that Cu(751) has a heterogeneous kinked surface with (110) terraces that is closely related to the bulk structure. Electrochemical CO2 reduction testing showed that whereas both Cu(100) and (751) thin films are more active and selective for C–C coupling than Cu(111), Cu(751) is the most selective for >2e− oxygenate formation at low overpotentials. Our results demonstrate that epitaxy can be used to grow single-crystal analogous materials as large-format electrodes that provide insights on controlling electrocatalytic activity and selectivity for this reaction. PMID:28533377

Porous carbon derived via KOH activation of a hypercrosslinked porous organic polymer for efficient CO_2, CH_4, H_2 adsorptions and high CO_2/N_2 selectivity

International Nuclear Information System (INIS)

Modak, Arindam; Bhaumik, Asim

2015-01-01

Microporous carbon having Brunauer-Emmett-Teller (BET) surface area of 2186 m"2 g"−"1 and micropore volume of 0.85 cm"3 g"−"1 has been synthesized via KOH induced high temperature carbonization of a non-conjugated hypercrosslinked organic polymer. Owing to the templating and activation by KOH, we have succeeded in making a microporous carbon from this porous polymer and the resultant carbon material showed high uptake for CO_2 (7.6 mmol g"−"1) and CH_4 (2.4 mmol g"−"1) at 1 atm, 273 K together with very good selectivity for the CO_2/N_2 (30.2) separation. Furthermore, low pressure (1 atm) H_2 (2.6 wt%, 77 K) and water uptake (57.4 wt%, 298 K) ability of this polymer derived porous activated carbon is noteworthy. - Graphical abstract: Microporous carbon with BET surface area of 2186 m"2 g"−"1 has been synthesized via KOH activation of a porous organic polymer and it showed high uptake for CO_2 (7.6 mmol g"−"1), CH_4 (2.4 mmol g"−"1) and H_2 (2.6 wt%) at 1 atm together with very good selectivity for CO_2. - Highlights: • Porous carbon from hypercrosslinked organic polymer. • KOH activated carbon with BET surface area 2186 m"2 g"−"1. • High CO2 uptake (7.6 mmol g"−"1) and CO_2/N_2 selectivity (30.2). • Porous carbon also showed high H_2 (2.6 wt%) and H_2O (57.4 wt%) uptakes.

Evaluation of the impact of H2O, O2, and SO2 on postcombustion CO2 capture in metal-organic frameworks.

Science.gov (United States)

Yu, Jiamei; Ma, Yuguang; Balbuena, Perla B

2012-05-29

Molecular modeling methods are used to estimate the influence of impurity species: water, O(2), and SO(2) in flue gas mixtures present in postcombustion CO(2) capture using a metal organic framework, HKUST-1, as a model sorbent material. Coordinated and uncoordinated water effects on CO(2) capture are analyzed. Increase of CO(2) adsorption is observed for both cases, which can be attributed to the enhanced binding energy between CO(2) and HKUST-1 due to the introduction of a small amount of water. Density functional theory calculations indicate that the binding energy between CO(2) and HKUST-1 with coordinated water is ~1 kcal/mol higher than that without coordinated water. It is found that the improvement of CO(2)/N(2) selectivity induced by coordinated water may mainly be attributed to the increased CO(2) adsorption on the hydrated HKUST-1. On the other hand, the enhanced selectivity induced by uncoordinated water in the flue gas mixture can be explained on the basis of the competition of adsorption sites between water and CO(2) (N(2)). At low pressures, a significant CO(2)/N(2) selectivity increase is due to the increase of CO(2) adsorption and decrease of N(2) adsorption as a consequence of competition of adsorption sites between water and N(2). However, with more water molecules adsorbed at higher pressures, the competition between water and CO(2) leads to the decrease of CO(2) adsorption capacity. Therefore, high pressure operation should be avoided in HKUST-1 sorbents for CO(2) capture. In addition, the effects of O(2) and SO(2) on CO(2) capture in HKUST-1 are investigated: The CO(2)/N(2) selectivity does not change much even with relatively high concentrations of O(2) in the flue gas (up to 8%). A slightly lower CO(2)/N(2) selectivity of a CO(2)/N(2)/H(2)O/SO(2) mixture is observed compared with that in a CO(2)/N(2)/H(2)O mixture, especially at high pressures, due to the strong SO(2) binding with HKUST-1.

Simulation of a Potential CO2 Storage in the West Paris Basin: Site Characterization and Assessment of the Long-Term Hydrodynamical and Geochemical Impacts Induced by the CO2 Injection

Directory of Open Access Journals (Sweden)

Estublier Audrey

2017-07-01

Full Text Available This article presents the preliminary results of a study carried out as part of a demonstration project of CO2 storage in the Paris Basin. This project funded by ADEME (French Environment and Energy Management Agency and several industrial partners (TOTAL, ENGIE, EDF, Lafarge, Air Liquide, Vallourec aimed to study the possibility to set up an experimental infrastructure of CO2 transport and storage. Regarding the storage, the objectives were: (1 to characterize the selected site by optimizing the number of wells in a CO2 injection case of 200 Mt over 50 years in the Trias, (2 to simulate over time the CO2 migration and the induced pressure field, and (3 to analyze the geochemical behavior of the rock over the long term (1,000 years. The preliminary site characterization study revealed that only the southern area of Keuper succeeds to satisfy this injection criterion using only four injectors. However, a complementary study based on a refined fluid flow model with additional secondary faults concluded that this zone presents the highest potential of CO2 injection but without reaching the objective of 200 Mt with a reasonable number of wells. The simulation of the base scenario, carried out before the model refinement, showed that the overpressure above 0.1 MPa covers an area of 51,869 km2 in the Chaunoy formation, 1,000 years after the end of the injection, which corresponds to the whole West Paris Basin, whereas the CO2 plume extension remains small (524 km2. This overpressure causes brine flows at the domain boundaries and a local overpressure in the studied oil fields. Regarding the preliminary risk analysis of this project, the geochemical effects induced by the CO2 injection were studied by simulating the fluid-rock interactions with a coupled geochemical and fluid flow model in a domain limited to the storage complex. A one-way coupling of two models based on two domains fitting into each other was developed using dynamic boundary

Composites of ionic liquid and amine-modified SAPO 34 improve CO2 separation of CO2-selective polymer membranes

Science.gov (United States)

Hu, Leiqing; Cheng, Jun; Li, Yannan; Liu, Jianzhong; Zhang, Li; Zhou, Junhu; Cen, Kefa

2017-07-01

Mixed matrix membranes with ionic liquids and molecular sieve particles had high CO2 permeabilities, but CO2 separation from small gas molecules such as H2 was dissatisfied because of bad interfacial interaction between ionic liquid and molecular sieve particles. To solve that, amine groups were introduced to modify surface of molecular sieve particles before loading with ionic liquid. SAPO 34 was adopted as the original filler, and four mixed matrix membranes with different fillers were prepared on the outer surface of ceramic hollow fibers. Both surface voids and hard agglomerations disappeared, and the surface became smooth after SAPO 34 was modified by amine groups and ionic liquid [P66614][2-Op]. Mixed matrix membranes with composites of amine-modified SAPO 34 and ionic liquid exhibited excellent CO2 permeability (408.9 Barrers) and CO2/H2 selectivity (22.1).

Ground deformation monitoring using RADARSAT-2 DInSAR-MSBAS at the Aquistore CO2 storage site in Saskatchewan (Canada)

Science.gov (United States)

Czarnogorska, M.; Samsonov, S.; White, D.

2014-11-01

The research objectives of the Aquistore CO2 storage project are to design, adapt, and test non-seismic monitoring methods for measurement, and verification of CO2 storage, and to integrate data to determine subsurface fluid distributions, pressure changes and associated surface deformation. Aquistore site is located near Estevan in Southern Saskatchewan on the South flank of the Souris River and west of the Boundary Dam Power Station and the historical part of Estevan coal mine in southeastern Saskatchewan, Canada. Several monitoring techniques were employed in the study area including advanced satellite Differential Interferometric Synthetic Aperture Radar (DInSAR) technique, GPS, tiltmeters and piezometers. The targeted CO2 injection zones are within the Winnipeg and Deadwood formations located at > 3000 m depth. An array of monitoring techniques was employed in the study area including advanced satellite Differential Interferometric Synthetic Aperture Radar (DInSAR) with established corner reflectors, GPS, tiltmeters and piezometers stations. We used airborne LIDAR data for topographic phase estimation, and DInSAR product geocoding. Ground deformation maps have been calculated using Multidimensional Small Baseline Subset (MSBAS) methodology from 134 RADARSAT-2 images, from five different beams, acquired during 20120612-20140706. We computed and interpreted nine time series for selected places. MSBAS results indicate slow ground deformation up to 1 cm/year not related to CO2 injection but caused by various natural and anthropogenic causes.

A perfluorinated covalent triazine-based framework for highly selective and water-tolerant CO2 capture

KAUST Repository

Zhao, Yunfeng

2013-01-01

We designed and synthesized a perfluorinated covalent triazine-based framework (FCTF-1) for selective CO2 capture. The incorporation of fluorine (F) groups played multiple roles in improving the framework\\'s CO 2 adsorption and separation capabilities. Thermodynamically, the strongly polar C-F bonds promoted CO2 adsorption via electrostatic interactions, especially at low pressures. FCTF-1\\'s CO2 uptake was 1.76 mmol g-1 at 273 K and 0.1 bar through equilibrium adsorption, exceeding the CO2 adsorption capacity of any reported porous organic polymers to date. In addition, incorporating F groups produced a significant amount of ultra-micropores (<0.5 nm), which offered not only high gas adsorption potential but also kinetic selectivity for CO2-N 2 separation. In mixed-gas breakthrough experiments, FCTF-1 exhibited an exceptional CO2-N2 selectivity of 77 under kinetic flow conditions, much higher than the selectivity (31) predicted from single-gas equilibrium adsorption data. Moreover, FCTF-1 proved to be tolerant to water and its CO2 capture performance remained excellent when there was moisture in the gas mixture, due to the hydrophobic nature of the C-F bonds. In addition, the moderate adsorbate-adsorbent interaction allowed it to be fully regenerated by pressure swing adsorption processes. These attributes make FCTF-1 a promising sorbent for CO2 capture from flue gas. © 2013 The Royal Society of Chemistry.

Advances in Geological CO{sub 2} Sequestration and Co-Sequestration with O{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Verba, Circe A; O& #x27; Connor, William K.; Ideker, J.H.

2012-10-28

The injection of CO{sub 2} for Enhanced Oil Recovery (EOR) and sequestration in brine-bearing formations for long term storage has been in practice or under investigation in many locations globally. This study focused on the assessment of cement wellbore seal integrity in CO{sub 2}- and CO{sub 2}-O{sub 2}-saturated brine and supercritical CO{sub 2} environments. Brine chemistries (NaCl, MgCl{sub 2}, CaCl{sub 2}) at various saline concentrations were investigated at a pressure of 28.9 MPa (4200 psi) at both 50{degree}C and 85{degree}C. These parameters were selected to simulate downhole conditions at several potential CO{sub 2} injection sites in the United States. Class H portland cement is not thermodynamically stable under these conditions and the formation of carbonic acid degrades the cement. Dissociation occurs and leaches cations, forming a CaCO{sub 3} buffered zone, amorphous silica, and other secondary minerals. Increased temperature affected the structure of C-S-H and the hydration of the cement leading to higher degradation rates.

On the mechanism of high product selectivity for HCOOH using Pb in CO2 electroreduction.

Science.gov (United States)

Back, Seoin; Kim, Jun-Hyuk; Kim, Yong-Tae; Jung, Yousung

2016-04-14

While achieving high product selectivity is one of the major challenges of the CO2 electroreduction technology in general, Pb is one of the few examples with high selectivity that produces formic acid almost exclusively (versus H2, CO, or other byproducts). In this work, we study the mechanism of CO2 electroreduction reactions using Pb to understand the origin of high formic acid selectivity. In particular, we first assess the proton-assisted mechanism proposed in the literature using density functional calculations and find that it cannot fully explain the previous selectivity experiments for the Pb electrode. We then suggest an alternative proton-coupled-electron-transfer mechanism consistent with existing observations, and further validate a new mechanism by experimentally measuring and comparing the onset potentials for CO2 reduction vs. H2 production. We find that the origin of a high selectivity of the Pb catalyst for HCOOH production over CO and H2 lies in the strong O-affinitive and weak C-, H-affinitive characteristics of Pb, leading to the involvement of the *OCHO species as a key intermediate to produce HCOOH exclusively and preventing unwanted H2 production at the same time.

Electrocatalytic Alloys for CO2 Reduction.

Science.gov (United States)

He, Jingfu; Johnson, Noah J J; Huang, Aoxue; Berlinguette, Curtis P

2018-01-10

Electrochemically reducing CO 2 using renewable energy is a contemporary global challenge that will only be met with electrocatalysts capable of efficiently converting CO 2 into fuels and chemicals with high selectivity. Although many different metals and morphologies have been tested for CO 2 electrocatalysis over the last several decades, relatively limited attention has been committed to the study of alloys for this application. Alloying is a promising method to tailor the geometric and electric environments of active sites. The parameter space for discovering new alloys for CO 2 electrocatalysis is particularly large because of the myriad products that can be formed during CO 2 reduction. In this Minireview, mixed-metal electrocatalyst compositions that have been evaluated for CO 2 reduction are summarized. A distillation of the structure-property relationships gleaned from this survey are intended to help in the construction of guidelines for discovering new classes of alloys for the CO 2 reduction reaction. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exceptionally High Efficient Co-Co2P@N, P-Codoped Carbon Hybrid Catalyst for Visible Light-Driven CO2-to-CO Conversion.

Science.gov (United States)

Fu, Wen Gan

2018-05-02

Artificial photosynthesis has attracted wide attention, particularly the development of efficient solar light-driven methods to reduce CO2 to form energy-rich carbon-based products. Because CO2 reduction is an uphill process with a large energy barrier, suitable catalysts are necessary to achieve this transformation. In addition, CO2 adsorption on a catalyst and proton transfer to CO2 are two important factors for the conversion reaction，and catalysts with high surface area and more active sites are required to improve the efficiency of CO2 reduction. Here, we report a visible light-driven system for CO2-to-CO conversion that consists of a heterogeneous hybrid catalyst of Co and Co2P nanoparticles embedded in carbon nanolayers codoped with N and P (Co-Co2P@NPC) and a homogeneous Ru(II)-based complex photosensitizer. The average generation rate of CO of the system was up to 35,000 μmol h-1 g-1 with selectivity of 79.1% in 3 h. Linear CO production at an exceptionally high rate of 63,000 μmol h-1 g-1 was observed in the first hour of reaction. Inspired by this highly active catalyst, we also synthesized Co@NC and Co2P@NPC materials and explored their structure, morphology, and catalytic properties for CO2 photoreduction. The results showed that the nanoparticle size, partially adsorbed H2O molecules on the catalyst surface, and the hybrid nature of the systems influenced their photocatalytic CO2 reduction performance. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

CO and NO2 Selective Monitoring by ZnO-Based Sensors

Directory of Open Access Journals (Sweden)

Nicola Donato

2013-07-01

Full Text Available ZnO nanomaterials with different shapes were synthesized, characterized and tested in the selective monitoring of low concentration of CO and NO2 in air. ZnO nanoparticles (NPs and nanofibers (NFs were synthesized by a modified sol-gel method in supercritical conditions and electrospinning technique, respectively. CO and NO2 sensing tests have demonstrated that the annealing temperature and shape of zinc oxide nanomaterials are the key factors in modulating the electrical and sensing properties. Specifically, ZnO NPs annealed at high temperature (700 °C have been found sensitive to CO, while they displayed negligible response to NO2. The opposite behavior has been registered for the one-dimensional ZnO NFs annealed at medium temperature (400 °C. Due to their adaptable sensitivity/selectivity characteristics, the developed sensors show promising applications in dual air quality control systems for closed ambient such as automotive cabin, parking garage and tunnels.

Preliminary Safety and Risk HSE Assessment. Application to the Potential Locations of a CO2 Geological Storage Pilot

International Nuclear Information System (INIS)

Recreo, F.; Eguilior, S.; Ruiz, C.; Lomba, L.; Hurtado, A.

2015-01-01

The location of a site safe and able to sequester CO2 for long periods of time is essential to gain public acceptance. This requires a long-term safety assessment developed in a robust and reliable framework. Site selection is the first step and requires specific research. This paper describes the application of the Selection and Classification Method of Geological Formations (SCF) developed to assess the potential of geological formations to CO2 storage. This assessment is based in the analysis of risks to Health, Safety and Environment (HSE) derived from potential CO2 leakage. Comparisons of the results obtained from a number of potential sites can help to select the best candidate for CO2 injection. The potential impact will be related to three key potential features of CO2 geological storage: the potential of the target geological formation for long term CO2 containment; the potential for secondary containment on containment failure of the target formation; and the site's potential to mitigate and/or disperse CO2 leakage if the primary and secondary containments fail. The methodology assesses each of these three characteristics through an analysis and assessment of properties of certain attributes of them. Uncertainty will remain as an input and output value of the methodology due to the usual lack of data in most site selection processes. The global uncertainty reports on the trust on the knowledge of the site characteristics. Therefore, the methodology enables comparing sites taking into account both the HSE risk expectation and the estimation of the quality of knowledge concerning such risk. The objective is to contribute to the selection of potential sites for a CO2 injection pilot plant in the Iberian Peninsula from the perspective of Safety and Risk Analysis.

Site characterization of the highest-priority geologic formations for CO₂ storage in Wyoming

Energy Technology Data Exchange (ETDEWEB)

Surdam, Ronald C. [Univ. of Wyoming, Laramie, WY (United States); Bentley, Ramsey [Univ. of Wyoming, Laramie, WY (United States); Campbell-Stone, Erin [Univ. of Wyoming, Laramie, WY (United States); Dahl, Shanna [Univ. of Wyoming, Laramie, WY (United States); Deiss, Allory [Univ. of Wyoming, Laramie, WY (United States); Ganshin, Yuri [Univ. of Wyoming, Laramie, WY (United States); Jiao, Zunsheng [Univ. of Wyoming, Laramie, WY (United States); Kaszuba, John [Univ. of Wyoming, Laramie, WY (United States); Mallick, Subhashis [Univ. of Wyoming, Laramie, WY (United States); McLaughlin, Fred [Univ. of Wyoming, Laramie, WY (United States); Myers, James [Univ. of Wyoming, Laramie, WY (United States); Quillinan, Scott [Univ. of Wyoming, Laramie, WY (United States)

2013-12-07

This study, funded by U.S. Department of Energy National Energy Technology Laboratory award DE-FE0002142 along with the state of Wyoming, uses outcrop and core observations, a diverse electric log suite, a VSP survey, in-bore testing (DST, injection tests, and fluid sampling), a variety of rock/fluid analyses, and a wide range of seismic attributes derived from a 3-D seismic survey to thoroughly characterize the highest-potential storage reservoirs and confining layers at the premier CO₂ geological storage site in Wyoming. An accurate site characterization was essential to assessing the following critical aspects of the storage site: (1) more accurately estimate the CO₂ reservoir storage capacity (Madison Limestone and Weber Sandstone at the Rock Springs Uplift (RSU)), (2) evaluate the distribution, long-term integrity, and permanence of the confining layers, (3) manage CO₂ injection pressures by removing formation fluids (brine production/treatment), and (4) evaluate potential utilization of the stored CO₂

Selective production of oxygenates from CO2 hydrogenation over mesoporous silica supported Cu-Ga nanocomposite catalyst

KAUST Repository

Huang, Kuo-Wei

2017-11-23

Carbon dioxide hydrogenation to oxygenates (methanol and dimethyl ether (DME)) was investigated over bifunctional supported copper catalysts promoted with gallium (Ga). Supported Cu-Ga nanocomposite catalysts were characterized by X-ray diffraction, transmission electron microscopy with energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and H2 temperature programmed reduction. In comparison with Cu-SBA-15 based catalysts, Ga promoted catalysts prepared by the urea deposition method (CuGa/SBA-15-UDP) was found active and selective for CO2 hydrogenation to oxygenates. The use of Ga as the promoter showed increased acidic sites as confirmed by the NH3-TPD, Pyridine-IR and 2,6-lutidine-IR studies. The favorable effect of Ga on CO2 conversion and selectivity to oxygenate may come from the strong interaction of Ga with silica, which is responsible for the enhanced metal surface area, formation of nanocomposite and metal dispersion. Notably, incorporation of Ga to Cu/SiO2 showed a several-fold higher rate for methanol formation (13.12 mol/gCu·sec) with a reasonable rate for the DME formation (2.15 mol/gCu·sec) as compared to those of Cu/SiO2 catalysts.

Shape-Dependent Electrocatalytic Reduction of CO2 to CO on Triangular Silver Nanoplates.

Science.gov (United States)

Liu, Subiao; Tao, Hongbiao; Zeng, Li; Liu, Qi; Xu, Zhenghe; Liu, Qingxia; Luo, Jing-Li

2017-02-15

Electrochemical reduction of CO 2 (CO 2 RR) provides great potential for intermittent renewable energy storage. This study demonstrates a predominant shape-dependent electrocatalytic reduction of CO 2 to CO on triangular silver nanoplates (Tri-Ag-NPs) in 0.1 M KHCO 3 . Compared with similarly sized Ag nanoparticles (SS-Ag-NPs) and bulk Ag, Tri-Ag-NPs exhibited an enhanced current density and significantly improved Faradaic efficiency (96.8%) and energy efficiency (61.7%), together with a considerable durability (7 days). Additionally, CO starts to be observed at an ultralow overpotential of 96 mV, further confirming the superiority of Tri-Ag-NPs as a catalyst for CO 2 RR toward CO formation. Density functional theory calculations reveal that the significantly enhanced electrocatalytic activity and selectivity at lowered overpotential originate from the shape-controlled structure. This not only provides the optimum edge-to-corner ratio but also dominates at the facet of Ag(100) where it requires lower energy to initiate the rate-determining step. This study demonstrates a promising approach to tune electrocatalytic activity and selectivity of metal catalysts for CO 2 RR by creating optimal facet and edge site through shape-control synthesis.

Methanation of CO2 over Zeolite-Encapsulated Nickel Nanoparticles

DEFF Research Database (Denmark)

Goodarzi, Farnoosh; Kang, Liqun; Wang, Feng Ryan

2018-01-01

in an increased metal dispersion and, consequently, a high catalytic activity for CO2 methanation. With a gas hourly space velocity of 60000 ml/g catalyst h-1 and H2/CO2=4, the zeolite-encapsulated Ni nanoparticles result in 60% conversion at 450°C, which corresponds to a site-time yield of around 304 mol CH4/mol......Efficient methanation of CO2 relies on the development of more selective and stable heterogeneous catalysts. Here we present a simple and effective method to encapsulate Ni nanoparticles in zeolite silicalite-1. In this method, the zeolite is modified by selective desilication, which creates intra...

Potential hazards of CO2 leakage in storage systems : learning from natural systems

International Nuclear Information System (INIS)

Beaubien, S.E.; Lombardi, S.; Ciotoli, G.; Annunziatellis, A.; Hatziyannis, G.; Metaxas, A.; Pearce, J.M.

2005-01-01

The Natural Analogues for the Storage of CO2 in the Geological Environment (NASCENT) Project has examined several naturally occurring carbon dioxide (CO 2 ) deposits throughout Europe to better understand the possible long term geological effects of a man-made CO 2 storage reservoir. Natural geological accumulations of CO 2 also occur widely throughout the world, some of which leak CO 2 to the surface, while others are effectively sealed. It is important to understanding the characteristics of both types of deposits in order to select and design underground storage sites for CO 2 storage. Four naturally occurring CO 2 sites were reviewed in this paper with reference to issues related to risk assessment, such as migration pathways; the speed of migration and mass flux rates; changes in groundwater chemistry; and, the effects these emissions may have on local populations and ecosystems. One site was located in northern Greece, near the Florina CO 2 gas field. The other three sites were in central Italy, including a selected area of the Latera geothermal complex, where natural deep CO 2 migrates upwards along faults and is emitted to the atmosphere; the San Vittorino intermontane basin where CO 2 -charged groundwaters cause the dissolution of limestone to form large sinkholes; and, the Ciampino area southeast of Rome, where CO 2 from deep-seated volcanism migrates along faults in a residential area. Work performed on these sites included soil gas, CO 2 flux and aqueous geochemical surveys. A GIS based model was also developed for the Latera site to assesses the risk of deep gas migration to surface. It was emphasized that these 4 sites are extreme cases compared to a man-made CO 2 geological storage site. For example all sites have an essentially infinite supply of deep CO 2 as the result of the thermo-metamorphic reactions forming this gas, whereas a man-made storage site would have a finite volume of gas which would be limited in its mass transfer out of the

Novel porous carbon materials with ultrahigh nitrogen contents for selective CO 2 capture

KAUST Repository

Zhao, Yunfeng; Zhao, Lan; Yao, Kexin; Yang, Yang; Zhang, Qiang; Han, Yu

2012-01-01

Nitrogen-doped carbon materials were prepared by a nanocasting route using tri-continuous mesoporous silica IBN-9 as a hard template. Rationally choosing carbon precursors and carefully controlling activation conditions result in an optimized material denoted as IBN9-NC1-A, which possesses a very high nitrogen doping concentration (∼13 wt%) and a large surface area of 890 m 2 g -1 arising from micropores (<1 nm). It exhibits an excellent performance for CO 2 adsorption over a wide range of CO 2 pressures. Specifically, its equilibrium CO 2 adsorption capacity at 25 °C reaches up to 4.50 mmol g -1 at 1 bar and 10.53 mmol g -1 at 8 bar. In particular, it shows a much higher CO 2 uptake at low pressure (e.g. 1.75 mmol g -1 at 25 °C and 0.2 bar) than any reported carbon-based materials, owing to its unprecedented nitrogen doping level. The high nitrogen contents also give rise to significantly enhanced CO 2/N 2 selectivities (up to 42), which combined with the high adsorption capacities, make these new carbon materials promising sorbents for selective CO 2 capture from power plant flue gas and other relevant applications. © 2012 The Royal Society of Chemistry.

Single cobalt sites in mesoporous N-doped carbon matrix for selective catalytic hydrogenation of nitroarenes

KAUST Repository

Sun, Xiaohui

2017-11-20

A supported cobalt catalyst with atomically dispersed Co-Nx sites (3.5 wt% Co) in a mesoporous N-doped carbon matrix (named Co@mesoNC) is synthesized by hydrolysis of tetramethyl orthosilicate (TMOS) in a Zn/Co bimetallic zeolitic imidazolate framework (BIMZIF(Co,Zn)), followed by high-temperature pyrolysis and SiO2 leaching. A combination of TEM, XRD XPS and X-ray absorption spectroscopy studies confirm the absence of cobalt nanoparticles and indicate that these highly dispersed cobalt species are present in the form of Co-Nx. The exclusive formation of Co-Nx sites in the carbon matrix is attributed to the presence of a large amount of Zn and N in the BIMZIF precursor together with the presence of SiO2 in the pore space of this framework, extending the initial spatial distance between cobalt atoms and thereby impeding their agglomeration. The presence of SiO2 during high-temperature pyrolysis is proven crucial to create mesoporosity and a high BET area and pore volume in the N-doped carbon support (1780 m2 g−1, 1.54 cm3 g−1). This heterogeneous Co@mesoNC catalyst displays high activity and selectivity (>99%) for the selective hydrogenation of nitrobenzene to aniline at mild conditions (0.5–3 MPa, 343–383 K). When more challenging substrates (functionalized nitroarenes) are hydrogenated, the catalyst Co@mesoNC displays an excellent chemoselectivity to the corresponding substituted anilines.The presence of mesoporosity improves mass transport of reactants and/or products and the accessibility of the active Co-Nx sites, and greatly reduces deactivation due to fouling.

Single cobalt sites in mesoporous N-doped carbon matrix for selective catalytic hydrogenation of nitroarenes

KAUST Repository

Sun, Xiaohui; Olivos-Suarez, Alma I.; Osadchii, Dmitrii; Romero, Maria Jose Valero; Kapteijn, Freek; Gascon, Jorge

2017-01-01

A supported cobalt catalyst with atomically dispersed Co-Nx sites (3.5 wt% Co) in a mesoporous N-doped carbon matrix (named Co@mesoNC) is synthesized by hydrolysis of tetramethyl orthosilicate (TMOS) in a Zn/Co bimetallic zeolitic imidazolate framework (BIMZIF(Co,Zn)), followed by high-temperature pyrolysis and SiO2 leaching. A combination of TEM, XRD XPS and X-ray absorption spectroscopy studies confirm the absence of cobalt nanoparticles and indicate that these highly dispersed cobalt species are present in the form of Co-Nx. The exclusive formation of Co-Nx sites in the carbon matrix is attributed to the presence of a large amount of Zn and N in the BIMZIF precursor together with the presence of SiO2 in the pore space of this framework, extending the initial spatial distance between cobalt atoms and thereby impeding their agglomeration. The presence of SiO2 during high-temperature pyrolysis is proven crucial to create mesoporosity and a high BET area and pore volume in the N-doped carbon support (1780 m2 g−1, 1.54 cm3 g−1). This heterogeneous Co@mesoNC catalyst displays high activity and selectivity (>99%) for the selective hydrogenation of nitrobenzene to aniline at mild conditions (0.5–3 MPa, 343–383 K). When more challenging substrates (functionalized nitroarenes) are hydrogenated, the catalyst Co@mesoNC displays an excellent chemoselectivity to the corresponding substituted anilines.The presence of mesoporosity improves mass transport of reactants and/or products and the accessibility of the active Co-Nx sites, and greatly reduces deactivation due to fouling.

Surface-downhole and crosshole geoelectrics for monitoring of brine injection at the Ketzin CO2 storage site

Science.gov (United States)

Rippe, Dennis; Bergmann, Peter; Labitzke, Tim; Wagner, Florian; Schmidt-Hattenberger, Cornelia

2016-04-01

The Ketzin pilot site in Germany is the longest operating on-shore CO2 storage site in Europe. From June 2008 till August 2013, a total of ˜67,000 tonnes of CO2 were safely stored in a saline aquifer at depths of 630 m to 650 m. The storage site has now entered the abandonment phase, and continuation of the multi-disciplinary monitoring as part of the national project "CO2 post-injection monitoring and post-closure phase at the Ketzin pilot site" (COMPLETE) provides the unique chance to participate in the conclusion of the complete life cycle of a CO2 storage site. As part of the continuous evaluation of the functionality and integrity of the CO2 storage in Ketzin, from October 12, 2015 till January 6, 2015 a total of ˜2,900 tonnes of brine were successfully injected into the CO2 reservoir, hereby simulating in time-lapse the natural backflow of brine and the associated displacement of CO2. The main objectives of this brine injection experiment include investigation of how much of the CO2 in the pore space can be displaced by brine and if this displacement of CO2 during the brine injection differs from the displacement of formation fluid during the initial CO2 injection. Geophysical monitoring of the brine injection included continuous geoelectric measurements accompanied by monitoring of pressure and temperature conditions in the injection well and two adjacent observation wells. During the previous CO2 injection, the geoelectrical monitoring concept at the Ketzin pilot site consisted of permanent crosshole measurements and non-permanent large-scale surveys (Kiessling et al., 2010). Time-lapse geoelectrical tomographies derived from the weekly crosshole data at near-wellbore scale complemented by six surface-downhole surveys at a scale of 1.5 km showed a noticeable resistivity signature within the target storage zone, which was attributed to the CO2 plume (Schmidt-Hattenberger et al., 2011) and interpreted in terms of relative CO2 and brine saturations (Bergmann

Effects of CO2 gas as leaks from geological storage sites on agro-ecosystems

DEFF Research Database (Denmark)

Patil, Ravi; Colls, Jeremy J; Steven, Michael D

2010-01-01

Carbon capture and storage in geological formations has potential risks in the long-term safety because of the possibility of CO2 leakage. Effects of leaking gas, therefore, on vegetation, soil, and soil-inhabiting organisms are critical to understand. An artificial soil gassing and response...... detection field facility developed at the University of Nottingham was used to inject CO2 gas at a controlled flow rate (1 l min-1) into soil to simulate build-up of soil CO2 concentrations and surface fluxes from two land use types: pasture grassland, and fallow followed by winter bean. Mean soil CO2....... This study showed adverse effects of CO2 gas on agro-ecosystem in case of leakage from storage sites to surface....

Equilibration of metabolic CO2 with preformed CO2 and bicarbonate

International Nuclear Information System (INIS)

Hems, R.; Saez, G.T.

1983-01-01

Entry of metabolic 14 CO 2 into urea is shown to occur more readily than it equilibrates with the general pool of cellular plus extracellular bicarbonate plus CO 2 . Since the sites of CO 2 production (pyruvate dehydrogenase and oxoglutarate dehydrogenase) and of fixation (carbamoylphosphate synthetase) are intramitochondrial, it is likely that the fixation of CO 2 is also more rapid than its equilibration with the cytoplasmic pool of bicarbonate plus CO 2 . This observation may point to a more general problem concerning the interpretation of isotope data, with compartmentation or proximity of sites of production and utilisation of metabolites may result in the isotope following a preferred pathway. (Auth.)

Screening and ranking framework (SRF) for geologic CO2 storagesite selection on the basis of HSE risk

Energy Technology Data Exchange (ETDEWEB)

Oldenburg, Curtis M.

2006-11-27

A screening and ranking framework (SRF) has been developedto evaluate potential geologic carbon dioxide (CO2) storage sites on thebasis of health, safety, and environmental (HSE) risk arising from CO2leakage. The approach is based on the assumption that CO2 leakage risk isdependent on three basic characteristics of a geologic CO2 storage site:(1) the potential for primary containment by the target formation; (2)the potential for secondary containment if the primary formation leaks;and (3) the potential for attenuation and dispersion of leaking CO2 ifthe primary formation leaks and secondary containment fails. Theframework is implemented in a spreadsheet in which users enter numericalscores representing expert opinions or published information along withestimates of uncertainty. Applications to three sites in Californiademonstrate the approach. Refinements and extensions are possible throughthe use of more detailed data or model results in place of propertyproxies.

GHGT-10 : Assessing the integrity of fault- and top seals at CO2 storage sites

NARCIS (Netherlands)

Orlic, B.; Heege J.H. ter; Wassing, B.

2011-01-01

Induced stress changes due to CO2 injection into geological reservoirs can mechanically damage bounding fault- and top seals creating preferential pathways for CO2 migration from the containment or trigger existing faults causing seismic activity at storage sites. In this paper we present

From Site Characterization through Safe and Successful CO2 Injection Operation to Post-injection Monitoring and Site Closure - Closing the Full Life Cycle Research at the Ketzin Pilot Site, Germany

Science.gov (United States)

Liebscher, Axel

2017-04-01

Initiated in 2004, the Ketzin pilot site near Berlin, Germany, was the first European onshore storage project for research and development on geological CO2 storage. After comprehensive site characterization the site infrastructure was build comprising three deep wells and the injection facility including pumps and storage tanks. The operational CO2 injection period started in June 2008 and ended in August 2013 when the site entered the post-injection closure period. During these five years, a total amount of 67 kt of CO2 was safely injected into an Upper Triassic saline sandstone aquifer at a depth of 630 m - 650 m. In fall 2013, the first observation well was partially plugged in the reservoir section with CO2 resistant cement; full abandonment of this well finished in 2015 after roughly 2 years of cement plug monitoring. Abandonment of the remaining wells will be finished by summer 2017 and hand-over of liability to the competent authority is scheduled for end of 2017. The CO2 injected was mainly of food grade quality (purity > 99.9%). In addition, 1.5 kt of CO2 from the oxyfuel pilot capture facility "Schwarze Pumpe" (purity > 99.7%) was injected in 2011. The injection period terminated with a CO2-N2 co-injection experiment of 650 t of a 95% CO2/5% N2 mixture in summer 2013 to study the effects of impurities in the CO2 stream on the injection operation. During regular operation, the CO2 was pre-heated on-site to 40°C prior to injection to ensure a single-phase injection process and avoid any phase transition or transient states within the injection facility or the reservoir. Between March and July 2013, just prior to the CO2-N2 co-injection experiment, the injection temperature was stepwise decreased down to 10°C within a "cold-injection" experiment to study the effects of two-phase injection conditions. During injection operation, the combination of different geochemical and geophysical monitoring methods enabled detection and mapping of the spatial and

Synthesis of basalt fiber@Zn1-xMgxO core/shell nanostructures for selective photoreduction of CO2 to CO

Science.gov (United States)

Kwak, Byeong Sub; Kim, Kang Min; Park, Sun-Min; Kang, Misook

2017-06-01

This study focused on the development of a catalyst for converting carbon dioxide, the main cause of global warming, into a beneficial energy source. Core@shell structured particles, BF@ZnO and BF@Zn1-xMgxO, are synthesized in order to selectively obtain CO gas from the photoreduction of CO2. A modified sol-gel process is used to synthesize the core@shell structures with a three-dimensional microstructure, which are subsequently characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDAX), ultraviolet (UV)-vis absorption, photoluminescence (PL), and photocurrent density analysis. The CO2 adsorption abilities of the core@shell particles are estimated through CO2-temperature programmed desorption (TPD). The core@shell structured BF@Zn1-xMgxO particles including the Mg ingredient significantly increased the adsorption of CO2 gas at the microfiber/nanoparticle interface. Both the BF@ZnO and BF@Zn1-xMgxO particles selectively reduce the carbon dioxide to carbon monoxide, with almost no other reduced products being observed. These results are attributed to the effective adsorption of CO2 gas and inhibited recombination of the photogenerated electron-hole pairs. BF@Zn0.75Mg0.25O exhibited superior photocatalytic behavior and selectively produced 5.0 μmolgcat-1 L-1 of CO gas after 8 h of reaction.

Constructing robust and highly-selective hydrogel membranes by bioadhesion-inspired method for CO 2 separation

KAUST Repository

Wu, Yingzhen

2018-06-01

Water-swollen hydrogel membranes are good candidates for CO2 separations due to the favorable solubility of CO2 in water. However, the excessive amount of water often causes the poor mechanical property and low selectivity. Herein, we propose a bioadhesion-inspired method to construct robust and high-performance CO2 separation membranes via in situ generation of polydopamine (PDA) nanoaggregates within poly (vinyl alcohol) (PVA) matrix. PDA nanoaggregates entangled with PVA chains and formed hydrogen bonding with hydroxyl groups from PVA chains. Physical cross-linking occurred between PVA chains and PDA nanoaggregates. Compared with the PVA membrane, the PVA-PDA hybrid membrane with the dopamine content of 0.5mol% exhibited a 1.7-fold increase in tensile strength and a 2.2-fold increase in the tensile modulus. The membranes were used for CO2/CH4 separation. The physical cross-linking resulted in a PVA chain rigidification region around PDA nanoaggregates, which hindered the penetration of larger-size gas molecules and thus enhancing the CO2/CH4 selectivity. Moreover, the abundant amine groups from PDA nanoaggregates could facilitate CO2 transport. The optimized hybrid hydrogel membrane exhibited CO2/CH4 selectivity of 43.2, which was 43.85% higher than that of the PVA membrane. The bioadhesion-inspired method opens up new opportunities to exploit the potential application of hydrogel membranes.

Coupled Metal/Oxide Catalysts with Tunable Product Selectivity for Electrocatalytic CO2 Reduction.

Science.gov (United States)

Huo, Shengjuan; Weng, Zhe; Wu, Zishan; Zhong, Yiren; Wu, Yueshen; Fang, Jianhui; Wang, Hailiang

2017-08-30

One major challenge to the electrochemical conversion of CO 2 to useful fuels and chemical products is the lack of efficient catalysts that can selectively direct the reaction to one desirable product and avoid the other possible side products. Making use of strong metal/oxide interactions has recently been demonstrated to be effective in enhancing electrocatalysis in the liquid phase. Here, we report one of the first systematic studies on composition-dependent influences of metal/oxide interactions on electrocatalytic CO 2 reduction, utilizing Cu/SnO x heterostructured nanoparticles supported on carbon nanotubes (CNTs) as a model catalyst system. By adjusting the Cu/Sn ratio in the catalyst material structure, we can tune the products of the CO 2 electrocatalytic reduction reaction from hydrocarbon-favorable to CO-selective to formic acid-dominant. In the Cu-rich regime, SnO x dramatically alters the catalytic behavior of Cu. The Cu/SnO x -CNT catalyst containing 6.2% of SnO x converts CO 2 to CO with a high faradaic efficiency (FE) of 89% and a j CO of 11.3 mA·cm -2 at -0.99 V versus reversible hydrogen electrode, in stark contrast to the Cu-CNT catalyst on which ethylene and methane are the main products for CO 2 reduction. In the Sn-rich regime, Cu modifies the catalytic properties of SnO x . The Cu/SnO x -CNT catalyst containing 30.2% of SnO x reduces CO 2 to formic acid with an FE of 77% and a j HCOOH of 4.0 mA·cm -2 at -0.99 V, outperforming the SnO x -CNT catalyst which only converts CO 2 to formic acid in an FE of 48%.

Aircraft vertical profiling of variation of CO2 over a Canadian Boreal Forest Site: a role of advection in the changes in the atmospheric boundary layer CO2 content

International Nuclear Information System (INIS)

Shashkov, Alexander; Higuchi, Kaz; Chan, Douglas

2007-01-01

During the period of July 8-13, 2002, we collected vertical profiles by aircraft of meteorological variables and atmospheric CO 2 over the OBS (old black spruce) site located in Boreal Ecosystem Research and Monitoring Sites in Northern Saskatchewan, Canada. We have used the data from the morning and afternoon flights to calculate the regional daily afternoon CO 2 flux for the days July 8-11. These daily fluxes were then compared to those obtained by the boundary layer budget method and by the eddy covariance measurements on the tower at the OBS site. We identified the importance of changes in the CO 2 concentration by advection to the flux estimates. In addition, we provide arguments to suggest that subseasonal temporal averaging might not, at least in some cases, eliminate advective bias contribution to the flux estimates. Because the advective influence is large and highly directional, even on seasonal and interannual timescales, it is advisable that flux estimates based on CO 2 concentration change at a site contain dynamic description of an air parcel transport history

Verification of geomechanical integrity and prediction of long-term mineral trapping for the Ketzin CO2 storage pilot site

Science.gov (United States)

Kempka, Thomas; De Lucia, Marco; Kühn, Michael

2014-05-01

Static and dynamic numerical modelling generally accompany the entire CO2 storage site life cycle. Thereto, it is required to match the employed models with field observations on a regular basis in order to predict future site behaviour. We investigated the coupled processes at the Ketzin CO2 storage pilot site [1] using a model coupling concept focusing on the temporal relevance of processes involved (hydraulic, chemical and mechanical) at given time-scales (site operation, abandonment and long-term stabilization). For that purpose, long-term dynamic multi-phase flow simulations [2], [3] established the basis for all simulations discussed in the following. Hereby, pressure changes resulting in geomechanical effects are largest during site operation, whereas geochemical reactions are governed by slow kinetics resulting in a long-term stabilization. To account for mechanical integrity, which may be mainly affected during site operation, we incorporated a regional-scale coupled hydro-mechanical model. Our simulation results show maximum ground surface displacements of about 4 mm, whereas shear and tensile failure are not observed. Consequently, the CO2 storage operation at the Ketzin pilot site does not compromise reservoir, caprock and fault integrity. Chemical processes responsible for mineral trapping are expected to mainly occur during long-term stabilization at the Ketzin pilot site [4]. Hence, our previous assessment [3] was extended by integrating two long-term mineral trapping scenarios. Thereby, mineral trapping contributes to the trapping mechanisms with 11.7 % after 16,000 years of simulation in our conservative and with 30.9 % in our maximum reactivity scenarios. Dynamic flow simulations indicate that only 0.2 % of the CO2 injected (about 67,270 t CO2 in total) is in gaseous state, but structurally trapped after 16,000 years. Depending on the studied long-term scenario, CO2 dissolution is the dominating trapping mechanism with 68.9 % and 88

Enhanced binding affinity, remarkable selectivity, and high capacity of CO 2 by dual functionalization of a rht-type metal-organic framework

KAUST Repository

Li, Baiyan

2011-12-23

Open and friendly: The smallest member of the rht-type metal-organic frameworks (MOFs, see picture) constructed by a hexacarboxylate ligand with a nitrogen-rich imino triazine backbone shows a significantly enhanced gas binding affinity relative to all other isoreticular rht-type MOFs. The high adsorption capacity and remarkable selectivity of CO 2 are attributed to the high density of open metal and Lewis basic sites in the framework. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Impact of CO_2 on the Evolution of Microbial Communities Exposed to Carbon Storage Conditions, Enhanced Oil Recovery, and CO_2 Leakage

International Nuclear Information System (INIS)

Gulliver, Djuna M.; Gregory, Kelvin B.; Lowry, Gregory V.

2016-01-01

Geologic carbon storage (GCS) is a crucial part of a proposed mitigation strategy to reduce the anthropogenic carbon dioxide (CO_2) emissions to the atmosphere. During this process, CO_2 is injected as super critical carbon dioxide (SC-CO_2) in confined deep subsurface storage units, such as saline aquifers and depleted oil reservoirs. The deposition of vast amounts of CO_2 in subsurface geologic formations could unintentionally lead to CO_2 leakage into overlying freshwater aquifers. Introduction of CO_2 into these subsurface environments will greatly increase the CO_2 concentration and will create CO_2 concentration gradients that drive changes in the microbial communities present. While it is expected that altered microbial communities will impact the biogeochemistry of the subsurface, there is no information available on how CO_2 gradients will impact these communities. The overarching goal of this project is to understand how CO_2 exposure will impact subsurface microbial communities at temperatures and pressures that are relevant to GCS and CO_2 leakage scenarios. To meet this goal, unfiltered, aqueous samples from a deep saline aquifer, a depleted oil reservoir, and a fresh water aquifer were exposed to varied concentrations of CO_2 at reservoir pressure and temperature. The microbial ecology of the samples was examined using molecular, DNA-based techniques. The results from these studies were also compared across the sites to determine any existing trends. Results reveal that increasing CO_2 leads to decreased DNA concentrations regardless of the site, suggesting that microbial processes will be significantly hindered or absent nearest the CO_2 injection/leakage plume where CO_2 concentrations are highest. At CO_2 exposures expected downgradient from the CO_2 plume, selected microorganisms emerged as dominant in the CO_2 exposed conditions. Results suggest that the altered microbial community was site specific and highly dependent on pH. The site

Chemistry of fluids from a natural analogue for a geological CO{sub 2} storage site (Montmiral, France): Lessons for CO{sub 2}-water-rock interaction assessment and monitoring

Energy Technology Data Exchange (ETDEWEB)

Pauwels, Helene [BRGM - Water Division, 3, av Claude Guillemin, 45060 Orleans Cedex (France)], E-mail: h.pauwels@brgm.fr; Gaus, Irina; Le Nindre, Yves Michel [BRGM - Water Division, 3, av Claude Guillemin, 45060 Orleans Cedex (France); Pearce, Jonathan [British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham NG125GG (United Kingdom); Czernichowski-Lauriol, Isabelle [BRGM - Water Division, 3, av Claude Guillemin, 45060 Orleans Cedex (France)

2007-12-15

Chemical and isotope studies of natural CO{sub 2} accumulations aid in assessing the chemical effects of CO{sub 2} on rock and thus provide a potential for understanding the long-term geochemical processes involved in CO{sub 2} geological storage. Several natural CO{sub 2} accumulations were discovered during gas and oil exploration in France's carbogaseous peri-Alpine province (south-eastern France) in the 1960s. One of these, the Montmiral accumulation at a depth of more than 2400 m, is currently being exploited. The chemical composition of the water collected at the wellhead has changed in time and the final salinity exceeds 75 g/L. These changes in time can be explained by assuming that the fraction of the reservoir brine in the recovered brine-CO{sub 2}-H{sub 2}O mixture varies, resulting in variable proportions of H{sub 2}O and brine in the sampled water. The proportions can be estimated in selected samples due to the availability of gas and water flowrate data. These data enabled the reconstruction of the chemical and isotope composition of the brine. The proportions of H{sub 2}O and brine can also be estimated from isotope ({delta}{sup 2}H, {delta}{sup 18}O) composition of collected water and {delta}{sup 18}O of the sulfates or CO{sub 2}. The reconstituted brine has a salinity of more than 85 g/L and, according to its Br{sup -} content and isotope ({delta}{sup 2}H, {delta}{sup 18}O, {delta}{sup 34}S) composition, originates from an evaporated Triassic seawater that underwent dilution by meteoric water. The reconstitution of the brine's chemical composition enabled an evaluation of the CO{sub 2}-water-rock interactions based on: (1) mineral saturation indices; and (2) comparison with initial evaporated Triassic seawater. Dissolution of K- and SO{sub 4}-containing minerals such as K-feldspar and anhydrite, and precipitation of Ca and Mg containing minerals that are able to trap CO{sub 2} (carbonates) are highlighted. The changes in concentration of

CO2 and its correlation with CO at a rural site near Beijing: implications for combustion efficiency in China

Directory of Open Access Journals (Sweden)

H. Ma

2010-09-01

Full Text Available Although China has surpassed the United States as the world's largest carbon dioxide emitter, in situ measurements of atmospheric CO2 have been sparse in China. This paper analyzes hourly CO2 and its correlation with CO at Miyun, a rural site near Beijing, over a period of 51 months (Dec 2004 through Feb 2009. The CO2-CO correlation analysis evaluated separately for each hour of the day provides useful information with statistical significance even in the growing season. We found that the intercept, representing the initial condition imposed by global distribution of CO2 with influence of photosynthesis and respiration, exhibits diurnal cycles differing by season. The background CO2 (CO2,b derived from Miyun observations is comparable to CO2 observed at a Mongolian background station to the northwest. Annual growth of overall mean CO2 at Miyun is estimated at 2.7 ppm yr−1 while that of CO2,b is only 1.7 ppm yr−1 similar to the mean growth rate at northern mid-latitude background stations. This suggests a relatively faster increase in the regional CO2 sources in China than the global average, consistent with bottom-up studies of CO2 emissions. For air masses with trajectories through the northern China boundary layer, mean winter CO2/CO correlation slopes (dCO2/dCO increased by 2.8 ± 0.9 ppmv/ppmv or 11% from 2005–2006 to 2007–2008, with CO2 increasing by 1.8 ppmv. The increase in dCO2/dCO indicates improvement in overall combustion efficiency over northern China after winter 2007, attributed to pollution reduction measures associated with the 2008 Beijing Olympics. The observed CO2/CO ratio at Miyun is 25% higher than the bottom-up CO2/CO emission ratio, suggesting a contribution of respired CO2 from urban residents as well as agricultural soils and livestock in the observations and uncertainty in the emission estimates.

Tailoring gas-phase CO2 electroreduction selectivity to hydrocarbons at Cu nanoparticles

Science.gov (United States)

Merino-Garcia, I.; Albo, J.; Irabien, A.

2018-01-01

Copper-based surfaces appear as the most active catalysts for CO2 electroreduction to hydrocarbons, even though formation rates and efficiencies still need to be improved. The aim of the present work is to evaluate the continuous gas-phase CO2 electroreduction to hydrocarbons (i.e. ethylene and methane) at copper nanoparticulated-based surfaces, paying attention to particle size influence (ranging from 25-80 nm) on reaction productivity, selectivity, and Faraday efficiency (FE) for CO2 conversion. The effect of the current density and the presence of a microporous layer within the working electrode are then evaluated. Copper-based gas diffusion electrodes are prepared by airbrushing the catalytic ink onto carbon supports, which are then coupled to a cation exchange membrane (Nafion) in a membrane electrode assembly. The results show that the use of smaller copper nanoparticles (25 nm) leads to a higher ethylene production (1148 μmol m-2 s-1) with a remarkable high FE (92.8%), at the same time, diminishing the competitive hydrogen evolution reaction in terms of FE. This work demonstrates the importance of nanoparticle size on reaction selectivity, which may be of help to design enhanced electrocatalytic materials for CO2 valorization to hydrocarbons.

Distinct site- and state-selective dissociation of methyl-trifluoroacetate observed in core-electron excitation at the oxygen K-edge region

Science.gov (United States)

Yamanaka, T.; Tabayashi, K.; Maruyama, T.; Harada, C.; Yoshida, H.

2009-11-01

Distinct site- and state-selective dissociation following the O1s core-excitation has been found in the gaseous molecules of methyl trifluoroacetate (MTFA). The site- and state-selective dissociation was examined by measuring the branching ratios of dominant CH3+ and CHO+ fragments. The branching ratios from MTFA showed that site-selective dissociation takes place via the excitation from the different atomic sites to the same π*CO resonance state, (O1sCO-1π*CO) and (O1sOMe-1π*CO). A pronounced O1sOMe site-selectivity was identified by a significant increment of CHO+ formation at the (O1sOMe→π*CO) band. The site-selectivity was also justified by an equivalent core approximation using the density functional theory calculation. State-selective dissociation was identified among the (O1sOMe-1π*CO), (O1sOMe-1σ*O-Me) and (O1sOMe-1σ*C-OMe) transitions originated from the same OMe core. State-selective production of CH3+ could be found at the (O1sOMe→σ*O-Me) band, whereas state-selective formation of CHO+ was observed at the (O1sOMe→π*CO) and (O1sOMe→σ*C-OMe) bands.

Potential impacts of leakage from deep CO2 geosequestration on overlying freshwater aquifers.

Science.gov (United States)

Little, Mark G; Jackson, Robert B

2010-12-01

Carbon Capture and Storage may use deep saline aquifers for CO(2) sequestration, but small CO(2) leakage could pose a risk to overlying fresh groundwater. We performed laboratory incubations of CO(2) infiltration under oxidizing conditions for >300 days on samples from four freshwater aquifers to 1) understand how CO(2) leakage affects freshwater quality; 2) develop selection criteria for deep sequestration sites based on inorganic metal contamination caused by CO(2) leaks to shallow aquifers; and 3) identify geochemical signatures for early detection criteria. After exposure to CO(2), water pH declines of 1-2 units were apparent in all aquifer samples. CO(2) caused concentrations of the alkali and alkaline earths and manganese, cobalt, nickel, and iron to increase by more than 2 orders of magnitude. Potentially dangerous uranium and barium increased throughout the entire experiment in some samples. Solid-phase metal mobility, carbonate buffering capacity, and redox state in the shallow overlying aquifers influence the impact of CO(2) leakage and should be considered when selecting deep geosequestration sites. Manganese, iron, calcium, and pH could be used as geochemical markers of a CO(2) leak, as their concentrations increase within 2 weeks of exposure to CO(2).

National radioactive waste repository site selection study. Phase 2. A report on public comment

International Nuclear Information System (INIS)

1995-11-01

Agreement was reached in principle between State/Territory and the Commonwealth of Australia Governments that a suitable site for a radioactive wastes repository must be found. The discussion papers resulting from the Phase 1 and Phase 2 of the site selection study were released for public comment. The national repository will be for disposal of low level and short-lived intermediate level radioactive wastes streaming from the medical, research and industrial use of radioisotopes in Australia. The purpose of this report is to summarise and respond in general terms to comment received on the discussion paper -Phase 2 of the study. Forty five submissions were received. Of these: 18 supported the Phase 2 study approach and the concept of a national repository; 13 did not state a clear position but either requested more information or provided constructive comment on the siting process; 7 supported the site selection approach and the repository concept but suggested that the repository should not be sited in a particular area; 3 opposed the siting of the repository in their vicinity but not necessarily the repository concept and site selection approach; 4 opposed the concept of a national repository. This compares with 124 submissions on Phase 1 of the study, of which 57 opposed the national repository concept (52 of these were from letters elicited by Greenpeace) and 48 supported the establishment of a national repository and the site selection approach proposed. 3 figs

CO2 dispersion modelling over Paris region within the CO2-MEGAPARIS project

Directory of Open Access Journals (Sweden)

C. Lac

2013-05-01

Full Text Available Accurate simulation of the spatial and temporal variability of tracer mixing ratios over urban areas is a challenging and interesting task needed to be performed in order to utilise CO2 measurements in an atmospheric inverse framework and to better estimate regional CO2 fluxes. This study investigates the ability of a high-resolution model to simulate meteorological and CO2 fields around Paris agglomeration during the March field campaign of the CO2-MEGAPARIS project. The mesoscale atmospheric model Meso-NH, running at 2 km horizontal resolution, is coupled with the Town Energy Balance (TEB urban canopy scheme and with the Interactions between Soil, Biosphere and Atmosphere CO2-reactive (ISBA-A-gs surface scheme, allowing a full interaction of CO2 modelling between the surface and the atmosphere. Statistical scores show a good representation of the urban heat island (UHI with stronger urban–rural contrasts on temperature at night than during the day by up to 7 °C. Boundary layer heights (BLH have been evaluated on urban, suburban and rural sites during the campaign, and also on a suburban site over 1 yr. The diurnal cycles of the BLH are well captured, especially the onset time of the BLH increase and its growth rate in the morning, which are essential for tall tower CO2 observatories. The main discrepancy is a small negative bias over urban and suburban sites during nighttime (respectively 45 m and 5 m, leading to a few overestimations of nocturnal CO2 mixing ratios at suburban sites and a bias of +5 ppm. The diurnal CO2 cycle is generally well captured for all the sites. At the Eiffel tower, the observed spikes of CO2 maxima occur every morning exactly at the time at which the atmospheric boundary layer (ABL growth reaches the measurement height. At suburban ground stations, CO2 measurements exhibit maxima at the beginning and at the end of each night, when the ABL is fully contracted, with a strong spatio-temporal variability. A

Effects of Force Field Selection on the Computational Ranking of MOFs for CO2 Separations.

Science.gov (United States)

Dokur, Derya; Keskin, Seda

2018-02-14

Metal-organic frameworks (MOFs) have been considered as highly promising materials for adsorption-based CO 2 separations. The number of synthesized MOFs has been increasing very rapidly. High-throughput molecular simulations are very useful to screen large numbers of MOFs in order to identify the most promising adsorbents prior to extensive experimental studies. Results of molecular simulations depend on the force field used to define the interactions between gas molecules and MOFs. Choosing the appropriate force field for MOFs is essential to make reliable predictions about the materials' performance. In this work, we performed two sets of molecular simulations using the two widely used generic force fields, Dreiding and UFF, and obtained adsorption data of CO 2 /H 2 , CO 2 /N 2 , and CO 2 /CH 4 mixtures in 100 different MOF structures. Using this adsorption data, several adsorbent evaluation metrics including selectivity, working capacity, sorbent selection parameter, and percent regenerability were computed for each MOF. MOFs were then ranked based on these evaluation metrics, and top performing materials were identified. We then examined the sensitivity of the MOF rankings to the force field type. Our results showed that although there are significant quantitative differences between some adsorbent evaluation metrics computed using different force fields, rankings of the top MOF adsorbents for CO 2 separations are generally similar: 8, 8, and 9 out of the top 10 most selective MOFs were found to be identical in the ranking for CO 2 /H 2 , CO 2 /N 2 , and CO 2 /CH 4 separations using Dreiding and UFF. We finally suggested a force field factor depending on the energy parameters of atoms present in the MOFs to quantify the robustness of the simulation results to the force field selection. This easily computable factor will be highly useful to determine whether the results are sensitive to the force field type or not prior to performing computationally demanding

Geological characterization of CO{sub 2} storage sites: lessons from Sleipner, Northern North Sea

Energy Technology Data Exchange (ETDEWEB)

R.A. Chadwick; P. Zweigel; U. Gregersen; G.A. Kirby; S. Holloway; P.N. Johannessen [British Geological Survey, Keyworth (United Kingdom). Kingsley Dunham Centre

2003-07-01

The paper aims to draw some generic conclusions on reservoir characterization based on the Sleipner operation in the North Sea where CO{sub 2} is being injected into the Utsira Sand, a saline aquifer. Regional mapping and petrophysical characterization of the reservoir, based on 2D seismic and well data, enable gross storage potential to be evaluated. Site specific injection studies, however, require precision depth mapping based on 3D seismic data and detailed knowledge of reservoir stratigraphy. Stratigraphical and structural permeability barriers, difficult to detect prior to CO{sub 2} injection, can radically affect CO{sub 2} migration within the aquifer. 5 refs., 5 figs.

Mass transfer of CO2 to groundwaters from a near-surface waste disposal site

International Nuclear Information System (INIS)

Caron, F.; Wilkinson, S.R.; Manni, G.; Torok, J.

1995-01-01

Gaseous 14 CO 2 originating from buried low-level radioactive wastes (LLRW) in a near-surface disposal site can be released to the environment via two major paths: gas-phase diffusion through soils to the atmosphere, and dissolution in groundwater, followed by aqueous migration. Aqueous migration would give the highest dose to an individual, especially if C-14 was converted to an organic form and ingested. Gaseous diffusion would give a lower dose, largely because of atmospheric dispersion and dilution. The objective of this study was to develop the capability to estimate which of the two paths will likely be dominant for typical near-surface disposal facilities. The main missing parameter for making this estimate was a mass-transfer coefficient (K L ) of 14 CO 2 to groundwaters, which was determined experimentally using a large sand box. The K L thus determined was approximately 10 to 20 times smaller than for an open liquid surface. This suggests that there is a potential resistance to mass transfer, probably caused by the capillary fringe. The value obtained was incorporated into a simple model of CO 2 transport around a typical near-surface disposal site. The model suggests that CO 2 transport via both gaseous release and aqueous migration paths are of similar magnitude for a repository located ∼2 m above the water table. (author). 11 refs., 2 tabs., 2 figs

Direct conversion of CO2 into liquid fuels with high selectivity over a bifunctional catalyst

Science.gov (United States)

Gao, Peng; Li, Shenggang; Bu, Xianni; Dang, Shanshan; Liu, Ziyu; Wang, Hui; Zhong, Liangshu; Qiu, Minghuang; Yang, Chengguang; Cai, Jun; Wei, Wei; Sun, Yuhan

2017-10-01

Although considerable progress has been made in carbon dioxide (CO2) hydrogenation to various C1 chemicals, it is still a great challenge to synthesize value-added products with two or more carbons, such as gasoline, directly from CO2 because of the extreme inertness of CO2 and a high C-C coupling barrier. Here we present a bifunctional catalyst composed of reducible indium oxides (In2O3) and zeolites that yields a high selectivity to gasoline-range hydrocarbons (78.6%) with a very low methane selectivity (1%). The oxygen vacancies on the In2O3 surfaces activate CO2 and hydrogen to form methanol, and C-C coupling subsequently occurs inside zeolite pores to produce gasoline-range hydrocarbons with a high octane number. The proximity of these two components plays a crucial role in suppressing the undesired reverse water gas shift reaction and giving a high selectivity for gasoline-range hydrocarbons. Moreover, the pellet catalyst exhibits a much better performance during an industry-relevant test, which suggests promising prospects for industrial applications.

Criteria for selecting a CO2/climate change region of study

International Nuclear Information System (INIS)

Cushman, R.; Easterling, W.; Rosenberg, N.; Malone, T.; Edmonds, J.; Scott, M.; Stoke, G.

1989-01-01

This effort has three near-term goals: (1) to develop robust methods of analysis including the analysis of uncertainty; (2) to develop information systems to support CO 2 /climate change analysis; and (3) to develop channels of communication among researchers and between researchers and parties potentially affected by CO 2 /climate change. Initially, the program will focus on a single region of the United States, employ a historical analog climate, and analyze the interactions of all of the resources resident within that region as they might evolve under current conditions and under evolving CO 2 /climate change over the next 50 years. Five elements of the program will address the issues of: Analysis, Information Systems, Uncertainty, Knowledge Transfer, and Coordination. This paper will give special attention to the analytical framework and in particular to the criteria for selecting a region for study. 19 refs., 2 figs

Segregation of O2 and CO on the surface of dust grains determines the desorption energy of O2

Science.gov (United States)

Noble, J. A.; Diana, S.; Dulieu, F.

2015-12-01

Selective depletion towards pre-stellar cores is still not understood. The exchange between the solid and gas phases is central to this mystery. The aim of this paper is to show that the thermal desorption of O2 and CO from a submonolayer mixture is greatly affected by the composition of the initial surface population. We have performed thermally programmed desorption (TPD) experiments on various submonolayer mixtures of O2 and CO. Pure O2 and CO exhibit almost the same desorption behaviour, but their desorption differs strongly when mixed. Pure O2 is slightly less volatile than CO, while in mixtures, O2 desorbs earlier than CO. We analyse our data using a desorption law linking competition for binding sites with desorption, based on the assumption that the binding energy distribution of both molecules is the same. We apply Fermi-Dirac statistics in order to calculate the adsorption site population distribution, and derive the desorbing fluxes. Despite its simplicity, the model reproduces the observed desorption profiles, indicating that competition for adsorption sites is the reason for lower temperature O2 desorption. CO molecules push-out or `dislodge' O2 molecules from the most favourable binding sites, ultimately forcing their early desorption. It is crucial to consider the surface coverage of dust grains in any description of desorption. Competition for access to binding sites results in some important discrepancies between similar kinds of molecules, such as CO and O2. This is an important phenomenon to be investigated in order to develop a better understanding of the apparently selective depletion observed in dark molecular clouds.

EPR dating CO2- sites in tooth enamel apatites by ENDOR and triple resonance

International Nuclear Information System (INIS)

Vugman, N.V.; Rigby, S.E.J.

1995-01-01

In this work we combine electron paramagnetic resonance (EPR), high-resolution electron nucleus double resonance (ENDOR) and general triple resonance (GTR) spectroscopies, to study the local environment of the CO 2 - groups created by ionizing radiation in fossil tooth enamel. We demonstrate that the CO 2 - groups occupy slightly modified phosphate sites in the hydroxyapatite lattice. In quaternary shark enamel we found these groups to be interacting with water molecules in the apatite channels. The absence of water molecules as first neighbours in mammalian samples indicate, however, that these molecules are not significantly responsible for the stabilization of CO 2 - dating centers in enamel. (author)

Selective CO Methanation on Ru/TiO2 Catalysts: Role and Influence of Metal-Support Interactions

DEFF Research Database (Denmark)

Abdel-Mageed, Ali M.; Widmann, D.; Olesen, Sine Ellemann

2015-01-01

Aiming at a detailed understanding of the role of metal-support interactions in the selective methanation of CO in CO2-rich reformate gases, we have investigated the catalytic performance of a set of Ru/TiO2 catalysts with comparable Ru loading, Ru particle size, and TiO2 phase composition but very...... different surface areas (ranging from 20 to 235 m2 g-1) in this reaction. The activity for CO methanation, under steady-state conditions, was found to strongly depend on the TiO2 support surface area, increasing first with increasing surface area up to a maximum activity for the Ru/TiO2 catalyst...... with a surface area of 121 m2 g-1 and then decreasing for an even higher surface area; however, the selectivity is mainly determined by the Ru particle size, which slightly decreases with increasing support surface area. This goes along with an increase in selectivity for CO methanation, in agreement...

Morphological and Compositional Design of Pd-Cu Bimetallic Nanocatalysts with Controllable Product Selectivity toward CO2 Electroreduction.

Science.gov (United States)

Zhu, Wenjin; Zhang, Lei; Yang, Piaoping; Chang, Xiaoxia; Dong, Hao; Li, Ang; Hu, Congling; Huang, Zhiqi; Zhao, Zhi-Jian; Gong, Jinlong

2018-02-01

Electrochemical conversion of carbon dioxide (electrochemical reduction of carbon dioxide) to value-added products is a promising way to solve CO 2 emission problems. This paper describes a facile one-pot approach to synthesize palladium-copper (Pd-Cu) bimetallic catalysts with different structures. Highly efficient performance and tunable product distributions are achieved due to a coordinative function of both enriched low-coordinated sites and composition effects. The concave rhombic dodecahedral Cu 3 Pd (CRD-Cu 3 Pd) decreases the onset potential for methane (CH 4 ) by 200 mV and shows a sevenfold CH 4 current density at -1.2 V (vs reversible hydrogen electrode) compared to Cu foil. The flower-like Pd 3 Cu (FL-Pd 3 Cu) exhibits high faradaic efficiency toward CO in a wide potential range from -0.7 to -1.3 V, and reaches a fourfold CO current density at -1.3 V compared to commercial Pd black. Tafel plots and density functional theory calculations suggest that both the introduction of high-index facets and alloying contribute to the enhanced CH 4 current of CRD-Cu 3 Pd, while the alloy effect is responsible for high CO selectivity of FL-Pd 3 Cu. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Densely Packed, Ultra Small SnO Nanoparticles for Enhanced Activity and Selectivity in Electrochemical CO2 Reduction.

Science.gov (United States)

Gu, Jun; Héroguel, Florent; Luterbacher, Jeremy; Hu, Xile

2018-03-05

Controlling the selectivity in electrochemical CO 2 reduction is an unsolved challenge. While tin (Sn) has emerged as a promising non-precious catalyst for CO 2 electroreduction, most Sn-based catalysts produce formate as the major product, which is less desirable than CO in terms of separation and further use. Tin monoxide (SnO) nanoparticles supported on carbon black were synthesized and assembled and their application in CO 2 reduction was studied. Remarkably high selectivity and partial current densities for CO formation were obtained using these SnO nanoparticles compared to other Sn catalysts. The high activity is attributed to the ultra-small size of the nanoparticles (2.6 nm), while the high selectivity is attributed to a local pH effect arising from the dense packing of nanoparticles in the conductive carbon black matrix. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Southern Adriatic sea as a potential area for CO2 geological storage

International Nuclear Information System (INIS)

Volpi, V.; Forlin, F.; Donda, F.; Civile, D.; Facchin, L.; Sauli, L.; Merson, B.; Sinza-Mendieta, K.; Shams, A.

2015-01-01

The Southern Adriatic Sea is one of the five prospective areas for CO 2 storage being evaluated under the three year (FP7) European SiteChar project dedicated to the characterization of European CO 2 storage sites. The potential reservoir for CO 2 storage is represented by a carbonate formation, the wackstones and packstones of the Scaglia Formation (Upper Cretaceous-Paleogene). In this paper, we present the geological characterization and the 3D modeling that led to the identification of three sites, named Grazia, Rovesti and Grifone, where the Scaglia Formation, with an average thickness of 50 m, reveals good petrophysical characteristics and is overlain by an up to 1 200 thick cap-rock. The vicinity of the selected sites to the Enel - Federico II power plant (one of the major Italian CO 2 emitter) where a pilot plant for CO 2 capture has been already started in April 2010, represents a good opportunity to launch the first Carbon Capture and Storage (CCS) pilot project in Italy and to apply this technology at industrial level, strongly contributing at the same time at reducing the national CO 2 emissions. (authors)

Effects of CO2 gas as leaks from geological storage sites on agro-ecosystems

International Nuclear Information System (INIS)

Patil, Ravi H.; Colls, Jeremy J.; Steven, Michael D.

2010-01-01

Carbon capture and storage in geological formations has potential risks in the long-term safety because of the possibility of CO 2 leakage. Effects of leaking gas, therefore, on vegetation, soil, and soil-inhabiting organisms are critical to understand. An artificial soil gassing and response detection field facility developed at the University of Nottingham was used to inject CO 2 gas at a controlled flow rate (1 l min -1 ) into soil to simulate build-up of soil CO 2 concentrations and surface fluxes from two land use types: pasture grassland, and fallow followed by winter bean. Mean soil CO 2 concentrations was significantly higher in gassed pasture plots than in gassed fallow plots. Germination of winter bean sown in gassed fallow plots was severely hindered and the final crop stand was reduced to half. Pasture grass showed stress symptoms and above-ground biomass was significantly reduced compared to control plot. A negative correlation (r = -0.95) between soil CO 2 and O 2 concentrations indicated that injected CO 2 displaced O 2 from soil. Gassing CO 2 reduced soil pH both in grass and fallow plots (p = 0.012). The number of earthworm castings was twice as much in gassed plots than in control plots. This study showed adverse effects of CO 2 gas on agro-ecosystem in case of leakage from storage sites to surface.

Theoretical Investigations of CO 2 and H 2 Sorption in an Interpenetrated Square-Pillared Metal–Organic Material

KAUST Repository

Pham, Tony

2013-05-16

Simulations of CO2 and H2 sorption and separation were performed in [Cu(dpa)2SiF6-i], a metal-organic material (MOM) consisting of an interpenetrated square grid of Cu2+ ions coordinated to 4,4′-dipyridylacetylene (dpa) rings and pillars of SiF6 2- ions. This class of water stable MOMs shows great promise in practical gas sorption/separation with especially high selectivity for CO2 and variable selectivity for other energy related gases. Simulated CO2 sorption isotherms and isosteric heats of adsorption, Qst, at ambient temperatures were in excellent agreement with the experimental measurements at all pressures considered. Further, it was observed that the Qst for CO2 increases as a function of uptake in [Cu(dpa)2SiF6-i]. This suggests that nascently sorbed CO2 molecules within a channel contribute to a more energetically favorable site for additional CO2 molecules, i.e., in stark contrast to typical behavior, sorbate intermolecular interactions enhance sorption energetics with increased loading. The simulated structure at CO2 saturation shows a loading with tight packing of 8 CO2 molecules per unit cell. The CO2 molecules can be seen alternating between a vertical and horizontal alignment within a channel, with each CO2 molecule coordinating to an equatorial fluorine MOM atom. Calculated H 2 sorption isotherms and Qst values were also in good agreement with the experimental measurements in [Cu(dpa)2SiF 6-i]. H2 saturation corresponds to 10 H2 molecules per unit cell for the studied structure. Moreover, there were two observed binding sites for hydrogen sorption in [Cu(dpa)2SiF 6-i]. Simulations of a 30:70 CO2/H2 mixture, typical of syngas, in [Cu(dpa)2SiF6-i] showed that the MOM exhibited a high uptake and selectivity for CO2. In addition, it was observed that the presence of H2O had a negligible effect on the CO2 uptake and selectivity in [Cu(dpa)2SiF6-i], as simulations of a mixture containing CO2, H2, and small amounts of CO, N2, and H2O produced comparable

Assessment of Ademe's R and D actions for the CO2 capture and storage sector

International Nuclear Information System (INIS)

2015-05-01

This publication presents research actions and projects supported by the ADEME in the field of CO 2 capture and storage. This programme aims at promoting the emergence of significant innovations, at developing the national technology portfolio, at identifying and reducing uncertainties related to exploitation, and at developing and strengthening its technological integration in manufacturing industry and energy sectors. While indicating the invested amount, research demonstrator projects are mentioned. Results obtained between 2007 and 2013 in different fields are briefly described: technical-economic studies or pre-feasibility studies, CO 2 capture (capture in post-combustion or in oxy-combustion), CO 2 geological storage (site selection, knowledge development on storage site sustainability, safety of CO 2 storage sites, monitoring of CO 2 storage sites, environmental impacts of storage sites), and issue of social feasibility of CO 2 capture and storage

The role of safety analyses in site selection. Some personal observations based on the experience from the Swiss site selection process

Energy Technology Data Exchange (ETDEWEB)

Zuidema, Piet [Nagra, Wettingen (Switzerland)

2015-07-01

In Switzerland, the site selection process according to the ''Sectoral Plan for Deep Geological Repositories'' (BFE 2008) is underway since 2008. This process takes place in three stages. In stage 1 geological siting regions (six for the L/ILW repository and three for the HLW repository) have been identified, in stage 2 sites for the surface facilities have been identified for all siting regions in close co-operation with the sting regions and a narrowing down of the number of siting regions based on geological criteria will take place. In stage 3 the sites for a general license application are selected and the general license applications will be submitted which eventually will lead to the siting decision for both repository types. In the Swiss site selection process, safety has the highest priority. Many factors affect safety and thus a whole range of safety-related issues are considered in the identification and screening of siting possibilities. Besides dose calculations a range of quantitative and qualitative issues are considered. Dose calculations are performed in all three stages of the site selection process. In stage 1 generic safety calculations were made to develop criteria to be used for the identification of potential siting regions. In stage 2, dose calculations are made for comparing the different siting regions according to a procedure prescribed in detail by the regulator. Combined with qualitative evaluations this will lead to a narrowing down of the number of siting regions to at least two siting regions for each repository type. In stage 3 full safety cases will be prepared as part of the documentation for the general license applications. Besides the dose calculations, many other issues related to safety are analyzed in a quantitative and qualitative manner. These consider the 13 criteria defined in the Sectoral Plan and the corresponding indicators. The features analyzed cover the following broad themes: efficiency of

The role of safety analyses in site selection. Some personal observations based on the experience from the Swiss site selection process

International Nuclear Information System (INIS)

Zuidema, Piet

2015-01-01

In Switzerland, the site selection process according to the ''Sectoral Plan for Deep Geological Repositories'' (BFE 2008) is underway since 2008. This process takes place in three stages. In stage 1 geological siting regions (six for the L/ILW repository and three for the HLW repository) have been identified, in stage 2 sites for the surface facilities have been identified for all siting regions in close co-operation with the sting regions and a narrowing down of the number of siting regions based on geological criteria will take place. In stage 3 the sites for a general license application are selected and the general license applications will be submitted which eventually will lead to the siting decision for both repository types. In the Swiss site selection process, safety has the highest priority. Many factors affect safety and thus a whole range of safety-related issues are considered in the identification and screening of siting possibilities. Besides dose calculations a range of quantitative and qualitative issues are considered. Dose calculations are performed in all three stages of the site selection process. In stage 1 generic safety calculations were made to develop criteria to be used for the identification of potential siting regions. In stage 2, dose calculations are made for comparing the different siting regions according to a procedure prescribed in detail by the regulator. Combined with qualitative evaluations this will lead to a narrowing down of the number of siting regions to at least two siting regions for each repository type. In stage 3 full safety cases will be prepared as part of the documentation for the general license applications. Besides the dose calculations, many other issues related to safety are analyzed in a quantitative and qualitative manner. These consider the 13 criteria defined in the Sectoral Plan and the corresponding indicators. The features analyzed cover the following broad themes: efficiency of

Non-sensitized selective photochemical reduction of CO2 to CO under visible light with an iron molecular catalyst.

Science.gov (United States)

Rao, Heng; Bonin, Julien; Robert, Marc

2017-03-02

A substituted tetraphenyl iron porphyrin, bearing positively charged trimethylammonio groups at the para position of each phenyl ring, demonstrates its ability as a homogeneous molecular catalyst to selectively reduce CO 2 to CO under visible light irradiation in organic media without the assistance of a sensitizer and no competitive hydrogen evolution for several days.

Inverse Modeling of Water-Rock-CO2 Batch Experiments: Potential Impacts on Groundwater Resources at Carbon Sequestration Sites.

Science.gov (United States)

Yang, Changbing; Dai, Zhenxue; Romanak, Katherine D; Hovorka, Susan D; Treviño, Ramón H

2014-01-01

This study developed a multicomponent geochemical model to interpret responses of water chemistry to introduction of CO2 into six water-rock batches with sedimentary samples collected from representative potable aquifers in the Gulf Coast area. The model simulated CO2 dissolution in groundwater, aqueous complexation, mineral reactions (dissolution/precipitation), and surface complexation on clay mineral surfaces. An inverse method was used to estimate mineral surface area, the key parameter for describing kinetic mineral reactions. Modeling results suggested that reductions in groundwater pH were more significant in the carbonate-poor aquifers than in the carbonate-rich aquifers, resulting in potential groundwater acidification. Modeled concentrations of major ions showed overall increasing trends, depending on mineralogy of the sediments, especially carbonate content. The geochemical model confirmed that mobilization of trace metals was caused likely by mineral dissolution and surface complexation on clay mineral surfaces. Although dissolved inorganic carbon and pH may be used as indicative parameters in potable aquifers, selection of geochemical parameters for CO2 leakage detection is site-specific and a stepwise procedure may be followed. A combined study of the geochemical models with the laboratory batch experiments improves our understanding of the mechanisms that dominate responses of water chemistry to CO2 leakage and also provides a frame of reference for designing monitoring strategy in potable aquifers.

Site selection handbook: Workshop on site selection for low-level radioactive waste disposal facilities

International Nuclear Information System (INIS)

1987-10-01

The Low-Level Radioactive Waste Policy Amendments Act of 1985 (LLRWPAA) requires the Department of Energy (DOE) to provide technical assistance to ''...those compact regions, host States and nonmember States determined by the Secretary to require assistance.'' Technical assistance has been defined to include, but not be limited to, ''technical guidelines for site selection.'' This site selection workshop was developed to assist States and Compacts in developing new low-level radioactive waste (LLW) disposal sites in accordance with the requirements of the LLRWPAA. The workshop comprises a series of lectures, discussion topics, and exercises, supported by this Site Selection Workshop Handbook, designed to examine various aspects of a comprehensive site selection program. It is not an exhaustive treatment of all aspects of site selection, nor is it prescriptive. The workshop focuses on the major elements of site selection and the tools that can be used to implement the site selection program

The impact of CO2 emissions on economic growth: evidence from selected higher CO2 emissions economies.

Science.gov (United States)

Azam, Muhammad; Khan, Abdul Qayyum; Bin Abdullah, Hussin; Qureshi, Muhammad Ejaz

2016-04-01

The main purpose of this work is to analyze the impact of environmental degradation proxied by CO2 emissions per capita along with some other explanatory variables namely energy use, trade, and human capital on economic growth in selected higher CO2 emissions economies namely China, the USA, India, and Japan. For empirical analysis, annual data over the period spanning between 1971 and 2013 are used. After using relevant and suitable tests for checking data properties, the panel fully modified ordinary least squares (FMOLS) method is employed as an analytical technique for parameter estimation. The panel group FMOLS results reveal that almost all variables are statistically significant, whereby test rejects the null hypotheses of non cointegration, demonstrating that all variables play an important role in affecting the economic growth role across countries. Where two regressors namely CO2 emissions and energy use show significantly negative impacts on economic growth, for trade and human capital, they tend to show the significantly positive impact on economic growth. However, for the individual analysis across countries, the panel estimate suggests that CO2 emissions have a significant positive relationship with economic growth for China, Japan, and the USA, while it is found significantly negative in case of India. The empirical findings of the study suggest that appropriate and prudent policies are required in order to control pollution emerging from areas other than liquefied fuel consumption. The ultimate impact of shrinking pollution will help in supporting sustainable economic growth and maturation as well as largely improve society welfare.

Regional variability of grassland CO2 fluxes in Tyrol/Austria

Science.gov (United States)

Irschick, Christoph; Hammerle, Albin; Haslwanter, Alois; Wohlfahrt, Georg

2010-05-01

The FLUXNET project [1] aims at quantifying the magnitude and controls on the CO2, H2O and energy exchange of terrestrial ecosystems. Ideally, the various biomes of the Earth would be sampled in proportion to their spatial extent - in reality, however, study site selection is usually based on other (more practical) criteria so that a bias exists towards certain biomes and ecosystem types. This may be problematic because FLUXNET data are used to calibrate/parameterize models at various scales - if certain ecosystems are poorly replicated this may bias model predictions. Here we present data from a project in Tyrol/Austria where we have been investigating the CO2, H2O and energy exchange of five grassland sites during 2005-2007. The five permanent grassland sites were exposed to similar climate, but differed slightly in management. In a FLUXNET style approach, any of these sites might have been selected for making long-term flux measurements - the aim of this project was to examine the representativeness of these sites and, if evident, elucidate the causes for and controls on differences between sites. To this end we conducted continuous eddy covariance flux measurements at one (anchor) site [2, 3], and episodic, month long flux measurements at the four additional sites using a roving eddy covariance tower. These data were complemented by measurements of environmental drivers, the amount of above ground phytomass and basic data on vegetation and soil type, as well as management. Data are subject to a rigorous statistical analysis in order to quantify significant differences in the CO2, H2O and energy exchange between the sites and to identify the factors which are responsible for these differences. In the present contribution we report results on CO2 fluxes. Our major findings are that (i) site-identity of the surveyed grassland ecosystems was a significant factor for the net ecosystem CO2 exchange (NEE), somewhat less for gross primary production (GPP) and not for

The site selection process

International Nuclear Information System (INIS)

Kittel, J.H.

1989-01-01

One of the most arduous tasks associated with the management of radioactive wastes is the siting of new disposal facilities. Experience has shown that the performance of the disposal facility during and after disposal operations is critically dependent on the characteristics of the site itself. The site selection process consists of defining needs and objectives, identifying geographic regions of interest, screening and selecting candidate sites, collecting data on the candidate sites, and finally selecting the preferred site. Before the site selection procedures can be implemented, however, a formal legal system must be in place that defines broad objectives and, most importantly, clearly establishes responsibilities and accompanying authorities for the decision-making steps in the procedure. Site selection authorities should make every effort to develop trust and credibility with the public, local officials, and the news media. The responsibilities of supporting agencies must also be spelled out. Finally, a stable funding arrangement must be established so that activities such as data collection can proceed without interruption. Several examples, both international and within the US, are given

Re-assessment of plant carbon dynamics at the Duke free-air CO2 enrichment site: interactions of atmospheric [CO2] with nitrogen and water availability over stand development

Science.gov (United States)

Heather R. McCarthy; Ram Oren; Kurt H Johnsen; Anne Gallet-Budynek; Seth G. Pritchard; Charles W Cook; Shannon L. LaDeau; Robert B. Jackson; Adrien C. Finzi

2010-01-01

The potential for elevated [CO2]-induced changes to plant carbon (C) storage, through modifications in plant production and allocation of C among plant pools, is an important source of uncertainty when predicting future forest function. Utilizing 10 yr of data from the Duke free-air CO2 enrichment site, we evaluated the...

Adaptive selection of diurnal minimum variation: a statistical strategy to obtain representative atmospheric CO2 data and its application to European elevated mountain stations

Directory of Open Access Journals (Sweden)

Y. Yuan

2018-03-01

Full Text Available Critical data selection is essential for determining representative baseline levels of atmospheric trace gases even at remote measurement sites. Different data selection techniques have been used around the world, which could potentially lead to reduced compatibility when comparing data from different stations. This paper presents a novel statistical data selection method named adaptive diurnal minimum variation selection (ADVS based on CO2 diurnal patterns typically occurring at elevated mountain stations. Its capability and applicability were studied on records of atmospheric CO2 observations at six Global Atmosphere Watch stations in Europe, namely, Zugspitze-Schneefernerhaus (Germany, Sonnblick (Austria, Jungfraujoch (Switzerland, Izaña (Spain, Schauinsland (Germany, and Hohenpeissenberg (Germany. Three other frequently applied statistical data selection methods were included for comparison. Among the studied methods, our ADVS method resulted in a lower fraction of data selected as a baseline with lower maxima during winter and higher minima during summer in the selected data. The measured time series were analyzed for long-term trends and seasonality by a seasonal-trend decomposition technique. In contrast to unselected data, mean annual growth rates of all selected datasets were not significantly different among the sites, except for the data recorded at Schauinsland. However, clear differences were found in the annual amplitudes as well as the seasonal time structure. Based on a pairwise analysis of correlations between stations on the seasonal-trend decomposed components by statistical data selection, we conclude that the baseline identified by the ADVS method is a better representation of lower free tropospheric (LFT conditions than baselines identified by the other methods.

Adaptive selection of diurnal minimum variation: a statistical strategy to obtain representative atmospheric CO2 data and its application to European elevated mountain stations

Science.gov (United States)

Yuan, Ye; Ries, Ludwig; Petermeier, Hannes; Steinbacher, Martin; Gómez-Peláez, Angel J.; Leuenberger, Markus C.; Schumacher, Marcus; Trickl, Thomas; Couret, Cedric; Meinhardt, Frank; Menzel, Annette

2018-03-01

Critical data selection is essential for determining representative baseline levels of atmospheric trace gases even at remote measurement sites. Different data selection techniques have been used around the world, which could potentially lead to reduced compatibility when comparing data from different stations. This paper presents a novel statistical data selection method named adaptive diurnal minimum variation selection (ADVS) based on CO2 diurnal patterns typically occurring at elevated mountain stations. Its capability and applicability were studied on records of atmospheric CO2 observations at six Global Atmosphere Watch stations in Europe, namely, Zugspitze-Schneefernerhaus (Germany), Sonnblick (Austria), Jungfraujoch (Switzerland), Izaña (Spain), Schauinsland (Germany), and Hohenpeissenberg (Germany). Three other frequently applied statistical data selection methods were included for comparison. Among the studied methods, our ADVS method resulted in a lower fraction of data selected as a baseline with lower maxima during winter and higher minima during summer in the selected data. The measured time series were analyzed for long-term trends and seasonality by a seasonal-trend decomposition technique. In contrast to unselected data, mean annual growth rates of all selected datasets were not significantly different among the sites, except for the data recorded at Schauinsland. However, clear differences were found in the annual amplitudes as well as the seasonal time structure. Based on a pairwise analysis of correlations between stations on the seasonal-trend decomposed components by statistical data selection, we conclude that the baseline identified by the ADVS method is a better representation of lower free tropospheric (LFT) conditions than baselines identified by the other methods.

Porous carbon derived via KOH activation of a hypercrosslinked porous organic polymer for efficient CO{sub 2}, CH{sub 4}, H{sub 2} adsorptions and high CO{sub 2}/N{sub 2} selectivity

Energy Technology Data Exchange (ETDEWEB)

Modak, Arindam; Bhaumik, Asim, E-mail: msab@iacs.res.in

2015-12-15

Microporous carbon having Brunauer-Emmett-Teller (BET) surface area of 2186 m{sup 2} g{sup −1} and micropore volume of 0.85 cm{sup 3} g{sup −1} has been synthesized via KOH induced high temperature carbonization of a non-conjugated hypercrosslinked organic polymer. Owing to the templating and activation by KOH, we have succeeded in making a microporous carbon from this porous polymer and the resultant carbon material showed high uptake for CO{sub 2} (7.6 mmol g{sup −1}) and CH{sub 4} (2.4 mmol g{sup −1}) at 1 atm, 273 K together with very good selectivity for the CO{sub 2}/N{sub 2} (30.2) separation. Furthermore, low pressure (1 atm) H{sub 2} (2.6 wt%, 77 K) and water uptake (57.4 wt%, 298 K) ability of this polymer derived porous activated carbon is noteworthy. - Graphical abstract: Microporous carbon with BET surface area of 2186 m{sup 2} g{sup −1} has been synthesized via KOH activation of a porous organic polymer and it showed high uptake for CO{sub 2} (7.6 mmol g{sup −1}), CH{sub 4} (2.4 mmol g{sup −1}) and H{sub 2} (2.6 wt%) at 1 atm together with very good selectivity for CO{sub 2}. - Highlights: • Porous carbon from hypercrosslinked organic polymer. • KOH activated carbon with BET surface area 2186 m{sup 2} g{sup −1}. • High CO2 uptake (7.6 mmol g{sup −1}) and CO{sub 2}/N{sub 2} selectivity (30.2). • Porous carbon also showed high H{sub 2} (2.6 wt%) and H{sub 2}O (57.4 wt%) uptakes.

CO2 Separation and Capture Properties of Porous Carbonaceous Materials from Leather Residues

Directory of Open Access Journals (Sweden)

Ana Arenillas

2013-10-01

Full Text Available Carbonaceous porous materials derived from leather skin residues have been found to have excellent CO2 adsorption properties, with interestingly high gas selectivities for CO2 (α > 200 at a gas composition of 15% CO2/85% N2, 273K, 1 bar and capacities (>2 mmol·g−1 at 273 K. Both CO2 isotherms and the high heat of adsorption pointed to the presence of strong binding sites for CO2 which may be correlated with both: N content in the leather residues and ultrasmall pore sizes.

CO2 Separation and Capture Properties of Porous Carbonaceous Materials from Leather Residues

Science.gov (United States)

Bermúdez, José M.; Dominguez, Pablo Haro; Arenillas, Ana; Cot, Jaume; Weber, Jens; Luque, Rafael

2013-01-01

Carbonaceous porous materials derived from leather skin residues have been found to have excellent CO2 adsorption properties, with interestingly high gas selectivities for CO2 (α > 200 at a gas composition of 15% CO2/85% N2, 273K, 1 bar) and capacities (>2 mmol·g−1 at 273 K). Both CO2 isotherms and the high heat of adsorption pointed to the presence of strong binding sites for CO2 which may be correlated with both: N content in the leather residues and ultrasmall pore sizes. PMID:28788352

In situ IR studies of Co and Ce doped Mn/TiO{sub 2} catalyst for low-temperature selective catalytic reduction of NO with NH{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Qiu, Lu; Pang, Dandan; Zhang, Changliang; Meng, Jiaojiao; Zhu, Rongshu; Ouyang, Feng, E-mail: ouyangfh@hit.edu.cn

2015-12-01

Highlights: • A SCR mechanistic pathway over Mn–Co–Ce/TiO{sub 2} is proposed. • The cobalt oxide produces lots of Brønsted acid sites, which favor to the adsorption of coordinated NH{sub 3} through NH{sub 3} migration. • Ce addition improves amide ions formation to reach best NO reduction selectivity. • At low-temperature coordinated NH{sub 3} reacts with NO{sub 2}{sup −}, or amide reacts with NO (ad) or NO (g) to form N{sub 2}. At high temperature, the reaction also occurs between coordinated NH{sub 3} and nitrate species. - Abstract: The Mn–Co–Ce/TiO{sub 2} catalyst was prepared by wet co-impregnation method for selective catalytic reduction of NO by NH{sub 3} in the presence of oxygen. The adsorption and co-adsorption of NH{sub 3}, NO and O{sub 2} on catalysts were investigated by in situ FTIR spectroscopy. The results suggested that addition of cobalt and cerium oxides increased the numbers of acid and redox sites. Especially, the cobalt oxide produced lots of Brønsted acid sites, which favor to the adsorption of coordinated NH{sub 3} through NH{sub 3} migration. Ce addition improved amide ions formation to reach best NO reduction selectivity. A mechanistic pathway over Mn–Co–Ce/TiO{sub 2} was proposed. At low-temperature SCR reaction, coordinated NH{sub 3} reacted with NO{sub 2}{sup −}, and amide reacted with NO (ad) or NO (g) to form N{sub 2}. NO{sub 2} was related to the formation of nitrite on Co-contained catalysts and the generation of −NH{sub 2}{sup −} on Ce-contained catalysts. At high temperature, the other branch reaction also occurred between the coordinated NH{sub 3} and nitrate species, resulting in N{sub 2}O yield increase.

Selected Issues on CO2 in Compression Systems

Energy Technology Data Exchange (ETDEWEB)

Aarlien, R.

2004-05-15

Carbon Dioxide (CO2) has shown promising results as an alternative working fluid compared to the CFCs, HFCs and HCFCs. CO2 provides an environmental friendly alternative in a number of heat pump applications, in automobile air conditioning, and as a secondary fluid in refrigeration systems. The physical and the thermodynamic properties of CO2 differ considerably from the more conventional working fluids and offer new possibilities as well as design challenges for systems and components. On this background IEA Heat Pump Programme's Annex 27 was established. The main objective of the Annex has been to bring the CO2 heat pump technology closer to commercialization, by addressing critical issues of both basic and applied character. The scope of the work under this Annex includes compression heat pump, refrigeration and air-conditioning systems and components, with the main emphasis on heat pumps, using CO2 as working fluid. The term 'compression heat pump' covers vapor compression circuits with phase change. The term 'system' includes all the components used in a heating/cooling system from the heat pump to the inside unit, controls included. Results from 12 different research projects together with an extensive literature survey are presented. The projects are carried out as independent research projects, and the findings and the results are the sole responsibility of the authors. The following projects are presented: 1) Feasibility of transcritical CO2 systems for mobile space conditioning applications. 2) Use of CO2- and propane thermosyphons in combination with compact cooler in domestic freeze. 3) Heat transfer of carbon dioxide in an evaporator. 4) Correlating the heat transfer coefficient during in-tube cooling of turbulent supercritical CO2. 5) Heat transfer and pressure drop characteristics of super-critical CO2 in microchannel tubes under cooling. 6) Flow vaporization of CO2 in microchannel tubes. 7) Two-phase flow patterns during

Gold Nanoparticles on Polymer-Wrapped Carbon Nanotubes: An Efficient and Selective Catalyst for the Electroreduction of CO2.

Science.gov (United States)

Jhong, Huei-Ru Molly; Tornow, Claire E; Kim, Chaerin; Verma, Sumit; Oberst, Justin L; Anderson, Paul S; Gewirth, Andrew A; Fujigaya, Tsuyohiko; Nakashima, Naotoshi; Kenis, Paul J A

2017-11-17

Multiple approaches will be needed to reduce the atmospheric CO 2 levels, which have been linked to the undesirable effects of global climate change. The electroreduction of CO 2 driven by renewable energy is one approach to reduce CO 2 emissions while producing chemical building blocks, but current electrocatalysts exhibit low activity and selectivity. Here, we report the structural and electrochemical characterization of a promising catalyst for the electroreduction of CO 2 to CO: Au nanoparticles supported on polymer-wrapped multiwall carbon nanotubes. This catalyst exhibits high selectivity for CO over H 2 : 80-92 % CO, as well as high activity: partial current density for CO as high as 160 mA cm -2 . The observed high activity, originating from a high electrochemically active surface area (23 m 2  g -1 Au), in combination with the low loading (0.17 mg cm -2 ) of the highly dispersed Au nanoparticles underscores the promise of this catalyst for efficient electroreduction of CO 2 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Norwegian fjords as potential sites for CO{sub 2} experiments. A preliminary feasibility study

Energy Technology Data Exchange (ETDEWEB)

Golmen, Lars G.; Soerensen, Jan; Haugan, Peter; Bakke, Torgeir; Bjerknes, Vilhelm

1997-12-31

Large-scale deposition of CO{sub 2} will probably take place deep in the open oceans. But small-scale experiments on plume dynamics and chemical or biological impacts are more conveniently performed in Norwegian fjords. This report describes a feasibility study treating the physical, biological and legal constraints upon such experiments. Several small and large fjord basins with depths exceeding 500 m exist in western Norway. The report gives guidelines to what further steps should be taken to establish an in-situ CO{sub 2} experiment in a fjord. Twenty-six different basins have been identified in terms of maximum depths, municipal adherence etc. Deep water hydrographic conditions vary relatively little from one fjord to another. Data on the dynamical states and on deep water biology are in general lacking and a baseline study on selected fjords should be performed prior to the final selection. User conflicts and legal aspects must be considered and a complete EIA study will probably be required before any CO{sub 2} experiment can be started in a fjord. 60 refs., 13 figs.

Formation of nanoscale networks: selectively swelling amphiphilic block copolymers with CO2-expanded liquids.

Science.gov (United States)

Gong, Jianliang; Zhang, Aijuan; Bai, Hua; Zhang, Qingkun; Du, Can; Li, Lei; Hong, Yanzhen; Li, Jun

2013-02-07

Polymeric films with nanoscale networks were prepared by selectively swelling an amphiphilic diblock copolymer, polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP), with the CO(2)-expanded liquid (CXL), CO(2)-methanol. The phase behavior of the CO(2)-methanol system was investigated by both theoretical calculation and experiments, revealing that methanol can be expanded by CO(2), forming homogeneous CXL under the experimental conditions. When treated with the CO(2)-methanol system, the spin cast compact PS-b-P4VP film was transformed into a network with interconnected pores, in a pressure range of 12-20 MPa and a temperature range of 45-60 °C. The formation mechanism of the network, involving plasticization of PS and selective swelling of P4VP, was proposed. Because the diblock copolymer diffusion process is controlled by the activated hopping of individual block copolymer chains with the thermodynamic barrier for moving PVP segments from one to another, the formation of the network structures is achieved in a short time scale and shows "thermodynamically restricted" character. Furthermore, the resulting polymer networks were employed as templates, for the preparation of polypyrrole networks, by an electrochemical polymerization process. The prepared porous polypyrrole film was used to fabricate a chemoresistor-type gas sensor which showed high sensitivity towards ammonia.

Ni–Sn-Supported ZrO2 Catalysts Modified by Indium for Selective CO2 Hydrogenation to Methanol

KAUST Repository

Hengne, Amol Mahalingappa

2018-04-02

Ni and NiSn supported on zirconia (ZrO2) and on indium (In)-incorporated zirconia (InZrO2) catalysts were prepared by a wet chemical reduction route and tested for hydrogenation of CO2 to methanol in a fixed-bed isothermal flow reactor at 250 °C. The mono-metallic Ni (5%Ni/ZrO2) catalysts showed a very high selectivity for methane (99%) during CO2 hydrogenation. Introduction of Sn to this material with the following formulation 5Ni5Sn/ZrO2 (5% Ni-5% Sn/ZrO2) showed the rate of methanol formation to be 0.0417 μmol/(gcat·s) with 54% selectivity. Furthermore, the combination NiSn supported on InZrO2 (5Ni5Sn/10InZrO2) exhibited a rate of methanol formation 10 times higher than that on 5Ni/ZrO2 (0.1043 μmol/(gcat·s)) with 99% selectivity for methanol. All of these catalysts were characterized by X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy, CO2-temperature-programmed desorption, and density functional theory (DFT) studies. Addition of Sn to Ni catalysts resulted in the formation of a NiSn alloy. The NiSn alloy particle size was kept in the range of 10–15 nm, which was evidenced by HRTEM study. DFT analysis was carried out to identify the surface composition as well as the structural location of each element on the surface in three compositions investigated, namely, Ni28Sn27, Ni18Sn37, and Ni37Sn18 bimetallic nanoclusters, and results were in agreement with the STEM and electron energy-loss spectroscopy results. Also, the introduction of “Sn” and “In” helped improve the reducibility of Ni oxide and the basic strength of catalysts. Considerable details of the catalytic and structural properties of the Ni, NiSn, and NiSnIn catalyst systems were elucidated. These observations were decisive for achieving a highly efficient formation rate of methanol via CO2 by the H2 reduction process with high methanol selectivity.

Metal-Doped Nitrogenated Carbon as an Efficient Catalyst for Direct CO2 Electroreduction to CO and Hydrocarbons.

Science.gov (United States)

Varela, Ana Sofia; Ranjbar Sahraie, Nastaran; Steinberg, Julian; Ju, Wen; Oh, Hyung-Suk; Strasser, Peter

2015-09-07

This study explores the kinetics, mechanism, and active sites of the CO2 electroreduction reaction (CO2RR) to syngas and hydrocarbons on a class of functionalized solid carbon-based catalysts. Commercial carbon blacks were functionalized with nitrogen and Fe and/or Mn ions using pyrolysis and acid leaching. The resulting solid powder catalysts were found to be active and highly CO selective electrocatalysts in the electroreduction of CO2 to CO/H2 mixtures outperforming a low-area polycrystalline gold benchmark. Unspecific with respect to the nature of the metal, CO production is believed to occur on nitrogen functionalities in competition with hydrogen evolution. Evidence is provided that sufficiently strong interaction between CO and the metal enables the protonation of CO and the formation of hydrocarbons. Our results highlight a promising new class of low-cost, abundant electrocatalysts for synthetic fuel production from CO2 . © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Site specific information in site selection

International Nuclear Information System (INIS)

Aeikaes, T.; Hautojaervi, A.

1998-01-01

The programme for the siting of a deep repository for final disposal of spent nuclear fuel was started already in 1983 and is carried out today by Posiva Oy which continues the work started by Teollisuuden Voima Oy. The programme aims at site selection by the end of the year 2000. The programme has progressed in successive interim stages with defined goals. After an early phase for site identification, five sites were selected in 1987 for preliminary site characterisation. Three of these were selected and judged to be best suited for the more detailed characterisation in 1992. An additional new site was included into the programme based on a separate feasibility study in the beginning of 1997. Since the year 1983 several safety assessments together with technical plans of the facility have been completed. When approaching the site selection the needs for more detailed consideration of the site specific properties in the safety assessment have been increased. The Finnish regulator STUK has published a proposal for general safety requirements for the final disposal of spent nuclear fuel in Finland. This set of requirements has been projected to be used in conjunction of the decision making by the end 2000. Based on the site evaluation all sites can provide a stable environment and there is evidence that the requirements for the longevity of the canister can be fulfilled at each site. In this manner the four candidate sites do not differ too much from each other. The main difference between the sites is in the salinity of the deep groundwater. The significance of differences in the salinity for the long-term safety cannot be defined yet. The differences may contribute to the discussion of the longevity of the bentonite buffer and also to the modelling of the groundwater flow and transport. The use of the geosphere as a transport barrier is basically culminated on the questions about sparse but fast flow routes and 'how bad channeling can be'. To answer these questions

Site selection

CERN Multimedia

CERN PhotoLab

1968-01-01

To help resolve the problem of site selection for the proposed 300 GeV machine, the Council selected "three wise men" (left to right, J H Bannier of the Netherlands, A Chavanne of Switzerland and L K Boggild of Denmark).

Isoreticular rare earth fcu-MOFs for the selective removal of H 2 S from CO 2 containing gases

KAUST Repository

Bhatt, Prashant

2017-05-04

In this work, we present the implementation of reticular chemistry and the molecular building block approach to unveil the appropriateness of Rare Earth (RE) based Metal-Organic Frameworks (MOFs) with fcu topology for H2S removal applications. Markedly, RE-fcu-MOFs, having different pore apertures sizes in the range of 4.7-6.0 Å and different functionalities, showed excellent properties for the removal of H2S from CO2 and CH4 containing gases such as natural gas, biogas and landfill gas. A series of cyclic mixed gas breakthrough experiments were carried out on three isoreticular fcu-MOFs, containing linkers of different lengths (between 8.4 and 5 Å), by using simulated natural gas mixture containing CO2/H2S/CH4 (5%/5%/90%) under different adsorption and regeneration conditions. The fcu-MOF platform has good H2S removal capacity with a high H2S/CO2 selectivity, outperforming benchmark materials like activated carbon and Zeolites in many aspects. The comparison of H2S removal performance with the related structures of the RE-fcu-MOFs provides insightful information to shed light on the relationship between the structural features of the MOF and its associated H2S separation properties. The excellent H2S/CO2 and H2S/CH4 selectivity of these materials offer great prospective for the production of pure H2S, with acceptable levels of CO2for Claus process to produce elemental sulfur.

TG-FTIR measurement of CO2-H2O co-adsorption for CO2 air capture sorbent screening

NARCIS (Netherlands)

Smal, I.M.; Yu, Qian; Veneman, Rens; Fränzel-Luiten, B.; Brilman, Derk Willem Frederik

2014-01-01

Capturing atmospheric CO2 using solid sorbents is gaining interest. As ambient air normally contains much more (up to 100 times) water than CO2, a selective sorbent is desirable as co-adsorption will most likely occur. In this study, a convenient method based on an TG-FTIR analysis system is

Ground deformation monitoring using RADARSAT-2 DInSAR-MSBAS at the Aquistore CO2 storage site in Saskatchewan (Canada)

OpenAIRE

Czarnogorska, M.; Samsonov, S.; White, D.

2014-01-01

The research objectives of the Aquistore CO2 storage project are to design, adapt, and test non-seismic monitoring methods for measurement, and verification of CO2 storage, and to integrate data to determine subsurface fluid distributions, pressure changes and associated surface deformation. Aquistore site is located near Estevan in Southern Saskatchewan on the South flank of the Souris River and west of the Boundary Dam Power Station and the historical part of Estevan coal mine in s...

Magnetic and Moessbauer studies on GdCo3B2 and DyCo3B2

International Nuclear Information System (INIS)

Malik, S.K.; Umarji, A.M.; Shenoy, G.K.

1984-10-01

Magnetization and Moessbauer studies have been carried out on GdCo 3 B 2 and DyCo 3 B 2 . These compounds are magnetically ordered with Curie temperatures of 56 0 and 21 0 K respectively. The Co atoms are either nonmagnetic or carry a small moment in these compounds. The saturation moment of DyCo 3 B 2 at 5 0 K is smaller than the Dy 3+ free-ion value. From 161 Dy Moessbauer studies, the measured hyperfine magnetic field at the Dy site is also observed to be smaller than the free-ion value. 155 Gd Moessbauer measurements in GdCo 3 B 2 reveal the presence of large crystalline electric fields at the rare earth site. This causes the moment and the hyperfine field at the Dy site in DyCo 3 B 2 to be reduced from its free-ion value

Factors affecting CO2 emission from the power sector of selected countries in Asia and the Pacific

International Nuclear Information System (INIS)

Shrestha, Ram M.; Anandarajah, Gabrial; Liyanage, Migara H.

2009-01-01

This study analyzes the key factors behind the CO 2 emissions from the power sector in fifteen selected countries in Asia and the Pacific using the Log-Mean Divisia Index method of decomposition. The roles of changes in economic output, electricity intensity of the economy, fuel intensity of power generation and generation structure are examined in the evolution of CO 2 emission from the power sector of the selected countries during 1980-2004. The study shows that the economic growth was the dominant factor behind the increase in CO 2 emission in ten of the selected countries (i.e., Australia, China, India, Japan, Malaysia, Pakistan, South Korea, Singapore, Thailand and Vietnam, while the increasing electricity intensity of the economy was the main factor in three countries (Bangladesh, Indonesia and Philippines). Structural changes in power generation were found to be the main contributor to changes in the CO 2 emission in the case of Sri Lanka and New Zealand.

Natural analogue study of CO2 storage monitoring using probability statistics of CO2-rich groundwater chemistry

Science.gov (United States)

Kim, K. K.; Hamm, S. Y.; Kim, S. O.; Yun, S. T.

2016-12-01

For confronting global climate change, carbon capture and storage (CCS) is one of several very useful strategies as using capture of greenhouse gases like CO2 spewed from stacks and then isolation of the gases in underground geologic storage. CO2-rich groundwater could be produced by CO2 dissolution into fresh groundwater around a CO2 storage site. As consequence, natural analogue studies related to geologic storage provide insights into future geologic CO2 storage sites as well as can provide crucial information on the safety and security of geologic sequestration, the long-term impact of CO2 storage on the environment, and field operation and monitoring that could be implemented for geologic sequestration. In this study, we developed CO2 leakage monitoring method using probability density function (PDF) by characterizing naturally occurring CO2-rich groundwater. For the study, we used existing data of CO2-rich groundwaters in different geological regions (Gangwondo, Gyeongsangdo, and Choongchungdo provinces) in South Korea. Using PDF method and QI (quantitative index), we executed qualitative and quantitative comparisons among local areas and chemical constituents. Geochemical properties of groundwater with/without CO2 as the PDF forms proved that pH, EC, TDS, HCO3-, Ca2+, Mg2+, and SiO2 were effective monitoring parameters for carbonated groundwater in the case of CO2leakage from an underground storage site. KEY WORDS: CO2-rich groundwater, CO2 storage site, monitoring parameter, natural analogue, probability density function (PDF), QI_quantitative index Acknowledgement This study was supported by the "Basic Science Research Program through the National Research Foundation of Korea (NRF), which is funded by the Ministry of Education (NRF-2013R1A1A2058186)" and the "R&D Project on Environmental Management of Geologic CO2 Storage" from KEITI (Project number: 2014001810003).

Increased N2O emission by inhibited plant growth in the CO2 leaked soil environment: Simulation of CO2 leakage from carbon capture and storage (CCS) site.

Science.gov (United States)

Kim, You Jin; He, Wenmei; Ko, Daegeun; Chung, Haegeun; Yoo, Gayoung

2017-12-31

Atmospheric carbon dioxide (CO 2 ) concentrations is continuing to increase due to anthropogenic activity, and geological CO 2 storage via carbon capture and storage (CCS) technology can be an effective way to mitigate global warming due to CO 2 emission. However, the possibility of CO 2 leakage from reservoirs and pipelines exists, and such leakage could negatively affect organisms in the soil environment. Therefore, to determine the impacts of geological CO 2 leakage on plant and soil processes, we conducted a greenhouse study in which plants and soils were exposed to high levels of soil CO 2 . Cabbage, which has been reported to be vulnerable to high soil CO 2 , was grown under BI (no injection), NI (99.99% N 2 injection), and CI (99.99% CO 2 injection). Mean soil CO 2 concentration for CI was 66.8-76.9% and the mean O 2 concentrations in NI and CI were 6.6-12.7%, which could be observed in the CO 2 leaked soil from the pipelines connected to the CCS sites. The soil N 2 O emission was increased by 286% in the CI, where NO 3 - -N concentration was 160% higher compared to that in the control. This indicates that higher N 2 O emission from CO 2 leakage could be due to enhanced nitrification process. Higher NO 3 - -N content in soil was related to inhibited plant metabolism. In the CI treatment, chlorophyll content decreased and chlorosis appeared after 8th day of injection. Due to the inhibited root growth, leaf water and nitrogen contents were consistently lowered by 15% under CI treatment. Our results imply that N 2 O emission could be increased by the secondary effects of CO 2 leakage on plant metabolism. Hence, monitoring the environmental changes in rhizosphere would be very useful for impact assessment of CCS technology. Copyright © 2017 Elsevier B.V. All rights reserved.

Impact of CO₂ on the Evolution of Microbial Communities Exposed to Carbon Storage Conditions, Enhanced Oil Recovery, and CO₂ Leakage

Energy Technology Data Exchange (ETDEWEB)

Gulliver, Djuna [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Gregory, Kelvin B. [Carnegie Mellon Univ., Pittsburgh, PA (United States); Lowry, Gregorgy V. [Carnegie Mellon Univ., Pittsburgh, PA (United States)

2016-06-20

Geologic carbon storage (GCS) is a crucial part of a proposed mitigation strategy to reduce the anthropogenic carbon dioxide (CO₂) emissions to the atmosphere. During this process, CO₂ is injected as super critical carbon dioxide (SC-CO₂) in confined deep subsurface storage units, such as saline aquifers and depleted oil reservoirs. The deposition of vast amounts of CO₂ in subsurface geologic formations could unintentionally lead to CO₂ leakage into overlying freshwater aquifers. Introduction of CO₂ into these subsurface environments will greatly increase the CO₂2 concentration and will create CO₂ concentration gradients that drive changes in the microbial communities present. While it is expected that altered microbial communities will impact the biogeochemistry of the subsurface, there is no information available on how CO₂ gradients will impact these communities. The overarching goal of this project is to understand how CO₂ exposure will impact subsurface microbial communities at temperatures and pressures that are relevant to GCS and CO₂ leakage scenarios. To meet this goal, unfiltered, aqueous samples from a deep saline aquifer, a depleted oil reservoir, and a fresh water aquifer were exposed to varied concentrations of CO₂ at reservoir pressure and temperature. The microbial ecology of the samples was examined using molecular, DNA-based techniques. The results from these studies were also compared across the sites to determine any existing trends. Results reveal that increasing CO₂ leads to decreased DNA concentrations regardless of the site, suggesting that microbial processes will be significantly hindered or absent nearest the CO₂ injection/leakage plume where CO₂ concentrations are highest. At CO₂ exposures expected downgradient from the CO₂ plume, selected microorganisms

Impact of CO₂ on the Evolution of Microbial Communities Exposed to Carbon Storage Conditions, Enhanced Oil Recovery, and CO₂ Leakage

Energy Technology Data Exchange (ETDEWEB)

Gulliver, Djuna M. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Gregory, Kelvin B. [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Civil and Environmental Engineering; Lowry, Gregory V. [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Civil and Environmental Engineering

2016-06-20

Geologic carbon storage (GCS) is a crucial part of a proposed mitigation strategy to reduce the anthropogenic carbon dioxide (CO₂) emissions to the atmosphere. During this process, CO₂ is injected as super critical carbon dioxide (SC-CO₂) in confined deep subsurface storage units, such as saline aquifers and depleted oil reservoirs. The deposition of vast amounts of CO₂ in subsurface geologic formations could unintentionally lead to CO₂ leakage into overlying freshwater aquifers. Introduction of CO₂ into these subsurface environments will greatly increase the CO₂ concentration and will create CO₂ concentration gradients that drive changes in the microbial communities present. While it is expected that altered microbial communities will impact the biogeochemistry of the subsurface, there is no information available on how CO₂ gradients will impact these communities. The overarching goal of this project is to understand how CO₂ exposure will impact subsurface microbial communities at temperatures and pressures that are relevant to GCS and CO₂ leakage scenarios. To meet this goal, unfiltered, aqueous samples from a deep saline aquifer, a depleted oil reservoir, and a fresh water aquifer were exposed to varied concentrations of CO₂ at reservoir pressure and temperature. The microbial ecology of the samples was examined using molecular, DNA-based techniques. The results from these studies were also compared across the sites to determine any existing trends. Results reveal that increasing CO₂ leads to decreased DNA concentrations regardless of the site, suggesting that microbial processes will be significantly hindered or absent nearest the CO₂ injection/leakage plume where CO₂ concentrations are highest. At CO₂ exposures expected downgradient from the CO₂ plume, selected microorganisms

Forest succession at elevated CO2; TOPICAL

International Nuclear Information System (INIS)

Clark, James S.; Schlesinger, William H.

2002-01-01

We tested hypotheses concerning the response of forest succession to elevated CO2 in the FACTS-1 site at the Duke Forest. We quantified growth and survival of naturally recruited seedlings, tree saplings, vines, and shrubs under ambient and elevated CO2. We planted seeds and seedlings to augment sample sites. We augmented CO2 treatments with estimates of shade tolerance and nutrient limitation while controlling for soil and light effects to place CO2 treatments within the context of natural variability at the site. Results are now being analyzed and used to parameterize forest models of CO2 response

Copper nanoparticle ensembles for selective electroreduction of CO2 to C2–C3 products

Science.gov (United States)

Kley, Christopher S.; Li, Yifan; Yang, Peidong

2017-01-01

Direct conversion of carbon dioxide to multicarbon products remains as a grand challenge in electrochemical CO2 reduction. Various forms of oxidized copper have been demonstrated as electrocatalysts that still require large overpotentials. Here, we show that an ensemble of Cu nanoparticles (NPs) enables selective formation of C2–C3 products at low overpotentials. Densely packed Cu NP ensembles underwent structural transformation during electrolysis into electrocatalytically active cube-like particles intermixed with smaller nanoparticles. Ethylene, ethanol, and n-propanol are the major C2–C3 products with onset potential at −0.53 V (vs. reversible hydrogen electrode, RHE) and C2–C3 faradaic efficiency (FE) reaching 50% at only −0.75 V. Thus, the catalyst exhibits selective generation of C2–C3 hydrocarbons and oxygenates at considerably lowered overpotentials in neutral pH aqueous media. In addition, this approach suggests new opportunities in realizing multicarbon product formation from CO2, where the majority of efforts has been to use oxidized copper-based materials. Robust catalytic performance is demonstrated by 10 h of stable operation with C2–C3 current density 10 mA/cm2 (at −0.75 V), rendering it attractive for solar-to-fuel applications. Tafel analysis suggests reductive CO coupling as a rate determining step for C2 products, while n-propanol (C3) production seems to have a discrete pathway. PMID:28923930

Nuclear site selection studies

International Nuclear Information System (INIS)

Gharib, A.; Zohoorian Izadpanah, A.A.; Iranmanesh, H.

2000-01-01

It is of special importance, especially from the nuclear safety viewpoint, to select suitable sites for different nuclear structures with the considered future activities. Site selection sometimes involves high costs not necessarily for merely selecting of site but for some preliminary measures to be taken so as the site may have the necessary characteristics. The more suitable the natural characteristics of the site for the considered project, the more successful and efficient the project, the lower the project costs and the longer the project operation period. If so, the project will cause the growth of public culture and sustainable socioeconomic development. This paper is the result of the conclusion of numerous massive reports of this activity in the preliminary phase based on theories, practices and the related safety principles on this ground as well as the application of data and information of the past and a glance to the future. The conception of need for a site for medium structures and nuclear research projects and how to perform this process are presented step by step here with a scientific approach to its selection during the investigations. In this study, it is practically described how the site is selected, by determining and defining the characteristics of research and nuclear projects with medium structures and also its fitting to the optimum site. The discovered sites typically involve the best advantages in technical and economic aspects and no particular contrast with the concerned structures

High-permeance crosslinked PTMSP thin-film composite membranes as supports for CO2 selective layer formation

Directory of Open Access Journals (Sweden)

Stepan D. Bazhenov

2016-10-01

Full Text Available In the development of the composite gas separation membranes for post-combustion CO2 capture, little attention is focused on the optimization of the membrane supports, which satisfy the conditions of this technology. The primary requirements to the membrane supports are concerned with their high CO2 permeance. In this work, the membrane supports with desired characteristics were developed as high-permeance gas separation thin film composite (TFC membranes with the thin defect-free layer from the crosslinked highly permeable polymer, poly[1-(trimethylsilyl-1-propyne] (PTMSP. This layer is insoluble in chloroform and can be used as a gutter layer for the further deposition of the СО2-selective materials from the organic solvents. Crosslinking of PTMSP was performed using polyethyleneimine (PEI and poly (ethyleneglycol diglycidyl ether (PEGDGE as crosslinking agents. Optimal concentrations of PEI in PTMSP and PEGDGE in methanol were selected in order to diminish the undesirable effect on the final membrane gas transport characteristics. The conditions of the kiss-coating technique for the deposition of the thin defect-free PTMSP-based layer, namely, composition of the casting solution and the speed of movement of the porous commercial microfiltration-grade support, were optimized. The procedure of post-treatment with alcohols and alcohol solutions was shown to be crucial for the improvement of gas permeance of the membranes with the crosslinked PTMSP layer having thickness ranging within 1–2.5 μm. The claimed membranes showed the following characteristics: CO2 permeance is equal to 50–54 m3(STP/(m2 h bar (18,500–20,000 GPU, ideal CO2/N2 selectivity is 3.6–3.7, and their selective layers are insoluble in chloroform. Thus, the developed high-permeance TFC membranes are considered as a promising supports for further modification by enhanced CO2 selective layer formation. Keywords: Thin-film composite membrane

Effects of CO{sub 2} gas as leaks from geological storage sites on agro-ecosystems

Energy Technology Data Exchange (ETDEWEB)

Patil, Ravi H.; Colls, Jeremy J. [Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, NG7 2RD, Nottingham (United Kingdom); Steven, Michael D. [School of Geography, University of Nottingham, NG7 2RD, Nottingham (United Kingdom)

2010-12-15

Carbon capture and storage in geological formations has potential risks in the long-term safety because of the possibility of CO{sub 2} leakage. Effects of leaking gas, therefore, on vegetation, soil, and soil-inhabiting organisms are critical to understand. An artificial soil gassing and response detection field facility developed at the University of Nottingham was used to inject CO{sub 2} gas at a controlled flow rate (1 l min{sup -1}) into soil to simulate build-up of soil CO{sub 2} concentrations and surface fluxes from two land use types: pasture grassland, and fallow followed by winter bean. Mean soil CO{sub 2} concentrations was significantly higher in gassed pasture plots than in gassed fallow plots. Germination of winter bean sown in gassed fallow plots was severely hindered and the final crop stand was reduced to half. Pasture grass showed stress symptoms and above-ground biomass was significantly reduced compared to control plot. A negative correlation (r = -0.95) between soil CO{sub 2} and O{sub 2} concentrations indicated that injected CO{sub 2} displaced O{sub 2} from soil. Gassing CO{sub 2} reduced soil pH both in grass and fallow plots (p = 0.012). The number of earthworm castings was twice as much in gassed plots than in control plots. This study showed adverse effects of CO{sub 2} gas on agro-ecosystem in case of leakage from storage sites to surface. (author)

Thermodynamics of CoAl2O4-CoGa2O4 solid solutions

International Nuclear Information System (INIS)

Lilova, Kristina I.; Navrotsky, Alexandra; Melot, Brent C.; Seshadri, Ram

2010-01-01

CoAl 2 O 4 , CoGa 2 O 4 , and their solid solution Co(Ga z Al 1-z ) 2 O 4 have been studied using high temperature oxide melt solution calorimetry in molten 2PbO.B 2 O 3 at 973 K. There is an approximately linear correlation between lattice parameters, enthalpy of formation from oxides, and the Ga content. The experimental enthalpy of mixing is zero within experimental error. The cation distribution parameters are calculated using the O'Neill and Navrotsky thermodynamic model. The enthalpies of mixing calculated from these parameters are small and consistent with the calorimetric data. The entropies of mixing are calculated from site occupancies and compared to those for a random mixture of Ga and Al ions on octahedral site with all Co tetrahedral and for a completely random mixture of all cations on both sites. Despite a zero heat of mixing, the solid solution is not ideal in that activities do not obey Raoult's Law because of the more complex entropy of mixing. - Graphical abstract: Measured enthalpies of mixing of CoAl 2 O 4 -CoGa 2 O 4 solid solutions are close to zero but entropies of mixing reflect the complex cation distribution, so the system is not an ideal solution.

Leakage and Seepage of CO2 from Geologic Carbon Sequestration Sites: CO2 Migration into Surface Water

International Nuclear Information System (INIS)

Oldenburg, Curt M.; Lewicki, Jennifer L.

2005-01-01

Geologic carbon sequestration is the capture of anthropogenic carbon dioxide (CO 2 ) and its storage in deep geologic formations. One of the concerns of geologic carbon sequestration is that injected CO 2 may leak out of the intended storage formation, migrate to the near-surface environment, and seep out of the ground or into surface water. In this research, we investigate the process of CO 2 leakage and seepage into saturated sediments and overlying surface water bodies such as rivers, lakes, wetlands, and continental shelf marine environments. Natural CO 2 and CH 4 fluxes are well studied and provide insight into the expected transport mechanisms and fate of seepage fluxes of similar magnitude. Also, natural CO 2 and CH 4 fluxes are pervasive in surface water environments at levels that may mask low-level carbon sequestration leakage and seepage. Extreme examples are the well known volcanic lakes in Cameroon where lake water supersaturated with respect to CO 2 overturned and degassed with lethal effects. Standard bubble formation and hydrostatics are applicable to CO 2 bubbles in surface water. Bubble-rise velocity in surface water is a function of bubble size and reaches a maximum of approximately 30 cm s -1 at a bubble radius of 0.7 mm. Bubble rise in saturated porous media below surface water is affected by surface tension and buoyancy forces, along with the solid matrix pore structure. For medium and fine grain sizes, surface tension forces dominate and gas transport tends to occur as channel flow rather than bubble flow. For coarse porous media such as gravels and coarse sand, buoyancy dominates and the maximum bubble rise velocity is predicted to be approximately 18 cm s -1 . Liquid CO 2 bubbles rise slower in water than gaseous CO 2 bubbles due to the smaller density contrast. A comparison of ebullition (i.e., bubble formation) and resulting bubble flow versus dispersive gas transport for CO 2 and CH 4 at three different seepage rates reveals that

Site Selection for Surplus Plutonium Disposition Facilities at the Savannah River Site

International Nuclear Information System (INIS)

Wike, L.D.

2000-01-01

A site selection study was conducted to evaluate locations for the proposed Surplus Plutonium Disposition Facilities. Facilities to be located include the Mixed Oxide (MOX) Fuel Fabrication Facility, the Pit Disassembly and Conversion Facility (PDCF), and the Plutonium Immobilization Project (PIP) facility. Objectives of the study include: (1) Confirm that the Department of Energy (DOE) selected locations for the MOX and PDCF were suitable based on selected siting criteria, (2) Recommend a site in the vicinity of F Area that is suitable for the PIP, and (3) Identify alternative suitable sites for one or more of these facilities in the event that further geotechnical characterization or other considerations result in disqualification of a currently proposed site

The European FP7 ULTimateCO2 project: A comprehensive approach to study the long term fate of CO2 geological storage sites

Science.gov (United States)

Audigane, P.; Brown, S.; Dimier, A.; Pearce, J.; Frykman, P.; Maurand, N.; Le Gallo, Y.; Spiers, C. J.; Cremer, H.; Rutters, H.; Yalamas, T.

2013-12-01

The European FP7 ULTimateCO2 project aims at significantly advance our knowledge of specific processes that could influence the long-term fate of geologically stored CO2: i) trapping mechanisms, ii) fluid-rock interactions and effects on mechanical integrity of fractured caprock and faulted systems and iii) leakage due to mechanical and chemical damage in the well vicinity, iv) brine displacement and fluid mixing at regional scale. A realistic framework is ensured through collaboration with two demonstration sites in deep saline sandstone formations: the onshore former NER300 West Lorraine candidate in France (ArcelorMittal GeoLorraine) and the offshore EEPR Don Valley (former Hatfield) site in UK operated by National Grid. Static earth models have been generated at reservoir and basin scale to evaluate both trapping mechanisms and fluid displacement at short (injection) and long (post injection) time scales. Geochemical trapping and reservoir behaviour is addressed through experimental approaches using sandstone core materials in batch reactive mode with CO2 and impurities at reservoir pressure and temperature conditions and through geochemical simulations. Collection of data has been generated from natural and industrial (oil industry) analogues on the fluid flow and mechanical properties, structure, and mineralogy of faults and fractures that could affect the long-term storage capacity of underground CO2 storage sites. Three inter-related lines of laboratory experiments investigate the long-term evolution of the mechanical properties and sealing integrity of fractured and faulted caprocks using Opalinus clay of Mont Terri Gallery (Switzerland) (OPA), an analogue for caprock well investigated in the past for nuclear waste disposal purpose: - Characterization of elastic parameters in intact samples by measuring strain during an axial experiment, - A recording of hydraulic fracture flow properties by loading and shearing samples in order to create a 'realistic

CO2 Sparging Proof of Concept Test Report, Revision 1, LCP Chemicals Site, Brunswick, Georgia

Science.gov (United States)

April 2013 report to evaluate the feasibility of CO2 sparging to remediate a sub-surface caustic brine pool (CBP) at the LCP Chemicals Superfund Site, GA. Region ID : 04, DocID: 10940639 , DocDate: 2013-04-01

Programming MIL-101Cr for selective and enhanced CO2 adsorption at low pressure by postsynthetic amine functionalization.

Science.gov (United States)

Khutia, Anupam; Janiak, Christoph

2014-01-21

MIL-101Cr fully or partially (p) postsynthetically modified with nitro (-NO2) or amino (-NH2) groups was shown to be a robust, water stable, selective and enhanced carbon dioxide (CO2) adsorption material with the amine-functionality. The highly microporous amine-modified frameworks (up to 1.6 cm(3) g(-1) total pore volume) exhibit excellent thermal stability (>300 °C) with BET surface areas up to 2680 m(2) g(-1). At 1 bar (at 273 K) the gases CO2, CH4 and N2 are adsorbed up to 22.2 wt%, 1.67 wt% and 2.27 wt%, respectively. The two amine-modified MIL-101Cr-NH2 (4) and MIL-101Cr-pNH2 (5) showed the highest gas uptake capacities in the series with high ratios for the CO2 : N2 and CO2 : CH4 selectivities (up to 119 : 1 and 75 : 1, respectively, at 273 K). Comparison with non-modified MIL-101Cr traces the favorable CO2 adsorption properties of MIL-101Cr-NH2 (4) and MIL-101Cr-pNH2 (5) to the presence of the Lewis-basic amine groups. MIL-101Cr-NH2 (4) has a high isosteric heat of adsorption of 43 kJ mol(-1) at zero surface coverage and also >23 kJ mol(-1) over the entire adsorption range, which is well above the heat of liquefaction of bulk CO2. Large CO2 uptake capacities of amine-functionalized 4 and 5, coupled with high adsorption enthalpy, high selectivities and proven long-term water stability, make them suitable candidates for capturing CO2 at low pressure from gas mixtures including the use as a CO2 sorbent from moist air.

Flexible metal-organic framework compounds: In situ studies for selective CO{sub 2} capture

Energy Technology Data Exchange (ETDEWEB)

Allen, A.J., E-mail: andrew.allen@nist.gov [Material Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899-8520 (United States); Espinal, L.; Wong-Ng, W. [Material Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899-8520 (United States); Queen, W.L. [NIST Center for Neutron Research, Gaithersburg, MD 20899-6102 (United States); The Molecular Foundry, Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA 94720 (United States); Brown, C.M. [NIST Center for Neutron Research, Gaithersburg, MD 20899-6102 (United States); Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716 (United States); Kline, S.R. [NIST Center for Neutron Research, Gaithersburg, MD 20899-6102 (United States); Kauffman, K.L. [National Energy Technology Laboratory (NETL), US Department of Energy, Pittsburgh, PA 15236 (United States); Culp, J.T. [National Energy Technology Laboratory (NETL), US Department of Energy, Pittsburgh, PA 15236 (United States); URS Corporation, South Park, PA 15219 (United States); Matranga, C. [National Energy Technology Laboratory (NETL), US Department of Energy, Pittsburgh, PA 15236 (United States)

2015-10-25

Results are presented that explore the dynamic structural changes occurring in two highly flexible nanocrystalline metal-organic framework (MOF) compounds during the adsorption and desorption of pure gases and binary mixtures. The Ni(1,2-bis(4-pyridyl)ethylene)[Ni(CN){sub 4}] and catena-bis(dibenzoylmethanato)-(4,4′-bipyridyl)nickel(II) chosen for this study are 3-D and 1-D porous coordination polymers (PCP) with a similar gate opening pressure response for CO{sub 2} isotherms at 303 K, but with differing degrees of flexibility for structural change to accommodate guest molecules. As such, they serve as a potential model system for evaluating the complex kinetics associated with dynamic structure changes occurring in response to gas adsorption in flexible MOF systems. Insights into the crystallographic changes occurring as the MOF pore structure expands and contracts in response to interactions with CO{sub 2}, N{sub 2}, and CO{sub 2}/N{sub 2} mixtures have been obtained from in situ small-angle neutron scattering and neutron diffraction, combined with ex situ X-ray diffraction structure measurements. The role of structure in carbon capture functionality is discussed with reference to the ongoing characterization challenges and a possible materials-by-design approach. - Graphical abstract: We present in situ small-angle neutron scattering results for two flexible metal-organic frameworks (MOFs). The figure shows that for one (NiBpene, high CO{sub 2} adsorption) the intensity of the Bragg peak for the expandable d-spacing most associated with CO{sub 2} adsorption varies approximately with the isotherm, while for the other (NiDBM-Bpy, high CO{sub 2} selectivity) the d-spacing, itself, varies with the isotherm. The cartoons show the proposed modes of structural change. - Highlights: • Dynamic structures of two flexible MOF CO{sub 2} sorbent compounds are compared in situ. • These porous solid sorbents serve as models for pure & dual gas adsorption. • Different

Atmospheric inversion of the surface CO2 flux with 13CO2 constraint

Science.gov (United States)

Chen, J. M.; Mo, G.; Deng, F.

2013-10-01

Observations of 13CO2 at 73 sites compiled in the GLOBALVIEW database are used for an additional constraint in a global atmospheric inversion of the surface CO2 flux using CO2 observations at 210 sites for the 2002-2004 period for 39 land regions and 11 ocean regions. This constraint is implemented using the 13CO2/CO2 flux ratio modeled with a terrestrial ecosystem model and an ocean model. These models simulate 13CO2 discrimination rates of terrestrial photosynthesis and respiration and ocean-atmosphere diffusion processes. In both models, the 13CO2 disequilibrium between fluxes to and from the atmosphere is considered due to the historical change in atmospheric 13CO2 concentration. For the 2002-2004 period, the 13CO2 constraint on the inversion increases the total land carbon sink from 3.40 to 3.70 Pg C yr-1 and decreases the total oceanic carbon sink from 1.48 to 1.12 Pg C yr-1. The largest changes occur in tropical areas: a considerable decrease in the carbon source in the Amazon forest, and this decrease is mostly compensated by increases in the ocean region immediately west of the Amazon and the southeast Asian land region. Our further investigation through different treatments of the 13CO2/CO2 flux ratio used in the inversion suggests that variable spatial distributions of the 13CO2 isotopic discrimination rate simulated by the models over land and ocean have considerable impacts on the spatial distribution of the inverted CO2 flux over land and the inversion results are not sensitive to errors in the estimated disequilibria over land and ocean.

A Multi-scale Approach for CO2 Accounting and Risk Analysis in CO2 Enhanced Oil Recovery Sites

Science.gov (United States)

Dai, Z.; Viswanathan, H. S.; Middleton, R. S.; Pan, F.; Ampomah, W.; Yang, C.; Jia, W.; Lee, S. Y.; McPherson, B. J. O. L.; Grigg, R.; White, M. D.

2015-12-01

Using carbon dioxide in enhanced oil recovery (CO2-EOR) is a promising technology for emissions management because CO2-EOR can dramatically reduce carbon sequestration costs in the absence of greenhouse gas emissions policies that include incentives for carbon capture and storage. This study develops a multi-scale approach to perform CO2 accounting and risk analysis for understanding CO2 storage potential within an EOR environment at the Farnsworth Unit of the Anadarko Basin in northern Texas. A set of geostatistical-based Monte Carlo simulations of CO2-oil-water flow and transport in the Marrow formation are conducted for global sensitivity and statistical analysis of the major risk metrics: CO2 injection rate, CO2 first breakthrough time, CO2 production rate, cumulative net CO2 storage, cumulative oil and CH4 production, and water injection and production rates. A global sensitivity analysis indicates that reservoir permeability, porosity, and thickness are the major intrinsic reservoir parameters that control net CO2 injection/storage and oil/CH4 recovery rates. The well spacing (the distance between the injection and production wells) and the sequence of alternating CO2 and water injection are the major operational parameters for designing an effective five-spot CO2-EOR pattern. The response surface analysis shows that net CO2 injection rate increases with the increasing reservoir thickness, permeability, and porosity. The oil/CH4 production rates are positively correlated to reservoir permeability, porosity and thickness, but negatively correlated to the initial water saturation. The mean and confidence intervals are estimated for quantifying the uncertainty ranges of the risk metrics. The results from this study provide useful insights for understanding the CO2 storage potential and the corresponding risks of commercial-scale CO2-EOR fields.

Facilitated transport in hydroxide-exchange membranes for post-combustion CO2 separation.

Science.gov (United States)

Xiong, Laj; Gu, Shuang; Jensen, Kurt O; Yan, Yushan S

2014-01-01

Hydroxide-exchange membranes are developed for facilitated transport CO2 in post-combustion flue-gas feed. First, a correlation between the basicity of fixed-site functional groups and CO2 -separation performance is discovered. This relationship is used to identify phosphonium as a promising candidate to achieve high CO2 -separation performance. Consequently, quaternary phosphonium-based hydroxide-exchange membranes are demonstrated to have a separation performance that is above the Robeson upper bound. Specifically, a CO2 permeability as high as 1090 Barrer and a CO2 /N2 selectivity as high as 275 is achieved. The high performance observed in the membranes can be attributed to the quaternary phosphonium moiety. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Superior capture of CO2 achieved by introducing extra-framework cations into N-doped microporous carbon

KAUST Repository

Zhao, Yunfeng

2012-12-21

We designed and prepared a novel microporous carbon material (KNC-A-K) for selective CO2 capture. The combination of a high N-doping concentration (>10 wt %) and extra-framework cations, which were introduced into carbonaceous sorbents for the first time, endowed KNC-A-K with exceptional CO2 adsorption capabilities, especially at low pressures. Specifically, KNC-A-K exhibited CO2 uptake of 1.62 mmol g -1 at 25 C and 0.1 bar, far exceeding the CO2 adsorption capability of most reported carbon material to date. Single component adsorption isotherms indicated that its CO2/N2 selectivity was 48, which also significantly surpasses the selectivity of conventional carbon materials. Furthermore, breakthrough experiments were conducted to evaluate the CO2 separation capability of KNC-A-K on CO2/N2 (10:90 v/v) mixtures under kinetic flow conditions, and the obtained CO 2/N2 selectivity was as high as 44, comparable to that predicted from equilibrium adsorption data. Upon facile regeneration, KNC-A-K showed constant CO2 adsorption capacity and selectivity during multiple mixed-gas separation cycles. Its outstanding low-pressure CO 2 adsorption ability makes KNC-A-K a promising candidate for selective CO2 capture from flue gas. Theoretical calculations indicated that K+ ions play a key role in promoting CO2 adsorption via electrostatic interactions. In addition, we found that HCl molecules anchored in N-doped carbon have a similar promotion effect on CO 2 adsorption, which contradicts the conventional wisdom that the neutralization of basic sites by acids diminishes the adsorption of acidic CO2 gas. © 2012 American Chemical Society.

Influence of air mass source sector on variations in CO2 mixing ratio at a boreal site in northern Finland

International Nuclear Information System (INIS)

Aalto, T.; Hatakka, J.; Viisanen, Y.

2003-01-01

CO 2 mixing ratio in air masses coming from different source sectors was studied at Pallas measurement station in Lapland. Source sectors were defined using back trajectories and wind direction measurements. Air masses from the North and West sectors showed an annual variation of 17 ppm, possibly affected by a long range transported marine air. A larger variation of 20 ppm was observed in air masses from the more continental South and East sectors. During late autumn mixing ratios in air masses from the South sector were high in comparison with the other sectors. Different methods for a source sector definition were considered for the site, located in a contoured terrain. 52%-73% of wind direction-based source sector definitions agreed with trajectory- based definitions. However, the number of cases with reliable sector definitions may remain low when considering all observations. Different definition methods can cause differences of the order of 1 ppm in sectorially selected monthly mean CO 2 mixing ratios. (orig.)

Measurement of residual CO2 saturation at a geological storage site using hydraulic tests

Science.gov (United States)

Rötting, T. S.; Martinez-Landa, L.; Carrera, J.; Russian, A.; Dentz, M.; Cubillo, B.

2012-12-01

Estimating long term capillary trapping of CO2 in aquifers remains a key challenge for CO2 storage. Zhang et al. (2011) proposed a combination of thermal, tracer, and hydraulic experiments to estimate the amount of CO2 trapped in the formation after a CO2 push and pull test. Of these three types of experiments, hydraulic tests are the simplest to perform and possibly the most informative. However, their potential has not yet been fully exploited. Here, a methodology is presented to interpret these tests and analyze which parameters can be estimated. Numerical and analytical solutions are used to simulate a continuous injection in a porous medium where residual CO2 has caused a reduction in hydraulic conductivity and an increase in storativity over a finite thickness (a few meters) skin around the injection well. The model results are interpreted using conventional pressure build-up and diagnostic plots (a plot of the drawdown s and the logarithmic derivative d s / d ln t of the drawdown as a function of time). The methodology is applied using the hydraulic parameters estimated for the Hontomin site (Northern Spain) where a Technology Demonstration Plant (TDP) for geological CO2 storage is planned to be set up. The reduction of hydraulic conductivity causes an increase in observed drawdowns, the increased storativity in the CO2 zone causes a delay in the drawdown curve with respect to the reference curve measured before CO2 injection. The duration (characteristic time) of these effects can be used to estimate the radius of the CO2 zone. The effects of reduced permeability and increased storativity are well separated from wellbore storage and natural formation responses, even if the CO2-brine interface is inclined (i.e. the CO2 forms a cone around the well). We find that both skin hydraulic conductivity and storativity (and thus residual CO2 saturation) can be obtained from the water injection test provided that water flow rate is carefully controlled and head build

Highly CO2-Selective Gas Separation Membranes Based on Segmented Copolymers of Poly(Ethylene oxide) Reinforced with Pentiptycene-Containing Polyimide Hard Segments.

Science.gov (United States)

Luo, Shuangjiang; Stevens, Kevin A; Park, Jae Sung; Moon, Joshua D; Liu, Qiang; Freeman, Benny D; Guo, Ruilan

2016-01-27

Poly(ethylene oxide) (PEO)-containing polymer membranes are attractive for CO2-related gas separations due to their high selectivity toward CO2. However, the development of PEO-rich membranes is frequently challenged by weak mechanical properties and a high crystallization tendency of PEO that hinders gas transport. Here we report a new series of highly CO2-selective, amorphous PEO-containing segmented copolymers prepared from commercial Jeffamine polyetheramines and pentiptycene-based polyimide. The copolymers are much more mechanically robust than the nonpentiptycene containing counterparts due to the molecular reinforcement mechanism of supramolecular chain threading and interlocking interactions induced by the pentiptycene structures, which also effectively suppresses PEO crystallization leading to a completely amorphous structure even at 60% PEO weight content. Membrane transport properties are sensitively affected by both PEO weight content and PEO chain length. A nonlinear correlation between CO2 permeability with PEO weight content was observed due to the competition between solubility and diffusivity contributions, whereby the copolymers change from being size-selective to solubility-selective when PEO content reaches 40%. CO2 selectivities over H2 and N2 increase monotonically with both PEO content and chain length, indicating strong CO2-philicity of the copolymers. The copolymer film with the longest PEO sequence (PEO2000) and highest PEO weight content (60%) showed a measured CO2 pure gas permeability of 39 Barrer, and ideal CO2/H2 and CO2/N2 selectivities of 4.1 and 46, respectively, at 35 °C and 3 atm, making them attractive for hydrogen purification and carbon capture.

Assessing reservoir performance risk in CO2 storage projects

International Nuclear Information System (INIS)

Bowden, A.R.; Rigg, A.

2005-01-01

One of the main issues for researchers involved with geological storage of carbon dioxide (CO 2 ) has been the development of a proper methodology to assess and compare alternative CO 2 injection projects on the basis of risk. Consideration needs to be given to technical aspects, such as the risk of leakage and the effectiveness of the intended reservoir, as well as less tangible aspects such as the value and safety of geological storage of CO 2 , and potential impacts on the community and environment. The Geological Disposal of Carbon Dioxide (GEODISC), was a research program of the Australian Petroleum Cooperative Research Centre which identified 56 potential environmentally sustainable sites for CO 2 injection (ESSCIs) within Australia. Several studies were carried out, involving detailed evaluation of the suitability of 4 selected sites, including Dongara, Petrel, Gippsland and Carnarvon. The GEODISC program included a risk assessment research module which required a complete and quantified risk assessment of CO 2 injection as a storage option. Primary goals were to assess the risk of leakage, to assess the effectiveness of the intended reservoir, and to assess negative consequences to facilitate comparison of alternative sites. This paper discussed the background and risk assessment model. Key performance indicators (KPIs) were also developed to address the purpose of risk assessment. It was concluded that the RISQUE method is an appropriate approach and that potential injection projects can be measured against six KPIs including containment; effectiveness; self-funding potential; wider community benefits; community safety and community amenity. 6 refs., 3 tabs., 3 figs

Synthesis of basalt fiber@Zn{sub 1-x}Mg{sub x}O core/shell nanostructures for selective photoreduction of CO{sub 2} to CO

Energy Technology Data Exchange (ETDEWEB)

Kwak, Byeong Sub; Kim, Kang Min [Department of Chemistry, College of Science, Yeungnam University, Gyeongsan, Gyeongbuk 38541 (Korea, Republic of); Park, Sun-Min, E-mail: psm@kicet.re.kr [Korea Institute of Ceramic Engineering and Technology (KICET), Jinju, Gyeongnam 52851 (Korea, Republic of); Kang, Misook, E-mail: mskang@ynu.ac.kr [Department of Chemistry, College of Science, Yeungnam University, Gyeongsan, Gyeongbuk 38541 (Korea, Republic of)

2017-06-15

Highlights: • ZnO and Zn{sub 1-x}Mg{sub x}O crystals were grown onto the BFs. • The core@shell structured BF@Zn{sub 1-x}Mg{sub x}O particles significantly increased the adsorption of CO{sub 2} gas. • The BF@ZnO or BF@Zn{sub 1-x}Mg{sub x}O particles selectively reduce the carbon dioxide to carbon monoxide. - Abstract: This study focused on the development of a catalyst for converting carbon dioxide, the main cause of global warming, into a beneficial energy source. Core@shell structured particles, BF@ZnO and BF@Zn{sub 1-x}Mg{sub x}O, are synthesized in order to selectively obtain CO gas from the photoreduction of CO{sub 2}. A modified sol-gel process is used to synthesize the core@shell structures with a three-dimensional microstructure, which are subsequently characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDAX), ultraviolet (UV)–vis absorption, photoluminescence (PL), and photocurrent density analysis. The CO{sub 2} adsorption abilities of the core@shell particles are estimated through CO{sub 2}-temperature programmed desorption (TPD). The core@shell structured BF@Zn{sub 1-x}Mg{sub x}O particles including the Mg ingredient significantly increased the adsorption of CO{sub 2} gas at the microfiber/nanoparticle interface. Both the BF@ZnO and BF@Zn{sub 1-x}Mg{sub x}O particles selectively reduce the carbon dioxide to carbon monoxide, with almost no other reduced products being observed. These results are attributed to the effective adsorption of CO{sub 2} gas and inhibited recombination of the photogenerated electron–hole pairs. BF@Zn{sub 0.75}Mg{sub 0.25}O exhibited superior photocatalytic behavior and selectively produced 5.0 μmolg{sub cat}{sup −1} L{sup −1} of CO gas after 8 h of reaction.

SiteChar. Characterisation of European CO2 storage. Deliverable 8.4. Quantitative social site characterisations

Energy Technology Data Exchange (ETDEWEB)

Brunsting, S.; Mastop, E.A. [ECN Policy Studies, Energy research Centre of the Netherlands ECN, Amsterdam (Netherlands); Kaiser, M.; Zimmer, R. [Unabhaengiges Institut fuer Umweltfragen UfU, Berlin (Germany)

2013-06-15

This report describes the results of the last stage of the in-depth social site characterisation activities at two prospective CCS sites as part of the SiteChar project: a CCS onshore site and a CCS offshore site. The onshore site is the Zalecze and Zuchlow site application (Poland - WP5) and the offshore site is the North Sea Moray Firth site (UK - WP3). This deliverable describes the results from a repeated quantitative measurement of local awareness, knowledge, and perceptions of CCS at both sites using representative surveys. For comparison and discussion of all SiteChar WP8 results we refer to the final summary report D8.5. The 2nd survey showed some interesting results. First of all, awareness of CCS was still very low. While in the UK around half of the respondents had at least heard of local plans for CCS, in Poland this was only 21%. It seems that awareness in the UK was mostly induced by specific plans in the area that were abandoned in the course of the SiteChar project. Second, it seems that on the whole the local publics were rather positive about CCS. Most respondents expected a positive impact of CCS on the region. In the UK, arguments for that were mainly economic, while in Poland arguments were mainly related to environmental concerns. Although there are some worries about risks of leakage, especially at the onshore site in Poland, people think that authorities will properly regulate CCS and monitor the safety of CCS. Expectations were mostly that it would be good for the country and that it will help reach international targets for CO2 reduction and buy time to develop renewable energy. Respondents seemed uncertain about the costs of using CCS and whether the technique is ready for widespread use. Especially in Poland people seemed to agree that CCS is essential for tackling climate change. Most differences between the two sites may be attributed to the proximity of the site to the local community. The Polish site is onshore and therefore much

Surface CO2 leakage during the first shallow subsurface CO2 release experiment

OpenAIRE

Lewicki, J.L.; Oldenburg, C.; Dobeck, L.; Spangler, L.

2008-01-01

A new field facility was used to study CO2 migration processes and test techniques to detect and quantify potential CO2 leakage from geologic storage sites. For 10 days starting 9 July 2007, and for seven days starting 5 August 2007, 0.1 and 0.3 t CO2 d-1, respectively, were released from a ~;100-m long, sub-water table (~;2.5-m depth) horizontal well. The spatio-temporal evolution of leakage was mapped through repeated grid measurements of soil CO2 flux (FCO2). The surface leakage onset...

Permeability and Selectivity of PPO/Graphene Composites as Mixed Matrix Membranes for CO2 Capture and Gas Separation

Directory of Open Access Journals (Sweden)

Riccardo Rea

2018-01-01

Full Text Available We fabricated novel composite (mixed matrix membranes based on a permeable glassy polymer, Poly(2,6-dimethyl-1,4-phenylene oxide (PPO, and variable loadings of few-layer graphene, to test their potential in gas separation and CO2 capture applications. The permeability, selectivity and diffusivity of different gases as a function of graphene loading, from 0.3 to 15 wt %, was measured at 35 and 65 °C. Samples with small loadings of graphene show a higher permeability and He/CO2 selectivity than pure PPO, due to a favorable effect of the nanofillers on the polymer morphology. Higher amounts of graphene lower the permeability of the polymer, due to the prevailing effect of increased tortuosity of the gas molecules in the membrane. Graphene also allows dramatically reducing the increase of permeability with temperature, acting as a “stabilizer” for the polymer matrix. Such effect reduces the temperature-induced loss of size-selectivity for He/N2 and CO2/N2, and enhances the temperature-induced increase of selectivity for He/CO2. The study confirms that, as observed in the case of other graphene-based mixed matrix glassy membranes, the optimal concentration of graphene in the polymer is below 1 wt %. Below such threshold, the morphology of the nanoscopic filler added in solution affects positively the glassy chains packing, enhancing permeability and selectivity, and improving the selectivity of the membrane at increasing temperatures. These results suggest that small additions of graphene to polymers can enhance their permselectivity and stabilize their properties.

Porous Organic Polymers for CO2 Capture

KAUST Repository

Teng, Baiyang

2013-05-01

Carbon dioxide (CO2) has long been regarded as the major greenhouse gas, which leads to numerous negative effects on global environment. The capture and separation of CO2 by selective adsorption using porous materials proves to be an effective way to reduce the emission of CO2 to atmosphere. Porous organic polymers (POPs) are promising candidates for this application due to their readily tunable textual properties and surface functionalities. The objective of this thesis work is to develop new POPs with high CO2 adsorption capacities and CO2/N2 selectivities for post-combustion effluent (e.g. flue gas) treatment. We will also exploit the correlation between the CO2 capture performance of POPs and their textual properties/functionalities. Chapters Two focuses on the study of a group of porous phenolic-aldehyde polymers (PPAPs) synthesized by a catalyst-free method, the CO2 capture capacities of these PPAPs exceed 2.0 mmol/g at 298 K and 1 bar, while keeping CO2/N2 selectivity of more than 30 at the same time. Chapter Three reports the gas adsorption results of different hyper-cross-linked polymers (HCPs), which indicate that heterocyclo aromatic monomers can greatly enhance polymers’ CO2/N2 selectivities, and the N-H bond is proved to the active CO2 adsorption center in the N-contained (e.g. pyrrole) HCPs, which possess the highest selectivities of more than 40 at 273 K when compared with other HCPs. Chapter Four emphasizes on the chemical modification of a new designed polymer of intrinsic microporosity (PIM) with high CO2/N2 selectivity (50 at 273 K), whose experimental repeatability and chemical stability prove excellent. In Chapter Five, we demonstrate an improvement of both CO2 capture capacity and CO2/N2 selectivity by doping alkali metal ions into azo-polymers, which leads a promising method to the design of new porous organic polymers.

Catalytic Hydrogenation of CO2 to Methanol: Study of Synergistic Effect on Adsorption Properties of CO2 and H2 in CuO/ZnO/ZrO2 System

Directory of Open Access Journals (Sweden)

Chunjie Huang

2015-11-01

Full Text Available A series of CuO/ZnO/ZrO2 (CZZ catalysts with different CuO/ZnO weight ratios have been synthesized by citrate method and tested in the catalytic hydrogenation of CO2 to methanol. Experimental results showed that the catalyst with the lowest CuO/ZnO weight ratio of 2/7 exhibited the best catalytic performance with a CO2 conversion of 32.9%, 45.8% methanol selectivity, and a process delivery of 193.9 gMeOH·kgcat−1·h−1. A synergetic effect is found by systematic temperature-programmed-desorption (TPD studies. Comparing with single and di-component systems, the interaction via different components in a CZZ system provides additional active sites to adsorb more H2 and CO2 in the low temperature range, resulting in higher weight time yield (WTY of methanol.

Enhanced Selectivity of the Separation of CO2 from N2 during Crystallization of Semi-Clathrates from Quaternary Ammonium Solutions

International Nuclear Information System (INIS)

Herri, J.M.; Bouchemoua, A.; Kwaterski, M.; Brantuas, P.; Galfre, A.; Bouillot, B.; Douzet, J.; Ouabbas, Y.; Cameirao, A.

2014-01-01

CO 2 mitigation is crucial environmental problem and a societal challenge for this century. CO 2 capture and sequestration is a route to solve a part of the problem, especially for the industries in which the gases to be treated are well localized. CO 2 capture by using hydrate is a process in which the cost of the separation is due to compression of gases to reach the gas hydrate formation conditions. Under pressure, the water and gas forms a solid that encapsulates preferentially CO 2 . The gas hydrate formation requires high pressures and low temperatures, which explains the use of thermodynamic promoters to decrease the operative pressure. Quaternary ammonium salts represent an interesting family of components because of their thermodynamic effect, but also because they can generate crystals that are easily handled. In this work, we have made experiments concerning the equilibrium of (CO 2 , N 2 ) in presence of Tetra-n-Butyl Ammonium Bromide (TBAB) which form a semi-clathrate hydrate. We propose equilibrium data (pressure, temperature) in presence of TBAB at different concentrations and we compare them to the literature. We have also measured the composition of the hydrate phase in equilibrium with the gas phase at different CO 2 concentrations. We observe that the selectivity of the separation is dramatically increased in comparison to the selectivity of the pure water gas clathrate hydrate. We observe also a benefice on the operative pressure which can be dropped down to the atmospheric pressure. (authors)

Analysis of CO2 Separation from Flue Gas, Pipeline Transportation, and Sequestration in Coal

Energy Technology Data Exchange (ETDEWEB)

Eric P. Robertson

2007-09-01

This report was written to satisfy a milestone of the Enhanced Coal Bed Methane Recovery and CO2 Sequestration task of the Big Sky Carbon Sequestration project. The report begins to assess the costs associated with separating the CO2 from flue gas and then injecting it into an unminable coal seam. The technical challenges and costs associated with CO2 separation from flue gas and transportation of the separated CO2 from the point source to an appropriate sequestration target was analyzed. The report includes the selection of a specific coal-fired power plant for the application of CO2 separation technology. An appropriate CO2 separation technology was identified from existing commercial technologies. The report also includes a process design for the chosen technology tailored to the selected power plant that used to obtain accurate costs of separating the CO2 from the flue gas. In addition, an analysis of the costs for compression and transportation of the CO2 from the point-source to an appropriate coal bed sequestration site was included in the report.

Highly Surface-Active Ca(OH)2 Monolayer as a CO2 Capture Material.

Science.gov (United States)

Özçelik, V Ongun; Gong, Kai; White, Claire E

2018-03-14

Greenhouse gas emissions originating from fossil fuel combustion contribute significantly to global warming, and therefore the design of novel materials that efficiently capture CO 2 can play a crucial role in solving this challenge. Here, we show that reducing the dimensionality of bulk crystalline portlandite results in a stable monolayer material, named portlandene, that is highly effective at capturing CO 2 . On the basis of theoretical analysis comprised of ab initio quantum mechanical calculations and force-field molecular dynamics simulations, we show that this single-layer phase is robust and maintains its stability even at high temperatures. The chemical activity of portlandene is seen to further increase upon defect engineering of its surface using vacancy sites. Defect-containing portlandene is capable of separating CO and CO 2 from a syngas (CO/CO 2 /H 2 ) stream, yet is inert to water vapor. This selective behavior and the associated mechanisms have been elucidated by examining the electronic structure, local charge distribution, and bonding orbitals of portlandene. Additionally, unlike conventional CO 2 capturing technologies, the regeneration process of portlandene does not require high temperature heat treatment because it can release the captured CO 2 by application of a mild external electric field, making portlandene an ideal CO 2 capturing material for both pre- and postcombustion processes.

Modeling and Evaluation of Geophysical Methods for Monitoring and Tracking CO2 Migration

Energy Technology Data Exchange (ETDEWEB)

Daniels, Jeff

2012-11-30

Geological sequestration has been proposed as a viable option for mitigating the vast amount of CO{sub 2} being released into the atmosphere daily. Test sites for CO{sub 2} injection have been appearing across the world to ascertain the feasibility of capturing and sequestering carbon dioxide. A major concern with full scale implementation is monitoring and verifying the permanence of injected CO{sub 2}. Geophysical methods, an exploration industry standard, are non-invasive imaging techniques that can be implemented to address that concern. Geophysical methods, seismic and electromagnetic, play a crucial role in monitoring the subsurface pre- and post-injection. Seismic techniques have been the most popular but electromagnetic methods are gaining interest. The primary goal of this project was to develop a new geophysical tool, a software program called GphyzCO2, to investigate the implementation of geophysical monitoring for detecting injected CO{sub 2} at test sites. The GphyzCO2 software consists of interconnected programs that encompass well logging, seismic, and electromagnetic methods. The software enables users to design and execute 3D surface-to-surface (conventional surface seismic) and borehole-to-borehole (cross-hole seismic and electromagnetic methods) numerical modeling surveys. The generalized flow of the program begins with building a complex 3D subsurface geological model, assigning properties to the models that mimic a potential CO{sub 2} injection site, numerically forward model a geophysical survey, and analyze the results. A test site located in Warren County, Ohio was selected as the test site for the full implementation of GphyzCO2. Specific interest was placed on a potential reservoir target, the Mount Simon Sandstone, and cap rock, the Eau Claire Formation. Analysis of the test site included well log data, physical property measurements (porosity), core sample resistivity measurements, calculating electrical permittivity values, seismic data

Effect of CO{sub 2} and H{sub 2}O content in syngas on activity and selectivity of a cobalt based Fischer-Tropsch synthesis catalyst

Energy Technology Data Exchange (ETDEWEB)

Poehlmann, F.; Kaiser, P.; Kern, C.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

2013-11-01

When liquid hydrocarbons are to be used as CO{sub 2} neutral storage media for electrical energy, it is necessary to convert CO{sub 2} from e.g. flue gas and hydrogen from water electrolysis to synthesis gas (CO/H{sub 2}). This can be achieved by a high temperature reverse water gas shift (RWGS) reaction. Due to thermodynamic limitations, the product gas of RWGS reactors operated at technically feasible temperatures of around 900 C will always contain significant amounts of water and carbon dioxide, which can influence the activity of Fischer-Tropsch synthesis (FTS) catalysts for the actual hydrocarbon production. In this study, a commercial cobalt catalyst was investigated under low temperature FTS conditions (2.5 MPa, 215 C) regard to activity and selectivity in the presence of H{sub 2}O and CO{sub 2}. A continuous flow apparatus including a fixed-bed reactor for the synthesis step was used to conduct all experiments. The experimental data reveals that the CO/CO{sub 2}-ratio does not affect the activity and product selectivity until the CO{sub 2}-concentration reaches 75 vol.-% (CO{sub 2}/(CO+CO{sub 2})). On increasing the carbon dioxide concentration to 100 vol.-% (H{sub 2}/CO{sub 2} = 2), the methane selectivity rose up to 70 % and even above. Addition of water caused an initial loss of activity. After the initial loss of activity the FT catalyst activity was found to remain constant, irrespectively of if the water was removed from the feed or not. Thus, the deactivation was permanent. (orig.)

Simultaneous Reduction of CO 2 and Splitting of H 2 O by a Single Immobilized Cobalt Phthalocyanine Electrocatalyst

KAUST Repository

Morlanés, Natalia

2016-04-12

Perfluorinated cobalt phthalocyanine (CoFPc) immobilized on carbon electrodes was found to electrocatalyze the reduction of CO2 selectively to CO in an aqueous solution. The conversion of CO2 became apparent at -0.5 V vs RHE, and the Faradaic efficiency for the CO production reached as high as 93% at -0.8 V vs RHE. Highly stable electrolysis of CO2/H2O into CO/O2 was achieved for 12 h by applying the same catalyst as the cathode for CO2 reduction and the anode for water oxidation. This result indicates the highly robust nature of the CoFPc at wide range of potentials from -0.9 V to +2.2 V vs RHE, demonstrating the potential bipolar electrolytic system for CO2/H2O electrolysis, using the single-site molecular CoFPc-based electrocatalyst, which is simple, inexpensive, robust, and efficient. © 2016 American Chemical Society.

Characterization of hydrotalcite materials for CO2 selective membranes

Energy Technology Data Exchange (ETDEWEB)

Feuillade, V.C.; Haije, W.G. [ECN Hydrogen and Clean Fossil Fuels, Petten (Netherlands)

2006-07-15

The present concern about climate change has urged researchers and engineers all over the world to go and look for ways of reducing greenhouse gas emissions. Largescale CO2 emissions occur at power plants burning fossil fuels or e.g. the production of hydrogen from carbonaceous feed. In these cases pre- or post-combustion CO2 capture techniques followed by CO2 storage seems a promising route for reducing emissions. Prerequisite in these processes is the effective separation of CO2 from mixed gaseous process streams. The purpose of this work is to develop CO2 membranes to allow for the combination of natural gas reforming with separation of H2 and CO2 in separation enhanced reactors, i.e. membrane reactors, for carbon-free hydrogen production or electricity generation. This paper describes the materials' properties of hydrotalcites, a promising class of compounds for CO2 membranes. They have already proven their applicability as CO2 sorbent in sorption enhanced reaction processes. It is of fundamental importance to know the structural stability of this compound in the operational window of a chosen membrane reactor prior to any membrane fabrication. To this end, in-situ XRPD and DRIFTS as well as TGA-MS and SEM-EDX measurements have been performed on commercial (Pural) and hydrothermally synthesized homemade samples.

Surface monitoring of microseismicity at the Decatur, Illinois, CO2 sequestration demonstration site

Science.gov (United States)

Kaven, Joern; Hickman, Stephen H.; McGarr, Arthur F.; Ellsworth, William L.

2015-01-01

Sequestration of CO2 into subsurface reservoirs can play an important role in limiting future emission of CO2 into the atmosphere (e.g., Benson and Cole, 2008). For geologic sequestration to become a viable option to reduce greenhouse gas emissions, large-volume injection of supercritical CO2 into deep sedimentary formations is required. These formations offer large pore volumes and good pore connectivity and are abundant (Bachu, 2003; U.S. Geological Survey Geologic Carbon Dioxide Storage Resources Assessment Team, 2013). However, hazards associated with injection of CO2 into deep formations require evaluation before widespread sequestration can be adopted safely (Zoback and Gorelick, 2012). One of these hazards is the potential to induce seismicity on pre-existing faults or fractures. If these faults or fractures are large and critically stressed, seismic events can occur with magnitudes large enough to pose a hazard to surface installations and, possibly more critical, the seal integrity of the cap rock. The Decatur, Illinois, carbon capture and storage (CCS) demonstration site is the first, and to date, only CCS project in the United States that injects a large volume of supercritical CO2 into a regionally extensive, undisturbed saline formation. The first phase of the Decatur CCS project was completed in November 2014 after injecting a million metric tons of supercritical CO2 over three years. This phase was led by the Illinois State Geological Survey (ISGS) and included seismic monitoring using deep borehole sensors, with a few sensors installed within the injection horizon. Although the deep borehole network provides a more comprehensive seismic catalog than is presented in this paper, these deep data are not publically available. We contend that for monitoring induced microseismicity as a possible seismic hazard and to elucidate the general patterns of microseismicity, the U.S. Geological Survey (USGS) surface and shallow borehole network described below

Experimental Determination and Modeling of the Phase Behavior for the Selective Oxidation of Benzyl Alcohol in Supercritical CO2

DEFF Research Database (Denmark)

Tsivintzelis, Ioannis; Beier, Matthias Josef; Grunwaldt, Jan-Dierk

2011-01-01

In this study the phase behavior of mixtures relevant to the selective catalytic oxidation of benzyl alcohol to benzaldehyde by molecular oxygen in supercritical CO2 is investigated. Initially, the solubility of N2 in benzaldehyde as well as the dew points of CO2–benzyl alcohol–O2 and CO2...

CO2 methanation on the catalyst of Ni/MCM-41 promoted with CeO2.

Science.gov (United States)

Wang, Xiaoliu; Zhu, Lingjun; Liu, Yincong; Wang, Shurong

2018-06-01

CO 2 as a raw feed combined with renewable hydrogen for the production of useful chemicals and alternative energy products is one of the solutions to environmental and energy problems. In this study, a series of Ni-xCeO 2 /MCM-41 catalysts with a nickel content of 20wt% were prepared through deposition precipitation method for CO 2 methanation. Different characterization methods, including BET, XRD, TEM, SEM, H 2 -TPR and H 2 -TPD were applied to help explore the influence mechanism of CeO 2 on Ni/MCM-41 in CO 2 methanation. It was found that all CeO 2 -promoted catalysts exhibited enhanced catalytic activity when compared to Ni/MCM-41. The catalyst modified with 20wt% CeO 2 showed the best catalytic performance, with CO 2 conversion and CH 4 selectivity of 85.6% and 99.8%, respectively, at the temperature of 380°C under atmospheric pressure. The synergetic effects among Ni 0 active sites, the promoter and the support, including nickel dispersion improvement and increased CO 2 adsorption sites due to the addition of CeO 2 , were considered as important factors for high reactivity of the promoted catalysts. The stability test showed that the promoted catalyst maintained its high reactivity after 30h. Copyright © 2017 Elsevier B.V. All rights reserved.

Selective Reversible Absorption of the Industrial Off-Gas Components CO2 and NOx by Ionic Liquids

DEFF Research Database (Denmark)

Kaas-Larsen, Peter Kjartan; Thomassen, P.; Schill, Leonhard

2016-01-01

Ionic liquids are promising new materials for climate and pollution control by selective absorption of CO2 and NOx in industrial off-gases. In addition practical cleaning of industrial off gases seems to be attractive by use of ionic liquids distributed on the surface of porous, high surface area...... carriers in the form of so-called Supported Ionic Liquid Phase (SILP) materials. The potential of selected ionic liquids for absorption of CO2 and NOx are demonstrated and the possible interference of other gases influencing the stability and absorption capacity of the ionic liquids are investigated...

Cobaltoporphyrin-Catalyzed CO 2 /Epoxide Copolymerization: Selectivity Control by Molecular Design

KAUST Repository

Anderson, Carly E.; Vagin, Sergei I.; Xia, Wei; Jin, Hanpeng; Rieger, Bernhard

2012-01-01

A series of cobalt(III) chloride porphyrin complexes of the general formula 5,10,15,20-tetra(p-alkoxy)phenylporphyrin cobalt chloride (4b-e) and the related 5,10,15,20-tetra(p-nitro)phenylporphyrin cobalt chloride (4f) are presented and their reactivity toward propylene oxide (PO)/CO 2 coupling/copolymerization is explored. While the nitro-substituted complex (4f), in conjunction with an onium salt, shows moderate activity toward cyclization, the 4b-e/onium systems show superior copolymerization activity in comparison to tetraphenylporphyrin Co(III) chloride (4a) with high selectivity and conversion to poly(propylene carbonate) (PPC). A comprehensive copolymerization behavior study of the alkoxy-substituted porphyrin complexes 4b-e in terms of reaction temperature and CO 2 pressure is presented. Complexes bearing longer alkoxy-substituents demonstrate the highest polymerization activity and molecular weights, however all substituted catalyst systems display a reduced tolerance to increased temperature with respect to PPC formation. Studies of the resulting polymer microstructures show excellent head-to-tail epoxide incorporation and near perfectly alternating poly(carbonate) character at lower polymerization temperatures. © 2012 American Chemical Society.

Cobaltoporphyrin-Catalyzed CO 2 /Epoxide Copolymerization: Selectivity Control by Molecular Design

KAUST Repository

Anderson, Carly E.

2012-09-11

A series of cobalt(III) chloride porphyrin complexes of the general formula 5,10,15,20-tetra(p-alkoxy)phenylporphyrin cobalt chloride (4b-e) and the related 5,10,15,20-tetra(p-nitro)phenylporphyrin cobalt chloride (4f) are presented and their reactivity toward propylene oxide (PO)/CO 2 coupling/copolymerization is explored. While the nitro-substituted complex (4f), in conjunction with an onium salt, shows moderate activity toward cyclization, the 4b-e/onium systems show superior copolymerization activity in comparison to tetraphenylporphyrin Co(III) chloride (4a) with high selectivity and conversion to poly(propylene carbonate) (PPC). A comprehensive copolymerization behavior study of the alkoxy-substituted porphyrin complexes 4b-e in terms of reaction temperature and CO 2 pressure is presented. Complexes bearing longer alkoxy-substituents demonstrate the highest polymerization activity and molecular weights, however all substituted catalyst systems display a reduced tolerance to increased temperature with respect to PPC formation. Studies of the resulting polymer microstructures show excellent head-to-tail epoxide incorporation and near perfectly alternating poly(carbonate) character at lower polymerization temperatures. © 2012 American Chemical Society.

Nanoporous Copper-Silver Alloys by Additive-Controlled Electrodeposition for the Selective Electroreduction of CO2 to Ethylene and Ethanol.

Science.gov (United States)

Hoang, Thao T H; Verma, Sumit; Ma, Sichao; Fister, Tim T; Timoshenko, Janis; Frenkel, Anatoly I; Kenis, Paul J A; Gewirth, Andrew A

2018-05-02

Electrodeposition of CuAg alloy films from plating baths containing 3,5-diamino-1,2,4-triazole (DAT) as an inhibitor yields high surface area catalysts for the active and selective electroreduction of CO 2 to multicarbon hydrocarbons and oxygenates. EXAFS shows the co-deposited alloy film to be homogeneously mixed. The alloy film containing 6% Ag exhibits the best CO 2 electroreduction performance, with the Faradaic efficiency for C 2 H 4 and C 2 H 5 OH production reaching nearly 60 and 25%, respectively, at a cathode potential of just -0.7 V vs RHE and a total current density of ∼ - 300 mA/cm 2 . Such high levels of selectivity at high activity and low applied potential are the highest reported to date. In situ Raman and electroanalysis studies suggest the origin of the high selectivity toward C 2 products to be a combined effect of the enhanced stabilization of the Cu 2 O overlayer and the optimal availability of the CO intermediate due to the Ag incorporated in the alloy.

A supply chain optimization framework for CO2 emission reduction: Case of the Netherlands

OpenAIRE

Kalyanarengan Ravi, N.; Zondervan, E.; van Sint Annaland, M.; Fransoo, J.C.; Grievink, J.; Claus, T.; Herrmann, F.; Manitz, M.; Rose, O.

2016-01-01

A major challenge for the industrial deployment of a CO2 emission reduction methodology is to reduce the overall cost and the integration of all the nodes in the supply chain for CO2 emission reduction. In this work, we develop a mixed integer linear optimization model that selects appropriate sources, capture process, transportation network and CO2 storage sites and optimize for a minimum overall cost. Initially, we screen the sources and storage options available in the Netherlands at diffe...

Molecular simulations of a CO2/CO mixture in MIL-127

Science.gov (United States)

Chokbunpiam, Tatiya; Fritzsche, Siegfried; Parasuk, Vudhichai; Caro, Jürgen; Assabumrungrat, Suttichai

2018-03-01

Adsorption and diffusion of an equimolar feed mixture of CO2 and CO in MIL-127 at three different temperatures and pressures up to 12 bar were investigated by molecular simulations. The adsorption was simulated using Gibbs-Ensemble Monte Carlo (GEMC). The structure of the adsorbed phase and the diffusion in the MIL were investigated using Molecular Dynamics (MD) simulations. The adsorption selectivity of MIL-127 for CO2 over CO at 233 K was about 15. When combining adsorption and diffusion selectivities, a membrane selectivity of about 12 is predicted. For higher temperatures, both adsorption and diffusion selectivity are found to be smaller.

Process and analytical studies of enhanced low severity co-processing using selective coal pretreatment

Energy Technology Data Exchange (ETDEWEB)

Baldwin, R.M.; Miller, R.L.

1991-12-01

The findings in the first phase were as follows: 1. Both reductive (non-selective) alkylation and selective oxygen alkylation brought about an increase in liquefaction reactivity for both coals. 2. Selective oxygen alkylation is more effective in enhancing the reactivity of low rank coals. In the second phase of studies, the major findings were as follows: 1. Liquefaction reactivity increases with increasing level of alkylation for both hydroliquefaction and co-processing reaction conditions. 2. the increase in reactivity found for O-alkylated Wyodak subbituminous coal is caused by chemical changes at phenolic and carboxylic functional sites. 3. O-methylation of Wyodak subbituminous coal reduced the apparent activation energy for liquefaction of this coal.

CO2 Capture Rate Sensitivity Versus Purchase of CO2 Quotas. Optimizing Investment Choice for Electricity Sector

Directory of Open Access Journals (Sweden)

Coussy Paula

2014-09-01

Full Text Available Carbon capture technology (and associated storage, applied to power plants, reduces atmospheric CO2 emissions. This article demonstrates that, in the particular case of the deployment phase of CO2 capture technology during which CO2 quota price may be low, capturing less than 90% of total CO2 emissions from power plants can be economically attractive. Indeed, for an electric power company capture technology is interesting, only if the discounted marginal cost of capture is lower than the discounted marginal cost of purchased quotas. When CO2 price is low, it is interesting to have flexibility and reduce the overall capture rate of the site, by stopping the capture system of one of the combustion trains if the site has multiple ones, or by adopting less than 90% CO2 capture rate.

SiteChar. Characterisation of European CO2 storage. Deliverable D8.1. Qualitative and quantitative social site characterisations

Energy Technology Data Exchange (ETDEWEB)

Brunsting, S.; Pol, M.; Paukovic, M. [ECN Policy Studies, Energy research Centre of the Netherlands ECN, Amsterdam (Netherlands); Kaiser, M.; Zimmer, R. [Unabhaengiges Institut fuer Umweltfragen UfU, Berlin (Germany); Shackley, S.; Mabon, L. [Scottish Carbon Capture and Storage SCCS, Edinburg, Scotland (United Kingdom); Hepplewhite, F.; Loveridge, R. [Energy Markets Unit, Scottish Government, Edinburg, Scotland (United Kingdom); Mazurowski, M.; Polak-Osiniak, D. [Polish Oil and Gas Company PGNiG, Warszawa (Poland); Rybicki, C. [AGH University of Science and Technology, Krakow (Poland)

2012-10-15

At local level, public support has proven crucial to the implementation of CO2 capture and storage (CCS) demonstration projects. Whereas no method exists to guarantee public acceptability of any project, a constructive stakeholder engagement process does increase the likelihood thereof. Social site characterisation can be used as an instrument to explore, plan and evaluate a process of active and constructive local stakeholder engagement in a prospective CCS project as a parallel activity to technical site characterisation. It roughly consists of a formative research phase to get acquainted with the area followed by a series of public information and engagement activities. This deliverable presents results from the first phase for the social site characterisations of a prospective CCS site in Poland (onshore) and the UK (offshore), using qualitative as well as quantitative research methods, as a first step to planning of local public engagement activities and evaluation of these activities that will be undertaken by this consortium at both sites in the near future. Although the term social site characterisation actually refers to the entire process of formative research and subsequent public outreach, and hence to the complete package of awareness work undertaken as part of SiteChar, in the present deliverable the term only refers to the formative research activities as undertaken up to now and as described in this deliverable. The qualitative part of the social site characterisation consisted of (1) a description of relevant social site characteristics such as local history; (2) interviews with relevant local stakeholders; (3) a media analysis of local newspapers. The quantitative part of the social site characterisation consisted of surveys using representative samples to characterise the local population in terms of awareness, knowledge and perceptions of CCS, felt involvement in decision making, extent of local activism, level of trust in representatives and

Photosynthetic responses to elevated CO2 and O3 in Quercus ilex leaves at a natural CO2 spring

International Nuclear Information System (INIS)

Paoletti, E.; Seufert, G.; Della Rocca, G.; Thomsen, H.

2007-01-01

Photosynthetic stimulation and stomatal conductance (Gs) depression in Quercus ilex leaves at a CO 2 spring suggested no down-regulation. The insensitivity of Gs to a CO 2 increase (from ambient 1500 to 2000 μmol mol -1 ) suggested stomatal acclimation. Both responses are likely adaptations to the special environment of CO 2 springs. At the CO 2 -enriched site, not at the control site, photosynthesis decreased 9% in leaves exposed to 2x ambient O 3 concentrations in branch enclosures, compared to controls in charcoal-filtered air. The stomatal density reduction at high CO 2 was one-third lower than the concomitant Gs reduction, so that the O 3 uptake per single stoma was lower than at ambient CO 2 . No significant variation in monoterpene emission was measured. Higher trichome and mesophyll density were recorded at the CO 2 -enriched site, accounting for lower O 3 sensitivity. A long-term exposure to H 2 S, reflected by higher foliar S-content, and CO 2 might depress the antioxidant capacity of leaves close to the vent and increase their O 3 sensitivity. - Very high CO 2 concentrations did not compensate for the effects of O 3 on holm oak photosynthesis

Monitoring of injected CO2 at two commercial geologic storage sites with significant pressure depletion and/or re-pressurization histories: A case study

Directory of Open Access Journals (Sweden)

Dayanand Saini

2017-03-01

The monitoring technologies that have been used/deployed/tested at both the normally pressured West Hastings and the subnormally pressured Bell Creek storage sites appear to adequately address any of the potential “out of zone migration” of injected CO2 at these sites. It would be interesting to see if any of the collected monitoring data at the West Hastings and the Bell Creek storage sites could also be used in future to better understand the viability of initially subnormally pressured and subsequently depleted and re-pressurized oil fields as secure geologic CO2 storage sites with relatively large storage CO2 capacities compared to the depleted and re-pressurized oil fields that were initially discovered as normally pressured.

Element mobilization and immobilization from carbonate rocks between CO 2 storage reservoirs and the overlying aquifers during a potential CO 2 leakage

Energy Technology Data Exchange (ETDEWEB)

Lawter, Amanda R.; Qafoku, Nikolla P.; Asmussen, R. Matthew; Kukkadapu, Ravi K.; Qafoku, Odeta; Bacon, Diana H.; Brown, Christopher F.

2018-04-01

Despite the numerous studies on changes within the reservoir following CO2 injection and the effects of CO2 release into overlying aquifers, little or no literature is available on the effect of CO2 release on rock between the storage reservoirs and subsurface. To address this knowledge gap, relevant rock materials, temperatures and pressures were used to study mineralogical and elemental changes in this intermediate zone. After rocks reacted with CO2, liquid analysis showed an increase of major elements (e.g., Ca, and Mg) and variable concentrations of potential contaminants (e.g., Sr and Ba); lower concentrations were observed in N2 controls. In experiments with As/Cd and/or organic spikes, representing potential contaminants in the CO2 plume originating in the storage reservoir, most or all of these contaminants were removed from the aqueous phase. SEM and Mössbauer spectroscopy results showed the formation of new minerals and Fe oxides in some CO2-reacted samples, indicating potential for contaminant removal through mineral incorporation or adsorption onto Fe oxides. These experiments show the interactions between the CO2-laden plume and the rock between storage reservoirs and overlying aquifers have the potential to affect the level of risk to overlying groundwater, and should be considered during site selection and risk evaluation.

Influence of pyrolysis conditions on the CO2/CH4 and O2/N2 perm selectivity of supported carbon molecular sieve membranes

International Nuclear Information System (INIS)

Mohd Fikri Abdul Rahman; Wan Mohd Hafiz Faizal Wan Harun; Mohd Azmier Ahmad

2010-01-01

This work focused on the effect of pyrolysis conditions onto supported carbon molecular sieve membranes performance in pure gas permeation and perm selectivity. The membrane support was synthesis by carbonization of titania mixed with cellulose acetate at temperature of 125 degree Celsius. The molecular sieving membrane layer was obtained by coating the polyvinyl alcohol-glutaraldehyde solution onto the membrane support before heated at various pyrolysis temperatures and holding times. The optimum preparation conditions were found at pyrolysis temperature and holding time of 400 degree Celsius and 30 minutes, respectively. At this point, the CO 2 and O 2 permeation flux were 2.63 ml/ min and 2.67 ml/ min, respectively. Meanwhile, the perm selectivities of CO 2 / CH 4 and O 2 / N 2 were 1.87 and 1.92, respectively. (author)

Selective Reduction of CO2 to CH4 by Tandem Hydrosilylation with Mixed Al/B Catalysts

KAUST Repository

Chen, Jiawei

2016-04-04

This contribution reports the first example of highly selective reduction of CO2 into CH4 via tandem hydrosilylation with mixed main-group organo-Lewis acid (LA) catalysts [Al(C6F5)3 + B(C6F5)3] {[Al] + [B]}. As shown by this comprehensive experimental and computational study, in this unique tandem catalytic process, [Al] effectively mediates the first step of the overall reduction cycle, namely the fixation of CO2 into HCOOSiEt3 (1) via the LA-mediated C=O activation, while [B] is incapable of promoting the same transformation. On the other hand, [B] is shown to be an excellent catalyst for the subsequent reduction steps 2–4, namely the hydrosilylation of the more basic intermediates [1 to H2C(OSiEt3)2 (2) to H3COSiEt3 (3) and finally to CH4] through the frustrated-Lewis-pair (FLP)-type Si–H activation. Hence, with the required combination of [Al] and [B], a highly selective hydrosilylative reduction of CO2 system has been developed, achieving high CH4 production yield up to 94%. The remarkably different catalytic behaviors between [Al] and [B] are attributed to the higher overall Lewis acidity of [Al] derived from two conflicting factors (electronic and steric effects), which renders the higher tendency of [Al] to form stable [Al]–substrate (intermediate) adducts with CO2 as well as subsequent intermediates 1, 2 and 3. Overall, the roles of [Al] and [B] are not only complementary but also synergistic in the total reduction of CO2, which render both [Al]-mediated first reduction step and [B]-mediated subsequent steps catalytic.

Selective Reduction of CO2 to CH4 by Tandem Hydrosilylation with Mixed Al/B Catalysts

KAUST Repository

Chen, Jiawei; Falivene, Laura; Caporaso, Lucia; Cavallo, Luigi; Chen, Eugene Y.-X.

2016-01-01

This contribution reports the first example of highly selective reduction of CO2 into CH4 via tandem hydrosilylation with mixed main-group organo-Lewis acid (LA) catalysts [Al(C6F5)3 + B(C6F5)3] {[Al] + [B]}. As shown by this comprehensive experimental and computational study, in this unique tandem catalytic process, [Al] effectively mediates the first step of the overall reduction cycle, namely the fixation of CO2 into HCOOSiEt3 (1) via the LA-mediated C=O activation, while [B] is incapable of promoting the same transformation. On the other hand, [B] is shown to be an excellent catalyst for the subsequent reduction steps 2–4, namely the hydrosilylation of the more basic intermediates [1 to H2C(OSiEt3)2 (2) to H3COSiEt3 (3) and finally to CH4] through the frustrated-Lewis-pair (FLP)-type Si–H activation. Hence, with the required combination of [Al] and [B], a highly selective hydrosilylative reduction of CO2 system has been developed, achieving high CH4 production yield up to 94%. The remarkably different catalytic behaviors between [Al] and [B] are attributed to the higher overall Lewis acidity of [Al] derived from two conflicting factors (electronic and steric effects), which renders the higher tendency of [Al] to form stable [Al]–substrate (intermediate) adducts with CO2 as well as subsequent intermediates 1, 2 and 3. Overall, the roles of [Al] and [B] are not only complementary but also synergistic in the total reduction of CO2, which render both [Al]-mediated first reduction step and [B]-mediated subsequent steps catalytic.

Comparison of CO₂ Detection Methods Tested in Shallow Groundwater Monitoring Wells at a Geological Sequestration Site

Energy Technology Data Exchange (ETDEWEB)

Edenborn, Harry M.; Jain, Jinesh N.

2016-05-17

The geological storage of anthropogenic carbon dioxide (CO₂) is one method of reducing the amount of CO₂ released into the atmosphere. Monitoring programs typically determine baseline conditions in surface and near-surface environments before, during, and after CO₂ injection to evaluate if impacts related to injection have occurred. Because CO₂ concentrations in groundwater fluctuate naturally due to complex geochemical and geomicrobiologicalinteractions, a clear understanding of the baseline behavior of CO₂ in groundwater near injection sites is important. Numerous ways of measuring aqueous CO₂ in the field and lab are currently used, but most methods have significant shortcomings (e.g., are tedious, lengthy, have interferences, or have significant lag time before a result is determined). In this study, we examined the effectiveness of two novel CO₂ detection methods and their ability to rapidly detect CO2in shallow groundwater monitoring wells associated with the Illinois Basin –Decatur Project geological sequestration site. The CarboQC beverage carbonation meter was used to measure the concentration of CO₂ in water by monitoring temperature and pressure changes and calculating the PCO₂ from the ideal gas law. Additionally, a non-dispersive infrared (NDIR) CO< sub>2sensor enclosed in a gas-permeable, water-impermeable membrane measured CO2by determining an equilibrium concentration. Results showed that the CarboQC method provided rapid (< 3 min) and repeatable results under field conditions within a measured concentration range of 15 –125 mg/L CO₂. The NDIR sensor results correlated well (r²= 0.93) with the CarboQC data, but CO₂ equilibration required at least 15 minutes, making the method somewhat less desirable under field conditions. In contrast, NDIR-based sensors have a greater potential for long-term deployment. Both

Assessing reservoir performance risk in CO{sub 2} storage projects

Energy Technology Data Exchange (ETDEWEB)

Bowden, A.R. [URS Corp., San Francisco, CA (United States); Rigg, A. [CRC for Greenhouse Gas Technologies, Canberra (Australia)

2005-07-01

One of the main issues for researchers involved with geological storage of carbon dioxide (CO{sub 2}) has been the development of a proper methodology to assess and compare alternative CO{sub 2} injection projects on the basis of risk. Consideration needs to be given to technical aspects, such as the risk of leakage and the effectiveness of the intended reservoir, as well as less tangible aspects such as the value and safety of geological storage of CO{sub 2}, and potential impacts on the community and environment. The Geological Disposal of Carbon Dioxide (GEODISC), was a research program of the Australian Petroleum Cooperative Research Centre which identified 56 potential environmentally sustainable sites for CO{sub 2} injection (ESSCIs) within Australia. Several studies were carried out, involving detailed evaluation of the suitability of 4 selected sites, including Dongara, Petrel, Gippsland and Carnarvon. The GEODISC program included a risk assessment research module which required a complete and quantified risk assessment of CO{sub 2} injection as a storage option. Primary goals were to assess the risk of leakage, to assess the effectiveness of the intended reservoir, and to assess negative consequences to facilitate comparison of alternative sites. This paper discussed the background and risk assessment model. Key performance indicators (KPIs) were also developed to address the purpose of risk assessment. It was concluded that the RISQUE method is an appropriate approach and that potential injection projects can be measured against six KPIs including containment; effectiveness; self-funding potential; wider community benefits; community safety and community amenity. 6 refs., 3 tabs., 3 figs.

Hydrogen selective membrane for the natural gas system. Development of CO{sub 2}-selective biogas membrane. Final report

Energy Technology Data Exchange (ETDEWEB)

Vestboe, A.P.

2012-02-15

The project started as a literature study and technology development project for a hydrogen selective membrane for the natural gas system. The introduction of hydrogen (for example produced from wind turbines by surplus electricity) in the gas system makes it possible to store energy which can be selectively used with high energy conversion in fuel cells directly located at the end users. In order to make this possible, it is necessary to have a separating unit that can selectively remove hydrogen from the gas mixture and deliver it as fuel to the electrical generator (a fuel cell). In the project, several existing technologies were evaluated with regard to the application in view. It was concluded that while other technologies are ripe, they are costly in energy and unsuitable for the relatively low capacity application that are in question close to the end users. Membrane technology was evaluated to be the most suitable, although the technology is still under development in many cases. In the project it was found that metallic membranes in the form of palladium coated stainless discs would answer the needs for the high purity needed. Laboratory development yielded discs that could separate hydrogen from natural gas, however, the flux was low compared to the needs of the application. It was found that at least 2 bar pressure difference of hydrogen would be needed to get a high enough flux. The way to achieve this pressure would necessitate a compressor which would consume an energy amount high enough to invalidate the concept. When concluding on the results and the study it was found that the direction of the project could be changed towards developing CO{sub 2}-selective membranes with the goal of developing membrane technology that could upgrade biogas by removing CO{sub 2}. The laboratory equipment and setup that were developed in the first part of the project could be used directly in this second part of the project. In this second part of the project it was

Biofunctionalized conductive polymers enable efficient CO2 electroreduction

Science.gov (United States)

Coskun, Halime; Aljabour, Abdalaziz; De Luna, Phil; Farka, Dominik; Greunz, Theresia; Stifter, David; Kus, Mahmut; Zheng, Xueli; Liu, Min; Hassel, Achim W.; Schöfberger, Wolfgang; Sargent, Edward H.; Sariciftci, Niyazi Serdar; Stadler, Philipp

2017-01-01

Selective electrocatalysts are urgently needed for carbon dioxide (CO2) reduction to replace fossil fuels with renewable fuels, thereby closing the carbon cycle. To date, noble metals have achieved the best performance in energy yield and faradaic efficiency and have recently reached impressive electrical-to-chemical power conversion efficiencies. However, the scarcity of precious metals makes the search for scalable, metal-free, CO2 reduction reaction (CO2RR) catalysts all the more important. We report an all-organic, that is, metal-free, electrocatalyst that achieves impressive performance comparable to that of best-in-class Ag electrocatalysts. We hypothesized that polydopamine—a conjugated polymer whose structure incorporates hydrogen-bonded motifs found in enzymes—could offer the combination of efficient electrical conduction, together with rendered active catalytic sites, and potentially thereby enable CO2RR. Only by developing a vapor-phase polymerization of polydopamine were we able to combine the needed excellent conductivity with thin film–based processing. We achieve catalytic performance with geometric current densities of 18 mA cm−2 at 0.21 V overpotential (−0.86 V versus normal hydrogen electrode) for the electrosynthesis of C1 species (carbon monoxide and formate) with continuous 16-hour operation at >80% faradaic efficiency. Our catalyst exhibits lower overpotentials than state-of-the-art formate-selective metal electrocatalysts (for example, 0.5 V for Ag at 18 mA cm−1). The results confirm the value of exploiting hydrogen-bonded sequences as effective catalytic centers for renewable and cost-efficient industrial CO2RR applications. PMID:28798958

BOREAS TGB-3 CH4 and CO2 Chamber Flux Data over NSA Upland Sites

Science.gov (United States)

Savage, Kathleen; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor); Moore, Tim R.

2000-01-01

The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB-3) team collected methane and carbon dioxide (CH4, CO2) chamber flux measurements at the Northern Study Area (NSA) Fen, Old Black Spruce (OBS), Young Jack Pine (YJP), and auxiliary sites along Gillam Road and the 1989 burn site. Gas samples were extracted from chambers and analyzed at the NSA lab facility approximately every 7 days during May to September 1994 and June to October 1996. The data are provided in tabular ASCII files.

One-Pot Synthesis of Cu-Nanocluster-Decorated Brookite TiO2 Quasi-Nanocubes for Enhanced Activity and Selectivity of CO2 Photoreduction to CH4.

Science.gov (United States)

Jin, Jingpeng; Luo, Jiang; Zan, Ling; Peng, Tianyou

2017-11-17

A new kind of metallic Cu-loaded brookite TiO 2 composite, in which Cu nanoclusters with a small size of 1-3 nm are decorated on brookite TiO 2 quasi nanocube (BTN) surfaces (hereafter referred to as Cu-BTN), is synthesized via a one-pot hydrothermal process and then used as photocatalyst for CO 2 reduction. It was found that the decoration of Cu nanoclusters on BTN surfaces can improve the activity and selectivity of CO 2 photoreduction to CH 4 , and 1.5 % Cu-BTN gives a maximum overall photocatalytic activity (150.9 μmol g -1  h -1 ) for CO/CH 4 production, which is ≈11.4 and ≈3.3 times higher than those of pristine BTN (13.2 μmol g -1  h -1 ) and Ag-BTN (45.2 μmol g -1  h -1 ). Moreover, the resultant Cu-BTN products can promote the selective generation of CH 4 as compared to CO due to the number of surface oxygen vacancies and the CO 2 /H 2 O adsorption behavior, which differs from that of the pristine BTN. The present results demonstrate that brookite TiO 2 would be a potential effective photocatalyst for CO 2 photoreduction, and that Cu nanoclusters can act as an inexpensive and efficient co-catalyst alternative to the commonly used noble metals to improve the photoactivity and selectivity for CO 2 reduction to CH 4 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

In-operando elucidation of bimetallic CoNi nanoparticles during high-temperature CH 4 /CO 2 reaction

KAUST Repository

Al-Sabban, Bedour

2017-05-02

Dry reforming of methane (DRM) proceeds via CH4 decomposition to leave surface carbon species, followed by their removal with CO2-derived species. Reactivity tuning for stoichiometric CH4/CO2 reactants was attempted by alloying the non-noble metals Co and Ni, which have high affinity with CO2 and high activity for CH4 decomposition, respectively. This study was focused on providing evidence of the capturing surface coverage of the reactive intermediates and the associated structural changes of the metals during DRM at high temperature using in-operando X-ray absorption spectroscopy (XAS). On the Co catalysts, the first-order effects with respect to CH4 pressure and negative-order effects with respect to CO2 pressure on the DRM rate are consistent with the competitive adsorption of the surface oxygen species on the same sites as the CH4 decomposition reaction. The Ni surface provides comparatively higher rates of CH4 decomposition and the resultant DRM than the Co catalyst but leaves some deposited carbon on the catalyst surface. In contrast, the bimetallic CoNi catalyst exhibits reactivity towards the DRM but with kinetic orders resembling Co catalyst, producing negligible carbon deposition by balancing CH4 and CO2 activation. The in-operando X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) measurements confirmed that the Co catalyst was progressively oxidized from the surface to the bulk with reaction time, whereas CoNi and Ni remained relatively reduced during DRM. Density functional theory (DFT) calculation considering the high reaction temperature for DRM confirmed the unselective site arrangement between Co and Ni atoms in both the surface and bulk of the alloy nanoparticle (NP). The calculated heat of oxygen chemisorption became more exothermic in the order of Ni, CoNi, Co, consistent with the catalytic behavior. The comprehensive experimental and theoretical evidence provided herein clearly suggests

Selective removal of Cs and Re by precipitation in a Na2CO3-H2O2 solution

International Nuclear Information System (INIS)

Eil-Hee Lee; Jae-Gwan Lim; Dong-Yong Chung; Han-Beom Yang; Kwang-Wook Kim

2010-01-01

The removal of Cs and Re (as a surrogate for Tc) by selective precipitation from the simulated fission products which were co-dissolved with uranium during the oxidative dissolution of spent fuel in a Na 2 CO 3 -H 2 O 2 solution was investigated in this study. The precipitations of Cs and Re were examined by introducing sodium tetraphenylborate (NaTPB) and tetraphenylohosponium chloride (TPPCl), respectively. The precipitation of Cs by NaTPB and that of Re by TPPCl each took place within 5 min, and an increase in temperature up to 50 deg C and a stirring speed up to 1000 rpm hardly affected their precipitation rates. The most important factor in the precipitation with NaTPB and TPPCl was found to be a pH of the solution after precipitation. Since Mo tends to co-precipitate with Cs or Re at a lower pH, an effective precipitation with NaTPB and TPPCl was done at pH of above 9 without the co-precipitation of Mo. More than 99% of Cs and Re were precipitated when the initial concentration ratio of NaTPB to Cs was above 1 and when that of TPPCl to Re was above 1. The precipitation of Cs and Re was never affected by the concentration of Na 2 CO 3 and H 2 O 2 , even though they were raised up to 1.5 and 1.0 M, respectively. Precipitation yields of Cs and Re in a Na 2 CO 3 -H 2 O 2 solution were found to be dependent on the concentration ratios of [NaTBP]/[Cs] and [TPPCl]/[Re]. (author)

Site selection under the underground geologic store plan. Procedures of selecting underground geologic stores as disputed by society, science, and politics. Site selection rules

International Nuclear Information System (INIS)

Aebersold, M.

2008-01-01

The new Nuclear Power Act and the Nuclear Power Ordinance of 2005 are used in Switzerland to select a site of an underground geologic store for radioactive waste in a substantive planning procedure. The ''Underground Geologic Store Substantive Plan'' is to ensure the possibility to build underground geologic stores in an independent, transparent and fair procedure. The Federal Office for Energy (BFE) is the agency responsible for this procedure. The ''Underground Geologic Store'' Substantive Plan comprises these principles: - The long term protection of people and the environment enjoys priority. Aspects of regional planning, economics and society are of secondary importance. - Site selection is based on the waste volumes arising from the five nuclear power plants currently existing in Switzerland. The Substantive Plan is no precedent for or against future nuclear power plants. - A transparent and fair procedure is an indispensable prerequisite for achieving the objectives of a Substantive Plan, i.e., finding accepted sites for underground geologic stores. The Underground Geologic Stores Substantive Plan is arranged in two parts, a conceptual part defining the rules of the selection process, and an implementation part documenting the selection process step by step and, in the end, naming specific sites of underground geologic stores in Switzerland. The objective is to be able to commission underground geologic stores in 25 or 35 years' time. In principle, 2 sites are envisaged, one for low and intermediate level waste, and one for high level waste. The Swiss Federal Council approved the conceptual part on April 2, 2008. This marks the beginning of the implementation phase and the site selection process proper. (orig.)

Site-selective 13C labeling of proteins using erythrose

International Nuclear Information System (INIS)

Weininger, Ulrich

2017-01-01

NMR-spectroscopy enables unique experimental studies on protein dynamics at atomic resolution. In order to obtain a full atom view on protein dynamics, and to study specific local processes like ring-flips, proton-transfer, or tautomerization, one has to perform studies on amino-acid side chains. A key requirement for these studies is site-selective labeling with 13 C and/or 1 H, which is achieved in the most general way by using site-selectively 13 C-enriched glucose (1- and 2- 13 C) as the carbon source in bacterial expression systems. Using this strategy, multiple sites in side chains, including aromatics, become site-selectively labeled and suitable for relaxation studies. Here we systematically investigate the use of site-selectively 13 C-enriched erythrose (1-, 2-, 3- and 4- 13 C) as a suitable precursor for 13 C labeled aromatic side chains. We quantify 13 C incorporation in nearly all sites in all 20 amino acids and compare the results to glucose based labeling. In general the erythrose approach results in more selective labeling. While there is only a minor gain for phenylalanine and tyrosine side-chains, the 13 C incorporation level for tryptophan is at least doubled. Additionally, the Phe ζ and Trp η2 positions become labeled. In the aliphatic side chains, labeling using erythrose yields isolated 13 C labels for certain positions, like Ile β and His β, making these sites suitable for dynamics studies. Using erythrose instead of glucose as a source for site-selective 13 C labeling enables unique or superior labeling for certain positions and is thereby expanding the toolbox for customized isotope labeling of amino-acid side-chains.

Selective detection of Cu2 + and Co2 + in aqueous media: Asymmetric chemosensors, crystal structure and spectroscopic studies

Science.gov (United States)

Dogaheh, Samira Gholizadeh; Khanmohammadi, Hamid; Carolina Sañudo, E.

2017-05-01

Two new azo-azomethine receptors, H2L1 and H2L2, containing hydrazine, naphthalene and different electron withdrawing groups, Cl and NO2, have been designed and synthesized for qualitative and quantitative detection of Cu2 + and Co2 + in aqueous media. The crystal structure of H2L1is reported. The H2L1was used as a chemosensor for selective detection of trace amount of Cu2 + in aqueous media. H2L2 was also applied to naked-eye distinction of Cu2 + and Co2 + from other transition metal ions in aqueous media. Detection limit of Cu2 + is 1.13 μM and 1.26 μM, in water, for H2L1 and H2L2, respectively, which are lower than the World Health Organization (WHO) recommended level. The binuclear Cu2 + and Co2 + complexes of the receptors have been also prepared and characterized using spectroscopic methods and MALDI-TOF mass analysis. Furthermore, the binding stoichiometry between the receptors upon the addition Cu2 + and Co2 + has been investigated using Job's plot. Moreover, the fluorescence emission spectra of the receptors and their metal complexes are also reported.

Modeling CO2 Storage in Fractured Reservoirs: Fracture-Matrix Interactions of Free-Phase and Dissolved CO2

Science.gov (United States)

Oldenburg, C. M.; Zhou, Q.; Birkholzer, J. T.

2017-12-01

The injection of supercritical CO2 (scCO2) in fractured reservoirs has been conducted at several storage sites. However, no site-specific dual-continuum modeling for fractured reservoirs has been reported and modeling studies have generally underestimated the fracture-matrix interactions. We developed a conceptual model for enhanced CO2 storage to take into account global scCO2 migration in the fracture continuum, local storage of scCO2 and dissolved CO2 (dsCO2) in the matrix continuum, and driving forces for scCO2 invasion and dsCO2 diffusion from fractures. High-resolution discrete fracture-matrix models were developed for a column of idealized matrix blocks bounded by vertical and horizontal fractures and for a km-scale fractured reservoir. The column-scale simulation results show that equilibrium storage efficiency strongly depends on matrix entry capillary pressure and matrix-matrix connectivity while the time scale to reach equilibrium is sensitive to fracture spacing and matrix flow properties. The reservoir-scale modeling results shows that the preferential migration of scCO2 through fractures is coupled with bulk storage in the rock matrix that in turn retards the fracture scCO2 plume. We also developed unified-form diffusive flux equations to account for dsCO2 storage in brine-filled matrix blocks and found solubility trapping is significant in fractured reservoirs with low-permeability matrix.

Size effect on the adsorption and dissociation of CO{sub 2} on Co nanoclusters

Energy Technology Data Exchange (ETDEWEB)

Yu, Haiyan; Cao, Dapeng; Fisher, Adrian [International Research Center for Soft Matter, State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Johnston, Roy L. [School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Cheng, Daojian, E-mail: chengdj@mail.buct.edu.cn [International Research Center for Soft Matter, State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China)

2017-02-28

Highlights: • Co{sub 13}, Co{sub 38} and Co{sub 55} nanoclusters were predicted as the high-symmetry structures. • CO{sub 2} dissociation on the size-selected Co{sub 13}, Co{sub 38} and Co{sub 55} nanoclusters was studied. • Co{sub 55} nanocluster possesses the highest activity relevant to CO{sub 2} dissociation. • A non-monotonous behavior of the dissociation barrier of CO{sub 2} with the size was found. - Abstract: Spin-polarized density functional theory calculations were carried out to study the adsorption and dissociation properties of CO{sub 2} on size-selected Co{sub 13}, Co{sub 38} and Co{sub 55} nanoclusters. Based on genetic algorithm method, Co{sub 13}, Co{sub 38} and Co{sub 55} nanoclusters were predicted as the most stable high-symmetry structures among these Co{sub n} (n = 2–58) nanoclusters from the Gupta potential. For the adsorption of CO{sub 2}, CO and O on size-selected Co{sub 13}, Co{sub 38} and Co{sub 55} nanoclusters, the lowest adsorption strength is found for all the different adsorbates on Co{sub 55} nanocluster. For the dissociation of CO{sub 2} on these size-selected Co nanoclusters, the largest Co{sub 55} nanocluster possesses the greatest catalytic activity for the dissociation of CO{sub 2}, with the smallest reaction barrier of 0.38 eV. Our results reveal a non-monotonous behavior of the catalytic activities of Co nanoclusters on size, which is of fundamental interest for the design of new Co catalysts for the conversion of CO{sub 2}.

Assessment of CO2 Mineralization and Dynamic Rock Properties at the Kemper Pilot CO2 Injection Site

Science.gov (United States)

Qin, F.; Kirkland, B. L.; Beckingham, L. E.

2017-12-01

CO2-brine-mineral reactions following CO2 injection may impact rock properties including porosity, permeability, and pore connectivity. The rate and extent of alteration largely depends on the nature and evolution of reactive mineral interfaces. In this work, the potential for geochemical reactions and the nature of the reactive mineral interface and corresponding hydrologic properties are evaluated for samples from the Lower Tuscaloosa, Washita-Fredericksburg, and Paluxy formations. These formations have been identified as future regionally extensive and attractive CO2 storage reservoirs at the CO2 Storage Complex in Kemper County, Mississippi, USA (Project ECO2S). Samples from these formations were obtained from the Geological Survey of Alabama and evaluated using a suite of complementary analyses. The mineral composition of these samples will be determined using petrography and powder X-ray Diffraction (XRD). Using these compositions, continuum-scale reactive transport simulations will be developed and the potential CO2-brine-mineral interactions will be examined. Simulations will focus on identifying potential reactive minerals as well as the corresponding rate and extent of reactions. The spatial distribution and accessibility of minerals to reactive fluids is critical to understanding mineral reaction rates and corresponding changes in the pore structure, including pore connectivity, porosity and permeability. The nature of the pore-mineral interface, and distribution of reactive minerals, will be determined through imaging analysis. Multiple 2D scanning electron microscopy (SEM) backscattered electron (BSE) images and energy dispersive x-ray spectroscopy (EDS) images will be used to create spatial maps of mineral distributions. These maps will be processed to evaluate the accessibility of reactive minerals and the potential for flow-path modifications following CO2 injection. The "Establishing an Early CO2 Storage Complex in Kemper, MS" project is funded by

Plant–plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2: an experiment with plant populations from naturally high CO2 areas

Science.gov (United States)

van Loon, Marloes P.; Rietkerk, Max; Dekker, Stefan C.; Hikosaka, Kouki; Ueda, Miki U.; Anten, Niels P. R.

2016-01-01

Background and Aims The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant–plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may benefit more from [CO2] elevation than others. The relative contribution of plastic (within the plant’s lifetime) and genotypic (over several generations) responses to elevated [CO2] on plant performance was investigated and how these patterns are modified by plant–plant interactions was analysed. Methods Plantago asiatica seeds originating from natural CO2 springs and from ambient [CO2] sites were grown in mono stands of each one of the two origins as well as mixtures of both origins. In total, 1944 plants were grown in [CO2]-controlled walk-in climate rooms, under a [CO2] of 270, 450 and 750 ppm. A model was used for upscaling from leaf to whole-plant photosynthesis and for quantifying the influence of plastic and genotypic responses. Key Results It was shown that changes in canopy photosynthesis, specific leaf area (SLA) and stomatal conductance in response to changes in growth [CO2] were mainly determined by plastic and not by genotypic responses. We further found that plants originating from high [CO2] habitats performed better in terms of whole-plant photosynthesis, biomass and leaf area, than those from ambient [CO2] habitats at elevated [CO2] only when both genotypes competed. Similarly, plants from ambient [CO2] habitats performed better at low [CO2], also only when both genotypes competed. No difference in performance was found in mono stands. Conclusion The results indicate that natural selection under increasing [CO2] will be mainly driven by competitive interactions. This supports the notion that plant–plant interactions have an important influence on future vegetation functioning and species distribution. Furthermore, plant performance was mainly

Geochemical modelling of CO2-water-rock interactions for carbon storage : data requirements and outputs

International Nuclear Information System (INIS)

Kirste, D.

2008-01-01

A geochemical model was used to predict the short-term and long-term behaviour of carbon dioxide (CO 2 ), formation water, and reservoir mineralogy at a carbon sequestration site. Data requirements for the geochemical model included detailed mineral petrography; formation water chemistry; thermodynamic and kinetic data for mineral phases; and rock and reservoir physical characteristics. The model was used to determine the types of outputs expected for potential CO 2 storage sites and natural analogues. Reaction path modelling was conducted to determine the total reactivity or CO 2 storage capability of the rock by applying static equilibrium and kinetic simulations. Potential product phases were identified using the modelling technique, which also enabled the identification of the chemical evolution of the system. Results of the modelling study demonstrated that changes in porosity and permeability over time should be considered during the site selection process.

Role of the adsorbed oxygen species in the selective electrochemical reduction of CO_2 to alcohols and carbonyls on copper electrodes

International Nuclear Information System (INIS)

Le Duff, Cecile S.; Lawrence, Matthew J.; Rodriguez, Paramaconi

2017-01-01

The electrochemical reduction of CO_2 into fuels has gained significant attention recently as source of renewable carbon-based fuels. The unique high selectivity of copper in the electrochemical reduction of CO_2 to hydrocarbons has called much interest in discovering its mechanism. In order to provide significant information about the role of oxygen in the electrochemical reduction of CO_2 on Cu electrodes, the conditions of the surface structure and the composition of the Cu single crystal electrodes were controlled over time. This was achieved using pulsed voltammetry, since the pulse sequence can be programmed to guarantee reproducible initial conditions for the reaction at every fraction of time and at a given frequency. In contrast to the selectivity of CO_2 reduction using cyclic voltammetry and chronoamperometric methods, a large selection of oxygenated hydrocarbons was found under alternating voltage conditions. Product selectivity towards the formation of oxygenated hydrocarbon was associated to the coverage of oxygen species, which is surface-structure- and potential-dependent. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

[BMIM][PF6] Incorporation Doubles CO2 Selectivity of ZIF-8: Elucidation of Interactions and Their Consequences on Performance.

Science.gov (United States)

Kinik, F Pelin; Altintas, Cigdem; Balci, Volkan; Koyuturk, Burak; Uzun, Alper; Keskin, Seda

2016-11-16

Experiments were combined with atomically detailed simulations and density functional theory (DFT) calculations to understand the effect of incorporation of an ionic liquid (IL), 1-n-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF 6 ]), into a metal organic framework (MOF with a zeolitic imidazolate framework), ZIF-8, on the CO 2 separation performance. The interactions between [BMIM][PF 6 ] and ZIF-8 were examined in deep detail, and their consequences on CO 2 /CH 4 , CO 2 /N 2 , and CH 4 /N 2 separation have been elucidated by using experimental measurements complemented by DFT calculations and atomically detailed simulations. Results suggest that IL-MOF interactions strongly affect the gas affinity of materials at low pressure, whereas available pore volume plays a key role for gas adsorption at high pressures. Direct interactions between IL and MOF lead to at least a doubling of CO 2 /CH 4 and CO 2 /N 2 selectivities of ZIF-8. These results provide opportunities for rational design and development of IL-incorporated MOFs with exceptional selectivity for target gas separation applications.

Systematic modulation and enhancement of CO{sub 2} : N{sub 2} selectivity and water stability in an isoreticular series of bio-MOF-11 analogues

Energy Technology Data Exchange (ETDEWEB)

Li, Tao; Chen, De-Li; Sullivan, Jeanne E.; Kozlowski, Mark T.; Johnson, J Karl; Rosi, Nathaniel L.

2013-02-01

An isoreticular series of cobalt-adeninate bio-MOFs (bio-MOFs 11-14) is reported. The pores of bio-MOFs 11-14 are decorated with acetate, propionate, butyrate, and valerate, respectively. The nitrogen (N{sub 2}) and carbon dioxide (CO{sub 2}) adsorption properties of these materials are studied and compared. The isosteric heats of adsorption for CO{sub 2} are calculated, and the CO{sub 2}:N{sub 2} selectivities for each material are 10 determined. As the lengths of the aliphatic chains decorating the pores in bio-MOFs 11-14 increase, the BET surface areas decrease from 1148 m{sup 2}/g to 17 m{sup 2}/g while the CO{sub 2}:N{sub 2} selectivities predicted from ideal adsorbed solution theory at 1 bar and 273 K for a 10:90 CO{sub 2}:N{sub 2} mixture range from 73:1 for bio-MOF-11 to 123:1 for bio-MOF-12 and finally to 107:1 for bio-MOF-13. At 298 K, the selectivities are 43:1 for bio-MOF-11, 52:1 for bio-MOF-12, and 40:1 for bio-MOF-13. Additionally, it is shown that 15 bio-MOF-14 exhibits a unique molecular sieving property that allows it to adsorb CO{sub 2} but not N{sub 2} at 273 and 298 K. Finally, the water stability of bio-MOFs 11-14 increases with increasing aliphatic chain length. Bio-MOF-14 exhibits no loss of crystallinity or porosity after soaking in water for one month.

A rod-packing microporous hydrogen-bonded organic framework for highly selective separation of C2H2/CO2at room temperature

KAUST Repository

Li, Peng

2014-11-13

Self-assembly of a trigonal building subunit with diaminotriazines (DAT) functional groups leads to a unique rod-packing 3D microporous hydrogen-bonded organic framework (HOF-3). This material shows permanent porosity and demonstrates highly selective separation of C2H2/CO2 at ambient temperature and pressure.

A rod-packing microporous hydrogen-bonded organic framework for highly selective separation of C2H2/CO2at room temperature

KAUST Repository

Li, Peng; He, Yabing; Zhao, Yunfeng; Weng, Linhong; Wang, Hailong; Krishna, Rajamani A A; Wu, Hui; Zhou, Wei; O'Keeffe, Michael A.; Han, Yu; Chen, Banglin

2014-01-01

Self-assembly of a trigonal building subunit with diaminotriazines (DAT) functional groups leads to a unique rod-packing 3D microporous hydrogen-bonded organic framework (HOF-3). This material shows permanent porosity and demonstrates highly selective separation of C2H2/CO2 at ambient temperature and pressure.

The potential of near-surface geophysical methods in a hierarchical monitoring approach for the detection of shallow CO2 seeps at geological storage sites

Science.gov (United States)

Sauer, U.; Schuetze, C.; Dietrich, P.

2013-12-01

The MONACO project (Monitoring approach for geological CO2 storage sites using a hierarchic observation concept) aims to find reliable monitoring tools that work on different spatial and temporal scales at geological CO2 storage sites. This integrative hierarchical monitoring approach based on different levels of coverage and resolutions is proposed as a means of reliably detecting CO2 degassing areas at ground surface level and for identifying CO2 leakages from storage formations into the shallow subsurface, as well as CO2 releases into the atmosphere. As part of this integrative hierarchical monitoring concept, several methods and technologies from ground-based remote sensing (Open-path Fourier-transform infrared (OP-FTIR) spectroscopy), regional measurements (near-surface geophysics, chamber-based soil CO2 flux measurement) and local in-situ measurements (using shallow boreholes) will either be combined or used complementary to one another. The proposed combination is a suitable concept for investigating CO2 release sites. This also presents the possibility of adopting a modular monitoring concept whereby our monitoring approach can be expanded to incorporate other methods in various coverage scales at any temporal resolution. The link between information obtained from large-scale surveys and local in-situ monitoring can be realized by sufficient geophysical techniques for meso-scale monitoring, such as geoelectrical and self-potential (SP) surveys. These methods are useful for characterizing fluid flow and transport processes in permeable near-surface sedimentary layers and can yield important information concerning CO2-affected subsurface structures. Results of measurements carried out a natural analogue site in the Czech Republic indicate that the hierarchical monitoring approach represents a successful multidisciplinary modular concept that can be used to monitor both physical and chemical processes taking place during CO2 migration and seepage. The

A Geochemical Approach for Monitoring a CO2 Pilot Site: Rousse, France. A Major gases, CO2-Carbon Isotopes and Noble Gases Combined Approach Une méthode géochimique pour la surveillance d’un site pilote de stockage de CO2 : Rousse, France. Approche combinant les gaz majeurs, l’isotopie du carbone du CO2 et les gaz rares

Directory of Open Access Journals (Sweden)

Garcia B.

2012-02-01

storage pilot suggest that noble gas compositions produced by oxyfuel process are sufficiently exotic compared to compositions found in nature (reservoir, aquifer and air to be directly used as tracers of the injected CO2, and to detect and quantify leaks at soil and aquifer levels. Ce papier presente la caracterisation geochimique des differents gaz, naturels et anthropogeniques, impliques dans un pilote de stockage de CO2 en champ de gaz naturel appauvri (Rousse, France. Dans ce pilote, le CO2 est produit par oxycombustion d’un gaz naturel transforme en gaz domestique a l’usine de Lacq. Ce CO2 est transporte dans un pipeline de 30 km de longueur jusqu’au reservoir de gaz appauvri de Rousse. Les gaz produits a Rousse avant injection de CO2, le gaz commercial de Lacq et le CO2 resultant de l’oxycombustion ont ete echantillonnes, ainsi que les gaz situes dans un puits de surveillance (a une profondeur de 45 m et les gaz du sol situes au voisinage de Rousse. Pour tous ces echantillons, la composition en gaz majeurs, la signature isotopique du carbone ainsi que l’abondance et signature isotopique des gaz rares ont ete determinees. Les compositions gazeuses du gaz naturel de Rousse sont comparables a celle du gaz domestique de Lacq avec le methane comme compose principal et la fraction C2-C5 et CO2 comme gaz residuels. Les gaz des sols refletent typiquement des melanges entre l’air (pole pur et le CO2 d’origine biogenique (avec des teneurs maximales de l’ordre de 9-10 %, tandis que les gaz presents dans le puits de monitoring refletent typiquement la composition de l’air sans exces de CO2. Le gaz de Rousse et le gaz domestique du site de Lacq ont une composition isotopique δ13CCH4 egale a –41,0 ‰ et –43,0 ‰ respectivement. Le CO2 injecte sur Rousse a une composition isotopique δ13CCO2 egale a –40,0 ‰ a la sortie de la chambre d’oxycombustion, tandis que la composition isotopique δ13CCO2 des gaz des sols est comprise entre –15 et –25 �

Preliminary reactive geochemical transport simulation study on CO2 geological sequestration at the Changhua Coastal Industrial Park Site, Taiwan

Science.gov (United States)

Sung, R.; Li, M.

2013-12-01

Mineral trapping by precipitated carbonate minerals is one of critical mechanisms for successful long-term geological sequestration (CGS) in deep saline aquifer. Aquifer acidification induced by the increase of carbonic acid (H2CO3) and bicarbonate ions (HCO3-) as the dissolution of injected CO2 may induce the dissolution of minerals and hinder the effectiveness of cap rock causing potential risk of CO2 leakage. Numerical assessments require capabilities to simulate complicated interactions of thermal, hydrological, geochemical multiphase processes. In this study, we utilized TOUGHREACT model to demonstrate a series of CGS simulations and assessments of (1) time evolution of aquifer responses, (2) migration distance and spatial distribution of CO2 plume, (3) effects of CO2-saline-mineral interactions, and (4) CO2 trapping components at the Changhua Costal Industrial Park (CCIP) Site, Taiwan. The CCIP Site is located at the Southern Taishi Basin with sloping and layered heterogeneous formations. At this preliminary phase, detailed information of mineralogical composition of reservoir formation and chemical composition of formation water are difficult to obtain. Mineralogical composition of sedimentary rocks and chemical compositions of formation water for CGS in deep saline aquifer from literatures (e.g. Xu et al., 2004; Marini, 2006) were adopted. CGS simulations were assumed with a constant CO2 injection rate of 1 Mt/yr at the first 50 years. Hydrogeological settings included porosities of 0.103 for shale, 0.141 for interbedding sandstone and shale, and 0.179 for sandstone; initial pore pressure distributions of 24.5 MPa to 28.7 MPa, an ambient temperature of 70°C, and 0.5 M of NaCl in aqueous solution. Mineral compositions were modified from Xu et al. (2006) to include calcite (1.9 vol. % of solid), quartz (57.9 %), kaolinite (2.0 %), illite (1.0 %), oligoclase (19.8 %), Na-smectite (3.9 %), K-feldspar (8.2 %), chlorite (4.6 %), and hematite (0.5 %) and were

Hydroquinone and Quinone-Grafted Porous Carbons for Highly Selective CO2 Capture from Flue Gases and Natural Gas Upgrading.

Science.gov (United States)

Wang, Jun; Krishna, Rajamani; Yang, Jiangfeng; Deng, Shuguang

2015-08-04

Hydroquinone and quinone functional groups were grafted onto a hierarchical porous carbon framework via the Friedel-Crafts reaction to develop more efficient adsorbents for the selective capture and removal of carbon dioxide from flue gases and natural gas. The oxygen-doped porous carbons were characterized with scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. CO2, CH4, and N2 adsorption isotherms were measured and correlated with the Langmuir model. An ideal adsorbed solution theory (IAST) selectivity for the CO2/N2 separation of 26.5 (298 K, 1 atm) was obtained on the hydroquinone-grafted carbon, which is 58.7% higher than that of the pristine porous carbon, and a CO2/CH4 selectivity value of 4.6 (298 K, 1 atm) was obtained on the quinone-grafted carbon (OAC-2), which represents a 28.4% improvement over the pristine porous carbon. The highest CO2 adsorption capacity on the oxygen-doped carbon adsorbents is 3.46 mmol g(-1) at 298 K and 1 atm. In addition, transient breakthrough simulations for CO2/CH4/N2 mixture separation were conducted to demonstrate the good separation performance of the oxygen-doped carbons in fixed bed adsorbers. Combining excellent adsorption separation properties and low heats of adsorption, the oxygen-doped carbons developed in this work appear to be very promising for flue gas treatment and natural gas upgrading.

How to characterize a potential site for CO2 storage with sparse data coverage - a Danish onshore site case

International Nuclear Information System (INIS)

Nielsen, Carsten Moller; Frykman, Peter; Dalhoff, Finn

2015-01-01

The paper demonstrates how a potential site for CO 2 storage can be evaluated up to a sufficient level of characterization for compiling a storage permit application, even if the site is only sparsely explored. The focus of the paper is on a risk driven characterization procedure. In the initial state of a site characterization process with sparse data coverage, the regional geological and stratigraphic understanding of the area of interest can help strengthen a first model construction for predictive modeling. Static and dynamic modeling in combination with a comprehensive risk assessment can guide the different elements needed to be evaluated for fulfilling a permit application. Several essential parameters must be evaluated; the storage capacity for the site must be acceptable for the project life of the operation, the trap configuration must be efficient to secure long term containment, the injectivity must be sufficient to secure a longstanding stable operation and finally a satisfactory and operational measuring strategy must be designed. The characterization procedure is demonstrated for a deep onshore aquifer in the northern part of Denmark, the Vedsted site. The site is an anticlinal structural closure in an Upper Triassic - Lower Jurassic sandstone formation at 1 800-1 900 m depth. (authors)

A joint global carbon inversion system using both CO2 and 13CO2 atmospheric concentration data

Science.gov (United States)

Chen, Jing M.; Mo, Gang; Deng, Feng

2017-03-01

Observations of 13CO2 at 73 sites compiled in the GLOBALVIEW database are used for an additional constraint in a global atmospheric inversion of the surface CO2 flux using CO2 observations at 210 sites (62 collocated with 13CO2 sites) for the 2002-2004 period for 39 land regions and 11 ocean regions. This constraint is implemented using prior CO2 fluxes estimated with a terrestrial ecosystem model and an ocean model. These models simulate 13CO2 discrimination rates of terrestrial photosynthesis and ocean-atmosphere diffusion processes. In both models, the 13CO2 disequilibrium between fluxes to and from the atmosphere is considered due to the historical change in atmospheric 13CO2 concentration. This joint inversion system using both13CO2 and CO2 observations is effectively a double deconvolution system with consideration of the spatial variations of isotopic discrimination and disequilibrium. Compared to the CO2-only inversion, this 13CO2 constraint on the inversion considerably reduces the total land carbon sink from 3.40 ± 0.84 to 2.53 ± 0.93 Pg C year-1 but increases the total oceanic carbon sink from 1.48 ± 0.40 to 2.36 ± 0.49 Pg C year-1. This constraint also changes the spatial distribution of the carbon sink. The largest sink increase occurs in the Amazon, while the largest source increases are in southern Africa, and Asia, where CO2 data are sparse. Through a case study, in which the spatial distribution of the annual 13CO2 discrimination rate over land is ignored by treating it as a constant at the global average of -14. 1 ‰, the spatial distribution of the inverted CO2 flux over land was found to be significantly modified (up to 15 % for some regions). The uncertainties in our disequilibrium flux estimation are 8.0 and 12.7 Pg C year-1 ‰ for land and ocean, respectively. These uncertainties induced the unpredictability of 0.47 and 0.54 Pg C year-1 in the inverted CO2 fluxes for land and ocean, respectively. Our joint inversion system is therefore