Science.gov

Sample records for co2 como regulador

  1. CO2-Neutral Fuels

    NASA Astrophysics Data System (ADS)

    Goede, Adelbert; van de Sanden, Richard

    2016-06-01

    Mimicking the biogeochemical cycle of System Earth, synthetic hydrocarbon fuels are produced from recycled CO2 and H2O powered by renewable energy. Recapturing CO2 after use closes the carbon cycle, rendering the fuel cycle CO2 neutral. Non-equilibrium molecular CO2 vibrations are key to high energy efficiency.

  2. CO2 laser modeling

    NASA Technical Reports Server (NTRS)

    Johnson, Barry

    1992-01-01

    The topics covered include the following: (1) CO2 laser kinetics modeling; (2) gas lifetimes in pulsed CO2 lasers; (3) frequency chirp and laser pulse spectral analysis; (4) LAWS A' Design Study; and (5) discharge circuit components for LAWS. The appendices include LAWS Memos, computer modeling of pulsed CO2 lasers for lidar applications, discharge circuit considerations for pulsed CO2 lidars, and presentation made at the Code RC Review.

  3. CO2 blood test

    MedlinePlus

    Bicarbonate test; HCO3-; Carbon dioxide test; TCO2; Total CO2; CO2 test - serum ... Many medicines can interfere with blood test results. Your health care provider will tell you if you need to stop taking any medicines before you have this test. DO ...

  4. Capnography: monitoring CO2.

    PubMed

    Casey, Georgina

    2015-10-01

    MONITORING RESPIRATORY and metabolic function by using capnography to measure end tidal carbon dioxide is standard practice in anaesthesia. It is also becoming more common in intensive care units and during procedural sedation. End tidal carbon dioxide (EtCO2) monitoring may also be used to assess effectiveness of cardiopulmonary resuscitation. Capnography is now emerging in general medical and surgical wards to monitor respiratory depression in patients using opioid analgesics. Using EtCO2 to monitor respiratory function offers many benefits over pulse oximetry. It is important to understand the differences between these two monitoring methods, and why capnography is increasingly favoured in many situations. An understanding of the physiological processes involved in CO2 excretion allows nurses to use capnography in a safe and meaningful way, while monitoring at-risk patients in acute care. PMID:26638570

  5. CO2-neutral fuels

    NASA Astrophysics Data System (ADS)

    Goede, A. P. H.

    2015-08-01

    The need for storage of renewable energy (RE) generated by photovoltaic, concentrated solar and wind arises from the fact that supply and demand are ill-matched both geographically and temporarily. This already causes problems of overcapacity and grid congestion in countries where the fraction of RE exceeds the 20% level. A system approach is needed, which focusses not only on the energy source, but includes conversion, storage, transport, distribution, use and, last but not least, the recycling of waste. Furthermore, there is a need for more flexibility in the energy system, rather than relying on electrification, integration with other energy systems, for example the gas network, would yield a system less vulnerable to failure and better adapted to requirements. For example, long-term large-scale storage of electrical energy is limited by capacity, yet needed to cover weekly to seasonal demand. This limitation can be overcome by coupling the electricity net to the gas system, considering the fact that the Dutch gas network alone has a storage capacity of 552 TWh, sufficient to cover the entire EU energy demand for over a month. This lecture explores energy storage in chemicals bonds. The focus is on chemicals other than hydrogen, taking advantage of the higher volumetric energy density of hydrocarbons, in this case methane, which has an approximate 3.5 times higher volumetric energy density. More importantly, it allows the ready use of existing gas infrastructure for energy storage, transport and distribution. Intermittent wind electricity generated is converted into synthetic methane, the Power to Gas (P2G) scheme, by splitting feedstock CO2 and H2O into synthesis gas, a mixture of CO and H2. Syngas plays a central role in the synthesis of a range of hydrocarbon products, including methane, diesel and dimethyl ether. The splitting is accomplished by innovative means; plasmolysis and high-temperature solid oxygen electrolysis. A CO2-neutral fuel cycle is

  6. CO2 laser radar

    NASA Astrophysics Data System (ADS)

    Brown, D.; Callan, R.; Constant, G.; Davies, P. H.; Foord, R.

    CO2 laser-based radars operating at 10 microns are both highly energy-efficient and eye-safe, as well as compact and rugged; they also furnish covertness-enhancing fine pointing accuracy, and are difficult to jam or otherwise confuse. Two modes of operation are generally employed: incoherent, in which the laser is simply used as a high power illumination source, and in the presently elaborated coherent or heterodyne mode. Applications encompass terrain-following and obstacle avoidance, Doppler discrimination of missile and aircraft targets, pollutant gas detection, wind measurement for weapons-aiming, and global wind field monitoring.

  7. CO2 laser preionisation

    NASA Technical Reports Server (NTRS)

    Spiers, Gary D.

    1991-01-01

    The final report for work done during the reporting period of January 25, 1990 to January 24, 1991 is presented. A literature survey was conducted to identify the required parameters for effective preionization in TEA CO2 lasers and the methods and techniques for characterizing preionizers are reviewed. A numerical model of the LP-140 cavity was used to determine the cause of the transverse mode stability improvement obtained when the cavity was lengthened. The measurement of the voltage and current discharge pulses on the LP-140 were obtained and their subsequent analysis resulted in an explanation for the low efficiency of the laser. An assortment of items relating to the development of high-voltage power supplies is also provided. A program for analyzing the frequency chirp data files obtained with the HP time and frequency analyzer is included. A program to calculate the theoretical LIMP chirp is also included and a comparison between experiment and theory is made. A program for calculating the CO2 linewidth and its dependence on gas composition and pressure is presented. The program also calculates the number of axial modes under the FWHM of the line for a given resonator length. A graphical plot of the results is plotted.

  8. CO2 Laser Market

    NASA Astrophysics Data System (ADS)

    Simonsson, Samuel

    1989-03-01

    It gives me a great deal of pleasure to introduce our final speaker of this morning's session for two reasons: First of all, his company has been very much in the news not only in our own community but in the pages of Wall Street Journal and in the world economic press. And, secondly, we would like to welcome him to our shores. He is a temporary resident of the United States, for a few months, forsaking his home in Germany to come here and help with the start up of a new company which we believe, probably, ranks #1 as the world supplier of CO2 lasers now, through the combination of former Spectra Physics Industrial Laser Division and Rofin-Sinar GMBH. Samuel Simonsson is the Chairman of the Board of Rofin-Sinar, Inc., here in the U.S. and managing director of Rofin-Sinar GMBH. It is a pleasure to welcome him.

  9. Ar + CO2 and He + CO2 Plasmas in ASTRAL

    NASA Astrophysics Data System (ADS)

    Boivin, R. F.; Gardner, A.; Munoz, J.; Kamar, O.; Loch, S.

    2007-11-01

    Spectroscopy study of the ASTRAL helicon plasma source running Ar + CO2 and He + CO2 gas mixes is presented. ASTRAL produces plasmas with the following parameters: ne = 10^10 - 10^13 cm-3, Te = 2 - 10 eV and Ti = 0.03 - 0.5 eV, B-field <= 1.3 kGauss, rf power <= 2 kWatt. A 0.33 m scanning monochromator is used for this study. Using Ar + CO2 gas mixes, very different plasmas are observed as the concentration of CO2 is changed. At low CO2 concentration, the bluish plasma is essentially atomic and argon transitions dominate the spectra. Weak C I and O I lines are present in the 750 - 1000 nm range. At higher CO2 concentration, the plasma becomes essentially molecular and is characterized by intense, white plasma columns. Here, spectra are filled with molecular bands (CO2, CO2^+, CO and CO^+). Limited molecular dissociative excitation processes associated with the production of C I and O I emission are also observed. On the other hand, He + CO2 plasmas are different. Here, rf matches are only possible at low CO2 concentration. Under these conditions, the spectra are characterized by strong C I and O I transitions with little or no molecular bands. Strong dissociative processes observed in these plasmas can be link to the high Te associated with He plasmas. An analysis of the spectra with possible scientific and industrial applications will be presented.

  10. Co2 geological sequestration

    SciTech Connect

    Xu, Tianfu

    2004-11-18

    Human activities are increasingly altering the Earth's climate. A particular concern is that atmospheric concentrations of carbon dioxide (CO{sub 2}) may be rising fast because of increased industrialization. CO{sub 2} is a so-called ''greenhouse gas'' that traps infrared radiation and may contribute to global warming. Scientists project that greenhouse gases such as CO{sub 2} will make the arctic warmer, which would melt glaciers and raise sea levels. Evidence suggests that climate change may already have begun to affect ecosystems and wildlife around the world. Some animal species are moving from one habitat to another to adapt to warmer temperatures. Future warming is likely to exceed the ability of many species to migrate or adjust. Human production of CO{sub 2} from fossil fuels (such as at coal-fired power plants) is not likely to slow down soon. It is urgent to find somewhere besides the atmosphere to put these increased levels of CO{sub 2}. Sequestration in the ocean and in soils and forests are possibilities, but another option, sequestration in geological formations, may also be an important solution. Such formations could include depleted oil and gas reservoirs, unmineable coal seams, and deep saline aquifers. In many cases, injection of CO2 into a geological formation can enhance the recovery of hydrocarbons, providing value-added byproducts that can offset the cost of CO{sub 2} capture and sequestration. Before CO{sub 2} gas can be sequestered from power plants and other point sources, it must be captured. CO{sub 2} is also routinely separated and captured as a by-product from industrial processes such as synthetic ammonia production, H{sub 2} production, and limestone calcination. Then CO{sub 2} must be compressed into liquid form and transported to the geological sequestration site. Many power plants and other large emitters of CO{sub 2} are located near geological formations that are amenable to CO{sub 2} sequestration.

  11. CO2 interaction with geomaterials.

    SciTech Connect

    Guthrie, George D.; Al-Saidi, Wissam A.; Jordan, Kenneth D.; Voora, Vamsee, K.; Romanov, Vyacheslav N.; Lopano, Christina L; Myshakin, Eugene M.; Hur, Tae Bong; Warzinski, Robert P.; Lynn, Ronald J.; Howard, Bret H.; Cygan, Randall Timothy

    2010-09-01

    This work compares the sorption and swelling processes associated with CO2-coal and CO2-clay interactions. We investigated the mechanisms of interaction related to CO2 adsortion in micropores, intercalation into sub-micropores, dissolution in solid matrix, the role of water, and the associated changes in reservoir permeability, for applications in CO2 sequestration and enhanced coal bed methane recovery. The structural changes caused by CO2 have been investigated. A high-pressure micro-dilatometer was equipped to investigate the effect of CO2 pressure on the thermoplastic properties of coal. Using an identical dilatometer, Rashid Khan (1985) performed experiments with CO2 that revealed a dramatic reduction in the softening temperature of coal when exposed to high-pressure CO2. A set of experiments was designed for -20+45-mesh samples of Argonne Premium Pocahontas No.3 coal, which is similar in proximate and ultimate analysis to the Lower Kittanning seam coal that Khan used in his experiments. No dramatic decrease in coal softening temperature has been observed in high-pressure CO2 that would corroborate the prior work of Khan. Thus, conventional polymer (or 'geopolymer') theories may not be directly applicable to CO2 interaction with coals. Clays are similar to coals in that they represent abundant geomaterials with well-developed microporous structure. We evaluated the CO2 sequestration potential of clays relative to coals and investigated the factors that affect the sorption capacity, rates, and permanence of CO2 trapping. For the geomaterials comparison studies, we used source clay samples from The Clay Minerals Society. Preliminary results showed that expandable clays have CO2 sorption capacities comparable to those of coal. We analyzed sorption isotherms, XRD, DRIFTS (infrared reflectance spectra at non-ambient conditions), and TGA-MS (thermal gravimetric analysis) data to compare the effects of various factors on CO2 trapping. In montmorillonite, CO2

  12. Leaves: Elevated CO2 levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Burning fossil fuels and land use changes such as deforestation and urbanization have led to a dramatic rise in the concentration of carbon dioxide (CO2) in the atmosphere since the onset of the Industrial Revolution. The highly dilute CO2 from the atmosphere enters plant leaves where it is concentr...

  13. CO2 Sequestration short course

    SciTech Connect

    DePaolo, Donald J.; Cole, David R; Navrotsky, Alexandra; Bourg, Ian C

    2014-12-08

    Given the public’s interest and concern over the impact of atmospheric greenhouse gases (GHGs) on global warming and related climate change patterns, the course is a timely discussion of the underlying geochemical and mineralogical processes associated with gas-water-mineral-interactions encountered during geological sequestration of CO2. The geochemical and mineralogical processes encountered in the subsurface during storage of CO2 will play an important role in facilitating the isolation of anthropogenic CO2 in the subsurface for thousands of years, thus moderating rapid increases in concentrations of atmospheric CO2 and mitigating global warming. Successful implementation of a variety of geological sequestration scenarios will be dependent on our ability to accurately predict, monitor and verify the behavior of CO2 in the subsurface. The course was proposed to and accepted by the Mineralogical Society of America (MSA) and The Geochemical Society (GS).

  14. An obsession with CO2.

    PubMed

    Jones, Norman L

    2008-08-01

    The concept that underlies this paper is that carbon dioxide (CO2) removal is at least as important as the delivery of oxygen for maximum performance during exercise. Increases in CO2 pressure and reductions in the pH of muscle influence muscle contractile properties and muscle metabolism (via effects on rate-limiting enzymes), and contribute to limiting symptoms. The approach of Barcroft exemplified the importance of integrative physiology, in describing the adaptive responses of the circulatory and respiratory systems to the demands of CO2 production during exercise. The extent to which failure in the response of one system may be countered by adaptation in another is also explained by this approach. A key factor in these linked systems is the transport of CO2 in the circulation. CO2 is mainly (90%) transported as bicarbonate ions--as such, transport of CO2 is critically related to acid-base homeostasis. Understanding in this field has been facilitated by the approach of Peter Stewart. Rooted in classical physico-chemical relationships, the approach identifies the independent variables contributing to homeostasis--the strong ion difference ([SID]), ionization of weak acids (buffers, Atot) and CO2 pressure (PCO2). The independent variables may be reliably measured or estimated in muscle, plasma, and whole blood. Equilibrium conditions are calculated to derive the dependent variables--the most important being the concentrations of bicarbonate and hydrogen ions. During heavy exercise, muscle [H+] can exceed 300 nEq.L-1 (pH 6.5), mainly due to a greatly elevated PCO2 and fall in [SID] as a result of increased lactate (La-) production. As blood flows through active muscle, [La-] increase in plasma is reduced by uptake of La- and Cl- by red blood cells, with a resultant increase in plasma [HCO3-]. Inactive muscle contributes to homeostasis through transfer of La- and Cl- into the muscle from both plasma and red blood cells; this results in a large increase in [HCO3

  15. ACCURACY OF CO2 SENSORS

    SciTech Connect

    Fisk, William J.; Faulkner, David; Sullivan, Douglas P.

    2008-10-01

    Are the carbon dioxide (CO2) sensors in your demand controlled ventilation systems sufficiently accurate? The data from these sensors are used to automatically modulate minimum rates of outdoor air ventilation. The goal is to keep ventilation rates at or above design requirements while adjusting the ventilation rate with changes in occupancy in order to save energy. Studies of energy savings from demand controlled ventilation and of the relationship of indoor CO2 concentrations with health and work performance provide a strong rationale for use of indoor CO2 data to control minimum ventilation rates1-7. However, this strategy will only be effective if, in practice, the CO2 sensors have a reasonable accuracy. The objective of this study was; therefore, to determine if CO2 sensor performance, in practice, is generally acceptable or problematic. This article provides a summary of study methods and findings ? additional details are available in a paper in the proceedings of the ASHRAE IAQ?2007 Conference8.

  16. CO2 Sequestration Crosswell Monitoring

    NASA Astrophysics Data System (ADS)

    Morency, C.; Luo, Y.; Tromp, J.

    2010-12-01

    Geologic sequestration of CO2, a green house gas, represents an effort to reduce the large amount of CO2 generated as a by-product of fossil fuels combustion and emitted into the atmosphere. This process of sequestration involves CO2 storage deep underground into highly permeable porous media sealed by caprock. "4D seismics" is a natural non-intrusive monitoring technique which involves 3D time-lapse seismic surveys. The success of monitoring CO2 movement relies upon a proper description of the physics of the problem. We realize time-lapse migrations comparing acoustic, elastic (with or without Gassmann's formulae), and poroelastic simulations of 4D seismic imaging. This approach highlights the influence of using different physical theories on interpreting seismic data, and, more importantly, on extracting the CO2 signature from the seismic wave field. We investigate various types of inversions using (1) P-wave traveltimes, (2) P- & S-wave traveltimes and (3) P- & S-wave traveltimes and amplitudes. Simulations are performed using a spectral-element method, and finite-frequency sensitivity kernels, used in the non-linear iterative inversions, are calculated based on an adjoint method. Biot's equations are implemented in the forward and adjoint simulations to account for poroelastic effects.

  17. Update on CO2 emissions

    SciTech Connect

    Friedingstein, P.; Houghton, R.A.; Marland, Gregg; Hackler, J.; Boden, Thomas A; Conway, T.J.; Canadell, J.G.; Raupach, Mike; Ciais, Philippe; Le Quere, Corrine

    2010-12-01

    Emissions of CO2 are the main contributor to anthropogenic climate change. Here we present updated information on their present and near-future estimates. We calculate that global CO2 emissions from fossil fuel burning decreased by 1.3% in 2009 owing to the global financial and economic crisis that started in 2008; this is half the decrease anticipated a year ago1. If economic growth proceeds as expected2, emissions are projected to increase by more than 3% in 2010, approaching the high emissions growth rates that were observed from 2000 to 20081, 3, 4. We estimate that recent CO2 emissions from deforestation and other land-use changes (LUCs) have declined compared with the 1990s, primarily because of reduced rates of deforestation in the tropics5 and a smaller contribution owing to forest regrowth elsewhere.

  18. The CO2nnect activities

    NASA Astrophysics Data System (ADS)

    Eugenia, Marcu

    2014-05-01

    Climate change is one of the biggest challenges we face today. A first step is the understanding the problem, more exactly what is the challenge and the differences people can make. Pupils need a wide competencies to meet the challenges of sustainable development - including climate change. The CO2nnect activities are designed to support learning which can provide pupils the abilities, skills, attitudes and awareness as well as knowledge and understanding of the issues. The project "Together for a clean and healthy world" is part of "The Global Educational Campaign CO2nnect- CO2 on the way to school" and it was held in our school in the period between February and October 2009. It contained a variety of curricular and extra-curricular activities, adapted to students aged from 11 to 15. These activities aimed to develop in students the necessary skills to understanding man's active role in improving the quality of the environment, putting an end to its degrading process and to reducing the effects of climate changes caused by the human intervention in nature, including transport- a source of CO2 pollution. The activity which I propose can be easily adapted to a wide range of age groups and linked to the curricula of many subjects: - Investigate CO2 emissions from travel to school -Share the findings using an international database -Compare and discuss CO2 emissions -Submit questions to a climate- and transport expert -Partner with other schools -Meet with people in your community to discuss emissions from transport Intended learning outcomes for pupils who participate in the CO2nnect campaign are: Understanding of the interconnected mobility- and climate change issue climate change, its causes and consequences greenhouse-gas emissions from transport and mobility the interlinking of social, environmental, cultural and economic aspects of the local transport system how individual choices and participation can contribute to creating a more sustainable development

  19. Reducing cement's CO2 footprint

    USGS Publications Warehouse

    van Oss, Hendrik G.

    2011-01-01

    The manufacturing process for Portland cement causes high levels of greenhouse gas emissions. However, environmental impacts can be reduced by using more energy-efficient kilns and replacing fossil energy with alternative fuels. Although carbon capture and new cements with less CO2 emission are still in the experimental phase, all these innovations can help develop a cleaner cement industry.

  20. CO2 Acquisition Membrane (CAM)

    NASA Technical Reports Server (NTRS)

    Mason, Larry W.; Way, J. Douglas; Vlasse, Marcus

    2003-01-01

    The objective of CAM is to develop, test, and analyze thin film membrane materials for separation and purification of carbon dioxide (CO2) from mixtures of gases, such as those found in the Martian atmosphere. The membranes are targeted toward In Situ Resource Utilization (ISRU) applications that will operate in extraterrestrial environments and support future unmanned and human space missions. A primary application is the Sabatier Electrolysis process that uses Mars atmosphere CO2 as raw material for producing water, oxygen, and methane for rocket fuel and habitat support. Other applications include use as an inlet filter to collect and concentrate Mars atmospheric argon and nitrogen gases for habitat pressurization, and to remove CO2 from breathing gases in Closed Environment Life Support Systems (CELSS). CAM membrane materials include crystalline faujasite (FAU) zeolite and rubbery polymers such as silicone rubber (PDMS) that have been shown in the literature and via molecular simulation to favor adsorption and permeation of CO2 over nitrogen and argon. Pure gas permeation tests using commercial PDMS membranes have shown that both CO2 permeance and the separation factor relative to other gases increase as the temperature decreases, and low (Delta)P(Sub CO2) favors higher separation factors. The ideal CO2/N2 separation factor increases from 7.5 to 17.5 as temperature decreases from 22 C to -30 C. For gas mixtures containing CO2, N2, and Ar, plasticization decreased the separation factors from 4.5 to 6 over the same temperature range. We currently synthesize and test our own Na(+) FAU zeolite membranes using standard formulations and secondary growth methods on porous alumina. Preliminary tests with a Na(+) FAU membrane at 22 C show a He/SF6 ideal separation factor of 62, exceeding the Knudsen diffusion selectivity by an order of magnitude. This shows that the membrane is relatively free from large defects and associated non-selective (viscous flow) transport

  1. Estimation of continuous anthropogenic CO2 using CO2, CO, δ13C(CO2) and Δ14C(CO2)

    NASA Astrophysics Data System (ADS)

    Vardag, S. N.; Gerbig, C.; Janssens-Maenhout, G.; Levin, I.

    2015-07-01

    We investigate different methods for estimating anthropogenic CO2 using modelled continuous atmospheric concentrations of CO2 alone, as well as CO2 in combination with the surrogate tracers CO, δ13C(CO2) and Δ14C(CO2). These methods are applied at three hypothetical stations representing rural, urban and polluted conditions. We find that independent of the tracer used, an observation-based estimate of continuous anthropogenic CO2 is not feasible at rural measurement sites due to the low signal to noise ratio of anthropogenic CO2 estimates at such settings. At urban and polluted sites, potential future continuous Δ14C(CO2) measurements with a precision of 5 ‰ or better are most promising for anthropogenic CO2 determination (precision ca. 10-20%), but the insensitivity against CO2 contributions from biofuel emissions may reduce its accuracy in the future. Other tracers, such as δ13C(CO2) and CO could provide an accurate and already available alternative if all CO2 sources in the catchment area are well characterized with respect to their isotopic signature and CO to anthropogenic CO2 ratio. We suggest a strategy for calibrating these source characteristics on an annual basis using precise Δ14C(CO2) measurements on grab samples. The precision of anthropogenic CO2 determination using δ13C(CO2) is largely determined by the measurement precision of δ13C(CO2) and CO2. The precision when using the CO-method is mainly limited by the variation of natural CO sources and CO sinks. At present, continuous anthropogenic CO2 could be determined using the tracers δ13C(CO2) and/or CO with a precision of about 30 %, a mean bias of about 10 % and without significant diurnal discrepancies. This allows significant improvement, validation and bias reduction of highly resolved emission inventories using atmospheric observation and regional modelling.

  2. Surface Condensation of CO2 onto Kaolinite

    SciTech Connect

    Schaef, Herbert T.; Glezakou, Vassiliki Alexandra; Owen, Antionette T.; Ramprasad, Sudhir; Martin, Paul F.; McGrail, B. Peter

    2014-02-11

    The fundamental adsorption behavior of gaseous and supercritical carbon dioxide (CO2) onto poorly crystalline kaolinite (KGa-2) at conditions relevant to geologic sequestration has been investigated using a quartz crystal microbalance (QCM) and density functional theory (DFT) methods. The QCM data indicated linear adsorption of CO2 (0-0.3 mmol CO2/g KGa-2) onto the kaolinite surface up through the gaseous state (0.186 g/cm3). However in the supercritical region, CO2 adsorption increases dramatically, reaching a peak (0.9-1.0 mmol CO2/g KGa-2) near 0.43 g/cm3, before declining rapidly to surface adsorption values equivalent or below gaseous CO2. This adsorption profile was not observed with He or N2. Comparative density functional studies of CO2 interactions with kaolinite surface models rule out CO2 intercalation and confirm that surface adsorption is favored up to approximately 0.35 g/cm3 of CO2, showing distorted T-shaped CO2-CO2 clustering, typical of supercritical CO2 aggregation over the surface as the density increases. Beyond this point, the adsorption energy gain for any additional CO2 becomes less than the CO2 interaction energy (~0.2 eV) in the supercritical medium resulting in overall desorption of CO2 from the kaolinite surface.

  3. Outsourcing CO2 within China

    PubMed Central

    Feng, Kuishuang; Davis, Steven J.; Sun, Laixiang; Li, Xin; Guan, Dabo; Liu, Weidong; Liu, Zhu; Hubacek, Klaus

    2013-01-01

    Recent studies have shown that the high standard of living enjoyed by people in the richest countries often comes at the expense of CO2 emissions produced with technologies of low efficiency in less affluent, developing countries. Less apparent is that this relationship between developed and developing can exist within a single country’s borders, with rich regions consuming and exporting high-value goods and services that depend upon production of low-cost and emission-intensive goods and services from poorer regions in the same country. As the world’s largest emitter of CO2, China is a prominent and important example, struggling to balance rapid economic growth and environmental sustainability across provinces that are in very different stages of development. In this study, we track CO2 emissions embodied in products traded among Chinese provinces and internationally. We find that 57% of China’s emissions are related to goods that are consumed outside of the province where they are produced. For instance, up to 80% of the emissions related to goods consumed in the highly developed coastal provinces are imported from less developed provinces in central and western China where many low–value-added but high–carbon-intensive goods are produced. Without policy attention to this sort of interprovincial carbon leakage, the less developed provinces will struggle to meet their emissions intensity targets, whereas the more developed provinces might achieve their own targets by further outsourcing. Consumption-based accounting of emissions can thus inform effective and equitable climate policy within China. PMID:23754377

  4. Intelligent CO 2 beam guiding

    NASA Astrophysics Data System (ADS)

    Brecher, Christian; Stimpfl, Joffrey; Emonts, Michael

    The Fraunhofer IPT has recently developed a self-diagnosing laser system technology which can monitor the process parameters of all laser system components and supports the adjustment of the beam guidance of CO2 laser production systems with large ranges of travel. The intelligent system furthermore interprets the correlated laser beam parameter responses and proposes appropriate measures for preventive maintenance. The new assisted beam guidance adjustment bases upon active reflector modules adjusting with a large angular range of average ±0.8∘ at maximum resolution and a position-sensitive detector for the position of the pilot laser.

  5. Passive CO2 concentration in higher plants.

    PubMed

    Sage, Rowan F; Khoshravesh, Roxana

    2016-06-01

    Photorespiratory limitations on C3 photosynthesis are substantial in warm, low CO2 conditions. To compensate, certain plants evolved mechanisms to actively concentrate CO2 around Rubisco using ATP-supported CO2 pumps such as C4 photosynthesis. Plants can also passively accumulate CO2 without additional ATP expenditure by localizing the release of photorespired and respired CO2 around Rubisco that is diffusively isolated from peripheral air spaces. Passive accumulation of photorespired CO2 occurs when glycine decarboxylase is localized to vascular sheath cells in what is termed C2 photosynthesis, and through forming sheaths of chloroplasts around the periphery of mesophyll cells. The peripheral sheaths require photorespired CO2 to re-enter chloroplasts where it can be refixed. Passive accumulation of respiratory CO2 is common in organs such as stems, fruits and flowers, due to abundant heterotrophic tissues and high diffusive resistance along the organ periphery. Chloroplasts within these organs are able to exploit this high CO2 to reduce photorespiration. CO2 concentration can also be enhanced passively by channeling respired CO2 from roots and rhizomes into photosynthetic cells of stems and leaves via lacunae, aerenchyma and the xylem stream. Through passive CO2 concentration, C3 species likely improved their carbon economy and maintained fitness during episodes of low atmospheric CO2. PMID:27058940

  6. Optical properties of heusler alloys Co2FeSi, Co2FeAl, Co2CrAl, and Co2CrGa

    NASA Astrophysics Data System (ADS)

    Shreder, E. I.; Svyazhin, A. D.; Belozerova, K. A.

    2013-11-01

    The results of an investigation of optical properties and the calculations of the electronic structure of Co2FeSi, Co2FeAl, Co2CrAl, and Co2CrGa Heusler alloys are presented. The main focus of our attention is the study of the spectral dependence of the real part (ɛ1) and imaginary part (ɛ2) of the dielectric constant in the range of wavelengths λ = 0.3-13 μm using the ellipsometric method. An anomalous behavior of the optical conductivity σ(ω) has been found in the infrared range in the Co2CrAl and Co2CrGa alloys, which differs substantially from that in the Co2FeSi and Co2FeAl alloys. The results obtained are discussed based on the calculations of the electronic structure.

  7. CO2 laser frequency multiplication

    SciTech Connect

    Not Available

    1992-03-01

    The duration of the mode-locked CO(2) laser pulses was measured to be 0.9 + or - nsec by the technique of (second harmonic) autocorrelation. Knowing the pulse duration, the spot size, and the harmonic conversion efficiency, a detailed fit of experiment to theory gave an estimate of the nonlinear coefficient of AgGaSe(2). d36 = 31 + or - V(1), in agreement with the most accurate literature values. A number of experiments were made with longer pulse trains in which the highest harmonic energy conversion reached 78%. The damage threshold was measured and it turned out to be related much more strongly to fluence than intensity. The shorter pulse trains had peak intensities of close to 300 MW 1/cm squared whereas the longer trains (3 usec) had intensities up to 40 MW 1/cm squared.

  8. Sequestration of CO2 by halotolerant algae

    PubMed Central

    2014-01-01

    The potential of halotolerant algae isolated from natural resources was used to study CO2 fixation and algal lipid production. Biological fixation of CO2 in photobioreactor in presence of salinity is exploited. The CO2 concentration 1060 ppm gave the highest biomass yield (700 mg dry wt/l), the highest total lipid content (10.33%) with 80% of CO2 removal. PMID:24847439

  9. CO2 mitigation via accelerated limestone weathering

    USGS Publications Warehouse

    Rau, G.H.; Knauss, K.G.; Langer, W.H.; Caldeira, K.

    2004-01-01

    The climate and environmental impacts of the current, carbon-intensive energy usage demands that effective and practical energy alternatives and CO2 mitigation strategies be found. A discussion on CO2 mitigation via accelerated limestone weathering covers limestone and seawater availability and cost; reaction rates and densities; effectiveness in CO2 sequestration; and environmental impacts and benefits.

  10. Recent Trends in Atmospheric 14CO2

    NASA Astrophysics Data System (ADS)

    Turnbull, J. C.; Rayner, P.; Bousquet, P.; Cozic, A.; Miller, J. B.; Lehman, S. J.; Peters, W.; Tans, P. P.; Ciais, P.

    2007-12-01

    The radiocarbon content of atmospheric CO2 (14CO2) varies due to a number of factors. After the near-doubling of the 14CO2 loading in the early 1960s (due to atmospheric nuclear weapons testing), many studies examined the fate of this 'bomb 14C' to understand exchange processes of CO2 with the surface reservoirs. Today, however, the atmosphere and surface reservoirs are close to equilibrium with respect to bomb 14C, and instead, changes in 14CO2 more strongly reflect the response to the addition of 14C-free fossil fuel CO2 to the atmosphere. We use an atmospheric transport model to simulate recent atmospheric 14CO2, and compare this to observations at several sites over the Northern Hemisphere continents. We show that, in the Northern Hemisphere, 14CO2 variability is dominated by the effect of fossil fuel CO2 emissions. The model simulates the time trends quite well, including both the overall secular trend and the seasonal cycle. A seasonal cycle in 14CO2 is observed at the high altitude sites of Niwot Ridge, Colorado, and Jungfraujoch, Switzerland, but the magnitude varies from year to year. Our modeling studies demonstrate that this inter-annual variability can be explained by differences in atmospheric transport. This is in contrast to CO2 concentration seasonal cycles, which are dominated by seasonal changes in CO2 source strengths.

  11. Photosynthesis in a CO2 rich atmosphere

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The concentration of CO2 ([CO2]) in the atmosphere is projected to reach ~550 ppm by 2050. C3 plants respond directly to growth at elevated [CO2] via stimulated photosynthesis and reduced stomatal conductance. The enhancement of photosynthesis is the result of increased velocity of carboxylation of ...

  12. Isotopic CO2 Instrumentation for UAV Measurements

    NASA Astrophysics Data System (ADS)

    Gomez, A.; Silver, J.

    2013-12-01

    Carbon dioxide is the largest component of anthroprogenic green house gas emissions. Knowing atmospheric 13CO2/12CO2 ratios precisely is important for understanding biogenic and anthroprogenic sources and sinks for carbon. Instrumentation mounted on UAV aircraft would enable important spatial isotopic CO2 information. However, current isotopic CO2 instrumentation have unfavorable attributes for UAV use, such as high power requirements, high cost, high weight, and large size. Here we present the early development of a compact isotopic CO2 instrument that is designed to nullify effects of pressure, temperature and moisture, and will ultimately be suitable for UAV deployment.

  13. Forest succession at elevated CO2

    SciTech Connect

    Clark, James S.; Schlesinger, William H.

    2002-02-01

    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.

  14. Selecting CO2 Sources for CO2 Utilization by Environmental-Merit-Order Curves.

    PubMed

    von der Assen, Niklas; Müller, Leonard J; Steingrube, Annette; Voll, Philip; Bardow, André

    2016-02-01

    Capture and utilization of CO2 as alternative carbon feedstock for fuels, chemicals, and materials aims at reducing greenhouse gas emissions and fossil resource use. For capture of CO2, a large variety of CO2 sources exists. Since they emit much more CO2 than the expected demand for CO2 utilization, the environmentally most favorable CO2 sources should be selected. For this purpose, we introduce the environmental-merit-order (EMO) curve to rank CO2 sources according to their environmental impacts over the available CO2 supply. To determine the environmental impacts of CO2 capture, compression and transport, we conducted a comprehensive literature study for the energy demands of CO2 supply, and constructed a database for CO2 sources in Europe. Mapping these CO2 sources reveals that CO2 transport distances are usually small. Thus, neglecting transport in a first step, we find that environmental impacts are minimized by capturing CO2 first from chemical plants and natural gas processing, then from paper mills, power plants, and iron and steel plants. In a second step, we computed regional EMO curves considering transport and country-specific impacts for energy supply. Building upon regional EMO curves, we identify favorable locations for CO2 utilization with lowest environmental impacts of CO2 supply, so-called CO2 oases. PMID:26752014

  15. Microbial Growth under Supercritical CO2

    PubMed Central

    Peet, Kyle C.; Freedman, Adam J. E.; Hernandez, Hector H.; Britto, Vanya; Boreham, Chris; Ajo-Franklin, Jonathan B.

    2015-01-01

    Growth of microorganisms in environments containing CO2 above its critical point is unexpected due to a combination of deleterious effects, including cytoplasmic acidification and membrane destabilization. Thus, supercritical CO2 (scCO2) is generally regarded as a sterilizing agent. We report isolation of bacteria from three sites targeted for geologic carbon dioxide sequestration (GCS) that are capable of growth in pressurized bioreactors containing scCO2. Analysis of 16S rRNA genes from scCO2 enrichment cultures revealed microbial assemblages of varied complexity, including representatives of the genus Bacillus. Propagation of enrichment cultures under scCO2 headspace led to isolation of six strains corresponding to Bacillus cereus, Bacillus subterraneus, Bacillus amyloliquefaciens, Bacillus safensis, and Bacillus megaterium. Isolates are spore-forming, facultative anaerobes and capable of germination and growth under an scCO2 headspace. In addition to these isolates, several Bacillus type strains grew under scCO2, suggesting that this may be a shared feature of spore-forming Bacillus spp. Our results provide direct evidence of microbial activity at the interface between scCO2 and an aqueous phase. Since microbial activity can influence the key mechanisms for permanent storage of sequestered CO2 (i.e., structural, residual, solubility, and mineral trapping), our work suggests that during GCS microorganisms may grow and catalyze biological reactions that influence the fate and transport of CO2 in the deep subsurface. PMID:25681188

  16. Residual CO2 trapping in Indiana limestone.

    PubMed

    El-Maghraby, Rehab M; Blunt, Martin J

    2013-01-01

    We performed core flooding experiments on Indiana limestone using the porous plate method to measure the amount of trapped CO(2) at a temperature of 50 °C and two pressures: 4.2 and 9 MPa. Brine was mixed with CO(2) for equilibration, then the mixture was circulated through a sacrificial core. Porosity and permeability tests conducted before and after 884 h of continuous core flooding confirmed negligible dissolution. A trapping curve for supercritical (sc)CO(2) in Indiana showing the relationship between the initial and residual CO(2) saturations was measured and compared with that of gaseous CO(2). The results were also compared with scCO(2) trapping in Berea sandstone at the same conditions. A scCO(2) residual trapping end point of 23.7% was observed, indicating slightly less trapping of scCO(2) in Indiana carbonates than in Berea sandstone. There is less trapping for gaseous CO(2) (end point of 18.8%). The system appears to be more water-wet under scCO(2) conditions, which is different from the trend observed in Berea; we hypothesize that this is due to the greater concentration of Ca(2+) in brine at higher pressure. Our work indicates that capillary trapping could contribute to the immobilization of CO(2) in carbonate aquifers. PMID:23167314

  17. Fourier Transform Microwave Spectra of CO{2}-ETHYLENE Sulfide, CO{2}-ETHYLENE Oxide and CO{2}-PROPYLENE Oxide Complexes

    NASA Astrophysics Data System (ADS)

    Orita, Yukari; Kawashima, Yoshiyuki; Hirota, Eizi

    2010-06-01

    We have previously examined the difference in roles of O and S in structure and dynamics of the CO-ethylene oxide (EO) and CO-ethylene sulfide (ES) complexes. We have extended the investigation to CO{2}-EO and CO{2}-ES for comparison. We have also observed the CO{2}-propylene oxide (PO) complex, which is an important intermediate in the reaction of PO with CO{2} leading to polycarbonate. Both a-type and b-type transitions were observed for the CO{2}-EO and CO{2}-ES, but no c-type transitions were observed at all. We also detected the {34}S and {13}C isotopic species in natural abundance and the species containing {18}OCO and C{18}O% {2}, which were synthesized by burning paper in an {18}O{2} and{% 16}O{2} mixture. By analyzing the observed spectra we concluded the CO{2} moiety of CO{2}-EO and CO{2}-ES located in a plane % prependicular to the three-membered ring and bisecting the COC or CSC angle of EO or ES, respectively, as in the case of CO-EO and CO-ES complexes. An % ab initio MO calculation at the level of MP2/6-311G(d, p) yielded an optimized structure in good agreement with the experimental result. We have derived from the observed spectra the distance, the stretching force constant, and the binding energy of the bonds between the constituents of the CO{2}-EO and CO{2}-ES complexes and have found that the distances of the two complexes were shorter by 0.2Å than those in CO-EO and CO-ES, respectively, and that the intermolecular bonds were two times stronger in the CO{2} complexes than in the corresponding CO complexes. We have concluded from the observed spectra that the CO{2} moiety in CO{2}-PO is located on the PO three-membered ring plane opposite to the methyl group. The constituents in CO{2}-PO were more weakly bound than those in CO{2}-EO and CO{2}-ES. S. Sato, Y. Kawashima, Y. Tatamitani, and E. Hirota, 63rd International Symposium on Molecular Spectroscopy, WF05 (2008).

  18. Energyless CO2 Absorption, Generation, and Fixation Using Atmospheric CO2.

    PubMed

    Inagaki, Fuyuhiko; Okada, Yasuhiko; Matsumoto, Chiaki; Yamada, Masayuki; Nakazawa, Kenta; Mukai, Chisato

    2016-01-01

    From an economic and ecological perspective, the efficient utilization of atmospheric CO2 as a carbon resource should be a much more important goal than reducing CO2 emissions. However, no strategy to harvest CO2 using atmospheric CO2 at room temperature currently exists, which is presumably due to the extremely low concentration of CO2 in ambient air (approximately 400 ppm=0.04 vol%). We discovered that monoethanolamine (MEA) and its derivatives efficiently absorbed atmospheric CO2 without requiring an energy source. We also found that the absorbed CO2 could be easily liberated with acid. Furthermore, a novel CO2 generator enabled us to synthesize a high value-added material (i.e., 2-oxazolidinone derivatives based on the metal catalyzed CO2-fixation at room temperature) from atmospheric CO2. PMID:26596773

  19. Exogenously produced CO2 doubles the CO2 efflux from three north temperate lakes

    NASA Astrophysics Data System (ADS)

    Wilkinson, Grace M.; Buelo, Cal D.; Cole, Jonathan J.; Pace, Michael L.

    2016-03-01

    It is well established that lakes are typically sources of CO2 to the atmosphere. However, it remains unclear what portion of CO2 efflux is from endogenously processed organic carbon or from exogenously produced CO2 transported into lakes. We estimated high-frequency CO2 and O2 efflux from three north temperate lakes in summer to determine the proportion of the total CO2 efflux that was exogenously produced. Two of the lakes were amended with nutrients to experimentally enhance endogenous CO2 uptake. In the unfertilized lake, 50% of CO2 efflux was from exogenous sources and hydrology had a large influence on efflux. In the fertilized lakes, endogenous CO2 efflux was negative (into the lake) yet exogenous CO2 made the lakes net sources of CO2 to the atmosphere. Shifts in hydrologic regimes and nutrient loading have the potential to change whether small lakes act primarily as reactors or vents in the watershed.

  20. CO2 transport over complex terrain

    USGS Publications Warehouse

    Sun, Jielun; Burns, Sean P.; Delany, A.C.; Oncley, S.P.; Turnipseed, A.A.; Stephens, B.B.; Lenschow, D.H.; LeMone, M.A.; Monson, Russell K.; Anderson, D.E.

    2007-01-01

    CO2 transport processes relevant for estimating net ecosystem exchange (NEE) at the Niwot Ridge AmeriFlux site in the front range of the Rocky Mountains, Colorado, USA, were investigated during a pilot experiment. We found that cold, moist, and CO2-rich air was transported downslope at night and upslope in the early morning at this forest site situated on a ???5% east-facing slope. We found that CO2 advection dominated the total CO2 transport in the NEE estimate at night although there are large uncertainties because of partial cancellation of horizontal and vertical advection. The horizontal CO2 advection captured not only the CO2 loss at night, but also the CO2 uptake during daytime. We found that horizontal CO2 advection was significant even during daytime especially when turbulent mixing was not significant, such as in early morning and evening transition periods and within the canopy. Similar processes can occur anywhere regardless of whether flow is generated by orography, synoptic pressure gradients, or surface heterogeneity as long as CO2 concentration is not well mixed by turbulence. The long-term net effect of all the CO2 budget terms on estimates of NEE needs to be investigated. ?? 2007 Elsevier B.V. All rights reserved.

  1. Covalent Organic Frameworks for CO2 Capture.

    PubMed

    Zeng, Yongfei; Zou, Ruqiang; Zhao, Yanli

    2016-04-01

    As an emerging class of porous crystalline materials, covalent organic frameworks (COFs) are excellent candidates for various applications. In particular, they can serve as ideal platforms for capturing CO2 to mitigate the dilemma caused by the greenhouse effect. Recent research achievements using COFs for CO2 capture are highlighted. A background overview is provided, consisting of a brief statement on the current CO2 issue, a summary of representative materials utilized for CO2 capture, and an introduction to COFs. Research progresses on: i) experimental CO2 capture using different COFs synthesized based on different covalent bond formations, and ii) computational simulation results of such porous materials on CO2 capture are summarized. Based on these experimental and theoretical studies, careful analyses and discussions in terms of the COF stability, low- and high-pressure CO2 uptake, CO2 selectivity, breakthrough performance, and CO2 capture conditions are provided. Finally, a perspective and conclusion section of COFs for CO2 capture is presented. Recent advancements in the field are highlighted and the strategies and principals involved are discussed. PMID:26924720

  2. Radiocarbon in Tree STEM CO2 Efflux

    NASA Astrophysics Data System (ADS)

    Muhr, J.; Czimczik, C. I.; Angert, A.; Trumbore, S.

    2011-12-01

    Carbon dioxide efflux from tree stems can be a significant component of the stand-level carbon balance. Recent studies have demonstrated that tree stem CO2 efflux may reflect more than just in-situ respiration but also transport from other locations and it has been suggested that it may also include C originally respired in roots or even uptake of soil CO2. We report measurements of the radiocarbon signature of carbon emitted from a range of mature tree stems in tropical and temperate forest ecosystems. Comparison of the radiocarbon signature of respired CO2 with the observed rate of decline in atmsopheric 14C-CO2 provides a measure of the time elapsed between C fixation by the plant and its return to the atmosphere as stem CO2 efflux. In all investigated trees, we observed that stem CO2 efflux had higher radiocarbon signatures than the contemporary atmospheric 14C-CO2, and therefore was derived from C fixed one to several years earlier. In tropical forest trees, we found that the 14C signature of CO2 within the stem (~4-5 cm depth) had even higher radiocarbon signatures than the stem CO2 efflux. In one of the investigated tree species, the in-stem CO2 was derived from C sources fixed on average ~20 years previously. These results confirm observations of root-respired CO2 that also have shown contributions of C substrates older than recent photosynthetic products, and the presence of extracable C reserves in wood that reflect the presence of older C sources. Our results imply that stem CO2 efflux is not only derived from respiration of recent photosynthetic products but includes contributions from older, stored C pools. Ongoing investigations will enable us to compare CO2 efflux for trees subjected to experimental drought, and using different life strategies (deciduous versus evergreen oaks) to determine if the use of these older C stores varies with stress.

  3. Global CO2 Emission from Volcanic Lakes

    NASA Astrophysics Data System (ADS)

    Perez, N.; Hernandez Perez, P. A.; Padilla, G.; Melian Rodriguez, G.; Padron, E.; Barrancos, J.; Calvo, D.; Kusukabe, M.; Mori, T.; Nolasco, D.

    2009-12-01

    During the last two decades, scientists have paid attention to CO2 volcanic emissions and its contribution to the global C budget. Excluding MORBs as a net source of CO2 to the atmosphere, the global CO2 discharge from subaerial volcanism has been estimated about 300 Mt y-1 and this rate accounts for both visible (plume & fumaroles) and non-visible (diffuse) volcanic gas emanations (Mörner & Etíope, 2002). However, CO2 emissions from volcanic lakes have not been considered to estimate the global CO2 discharge from subaerial volcanoes. In order to improve this global CO2 emission rate and estimate the global CO2 emission from volcanic lakes, an extensive research on CO2 emission of volcanic lakes from Phillipines, Nicaragua, Guatemala, Mexico, Indonesia, Germany, France, Cameroon, Costa Rica, El Salvador and Ecuador had been recently carried out. In-situ measurements of CO2 efflux from the surface environment of volcanic lakes were performed by means of a modified floating device of the accumulation chamber method. To quantify the total CO2 emission from each volcanic lake, CO2 efflux maps were constructed using sequential Gaussian simulations (sGs). CO2 emission rates were normalized by the lake area (km2), and volcanic lakes were grouped following classification in acid, alkaline and neutral lakes. The observed average normalized CO2 emission rate values increase from alkaline (5.5 t km-2 d-1), neutral (210.0 t km-2 d-1), to acid (676.8 t km-2 d-1) volcanic lakes. Taking into account (i) these normalized CO2 emission rates from 31 volcanic lakes, (ii) the number of volcanic lakes in the world (~ 1100), (iii) the fraction of the investigated alkaline (45%), neutral (39%), and acid (16%) volcanic lakes, and (iv) the average areas of the investigated alkaline (36,8 km2), neutral (3,7 km2), and acid (0,5 km2) volcanic lakes; the global CO2 emission from volcanic lakes is about ~ 182 Mt year-1. This estimated value is about ~ 50% of the actual estimated global CO2

  4. Soft Approaches to CO2 Activation.

    PubMed

    Das, Shoubhik; Bobbink, Felix D; Gopakumar, Aswin; Dyson, Paul J

    2015-01-01

    The utilization of CO(2) as a C1 synthon is becoming increasingly important as a feedstock derived from carbon capture and storage technologies. Herein, we describe some of our recent research on carbon dioxide valorization, notably, using organocatalysts to convert CO(2) into carboxylic acid, ester, formyl and methyl groups on various organic molecules. We describe these studies within the broader context of CO(2) capture and valorization and suggest approaches for future research. PMID:26842327

  5. CO2 sequestration: Storage capacity guideline needed

    USGS Publications Warehouse

    Frailey, S.M.; Finley, R.J.; Hickman, T.S.

    2006-01-01

    Petroleum reserves are classified for the assessment of available supplies by governmental agencies, management of business processes for achieving exploration and production efficiency, and documentation of the value of reserves and resources in financial statements. Up to the present however, the storage capacity determinations made by some organizations in the initial CO2 resource assessment are incorrect technically. New publications should thus cover differences in mineral adsorption of CO2 and dissolution of CO2 in various brine waters.

  6. Global Mapping of CO2 on Enceladus

    NASA Astrophysics Data System (ADS)

    McCord, T. B.; Combe, J. P.; Matson, D.; Johnson, T. V.

    2014-12-01

    We present the first global map of CO2 on Enceladus. The purpose is to determine whether CO2 is associated to fractures and eruptions, and if it formed recently. Cassini observed tectonic features and plumes on Enceladus, which could be caused by a warm subsurface ocean containing dissolved gases. CO2 should be one of these gases (Postberg F. et al., Nature, 2009), and some of it should be erupted and condensed onto the surface (Matson et al., Icarus, 2012). Validation of this hypothesis could be done by determining the amount, location and molecular state of the CO2. Free CO2 ice and complexed CO2 were reported on Enceladus (Brown et al., Science, 2006; Hansen, LPSC, 2010) from analysis of Cassini Visual and Infrared Mapping Spectrometer (VIMS) data, and on other Saturn icy satellites (Cruikshank et al., Icarus, 2010 ; Filacchione et al., Icarus, 2010). Complexed CO2 has also been found from Galileo Near-Infrared Mapping Spectrometer (NIMS) spectra on the icy Galilean satellites (McCord et al., Science, 1997 and JGR, 1998), apparently due to both interior outgassing and radiation processing. CO2 has an asymmetric stretching mode that creates an absorption band, the wavelength position of which is sensitive to the nature of molecular associations between CO2 and their neighbors. Free CO2 ice absorbs at 4.268 μm for (Sandford and Allamandola, 1990) and CO2 complexed with other molecules absorbs at shorter wavelengths, around 4.25 μm or shorter (Chaban et al., Icarus, 2007). In VIMS spectra of Enceladus, this stretching mode absorption band is near the instrument detection limit. We utilized all VIMS data sets available that had significant spatial resolution to increase the statistics of the observations for any given location and improve the signal to noise. CO2 has also a smaller absorption at 2.7 μm, although it occurs in a range of wavelength that has higher signal-to-noise ratio by several magnitudes, because the surface of Enceladus (mostly H2O ice) has

  7. CO2 MITIGATION VIA ACCELERATED LIMESTONE WEATHERING

    SciTech Connect

    Rau, G H; Knauss, K G; Langer, W H; Caldeira, K G

    2004-02-27

    The climate and environmental impacts of our current, carbon-intensive energy usage demands that effective and practical energy alternatives and CO2 mitigation strategies be found. As part of this effort, various means of capturing and storing CO2 generated from fossil-fuel-based energy production are being investigated. One of the proposed methods involves a geochemistry-based capture and sequestration process that hydrates point-source, waste CO2 with water to produce a carbonic acid solution. This in turn is reacted and neutralized with limestone, thus converting the original CO2 gas to calcium bicarbonate in solution, the overall reaction being:

  8. R&D100: CO2 Memzyme

    SciTech Connect

    Rempe, Susan; Brinker, Jeff; Jiang, Ying-Bing; Vanegas, Juan

    2015-11-19

    By combining a water droplet loaded with CO2 enzymes in an ultrathin nanopore on a flexible substrate, researchers at Sandia National Laboratories realized the first technology that meets and exceeds DOE targets for cost-effective CO2 capture. When compared with the nearest membrane competitor, this technology delivers a three times permeation rate, twenty times higher selectivity, and ten time lower fabrication cost. The CO2 Memzyme has the potential to remove 90% of CO2 emissions and is forecasted to save the U.S. coal industry $90 billion a year compared to conventional technology.

  9. Experimental Ion Mobility measurements in Ne-CO2 and CO2-N2 mixtures

    NASA Astrophysics Data System (ADS)

    Encarnação, P. M. C. C.; Cortez, A. F. V.; Veenhof, R.; Neves, P. N. B.; Santos, F. P.; Trindade, A. M. F.; Borges, F. I. G. M.; Conde, C. A. N.

    2016-05-01

    In this paper we present the experimental results for the mobility, K0, of ions in neon-carbon dioxide (Ne-CO2) and carbon dioxide-nitrogen (CO2-N2) gaseous mixtures for total pressures ranging from 8–12 Torr, reduced electric fields in the 10–25 Td range, at room temperature. Regarding the Ne-CO2 mixture only one peak was observed for CO2 concentrations above 25%, which has been identified as an ion originated in CO2, while below 25% of CO2 a second-small peak appears at the left side of the main peak, which has been attributed to impurities. The mobility values for the main peak range between 3.51 ± 0.05 and 1.07 ± 0.01 cm2V‑1s‑1 in the 10%-99% interval of CO2, and from 4.61 ± 0.19 to 3.00 ± 0.09 cm2V‑1s‑1 for the second peak observed (10%–25% of CO2). For the CO2-N2, the time-of-arrival spectra displayed only one peak for CO2 concentrations above 10%, which was attributed to ions originated in CO2, namely CO2+(CO2), with a second peak appearing for CO2 concentrations below 10%. This second peak, with higher mobility, was attributed to CO2+ ions. The mobility values of the main peak range between 2.11 ± 0.04 and 1.10 ± 0.03 cm2V‑1s‑1 in the 1%–99% interval of CO2, while the second peak's from 2.26 ± 0.02 and 1.95 ± 0.04 cm2V‑1s‑1 (1%–10% of CO2). The inverse of the mobility displays an aproximately linear dependence on the CO2 concentration in the mixture.

  10. Photolytically Generated CO2 on Iapetus

    NASA Astrophysics Data System (ADS)

    Palmer, Eric; Brown, R. H.

    2007-10-01

    The leading edge of Iapetus is covered with a dark material that is carbon rich, suggested to be either a carbonaceous layer (Smith el al 1982), CH4 and NH3 embedded in water ice (Squyres et al 1983), or nitrogen-rich tholin and amorphous carbon (Buratti et al 2005). Laboratory experiments have shown that CO2 can be generated from such material both by photolysis (Allamandola, Sandford & Valero 1988) and radiolysis (Strazzulla & Palumbo 1998). We consider the accumulation of CO2 that could be photolytically generated and sequestered in the polar regions of Iapetus. The polar regions provide only a temporary cold trap for CO2, and any polar cap is expected to be seasonal in nature. Using a numerical model to track the movement of CO2, we find that as CO2 moves between poles, 10% of it would reach escape velocity and be lost from the system every solar orbit (29.46 years). CO2 would accumulate until its loss rate equaled its production rate; thus, the quantity of CO2 in a polar cap would be 10 times the amount produced in a single solar orbit. Provided that the generation of CO2 is large enough, Cassini VIMS would be able to detect a seasonal CO2 polar cap. Since the polar regions are comprised of water ice and do not have the same coating of carbon rich dark material as the dark side, any 4.26 micron band absorption would be CO2 frost rather than complexed CO2.

  11. Capturing CO2 via reactions in nanopores.

    SciTech Connect

    Leung, Kevin; Nenoff, Tina Maria; Criscenti, Louise Jacqueline; Tang, Z; Dong, J. H.

    2008-10-01

    This one-year exploratory LDRD aims to provide fundamental understanding of the mechanism of CO2 scrubbing platforms that will reduce green house gas emission and mitigate the effect of climate change. The project builds on the team member's expertise developed in previous LDRD projects to study the capture or preferential retention of CO2 in nanoporous membranes and on metal oxide surfaces. We apply Density Functional Theory and ab initio molecular dynamics techniques to model the binding of CO2 on MgO and CaO (100) surfaces and inside water-filled, amine group functionalized silica nanopores. The results elucidate the mechanisms of CO2 trapping and clarify some confusion in the literature. Our work identifies key future calculations that will have the greatest impact on CO2 capture technologies, and provides guidance to science-based design of platforms that can separate the green house gas CO2 from power plant exhaust or even from the atmosphere. Experimentally, we modify commercial MFI zeolite membranes and find that they preferentially transmit H2 over CO2 by a factor of 34. Since zeolite has potential catalytic capability to crack hydrocarbons into CO2 and H2, this finding paves the way for zeolite membranes that can convert biofuel into H2 and separate the products all in one step.

  12. CO2 Capture with Enzyme Synthetic Analogue

    SciTech Connect

    Cordatos, Harry

    2010-11-08

    Overview of an ongoing, 2 year research project partially funded by APRA-E to create a novel, synthetic analogue of carbonic anhydrase and incorporate it into a membrane for removal of CO2 from flue gas in coal power plants. Mechanism background, preliminary feasibility study results, molecular modeling of analogue-CO2 interaction, and program timeline are provided.

  13. Mars South Pole CO2 Paleoatmosphere

    NASA Astrophysics Data System (ADS)

    Schneck, T.

    2004-03-01

    Seasonal asymmetry in the CO mixing ratio is explained by condensation of CO_2. High levels of deuteration can be obtained if the gas phase is depleted of CO. UV limbs measurements found intense Cameron band emissions of CO from 1900-2700 A produced by dissociative excitation of CO_2.

  14. CAPTURING CO2 WITH MGO AEROGELS

    EPA Science Inventory

    CO2 capture from flue gas requires that the adsorbent be active at relatively low CO2 concentrations (3 – 13 vol%), high temperatures (~ 250ºC), and in the presence of many other gas species. These conditions will be simulated in the student designed reactor. The...

  15. CO2 ice on Mars: Theoretical simulations

    NASA Technical Reports Server (NTRS)

    Lindner, Bernhard Lee

    1992-01-01

    A theoretical model of the energy budget of the polar caps of Mars has been created which is used to study the hemispherical asymmetry in CO2 ice. The observations which show survival of seasonal CO2 ice in the Southern Hemisphere in summer and not in the Northern Hemisphere in summer have been reproduced.

  16. CO2 Capture with Enzyme Synthetic Analogue

    SciTech Connect

    Cordatos, Harry

    2010-03-01

    Project overview provides background on carbonic anhydrase transport mechanism for CO2 in the human body and proposed approach for ARPA-E project to create a synthetic enzyme analogue and utilize it in a membrane for CO2 capture from flue gas.

  17. Aqueous ethylenediamine for CO(2) capture.

    PubMed

    Zhou, Shan; Chen, Xi; Nguyen, Thu; Voice, Alexander K; Rochelle, Gary T

    2010-08-23

    Aqueous ethylenediamine (EDA) has been investigated as a solvent for CO(2) capture from flue gas. EDA can be used at 12 M (mol kg(-1) H(2)O) with an acceptable viscosity of 16 cP (1 cP=10(-3) Pa s) with 0.48 mol CO(2) per equivalent of EDA. Similar to monoethanolamine (MEA), EDA can be used up to 120 degrees C in a stripper without significant thermal degradation. Inhibitor A will effectively eliminate oxidative degradation. Above 120 degrees C, loaded EDA degrades with the production of its cyclic urea and other related compounds. Unlike piperazine, when exposed to oxidative degradation, EDA does not result in excessive foaming. Over much of the loading range, the CO(2) absorption rate with 12 M EDA is comparable to 7 M MEA. However, at typical rich loading, 12 M EDA absorbs CO(2) 2 times slower than 7 M MEA. The capacity of 12 M EDA is 0.72 mol CO(2)/(kg H(2)O+EDA) (for P(CO(2) )=0.5 to 5 kPa at 40 degrees C), which is about double that of MEA. The apparent heat of CO(2) desorption in EDA solution is 84 kJ mol(-1) CO(2); greater than most other amine systems. PMID:20677204

  18. Improved Criteria for Increasing CO2 Storage Potential with CO2 Enhanced Oil Recovery

    NASA Astrophysics Data System (ADS)

    Bauman, J.; Pawar, R.

    2013-12-01

    In recent years it has been found that deployment of CO2 capture and storage technology at large scales will be difficult without significant incentives. One of the technologies that has been a focus in recent years is CO2 enhanced oil/gas recovery, where additional hydrocarbon recovery provides an economic incentive for deployment. The way CO2 EOR is currently deployed, maximization of additional oil production does not necessarily lead to maximization of stored CO2, though significant amounts of CO2 are stored regardless of the objective. To determine the potential of large-scale CO2 storage through CO2 EOR, it is necessary to determine the feasibility of deploying this technology over a wide range of oil/gas field characteristics. In addition it is also necessary to accurately estimate the ultimate CO2 storage potential and develop approaches that optimize oil recovery along with long-term CO2 storage. This study uses compositional reservoir simulations to further develop technical screening criteria that not only improve oil recovery, but maximize CO2 storage during enhanced oil recovery operations. Minimum miscibility pressure, maximum oil/ CO2 contact without the need of significant waterflooding, and CO2 breakthrough prevention are a few key parameters specific to the technical aspects of CO2 enhanced oil recovery that maximize CO2 storage. We have developed reduced order models based on simulation results to determine the ultimate oil recovery and CO2 storage potential in these formations. Our goal is to develop and demonstrate a methodology that can be used to determine feasibility and long-term CO2 storage potential of CO2 EOR technology.

  19. Venting of CO2 at Enceladus’ Surface

    NASA Astrophysics Data System (ADS)

    Matson, Dennis L.; Davies, Ashley G.; Johnson, Torrence V.; Combe, Jean-Philippe; McCord, Tom B.; Radebaugh, Jani

    2015-11-01

    Enceladus has CO2 surface deposits in its South Polar Region that have been recently mapped by J.-P. Combe et al. (2015 AGU Fall Meeting). Assuming that these are CO2 frost, we show how they can be formed. We use an ocean-water circulation model [1] that specifies pressure gradients that drive water to the surface from a relatively gas-rich, subsurface ocean. We now examine the movement of CO2 to the surface; formation of shallow CO2 gas pockets in the ice; and the venting of CO2, when at least some of the gas freezes to form frost. If the local heat flow is known (cf. [2]), then the depths of the corresponding gas pockets can be calculated. References: [1] Matson et al. (2012) Icarus, 221, 53-62. [2] Howett et al. (2011) J. Geophys. Res. 116, E03003. Acknowledgements: AGD thanks the NASA OPR Program for support.

  20. Zinc depolarized electrochemical CO2 concentration

    NASA Technical Reports Server (NTRS)

    Woods, R. R.; Marshall, R. D.; Schubert, F. H.

    1975-01-01

    Two zinc depolarized electrochemical carbon dioxide concentrator concepts were analytically and experimentally evaluated for portable life support system carbon dioxide (CO2) removal application. The first concept, referred to as the zinc hydrogen generator electrochemical depolarized CO2 concentrator, uses a ZHG to generate hydrogen for direct use in an EDC. The second concept, referred to as the zinc/electrochemical depolarized concentrator, uses a standard EDC cell construction modified for use with the Zn anode. The Zn anode is consumed and subsequently regenerated, thereby eliminating the need to supply H2 to the EDC for the CO2 removal process. The evaluation was based primarily on an analytical evaluation of the two ZnDCs at projected end item performance and hardware design levels. Both ZnDC concepts for PLSS CO2 removal application were found to be noncompetitive in both total equivalent launch weight and individual extravehicular activity mission volume when compared to other candidate regenerable PLSS CO2 scrubbers.

  1. Geophysical monitoring technology for CO2 sequestration

    NASA Astrophysics Data System (ADS)

    Ma, Jin-Feng; Li, Lin; Wang, Hao-Fan; Tan, Ming-You; Cui, Shi-Ling; Zhang, Yun-Yin; Qu, Zhi-Peng; Jia, Ling-Yun; Zhang, Shu-Hai

    2016-06-01

    Geophysical techniques play key roles in the measuring, monitoring, and verifying the safety of CO2 sequestration and in identifying the efficiency of CO2-enhanced oil recovery. Although geophysical monitoring techniques for CO2 sequestration have grown out of conventional oil and gas geophysical exploration techniques, it takes a long time to conduct geophysical monitoring, and there are many barriers and challenges. In this paper, with the initial objective of performing CO2 sequestration, we studied the geophysical tasks associated with evaluating geological storage sites and monitoring CO2 sequestration. Based on our review of the scope of geophysical monitoring techniques and our experience in domestic and international carbon capture and sequestration projects, we analyzed the inherent difficulties and our experiences in geophysical monitoring techniques, especially, with respect to 4D seismic acquisition, processing, and interpretation.

  2. The ins and outs of CO2.

    PubMed

    Raven, John A; Beardall, John

    2016-01-01

    It is difficult to distinguish influx and efflux of inorganic C in photosynthesizing tissues; this article examines what is known and where there are gaps in knowledge. Irreversible decarboxylases produce CO2, and CO2 is the substrate/product of enzymes that act as carboxylases and decarboxylases. Some irreversible carboxylases use CO2; others use HCO3(-). The relative role of permeation through the lipid bilayer versus movement through CO2-selective membrane proteins in the downhill, non-energized, movement of CO2 is not clear. Passive permeation explains most CO2 entry, including terrestrial and aquatic organisms with C3 physiology and biochemistry, terrestrial C4 plants and all crassulacean acid metabolism (CAM) plants, as well as being part of some mechanisms of HCO3(-) use in CO2 concentrating mechanism (CCM) function, although further work is needed to test the mechanism in some cases. However, there is some evidence of active CO2 influx at the plasmalemma of algae. HCO3(-) active influx at the plasmalemma underlies all cyanobacterial and some algal CCMs. HCO3(-) can also enter some algal chloroplasts, probably as part of a CCM. The high intracellular CO2 and HCO3(-) pools consequent upon CCMs result in leakage involving CO2, and occasionally HCO3(-). Leakage from cyanobacterial and microalgal CCMs involves up to half, but sometimes more, of the gross inorganic C entering in the CCM; leakage from terrestrial C4 plants is lower in most environments. Little is known of leakage from other organisms with CCMs, though given the leakage better-examined organisms, leakage occurs and increases the energetic cost of net carbon assimilation. PMID:26466660

  3. The ins and outs of CO2

    PubMed Central

    Raven, John A.; Beardall, John

    2016-01-01

    It is difficult to distinguish influx and efflux of inorganic C in photosynthesizing tissues; this article examines what is known and where there are gaps in knowledge. Irreversible decarboxylases produce CO2, and CO2 is the substrate/product of enzymes that act as carboxylases and decarboxylases. Some irreversible carboxylases use CO2; others use HCO3 –. The relative role of permeation through the lipid bilayer versus movement through CO2-selective membrane proteins in the downhill, non-energized, movement of CO2 is not clear. Passive permeation explains most CO2 entry, including terrestrial and aquatic organisms with C3 physiology and biochemistry, terrestrial C4 plants and all crassulacean acid metabolism (CAM) plants, as well as being part of some mechanisms of HCO3 – use in CO2 concentrating mechanism (CCM) function, although further work is needed to test the mechanism in some cases. However, there is some evidence of active CO2 influx at the plasmalemma of algae. HCO3 – active influx at the plasmalemma underlies all cyanobacterial and some algal CCMs. HCO3 – can also enter some algal chloroplasts, probably as part of a CCM. The high intracellular CO2 and HCO3 – pools consequent upon CCMs result in leakage involving CO2, and occasionally HCO3 –. Leakage from cyanobacterial and microalgal CCMs involves up to half, but sometimes more, of the gross inorganic C entering in the CCM; leakage from terrestrial C4 plants is lower in most environments. Little is known of leakage from other organisms with CCMs, though given the leakage better-examined organisms, leakage occurs and increases the energetic cost of net carbon assimilation. PMID:26466660

  4. Dynamics of CO2 fluxes and concentrations during a shallow subsurface CO2 release

    SciTech Connect

    Lewicki, J.L.; Hilley, G.E.; Dobeck, L.; Spangler, L.

    2009-09-01

    A field facility located in Bozeman, Montana provides the opportunity to test methods to detect, locate, and quantify potential CO2 leakage from geologic storage sites. From 9 July to 7 August 2008, 0.3 t CO2 d{sup -1} were injected from a 100-m long, {approx}2.5 m deep horizontal well. Repeated measurements of soil CO2 fluxes on a grid characterized the spatio-temporal evolution of the surface leakage signal and quantified the surface leakage rate. Infrared CO2 concentration sensors installed in the soil at 30 cm depth at 0 to 10 m from the well and at 4 cm above the ground at 0 and 5 m from the well recorded surface breakthrough of CO2 leakage and migration of CO2 leakage through the soil. Temporal variations in CO2 concentrations were correlated with atmospheric and soil temperature, wind speed, atmospheric pressure, rainfall, and CO2 injection rate.

  5. Effects of CO2 leakage on soil bacterial communities from simulated CO2-EOR areas.

    PubMed

    Chen, Fu; Yang, Yongjun; Ma, Yanjun; Hou, Huping; Zhang, Shaoliang; Ma, Jing

    2016-05-18

    CO2-EOR (enhanced oil recovery) has been proposed as a viable option for flooding oil and reducing anthropogenic CO2 contribution to the atmospheric pool. However, the potential risk of CO2 leakage from the process poses a threat to the ecological system. High-throughput sequencing was used to investigate the effects of CO2 emission on the composition and structure of soil bacterial communities. The diversity of bacterial communities notably decreased with increasing CO2 flux. The composition of bacterial communities varied along the CO2 flux, with increasing CO2 flux accompanied by increases in the relative abundance of Bacteroidetes and Firmicutes phyla, but decreases in the relative abundance of Acidobacteria and Chloroflexi phyla. Within the Firmicutes phylum, the genus Lactobacillus increased sharply when the CO2 flux was at its highest point. Alpha and beta diversity analysis revealed that differences in bacterial communities were best explained by CO2 flux. The redundancy analysis (RDA) revealed that differences in bacterial communities were best explained by soil pH values which related to CO2 flux. These results could be useful for evaluating the risk of potential CO2 leakages on the ecosystems associated with CO2-EOR processes. PMID:27056285

  6. CO2 deserts: implications of existing CO2 supply limitations for carbon management.

    PubMed

    Middleton, Richard S; Clarens, Andres F; Liu, Xiaowei; Bielicki, Jeffrey M; Levine, Jonathan S

    2014-10-01

    Efforts to mitigate the impacts of climate change will require deep reductions in anthropogenic CO2 emissions on the scale of gigatonnes per year. CO2 capture and utilization and/or storage technologies are a class of approaches that can substantially reduce CO2 emissions. Even though examples of this approach, such as CO2-enhanced oil recovery, are already being practiced on a scale >0.05 Gt/year, little attention has been focused on the supply of CO2 for these projects. Here, facility-scale data newly collected by the U.S. Environmental Protection Agency was processed to produce the first comprehensive map of CO2 sources from industrial sectors currently supplying CO2 in the United States. Collectively these sources produce 0.16 Gt/year, but the data reveal the presence of large areas without access to CO2 at an industrially relevant scale (>25 kt/year). Even though some facilities with the capability to capture CO2 are not doing so and in some regions pipeline networks are being built to link CO2 sources and sinks, much of the country exists in "CO2 deserts". A life cycle analysis of the sources reveals that the predominant source of CO2, dedicated wells, has the largest carbon footprint further confounding prospects for rational carbon management strategies. PMID:25137398

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

    PubMed

    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. PMID:27362472

  8. Engineered yeast for enhanced CO2 mineralization†

    PubMed Central

    Barbero, Roberto; Carnelli, Lino; Simon, Anna; Kao, Albert; Monforte, Alessandra d’Arminio; Riccò, Moreno; Bianchi, Daniele; Belcher, Angela

    2014-01-01

    In this work, a biologically catalyzed CO2 mineralization process for the capture of CO2 from point sources was designed, constructed at a laboratory scale, and, using standard chemical process scale-up protocols, was modeled and evaluated at an industrial scale. A yeast display system in Saccharomyces cerevisae was used to screen several carbonic anhydrase isoforms and mineralization peptides for their impact on CO2 hydration, CaCO3 mineralization, and particle settling rate. Enhanced rates for each of these steps in the CaCO3 mineralization process were confirmed using quantitative techniques in lab-scale measurements. The effect of these enhanced rates on the CO2 capture cost in an industrial scale CO2 mineralization process using coal fly ash as the CaO source was evaluated. The model predicts a process using bCA2- yeast and fly ash is ~10% more cost effective per ton of CO2 captured than a process with no biological molecules, a savings not realized by wild-type yeast and high-temperature stable recombinant CA2 alone or in combination. The levelized cost of electricity for a power plant using this process was calculated and scenarios in which this process compares favorably to CO2 capture by MEA absorption process are presented. PMID:25289021

  9. Glacial CO2 Cycles: A Composite Scenario

    NASA Astrophysics Data System (ADS)

    Broecker, W. S.

    2015-12-01

    There are three main contributors to the glacial drawdown of atmospheric CO2 content: starvation of the supply of carbon to the ocean-atmosphere reservoir, excess CO2 storage in the deep sea, and surface-ocean cooling. In this talk, I explore a scenario in which all three play significant roles. Key to this scenario is the assumption that deep ocean storage is related to the extent of nutrient stratification of the deep Atlantic. The stronger this stratification, the larger the storage of respiration CO2. Further, it is my contention that the link between Milankovitch insolation cycles and climate is reorganizations of the ocean's thermohaline circulation leading to changes in the deep ocean's CO2 storage. If this is the case, the deep Atlantic d13C record kept in benthic foraminifera shells tells us that deep ocean CO2 storage follows Northern Hemisphere summer insolation cycles and thus lacks the downward ramp so prominent in the records of sea level, benthic 18O and CO2. Rather, the ramp is created by the damping of planetary CO2 emissions during glacial time intervals. As it is premature to present a specific scenario, I provide an example as to how these three contributors might be combined. As their magnitudes and shapes remain largely unconstrained, the intent of this exercise is to provoke creative thinking.

  10. Regenerable Sorbent for CO2 Removal

    NASA Technical Reports Server (NTRS)

    Alptekin, Gokhan; Jayaraman, Ambal

    2013-01-01

    A durable, high-capacity regenerable sorbent can remove CO2 from the breathing loop under a Martian atmosphere. The system design allows near-ambient temperature operation, needs only a small temperature swing, and sorbent regeneration takes place at or above 8 torr, eliminating the potential for Martian atmosphere to leak into the regeneration bed and into the breathing loop. The physical adsorbent can be used in a metabolic, heat-driven TSA system to remove CO2 from the breathing loop of the astronaut and reject it to the Martian atmosphere. Two (or more) alternating sorbent beds continuously scrub and reject CO2 from the spacesuit ventilation loop. The sorbent beds are cycled, alternately absorbing CO2 from the vent loop and rejecting the adsorbed material into the environment at a high CO2 partial pressure (above 8 torr). The system does not need to run the adsorber at cryogenic temperatures, and uses a much smaller temperature swing. The sorbent removes CO2 via a weak chemical interaction. The interaction is strong enough to enable CO2 adsorption even at 3 to 7.6 torr. However, because the interaction between the surface adsorption sites and the CO2 is relatively weak, the heat input needed to regenerate the sorbent is much lower than that for chemical absorbents. The sorbent developed in this project could potentially find use in a large commercial market in the removal of CO2 emissions from coal-fired power plants, if regulations are put in place to curb carbon emissions from power plants.

  11. Estimating lake-atmosphere CO2 exchange

    USGS Publications Warehouse

    Anderson, D.E.; Striegl, R.G.; Stannard, D.I.; Michmerhuizen, C.M.; McConnaughey, T.A.; LaBaugh, J.W.

    1999-01-01

    Lake-atmosphere CO2 flux was directly measured above a small, woodland lake using the eddy covariance technique and compared with fluxes deduced from changes in measured lake-water CO2 storage and with flux predictions from boundary-layer and surface-renewal models. Over a 3-yr period, lake-atmosphere exchanges of CO2 were measured over 5 weeks in spring, summer, and fall. Observed springtime CO2 efflux was large (2.3-2.7 ??mol m-2 s-1) immediately after lake-thaw. That efflux decreased exponentially with time to less than 0.2 ??mol m-2 s-1 within 2 weeks. Substantial interannual variability was found in the magnitudes of springtime efflux, surface water CO2 concentrations, lake CO2 storage, and meteorological conditions. Summertime measurements show a weak diurnal trend with a small average downward flux (-0.17 ??mol m-2 s-1) to the lake's surface, while late fall flux was trendless and smaller (-0.0021 ??mol m-2 s-1). Large springtime efflux afforded an opportunity to make direct measurement of lake-atmosphere fluxes well above the detection limits of eddy covariance instruments, facilitating the testing of different gas flux methodologies and air-water gas-transfer models. Although there was an overall agreement in fluxes determined by eddy covariance and those calculated from lake-water storage change in CO2, agreement was inconsistent between eddy covariance flux measurements and fluxes predicted by boundary-layer and surface-renewal models. Comparison of measured and modeled transfer velocities for CO2, along with measured and modeled cumulative CO2 flux, indicates that in most instances the surface-renewal model underpredicts actual flux. Greater underestimates were found with comparisons involving homogeneous boundary-layer models. No physical mechanism responsible for the inconsistencies was identified by analyzing coincidentally measured environmental variables.

  12. Geological factors affecting CO2 plume distribution

    USGS Publications Warehouse

    Frailey, S.M.; Leetaru, H.

    2009-01-01

    Understanding the lateral extent of a CO2 plume has important implications with regards to buying/leasing pore volume rights, defining the area of review for an injection permit, determining the extent of an MMV plan, and managing basin-scale sequestration from multiple injection sites. The vertical and lateral distribution of CO2 has implications with regards to estimating CO2 storage volume at a specific site and the pore pressure below the caprock. Geologic and flow characteristics such as effective permeability and porosity, capillary pressure, lateral and vertical permeability anisotropy, geologic structure, and thickness all influence and affect the plume distribution to varying degrees. Depending on the variations in these parameters one may dominate the shape and size of the plume. Additionally, these parameters do not necessarily act independently. A comparison of viscous and gravity forces will determine the degree of vertical and lateral flow. However, this is dependent on formation thickness. For example in a thick zone with injection near the base, the CO2 moves radially from the well but will slow at greater radii and vertical movement will dominate. Generally the CO2 plume will not appreciably move laterally until the caprock or a relatively low permeability interval is contacted by the CO2. Conversely, in a relatively thin zone with the injection interval over nearly the entire zone, near the wellbore the CO2 will be distributed over the entire vertical component and will move laterally much further with minimal vertical movement. Assuming no geologic structure, injecting into a thin zone or into a thick zone immediately under a caprock will result in a larger plume size. With a geologic structure such as an anticline, CO2 plume size may be restricted and injection immediately below the caprock may have less lateral plume growth because the structure will induce downward vertical movement of the CO2 until the outer edge of the plume reaches a spill

  13. Natural Analog for Geologic Storage of CO2: CO2 accumulation in China

    NASA Astrophysics Data System (ADS)

    Liu, L.; Xu, T.; Liu, N.; Zhou, B.

    2012-12-01

    Natural accumulations of CO2 are potential analogues of CO2 geological storage that can provide useful information on the behaviour of supercritical CO2 in reservoirs. Natural CO2 accumulations are common across Northeast China, and, although they occur in a wide variety of geological settings, their distribution is principally controlled by the Mesozoic-Cenozoic rift basins and associated Quaternary volcanism. High CO2 concentrations (>60 CO2%) in natural gas reservoirs are usually related to volcanism and magmatism, and possesses mantle-genetic origin. CO2 reservoirs consist of sandstone, volcanic rocks and carbonate rocks with the buried depth from 2000-3000 m. Dawsonite is recognized in almost all of the CO2-bearing basin, which has been proved to share the same carbon source with CO2 in the reservoirs in Songliao basin, Hailaer basin and Donghai basin. Petrographic data show that dawsonite is abundant in feldspar- rich sandstone, volcanic rock fragment-rich sandstones and tuff. In some cases, high percentage of dawsonite cement constitutes a diagenetic seal, which occurs in the reservoir-mudstone caprock and prevents upward leakage of CO2. Besides dawsonite, mantle-genetic CO2 flux leads to the formation of calcite, ankerite and siderite. The statistics of porosity and permeability measured from the dawsonite-bearing sandstone and dawsonite-absent sandstone with the almost same burial depth in Songliao basin show that the mantle-genetic CO2 flux result in lower reservoir quality, suggesting that mineral trapping for CO2 is significant. Chemical analyses of formation water in Songliao basin and Hailaer basin indicate that the concentrations of TDS, HCO3-,CO32-, Mg2+,Ca2+ and Na+ + K+ in dawsonite-bearing sandstone are higher than that in dawsonite-absent sandstone. Distribution of CO2 and dawsonite is constrainted by the regional caprocks in the Songliao basin. The charging time of the mantle-genetic CO2 in China dates from 50 to 25 Ma.

  14. The Oceanic Sink for Anthropogenic CO2

    SciTech Connect

    Sabine, Chris; Feely, R. A.; Gruber, N.; Key, Robert; Lee, K.; Bullister, J.L.; Wanninkhof, R.; Wong, C. S.; Wallace, D.W.R.; Tilbrook, B.; Millero, F. J.; Peng, T.-H.; Kozyr, Alexander; Ono, Tsueno

    2004-01-01

    Using inorganic carbon measurements from an international survey effort in the 1990s and a tracer-based separation technique, we estimate a global oceanic anthropogenic carbon dioxide (CO2) sink for the period from 1800 to 1994 of 118 19 petagrams of carbon. The oceanic sink accounts for ~48% of the total fossil-fuel and cement-manufacturing emissions, implying that the terrestrial biosphere was a net source of CO2 to the atmosphere of about 39 28 petagrams of carbon for this period. The current fraction of total anthropogenic CO2 emissions stored in the ocean appears to be about one-third of the long-term potential.

  15. Atmospheric CO2 Removal by Enhancing Weathering

    NASA Astrophysics Data System (ADS)

    Koster van Groos, A. F.; Schuiling, R. D.

    2014-12-01

    The increase of the CO2 content in the atmosphere by the release of anthropogenic CO2 may be addressed by the enhancement of weathering at the surface of the earth. The average emission of mantle-derived CO2 through volcanism is ~0.3 Gt/year (109 ton/year). Considering the ~3.000 Gt of CO2 present in the atmosphere, the residence time of CO2 in the earth's atmosphere is ~10,000 years. Because the vast proportion of carbon in biomass is recycled through the atmosphere, CO2 is continuously removed by a series of weathering reactions of silicate minerals and stored in calcium and magnesium carbonates. The addition of anthropogenic CO2 from fossil fuel and cement production, which currently exceeds 35 Gt/year and dwarfs the natural production 100-fold, cannot be compensated by current rates of weathering, and atmospheric CO2 levels are rising rapidly. To address this increase in CO2 levels, weathering rates would have to be accelerated on a commensurate scale. Olivine ((Mg,Fe)2SiO4) is the most reactive silicate mineral in the weathering process. This mineral is the major constituent in relatively common ultramafic rocks such as dunites (olivine content > 90%). To consume the current total annual anthropogenic release of CO2, using a simplified weathering reaction (Mg2SiO4 + 4CO2 + 4H2O --> 2 Mg2+ + 4HCO3- + H4SiO4) would require ~30 Gt/year or ~8-9 km3/year of dunite. This is a large volume; it is about double the total amount of ore and gravel currently mined (~ 17 Gt/year). To mine and crush these rocks to <100 μm costs ~ 8/ton. The transport and distribution over the earth's surface involves additional costs, that may reach 2-5/ton. Thus, the cost of remediation for the release of anthropogenic CO2 is 300-400 billion/year. This compares to a 2014 global GDP of ~80 trillion. Because weathering reactions require the presence of water and proceed more rapidly at higher temperatures, the preferred environments to enhance weathering are the wet tropics. From a socio

  16. CO2 Sensing and CO2 Regulation of Stomatal Conductance: Advances and Open Questions.

    PubMed

    Engineer, Cawas B; Hashimoto-Sugimoto, Mimi; Negi, Juntaro; Israelsson-Nordström, Maria; Azoulay-Shemer, Tamar; Rappel, Wouter-Jan; Iba, Koh; Schroeder, Julian I

    2016-01-01

    Guard cells form epidermal stomatal gas-exchange valves in plants and regulate the aperture of stomatal pores in response to changes in the carbon dioxide (CO2) concentration ([CO2]) in leaves. Moreover, the development of stomata is repressed by elevated CO2 in diverse plant species. Evidence suggests that plants can sense [CO2] changes via guard cells and via mesophyll tissues in mediating stomatal movements. We review new discoveries and open questions on mechanisms mediating CO2-regulated stomatal movements and CO2 modulation of stomatal development, which together function in the CO2 regulation of stomatal conductance and gas exchange in plants. Research in this area is timely in light of the necessity of selecting and developing crop cultivars that perform better in a shifting climate. PMID:26482956

  17. Partitioning of the Leaf CO2 Exchange into Components Using CO2 Exchange and Fluorescence Measurements.

    PubMed

    Laisk, A.; Sumberg, A.

    1994-10-01

    Photorespiration was calculated from chlorophyll fluorescence and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) kinetics and compared with CO2 evolution rate in the light, measured by three gas-exchange methods in mature sunflower (Helianthus annuus L.) leaves. The gas-exchange methods were (a) postillumination CO2 burst at unchanged CO2 concentration, (b) postillumination CO2 burst with simultaneous transfer into CO2-free air, and (c) extrapolation of the CO2 uptake to zero CO2 concentration at Rubisco active sites. The steady-state CO2 compensation point was proportional to O2 concentration, revealing the Rubisco specificity coefficient (Ksp) of 86. Electron transport rate (ETR) was calculated from fluorescence, and photorespiration rate was calculated from ETR using CO2 and O2 concentrations, Ksp, and diffusion resistances. The values of the best-fit mesophyll diffusion resistance for CO2 ranged between 0.3 and 0.8 s cm-1. Comparison of the gas-exchange and fluorescence data showed that only ribulose-1,5-bisphosphate (RuBP) carboxylation and photorespiratory CO2 evolution were present at limiting CO2 concentrations. Carboxylation of a substrate other than RuBP, in addition to RuBP carboxylation, was detected at high CO2 concentrations. A simultaneous decarboxylation process not related to RuBP oxygenation was also detected at high CO2 concentrations in the light. We propose that these processes reflect carboxylation of phosphoenolpyruvate, formed from phosphoglyceric acid and the subsequent decarboxylation of malate. PMID:12232361

  18. How secure is subsurface CO2 storage? Controls on leakage in natural CO2 reservoirs

    NASA Astrophysics Data System (ADS)

    Miocic, Johannes; Gilfillan, Stuart; McDermott, Christopher; Haszeldine, Stuart

    2014-05-01

    Carbon Capture and Storage (CCS) is the only industrial scale technology available to directly reduce carbon dioxide (CO2) emissions from fossil fuelled power plants and large industrial point sources to the atmosphere. The technology includes the capture of CO2 at the source and transport to subsurface storage sites, such as depleted hydrocarbon reservoirs or saline aquifers, where it is injected and stored for long periods of time. To have an impact on the greenhouse gas emissions it is crucial that there is no or only a very low amount of leakage of CO2 from the storage sites to shallow aquifers or the surface. CO2 occurs naturally in reservoirs in the subsurface and has often been stored for millions of years without any leakage incidents. However, in some cases CO2 migrates from the reservoir to the surface. Both leaking and non-leaking natural CO2 reservoirs offer insights into the long-term behaviour of CO2 in the subsurface and on the mechanisms that lead to either leakage or retention of CO2. Here we present the results of a study on leakage mechanisms of natural CO2 reservoirs worldwide. We compiled a global dataset of 49 well described natural CO2 reservoirs of which six are leaking CO2 to the surface, 40 retain CO2 in the subsurface and for three reservoirs the evidence is inconclusive. Likelihood of leakage of CO2 from a reservoir to the surface is governed by the state of CO2 (supercritical vs. gaseous) and the pressure in the reservoir and the direct overburden. Reservoirs with gaseous CO2 is more prone to leak CO2 than reservoirs with dense supercritical CO2. If the reservoir pressure is close to or higher than the least principal stress leakage is likely to occur while reservoirs with pressures close to hydrostatic pressure and below 1200 m depth do not leak. Additionally, a positive pressure gradient from the reservoir into the caprock averts leakage of CO2 into the caprock. Leakage of CO2 occurs in all cases along a fault zone, indicating that

  19. Study on CO2 global recycling system.

    PubMed

    Takeuchi, M; Sakamoto, Y; Niwa, S

    2001-09-28

    In order to assist in finding ways to mitigate CO2 emission and to slow the depletion of fossil fuels we have established and evaluated a representative system, which consists of three technologies developed in our laboratory. These technologies were in CO2 recovery, hydrogen production and methanol synthesis and in addition we established the necessary supporting systems. Analysis of outline designs of the large scale renewable energy power generation system and this system and energy input for building plant, energy input for running plant has been conducted based on a case using this system for a 1000-MW coal fired power plant, followed by an evaluation of the material balance and energy balance. The results are as follows. Energy efficiency is 34%, the CO2 reduction rate is 41%, the balance ratio of the energy and CO2 of the system is 2.2 and 1.8, respectively, on the assumption that the primary renewable energy is solar thermal power generation, the stationary CO2 emission source is a coal-fired power plant and the generation efficiency of the methanol power plant is 60%. By adopting the system, 3.7 million tons of CO2 can be recovered, approximately 2.7 million tons of methanol can be produced, and 15.4 billion kWh of electricity can be generated per year. Compared to generating all electrical power using only coal, approximately 2.6 million tons of coal per year can be saved and approximately 2.15 million tons of CO2 emission can be reduced. Therefore, it is clearly revealed that this system would be effective to reduce CO2 emissions and to utilize renewable energy. PMID:11589395

  20. Mechanisms of CO2 Interaction with Montmorillonite

    NASA Astrophysics Data System (ADS)

    Romanov, V.; Myshakin, E. M.; Howard, B.; Guthrie, G.

    2013-12-01

    Improved understanding of basic fluid-rock interactions can lead to more accurate models of the coupled fluid-flow and geomechanics in engineered geological systems. We studied carbon dioxide (CO2) interaction with source clay samples from The Clay Minerals Society. The manometric, infrared (IR) and X-ray diffraction (XRD) data indicated that montmorillonite can permanently trap CO2 molecules in its interlayer, after dynamic exposure to supercritical CO2. Such trapping is quite secure and appears to result in partial carbonate formation. Molecular dynamics simulations were carried out to investigate CO2 intercalation into the interlayer and its interaction with interlayer species. Previously reported results of simulations using simplified smectite models suggested that the experimentally observed red shift of the asymmetric-stretch vibrational mode for the trapped carbon dioxide can be attributed to induced polarization of the CO2 molecule by the interlayer water molecules. Modified smectite models were designed to account for the naturally occurring structural disorder that allows guest molecules to occupy localized interlamellar voids. In such models, energy dependences and structural rearrangements of the interlayer species are governed by rotational misalignment in turbostratically disordered clay. CO2 invasion in the interlayer disrupts the long-range ordering of water molecules and cations thus forcing the system to adopt energetically unfavorable configurations. New findings indicate that interaction between intercalated CO2 and H2O is limited and, with the increasing interlayer hydration, CO2 preferentially accumulates in interlamellar voids. The vibrational spectra produced by the new model, assuming that clay systems can exist in fractional hydration states, show either a combination of undisturbed and red-shifted asymmetric-stretch modes or a broad peak consistent with the multiple smeared peaks, which explain the multi-mode features that have appeared

  1. The overlooked tropical oceanic CO2 sink

    NASA Astrophysics Data System (ADS)

    Ibánhez, J. Severino P.; Araujo, Moacyr; Lefèvre, Nathalie

    2016-04-01

    The intense rainfall in the tropical Atlantic spatially overlaps with the spread of the Amazon plume. Based on remote-sensed sea surface salinity and rainfall, we removed the contribution of rainfall to the apparent Amazon plume area, thus refining the quantification of its extension (0.84 ± 0.06 × 106 km2 to 0.89 ± 0.06 × 106 km2). Despite the previous overestimation of the Amazon plume area due to the influence of rainfall (>16%), our calculated annual CO2 flux based on rainfall-corrected sea surface CO2 fugacity confirms that the Amazon River plume is an atmospheric CO2 sink of global importance (-7.61 ± 1.01 to -7.85 ± 1.02 Tg C yr-1). Yet we show that current sea-air CO2 flux assessments for the tropical Atlantic could be overestimated in about 10% by neglecting the CO2 sink associated to the Amazon plume. Thus, including the Amazon plume, the sea-air CO2 exchange for the tropical Atlantic is estimated to be 81.1 ± 1.1 to 81.5 ± 1.1 Tg C yr-1.

  2. CO2 As An Inverse Greenhouse Gas

    NASA Astrophysics Data System (ADS)

    Idso, Sherwood B.

    1984-01-01

    It is a well-known fact that mankind's burning of fossil fuels such as coal, gas and oil has significantly increased the CO2 content of Earth's atmosphere, from something less than 300 ppm (parts per million by volume) in the pre-Industrial Revolution era to a con-centration which is currently somewhat over 340 ppm. It is also fairly well established that a concentration of 600 ppm will be reached sometime in the next century. Atmospheric scientists using complex computer models of the atmosphere have predicted that such a concentration doubling will lead to a calamatous climatic warming, due to the thermal infra-red "greenhouse" properties of CO2. However, my investigation of a large body of empirical evidence suggests just the opposite. Indeed, long-term records of surface air temperature and snow cover data indicate that increasing concentrations of atmospheric CO2 may actually tend to cool the Earth and not warm it. These and other observations of the real world lead to the conclusion that, for the present composition of the Earth's atmosphere, CO2 appears to behave as an inverse greenhouse gas. A mechanism for this phenomenon is suggested; and it is then indicated how enhanced concentrations of atmospheric CO2 may be beneficial for the planet, particularly with respect to the ability of enhanced CO2 concentrations to stimulate plant growth and reduce water requirements.

  3. CO2 cooling in terrestrial planet thermospheres

    NASA Technical Reports Server (NTRS)

    Bougher, S. W.; Hunten, D. M.; Roble, R. G.

    1994-01-01

    We examine the recent progress in the debate on the CO2-O relaxation rate, its temperature dependence, and its corresponding impact on the thermospheric heat budgets of Venus, Earth, and Mars. This comparative approach provides the broadest range of conditions under which a common CO2-O relaxation rate should provide consistent results. New global mean calculations are presented for the heat budgets of these three planets using large CO2-O relaxation rates that have been inferred recently from Earth CO2 radiance measurements and laboratory studies. Results indicate that available Venus and Mars data constrain the CO2-O relaxation rate to be 2-4 x 10(exp -12)/cu cm/s at 300 K. For Venus, this strong cooling serves as an effective thermostat that gives rise to a small variation of thermospheric temperatures over the solar cycle, just as observed. Conversely, CO2 cooling does not appear to be dominant in the dayside heat budget of the Mars thermosphere over most of the solar cycle. For the Earth, this strong cooling implies that the lower thermosphere does not typically require significant eddy diffusion or heat conduction. However, global-scale dynamics or an additional heating mechanism may be needed to restore calculated temperatures to observed values when relaxation rates exceeding 2 x 10(exp -12)/cu cm/s are employed.

  4. CO2 Absorption Spectroscopy and Climate Change

    NASA Astrophysics Data System (ADS)

    Feldman, Daniel; Mlawer, Eli; Mlynczak, Martin; Gero, Jon; Collins, William; Torn, Margaret

    2014-03-01

    Most of the absorption, and therefore radiative forcing, due to increased atmospheric CO2 occurs in line wings, so utilizing an accurate line shape is necessary for climate science. Recent advances in CO2 absorption spectroscopy have been incorporated into benchmark line-by-line radiative transfer models. These updates include the Energy Corrected Sudden Approximation to represent isolated line profiles, line mixing, and line clusters. The CO2 line profiles are sub-Lorentzian and are explicitly modeled up to 25 cm-1 from each line's center. Consistent continuum absorption is implemented over the remainder of the profile except for modest empirical adjustments based on observations. Thus, line-by-line models calculate the absorption effects of CO2 that agree with theory and measurements. This is validated with long-term spectroscopic measurements from the ARM program's AERI instrument. This spectroscopy trains computationally-efficient correlated-k methods for climate model radiative transfer, but they overpredict instantaneous radiative forcing from doubled CO2 by approximately 7% in part because they have larger errors handling the impact of increased CO2 in the stratosphere than the troposphere. The implications of this can be tested with supercomputers. This work was supported by the Director, Office of Science, Office of Biol. & Env. Res., Clim. & Env. Sci. Div., of the U.S. D.O.E., Contract No. DE-AC02-05CH11231 as part of the Atmos. Sys. Res.

  5. CO2 Efflux from Cleared Mangrove Peat

    PubMed Central

    Lovelock, Catherine E.; Ruess, Roger W.; Feller, Ilka C.

    2011-01-01

    Background CO2 emissions from cleared mangrove areas may be substantial, increasing the costs of continued losses of these ecosystems, particularly in mangroves that have highly organic soils. Methodology/Principal Findings We measured CO2 efflux from mangrove soils that had been cleared for up to 20 years on the islands of Twin Cays, Belize. We also disturbed these cleared peat soils to assess what disturbance of soils after clearing may have on CO2 efflux. CO2 efflux from soils declines from time of clearing from ∼10 600 tonnes km−2 year−1 in the first year to 3000 tonnes km2 year−1 after 20 years since clearing. Disturbing peat leads to short term increases in CO2 efflux (27 umol m−2 s−1), but this had returned to baseline levels within 2 days. Conclusions/Significance Deforesting mangroves that grow on peat soils results in CO2 emissions that are comparable to rates estimated for peat collapse in other tropical ecosystems. Preventing deforestation presents an opportunity for countries to benefit from carbon payments for preservation of threatened carbon stocks. PMID:21738628

  6. Density of aqueous solutions of CO2

    SciTech Connect

    Garcia, Julio E.

    2001-10-10

    In this report, we present a numerical representation for the partial molar volume of CO2 in water and the calculation of the corresponding aqueous solution density. The motivation behind this work is related to the importance of having accurate representations for aqueous phase properties in the numerical simulation of carbon dioxide disposal into aquifers as well as in geothermal applications. According to reported experimental data the density of aqueous solutions of CO2 can be as much as 2-3% higher than pure water density. This density variation might produce an influence on the groundwater flow regime. For instance, in geologic sequestration of CO2, convective transport mixing might occur when, several years after injection of carbon dioxide has stopped, the CO2-rich gas phase is concentrated at the top of the formation, just below an overlaying caprock. In this particular case the heavier CO2 saturated water will flow downward and will be replaced by water with a lesser CO2 content.

  7. Advanced CO2 Removal and Reduction System

    NASA Technical Reports Server (NTRS)

    Alptekin, Gokhan; Dubovik, Margarita; Copeland, Robert J.

    2011-01-01

    An advanced system for removing CO2 and H2O from cabin air, reducing the CO2, and returning the resulting O2 to the air is less massive than is a prior system that includes two assemblies . one for removal and one for reduction. Also, in this system, unlike in the prior system, there is no need to compress and temporarily store CO2. In this present system, removal and reduction take place within a single assembly, wherein removal is effected by use of an alkali sorbent and reduction is effected using a supply of H2 and Ru catalyst, by means of the Sabatier reaction, which is CO2 + 4H2 CH4 + O2. The assembly contains two fixed-bed reactors operating in alternation: At first, air is blown through the first bed, which absorbs CO2 and H2O. Once the first bed is saturated with CO2 and H2O, the flow of air is diverted through the second bed and the first bed is regenerated by supplying it with H2 for the Sabatier reaction. Initially, the H2 is heated to provide heat for the regeneration reaction, which is endothermic. In the later stages of regeneration, the Sabatier reaction, which is exothermic, supplies the heat for regeneration.

  8. CO2 Acquisition Membrane (CAM) Project

    NASA Technical Reports Server (NTRS)

    Mason, Larry W.

    2003-01-01

    The CO2 Acquisition Membrane (CAM) project was performed to develop, test, and analyze thin film membrane materials for separation and purification of carbon dioxide (CO2) from mixtures of gases, such as those found in the Martian atmosphere. The membranes developed in this project are targeted toward In Situ Resource Utilization (ISRU) applications, such as In Situ Propellant Production (ISPP) and In Situ Consumables Production (ISCP). These membrane materials may be used in a variety of ISRU systems, for example as the atmospheric inlet filter for an ISPP process to enhance the concentration of CO2 for use as a reactant gas, to passively separate argon and nitrogen trace gases from CO2 for habitat pressurization, to provide a system for removal of CO2 from breathing gases in a closed environment, or within a process stream to selectively separate CO2 from other gaseous components. The membranes identified and developed for CAM were evaluated for use in candidate ISRU processes and other gas separation applications, and will help to lay the foundation for future unmanned sample return and human space missions. CAM is a cooperative project split among three institutions: Lockheed Martin Astronautics (LMA), the Colorado School of Mines (CSM), and Marshall Space Flight Center (MSFC).

  9. Global CO2 simulation using GOSAT-based surface CO2 flux estimates

    NASA Astrophysics Data System (ADS)

    Takagi, H.; Oda, T.; Saito, M.; Valsala, V.; Belikov, D.; Saeki, T.; Saito, R.; Morino, I.; Uchino, O.; Yoshida, Y.; Yokota, Y.; Bril, A.; Oshchepkov, S.; Andres, R. J.; Maksyutov, S.

    2012-04-01

    Investigating the distribution and temporal variability of surface CO2 fluxes is an active research topic in the field of contemporary carbon cycle dynamics. The technique central to this effort is atmospheric inverse modeling with which surface CO2 fluxes are estimated by making corrections to a priori flux estimates such that mismatches between model-predicted and observed CO2 concentrations are minimized. Past investigations were carried out by utilizing CO2 measurements collected in global networks of surface-based monitoring sites. Now, datasets of column-averaged CO2 dry air mole fraction (XCO2) retrieved from spectral soundings collected by GOSAT are available for complementing the surface-based CO2 observations. These space-based XCO2 data are expected to enhance the spatiotemporal coverage of the existing surface observation network and thus reduce uncertainty associated with the surface flux estimates. We estimated monthly CO2 fluxes in 64 sub-continental regions from a subset of the surface-based GLOBALVIEW CO2 data and the GOSAT FTS SWIR Level 2 XCO2 retrievals. We further simulated CO2 concentrations in 3-D model space using the surface flux estimates obtained. In this presentation, we report the result of a comparison between the simulated CO2 concentrations and independent surface observations. As part of an effort in inter-comparing GOSAT-based surface CO2 flux estimates, we also look at results yielded with XCO2 data retrieved with the PPDF-DOAS algorithm and those made available by the NASA Atmospheric CO2 Observations from Space team. For this study, we used version 08.1 of the National Institute for Environmental Studies atmospheric transport model, which was driven by the Japan Meteorological Agency's JCDAS wind analysis data. The CO2 forward simulations were performed on 2.5° × 2.5° horizontal grids at 32 vertical levels between the surface and the top of the atmosphere. The a priori flux dataset used was comprised of the sum of four

  10. Modeling CO2 Gas Migration of Shallow Subsurface CO2 Leakage Experiments

    NASA Astrophysics Data System (ADS)

    Porter, M. L.; Plampin, M. R.; Pawar, R.; Illangasekare, T. H.

    2013-12-01

    Leakage of injected CO2 into shallow subsurface aquifers or back into the atmosphere at geologic carbon sequestration sites is a risk that must be minimized. One potential CO2 leakage pathway involves the transport of dissolved CO2 into a shallow aquifer where the CO2 exsolves, forming a free CO2 gas phase that subsequently migrates through the aquifer. In order to reduce the negative effects of CO2 exsolution, it is important to fully understand each of the processes controlling the movement CO2, as well as the effects of aquifer heterogeneity on the overall fate and transport of CO2. In this work, we present multiphase flow simulations of intermediate scale CO2 exsolution experiments. The multiphase flow simulations were carried out using the Finite Element Heat and Mass Transfer code (FEHM) developed at Los Alamos National Laboratory. Simulations were first designed to model experiments conducted in two different homogeneous packed sands. PEST (Parameter Estimation and Uncertainty Analysis) was used to optimize multiphase flow parameters (i.e., porosity, permeability, relative permeability, and capillary pressure) within FEHM. The optimized parameters were subsequently used to model heterogeneous experiments consisting of various packing configurations using the same sands. Comparisons of CO2 saturation between experiments and simulations will be presented and analyzed.

  11. Fingerprinting captured CO2 using natural tracers: Determining CO2 fate and proving ownership

    NASA Astrophysics Data System (ADS)

    Flude, Stephanie; Gilfillan, Stuart; Johnston, Gareth; Stuart, Finlay; Haszeldine, Stuart

    2016-04-01

    In the long term, captured CO2 will most likely be stored in large saline formations and it is highly likely that CO2 from multiple operators will be injected into a single saline formation. Understanding CO2 behavior within the reservoir is vital for making operational decisions and often uses geochemical techniques. Furthermore, in the event of a CO2 leak, being able to identify the owner of the CO2 is of vital importance in terms of liability and remediation. Addition of geochemical tracers to the CO2 stream is an effective way of tagging the CO2 from different power stations, but may become prohibitively expensive at large scale storage sites. Here we present results from a project assessing whether the natural isotopic composition (C, O and noble gas isotopes) of captured CO2 is sufficient to distinguish CO2 captured using different technologies and from different fuel sources, from likely baseline conditions. Results include analytical measurements of CO2 captured from a number of different CO2 capture plants and a comprehensive literature review of the known and hypothetical isotopic compositions of captured CO2 and baseline conditions. Key findings from the literature review suggest that the carbon isotope composition will be most strongly controlled by that of the feedstock, but significant fractionation is possible during the capture process; oxygen isotopes are likely to be controlled by the isotopic composition of any water used in either the industrial process or the capture technology; and noble gases concentrations will likely be controlled by the capture technique employed. Preliminary analytical results are in agreement with these predictions. Comparison with summaries of likely storage reservoir baseline and shallow or surface leakage reservoir baseline data suggests that C-isotopes are likely to be valuable tracers of CO2 in the storage reservoir, while noble gases may be particularly valuable as tracers of potential leakage.

  12. Leaf cavity CO2 concentrations and CO2 exchange in onion, Allium cepa L.

    PubMed

    Byrd, G T; Loboda, T; Black, C C; Brown, R H

    1995-06-01

    Onion (Allium cepa L.) plants were examined to determine the photosynthetic role of CO2 that accumulates within their leaf cavities. Leaf cavity CO2 concentrations ranged from 2250 μL L(-1) near the leaf base to below atmospheric (<350 μL L(-1)) near the leaf tip at midday. There was a daily fluctuation in the leaf cavity CO2 concentrations with minimum values near midday and maximum values at night. Conductance to CO2 from the leaf cavity ranged from 24 to 202 μmol m(-2) s(-1) and was even lower for membranes of bulb scales. The capacity for onion leaves to recycle leaf cavity CO2 was poor, only 0.2 to 2.2% of leaf photosynthesis based either on measured CO2 concentrations and conductance values or as measured directly by (14)CO2 labeling experiments. The photosynthetic responses to CO2 and O2 were measured to determine whether onion leaves exhibited a typical C3-type response. A linear increase in CO2 uptake was observed in intact leaves up to 315 μL L(-1) of external CO2 and, at this external CO2 concentration, uptake was inhibited 35.4±0.9% by 210 mL L(-1) O2 compared to 20 mL L(-1) O2. Scanning electron micrographs of the leaf cavity wall revealed degenerated tissue covered by a membrane. Onion leaf cavity membranes apparently are highly impermeable to CO2 and greatly restrict the refixation of leaf cavity CO2 by photosynthetic tissue. PMID:24307095

  13. Precursory volcanic CO2 signals from space

    NASA Astrophysics Data System (ADS)

    Schwandner, Florian M.; Carn, Simon A.; Kataoka, Fumie; Kuze, Akihiko; Shiomi, Kei; Goto, Naoki

    2016-04-01

    Identification of earliest signals heralding volcanic unrest benefits from the unambiguous detection of precursors that reflect deviation of magmatic systems from metastable background activity. Ascent and emplacement of new basaltic magma at depth may precede eruptions by weeks to months. Transient localized carbon dioxide (CO2) emissions stemming from exsolution from depressurized magma are expected, and have been observed weeks to months ahead of magmatic surface activity. Detecting such CO2 precursors by continuous ground-based monitoring operations is unfortunately not a widely implemented method yet, save a handful of volcanoes. Detecting CO2 emissions from space offers obvious advantages - however it is technologically challenging, not the least due to the increasing atmospheric burden of CO2, against which a surface emission signal is hard to discern. In a multi-year project, we have investigated the feasibility of space-borne detection of pre-eruptive volcanic CO2 passive degassing signals using observations from the Greenhouse Gas Observing SATellite (GOSAT). Since 2010, we have observed over 40 active volcanoes from space using GOSAT's special target mode. Over 72% of targets experienced at least one eruption over that time period, demonstrating the potential utility of space-borne CO2 observations in non-imaging target-mode (point source monitoring mode). While many eruption precursors don't produce large enough CO2 signals to exceed space-borne detection thresholds of current satellite sensors, some of our observations have nevertheless already shown significant positive anomalies preceding eruptions at basaltic volcanoes. In 2014, NASA launched its first satellite dedicated to atmospheric CO2 observation, the Orbiting Carbon Observatory (OCO-2). Its observation strategy differs from the single-shot GOSAT instrument. At the expense of GOSAT's fast time series capability (3-day repeat cycle, vs. 16 for OCO-2), its 8-footprint continuous swath can slice

  14. Advanced CO2 Removal Technology Development

    NASA Technical Reports Server (NTRS)

    Finn, John E.; Verma, Sunita; Forrest, Kindall; LeVan, M. Douglas

    2001-01-01

    The Advanced CO2 Removal Technical Task Agreement covers three active areas of research and development. These include a study of the economic viability of a hybrid membrane/adsorption CO2 removal system, sorbent materials development, and construction of a database of adsorption properties of important fixed gases on several adsorbent material that may be used in CO2 removal systems. The membrane/adsorption CO2 removal system was proposed as a possible way to reduce the energy consumption of the four-bed molecular sieve system now in use. Much of the energy used by the 4BMS is used to desorb water removed in the device s desiccant beds. These beds might be replaced by a desiccating membrane that moves the water from [he incoming stream directly into the outlet stream. The approach may allow the CO2 removal beds to operate at a lower temperature. A comparison between models of the 4BMS and hybrid systems is underway at Vanderbilt University. NASA Ames Research Center has been investigating a Ag-exchanged zeolites as a possible improvement over currently used Ca and Na zeolites for CO2 removal. Silver ions will complex with n:-bonds in hydrocarbons such as ethylene, giving remarkably improved selectivity for adsorption of those materials. Bonds with n: character are also present in carbon oxides. NASA Ames is also continuing to build a database for adsorption isotherms of CO2, N2, O2, CH4, and Ar on a variety of sorbents. This information is useful for analysis of existing hardware and design of new processes.

  15. NaSrCo2F7, a Co(2+) pyrochlore antiferromagnet.

    PubMed

    Krizan, J W; Cava, R J

    2015-07-29

    We report the crystal growth, by the Bridgeman-Stockbarger method, and the basic magnetic properties of a new cobalt-based pyrochlore, NaSrCo2F7. Single-crystal structure determination shows that Na and Sr are completely disordered on the non-magnetic large atom A sites, while magnetic [Formula: see text] Co(2+) fully occupies the pyrochlore lattice B sites. NaSrCo2F7 displays strong antiferromagnetic interactions ([Formula: see text]), a large effective moment ([Formula: see text]), and no spin freezing until 3 K. Thus, NaSrCo2F7 is a geometrically frustrated antiferromagnet with a frustration index [Formula: see text]. Ac susceptibility, dc susceptibility, and heat capacity are utilized to characterize the spin freezing. We argue that NaSrCo2F7 and the related material NaCaCo2F7 are examples of frustrated pyrochlore antiferromagnets with weak bond disorder. PMID:26154596

  16. CO2 and CO Simulations and Their Source Signature Indicated by CO/CO2

    NASA Technical Reports Server (NTRS)

    Kawa, Randy; Huisheng, Bian

    2004-01-01

    Three years (2000-2002) atmospheric CO2 and CO fields are simulated by a Chemistry Transport Model driven by the assimilated meteorological fields from GEOS-4. The simulated CO2 and CO are evaluated by measurements from surface (CMDL), satellite (MOPITT/CO), and aircraft. The model-observation comparisons indicate reasonable agreement in both source and remote regions, and in the lower and upper troposphere. The simulation also captures the seasonality of CO2 and CO variations. The ratios of CO/CO2 are analyzed over different representative regions to identify the source signature, since the anthropogenic CO comes fiom the same combustion processes as CO2. This work enables us to improve satellite inversion estimates of CO2 sources and sinks by simultaneously using satellite CO measurement.

  17. Monitoring of near surface CO2

    NASA Astrophysics Data System (ADS)

    Faber, E.; Möller, I.; Teschner, M.; Poggenburg, J.; Spickenbom, K.; Schulz, H. J.

    2009-04-01

    Monitoring of near surface CO2 ECKHARD FABER1, INGO MÖLLER1, MANFRED TESCHNER1, JÜRGEN POGGENBURG1, KAI SPICKENBOM1, HANS-MARTIN SCHULZ1,2 1Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Stilleweg 2, D-30655 Hannover, e.faber@bgr.de 2present adress: GeoForschungsZentrum Potsdam (GFZ), Telegrafenberg, D-14473 Potsdam Underground gas storage and sequestration of carbon dioxide is one of the methods to reduce the input of antropogenic CO2 into the atmosphere and its greenhouse effect. Storage of CO2 is planned in depleted reservoirs, in aquifers and in salt caverns. Storage sites must have very small leakage rates to safely store the CO2 for centuries. Thus, a careful investigation and site selection is crucial. However, any leakage of CO2 to the surface is potentially dangerous for humans and environment. Therefore, instruments and systems for the detection of any CO2 escaping the storage sites and reaching the atmosphere have to be developed. Systems to monitor gases in deep wells, groundwater and surface sediments for leaking CO2 are developed, tested and are contnuously improved. Our group is mainly analysing CO2 in shallow (down to 3 m) soil samples using automatically operating monitoring systems. The systems are equipped with sensors to measure CO2 (and other gases) concentrations and other environmental parameters (atmospheric pressure, ambient and soil temperatures, etc.). Data are measured in short intervals (minute to subminute), are stored locally and are transferred by telemetrical systems into the BGR laboratory (Weinlich et al., 2006). In addition to soil gases monitoring systems technical equipment is available for continuous underwater gas flow measurements. Several of those monitoring systems are installed in different areas like Czech Republic, Austria, Italy and Germany. To detect any leaking gas from a sequestration site after CO2 injection, the naturally existing CO2 concentration (before injection) must be known. Thus, the natural

  18. Validation of Airborne CO2 Laser Measurements

    NASA Astrophysics Data System (ADS)

    Browell, E. V.; Dobler, J. T.; Kooi, S.; Fenn, M. A.; Choi, Y.; Vay, S. A.; Harrison, F. W.; Moore, B.; Zaccheo, T. S.

    2010-12-01

    This paper discusses the flight test validation of a unique, multi-frequency, intensity-modulated, single-beam laser absorption spectrometer (LAS) that operates near 1.57 μm for remote column CO2 measurements. This laser system is under development for a future space-based mission to determine the global distribution of regional-scale CO2 sources and sinks, which is the objective of the NASA Active Sensing of CO2 Emissions during Nights, Days, and Seasons (ASCENDS) mission. A prototype of this LAS system, called the Multi-frequency Fiber Laser Lidar (MFLL), was developed by ITT, and it has been flight tested in nine airborne campaigns since May 2005. This paper focuses on the most recent results obtained over the last two years of flight-testing where the MFLL remote CO2 column measurements were evaluated against airborne in situ CO2 profile measurements traceable to World Meteorological Organization standards. A comprehensive multiple-aircraft flight test program was conducted over Oklahoma and Virginia in July-August 2009. The MFLL obtained surface reflectance and average CO2 column variations along the 50-km flight legs over the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Central Facility (CF) in Lamont, Oklahoma; over rural Virginia and North Carolina; and over the Chesapeake Bay. For a flight altitude of 4.6 km, the average signal to noise ratio (SNR) for a 1-s CO2 column measurement was found to be 760, which is the equivalent of a CO2 mixing ratio precision of 0.60 ppmv, and for a 10-s average the SNR was found to be 2002 or 0.20 ppmv. Absolute comparisons of MFLL-derived and in situ-derived CO2 column measurements were made for all daytime flights conducted over Oklahoma and Virginia with an average agreement to within 0.32 ppmv. A major ASCENDS flight test campaign was conducted using the NASA DC-8 during 6-18 July 2010. The MFLL system and associated in situ CO2 instrumentation were operated on DC-8 flights over the Central Valley

  19. Decarboxylation, CO2 and the reversion problem.

    PubMed

    Kluger, Ronald

    2015-11-17

    Decarboxylation reactions occur rapidly in enzymes but usually are many orders of magnitude slower in solution, if the reaction occurs at all. Where the reaction produces a carbanion and CO2, we would expect that the high energy of the carbanion causes the transition state for C-C bond cleavage also to be high in energy. Since the energy of the carbanion is a thermodynamic property, an enzyme obviously cannot change that property. Yet, enzymes overcome the barrier to forming the carbanion. In thinking about decarboxylation, we had assumed that CO2 is well behaved and forms without its own barriers. However, we analyzed reactions in solution of compounds that resemble intermediates in enzymic reaction and found some of them to be subject to unexpected forms of catalysis. Those results caused us to discard the usual assumptions about CO2 and carbanions. We learned that CO2 can be a very reactive electrophile. In decarboxylation reactions, where CO2 forms in the same step as a carbanion, separation of the products might be the main problem preventing the forward reaction because the carbanion can add readily to CO2 in competition with their separation and solvation. The basicity of the carbanion also might be overestimated because when we see that the decarboxylation is slow, we assume that it is because the carbanion is high in energy. We found reactions where the carbanion is protonated internally; CO2 appears to be able to depart without reversion more rapidly. We tested these ideas using kinetic analysis of catalytic reactions, carbon kinetic isotope effects, and synthesis of predecarboxylation intermediates. In another case, we observed that the decarboxylation is subject to general base catalysis while producing a significant carbon kinetic isotope effect. This requires both a proton transfer from an intermediate and C-C bond-breaking in the rate-determining step. This would occur if the route involves the surprising initial addition of water to the carboxyl

  20. Direct Copolymerization of CO2 and Diols

    PubMed Central

    Tamura, Masazumi; Ito, Kazuki; Honda, Masayoshi; Nakagawa, Yoshinao; Sugimoto, Hiroshi; Tomishige, Keiichi

    2016-01-01

    Direct polymerization of CO2 and diols is promising as a simple and environmental-benign method in place of conventional processes using high-cost and/or hazardous reagents such as phosgene, carbon monoxide and epoxides, however, there are no reports on the direct method due to the inertness of CO2 and severe equilibrium limitation of the reaction. Herein, we firstly substantiate the direct copolymerization of CO2 and diols using CeO2 catalyst and 2-cyanopyridine promotor, providing the alternating cooligomers in high diol-based yield (up to 99%) and selectivity (up to >99%). This catalyst system is applicable to various diols including linear C4-C10 α,ω-diols to provide high yields of the corresponding cooligomers, which cannot be obtained by well-known methods such as copolymerization of CO2 and cyclic ethers and ring-opening polymerization of cyclic carbonates. This process provides us a facile synthesis method for versatile polycarbonates from various diols and CO2 owing to simplicity of diols modification. PMID:27075987

  1. Direct CO2-Methanation of flue gas

    NASA Astrophysics Data System (ADS)

    Müller, Klaus; Fleige, Michael; Rachow, Fabian; Israel, Johannes; Schmeißer, Dieter

    2013-04-01

    Already discovered by Paul Sabatier in 1902 the Hydrogenation according to CO2 + 4H2 ->CH4 + 2H2O nowadays is discussed in the course of the "Power-to-Gas" approach to utilize excess energy from renewable electricity generation in times of oversupply of electricity. We investigate the behavior of this process in a simulated flue gas atmosphere of conventional base load power plants, which could be used as constant sources of the reactant CO2. In relation to an approach related to carbon capture and cycling, the conversion of CO2 directly from the flue gas of a conventional power plant is a new aspect and has several advantages: The conversion of CO2 into methane could be integrated directly into the combustion process. Even older power plants could be upgraded and used as a possible source for CO2, in the same sense as the amine cleaning of flue gas, as a post combustion process. Further, waste heat of the power plant could be used as process energy for the catalytic reaction. Therefore the influence of different flue gas compositions such as varying contents of nitrogen and residual oxygen are tested in a laboratory scale. The heterogeneous catalysis process is investigated with regard to conversion rates, yield and selectivity and long-term stability of the Ni-catalyst. Also the influence of typical contaminations like SO2 is investigated and will be presented.

  2. The supply chain of CO2 emissions

    PubMed Central

    Davis, Steven J.; Peters, Glen P.; Caldeira, Ken

    2011-01-01

    CO2 emissions from the burning of fossil fuels are conventionally attributed to the country where the emissions are produced (i.e., where the fuels are burned). However, these production-based accounts represent a single point in the value chain of fossil fuels, which may have been extracted elsewhere and may be used to provide goods or services to consumers elsewhere. We present a consistent set of carbon inventories that spans the full supply chain of global CO2 emissions, finding that 10.2 billion tons CO2 or 37% of global emissions are from fossil fuels traded internationally and an additional 6.4 billion tons CO2 or 23% of global emissions are embodied in traded goods. Our results reveal vulnerabilities and benefits related to current patterns of energy use that are relevant to climate and energy policy. In particular, if a consistent and unavoidable price were imposed on CO2 emissions somewhere along the supply chain, then all of the parties along the supply chain would seek to impose that price to generate revenue from taxes collected or permits sold. The geographical concentration of carbon-based fuels and relatively small number of parties involved in extracting and refining those fuels suggest that regulation at the wellhead, mine mouth, or refinery might minimize transaction costs as well as opportunities for leakage. PMID:22006314

  3. Direct Copolymerization of CO2 and Diols

    NASA Astrophysics Data System (ADS)

    Tamura, Masazumi; Ito, Kazuki; Honda, Masayoshi; Nakagawa, Yoshinao; Sugimoto, Hiroshi; Tomishige, Keiichi

    2016-04-01

    Direct polymerization of CO2 and diols is promising as a simple and environmental-benign method in place of conventional processes using high-cost and/or hazardous reagents such as phosgene, carbon monoxide and epoxides, however, there are no reports on the direct method due to the inertness of CO2 and severe equilibrium limitation of the reaction. Herein, we firstly substantiate the direct copolymerization of CO2 and diols using CeO2 catalyst and 2-cyanopyridine promotor, providing the alternating cooligomers in high diol-based yield (up to 99%) and selectivity (up to >99%). This catalyst system is applicable to various diols including linear C4-C10 α,ω-diols to provide high yields of the corresponding cooligomers, which cannot be obtained by well-known methods such as copolymerization of CO2 and cyclic ethers and ring-opening polymerization of cyclic carbonates. This process provides us a facile synthesis method for versatile polycarbonates from various diols and CO2 owing to simplicity of diols modification.

  4. CO2 DIAL measurements of water vapor

    NASA Technical Reports Server (NTRS)

    Grant, William B.; Margolis, Jack S.; Brothers, Alan M.; Tratt, David M.

    1987-01-01

    CO2 lidars have heretofore been used to measure water vapor concentrations primarily using the 10R(20) line at 10.247 microns, which has a strong overlap with a water vapor absorption line. This paper discusses the use of that line as well as other CO2 laser lines for which the absorption coefficients are weaker. The literature on measurement of water vapor absorption coefficients using CO2 lasers is reviewed, and the results from four laboratories are shown to be generally consistent with each other after they are normalized to the same partial pressure, temperature, and ethylene absorption coefficent for the 10P(14) CO2 laser line; however, the agreement with the Air Force Geophysics Laboratory's HITRAN and FASCOD 2 spectral data tapes is not good either for the water vapor absorption lines or for the water vapor continuum. Demonstration measurements of atmospheric water vapor have been conducted using the Mobile Atmospheric Pollutant Mapping System, a dual CO2 lidar system using heterodyne detection. Results are discussed for measurements using three sets of laser line pairs covering a wide range of water vapor partial pressures.

  5. Direct Copolymerization of CO2 and Diols.

    PubMed

    Tamura, Masazumi; Ito, Kazuki; Honda, Masayoshi; Nakagawa, Yoshinao; Sugimoto, Hiroshi; Tomishige, Keiichi

    2016-01-01

    Direct polymerization of CO2 and diols is promising as a simple and environmental-benign method in place of conventional processes using high-cost and/or hazardous reagents such as phosgene, carbon monoxide and epoxides, however, there are no reports on the direct method due to the inertness of CO2 and severe equilibrium limitation of the reaction. Herein, we firstly substantiate the direct copolymerization of CO2 and diols using CeO2 catalyst and 2-cyanopyridine promotor, providing the alternating cooligomers in high diol-based yield (up to 99%) and selectivity (up to >99%). This catalyst system is applicable to various diols including linear C4-C10 α,ω-diols to provide high yields of the corresponding cooligomers, which cannot be obtained by well-known methods such as copolymerization of CO2 and cyclic ethers and ring-opening polymerization of cyclic carbonates. This process provides us a facile synthesis method for versatile polycarbonates from various diols and CO2 owing to simplicity of diols modification. PMID:27075987

  6. CO2-Binding-Organic-Liquids-Enhanced CO2 Capture using Polarity-Swing-Assisted Regeneration

    SciTech Connect

    Zhang, Jian; Kutnyakov, Igor; Koech, Phillip K.; Zwoster, Andy; Howard, Chris; Zheng, Feng; Freeman, Charles J.; Heldebrant, David J.

    2013-01-01

    A new solvent-based CO2 capture process couples the unique attributes of non-aqueous, CO2-binding organic liquids (CO2BOLs) with the newly discovered polarity-swing-assisted regeneration (PSAR) process that is unique to switchable ionic liquids. Laboratory measurements with PSAR indicate the ability to achieve a regeneration effect at 75°C comparable to that at 120°C using thermal regeneration only. Initial measurements also indicate that the kinetic behavior of CO2 release is also improved with PSAR. Abstract cleared PNWD-SA-9743

  7. Light-duty vehicle CO2 targets consistent with 450 ppm CO2 stabilization.

    PubMed

    Winkler, Sandra L; Wallington, Timothy J; Maas, Heiko; Hass, Heinz

    2014-06-01

    We present a global analysis of CO2 emission reductions from the light-duty vehicle (LDV) fleet consistent with stabilization of atmospheric CO2 concentration at 450 ppm. The CO2 emission reductions are described by g CO2/km emission targets for average new light-duty vehicles on a tank-to-wheel basis between 2010 and 2050 that we call CO2 glide paths. The analysis accounts for growth of the vehicle fleet, changing patterns in driving distance, regional availability of biofuels, and the changing composition of fossil fuels. New light-duty vehicle fuel economy and CO2 regulations in the U.S. through 2025 and in the EU through 2020 are broadly consistent with the CO2 glide paths. The glide path is at the upper end of the discussed 2025 EU range of 68-78 g CO2/km. The proposed China regulation for 2020 is more stringent than the glide path, while the 2017 Brazil regulation is less stringent. Existing regulations through 2025 are broadly consistent with the light-duty vehicle sector contributing to stabilizing CO2 at approximately 450 ppm. The glide paths provide long-term guidance for LDV powertrain/fuel development. PMID:24798684

  8. Surface CO2 leakage during the first shallow subsurface CO2release experiment

    SciTech Connect

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

    2007-09-15

    A new field facility was used to study CO2 migrationprocesses and test techniques to detect and quantify potential CO2leakage 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-mdepth) horizontal well. The spatio-temporal evolution of leakage wasmapped through repeated grid measurements of soil CO2 flux (FCO2). Thesurface leakage onset, approach to steady state, and post-release declinematched model predictions closely. Modeling suggested that minimal CO2was taken up by groundwater through dissolution, and CO2 spread out ontop of the water table. FCO2 spatial patterns were related to well designand soil physical properties. Estimates of total CO2 discharge along withsoil respiration and leakage discharge highlight the influence ofbackground CO2 flux variations on detection of CO2 leakagesignals.

  9. Oxygen isotope fractionation in stratospheric CO2

    NASA Technical Reports Server (NTRS)

    Thiemens, M. H.; Jackson, T.; Mauersberger, K.; Schueler, B.; Morton, J.

    1991-01-01

    A new cryogenic collection system has been flown on board a balloon gondola to obtain separate samples of ozone and carbon dioxide without entrapping major atmospheric gases. Precision laboratory isotopic analysis of CO2 samples collected between 26 and 35.5 km show a mass-independent enrichment in both O-17 and O-18 of about 11 per mil above tropospheric values. Ozone enrichment in its heavy isotopes was 9 to 16 percent in O3-50 and 8 to 11 percent in O3-49, respectively (Schueler et al., 1990). A mechanism to explain the isotope enrichment in CO2 has been recently proposed by Yung et al. (1991). The model is based on the isotope exchange between CO2 and O3 via O(1D), resulting in a transfer of the ozone isotope enrichment to carbon dioxide. Predicted enrichment and measured values agree well.

  10. CW CO2 Laser Induced Chemical Reactions

    NASA Astrophysics Data System (ADS)

    Pola, Joseph

    1989-05-01

    CW CO2 laser driven reactions between sulfur hexafluoride and carbon oxide, carbon suboxide, carbonyl sulfide and carbon disulfide proceed at subatmospheric pressures and yield fluorinated carbon compounds and sulfur tetrafluoride. CW CO2 laser driven reactions of organic compounds in the presence of energy-conveying sulfur hexafluoride show reaction course different from that normally observed due to elimination of reactor hot surface effects. The examples concern the decomposition of polychlorohydrocarbons, 2-nitropropane, tert.-butylamine, allyl chloride, spirohexane, isobornyl acetate and the oxidation of haloolefins. CW CO2 laser induced fragmentation of 1-methyl-l-silacyclobutanes and 4-silaspiro(3.4)octane in the presence of sulfur hexafluoride is an effective way for preparation and deposition of stable organosilicon polymers.

  11. The oceanic sink for anthropogenic CO2.

    PubMed

    Sabine, Christopher L; Feely, Richard A; Gruber, Nicolas; Key, Robert M; Lee, Kitack; Bullister, John L; Wanninkhof, Rik; Wong, C S; Wallace, Douglas W R; Tilbrook, Bronte; Millero, Frank J; Peng, Tsung-Hung; Kozyr, Alexander; Ono, Tsueno; Rios, Aida F

    2004-07-16

    Using inorganic carbon measurements from an international survey effort in the 1990s and a tracer-based separation technique, we estimate a global oceanic anthropogenic carbon dioxide (CO2) sink for the period from 1800 to 1994 of 118 +/- 19 petagrams of carbon. The oceanic sink accounts for approximately 48% of the total fossil-fuel and cement-manufacturing emissions, implying that the terrestrial biosphere was a net source of CO2 to the atmosphere of about 39 +/- 28 petagrams of carbon for this period. The current fraction of total anthropogenic CO2 emissions stored in the ocean appears to be about one-third of the long-term potential. PMID:15256665

  12. Sequestration of CO2 by concrete carbonation.

    PubMed

    Galan, Isabel; Andrade, Carmen; Mora, Pedro; Sanjuan, Miguel A

    2010-04-15

    Carbonation of reinforced concrete is one of the causes of corrosion, but it is also a way to sequester CO2. The characteristics of the concrete cover should ensure alkaline protection for the steel bars but should also be able to combine CO2 to a certain depth. This work attempts to advance the knowledge of the carbon footprint of cement. As it is one of the most commonly used materials worldwide, it is very important to assess its impact on the environment. In order to quantify the capacity of cement based materials to combine CO2 by means of the reaction with hydrated phases to produce calcium carbonate, Thermogravimetry and the phenolphthalein indicator have been used to characterize several cement pastes and concretes exposed to different environments. The combined effect of the main variables involved in this process is discussed. The moisture content of the concrete seems to be the most influential parameter. PMID:20225850

  13. CO2 mitigation via accelerated limestone weathering

    USGS Publications Warehouse

    Rau, G.H.; Knauss, K.G.; Langer, W.H.; Caldeira, K.

    2004-01-01

    Accelerated weathering of limestone (AWL: CO22+ + CaCO3 + H2O ??? Ca2+ + 2HCO3- as a low-tech, inexpensive, high-capacity, environmentally-friendly CO2 capture and sequestration technology was evaluated. With access to seawater and limestone being essential to this approach, significant limestone resources were close to most CO2-emitting power plants along the coastal US. Waste fines, representing > 20% of current US crushed limestone production (> 109 tons/yr), could be used as an inexpensive source of AWL carbonate. AWL end-solution disposal in the ocean would significantly reduce effects on ocean pH and carbonate chemistry relative to those caused by direct atmospheric or ocean CO2 disposal. Indeed, the increase in ocean Ca2+ and bicarbonate offered by AWL should enhance growth of corals and other calcifying marine organisms.

  14. CO2 sequestration in basalts: laboratory measurements

    NASA Astrophysics Data System (ADS)

    Otheim, L. T.; Adam, L.; van Wijk, K.; McLing, T. L.; Podgorney, R. K.

    2010-12-01

    Geologic sequestration of CO2 is proposed as the only promising large-scale method to help reduce CO2 gas emission by its capture at large point sources and subsequent long-term storage in deep geologic formations. Reliable and cost-effective monitoring will be important aspect of ensuring geological sequestration is a safe, effective, and acceptable method for CO2 emissions mitigation. Once CO2 injection starts, seismic methods can be used to monitor the migration of the carbon dioxide plume. To calibrate changes in rock properties from field observations, we propose to first analyze changes in elastic properties on basalt cores. Carbon dioxide sequestration in basalt rocks results in fluid substitution and mixing of CO2 with water and rock mineralizations. Carbon dioxide sequestration in mafic rocks creates reactions such as Mg2SiO 4 + CaMgSi2O 6 + 4CO2 = Mg 3Ca(CO 3) 4 + 3SiO2 whereby primary silicate minerals within the basalt react with carbonic acid laden water to creating secondary carbonate minerals and silicates. Using time-lapse laboratory scale experiments, such as laser generated ultrasonic wave propagation; it is possible to observe small changes in the physical properties of a rock. We will show velocity and modulus measurements on three basalt core samples for different saturation. The ultimate goal of the project is to track seismic changes due to fluid substitution and mineralization. The porosity of our basalts ranges from 8% to 12%, and the P-wave velocity increases by 20% to 40% from dry to water saturated conditions. Petrographic analysis (CT-scans, thin sections, XRF, XRf) will aid in the characterization of the mineral structure in these basalts and its correlation to seismic properties changes resulting from fluid substitution and mineralization.

  15. CO2 Orbital Trends in Comets

    NASA Astrophysics Data System (ADS)

    Kelley, Michael; Bodewits, Dennis; Feaga, Lori; Knight, Matthew; McKay, Adam; Snodgrass, Colin; Wooden, Diane

    2016-08-01

    Carbon dioxide is a primary volatile in comet nuclei, and potentially a major contributor to comet activity (i.e., the process of mass loss). However, CO2 cannot be observed directly from the ground, and past surveys of this molecule in comets were limited to space-borne snapshot observations. This situation limits our understanding of the behavior of CO2 in comets, and its role in driving comet mass loss. To address this deficiency, we were awarded a Cy11 Spitzer program designed to quantify the production rate of CO2 on >month-long timescales for 21 comets. We request an additional 269~hr in Cy13 to complete the Spitzer portion of our survey, and to add three more comets (46P/Wirtanen and 2 Target of Opportunity Oort cloud comets). Our survey is designed to probe the orbital trends of CO2 production in the comet population. We aim to: 1) examine the role of CO2 in the persistent post-perihelion activity observed in Jupiter-family comets; 2) measure the seasonal variations of CO2/H2O as a proxy for nucleus heterogeneity, when possible; 3) search for orbital trends sensitive to cumulative insolation as a proxy for nucleus layering; and 4) examine how Oort cloud comets evolve by comparing dynamically new and old targets. The final data set will allow us to investigate the effects of heating on the evolution of comets, if nucleus structures can be inferred through activity, and set the stage for JWST investigations into comet activity and composition.

  16. 10 MW Supercritical CO2 Turbine Test

    SciTech Connect

    Turchi, Craig

    2014-01-29

    The Supercritical CO2 Turbine Test project was to demonstrate the inherent efficiencies of a supercritical carbon dioxide (s-CO2) power turbine and associated turbomachinery under conditions and at a scale relevant to commercial concentrating solar power (CSP) projects, thereby accelerating the commercial deployment of this new power generation technology. The project involved eight partnering organizations: NREL, Sandia National Laboratories, Echogen Power Systems, Abengoa Solar, University of Wisconsin at Madison, Electric Power Research Institute, Barber-Nichols, and the CSP Program of the U.S. Department of Energy. The multi-year project planned to design, fabricate, and validate an s-CO2 power turbine of nominally 10 MWe that is capable of operation at up to 700°C and operates in a dry-cooled test loop. The project plan consisted of three phases: (1) system design and modeling, (2) fabrication, and (3) testing. The major accomplishments of Phase 1 included: Design of a multistage, axial-flow, s-CO2 power turbine; Design modifications to an existing turbocompressor to provide s-CO2 flow for the test system; Updated equipment and installation costs for the turbomachinery and associated support infrastructure; Development of simulation tools for the test loop itself and for more efficient cycle designs that are of greater commercial interest; Simulation of s-CO2 power cycle integration into molten-nitrate-salt CSP systems indicating a cost benefit of up to 8% in levelized cost of energy; Identification of recuperator cost as a key economic parameter; Corrosion data for multiple alloys at temperatures up to 650ºC in high-pressure CO2 and recommendations for materials-of-construction; and Revised test plan and preliminary operating conditions based on the ongoing tests of related equipment. Phase 1 established that the cost of the facility needed to test the power turbine at its full power and temperature would exceed the planned funding for Phases 2 and 3. Late

  17. Selective Oxytrifluoromethylation of Allylamines with CO2.

    PubMed

    Ye, Jian-Heng; Song, Lei; Zhou, Wen-Jun; Ju, Tao; Yin, Zhu-Bao; Yan, Si-Shun; Zhang, Zhen; Li, Jing; Yu, Da-Gang

    2016-08-16

    Reported is the first oxy-trifluoromethylation of allylamines with carbon dioxide (CO2 ) using copper catalysis, thus leading to important CF3 -containing 2-oxazolidones. It is also the first time CO2 , a nontoxic and easily available greenhouse gas, has been used to tune the difunctionalization of alkenes from amino- to oxy-trifluoromethylation. Of particular note, this multicomponent reaction is highly chemo-, regio-, and diastereoselective under redox-neutral and mild reaction conditions. Moreover, these reactions feature good functional-group tolerance, broad substrate scope, easy scalability and facile product diversification. The important products could also be formed with either spirocycles or two adjacent tetrasubstituted carbon centers. PMID:27411560

  18. Leak Path Development in CO2 Wells

    NASA Astrophysics Data System (ADS)

    Torsater, M.; Todorovic, J.; Opedal, N.; Lavrov, A.

    2014-12-01

    Wells have in numerous scientific works been denoted the "weak link" of safe and cost-efficient CO2 Capture and Storage (CCS). Whether they are active or abandoned, all wells are man-made intrusions into the storage reservoir with sealing abilities depending on degradable materials like steel and cement. If dense CO2 is allowed to expand (e.g. due to leakage) it will cool down its surroundings and cause strong thermal and mechanical loading on the wellbore. In addition, CO2 reacts chemically with rock, cement and steel. To ensure long-term underground containment, it is therefore necessary to study how, why, where and when leakage occurs along CO2wells. If cement bonding to rock or casing is poor, leak paths can form already during drilling and completion of the well. In the present work, we have mapped the bonding quality of cement-rock and cement-steel interfaces - and measured their resistance towards CO2 flow. This involved a large experimental matrix including different rocks, steels, cement types and well fluids. The bonding qualities were measured on composite cores using micro computed tomography (µ-CT), and CO2 was flooded through the samples to determine leakage rates. These were further compared to numerical simulations of leakage through the digitalized µ-CT core data, and CO2chemical interactions with the materials were mapped using electron microscopy. We also present a new laboratory set-up for measuring how well integrity is affected by downhole temperature variations - and we showcase some initial results. Our work concludes that leak path development in CO2 wells depends critically on the drilling fluids and presflushes/spacers chosen already during drilling and completion of a well. Fluid films residing on rock and casing surfaces strongly degrade the quality of cement bonding. The operation of the well is also important, as even slight thermal cycling (between 10°C and 95°C on casing) leads to significant de-bonding of the annular cement.

  19. CO2 laser cutting of natural granite

    NASA Astrophysics Data System (ADS)

    Riveiro, A.; Mejías, A.; Soto, R.; Quintero, F.; del Val, J.; Boutinguiza, M.; Lusquiños, F.; Pardo, J.; Pou, J.

    2016-01-01

    Commercial black granite boards (trade name: "Zimbabwe black granite") 10 mm thick, were successfully cut by a 3.5 kW CO2 laser source. Cutting quality, in terms of kerf width and roughness of the cut wall, was assessed by means of statistically planned experiments. No chemical modification of the material in the cutting walls was detected by the laser beam action. Costs associated to the process were calculated, and the main factors affecting them were identified. Results reported here demonstrate that cutting granite boards could be a new application of CO2 laser cutting machines provided a supersonic nozzle is used.

  20. CO2 chemosensing in rat oesophagus

    PubMed Central

    Akiba, Y; Mizumori, M; Kuo, M; Ham, M; Guth, P H; Engel, E; Kaunitz, J D

    2016-01-01

    Background Acid in the oesophageal lumen is often sensed as heartburn. It was hypothesised that luminal CO2, a permeant gas, rather than H+, permeates through the epithelium, and is converted to H+, producing an afferent neural signal by activating chemosensors. Methods The rat lower oesophageal mucosa was superfused with pH 7.0 buffer, and pH 1.0 or pH 6.4 high CO2 (PCO2 = 260 Torr) solutions with or without the cell-permeant carbonic anhydrase (CA) inhibitor methazolamide (MTZ, 1 mM), the cell-impermeant CA inhibitor benzolamide (BNZ, 0.1 mM), the transient receptor potential vanilloid 1 (TRPV1) antagonist capsazepine (CPZ, 0.5 mM) or the acid-sensing ion channel (ASIC) inhibitor amiloride (0.1 mM). Interstitial pH (pHint) was measured with 5′,6′-carboxyfluorescein (5 mg/kg intravenously) loaded into the interstitial space, and blood flow was measured with laser-Doppler. Results Perfusion of a high CO2 solution induced hyperaemia without changing pHint, mimicking the effect of pH 1.0 perfusion. Perfused MTZ, BNZ, CPZ and amiloride all inhibited CO2-induced hyperaemia. CA XIV was expressed in the prickle cells, with CA XII in the basal cells. TRPV1 was expressed in the stratum granulosum and in the muscularis mucosa, whereas all ASICs were expressed in the prickle cells, with ASIC3 additionally in the muscularis mucosa. Conclusions The response to CO2 perfusion suggests that CO2 diffuses through the stratum epithelium, interacting with TRPV1 and ASICs in the epithelium or in the submucosa. Inhibition of the hyperaemic response to luminal CO2 by CA, TRPV1 and ASIC inhibitors implicates CA and these chemosensors in transduction of the luminal acid signal. Transepithelial CO2 permeation may explain how luminal H+ equivalents can rapidly be transduced into hyperaemia, and the sensation of heartburn. PMID:18682519

  1. CO2 Acquisition Membrane (CAM) Project

    NASA Technical Reports Server (NTRS)

    Mason, L. W.; Way, J. D.; Vlasse, M.

    2001-01-01

    The CO2 Acquisition Membrane (CAM) project will develop, test, and analyze membrane materials for separation and purification of carbon dioxide (CO2) from mixtures of gases, such as those found in the Martian atmosphere. The CAM technology will enable passive separation of these gases, allow energy efficient acquisition and purification of these important resources, and lay the foundation for future unmanned sample return and human space missions. The CAM membranes are targeted toward In Situ Resource Utilization (ISRU) applications, such as In Situ Propellant Production (ISPP) and In Situ Consumables Production (ISCP).

  2. Crystallization of CO2 ice and the absence of amorphous CO2 ice in space

    PubMed Central

    Escribano, Rafael M.; Muñoz Caro, Guillermo M.; Cruz-Diaz, Gustavo A.; Rodríguez-Lazcano, Yamilet; Maté, Belén

    2013-01-01

    Carbon dioxide (CO2) is one of the most relevant and abundant species in astrophysical and atmospheric media. In particular, CO2 ice is present in several solar system bodies, as well as in interstellar and circumstellar ice mantles. The amount of CO2 in ice mantles and the presence of pure CO2 ice are significant indicators of the temperature history of dust in protostars. It is therefore important to know if CO2 is mixed with other molecules in the ice matrix or segregated and whether it is present in an amorphous or crystalline form. We apply a multidisciplinary approach involving IR spectroscopy in the laboratory, theoretical modeling of solid structures, and comparison with astronomical observations. We generate an unprecedented highly amorphous CO2 ice and study its crystallization both by thermal annealing and by slow accumulation of monolayers from the gas phase under an ultrahigh vacuum. Structural changes are followed by IR spectroscopy. We also devise theoretical models to reproduce different CO2 ice structures. We detect a preferential in-plane orientation of some vibrational modes of crystalline CO2. We identify the IR features of amorphous CO2 ice, and, in particular, we provide a theoretical explanation for a band at 2,328 cm−1 that dominates the spectrum of the amorphous phase and disappears when the crystallization is complete. Our results allow us to rule out the presence of pure and amorphous CO2 ice in space based on the observations available so far, supporting our current view of the evolution of CO2 ice. PMID:23858474

  3. Greenland CO2 and δ13C of CO2 - assigning the contamination

    NASA Astrophysics Data System (ADS)

    Jenk, T.; Rubino, M.; Etheridge, D.; Bigler, M.; Blunier, T.

    2012-04-01

    Analysis of air extracted from bubbles of Greenland ice results in considerably higher CO2 concentrations compared to records from Antarctic sites. This can not be explained by the inter-hemispheric gradient expected for past climatic conditions. Instead, it is attributed to chemical reactions between impurities in the ice, contributing excess CO2 to the atmospheric signal which was initially trapped in the bubbles. This is consistent with the fact that Greenland ice contains a significantly higher amount of impurities compared to Antarctic ice. Different candidates of CO2 producing chemical reactions were suggested by previous studies: (i) the acidification of carbonates, (ii) the oxidation of hydrocarbons and (iii) the photodecarboxilation of humic like substances. However, there is no agreement on how much each of the above reactions contributes. This study aims to identify the contribution from organic and inorganic sources to the Greenland CO2 excess. Compared to previous studies we base our analysis on an increased set of parameters and data points. We discuss data of CO2 and δ13C-CO2, both in high (2.5 cm) and low resolution (55 to 110 cm) along with parallel records of chemical impurities from three different sites in Greenland. The samples for the presented high resolution CO2 and δ13C of CO2 records were measured on a new set-up at the Centre for Ice and Climate (needle cracker, GC-IRMS).

  4. CO2 Virtual Science Data Environment: Providing Streamlined Access to CO2 Data

    NASA Astrophysics Data System (ADS)

    Nguyen, H.; Cinquini, L.; Davidoff, S.; Duran, B.; Eldering, A.; Granat, R. A.; Gunson, M. R.; Hofman, J.; Knosp, B.; Murphy, E.; Osterman, G. B.; Zimdars, P.

    2014-12-01

    CO2 is an important greenhouse gas and therefore characterizing and understanding its global distribution is crucial for the study of Earth's changing climate. Currently, satellite remote sensing measurements of CO2 are available from the Greenhouse gases Observing SATellite (GOSAT), Atmospheric InfraRed Sounder (AIRS), Orbiting Carbon Observatory 2 (OCO-2), and Tropospheric Emission Spectrometer (TES). Traditionally, data from these different missions are distributed separately from one another and they each possess different data formats, making it cumbersome for researchers to access, analyze, and perform inter-comparison. We present an effort at JPL to design a web-based science data environment (co2.jpl.nasa.gov) that allows users to access and utilize CO2 data from GOSAT, AIRS, OCO-2, TES, and the ground-based Total Carbon Column Observing Network (TCCON) in a single user-friendly interface. The features of the data environment include the ability to download full mission-specific CO2-related Level 2 data files or to customize them based on location, time, data variable, version, and format. An important feature of the JPL CO2 data environment is that it allows generation of customized Level 3 products and provides detailed documentation on the mission specifications along with technical data information. These tools are designed to allow users streamlined access to relevant remote sensing and ground-based CO2 datasets in order to facilitate research on atmospheric CO2.

  5. TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2N)

    Atmospheric Science Data Center

    2015-01-30

    TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2N) News:  TES News ... L2 Platform:  TES/Aura L2 Carbon Dioxide Spatial Coverage:  5.2 x 8.5 km nadir ... Subset Data: TES Order Tool Parameters:  Carbon Dioxide Order Data:  Reverb:   Order Data ...

  6. TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2NS)

    Atmospheric Science Data Center

    2015-01-30

    TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2NS) News:  TES News ... L2 Platform:  TES/Aura L2 Carbon Dioxide Spatial Coverage:  5.3 x 8.5 km nadir ... Subset Data: TES Order Tool Parameters:  Carbon Dioxide Order Data:  Reverb:   Order Data ...

  7. CO2 adsorption isotherm on clay minerals and the CO2 accessibility into the clay interlayer

    NASA Astrophysics Data System (ADS)

    Gensterblum, Yves; Bertier, Pieter; Busch, Andreas; Rother, Gernot; Krooß, Bernhard

    2013-04-01

    Large-scale CO2 storage in porous rock formations at 1-3 km depth is seen as a global warming mitigation strategy. In this process, CO2 is separated from the flue gas of coal or gas power plants, compressed, and pumped into porous subsurface reservoirs with overlying caprocks (seals). Good seals are mechanically and chemically stable caprocks with low porosity and permeability. They prevent leakage of buoyant CO2 from the reservoir. Caprocks are generally comprised of thick layers of shale, and thus mainly consist of clay minerals. These clays can be affected by CO2-induced processes, such as swelling or dissolution. The interactions of CO2 with clay minerals in shales are at present poorly understood. Sorption measurements in combination scattering techniques could provide fundamental insight into the mechanisms governing CO2-clay interaction. Volumetric sorption techniques have assessed the sorption of supercritical CO2 onto coal (Gensterblum et al., 2010; Gensterblum et al., 2009), porous silica (Rother et al., 2012a) and clays as a means of exploring the potential of large-scale storage of anthropogenic CO2 in geological reservoirs (Busch et al., 2008). On different clay minerals and shales, positive values of excess sorption were measured at gas pressures up to 6 MPa, where the interfacial fluid is assumed to be denser than the bulk fluid. However, zero and negative values were obtained at higher densities, which suggests the adsorbed fluid becomes equal to and eventually less dense than the corresponding bulk fluid, or that the clay minerals expand on CO2 charging. Using a combination of neutron diffraction and excess sorption measurements, we recently deduced the interlayer density of scCO2 in Na-montmorillonite clay in its single-layer hydration state (Rother et al., 2012b), and confirmed its low density, as well as the expansion of the basal spacings. We performed neutron diffraction experiments at the FRMII diffractometer on smectite, kaolinite and illite

  8. Effects of dissolved CO2 on Shallow Freshwater Microbial Communities simulating a CO2 Leakage Scenario

    NASA Astrophysics Data System (ADS)

    Gulliver, D. M.; Lowry, G. V.; Gregory, K.

    2013-12-01

    Geological carbon sequestration is likely to be part of a comprehensive strategy to minimize the atmospheric release of greenhouse gasses, establishing a concern of sequestered CO2 leakage into overlying potable aquifers. Leaking CO2 may affect existing biogeochemical processes and therefore water quality. There is a critical need to understand the evolution of CO2 exposed microbial communities that influence the biogeochemistry in these freshwater aquifers. The evolution of microbial ecology for different CO2 exposure concentrations was investigated using fluid-slurry samples obtained from a shallow freshwater aquifer (55 m depth, 0.5 MPa, 22 °C, Escatawpa, MS). The microbial community of well samples upstream and downstream of CO2 injection was characterized. In addition, batch vessel experiments were conducted with the upstream aquifer samples exposed to varying pCO2 from 0% to 100% under reservoir temperature and pressure for up to 56 days. The microbial community of the in situ experiment and the batch reactor experiment were analyzed with 16S rRNA clone libraries and qPCR. In both the in situ experiment and the batch reactor experiment, DNA concentration did not correlate with CO2 exposure. Both the in situ experiment and the batch reactors displayed a changing microbial community with increased CO2 exposure. The well water isolate, Curvibacter, appeared to be the most tolerant genus to high CO2 concentrations in the in situ experiments and to mid-CO2 concentrations in the batch reactors. In batch reactors with pCO2 concentrations higher than experienced in situ (pCO2 = 0.5 MPa), Pseudomonas appeared to be the most tolerant genus. Findings provide insight into a dynamic biogeochemical system that will alter with CO2 exposure. Adapted microbial populations will eventually give rise to the community that will impact the metal mobility and water quality. Knowledge of the surviving microbial populations will enable improved models for predicting the fate of CO2

  9. Development of Novel CO2 Adsorbents for Capture of CO2 from Flue Gas

    SciTech Connect

    Fauth, D.J.; Filburn, T.P.; Gray, M.L.; Hedges, S.W.; Hoffman, J.; Pennline, H.W.; Filburn, T.

    2007-06-01

    Capturing CO2 emissions generated from fossil fuel-based power plants has received widespread attention and is considered a vital course of action for CO2 emission abatement. Efforts are underway at the Department of Energy’s National Energy Technology Laboratory to develop viable energy technologies enabling the CO2 capture from large stationary point sources. Solid, immobilized amine sorbents (IAS) formulated by impregnation of liquid amines within porous substrates are reactive towards CO2 and offer an alternative means for cyclic capture of CO2 eliminating, to some degree, inadequacies related to chemical absorption by aqueous alkanolamine solutions. This paper describes synthesis, characterization, and CO2 adsorption properties for IAS materials previously tested to bind and release CO2 and water vapor in a closed loop life support system. Tetraethylenepentamine (TEPA), acrylonitrile-modified tetraethylenepentamine (TEPAN), and a single formulation consisting of TEPAN and N, N’-bis(2-hydroxyethyl)ethylenediamine (BED) were individually supported on a poly (methyl methacrylate) (PMMA) substrate and examined. CO2 adsorption profiles leading to reversible CO2 adsorption capacities were obtained using thermogravimetry. Under 10% CO2 in nitrogen at 25°C and 1 atm, TEPA supported on PMMA over 60 minutes adsorbed ~3.2 mmol/g{sorbent} whereas, TEPAN supported on PMMA along with TEPAN and BED supported on PMMA adsorbed ~1.7 mmol/g{sorbent} and ~2.3 mmol/g{sorbent} respectively. Cyclic experiments with a 1:1 weight ratio of TEPAN and BED supported on poly (methyl methacrylate) beads utilizing a fixed-bed flow system with 9% CO2, 3.5% O2, nitrogen balance with trace gas constituents were studied. CO2 adsorption capacity was ~ 3 mmols CO2/g{sorbent} at 40°C and 1.4 atm. No beneficial effect on IAS performance was found using a moisture-laden flue gas mixture. Tests with 750 ppmv NO in a humidified gas stream revealed negligible NO sorption onto the IAS. A high SO2

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

    NASA Astrophysics Data System (ADS)

    Lac, C.; Donnelly, R. P.; Masson, V.; Pal, S.; Donier, S.; Queguiner, S.; Tanguy, G.; Ammoura, L.; Xueref-Remy, I.

    2012-10-01

    Accurate simulation of the spatial and temporal variability of tracer mixing ratios over urban areas is challenging, but essential in order to utilize CO2 measurements in an atmospheric inverse framework 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 between the surface and the atmosphere. Statistical scores show a good representation of the Urban Heat Island (UHI) and urban-rural contrasts. Boundary layer heights (BLH) at urban, sub-urban and rural sites are well captured, especially the onset time of the BLH increase and its growth rate in the morning, that are essential for tall tower CO2 observatories. Only nocturnal BLH at sub-urban sites are slightly underestimated a few nights, with a bias less than 50 m. At 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. The timing of the CO2 cycle is well captured by the model, with only small biases on CO2 concentrations, mainly linked to the misrepresentation of anthropogenic emissions, as the Eiffel site is at the heart of trafic emission sources. At sub-urban ground stations, CO2 measurements exhibit maxima at the beginning and at the end of each night, when the ABL is fully contracted, with a very strong spatio-temporal variability. The CO2 cycle at these sites is generally well reproduced by the model, even if some biases on the nocturnal maxima appear in the Paris plume parly due to small errors on the vertical transport, or in

  11. Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) Aircraft Measurements of CO2

    NASA Technical Reports Server (NTRS)

    Christensen, Lance E.; Spiers, Gary D.; Menzies, Robert T.; Jacob, Joseph C.; Hyon, Jason

    2011-01-01

    The Jet Propulsion Laboratory Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) utilizes Integrated Path Differential Absorption (IPDA) at 2.05 microns to obtain CO2 column mixing ratios weighted heavily in the boundary layer. CO2LAS employs a coherent detection receiver and continuous-wave Th:Ho:YLF laser transmitters with output powers around 100 milliwatts. An offset frequency-locking scheme coupled to an absolute frequency reference enables the frequencies of the online and offline lasers to be held to within 200 kHz of desired values. We describe results from 2009 field campaigns when CO2LAS flew on the Twin Otter. We also describe spectroscopic studies aimed at uncovering potential biases in lidar CO2 retrievals at 2.05 microns.

  12. Flash scanning the CO2 laser: a revival of the CO2 laser in plastic surgery

    NASA Astrophysics Data System (ADS)

    Lach, Elliot

    1994-09-01

    The CO2 laser has broad clinical application yet also presents a number of practical disadvantages. These drawbacks have limited the success and utilization of this laser in plastic surgery. Flashscanner technology has recently been used for char-free CO2 laser surgery of the oropharynx, the external female genital tract, and perirectal mucosa. A commercially available optomechanical flashscanner unit `Swiftlase,' was adapted to a CO2 laser and used for treatment in numerous plastic surgical applications. Conditions and situations that were treated in this study included generalized neurofibromatosis, tuberous sclerosis, rhinophyma, viral warts, breast reconstruction, and deepithelialization prior to microsurgery or local flap transfer and/or skin graft placement. There were no significant wound healing complications. Some patients previously sustained undue scarring from conventional CO2 laser surgery. Conservative, primarily ablative CO2 laser surgery with the Swiftlase has usefulness for treatment of patients in plastic surgery including those that were previously unsuccessfully treated.

  13. CO2 laser used in cosmetology

    NASA Astrophysics Data System (ADS)

    Su, Chenglie

    1993-03-01

    Cases of various kinds of warts, nevi, papillomas, skin angiomas, ephilises, skin vegetation, scars and brandy noses were vaporized and solidified with a 2.5 - 8 W low power CO2 laser with an overall satisfaction rate up to 99.8% and the satisfaction rate for one time 92%.

  14. Agriculture waste and rising CO2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Currently, there are many uncertainties concerning agriculture’s role in global environmental change including the effects of rising atmospheric CO2 concentration. A viable and stable world food supply depends on productive agricultural systems, but environmental concerns within agriculture have to...

  15. Bosch CO2 Reduction System Development

    NASA Technical Reports Server (NTRS)

    Holmes, R. F.; King, C. D.; Keller, E. E.

    1976-01-01

    Development of a Bosch process CO2 reduction unit was continued, and, by means of hardware modifications, the performance was substantially improved. Benefits of the hardware upgrading were demonstrated by extensive unit operation and data acquisition in the laboratory. This work was accomplished on a cold seal configuration of the Bosch unit.

  16. Porous Hexacyanometalates for CO2 capture applications

    SciTech Connect

    Motkuri, Radha K.; Thallapally, Praveen K.; McGrail, B. Peter

    2013-07-30

    Prussian blue analogues of M3[Fe(CN)6]2 x H2O (where M=Fe, Mn and Ni) were synthesized, characterized and tested for their gas sorption capabilities. The sorption studies reveal that, these Prussian blue materials preferentially sorb CO2 over N2 and CH4 at low pressure (1bar).

  17. Blackbody-pumped CO2 laser experiment

    NASA Astrophysics Data System (ADS)

    Christiansen, W. H.; Insuik, R. J.

    1983-07-01

    Thermal radiation from a high temperature oven was used as an optical pump to achieve lasing from CO2 mixtures. Laser output as a function of blackbody temperature and gas conditions is described. This achievement represents the first blackbody cavity pumped laser and has potential for solar pumping. Previously announced in STAR as N83-10420

  18. 76 FR 43489 - Deferral for CO2

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-20

    ... dioxide CO 2 e carbon dioxide equivalents EO Executive Order EPA U.S. Environmental Protection Agency FR... the national inventory, see 74 FR 55351, under the definition for ``carbon dioxide equivalent.'' We... Prevention of Significant Deterioration (PSD) and Title V permitting requirements to biogenic carbon...

  19. Artificial photosynthesis - CO2 towards methanol

    NASA Astrophysics Data System (ADS)

    Nazimek, D.; Czech, B.

    2011-03-01

    The new insight into the problem of carbon dioxide utilization into valuable compound - methanol and then its transformation into fuel is presented. Because the highly endothermic requirements of the reaction of CO2 hydrogenation a photocatalytic route is applied. Combining of the two reactions: water splitting and CO2 hydrogenation using H2O as a source of hydrogen at the same time and place are proposed. The studies over modified TiO2 catalysts supported on Al2O3 were conducted in a self-designed circulated photocatalytic reaction system under at room temperature and constant pressure. Experimental results indicated that the highest yield of the photoreduction of CO2 with H2O were obtained using TiO2 with the active anatase phase modified by Ru and WO3 addition. The conversion was very high - almost 97% of CO2 was transformed mainly into methanol (14%vol.) and into small amount of formic and acetic acid and ester.

  20. Nuclear-pumped CO2 laser

    NASA Technical Reports Server (NTRS)

    Rowe, M.

    1979-01-01

    The He-3 (n,p)T reaction was examined as an energy source for a CO2 laser. For this purpose He-3 was added to a functioning CO2 electrically excited laser. Initially the laser was run electrically with 12 torr total pressure. The gas mixture was 1:1:8, CO2:N2:He. At zero reactor power, the laser was tested in place next to the core of the Georgia Tech. Research Reactor. After verification of laser action He-3 was added to the system. The He-3 partial pressures of 10 torr, 50 torr, and 300 torr were added in three separate reactor runs. Reactor power ranged from zero to 5 million watts, which corresponds to a peak flux of 10 to the 14th power/sq cm. At reactor powers greater than 10 kW, gain of up to 30 percent was shown. However, indications are this may be due to gamma excitation rather than caused by the He-3 (n,p)T reaction. These results do agree with the data of past CO2 nuclear pumped laser experiments.

  1. Detection of CO2 leakage by the surface-soil CO2-concentration monitoring (SCM) system in a small scale CO2 release test

    NASA Astrophysics Data System (ADS)

    Chae, Gitak; Yu, Soonyoung; Sung, Ki-Sung; Choi, Byoung-Young; Park, Jinyoung; Han, Raehee; Kim, Jeong-Chan; Park, Kwon Gyu

    2015-04-01

    Monitoring of CO2 release through the ground surface is essential to testify the safety of CO2 storage projects. We conducted a feasibility study of the multi-channel surface-soil CO2-concentration monitoring (SCM) system as a soil CO2 monitoring tool with a small scale injection. In the system, chambers are attached onto the ground surface, and NDIR sensors installed in each chamber detect CO2 in soil gas released through the soil surface. Before injection, the background CO2 concentrations were measured. They showed the distinct diurnal variation, and were positively related with relative humidity, but negatively with temperature. The negative relation of CO2 measurements with temperature and the low CO2 concentrations during the day imply that CO2 depends on respiration. The daily variation of CO2 concentrations was damped with precipitation, which can be explained by dissolution of CO2 and gas release out of pores through the ground surface with recharge. For the injection test, 4.2 kg of CO2 was injected 1 m below the ground for about 30 minutes. In result, CO2 concentrations increased in all five chambers, which were located less than 2.5 m of distance from an injection point. The Chamber 1, which is closest to the injection point, showed the largest increase of CO2 concentrations; while Chamber 2, 3, and 4 showed the peak which is 2 times higher than the average of background CO2. The CO2 concentrations increased back after decreasing from the peak around 4 hours after the injection ended in Chamber 2, 4, and 5, which indicated that CO2 concentrations seem to be recovered to the background around 4 hours after the injection ended. To determine the leakage, the data in Chamber 2 and 5, which had low increase rates in the CO2 injection test, were used for statistical analysis. The result shows that the coefficient of variation (CV) of CO2 measurements for 30 minutes is efficient to determine a leakage signal, with reflecting the abnormal change in CO2

  2. Isolation of microorganisms from CO2 sequestration sites through enrichments under high pCO2

    NASA Astrophysics Data System (ADS)

    Peet, K. C.; Freedman, A. J.; Boreham, C.; Thompson, J. R.

    2012-12-01

    Carbon Capture and Storage (CCS) in geologic formations has the potential to reduce greenhouse gas emissions from fossil fuel processing and combustion. However, little is known about the effects that CO2 may have on biological activity in deep earth environments. To understand microorganisms associated with these environments, we have developed a simple high-pressure enrichment methodology to cultivate organisms capable of growth under supercritical CO2 (scCO2). Growth media targeting different subsurface functional metabolic groups is added to sterilized 316 stainless steel tubing sealed with quarter turn plug valves values and pressurized to 120-136 atm using a helium-padded CO2 tank, followed by incubation at 37 °C to achieve the scCO2 state. Repeated passages of crushed subsurface rock samples and growth media under supercritical CO2 headspaces are assessed for growth via microscopic enumeration. We have utilized this method to survey sandstone cores for microbes capable of growth under scCO2 from two different geologic sites targeted for carbon sequestration activities. Reproducible growth of microbial biomass under high pCO2 has been sustained from each site. Cell morphologies consist of primarily 1-2 μm rods and oval spores, with densities from 1E5-1E7 cells per ml of culture. We have purified and characterized a bacterial strain most closely related to Bacillus subterraneus (99% 16S rRNA identity) capable of growth under scCO2. Preliminary physiological characterization of this strain indicates it is a spore-forming facultative anaerobe able to grow in 0.5 to 50 ppt salinity. Genome sequencing and analysis currently in progress will help reveal genetic mechanisms of acclimation to high pCO2 conditions associated with geologic carbon sequestration.

  3. Sustained effects of atmospheric [CO2] and nitrogen availability on forest soil CO2 efflux.

    PubMed

    Oishi, A Christopher; Palmroth, Sari; Johnsen, Kurt H; McCarthy, Heather R; Oren, Ram

    2014-04-01

    Soil CO2 efflux (Fsoil ) is the largest source of carbon from forests and reflects primary productivity as well as how carbon is allocated within forest ecosystems. Through early stages of stand development, both elevated [CO2] and availability of soil nitrogen (N; sum of mineralization, deposition, and fixation) have been shown to increase gross primary productivity, but the long-term effects of these factors on Fsoil are less clear. Expanding on previous studies at the Duke Free-Air CO2 Enrichment (FACE) site, we quantified the effects of elevated [CO2] and N fertilization on Fsoil using daily measurements from automated chambers over 10 years. Consistent with previous results, compared to ambient unfertilized plots, annual Fsoil increased under elevated [CO2] (ca. 17%) and decreased with N (ca. 21%). N fertilization under elevated [CO2] reduced Fsoil to values similar to untreated plots. Over the study period, base respiration rates increased with leaf productivity, but declined after productivity saturated. Despite treatment-induced differences in aboveground biomass, soil temperature and water content were similar among treatments. Interannually, low soil water content decreased annual Fsoil from potential values - estimated based on temperature alone assuming nonlimiting soil water content - by ca. 0.7% per 1.0% reduction in relative extractable water. This effect was only slightly ameliorated by elevated [CO2]. Variability in soil N availability among plots accounted for the spatial variability in Fsoil , showing a decrease of ca. 114 g C m(-2) yr(-1) per 1 g m(-2) increase in soil N availability, with consistently higher Fsoil in elevated [CO2] plots ca. 127 g C per 100 ppm [CO2] over the +200 ppm enrichment. Altogether, reflecting increased belowground carbon partitioning in response to greater plant nutritional needs, the effects of elevated [CO2] and N fertilization on Fsoil in this stand are sustained beyond the early stages of stand development and

  4. The Role of the CO2 Laser and Fractional CO2 Laser in Dermatology

    PubMed Central

    Omi, Tokuya; Numano, Kayoko

    2014-01-01

    Background: Tremendous advances have been made in the medical application of the laser in the past few decades. Many diseases in the dermatological field are now indications for laser treatment that qualify for reimbursement by many national health insurance systems. Among laser types, the carbon dioxide (CO2) laser remains an important system for the dermatologist. Rationale: The lasers used in photosurgery have wavelengths that differ according to their intended use and are of various types, but the CO2 laser is one of the most widely used lasers in the dermatology field. With its wavelength in the mid-infrared at 10,600 nm, CO2 laser energy is wellabsorbed in water. As skin contains a very high water percentage, this makes the CO2 laser ideal for precise, safe ablation with good hemostasis. In addition to its efficacy in ablating benign raised lesions, the CO2 laser has been reported to be effective in the field of esthetic dermatology in the revision of acne scars as well as in photorejuvenation. With the addition of fractionation of the beam of energy into myriad microbeams, the fractional CO2 laser has offered a bridge between the frankly full ablative indications and the nonablative skin rejuvenation systems of the 2000s in the rejuvenation of photoaged skin on and off the face. Conclusions: The CO2 laser remains an efficient, precise and safe system for the dermatologist. Technological advances in CO2 laser construction have meant smaller spot sizes and greater precision for laser surgery, and more flexibility in tip sizes and protocols for fractional CO2 laser treatment. The range of dermatological applications of the CO2 laser is expected to continue to increase in the future. PMID:24771971

  5. Vadose Zone Remediation of CO2 Leakage from Geologic CO2 Storage Sites

    SciTech Connect

    Zhang, Yingqi; Oldenburg, Curtis M.; Benson, Sally M.

    2004-03-03

    In the unlikely event that CO2 leakage from deep geologic CO2 sequestration sites reaches the vadose zone, remediation measures for removing the CO2 gas plume may have to be undertaken. Carbon dioxide leakage plumes are similar in many ways to volatile organic compound (VOC) vapor plumes, and the same remediation approaches are applicable. We present here numerical simulation results of passive and active remediation strategies for CO2 leakage plumes in the vadose zone. The starting time for the remediation scenarios is assumed to be after a steady-state CO2 leakage plume is established in the vadose zone, and the source of this plume has been cut off. We consider first passive remediation, both with and without barometric pumping. Next, we consider active methods involving extraction wells in both vertical and horizontal configurations. To compare the effectiveness of the various remediation strategies, we define a half-life of the CO2 plume as a convenient measure of the CO2 removal rate. For CO2 removal by passive remediation approaches such as barometric pumping, thicker vadose zones generally require longer remediation times. However, for the case of a thin vadose zone where a significant fraction of the CO2 plume mass resides within the high liquid saturation region near the water table, the half-life of the CO2 plume without barometric pumping is longer than for somewhat thicker vadose zones. As for active strategies, results show that a combination of horizontal and vertical wells is the most effective among the strategies investigated, as the performance of commonly used multiple vertical wells was not investigated.

  6. Modelling the Martian CO2 Ice Clouds

    NASA Astrophysics Data System (ADS)

    Listowski, Constantino; Määttänen, A.; Montmessin, F.; Lefèvre, F.

    2012-10-01

    Martian CO2 ice cloud formation represents a rare phenomenon in the Solar System: the condensation of the main component of the atmosphere. Moreover, on Mars, condensation occurs in a rarefied atmosphere (large Knudsen numbers, Kn) that limits the growth efficiency. These clouds form in the polar winter troposphere and in the mesosphere near the equator. CO2 ice cloud modeling has turned out to be challenging: recent efforts (e.g. [1]) fail in explaining typical small sizes (80 nm-130 nm) observed for mesospheric clouds [2]. Supercold pockets (T<< Tcond), which appear to be common in the mesosphere [3],might be exclusively responsible of the formation of such clouds, as a consequence of gravity waves propagating throughout the atmosphere [4]. In order to understand by modeling the effect CO2 clouds could have on the Martian climate, one needs to properly predict the crystal sizes, and so the growth rates involved. We will show that Earth microphysical crystal growth models, which deal with the condensation of trace gases, are misleading when transposed for CO2 cloud formation: they overestimate the growth rates at high saturation ratios. On the other hand, an approach based on the continuum regime (small Kn), corrected to account for the free molecular regime (high Kn) remains efficient. We present our new approach for modelling the growth of Martian CO2 cloud crystals, investigated with a 1D-microphysical model. [1] Colaprete, A., et al., (2008) PSS, 56, 150C [2] Montmessin, F., et al., (2006) Icarus, 183, 403-410 [3] Montmessin at al., (2011) mamo, 404-405 [4] Spiga, A., et al., (2012), GRL, 39, L02201 [5] Wood, S. E., (1999), Ph.D. thesis, UCLA [6] Young, J. B., J. Geophys. Res., 36, 294-2956, 1993

  7. CO2 Orbital Trends in Comets

    NASA Astrophysics Data System (ADS)

    Kelley, Michael; Feaga, Lori; Bodewits, Dennis; McKay, Adam; Snodgrass, Colin; Wooden, Diane

    2014-12-01

    Spacecraft missions to comets return a treasure trove of details of their targets, e.g., the Rosetta mission to comet 67P/Churyumov-Gerasimenko, the Deep Impact experiment at comet 9P/Tempel 1, or even the flyby of C/2013 A1 (Siding Spring) at Mars. Yet, missions are rare, the diversity of comets is large, few comets are easily accessible, and comet flybys essentially return snapshots of their target nuclei. Thus, telescopic observations are necessary to place the mission data within the context of each comet's long-term behavior, and to further connect mission results to the comet population as a whole. We propose a large Cycle 11 project to study the long-term activity of past and potential future mission targets, and select bright Oort cloud comets to infer comet nucleus properties, which would otherwise require flyby missions. In the classical comet model, cometary mass loss is driven by the sublimation of water ice. However, recent discoveries suggest that the more volatile CO and CO2 ices are the likely drivers of some comet active regions. Surprisingly, CO2 drove most of the activity of comet Hartley 2 at only 1 AU from the Sun where vigorous water ice sublimation would be expected to dominate. Currently, little is known about the role of CO2 in comet activity because telluric absorptions prohibit monitoring from the ground. In our Cycle 11 project, we will study the CO2 activity of our targets through IRAC photometry. In conjunction with prior observations of CO2 and CO, as well as future data sets (JWST) and ongoing Earth-based projects led by members of our team, we will investigate both long-term activity trends in our target comets, with a particular goal to ascertain the connections between each comet's coma and nucleus.

  8. CO2 monitoring at the pilot-scale CO2 injection site in Nagaoka, Japan

    NASA Astrophysics Data System (ADS)

    Tanase, D.; Xue, Z.; Watanabe, J.; Saito, H.

    2005-12-01

    A pilot-scale CO2 sequestration project supported by the Japanese Government (METI) has been conducted by Research Institute of Innovative Technology for the Earth (RITE) in co-operation with Engineering Advancement Association of Japan (ENAA). The test site is located at the South Nagaoka gas field operated by Teikoku Oil Co., Ltd. in Nagaoka city, Niigata Prefecture, 200 km north of Tokyo. The targeted layer for the CO2 injection is a thin permeable zone intercalated in a 60 m thick sandstone bed of early Pleistocene age, which lies about 1,100 m below the ground surface. One injection well (IW-1) and three observation wells (OB-2, -3, -4) were drilled at the site. The CO2 injection started on 7 July 2003 and ended on 11 January 2005 with the total injected amount of 10,400 tonnes within eighteen months. Purchased CO2 of 99.9 % pure was injected in the supercritical state at the rate of 20-40 tonnes per day. A series of time-lapse CO2 monitoring consisted of geophysical well logging and cross-well seismic tomography has been performed at the injection site and the results provide valuable insight into the CO2 movement in the sandstone reservoir. Time-lapse well loggings of induction, gamma ray, neutron and sonic were performed almost once a month to monitor CO2 breakthrough at the three observation wells. On 10 March 2004, a breakthrough was first detected at OB-2, 40 m apart from the injection well, after the cumulative injection of 4,000 tonnes. As an evidence of CO2 breakthrough changes appeared in results of sonic, induction and neutron logs. The sonic P-wave velocity decreased significantly up to 23% after the breakthrough, and then results of sonic logging showed the CO2-bearing zone getting wider during the injection of CO2. Differences appeared also in widths of CO2-bearing zone of induction and neutron logs. On 16 July 2004, another breakthrough of CO2 was detected at OB-4 of 60 m away from the injection well as changes in sonic and neutron logs. No sign

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

    NASA Astrophysics Data System (ADS)

    Lac, C.; Donnelly, R. P.; Masson, V.; Pal, S.; Riette, S.; Donier, S.; Queguiner, S.; Tanguy, G.; Ammoura, L.; Xueref-Remy, I.

    2013-05-01

    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 sensitivity test without

  10. Molecular Behavior CO2 and CO2-H2O Mixtures at Interfaces

    NASA Astrophysics Data System (ADS)

    Cole, D. R.; Chialvo, A.; Rother, G.; Vlcek, L.

    2010-12-01

    Injection of CO2 into subsurface geologic formations has been identified as a key strategy for mitigating the impact of anthropogenic emissions of CO2. Regardless of the formation type, the CO2 will encounter a complex heterogeneous porous matrix with widely varying pore size and pore distribution, interconnectivity, and surface composition. A small but non-trivial percentage of the pore space is comprised of voids that range from 100 nm down to a few nm in size. These nanoporous environments are more dominant in the cap or seal rocks, such as shale or clay-rich mudstones that act as confining barriers to leakage of CO2 out of the storage reservoir. A concern is the prevention of leakage from the host formation by an effective cap or seal rock which has low porosity and permeability characteristics. Shales comprise the majority of cap rocks encountered in subsurface injection sites with pore sizes typically less than 100 nm and whose surface chemistries are dominated by quartz (SiO2) and clays. We investigated the behavior of pure CO2 and CO2-H2O mixtures interacting with simple substrates, e.g. SiO2 and muscovite, that act as proxies for more complex mineralogical systems. SANS results were described for sorption properties of supercritical CO2 inside mesoporous silica aerogel (95% porosity; 5-40 nm pores), a proxy for the quartz sub-system. The Adsorbed Phase Model (APM) allows, for the first time, a means to quantify the physical properties (e.g. excess, absolute and total adsorption) of the adsorbed phase formed by fluids inside porous media in terms of the mean density and volume of the sorption phase. The results show clear evidence for fluid depletion for conditions above the critical density. Classical molecular dynamics (CMD) modeling of CO2-silica aerogel interactions also indicates the presence of fluid depletion for conditions above the critical density consistent with SANS results. CMD was also used to assess the microscopic behavior of CO2-H2O mixture

  11. Root-derived CO2 efflux via xylem stream rivals soil CO2 efflux.

    SciTech Connect

    Aubrey, Doug, P.; Teskey, Robert, O.

    2009-07-01

    • Respiration consumes a large portion of annual gross primary productivity in forest ecosystems and is dominated by belowground metabolism. Here, we present evidence of a previously unaccounted for internal CO2 flux of large magnitude from tree roots through stems. If this pattern is shown to persist over time and in other forests, it suggests that belowground respiration has been grossly underestimated. • Using an experimental Populus deltoides plantation as a model system, we tested the hypothesis that a substantial portion of the CO2 released from belowground autotrophic respiration remains within tree root systems and is transported aboveground through the xylem stream rather than diffusing into the soil atmosphere. • On a daily basis, the amount of CO2 that moved upward from the root system into the stem via the xylem stream (0.26 mol CO2 m-2 d-1) rivalled that which diffused from the soil surface to the atmosphere (0.27 mol CO2 m-2 d-1). We estimated that twice the amount of CO2 derived from belowground autotrophic respiration entered the xylem stream as diffused into the soil environment. • Our observations indicate that belowground autotrophic respiration consumes substantially more carbohydrates than previously recognized and challenge the paradigm that all root-respired CO2 diffuses into the soil atmosphere.

  12. CO2-helium and CO2-neon mixtures at high pressures.

    PubMed

    Mallick, B; Ninet, S; Le Marchand, G; Munsch, P; Datchi, F

    2013-01-28

    The properties of mixtures of carbon dioxide with helium or neon have been investigated as a function of CO(2) concentration and pressure up to 30 GPa at room temperature. The binary phase diagrams of these mixtures are determined over the full range of CO(2) concentrations using visual observations and Raman scattering measurements. Both diagrams are of eutectic type, with a fluid-fluid miscibility gap for CO(2) concentrations in the range [5, 75] mol. % for He and [8, 55] mol. % for Ne, and a complete separation between the two components in the solid phase. The absence of alloys or stoichiometric compounds for these two binary systems is consistent with the Hume-Rothery rules of hard sphere mixtures. The Raman spectra and x-ray diffraction patterns of solid CO(2) embedded in He or Ne for various initial concentrations have been measured up to 30 GPa and 12 GPa, respectively. The frequencies of the Raman modes and the volume of solid phase I are identical, within error bars, to those reported for 100% CO(2) samples, thus confirming the total immiscibility of CO(2) with He and Ne in the solid phase. These results demonstrate the possibility to perform high-pressure experiments on solid CO(2) under (quasi-)hydrostatic conditions using He or Ne as pressure transmitting medium. PMID:23387603

  13. Photosynthetic CO2 uptake in seedlings of two tropical tree species exposed to oscillating elevated concentrations of CO2.

    PubMed

    Holtum, Joseph A M; Winter, Klaus

    2003-11-01

    Do short-term fluctuations in CO2 concentrations at elevated CO2 levels affect net CO2 uptake rates of plants? When exposed to 600 microl CO2 l(-1), net CO2 uptake rates in shoots or leaves of seedlings of two tropical C3 tree species, teak (Tectona grandis L. f.) and barrigon [Pseudobombax septenatum (Jacq.) Dug.], increased by 28 and 52% respectively. In the presence of oscillations with half-cycles of 20 s, amplitude of ca. 170 microl CO2 l(-1) and mean of 600 microl CO2 l(-1), the stimulation in net CO2 uptake by the two species was reduced to 19 and 36%, respectively, i.e. the CO2 stimulation in photosynthesis associated with a change in exposure from 370 to 600 microl CO2 l(-1) was reduced by a third in both species. Similar reductions in CO2-stimulated net CO2 uptake were observed in T. grandis exposed to 40-s oscillations. Rates of CO2 efflux in the dark by whole shoots of T. grandis decreased by 4.8% upon exposure of plants grown at 370 microl CO2 l(-1) to 600 microl CO2 l(-1). The potential implications of the observations on CO2 oscillations and dark respiration are discussed in the context of free-air CO2 enrichment (FACE) systems in which short-term fluctuations of CO2 concentration are a common feature. PMID:12905026

  14. Geochemical Interaction of Middle Bakken Reservoir Rock and CO2 during CO2-Based Fracturing

    NASA Astrophysics Data System (ADS)

    Nicot, J. P.; Lu, J.; Mickler, P. J.; Ribeiro, L. H.; Darvari, R.

    2015-12-01

    This study was conducted to investigate the effects of geochemical interactions when CO2 is used to create the fractures necessary to produce hydrocarbons from low-permeability Middle Bakken sandstone. The primary objectives are to: (1) identify and understand the geochemical reactions related to CO2-based fracturing, and (2) assess potential changes of reservoir property. Three autoclave experiments were conducted at reservoir conditions exposing middle Bakken core fragments to supercritical CO2 (sc-CO2) only and to CO2-saturated synthetic brine. Ion-milled core samples were examined before and after the reaction experiments using scanning electron microscope, which enabled us to image the reaction surface in extreme details and unambiguously identify mineral dissolution and precipitation. The most significant changes in the reacted rock samples exposed to the CO2-saturated brine is dissolution of the carbonate minerals, particularly calcite which displays severely corrosion. Dolomite grains were corroded to a lesser degree. Quartz and feldspars remained intact and some pyrite framboids underwent slight dissolution. Additionally, small amount of calcite precipitation took place as indicated by numerous small calcite crystals formed at the reaction surface and in the pores. The aqueous solution composition changes confirm these petrographic observations with increase in Ca and Mg and associated minor elements and very slight increase in Fe and sulfate. When exposed to sc-CO2 only, changes observed include etching of calcite grain surface and precipitation of salt crystals (halite and anhydrite) due to evaporation of residual pore water into the sc-CO2 phase. Dolomite and feldspars remained intact and pyrite grains were slightly altered. Mercury intrusion capillary pressure tests on reacted and unreacted samples shows an increase in porosity when an aqueous phase is present but no overall porosity change caused by sc-CO2. It also suggests an increase in permeability

  15. The Relationship Between CO2 Levels and CO2 Related Symptoms Reported on the ISS

    NASA Technical Reports Server (NTRS)

    VanBaalen, M.; Law, J.; Foy, M.; Wear, M. L.; Mason, S.; Mendez, C.; Meyers, V.

    2014-01-01

    Medical Operations, Toxicology, and the Lifetime Surveillance of Astronaut Health collaborated to assess the association of CO2 levels on board the International Space Station and USOS crew reported symptoms inflight, i.e. headache and vision changes. Private Medical Conference (PMC) documents and the weekly Space Medicine Operations Team (SMOT) Notes were used to provide a robust data set of inflight medical events. All events and non-events were documented independent of CO2 levels and other potential contributors. Average (arithmetic mean) and single point maximum ppCO2 was calculated for the 24 hours and 7 days prior to the PMC or SMOT date and time provided by LSAH. Observations falling within the first 7 days of flight (147) were removed from the datasets analyzed to avoid confounding with Space Adaptation Syndrome. The final analysis was based on 1716 observations. For headache, 46 headaches were observed. CO2 level, age at launch, time inflight, and data source were all significantly associated with headache. In particular, for each 1 mmHg increase in CO2, the odds of a crewmember reporting a headache doubled. For vision changes, 29 reports of vision changes were observed. These observations were not found to be statistically associated with CO2 levels as analyzed. While the incidence of headache has was not high (3%), headaches may be an indicator of underlying increases in intracranial pressure, which may result likely from the synergy between CO2-induced cerebral vasodilatation and decreased venous drainage in microgravity. Vision changes were inconsistently reported and as a result did not align appropriately with the CO2 levels. Further analysis is needed. Our results support ongoing efforts to lower the CO2 exposure limits in spacecraft.

  16. CO2 mineralization-bridge between storage and utilization of CO2.

    PubMed

    Geerlings, Hans; Zevenhoven, Ron

    2013-01-01

    CO2 mineralization comprises a chemical reaction between suitable minerals and the greenhouse gas carbon dioxide. The CO2 is effectively sequestered as a carbonate, which is stable on geological timescales. In addition, the variety of materials that can be produced through mineralization could find applications in the marketplace, which makes implementation of the technology more attractive. In this article, we review recent developments and assess the current status of the CO2 mineralization field. In an outlook, we briefly describe a few mineralization routes, which upon further development have the potential to be implemented on a large scale. PMID:23452171

  17. Effects of CO2 on stomatal conductance: do stomata open at very high CO2 concentrations?

    NASA Technical Reports Server (NTRS)

    Wheeler, R. M.; Mackowiak, C. L.; Yorio, N. C.; Sager, J. C.

    1999-01-01

    Potato and wheat plants were grown for 50 d at 400, 1000 and 10000 micromoles mol-1 carbon dioxide (CO2). and sweetpotato and soybean were grown at 1000 micromoles mol-1 CO2 in controlled environment chambers to study stomatal conductance and plant water use. Lighting was provided with fluorescent lamps as a 12 h photoperiod with 300 micromoles m-2 s-1 PAR. Mid-day stomatal conductances for potato were greatest at 400 and 10000 micromoles mol-1 and least at 1000 micromoles mol-1 CO2. Mid-day conductances for wheat were greatest at 400 micromoles mol-1 and least at 1000 and 10000 micromoles mol-1 CO2. Mid-dark period conductances for potato were significantly greater at 10000 micromoles mol-1 than at 400 or 1000 micromoles mol-1, whereas dark conductance for wheat was similar in all CO2 treatments. Temporarily changing the CO2 concentration from the native 1000 micromoles mol-1 to 400 micromoles mol-1 increased mid-day conductance for all species, while temporarily changing from 1000 to 10000 micromoles mol-1 also increased conductance for potato and sweetpotato. Temporarily changing the dark period CO2 from 1000 to 10000 micromoles mol-1 increased conductance for potato, soybean and sweetpotato. In all cases, the stomatal responses were reversible, i.e. conductances returned to original rates following temporary changes in CO2 concentration. Canopy water use for potato was greatest at 10000, intermediate at 400, and least at 1000 micromoles mol-1 CO2, whereas canopy water use for wheat was greatest at 400 and similar at 1000 and 10000 micromoles mol-1 CO2. Elevated CO2 treatments (i.e. 1000 and 10000 micromoles mol-1) resulted in increased plant biomass for both wheat and potato relative to 400 micromoles mol-1, and no injurious effects were apparent from the 10000 micromoles mol-1 treatment. Results indicate that super-elevated CO2 (i.e. 10000 micromoles mol-1) can increase stomatal conductance in some species, particularly during the dark period, resulting in

  18. CO2 permeability of fractured cap rocks - experiments and numerical simulations (CO2Seals)

    NASA Astrophysics Data System (ADS)

    (Draeger), Ines Rick; Clauser, Christoph

    2010-05-01

    In CO2 sequestration and underground gas storage the sealing capacity of a cap rock is of paramount importance. The main question is therefore how the leakage of CO2 through fissures and faults within the cap rock may affect the CO2 sealing efficiency of low-permeable seal lithotypes. In many cases, these structures provide the main pathways for leakage of CO2. Here, we provide an overview of one part of the joint research project CO2Seals, which deals with the effect of structural features - such as tectonic faults and fissures in the overburden - on the migration of CO2 in addition to mineralogical, petrophysical, and geochemical properties of different lithotypes. The primary contribution of the entire project consists of an improvement of the present quantitative understanding of CO2 transport and retention processes and associated interactions in cap rocks between rock and CO2 or brine. To this end, we are adapting different numerical tools for simulating the relevant petrophysical and geochemical processes of CO2 in cap rocks, in close operation with: (1) large-scale CO2-percolation experiments on fractured cap rock samples; (2) permeability, gas breakthrough, and diffusion experiments; (3) measurements of the mechanical stability of cap rocks and the geochemical alterations of fault zone rock. The observed resulting changes in petrophysical properties, such as porosity, relative rock permeability (CO2 and brine), and fault permeability provide basics for the following numerical simulations. For example, first permeability tests of a marl and clay cap rock out of Cretaceous and Jurassic formations revealed gas permeability of 10-18 m2 down to 10-22 m2. In addition, first percolation experiments indicated that the influence of fault zones on the measured CO2 permeability of clays is very low. Furthermore, numerical bench-scale models are performed to provide confidence for the subsequent transfer to reservoir systems. Large-scale numerical models were created

  19. Innovative Energy Strategies for CO2 Stabilization

    NASA Astrophysics Data System (ADS)

    Watts, Robert G.

    2002-08-01

    Many of the world's climate scientists believe that the build-up of heat-trapping CO2 in the atmosphere will lead to global warming unless we burn less fossil fuels. At the same time, energy must be supplied in increasing amounts for the developing world to continue its growth. This work discusses the feasibility of increasingly efficient energy use and the potential for supplying energy from sources that do not introduce CO2. The book analyzes the prospects for Earth-based renewables: solar, wind, biomass, hydroelectricity, geothermal and ocean energy. It then discusses nuclear fission and fusion, and the relatively new idea of harvesting solar energy on satellites or lunar bases. It will be essential reading for all those interested in energy issues.

  20. Effects of contaminants in CO2 lasers.

    NASA Technical Reports Server (NTRS)

    Smith, N. S.

    1973-01-01

    A theoretical model which includes the effects of contaminants is developed for the high flow electric discharge CO2-N2-He laser. The model couples the excitation and relaxation processes, CO2 dissociation, and negative ion formation with the flow processes. An analysis of the effects of CO, O2, NO, and N2O impurities on the average small signal gain is presented. CO decreases the gain by collisional depopulation of the upper laser level, and O2, NO, and N2O reduce the gain by decreasing the electron density by forming stable negative ions. In particular, N2O exhibits a strong quenching effect because of its large dissociation cross section for the formation of O(-).

  1. Ultraviolet photoionization in CO2 TEA lasers

    NASA Astrophysics Data System (ADS)

    Scott, S. J.; Smith, A. L. S.

    1988-07-01

    The effects of gas composition and spark parameters on the UV emission in CO2 TEA laser gas mixtures were investigated together with the nature of photoionization process and the photoelectron-loss mechanism. A linear relationship was found between N2 concentration and photoionization (with no such dependence on C concentration, from CO and CO2), but the increases in photoionization that could be effected by optimizing the spark discharge circuit parameters were much higher than those produced by changes in gas composition. UV emission was directly proportional to the amount of stored electrical energy in the spark-discharge circuit and to the cube of the peak current produced in the spark by the discharge of this energy. Photoionization was also found to be proportional to the spark electrode gap. It was found that free-space sparks gave a considerably broader emission pattern than a surface-guided notched spark.

  2. CO2 Impacts on the Martian Atmosphere

    NASA Astrophysics Data System (ADS)

    Kelley, Michael; Bauer, James; Bodewits, Dennis; Farnham, Tony; Stevenson, Rachel; Yelle, Roger

    2014-09-01

    The dynamically new comet C/2013 A1 (Siding Spring) will pass Mars at the extremely close distance of 140,000 km on 2014 Oct 19. This encounter is unique---a record close approach to a planet with spacecraft that can observe its passage---and currently, all 5 Mars orbiters have plans to observe the comet and/or its effects on the planet. Gas from the comet's coma is expected to collide with the Martian atmosphere, altering the abundances of some species and producing significant heating, inflating the upper atmosphere. We propose DDT observations with Spitzer/IRAC to measure the comet's CO2+CO coma (observing window Oct 30 - Nov 20), to use these measurements to derive the coma's CO2 density at Mars during the closest approach, and to aid the interpretation of any observed effects or changes in the Martian atmosphere.

  3. Increasing CO2 threatens human nutrition.

    PubMed

    Myers, Samuel S; Zanobetti, Antonella; Kloog, Itai; Huybers, Peter; Leakey, Andrew D B; Bloom, Arnold J; Carlisle, Eli; Dietterich, Lee H; Fitzgerald, Glenn; Hasegawa, Toshihiro; Holbrook, N Michele; Nelson, Randall L; Ottman, Michael J; Raboy, Victor; Sakai, Hidemitsu; Sartor, Karla A; Schwartz, Joel; Seneweera, Saman; Tausz, Michael; Usui, Yasuhiro

    2014-06-01

    Dietary deficiencies of zinc and iron are a substantial global public health problem. An estimated two billion people suffer these deficiencies, causing a loss of 63 million life-years annually. Most of these people depend on C3 grains and legumes as their primary dietary source of zinc and iron. Here we report that C3 grains and legumes have lower concentrations of zinc and iron when grown under field conditions at the elevated atmospheric CO2 concentration predicted for the middle of this century. C3 crops other than legumes also have lower concentrations of protein, whereas C4 crops seem to be less affected. Differences between cultivars of a single crop suggest that breeding for decreased sensitivity to atmospheric CO2 concentration could partly address these new challenges to global health. PMID:24805231

  4. Aerosol extinction measurements with CO2-lidar

    NASA Technical Reports Server (NTRS)

    Hagard, Arne; Persson, Rolf

    1992-01-01

    With the aim to develop a model for infrared extinction due to aerosols in slant paths in the lower atmosphere we perform measurements with a CO2-lidar. Earlier measurements with a transmissometer along horizontal paths have been used to develop relations between aerosol extinction and meteorological parameters. With the lidar measurements we hope to develop corresponding relations for altitude profiles of the aerosol extinction in the infrared. An important application is prediction of detection range for infrared imaging systems.

  5. Controls on the CO2 seasonal cycle

    NASA Technical Reports Server (NTRS)

    Pollack, J. B.; Forget, F.; Haberle, Robert M.; Schaeffer, J.; Lee, H.

    1993-01-01

    Surface pressure measurement performed by the Viking landers show substantial variations in pressure on seasonal timescales that are characterized by two local minima and two local maxima. These variations have widely been attributed to the seasonal condensation and sublimation of CO2 in the two polar regions. It has been somewhat of a surprise that the amplitude of the minimum and maximum that is dominated by the CO2 cycle in the north was much weaker than the corresponding amplitude of the south-dominated extrema. Another surprise was that the seasonal pressure cycle during years 2 and 3 of the Viking mission was so similar to that for year 1, despite the occurrence of two global dust storms during year 1 and none during years 2 and 3. An energy balance model that incorporates dynamical factors from general circulation model (GCM) runs in which the atmospheric dust opacity and seasonal date were systematically varied was used to model the observed seasonal pressure variations. The energy balance takes account of the following processes in determining the rates of CO2 condensation and sublimation at each longitudinal and latitudinal grid point: solar radiation, infrared radiation from the atmosphere and surface, subsurface heat conduction, and atmospheric heat advection. Condensation rates are calculated both at the surface and in the atmosphere. In addition, the energy balance model also incorporates information from the GCM runs on seasonal redistribution of surface pressure across the globe. Estimates of surface temperature of the seasonal CO2 caps were used to define the infrared radiative losses from the seasonal polar caps. The seasonal pressure variations measured at the Viking lander sites were closely reproduced.

  6. [Voice quality following CO2 laser cordectomy].

    PubMed

    Höfler, H; Bigenzahn, W

    1986-11-01

    The voice of patients after CO2 laser cordectomy was evaluated by subjective assessment, registration of voice parameters and sonegraphic classification. The results proved to be closely concordant, the main result being a slight or medium degree of dysphonia. Severe dysphonia or aphonia occurred in about one fifth of patients. This result is somewhat inferior to radiotherapy, but superior to standard translaryngeal cordectomy. Yanagihara's sonegraphic classification of dysphonia is recommendable for future comparative studies. PMID:3807602

  7. Continuous CO2 extractor and methods

    SciTech Connect

    None listed

    2010-06-15

    The purpose of this CRADA was to assist in technology transfer from Russia to the US and assist in development of the technology improvements and applications for use in the U.S. and worldwide. Over the period of this work, ORNL has facilitated design, development and demonstration of a low-pressure liquid extractor and development of initial design for high-pressure supercritical CO2 fluid extractor.

  8. CO2 laser cold cathode research results

    NASA Technical Reports Server (NTRS)

    Hochuli, U.

    1973-01-01

    The construction and processing of four test lasers are discussed, and the test results are assessed. Tests show that the best performance was obtained from cathodes made from internally oxidized Ag-Cu alloys or pure Cu. Due to the cold cathode technology developments, sealed-off 1 w CO2 lasers with gas volumes of only 50 cu cm were duplicated, and have performed satisfactorily for more than 6000 hours.

  9. Pulpotomies with CO2 laser in dogs

    NASA Astrophysics Data System (ADS)

    Figueiredo, Jose A. P.; Chavantes, Maria C.; Gioso, Marco A.; Pesce, Hildeberto F.; Jatene, Adib D.

    1995-05-01

    The aim of this study was to evaluate the clinical aspects of dental pulps submitted to shallow pulpotomy followed by CO2 laser radiation at five different procedures. For this purpose, initially 66 dogs' teeth were opened and about 2 or 3 mm of coronal dental pulp was removed. Continuous irrigation with saline solution was implemented. The teeth were randomly divided into 6 groups of 11 each. After cessation of bleeding, in group I, CO2 laser (Xanar-20, USA) was irradiated for 1 second at a power of 5 watts; in group II, 2 seconds at 3 watts; in Group III, 2 seconds at 5 watts; in Group IV, 1 second at 3 watts; in Group V, a continuous mode at 3 watts; Group VI served as a control, with no laser irradiation. The results showed no clinical differences between the 3 W and 5 W powers. Time period of irradiation exposition influenced definitively the clinical appearance of the dental pulps. Groups I and IV (1 second) were unable to stop the bleeding, which persisted over 15 minutes for all teeth. This may be due to the intense heat generated by CO2 laser, causing vasodilatation. Groups II and III displayed a similar appearance, but bleeding stopped in about 10 minutes. Group V (continuous mode) had no bleeding after irradiation, but a plasma-like liquid would come out for almost 2 minutes. When comparing to the control (Group VI), all the pulps would assume a jelly-like aspect, with black granulated tissue on the surface, covering totally the pulps of Group V and partially the other groups. The histological results will be discussed in a further study. From the data obtained, it seems that CO2 laser irradiation for pulpotomies should be done in a continuous mode, for clinical convenience in terms of time taken and effective irradiation.

  10. Aridity under conditions of increased CO2

    NASA Astrophysics Data System (ADS)

    Greve, Peter; Roderick, Micheal L.; Seneviratne, Sonia I.

    2016-04-01

    A string of recent of studies led to the wide-held assumption that aridity will increase under conditions of increasing atmospheric CO2 concentrations and associated global warming. Such results generally build upon analyses of changes in the 'aridity index' (the ratio of potential evaporation to precipitation) and can be described as a direct thermodynamic effect on atmospheric water demand due to increasing temperatures. However, there is widespread evidence that contradicts the 'warmer is more arid' interpretation, leading to the 'global aridity paradox' (Roderick et al. 2015, WRR). Here we provide a comprehensive assessment of modeled changes in a broad set of dryness metrics (primarily based on a range of measures of water availability) over a large range of realistic atmospheric CO2 concentrations. We use an ensemble of simulations from of state-of-the-art climate models to analyse both equilibrium climate experiments and transient historical simulations and future projections. Our results show that dryness is, under conditions of increasing atmospheric CO2 concentrations and related global warming, generally decreasing at global scales. At regional scales we do, however, identify areas that undergo changes towards drier conditions, located primarily in subtropical climate regions and the Amazon Basin. Nonetheless, the majority of regions, especially in tropical and mid- to northern high latitudes areas, display wetting conditions in a warming world. Our results contradict previous findings and highlight the need to comprehensively assess all aspects of changes in hydroclimatological conditions at the land surface. Roderick, M. L., P. Greve, and G. D. Farquhar (2015), On the assessment of aridity with changes in atmospheric CO2, Water Resour. Res., 51, 5450-5463

  11. Towards Overhauser DNP in supercritical CO2

    NASA Astrophysics Data System (ADS)

    van Meerten, S. G. J.; Tayler, M. C. D.; Kentgens, A. P. M.; van Bentum, P. J. M.

    2016-06-01

    Overhauser Dynamic Nuclear Polarization (ODNP) is a well known technique to improve NMR sensitivity in the liquid state, where the large polarization of an electron spin is transferred to a nucleus of interest by cross-relaxation. The efficiency of the Overhauser mechanism for dipolar interactions depends critically on fast local translational dynamics at the timescale of the inverse electron Larmor frequency. The maximum polarization enhancement that can be achieved for 1H at high magnetic fields benefits from a low viscosity solvent. In this paper we investigate the option to use supercritical CO2 as a solvent for Overhauser DNP. We have investigated the diffusion constants and longitudinal nuclear relaxation rates of toluene in high pressure CO2. The change in 1H T1 by addition of TEMPO radical was analyzed to determine the Overhauser cross-relaxation in such a mixture, and is compared with calculations based on the Force Free Hard Sphere (FFHS) model. By analyzing the relaxation data within this model we find translational correlation times in the range of 2-4 ps, depending on temperature, pressure and toluene concentration. Such short correlation times may be instrumental for future Overhauser DNP applications at high magnetic fields, as are commonly used in NMR. Preliminary DNP experiments have been performed at 3.4 T on high pressure superheated water and model systems such as toluene in high pressure CO2.

  12. Breadboard CO2 and humidity control system

    NASA Technical Reports Server (NTRS)

    Boehm, A. M.

    1976-01-01

    A regenerable CO2 and humidity control system is being developed for potential use on shuttle as an alternate to the baseline lithium hydroxide (LiOH)/condensing heat exchanger system. The system utilizes a sorbent material, designated HS-C, to adsorb CO2 and water vapor from the cabin atmosphere. The material is regenerated by exposing it to space vacuum. A half-size breadboard system, utilizing a flight representative HS-C canister, was designed, built, and performance tested to shuttle requirements for total CO2 and total humidity removal. The use of a new chemical matrix material allowed significant optimization of the system design by packing the HS-C chemical into the core of a heat exchanger which is manifolded to form two separate and distinct beds. Breadboard system performance was proven by parametric testing and simulated mission testing over the full range of shuttle crew sizes and metabolic loadings. Vacuum desorption testing demonstrated considerable savings in previously projected shuttle vacuum duct sizing.

  13. Towards Overhauser DNP in supercritical CO2.

    PubMed

    van Meerten, S G J; Tayler, M C D; Kentgens, A P M; van Bentum, P J M

    2016-06-01

    Overhauser Dynamic Nuclear Polarization (ODNP) is a well known technique to improve NMR sensitivity in the liquid state, where the large polarization of an electron spin is transferred to a nucleus of interest by cross-relaxation. The efficiency of the Overhauser mechanism for dipolar interactions depends critically on fast local translational dynamics at the timescale of the inverse electron Larmor frequency. The maximum polarization enhancement that can be achieved for (1)H at high magnetic fields benefits from a low viscosity solvent. In this paper we investigate the option to use supercritical CO2 as a solvent for Overhauser DNP. We have investigated the diffusion constants and longitudinal nuclear relaxation rates of toluene in high pressure CO2. The change in (1)H T1 by addition of TEMPO radical was analyzed to determine the Overhauser cross-relaxation in such a mixture, and is compared with calculations based on the Force Free Hard Sphere (FFHS) model. By analyzing the relaxation data within this model we find translational correlation times in the range of 2-4ps, depending on temperature, pressure and toluene concentration. Such short correlation times may be instrumental for future Overhauser DNP applications at high magnetic fields, as are commonly used in NMR. Preliminary DNP experiments have been performed at 3.4T on high pressure superheated water and model systems such as toluene in high pressure CO2. PMID:27082277

  14. 40 CFR 98.443 - Calculating CO2 geologic sequestration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Calculating CO2 geologic sequestration. You must calculate the mass of CO2 received using CO2 received... your approved MRV plan. (a) You must calculate and report the annual mass of CO2 received by pipeline...)(3) of this section, if applicable. (1) For a mass flow meter, you must calculate the total...

  15. 40 CFR 98.443 - Calculating CO2 geologic sequestration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Calculating CO2 geologic sequestration. You must calculate the mass of CO2 received using CO2 received... your approved MRV plan. (a) You must calculate and report the annual mass of CO2 received by pipeline...)(3) of this section, if applicable. (1) For a mass flow meter, you must calculate the total...

  16. Integration of the electrochemical depolorized CO2 concentrator with the Bosch CO2 reduction subsystem

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.; Wynveen, R. A.; Hallick, T. M.

    1976-01-01

    Regenerative processes for the revitalization of spacecraft atmospheres require an Oxygen Reclamation System (ORS) for the collection of carbon dioxide and water vapor and the recovery of oxygen from these metabolic products. Three life support subsystems uniquely qualified to form such an ORS are an Electrochemical CO2 Depolarized Concentrator (EDC), a CO2 Reduction Subsystem (BRS) and a Water Electrolysis Subsystem (WES). A program to develop and test the interface hardware and control concepts necessary for integrated operation of a four man capacity EDC with a four man capacity BRS was successfully completed. The control concept implemented proved successful in operating the EDC with the BRS for both constant CO2 loading as well as variable CO2 loading, based on a repetitive mission profile of the Space Station Prototype (SSP).

  17. Biosequestration of atmospheric CO2 and flue gas-containing CO2 by microalgae.

    PubMed

    Cheah, Wai Yan; Show, Pau Loke; Chang, Jo-Shu; Ling, Tau Chuan; Juan, Joon Ching

    2015-05-01

    The unceasing rise of greenhouse gas emission has led to global warming and climate change. Global concern on this phenomenon has put forward the microalgal-based CO2 sequestration aiming to sequester carbon back to the biosphere, ultimately reducing greenhouse effects. Microalgae have recently gained enormous attention worldwide, to be the valuable feedstock for renewable energy production, due to their high growth rates, high lipid productivities and the ability to sequester carbon. The photosynthetic process of microalgae uses atmospheric CO2 and CO2 from flue gases, to synthesize nutrients for their growth. In this review article, we will primarily discuss the efficiency of CO2 biosequestration by microalgae species, factors influencing microalgal biomass productions, microalgal cultivation systems, the potential and limitations of using flue gas for microalgal cultivation as well as the bio-refinery approach of microalgal biomass. PMID:25497054

  18. Impact of CO2 Impure stream on a CO2 Storage Reservoir

    NASA Astrophysics Data System (ADS)

    Segev, R.; Bear, J.; Bensabat, J.

    2013-12-01

    In a CO2 capture and storage (CCS) technology, a stream of CO2, extracted from the gas stream emitted from an industrial plant, is transported to a storage site where it is injected into a deep brine-containing geological reservoir for storage for very long time periods. The injected CO2 may contain various compositions of residual O2, SOx , NOx, and inert gases. In this work, we focus on the impact of the SO2 and its potential to acidify the reservoir brine. The amount of dissolved SO2 is determined by adjusting the Henry coefficient and fugacity coefficient for the mixture that contains CO2 as a major component and SO2. The models show the spreading of the pH level over time in the entire reservoir when different CO2-SO2 mixture compositions are injected. The minimum pH level achieved is 0.35 when 4% SO2 is injected, 1.8 when 2% SO2 is injected and 3.8 when a pure CO2 stream is injected. The model may serve as a tool to predict the influence of SO2 on the initial brine composition and on the initial rock properties. For example, a model result for the pH spreading in the reservoir, in the case of 2%SO2-CO2 injected mixture, is shown below. Fig.1. The pH level at the reservoir bedrock and caprock after 5 years for a 2%SO2-CO2 stream.

  19. TES/Aura L2 Carbon Dioxide (CO2) Lite Nadir (TL2CO2LN)

    Atmospheric Science Data Center

    2015-06-24

    TES/Aura L2 Carbon Dioxide (CO2) Lite Nadir (TL2CO2LN) News:  TES ... Level:  L2 Instrument:  TES/Aura L2 Carbon Dioxide Spatial Coverage:  5.3 km nadir ... OPeNDAP Access:  OPeNDAP Parameters:  Carbon Dioxide Order Data:  Reverb:   Order Data ...

  20. Process-dependent residual trapping of CO2 in sandstone

    NASA Astrophysics Data System (ADS)

    Zuo, Lin; Benson, Sally M.

    2014-04-01

    This paper demonstrates that the nature and extent of residual CO2 trapping depend on the process by which the CO2 phase is introduced into the rock. We compare residual trapping of CO2 in Berea Sandstone by imbibing water into a core containing either exsolved CO2 or CO2 introduced by drainage. X-ray computed tomography measurements are used to map the spatial distribution of CO2 preimbibition and postimbibition. Unlike during drainage where the CO2 distribution is strongly influenced by the heterogeneity of the rock, the distribution of exsolved CO2 is comparatively uniform. Postimbibition, the CO2 distribution retained the essential features for both the exsolved and drainage cases, but twice as much residual trapping is observed for exsolved CO2 even with similar preimbibition gas saturations. Residually trapped exsolved gas also disproportionately reduced water relative permeability. Development of process-dependent parameterization will help better manage subsurface flow processes and unlock benefits from gas exsolution.

  1. Uncertainty analyses of CO2 plume expansion subsequent to wellbore CO2 leakage into aquifers

    SciTech Connect

    Hou, Zhangshuan; Bacon, Diana H.; Engel, David W.; Lin, Guang; Fang, Yilin; Ren, Huiying; Fang, Zhufeng

    2014-08-01

    In this study, we apply an uncertainty quantification (UQ) framework to CO2 sequestration problems. In one scenario, we look at the risk of wellbore leakage of CO2 into a shallow unconfined aquifer in an urban area; in another scenario, we study the effects of reservoir heterogeneity on CO2 migration. We combine various sampling approaches (quasi-Monte Carlo, probabilistic collocation, and adaptive sampling) in order to reduce the number of forward calculations while trying to fully explore the input parameter space and quantify the input uncertainty. The CO2 migration is simulated using the PNNL-developed simulator STOMP-CO2e (the water-salt-CO2 module). For computationally demanding simulations with 3D heterogeneity fields, we combined the framework with a scalable version module, eSTOMP, as the forward modeling simulator. We built response curves and response surfaces of model outputs with respect to input parameters, to look at the individual and combined effects, and identify and rank the significance of the input parameters.

  2. Low pCO2 Air-Polarized CO2 Concentrator Development

    NASA Technical Reports Server (NTRS)

    Schubert, Franz H.

    1997-01-01

    Life Systems completed a Ground-based Space Station Experiment Development Study Program which verifies through testing the performance and applicability of the electrochemical Air-Polarized Carbon Dioxide Concentrator (APC) process technology for space missions requiring low (i.e., less than 3 mm Hg) CO2 partial pressure (pCO2) in the cabin atmosphere. Required test hardware was developed and testing was accomplished at an approximate one-person capacity CO2 removal level. Initially, two five-cell electrochemical modules using flight-like 0.5 sq ft cell hardware were tested individually, following by their testing at the integrated APC system level. Testing verified previously projected performance and established a database for sizing of APC systems. A four person capacity APC system was sized and compared with four candidate CO2 removal systems. At its weight of 252 lb, a volume of 7 cu ft and a power consumption of 566 W while operating at 2.2 mm Hg pCO2, the APC was surpassed only by an Electrochemical Depolarized CO2 Concentrator (EDC) (operating with H2), when compared on a total equivalent basis.

  3. CO2-Responsive Polymer-Functionalized Au Nanoparticles for CO2 Sensor.

    PubMed

    Ma, Ying; Promthaveepong, Kittithat; Li, Nan

    2016-08-16

    Metallic nanoparticles (NPs) coated with stimuli-responsive polymers (SRPs) exhibit tunable optical properties responding to external stimuli and show promising sensing applications. We present a new CO2-responsive polymer, poly(N-(3-amidino)-aniline) (PNAAN), coated gold NPs (AuNPs) synthesized by directly reducing HAuCl4 with a CO2-responsive monomer N-(3-amidino)-aniline (NAAN). The amidine group of PNAAN can be protonated into a hydrophilic amidinium group by dissolved CO2 (dCO2). This induces the PNAAN to swell and detach from the AuNP surface, resulting in AuNP aggregation and color change. By monitoring the UV absorbance change of AuNPs, a sensitive dCO2 sensor with a linear range of 0.0132 to 0.1584 hPa and a limit of detection (LOD) of 0.0024 hPa is developed. This method shows dramatic improvement in sensitivity and convenience of sample preparation compared with the previously reported dCO2 sensor. PMID:27459645

  4. CO2 Sequestration within Spent Oil Shale

    NASA Astrophysics Data System (ADS)

    Foster, H.; Worrall, F.; Gluyas, J.; Morgan, C.; Fraser, J.

    2013-12-01

    Worldwide deposits of oil shales are thought to represent ~3 trillion barrels of oil. Jordanian oil shale deposits are extensive and of high quality, and could represent 100 billion barrels of oil, leading to much interest and activity in the development of these deposits. The exploitation of oil shales has raised a number of environmental concerns including: land use, waste disposal, water consumption, and greenhouse gas emissions. The dry retorting of oil shales can overcome a number of the environmental impacts, but this leaves concerns over management of spent oil shale and CO2 production. In this study we propose that the spent oil shale can be used to sequester CO2 from the retorting process. Here we show that by conducting experiments using high pressure reaction facilities, we can achieve successful carbonation of spent oil shale. High pressure reactor facilities in the Department of Earth Sciences, Durham University, are capable of reacting solids with a range of fluids up to 15 MPa and 350°C, being specially designed for research with supercritical fluids. Jordanian spent oil shale was reacted with high pressure CO2 in order to assess whether there is potential for sequestration. Fresh and reacted materials were then examined by: Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Thermogravimetric Analysis (TGA), X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD) methods. Jordanian spent oil shale was found to sequester up to 5.8 wt % CO2, on reacting under supercritical conditions, which is 90% of the theoretical carbonation. Jordanian spent oil shale is composed of a large proportion of CaCO3, which on retorting decomposes, forming CaSO4 and Ca-oxides which are the focus of carbonation reactions. A factorially designed experiment was used to test different factors on the extent of carbonation, including: pressure; temperature; duration; and the water content. Analysis of Variance (ANOVA) techniques were then used to determine the significance of

  5. Effective Use of Natural CO2-RICH Systems for Stakeholder Communication: CO2FACTS.ORG

    NASA Astrophysics Data System (ADS)

    Olson, H. C.; Romanak, K.; Osborne, V.; Hovorka, S. D.; Clift, S.; Castner, A.

    2011-12-01

    The impact of using natural analogues as an avenue for communicating about CO2 injection and storage technology with stakeholders has been addressed by previous researchers, e.g., Romanak et al (2011), Dixon et al (2011). Analogies between natural CO2-rich systems and engineered CO2 storage are not necessarily straightforward, and stakeholder opinion is often based on factors other than technical accuracy of information (e.g., lack of trust, confidence, and fear). In order to enhance this communication pathway, STORE (Sequestration Training, Outreach, Research and Education), the outreach arm of the Gulf Coast Carbon Center at The University of Texas at Austin, has created an online resource (www.co2facts.org) to help stakeholders better understand the injection and storage of CO2 underground. The online resource includes frequently asked questions (FAQs) for a variety of CO2-storage-related issues, including those related to natural analogues, and uses examples of natural systems of CO2 release for communication. The content targets various levels of technical education and understanding. A unique feature of the online resource is its approach to verification of information. Each FAQ and example is "fact-checked" by an actual expert in the field. Part of this verification process is to provide an online link to background, credentials, scientific research and images of actual experts in the field at natural release sites. This approach helps put a face to, and potentially builds a relationship of trust with, the scientist behind the technical information. Videos of experts discussing natural systems and their similarities and differences with CO2 injection and storage sites are also part of the resource. Stakeholders commonly draw incorrect parallels between natural disasters that gain attention in the media (e.g., Lake Nyos) and CO2 injection and storage technology. The video images available at www.co2facts.org are a useful tool for assuaging environmental fears

  6. The Werkendam natural CO2 accumulation: An analogue for CO2 storage in depleted oil reservoirs

    NASA Astrophysics Data System (ADS)

    Bertier, Pieter; Busch, Andreas; Hangx, Suzanne; Kampman, Niko; Nover, Georg; Stanjek, Helge; Weniger, Philipp

    2015-04-01

    The Werkendam natural CO2 accumulation is hosted in the Röt (Early Triassic) sandstone of the West Netherlands Basin, at a depth of 2.8 km, about 20 km south-east of Rotterdam (NL). This reservoir, in a fault-bound structure, was oil-filled prior to charging with magmatic CO2 in the early Cretaceous. It therefore offers a unique opportunity to study long-term CO2-water-rock interactions in the presence of oil. This contribution will present the results of a detailed mineralogical and geochemical characterisation of core sections from the Werkendam CO2 reservoir and an adjacent, stratigraphically equivalent aquifer. X-ray diffraction combined with X-ray fluorescence spectrometry revealed that the reservoir samples contain substantially more feldspar and more barite and siderite than those from the aquifer, while the latter have higher hematite contents. These differences are attributed to the effects hydrocarbons and related fluids on diagenesis in the closed system of the CO2 reservoir versus the open-system of the aquifer. Petrophysical analyses yielded overall higher and more anisotropic permeability for the reservoir samples, while the porosity is overall not significantly different from that of their aquifer equivalents. The differences are most pronounced in coarse-grained sandstones. These have low anhydrite contents and contain traces of calcite, while all other analyzed samples contain abundant anhydrite, dolomite/ankerite and siderite, but no calcite. Detailed petrography revealed mm-sized zones of excessive primary porosity. These are attributed to CO2-induced dissolution of precompactional, grain-replacive anhydrite cement. Diagenetic dolomite/ankerite crystals are covered by anhedral, epitaxial ankerite, separated from the crystals by bitumen coats. Since these carbonates were oil-wet before CO2-charging, the overgrowths are interpreted to have grown after CO2-charging. Their anhedral habit suggests growth in a 2-phase water-CO2 system. Isotopic

  7. Method for tracing simulated CO2 leak in terrestrial environment with a 13CO2 tracer

    NASA Astrophysics Data System (ADS)

    Moni, Christophe; Rasse, Daniel

    2013-04-01

    Facilities for the geological storage of carbon dioxide (CO2) as part of carbon capture and storage (CCS) schemes will be designed to prevent any leakage from the defined 'storage complex'. However, developing regulations and guidance throughout the world (e.g. the EC Directive and the USEPA Vulnerability Evaluation Framework) recognize the importance of assessing the potential for environmental impacts from CO2 storage. RISCS, a European (FP7) project, aims to improve understanding of those impacts that could plausibly occur in the hypothetical case that unexpected leakage occurs. As part of the RISCS project the potential impacts that an unexpected CO2 leaks might have on a cropland ecosystems was investigated. A CO2 exposure field experiment based on CO2 injection at 85 cm depth under an oats culture was designed. To facilitate the characterization of the simulated leaking zone the gas used for injection was produced from natural gas and had a δ13C of -46‰. The aim of the present communication is to depict how the injected gas was traced within the soil-vegetation-atmosphere continuum using 13CO2 continuous cavity ring-down spectrometry (CRDS). Four subsurface experimental injection plots (6m x 3m) were set up. In order to test the effects of different intensity of leakage, the field experiment was designed as to create a longitudinal CO2 gradient for each plot. For this purpose gas supply pipes were inserted at one extremity of each plot at the base of a 45 cm thick layer of sand buried 40 cm below the surface under the clayey plough layer of Norwegian moraine soils. Soil CO2 concentration and isotopic signature were punctually recorded: 1) in the soil at 20 cm depth at 6 positions distributed on the central transect, 2) at the surface following a (50x50 cm) grid sampling pattern, and 3) in the canopy atmosphere at 10, 20, 30 cm along three longitudinal transects (seven sampling point per transect). Soil CO2 fluxes and isotopic signature were finally

  8. Saturated CO2 inhibits microbial processes in CO2-vented deep-sea sediments

    NASA Astrophysics Data System (ADS)

    de Beer, D.; Haeckel, M.; Neumann, J.; Wegener, G.; Inagaki, F.; Boetius, A.

    2013-08-01

    This study focused on biogeochemical processes and microbial activity in sediments of a natural deep-sea CO2 seepage area (Yonaguni Knoll IV hydrothermal system, Japan). The aim was to assess the influence of the geochemical conditions occurring in highly acidic and CO2 saturated sediments on sulfate reduction (SR) and anaerobic methane oxidation (AOM). Porewater chemistry was investigated from retrieved sediment cores and in situ by microsensor profiling. The sites sampled around a sediment-hosted hydrothermal CO2 vent were very heterogeneous in porewater chemistry, indicating a complex leakage pattern. Near the vents, droplets of liquid CO2 were observed emanating from the sediments, and the pH reached approximately 4.5 in a sediment depth > 6 cm, as determined in situ by microsensors. Methane and sulfate co-occurred in most sediment samples from the vicinity of the vents down to a depth of 3 m. However, SR and AOM were restricted to the upper 7-15 cm below seafloor, although neither temperature, low pH, nor the availability of methane and sulfate could be limiting microbial activity. We argue that the extremely high subsurface concentrations of dissolved CO2 (1000-1700 mM), which disrupt the cellular pH homeostasis, and lead to end-product inhibition. This limits life to the surface sediment horizons above the liquid CO2 phase, where less extreme conditions prevail. Our results may have to be taken into consideration in assessing the consequences of deep-sea CO2 sequestration on benthic element cycling and on the local ecosystem state.

  9. PLAINS CO2 REDUCTION (PCOR) PARTNERSHIP

    SciTech Connect

    Edward N. Steadman; Daniel J. Daly; Lynette L. de Silva; John A. Harju; Melanie D. Jensen; Erin M. O'Leary; Wesley D. Peck; Steven A. Smith; James A. Sorensen

    2006-01-01

    During the period of October 1, 2003, through September 30, 2005, the Plains CO2 Reduction (PCOR) Partnership, identified geologic and terrestrial candidates for near-term practical and environmentally sound carbon dioxide (CO2) sequestration demonstrations in the heartland of North America. The PCOR Partnership region covered nine states and three Canadian provinces. The validation test candidates were further vetted to ensure that they represented projects with (1) commercial potential and (2) a mix that would support future projects both dependent and independent of CO2 monetization. This report uses the findings contained in the PCOR Partnership's two dozen topical reports and half-dozen fact sheets as well as the capabilities of its geographic information system-based Decision Support System to provide a concise picture of the sequestration potential for both terrestrial and geologic sequestration in the PCOR Partnership region based on assessments of sources, sinks, regulations, deployment issues, transportation, and capture and separation. The report also includes concise action plans for deployment and public education and outreach as well as a brief overview of the structure, development, and capabilities of the PCOR Partnership. The PCOR Partnership is one of seven regional partnerships under Phase I of the U.S. Department of Energy National Energy Technology Laboratory's Regional Carbon Sequestration Partnership program. The PCOR Partnership, comprising 49 public and private sector members, is led by the Energy & Environmental Research Center at the University of North Dakota. The international PCOR Partnership region includes the Canadian provinces of Alberta, Saskatchewan, and Manitoba and the states of Montana (part), Wyoming (part), North Dakota, South Dakota, Nebraska, Missouri, Iowa, Minnesota, and Wisconsin.

  10. Anthropogenic CO2 emissions in Africa

    NASA Astrophysics Data System (ADS)

    Canadell, J. G.; Raupach, M. R.; Houghton, R. A.

    2008-11-01

    An understanding of the regional contributions and trends of anthropogenic carbon dioxide (CO2) emissions is critical to design mitigation strategies aimed at stabilizing atmospheric greenhouse gases. Here we report CO2 emissions from the combustion of fossil fuels and land use change in Africa for various time periods. Africa was responsible for an average of 500 TgC y-1 for the period 2000 2005. These emissions resulted from the combustion of fossil fuels (260 TgC y-1) and land use change (240 TgC y-1). Over this period, the African share of global emissions from land use change was 17%. For 2005, the last year reported in this study, African fossil fuel emissions were 285 TgC accounting for 3.7% of the global emissions. The 2000 2005 growth rate in African fossil fuel emissions was 3.2% y-1, very close to the global average. Fossil fuel emissions per capita in Africa are among the lowest in the world, at 0.32 tC y-1 compared to the global average of 1.2 tC y-1. The average amount of carbon (C) emitted as CO2 to produce 1 US of Gross Domestic Product (GDP) in Africa in 2005 was 187 gC/, close to the world average of 199 gC/. With the fastest population growth in the world and rising per capita GDP, Africa is likely to increase its share of global emissions over the coming decades although emissions from Africa will remain low compared to other continents.

  11. Anthropogenic CO2 emissions in Africa

    NASA Astrophysics Data System (ADS)

    Canadell, J. G.; Raupach, M. R.; Houghton, R. A.

    2009-03-01

    An understanding of the regional contributions and trends of anthropogenic carbon dioxide (CO2) emissions is critical to design mitigation strategies aimed at stabilizing atmospheric greenhouse gases. Here we report CO2 emissions from the combustion of fossil fuels and land use change in Africa for various time periods. Africa was responsible for an average of 500 Tg C y-1 for the period 2000-2005. These emissions resulted from the combustion of fossil fuels (260 Tg C y-1) and land use change (240 Tg C y-1). Over this period, the African share of global emissions from land use change was 17%. For 2005, the last year reported in this study, African fossil fuel emissions were 285 Tg C accounting for 3.7% of the global emissions. The 2000-2005 growth rate in African fossil fuel emissions was 3.2% y-1, very close to the global average. Fossil fuel emissions per capita in Africa are among the lowest in the world, at 0.32 t C y-1 compared to the global average of 1.2 t C y-1. The average amount of carbon (C) emitted as CO2 to produce 1 US{} of Gross Domestic Product (GDP) in Africa was 187 g C/ in 2005, close to the world average of 199 g C/. With the fastest population growth in the world and rising per capita GDP, Africa is likely to increase its share of global emissions over the coming decades although emissions from Africa will remain low compared to other continents.

  12. CO2 laser ranging systems study

    NASA Technical Reports Server (NTRS)

    Filippi, C. A.

    1975-01-01

    The conceptual design and error performance of a CO2 laser ranging system are analyzed. Ranging signal and subsystem processing alternatives are identified, and their comprehensive evaluation yields preferred candidate solutions which are analyzed to derive range and range rate error contributions. The performance results are presented in the form of extensive tables and figures which identify the ranging accuracy compromises as a function of the key system design parameters and subsystem performance indexes. The ranging errors obtained are noted to be within the high accuracy requirements of existing NASA/GSFC missions with a proper system design.

  13. [Laryngomalacia treated with CO2 laser].

    PubMed

    Larsen, Dalia Gustaityté; Berg, Jette Scheby; Illum, Peter

    2010-07-01

    Laryngomalacia is the most common laryngeal anomaly which causes inspiratory stridor in newborns. The disease is usually self-limiting and resolves before the age of two years. We present a case of severe laryngomalacia with feeding disorder and airway obstruction which needed surgical management--supraglottoplasty. The shortened aryepiglottic folds were incised using CO(2) laser and jet ventilation. The patient was observed at the hospital for one week after surgery and discharged. Four weeks after treatment, the patient was free of airway obstruction and feeding problems. PMID:20594541

  14. On Leakage from Geologic Storage Reservoirs of CO2

    SciTech Connect

    Pruess, Karsten

    2006-02-14

    Large amounts of CO2 would need to be injected underground to achieve a significant reduction of atmospheric emissions. The large areal extent expected for CO2 plumes makes it likely that caprock imperfections will be encountered, such as fault zones or fractures, which may allow some CO2 to escape from the primary storage reservoir. Leakage of CO2 could also occur along wellbores. Concerns with escape of CO2 from a primary geologic storage reservoir include (1) acidification of groundwater resources, (2) asphyxiation hazard when leaking CO2 is discharged at the land surface, (3) increase in atmospheric concentrations of CO2, and (4) damage from a high-energy, eruptive discharge (if such discharge is physically possible). In order to gain public acceptance for geologic storage as a viable technology for reducing atmospheric emissions of CO2, it is necessary to address these issues and demonstrate that CO2 can be injected and stored safely in geologic formations.

  15. The Field-Laboratory for CO2 Storage 'CO2SINK

    NASA Astrophysics Data System (ADS)

    Würdemann, Hilke; Möller, Fabian; Kühn, Michael; Borm, Günter; Schilling, Frank R.

    2010-05-01

    The first European onshore geological CO2 storage project in a saline aquifer CO2SINK is designed as a field size experiment to better understand in situ storage processes and to test various monitoring techniques. This EU project is run by 18 partners from universities, research institutes and industry out of 9 European countries (www.co2sink.org). The CO2 is injected into Upper Triassic sandstones (Stuttgart Formation) of a double-anticline at a depth of 650 m. The Stuttgart Formation represents a flu vial environment comprised of sandstone channels and silty to muddy deposits. The anticline forms a classical multibarrier system: The first caprock is a playa type mudstone of the Weser and Arnstadt formations directly overlying the Stuttgart formation. Laboratory tests revealed permeabilities in a µDarcy-range. The second main caprock is a tertiary clay, the so-called Rupelton. To determine the maximum injection pressure modified leak-off tests (without fracturing the caprock) were performed resulting in values around 120 bar. Due to safety standards the pressure threshold is set to 82 bar until more experience on the reservoir behaviour is available. The sealing property of the secondary cap rock is well known from decades of natural gas storage operations at the testing site and was the basis for the permission to operate the CO2 storage by the mining authority. Undisturbed, initial reservoir conditions are 35 °C and 62 bar. The initial reservoir fluid is highly saline with about 235 g/l total dissolved solids primarily composed of sodium chloride with notable amounts of calcium chloride. The initial pH value is 6.6. Hydraulic tests as well as laboratory tests revealed a permeability between 50 and 100 mDarcy for the sand channels of the storage formation. Within twenty months of storage operation, about 30,000 t of CO2 have been injected. Spreading of the CO2 plume is monitored by a broad range of geophysical techniques. The injection well and the two

  16. Wheat response to CO2 enrichment: CO2 exchanges transpiration and mineral uptakes

    NASA Technical Reports Server (NTRS)

    Andre, M.; Ducloux, H.; Richaud, C.

    1986-01-01

    When simulating canopies planted in varied densities, researchers were able to demonstrate that increase of dry matter production by enhancing CO2 quickly becomes independant of increase of leaf area, especially above leaf area index of 2; dry matter gain results mainly from photosynthesis stimulation per unit of surface (primary CO2 effect). When crop density is low (the plants remaining alone a longer time), the effects of increasing leaf surface (tillering, leaf elongation here, branching for other plants etc.) was noticeable and dry matter simulation factor reached 1.65. This area effect decreased when canopy was closed in, as the effect of different surfaces no longer worked. The stimulation of photosynthesis reached to the primary CO2 effect. The accumulation in dry matter which was fast during that phase made the original weight advantage more and more neglectible. Comparison with short term measurements showed that first order long term effect of CO2 in wheat is predictible with short term experiment, from the effect of CO2 on photosynthesis measured on reference sample.

  17. Public Acceptance for Geological CO2-Storage

    NASA Astrophysics Data System (ADS)

    Schilling, F.; Ossing, F.; Würdemann, H.; Co2SINK Team

    2009-04-01

    Public acceptance is one of the fundamental prerequisites for geological CO2 storage. In highly populated areas like central Europe, especially in the vicinity of metropolitan areas like Berlin, underground operations are in the focus of the people living next to the site, the media, and politics. To gain acceptance, all these groups - the people in the neighbourhood, journalists, and authorities - need to be confident of the security of the planned storage operation as well as the long term security of storage. A very important point is to show that the technical risks of CO2 storage can be managed with the help of a proper short and long term monitoring concept, as well as appropriate mitigation technologies e.g adequate abandonment procedures for leaking wells. To better explain the possible risks examples for leakage scenarios help the public to assess and to accept the technical risks of CO2 storage. At Ketzin we tried the following approach that can be summed up on the basis: Always tell the truth! This might be self-evident but it has to be stressed that credibility is of vital importance. Suspiciousness and distrust are best friends of fear. Undefined fear seems to be the major risk in public acceptance of geological CO2-storage. Misinformation and missing communication further enhance the denial of geological CO2 storage. When we started to plan and establish the Ketzin storage site, we ensured a forward directed communication. Offensive information activities, an information centre on site, active media politics and open information about the activities taking place are basics. Some of the measures were: - information of the competent authorities through meetings (mayor, governmental authorities) - information of the local public, e.g. hearings (while also inviting local, regional and nation wide media) - we always treated the local people and press first! - organizing of bigger events to inform the public on site, e.g. start of drilling activities (open

  18. CO2 exchange in Thuringia, Germany

    NASA Astrophysics Data System (ADS)

    Anthoni, P. M.; Knohl, A.; Freibauer, A.; Ziegler, W.; Kolle, O.; Schulze, E.-D.

    2003-04-01

    Eddy covariance technique is used to measure the net CO_2 exchange (NEE) over forest and agricultural areas in Thuringia, Germany. Measurements are performed at a managed and unmanaged Beech stand, a managed Spruce stand and an agricultural field with Winter Wheat in 2001 and Potato in 2002. Large contrasts were found in NEE rates between the ecosystems. Though managed and unmanaged Beech had very similar NEE rates, main differences between those two sites arose because of an earlier leaf emergence at the managed beech site. Spruce had higher NEE in spring but substantially lower NEE in summer than the Beech stands. Overall resulting in a substantially lower annual NEE, which is mainly attributable to an almost two times higher ecosystem respiration, despite lower ecosystem temperatures at the Spruce site. Crops had high NEE uptake rates, but growing season length is short compared to the forest ecosystems. Therefore agricultural land had moderate annual NEE uptake rates (1--2tC ha-1), but when harvest is taken into account the agricultural ecosystems are a source for CO_2 (1--3tC ha-1). Forests cover about 30% of the area in Thuringia, 50% is agriculture, and 20% grassland and other land-use types. Agriculture seems to loose carbon and forest gain carbon, indicating that Thuringia would probably be a carbon source, or not be statistically different from being carbon neutral.

  19. CO2 Laser Absorption in Ablation Plasmas

    SciTech Connect

    Eckel, Hans-Albert; Tegel, Jochen; Schall, Wolfgang O.

    2006-05-02

    The impulse formation by laser ablation is limited by the premature absorption of the incident laser radiation in the initially produced cloud of ablation products. The power fraction of a CO2 laser pulse transmitted through a small hole in a POM sample for pulse energies of 35 to 150 J focused on a spot of 2 cm2 has been compared with the incident power. The plasma formation in vacuum and in air of 3500 Pa and the spread of the shock wave with velocities of 1.6 to 2.4 km/s in the low pressure air was observed by Schlieren photography. A sharp edged dark zone with a maximum extension of 10 to 12 mm away from the target surface develops within 5 {mu}s independently of the pressure and is assumed to be a plasma. In order to find out, if this is also the zone where the majority of the incident laser radiation is absorbed, a CO2 probe laser beam was directed through the expansion cloud parallel to and at various distances from the sample surface. The time behavior of the absorption signal of the probe beam has been measured and an absorption wave could be observed.

  20. Uncertainty in gridded CO2 emissions estimates

    NASA Astrophysics Data System (ADS)

    Hogue, Susannah; Marland, Eric; Andres, Robert J.; Marland, Gregg; Woodard, Dawn

    2016-05-01

    We are interested in the spatial distribution of fossil-fuel-related emissions of CO2 for both geochemical and geopolitical reasons, but it is important to understand the uncertainty that exists in spatially explicit emissions estimates. Working from one of the widely used gridded data sets of CO2 emissions, we examine the elements of uncertainty, focusing on gridded data for the United States at the scale of 1° latitude by 1° longitude. Uncertainty is introduced in the magnitude of total United States emissions, the magnitude and location of large point sources, the magnitude and distribution of non-point sources, and from the use of proxy data to characterize emissions. For the United States, we develop estimates of the contribution of each component of uncertainty. At 1° resolution, in most grid cells, the largest contribution to uncertainty comes from how well the distribution of the proxy (in this case population density) represents the distribution of emissions. In other grid cells, the magnitude and location of large point sources make the major contribution to uncertainty. Uncertainty in population density can be important where a large gradient in population density occurs near a grid cell boundary. Uncertainty is strongly scale-dependent with uncertainty increasing as grid size decreases. Uncertainty for our data set with 1° grid cells for the United States is typically on the order of ±150%, but this is perhaps not excessive in a data set where emissions per grid cell vary over 8 orders of magnitude.

  1. Factors affecting the direct mineralization of CO2 with olivine.

    PubMed

    Kwon, Soonchul; Fan, Maohong; DaCosta, Herbert F M; Russell, Armistead G

    2011-01-01

    Olivine, one of the most abundant minerals existing in nature, is explored as a CO2 carbonation agent for direct carbonation of CO2 in flue gas. Olivine based CO2 capture is thermodynamically favorable and can form a stable carbonate for long-term storage. Experimental results have shown that water vapor plays an important role in improving CO2 carbonation rate and capacities. Other operation conditions including reaction temperature, initial CO2 concentration, residence time corresponding to the flow rate of CO2 gas stream, and water vapor concentration also considerably affect the performance of the technology. PMID:22128528

  2. Estimation of continuous anthropogenic CO2: model-based evaluation of CO2, CO, δ13C(CO2) and Δ14C(CO2) tracer methods

    NASA Astrophysics Data System (ADS)

    Vardag, S. N.; Gerbig, C.; Janssens-Maenhout, G.; Levin, I.

    2015-11-01

    We investigate different methods for estimating anthropogenic CO2 using modeled continuous atmospheric concentrations of CO2 alone, as well as CO2 in combination with the surrogate tracers CO, δ13C(CO2) and Δ14C(CO2). These methods are applied at three hypothetical stations representing rural, urban and polluted conditions. We find that, independent of the tracer used, an observation-based estimate of continuous anthropogenic CO2 is not yet feasible at rural measurement sites due to the low signal-to-noise ratio of anthropogenic CO2 estimates at such settings. The tracers δ13C(CO2) and CO provide an accurate possibility to determine anthropogenic CO2 continuously, only if all CO2 sources in the catchment area are well characterized or calibrated with respect to their isotopic signature and CO to anthropogenic CO2 ratio. We test different calibration strategies for the mean isotopic signature and CO to CO2 ratio using precise Δ14C(CO2) measurements on monthly integrated as well as on grab samples. For δ13C(CO2), a calibration with annually averaged 14C(CO2) grab samples is most promising, since integrated sampling introduces large biases into anthropogenic CO2 estimates. For CO, these biases are smaller. The precision of continuous anthropogenic CO2 determination using δ13C(CO2) depends on measurement precision of δ13C(CO2) and CO2, while the CO method is mainly limited by the variation in natural CO sources and sinks. At present, continuous anthropogenic CO2 could be determined using the tracers δ13C(CO2) and/or CO with a precision of about 30 %, a mean bias of about 10 % and without significant diurnal discrepancies. Hypothetical future measurements of continuous Δ14C(CO2) with a precision of 5 ‰ are promising for anthropogenic CO2 determination (precision ca. 10-20 %) but are not yet available. The investigated tracer-based approaches open the door to improving, validating and reducing biases of highly resolved emission inventories using atmospheric

  3. Carbon Dioxide Exchanges in Leaves. I. Discrimination Between 14CO2 and 12CO2 in Photosynthesis 1

    PubMed Central

    Yemm, E. W.; Bidwell, R. G. S.

    1969-01-01

    In order to measure CO2 exchange reactions by leaves using isotopes of CO2, it is necessary to know precisely the discrimination against 14CO2 by leaves. Earlier determinations of discrimination are at variance, and may be inaccurate because of assumptions made about the rate of photorespiration. Maize leaves evolve little or no CO2 in light, and so provide suitable material for this measurement. Discrimination against 14CO2 in photosynthesis by maize leaves is almost precisely the same as in CO2 absorption by NaOH solution, amounting to 2.1 and 2.0% respectively. The agreement between these values and their close approximation to the relative rates of diffusion of 12CO2 and 14CO2, calculated from Graham's law, shows that diffusion into the leaf is primarily responsible for discrimination against 14CO2 in photosynthesis. PMID:16657206

  4. Interface characteristics in Co2MnSi/Ag/Co2MnSi trilayer

    NASA Astrophysics Data System (ADS)

    Li, Yang; Chen, Hong; Wang, Guangzhao; Yuan, Hongkuan

    2016-05-01

    Interface characteristics of Co2MnSi/Ag/Co2MnSi trilayer have been investigated by means of first-principles. The most likely interface is formed by connecting MnSi-termination to the bridge site between two Ag atoms. As annealed at high temperature, the formation of interface DO3 disorder is most energetically favorable. The spin polarization is reduced by both the interface itself and interface disorder due to the interface state occurs in the minority-spin gap. As a result, the magneto-resistance ratio has a sharp drop based on the estimation of a simplified modeling.

  5. The spectroscopic foundation of CO2 climate forcing

    NASA Astrophysics Data System (ADS)

    Mlynczak, M. G.; Daniels, T.; Kratz, D. P.; Collins, W.; Feldman, D.; Lawler, J. E.; Anderson, L. W.; Fahey, D. W.; Hunt, L. A.

    2015-12-01

    The radiative forcing (RF) of carbon dioxide (CO2) is the leading contribution to climate change from anthropogenic activities. Calculating CO2 RF requires detailed knowledge of spectral line parameters and lineshape functions for thousands of infrared absorption lines. A reliable spectroscopic characterization of CO2 forcing is therefore a critical input to scientific and policy-oriented assessments of present climate and future climate change. Our study is partly motivated by a recent assertion that CO2 RF values, and hence predictions of climate sensitivity to elevated CO2, have a significant high bias because the CO2 spectroscopic parameters being used are incorrect. Our results show that CO2 RF in a variety of atmospheres is remarkably insensitive to known uncertainties in the three main CO2 spectroscopic parameters: the line strengths, half widths, and line shapes. We demonstrate that this is due largely to the definition of CO2 RF, which is the difference between the CO2 longwave net flux at the tropopause for doubled CO2 concentrations from the preindustrial era. We also assess the effects of sub-Lorentzian wings of CO2 lines and find that the computed RF is largely insensitive to the spectral lineshape function. Overall, the spectroscopic uncertainty in present-day CO2 RF is less than a few percent. Our study highlights the basics and subtleties of RF calculations, addressing interests of the expert and non-expert.

  6. Geophysical Implications of Enceladus' CO2 Frost

    NASA Astrophysics Data System (ADS)

    Matson, D.; Davies, A. G.; Johnson, T. V.; Castillo, J. C.; Lunine, J. I.

    2013-12-01

    CO2 frost has been reported on the surface of Enceladus [1]. We suggest that the frost originated from shallow gas pockets below the surface. These pockets are a natural consequence of the ocean water circulation hypothesis [2]. They are different from the plume chambers [3] and would constitute a previously unrecognized structure in the surface. The oceanic circulation uses gas bubbles to make seawater buoyant and bring up water, chemicals, and heat from a warm ocean at depth [2]. The ocean water rises through the icy crust and near the surface it spreads out laterally beneath a relatively thin ice cap, following the pattern indicated by the thermal anomalies identified in Cassini data [4,5]. Topography on the bottom of this cap ice is conducive to the formation of gas pockets. As the ocean water flows horizontally, the gas bubbles in it continue to rise vertically. Even though their vertical migration may be slow and even if the flow is relatively turbulent, some bubbles reach recesses in the bottom of the ice cap and, over time, pop and form gas pockets. The gas pockets are envisioned as being ruptured by the regular fissuring of ice in the South Polar Region. Hurford et al. [6] have modelled the tidally controlled openings of rifts in the SPR. If one of these rifts reaches a gas pocket, CO2 gas may come to the surface. The tortuosity and other properties of its route will determine if it vents as a seep or a jet. If enough gas is vented and the molecules in the transient cloud have many collisions, some of them will be scattered to the surface and freeze. It was noted by Brown, et al. [1] that the frost deposits may not be permanent and that an active replenishment processes might be necessary. Studies of CO2 frost on Iapetus suggest that migration can be significant [7]. This work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. al., Science 311, 1425-1428, 2006. [2] Matson D. L. et al., Icarus 221, 53

  7. Experimental Investigations into CO2 Interactions with Injection Well Infrastructure for CO2 Storage

    NASA Astrophysics Data System (ADS)

    Syed, Amer; Shi, Ji-Quan; Durucan, Sevket; Nash, Graham; Korre, Anna

    2013-04-01

    Wellbore integrity is an essential requirement to ensure the success of a CO2 Storage project as leakage of CO2 from the injection or any other abandoned well in the storage complex, could not only severely impede the efficiency of CO2 injection and storage but also may result in potential adverse impact on the surrounding environment. Early research has revealed that in case of improper well completions and/or significant changes in operating bottomhole pressure and temperature could lead to the creation of microannulus at cement-casing interface which may constitute a preferential pathway for potential CO2 leakage during and post injection period. As a part of a European Commission funded CO2CARE project, the current research investigates the sealing behaviour of such microannulus at the cement-casing interface under simulated subsurface reservoir pressure and temperature conditions and uses the findings to develop a methodology to assess the overall integrity of CO2 storage. A full scale wellbore experimental test set up was constructed for use under elevated pressure and temperature conditions as encountered in typical CO2 storage sites. The wellbore cell consists of an assembly of concentric elements of full scale casing (Diameter= 0.1524m), cement sheath and an outer casing. The stainless steel outer ring is intended to simulate the stiffness offered by the reservoir rock to the displacement applied at the wellbore. The Central Loading Mechanism (CLM) consists of four case hardened shoes that can impart radial load onto the well casing. The radial movement of the shoes is powered through the synchronised movement of four precision jacks controlled hydraulically which could impart radial pressures up to 15 MPa. The cell body is a gas tight enclosure that houses the wellbore and the central loading mechanism. The setup is enclosed in a laboratory oven which acts both as temperature and safety enclosure. Prior to a test, cement mix is set between the casing and

  8. Framework for Assessing Biogenic CO2 Emissions from Stationary Sources

    EPA Science Inventory

    This revision of the 2011 report, Accounting Framework for Biogenic CO2 Emissions from Stationary Sources, evaluates biogenic CO2 emissions from stationary sources, including a detailed study of the scientific and technical issues associated with assessing biogenic carbon dioxide...

  9. Enhanced Molecular Sieve CO2 Removal Evaluation

    NASA Technical Reports Server (NTRS)

    Rose, Susan; ElSherif, Dina; MacKnight, Allen

    1996-01-01

    The objective of this research is to quantitatively characterize the performance of two major types of molecular sieves for two-bed regenerative carbon dioxide removal at the conditions compatible with both a spacesuit and station application. One sorbent is a zeolite-based molecular sieve that has been substantially improved over the materials used in Skylab. The second sorbent is a recently developed carbon-based molecular sieve. Both molecular sieves offer the potential of high payoff for future manned missions by reducing system complexity, weight (including consumables), and power consumption in comparison with competing concepts. The research reported here provides the technical data required to improve CO2 removal systems for regenerative life support systems for future IVA and EVA missions.

  10. CO2 laser therapy of rhinophyma

    NASA Astrophysics Data System (ADS)

    Voigt, Peggy; Jovanovic, Sergije; Sedlmaier, Benedikt W.

    2000-06-01

    Laser treatment of skin changes has become common practice in recent years. High absorption of the CO2 laser wavelength in water is responsible for its low penetration dpt in biological tissue. Shortening the tissue exposure time minimizes thermic side effects of laser radiation such as carbonization and coagulation. This can be achieved with scanner systems that move the focused laser beam over a defined area by microprocessor-controlled rapidly rotating mirrors. This enables controlled and reliable removal of certain dermal lesions, particularly hypertrophic scars, scars after common acne, wrinkles and rhinophyma. Laser ablation of rhinophyma is a stress-minimizing procedure for the surgeon and the patient, since it is nearly bloodless and can be performed under local anaesthesia. Cosmetically favorable reepithelization of the lasered surfaces is achieved within a very short period of time.

  11. Spaceborne CO2 laser communications systems

    NASA Technical Reports Server (NTRS)

    Mcelroy, J. H.; Mcavoy, N.; Johnson, E. H.; Goodwin, F. E.; Peyton, B. J.

    1975-01-01

    Projections of the growth of earth-sensing systems for the latter half of the 1980's show a data transmission requirement of 300 Mbps and above. Mission constraints and objectives lead to the conclusion that the most efficient technique to return the data from the sensing satellite to a ground station is through a geosynchronous data relay satellite. Of the two links that are involved (sensing satellite to relay satellite and relay satellite to ground), a laser system is most attractive for the space-to-space link. The development of CO2 laser systems for space-to-space applications is discussed with the completion of a 300 Mpbs data relay receiver and its modification into a transceiver. The technology and state-of-the-art of such systems are described in detail.

  12. Atmospheric effects on CO2 laser propagation

    NASA Technical Reports Server (NTRS)

    Murty, S. S. R.; Bilbro, J. W.

    1978-01-01

    An investigation was made of the losses encountered in the propagation of CO2 laser radiation through the atmosphere, particularly as it applies to the NASA/Marshall Space Flight Center Pulsed Laser Doppler System. As such it addresses three major areas associated with signal loss: molecular absorption, refractive index changes in a turbulent environment, and aerosol absorption and scattering. In particular, the molecular absorption coefficients of carbon dioxide, water vapor, and nitrous oxide are calculated for various laser lines in the region of 10.6 mu m as a function of various pressures and temperatures. The current status in the physics of low-energy laser propagation through a turbulent atmosphere is presented together with the analysis and evaluation of the associated heterodyne signal power loss. Finally, aerosol backscatter and extinction coefficients are calculated for various aerosol distributions and the results incorporated into the signal-to-noise ratio equation for the Marshall Space Flight Center system.

  13. Bosch CO2 Reduction System Development

    NASA Technical Reports Server (NTRS)

    Holmes, R. F.; King, C. D.; Keller, E. E.

    1975-01-01

    Refinements in the design of a Bosch CO2 reduction unit for spacecraft O2 production are described. Sealing of the vacuum insulation jacket was simplified so that high vacuum and high insulation performance are easily maintained. The device includes a relatively simple concentric shell recuperative heat exchanger which operates at approximately 95% temperature effectiveness and helps lower power consumption. The influence of reactor temperature, pressure, and recycle gas composition on power consumption was investigated. In general, precise control is not required since power consumption is not very sensitive to moderate variations of these parameters near their optimum values. There are two process rate control modes which match flow rate to process demand. Catalyst conditioning, support, and packing pattern developments assure consistent starts, reduced energy consumption, and extended cartridge life. Operation levels for four or five men were maintained with overall power input values of 50 to 60 watts per man.

  14. CO2 Sequestration and Recycle by Photosynthesis

    SciTech Connect

    Steven S.C. Chuang

    2004-02-01

    Visible light-photocatalysis could provide a cost-effective route to recycle CO2 to useful chemicals or fuels. Research is planned to study the reactivity of adsorbates, their role in the photosynthesis reaction, and their relation to the nature of surface sites during photosynthesis of methanol and hydrocarbons from CO{sub 2}/H{sub 2}O. The year two research focus catalyst screening and IR studies. Key research results show Pd/TiO2 exhibits the highest activity for hydrocarbon synthesis from photocatalytic reactions. The in situ IR could successfully monitor the adsorbate hydrocarbon species on Cu/TiO2. Year III research will focus on developing a better understanding of the key factors which control the catalyst activity.

  15. Anterior capsulotomy using the CO2 laser

    NASA Astrophysics Data System (ADS)

    Barak, Adiel; Ma-Naim, Tova; Rosner, Mordechai; Eyal, Ophir; Belkin, Michael

    1998-06-01

    Continuous circular capsulorhexis (CCC) is the preferred technique for removal of the anterior capsule during cataract surgery due to this technique assuring accurate centration of the intraocular lens. During modern cataract surgery, especially with small or foldable intra ocular lenses, centration of the lens is obligatory. Radial tears at the margin of an anterior capsulotomy may be associated with the exit of at least one loop of an intraocular lens out of the capsular bag ('pea pod' effect) and its subsequent decentration. The anterior capsule is more likely to ream intact if the continuous circular capsulorhexis (CCC) technique is used. Although manual capsulorhexis is an ideal anterior capsulectomy technique for adults, many ophthalmologists are still uncomfortable with it and find it difficult to perform, especially in complicated cases such as these done behind small pupil, cataract extraction in children and pseudoexfoliation syndrome. We have developed a technique using a CO2 laser system for safe anterior capsulotomy and tested it in animal eyes.

  16. Nominal hazard distances for CO2 lasers

    NASA Astrophysics Data System (ADS)

    Folkes, J. A.; Tyrer, J.; Bandle, A. M.

    Several values of nominal hazard distances (NHD's) for CO2 lasers are reported for different industrial laser systems. For the same laser system the NHD is increased in welding as opposed to cutting applications because a longer focal length lens is used. In most systems the NHD decreases with decreasing laser power because the beam diameter remains approximately the same for a given laser. If the same series of lasers are compared, each with increasing maximum power output, the NHD generally increases, nonlinearly with increasing power. However, in the 1.5 kW and 3 kW region the hazard distance may decrease with increasing power. This decrease is attributed to the increase in laser beam diameter arising from the transition between TEM00 and a TEM01 mode at this point.

  17. CO2 laser milling of hard tissue

    NASA Astrophysics Data System (ADS)

    Werner, Martin; Ivanenko, Mikhail; Harbecke, Daniela; Klasing, Manfred; Steigerwald, Hendrik; Hering, Peter

    2007-02-01

    Drilling of bone and tooth tissue belongs to recurrent medical procedures (screw- and pin-bores, bores for implant inserting, trepanation etc.). Small round bores can be in general quickly produced with mechanical drills. Problems arise however by angled drilling, by the necessity to fulfill the drilling without damaging of sensitive soft tissue beneath the bone, or by the attempt to mill precisely noncircular small cavities. We present investigations on laser hard tissue "milling", which can be advantageous for solving these problems. The "milling" is done with a CO2 laser (10.6 μm) with pulse duration of 50 - 100 μs, combined with a PC-controlled galvanic beam scanner and with a fine water-spray, which helps to avoid thermal side-effects. The damaging of underlying soft tissue can be prevented through control of the optical or acoustical ablation signal. The ablation of hard tissue is accompanied with a strong glowing, which is absent during the laser beam action on soft tissue. The acoustic signals from the diverse tissue types exhibit distinct differences in the spectral composition. Also computer image analysis could be a useful tool to control the operation. Laser "milling" of noncircular cavities with 1 - 4 mm width and about 10 mm depth is particularly interesting for dental implantology. In ex-vivo investigations we found conditions for fast laser "milling" of the cavities without thermal damage and with minimal tapering. It included exploration of different filling patterns (concentric rings, crosshatch, parallel lines and their combinations), definition of maximal pulse duration, repetition rate and laser power, optimal position of the spray. The optimized results give evidences for the applicability of the CO2 laser for biologically tolerable "milling" of deep cavities in the hard tissue.

  18. Atmospheric measurement of point source fossil fuel CO2 emissions

    NASA Astrophysics Data System (ADS)

    Turnbull, J. C.; Keller, E. D.; Baisden, W. T.; Brailsford, G.; Bromley, T.; Norris, M.; Zondervan, A.

    2013-11-01

    We use the Kapuni Gas Treatment Plant to examine methodologies for atmospheric monitoring of point source fossil fuel CO2 (CO2ff) emissions. The Kapuni plant, located in rural New Zealand, removes CO2 from locally extracted natural gas and vents that CO2 to the atmosphere, at a rate of ~0.1 Tg carbon per year. The plant is located in a rural dairy farming area, with no other significant CO2ff sources nearby, but large, diurnally varying, biospheric CO2 fluxes from the surrounding highly productive agricultural grassland. We made flask measurements of CO2 and 14CO2 (from which we derive the CO2ff component) and in situ measurements of CO2 downwind of the Kapuni plant, using a Helikite to sample transects across the emission plume from the surface up to 100 m a.g.l. We also determined the surface CO2ff content averaged over several weeks from the 14CO2 content of grass samples collected from the surrounding area. We use the WindTrax plume dispersion model to compare the atmospheric observations with the emissions reported by the Kapuni plant, and to determine how well atmospheric measurements can constrain the emissions. The model has difficulty accurately capturing the fluctuations and short-term variability in the Helikite samples, but does quite well in representing the observed CO2ff in 15 min averaged surface flask samples and in ~1 week integrated CO2ff averages from grass samples. In this pilot study, we found that using grass samples, the modeled and observed CO2ff emissions averaged over one week agreed to within 30%. The results imply that greater verification accuracy may be achieved by including more detailed meteorological observations and refining 14CO2 sampling strategies.

  19. Assessment of CO2 flux measurements in different soil types

    NASA Astrophysics Data System (ADS)

    Xia, L.; Szlavecz, K.; Musaloiu, R.; Cupchup, J.; Pitz, S.

    2008-12-01

    Accurate measurements of soil CO2 efflux are extraordinarily challenging due to the very properties of CO2 transport in a porous medium of soil. The most commonly used method today is the chamber method, which provides direct measurements of CO2 efflux at the soil surface, but it can not measure the soil CO2 flux continuously. In order to develop new measurement methods in soil CO2 efflux, small solid-state CO2 sensors have been used to continuously to monitor soil CO2 profiles by burying these sensors at different soil depths. Using this method we compared soil CO2 efflux of four different soil types: forests soil, grassland soil (collected in Maryland) commercial potting soil and pure sand as control. CO2 concentration varied between 500 ppm in sand and 8000 ppm in forest soil at depth 12 cm. CO2 flux had the following order: Forest (0.3~0.4 mg CO2 m-2 s-1), potting soil (0.1~0.14 mg CO2 m-2 s-1 ), grassland (0.03~0.05 mg CO2 m-2 s-1), sand ( 0 mg CO2 m-2 s-1 ). Exponential relationship between temperature and CO2 flux was established for forest soil and potting soil only. Leaf litter, often thick layer in many terrestrial ecosystems and a significant source of CO2 production, is not part of the of the diffusivity models. We are currently conducting experiments which include the effect of leaf litter and soil invertebrates into soil respiration.

  20. SOLUBILITY OF ORGANIC BIOCIDES IN SUPERCRITICAL CO2 AND CO2+ COSOLVENT MIXTURES

    EPA Science Inventory

    Solubilities of four organic biocides in supercritical carbon dioxide (Sc-CO2) were measured using a dynamic flowr apparatus over a pressure range of 10 to 30 MPa and temperature of 35-80 degrees C. The biocides studied were: Amical-48 (diiodomethyl p-tolyl sulfone), chlorothalo...

  1. Optical properties of CO2 ice and CO2 snow in the ultraviolet, visible, and infrared

    NASA Technical Reports Server (NTRS)

    Warren, Stephen

    1993-01-01

    The project was to measure the optical constants of CO2 ice in the spectral regions of weak absorption. Many previous measurements had been made by others in the strong absorption bands, but the weak regions had been poorly measured or not measured at all. In these regions the emissivity of CO2 frost and CO2 clouds is quite sensitive to particle sizes and to the value of the absorption coefficient, so the new measurements will have applications to energy budget and remote sensing of the Martian surface and atmosphere. During the time period covered by this grant, a method was developed for growing clear crystals of CO2, 4 cm in length. An apparatus was constructed for accurate measurement of spectral transmission through these crystals, for wavelengths 0.18-3.8 micrometers, covering the near-ultraviolet, visible, and near-infrared regions, bounded by the strong ultraviolet absorption and the 4.3-micrometer band. Our new best estimate of the spectral absorption coefficient (expressed as imaginary refractive index) is shown. It is a composite result of many measurements on dozens of crystals. Now that we have a good dataset for the shortwave absorption spectrum, the focus of the research has moved to the thermal infrared, for which a Fourier Transform interferometer has been adapted for use with C02-ice crystals.

  2. Industrial CO2 Removal: CO2 Capture from Ambient Air and Geological Sequestration

    SciTech Connect

    Dooley, James J.

    2011-06-08

    This abstract and its accompanying presentation will provide an overview of two distinct industrial processes for removing carbon dioxide (CO2) from the atmosphere as a means of addressing anthropogenic climate change. The first of these is carbon dioxide capture and storage (CCS) coupled with large scale biomass production (hereafter referred to as bioCCS). The second is CO2 capture from ambient air via industrial systems (hereafter referred to as direct air capture (DAC)). In both systems, the captured CO2 would be injected into deep geologic formations so as to isolate it from the atmosphere. The technical literature is clear that both of these technologies are technically feasible as of today (IPCC, 2005; Keith, 2009; Lackner, 2009; Luckow et al., 2010; Ranjan and Herzog, 2011). What is uncertain is the relative cost of these industrial ambient-air CO2 removal systems when compared to other emissions mitigation measures, the ultimate timing and scale of their deployment, and the resolution of potential site specific constraints that would impact their ultimate commercial deployment.

  3. Precise measurements of the total concentration of atmospheric CO2 and 13CO2/12CO2 isotopic ratio using a lead-salt laser diode spectrometer.

    PubMed

    Croizé, Laurence; Mondelain, Didier; Camy-Peyret, Claude; Delmotte, Marc; Schmidt, Martina

    2008-04-01

    We have developed a tunable diode laser spectrometer, called SIMCO (spectrometer for isotopic measurements of CO(2)), for determining the concentrations of (12)CO(2) and (13)CO(2) in atmospheric air, from which the total concentration of CO(2) and the isotopic composition (expressed in delta units) delta(13)CO(2) are calculated. The two concentrations are measured using a pair of lines around 2290.1 cm(-1), by fitting a line profile model, taking into account the confinement narrowing effect to achieve a better accuracy. Using the Allan variance, we have demonstrated (for an integration time of 25 s) a precision of 0.1 ppmv for the total CO(2) concentration and of 0.3[per thousand] for delta(13)CO(2). The performances on atmospheric air have been tested during a 3 days campaign by comparing the SIMCO instrument with a gas chromatograph (GC) for the measurement of the total CO(2) concentration and with an isotopic ratio mass spectrometer (MS) for the isotopic composition. The CO(2) concentration measurements of SIMCO are in very good agreement with the GC data with a mean difference of Delta(CO(2))=0.16+/-1.20 ppmv for a comparison period of 45 h and the linearity of the concentration between the two instruments is also very good (slope of correlation: 0.9996+/-0.0003) over the range between 380 and 415 ppmv. For delta(13)CO(2), the comparison with the MS data shows a larger mean difference of Delta(delta(13)CO(2))=(-1.9+/-1.2)[per thousand], which could be partly related to small residual fluctuations of the overall SIMCO instrument response. PMID:18447517

  4. Molecular simulations of CO2 and mixed CH4-CO2 hydrates intercalated on smectites.

    NASA Astrophysics Data System (ADS)

    Martos-Villa, Rubén; Sainz-Díaz, C. Ignacio; Mata Campo, M. Pilar

    2013-04-01

    Natural gas hydrates (NGH) are crystalline compounds consisting of methane molecules encaged in cavities of a hydrogen-bonded network of water molecules. Gas hydrates have a general formula X?nH2O, where X is the guest molecule within a water cage, and n is the hydration number per guest molecule. The crystal structure sI consists of 46 water molecules per unit cell, forming two dodecahedron (small 512) and six tetradecahedron (large 51262) cages and is formed when small guest molecules such as methane or carbon dioxide are trapped. Considerable amounts of methane hydrates can be found in permafrost regions and sediments of the ocean floor in outer continental margin regions where medium pressures, low temperatures and high methane gas concentration in water can be reached. Gas hydrates are important because hydrate decomposition would cause the methane release into atmosphere causing great impact on Earth's climate. On the other hand, these NGH are seen as a potential major energy resource. The recent increase in anthropogenic CO2 gas released to the atmosphere and its contribution to global warming, makes necessary to investigate new ways of CO2 storage. The possibility of replacing natural gas by CO2 from NGH has been investigated. There are thermodynamic evidences that support the replacement in hydrate at appropriate conditions. The comparison of their hydrate phase equilibrium conditions suggests the occurrence of a transition zone between both hydrate equilibrium curves where CO2 hydrates can exist while CH4 hydrates dissociate into methane gas and water. Any further investigation of the mixed CH4-CO2 gas hydrate properties could lead to major breakthroughs in the fields of unconventional resource production and carbon sequestration. Clay minerals are major constituents of ocean sediments, the study of interactions between these minerals with hydrates on the seafloor can be useful to determine variations on hydrate stability field, and to know the properties

  5. 40 CFR 98.473 - Calculating CO2 received.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Calculating CO2 received. 98.473... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Injection of Carbon Dioxide § 98.473 Calculating CO2 received. (a) You must calculate and report the annual mass of CO2 received by pipeline using the procedures...

  6. SUBSURFACE PROPERTY RIGHTS: IMPLICATIONS FOR GEOLOGIC CO2 STORAGE

    EPA Science Inventory

    The paper discusses subsurface property rights as they apply to geologic sequestration (GS) of carbon dioxide (CO2). GS projects inject captured CO2 into deep (greater than ~1 km) geologic formations for the explicit purpose of avoiding atmospheric emission of CO2. Because of the...

  7. SUBSURFACE PROPERTY RIGHTS: IMPLICATIONS FOR GEOLOGIC CO2 SEQUESTRATION (PRESENTATION)

    EPA Science Inventory

    The paper discusses subsurface property rights as they apply to geologic sequestration (GS) of carbon dioxide (CO2). GS projects inject captured CO2 into deep (greater than ~1 km) geologic formations for the explicit purpose of avoiding atmospheric emission of CO2. Because of the...

  8. SUBSURFACE PROPERTY RIGHTS: IMPLICATIONS FOR GEOLOGIC CO2 SEQUESTRATION

    EPA Science Inventory

    The chapter discusses subsurface property rights as they apply to geologic sequestration (GS) of carbon dioxide (CO2). GS projects inject captured CO2 into deep (greater than ~1 km) geologic formations for the explicit purpose of avoiding atmospheric emission of CO2. Because of t...

  9. Temporal characteristics of atmospheric CO2 in urban Nanjing, China

    NASA Astrophysics Data System (ADS)

    Huang, Xiaoxian; Wang, Tijian; Talbot, Robert; Xie, Min; Mao, Huiting; Li, Shu; Zhuang, Bingliang; Yang, Xiuqun; Fu, Congbin; Zhu, Jialei; Huang, Xing; Xu, Runying

    2015-02-01

    Although China is a big carbon dioxide (CO2) emitter, in situ measurements of atmospheric CO2 are sparse in urban China. The mixing ratio of carbon dioxide (CO2) and its influencing factors in urban Nanjing were investigated in this study, from the 18th of January to the 31st of December 2011. The annual average mixing ratio of CO2 was 406.5 ± 20.0 ppmv over the study period. The signal analysis using the fast Fourier transform (FFT) algorithm showed that CO2 had different cycles as a result of multiple controlling factors. The seasonal and intra-seasonal fluctuations of CO2 were mainly caused by the terrestrial biospheric uptake and emission and atmospheric oscillation. The weekly variation of CO2 was largely influenced by traffic volume. The diurnal cycle of CO2 presented a bimodal pattern in winter (DJF) probably due to the rush hour emissions. The seasonal mean CO2/CO correlation slope varied from 0.024 ppmv/ppbv to 0.029 ppmv/ppbv, comparable to the fossil fuel combustion emission ratio. The diurnal pattern of CO2/CO was irregular, indicating random anthropogenic emissions in an urban area. Firework setting was a large source of CO2 during the Spring Festival holiday. The backward trajectories by the HYSPLIT model showed that the local anthropogenic emissions contributed the most to the high CO2 mixing ratio in the urban area.

  10. SURFACTANT ENHANCEMENT OF LIQUID CO2 FOR SURFACE CLEANING

    EPA Science Inventory

    The goal of this research activity is to develop the technical basis for a liquid CO2 (LCO2) based surface cleaning technology for metals and fabrics utilizing CO2 compatible surfactants. The use of CO2 is considered attractive for surface cleaning since it is abundant, cheap t...

  11. Experimental investigation of CO2 condensation process using cryogen

    NASA Astrophysics Data System (ADS)

    Lee, Cheonkyu; Yoo, Junghyun; Lee, Jisung; Park, Hana; Jeong, Sangkwon

    2014-01-01

    Carbon dioxide (CO2) is one of the dominant gas molecules that causes greenhouse effect, i.e. global warming. Numerous studies have been carried out to regulate the emission of CO2 to reduce greenhouse gas. The liquid CO2 is a convenient form of transportation compared to high-pressurized gaseous CO2. Therefore, the direct liquefaction mechanism of CO2 at low temperature draws technical attention recently. In particular, cold thermal energy of Liquefied Natural Gas (LNG) could be a candidate to condense gaseous CO2, especially in the LNG powered ship. In this paper, the detailed direct condensation process of CO2 using LN2 with intermittent solidification is investigated. Pressurized CO2 at 600 kPa is directly liquefied in a vessel by liquid nitrogen which is supplied into the coiled tube heat exchanger inside the CO2 vessel. The heat exchanger temperature is controlled from 130 K to 205 K to regulate the solidification and sublimation of CO2 by duty control with cryogenic solenoid valve. The characteristics of CO2 condensation process with cryogen are analyzed from the measurement results. The results show that the solidification causes the significant degradation of CO2 condensation heat transfer. Finally, the condensation rate with and without solidification is compared.

  12. 40 CFR 98.443 - Calculating CO2 geologic sequestration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CO2 concentration in the flow and the density of CO2 at standard conditions, according to Equation RR... well in quarter p (standard cubic meters). D = Density of CO2 at standard conditions (metric tons per... another facility without being injected into your well in quarter p (metric tons). D = Density of the...

  13. GLOBAL MITIGATION OF NON-CO2 GREENHOUSE GASES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The mitigation of noncarbon dioxide (non-CO2) greenhouse gas emissions can be a relatively inexpensive supplement to CO2-only mitigation strategies. The non-CO2 gases include methane (CH4), nitrous oxide (N2O), and a number of high global warming potential (high- GWP) or fluorinated gases. These ga...

  14. 40 CFR 98.423 - Calculating CO2 supply.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Calculating CO2 supply. 98.423 Section...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Carbon Dioxide § 98.423 Calculating CO2 supply. (a) Calculate the annual mass of CO2 captured, extracted, imported, or exported through each flow meter...

  15. 46 CFR 108.433 - Quantity of CO2: General.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Quantity of CO2: General. 108.433 Section 108.433 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.433 Quantity of CO2: General. Each CO2 system must...

  16. Designing an oscillating CO2 concentration experiment for field chambers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Questions have arisen about photosynthetic response to fluctuating carbon dioxide (CO2), which might affect yield in free-air CO2 enrichment (FACE) systems and in open top chambers. A few studies have been conducted based on CO2 controlled to cycles of fixed time-periods and fixed, large amplitude....

  17. EFFECTS OF CO2 ON COMPETITION BETWEEN RICE AND BARNYARDGRASS

    EPA Science Inventory

    The atmospheric CO2 concentration is increasing. ffects of elevated CO2 on rice production could occur not only through direct impacts to rice, but also indirectly via ecosystem responses. hanged competitiveness with elevated CO2 could occur between rice hich has the C3 type of p...

  18. 40 CFR 98.423 - Calculating CO2 supply.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Carbon Dioxide § 98.423 Calculating CO2 supply. (a) Except... process units that capture a CO2 stream and either measure it after segregation or do not segregate the... = Flow meter. (ii) For facilities with production process units that capture a CO2 stream and measure...

  19. 40 CFR 98.423 - Calculating CO2 supply.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Carbon Dioxide § 98.423 Calculating CO2 supply. (a) Except... process units that capture a CO2 stream and either measure it after segregation or do not segregate the... = Flow meter. (ii) For facilities with production process units that capture a CO2 stream and measure...

  20. Lipid accumulation and CO2 utilization of Nannochloropsis oculata in response to CO2 aeration.

    PubMed

    Chiu, Sheng-Yi; Kao, Chien-Ya; Tsai, Ming-Ta; Ong, Seow-Chin; Chen, Chiun-Hsun; Lin, Chih-Sheng

    2009-01-01

    In order to produce microalgal lipids that can be transformed to biodiesel fuel, effects of concentration of CO(2) aeration on the biomass production and lipid accumulation of Nannochloropsis oculata in a semicontinuous culture were investigated in this study. Lipid content of N. oculata cells at different growth phases was also explored. The results showed that the lipid accumulation from logarithmic phase to stationary phase of N. oculata NCTU-3 was significantly increased from 30.8% to 50.4%. In the microalgal cultures aerated with 2%, 5%, 10% and 15% CO(2), the maximal biomass and lipid productivity in the semicontinuous system were 0.480 and 0.142 g L(-1)d(-1) with 2% CO(2) aeration, respectively. Even the N. oculata NCTU-3 cultured in the semicontinuous system aerated with 15% CO(2), the biomass and lipid productivity could reach to 0.372 and 0.084 g L(-1)d(-1), respectively. In the comparison of productive efficiencies, the semicontinuous system was operated with two culture approaches over 12d. The biomass and lipid productivity of N. oculata NCTU-3 were 0.497 and 0.151 g L(-1)d(-1) in one-day replacement (half broth was replaced each day), and were 0.296 and 0.121 g L(-1)d(-1) in three-day replacement (three fifth broth was replaced every 3d), respectively. To optimize the condition for long-term biomass and lipid yield from N. oculata NCTU-3, this microalga was suggested to grow in the semicontinuous system aerated with 2% CO(2) and operated by one-day replacement. PMID:18722767

  1. Sensory Transduction of the CO2 Response of Guard Cells

    SciTech Connect

    Dr. Eduardo Zeiger

    2003-06-30

    Stomata have a key role in the regulation of gas exchange and intercellular CO2 concentrations of leaves. Guard cells sense internal and external signals in the leaf environment and transduce these signals into osmoregulatory processes that control stomatal apertures. This research proposal addresses the characterization of the sensory transduction of the CO2 signal in guard cells. Recent studies have shown that in Vicia leaves kept at constant light and temperature in a growth chamber, changes in ambient CO2 concentrations cause large changes in guard cell zeaxanthin that are linear with CO2-dependent changes in stomatal apertures. Research proposed here will test the hypothesis that zeaxanthin function as a transducer of CO2 signals in guard cells. Three central aspects of this hypothesis will be investigated: CO2 sensing by the carboxylation reaction of Rubisco in the guard cell chloroplast, which would modulate zeaxanthin concentrations via changes in lumen pH; transduction of the CO2 signal by zeaxanthin via a transducing cascade that controls guard cell osmoregulation; and blue light dependence of the CO2 signal transduction by zeaxanthin, required for the formation of an isomeric form of zeaxanthin that is physiologically active as a transducer. The role of Rubisco in CO2 sensing will be investigated in experiments characterizing the stomatal response to CO2 in the Arabidopsis mutants R100 and rca-, which have reduced rates of Rubisco-dependent carboxylation. The role of zeaxanthin as a CO2 transducer will be studied in npq1, a zeaxanthin-less mutant. The blue light-dependence of CO2 sensing will be studied in experiments characterizing the stomatal response to CO2 under red light. Arabidopsis mutants will also be used in further studies of an acclimation of the stomatal response to CO2, and a possible role of the xanthophyll cycle of the guard cell chloroplast in acclimations of the stomatal response to CO2. Studies on the osmoregulatory role of sucrose in

  2. CO2 Fixation into Novel CO2 Storage Materials Composed of 1,2-Ethanediamine and Ethylene Glycol Derivatives.

    PubMed

    Zhao, Tianxiang; Guo, Bo; Han, Limin; Zhu, Ning; Gao, Fei; Li, Qiang; Li, Lihua; Zhang, Jianbin

    2015-07-20

    A new CO2 fixation process into solid CO2 -storage materials (CO2 SMs) under mild conditions has been developed. The novel application of amine-glycol systems to the capture, storage, and utilization of CO2 with readily available 1,2-ethanediamine (EDA) and ethylene glycol derivatives (EGs) was demonstrated. Typically, the CO2 SMs were isolated in 28.9-47.5 % yields, followed by extensive characterization using (13) C NMR, XRD, and FTIR. We found that especially the resulting poly-ethylene-glycol-300-based CO2 SM (PCO2 SM) product could be processed into stable tablets for CO2 storage; the aqueous PCO2 SM solution exhibited remarkable CO2 capturing and releasing capabilities after multiple cycles. Most importantly, the EDA and PEG 300 released from PCO2 SM were found to act as facilitative surfactants for the multiple preparation of CaCO3 microparticles with nano-layer structure. PMID:25952008

  3. Determining CO2 storage potential during miscible CO2 enhanced oil recovery: noble gas and stable isotope tracers

    USGS Publications Warehouse

    Shelton, Jenna L.; McIntosh, Jennifer C.; Hunt, Andrew; Beebe, Thomas L; Parker, Andrew D; Warwick, Peter; Drake, Ronald; John E. McCray

    2016-01-01

    Rising atmospheric carbon dioxide (CO2) concentrations are fueling anthropogenic climate change. Geologic sequestration of anthropogenic CO2 in depleted oil reservoirs is one option for reducing CO2 emissions to the atmosphere while enhancing oil recovery. In order to evaluate the feasibility of using enhanced oil recovery (EOR) sites in the United States for permanent CO2 storage, an active multi-stage miscible CO2 flooding project in the Permian Basin (North Ward Estes Field, near Wickett, Texas) was investigated. In addition, two major natural CO2 reservoirs in the southeastern Paradox Basin (McElmo Dome and Doe Canyon) were also investigated as they provide CO2 for EOR operations in the Permian Basin. Produced gas and water were collected from three different CO2 flooding phases (with different start dates) within the North Ward Estes Field to evaluate possible CO2 storage mechanisms and amounts of total CO2 retention. McElmo Dome and Doe Canyon were sampled for produced gas to determine the noble gas and stable isotope signature of the original injected EOR gas and to confirm the source of this naturally-occurring CO2. As expected, the natural CO2 produced from McElmo Dome and Doe Canyon is a mix of mantle and crustal sources. When comparing CO2 injection and production rates for the CO2 floods in the North Ward Estes Field, it appears that CO2 retention in the reservoir decreased over the course of the three injections, retaining 39%, 49% and 61% of the injected CO2 for the 2008, 2010, and 2013 projects, respectively, characteristic of maturing CO2 miscible flood projects. Noble gas isotopic composition of the injected and produced gas for the flood projects suggest no active fractionation, while δ13CCO2 values suggest no active CO2 dissolution into formation water, or mineralization. CO2 volumes capable of dissolving in residual formation fluids were also estimated along with the potential to store pure-phase supercritical CO2. Using a combination of

  4. CO(2) homeostasis during periodic breathing in obstructive sleep apnea.

    PubMed

    Berger, K I; Ayappa, I; Sorkin, I B; Norman, R G; Rapoport, D M; Goldring, R M

    2000-01-01

    The contribution of apnea to chronic hypercapnia in obstructive sleep apnea (OSA) has not been clarified. Using a model (D. M. Rapoport, R. G. Norman, and R. M. Goldring. J. Appl. Physiol. 75: 2302-2309, 1993), we previously illustrated failure of CO(2) homeostasis during periodic breathing resulting from temporal dissociation between ventilation and perfusion ("temporal V/Q mismatch"). This study measures acute kinetics of CO(2) during periodic breathing and addresses interapnea ventilatory compensation for maintenance of CO(2) homeostasis in 11 patients with OSA during daytime sleep (37-171 min). Ventilation and expiratory CO(2) and O(2) fractions were measured on a breath-by-breath basis by means of a tight-fitting full facemask. Calculations included CO(2) excretion, metabolic CO(2) production, and CO(2) balance (metabolic CO(2) production - exhaled CO(2)). CO(2) balance was tabulated for each apnea/hypopnea event-interevent cycle and as a cumulative value during sleep. Cumulative CO(2) balance varied (-3,570 to +1,388 ml). Positive cumulative CO(2) balance occurred in the absence of overall hypoventilation during sleep. For each cycle, positive CO(2) balance occurred despite increased interevent ventilation to rates as high as 45 l/min. This failure of CO(2) homeostasis was dependent on the event-to-interevent duration ratio. The results demonstrate that 1) periodic breathing provides a mechanism for acute hypercapnia in OSA, 2) acute hypercapnia during periodic breathing may occur without a decrease in average minute ventilation, supporting the presence of temporal V/Q mismatch, as predicted from our model, and 3) compensation for CO(2) accumulation during apnea/hypopnea may be limited by the duration of the interevent interval. The relationship of this acute hypercapnia to sustained chronic hypercapnia in OSA remains to be further explored. PMID:10642388

  5. CO2 storage capacity estimation: Methodology and gaps

    USGS Publications Warehouse

    Bachu, S.; Bonijoly, D.; Bradshaw, J.; Burruss, R.; Holloway, S.; Christensen, N.P.; Mathiassen, O.M.

    2007-01-01

    Implementation of CO2 capture and geological storage (CCGS) technology at the scale needed to achieve a significant and meaningful reduction in CO2 emissions requires knowledge of the available CO2 storage capacity. CO2 storage capacity assessments may be conducted at various scales-in decreasing order of size and increasing order of resolution: country, basin, regional, local and site-specific. Estimation of the CO2 storage capacity in depleted oil and gas reservoirs is straightforward and is based on recoverable reserves, reservoir properties and in situ CO2 characteristics. In the case of CO2-EOR, the CO2 storage capacity can be roughly evaluated on the basis of worldwide field experience or more accurately through numerical simulations. Determination of the theoretical CO2 storage capacity in coal beds is based on coal thickness and CO2 adsorption isotherms, and recovery and completion factors. Evaluation of the CO2 storage capacity in deep saline aquifers is very complex because four trapping mechanisms that act at different rates are involved and, at times, all mechanisms may be operating simultaneously. The level of detail and resolution required in the data make reliable and accurate estimation of CO2 storage capacity in deep saline aquifers practical only at the local and site-specific scales. This paper follows a previous one on issues and development of standards for CO2 storage capacity estimation, and provides a clear set of definitions and methodologies for the assessment of CO2 storage capacity in geological media. Notwithstanding the defined methodologies suggested for estimating CO2 storage capacity, major challenges lie ahead because of lack of data, particularly for coal beds and deep saline aquifers, lack of knowledge about the coefficients that reduce storage capacity from theoretical to effective and to practical, and lack of knowledge about the interplay between various trapping mechanisms at work in deep saline aquifers. ?? 2007 Elsevier Ltd

  6. On the proportionality between global temperature change and cumulative CO2 emissions during periods of net negative CO2 emissions

    NASA Astrophysics Data System (ADS)

    Zickfeld, Kirsten; MacDougall, Andrew H.; Damon Matthews, H.

    2016-05-01

    Recent research has demonstrated that global mean surface air warming is approximately proportional to cumulative CO2 emissions. This proportional relationship has received considerable attention, as it allows one to calculate the cumulative CO2 emissions (‘carbon budget’) compatible with temperature targets and is a useful measure for model inter-comparison. Here we use an Earth system model to explore whether this relationship persists during periods of net negative CO2 emissions. Negative CO2 emissions are required in the majority of emissions scenarios limiting global warming to 2 °C above pre-industrial, with emissions becoming net negative in the second half of this century in several scenarios. We find that for model simulations with a symmetric 1% per year increase and decrease in atmospheric CO2, the temperature change (ΔT) versus cumulative CO2 emissions (CE) relationship is nonlinear during periods of net negative emissions, owing to the lagged response of the deep ocean to previously increasing atmospheric CO2. When corrected for this lagged response, or if the CO2 decline is applied after the system has equilibrated with the previous CO2 increase, the ΔT versus CE relationship is close to linear during periods of net negative CO2 emissions. A proportionality constant—the transient climate response to cumulative carbon emissions (TCRE)‑ can therefore be calculated for both positive and net negative CO2 emission periods. We find that in simulations with a symmetric 1% per year increase and decrease in atmospheric CO2 the TCRE is larger on the upward than on the downward CO2 trajectory, suggesting that positive CO2 emissions are more effective at warming than negative emissions are at subsequently cooling. We also find that the cooling effectiveness of negative CO2 emissions decreases if applied at higher atmospheric CO2 concentrations.

  7. CO 2-water-basalt interaction. Numerical simulation of low temperature CO 2 sequestration into basalts

    NASA Astrophysics Data System (ADS)

    Gysi, Alexander P.; Stefánsson, Andri

    2011-09-01

    The interaction between CO 2-rich waters and basaltic glass was studied using reaction path modeling in order to get insight into the water-rock reaction process including secondary mineral composition, water chemistry and mass transfer as a function of CO 2 concentration and reaction progress ( ξ). The calculations were carried out at 25-90 °C and pCO 2 to 30 bars and the results were compared to recent experimental observations and natural systems. A thermodynamic dataset was compiled from 25 to 300 °C in order to simulate mineral saturations relevant to basalt alteration in CO 2-rich environment including revised key aqueous species for mineral dissolution reactions and apparent Gibbs energies for clay and carbonate solid solutions observed to form in nature. The dissolution of basaltic glass in CO 2-rich waters was found to be incongruent with the overall water composition and secondary mineral formation depending on reaction progress and pH. Under mildly acid conditions in CO 2 enriched waters (pH <6.5), SiO 2 and simple Al-Si minerals, Ca-Mg-Fe smectites and Ca-Mg-Fe carbonates predominated. Iron, Al and Si were immobile whereas the Mg and Ca mobility depended on the mass of carbonate formed and water pH. Upon quantitative CO 2 mineralization, the pH increased to >8 resulting in Ca-Mg-Fe smectite, zeolites and calcite formation, reducing the mobility of most dissolved elements. The dominant factor determining the reaction path of basalt alteration and the associated element mobility was the pH of the water. In turn, the pH value was determined by the concentration of CO 2 and extent of reaction. The composition of the carbonates depended on the mobility of Ca, Mg and Fe. At pH <6.5, Fe was in the ferrous oxidation state resulting in the formation of Fe-rich carbonates with the incorporation of Ca and Mg. At pH >8, the mobility of Fe and Mg was limited due to the formation of clays whereas Ca was incorporated into calcite, zeolites and clays. Competing

  8. Vibration characteristic of high power CO2 laser

    NASA Astrophysics Data System (ADS)

    Zhang, Kuo

    2015-02-01

    High power CO2 laser is widely used in various scientific, industrial and military applications. Vibration is a common phenomenon during laser working process, it will affect the working performance of high power CO2 laser, vibration must be strictly controlled in the condition where the laser pointing is required. This paper proposed a method to investigate the vibration characteristic of high power CO2 laser. An experiment device with vibration acceleration sensor was established to measure vibration signal of CO2 laser, the measured vibration signal was mathematically treated using space-frequency conversion, and then the vibration characteristic of high power CO2 laser can be obtained.

  9. Transpiration affects soil CO2 production in a dry grassland

    NASA Astrophysics Data System (ADS)

    Balogh, János; Fóti, Szilvia; Pintér, Krisztina; Burri, Susanne; Eugster, Werner; Papp, Marianna; Nagy, Zoltán

    2014-05-01

    Although soil CO2 efflux can be highly variable on the diel time scale, it is often measured during daytime only. However, to get a full understanding of soil CO2 efflux and its impact on carbon cycle processes, looking at diurnal processes is crucial. Therefore, our aim was to investigate how diel variation in soil CO2 efflux from a dry, sandy grassland in Hungary depends on variations in potential drivers, such as gross primary production (GPP) and evapotranspiration (ET). In order to reach this goal, we combined measurements of CO2 and H2O fluxes by eddy covariance, soil chambers and soil CO2 gradient system. Surface CO2 fluxes were partitioned into the three CO2 production components originating from the three soil layers to clarify the timing and the source of the CO2 within the top 50 cm of the soil. CO2 production rates during the growing season were higher during nighttime than during daytime. This diel course was not only driven by soil temperature and soil moisture, but also by ET. This was shown by changes of ET causing a hysteresis loop in the diel response of CO2 production to soil temperature. CO2 production was coupled to soil temperature at night and during midday (12-14 h), when ET remained relatively constant. However, when ET was changing over time, CO2 production was decoupled from soil temperature. In order to disentangle these effects, we carried out time-lag analyses between CO2 production and efflux residuals after having subtracted the main effects of soil temperature and soil water content from measured CO2 fluxes. The results showed a strong negative correlation between ET rates and residuals of soil CO2 production, and a less strong, but still significantly time-lagged positive correlation between GPP and residuals of soil CO2 production. Thus, we could show that there is a rapid negative response of soil CO2 production rates to transpiration (suggesting CO2 transport in the xylem stream) and a delayed positive response to GPP

  10. Floral CO2 reveals flower profitability to moths.

    PubMed

    Thom, Corinna; Guerenstein, Pablo G; Mechaber, Wendy L; Hildebrand, John G

    2004-06-01

    The hawkmoth Manduca sexta (Lepidoptera: Sphingidae), an experimentally favorable Lepidopteran that is highly sensitive to carbon dioxide (CO2), feeds on the nectar of a range of flowering plants, such as Datura wrightii (Solanaceae). Newly opened Datura flowers give off dramatically elevated levels of CO2 and offer ample nectar. Thus, floral CO2 emission could indicate food-source profitability. This study documents that foraging Manduca moths prefer surrogate flowers that emit high levels of CO2, characteristic of newly opened Datura flowers. We show for the first time that CO2 may play an important role in the foraging behavior of nectar-feeding insects. PMID:15303329

  11. Effects of Elevated CO2 Atmospheric CO2 on Soil Efflux in Conventional and Conservation Cropping Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elevated atmospheric CO2 can affect both the quantity and quality of plant tissues, which will impact the cycling and storage of carbon within plant/soil systems and the rate of CO2 release back to the atmosphere. Research is needed to more accurately quantify the effects of elevated CO2 on soil CO...

  12. Prairie Heating And CO2 Enrichment (PHACE) project: Semi-arid grassland responses to elevated CO2 and warming.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The new multi-factor Prairie Heating and CO2 Enrichment is a field experiment for subjecting a northern mixed-grass prairie, with and without weeds, to elevated CO2 and warming. This new experiment combines Free Air CO2 Enrichment (FACE) technology with a newly designed ceramic heater system for exp...

  13. Investigation on the Dielectric Properties of CO2 and CO2-Based Gases Based on the Boltzmann Equation Analysis

    NASA Astrophysics Data System (ADS)

    Sun, Hao; Wu, Yi; Rong, Mingzhe; Guo, Anxiang; Han, Guiquan; Lu, Yanhui

    2016-03-01

    In this paper, the dielectric properties of CO2, CO2/air, CO2/O2, CO2/N2, CO2/CF4, CO2/CH4, CO2/He, CO2/H2, CO2/NH3 and CO2/CO were investigated based on the Boltzmann equation analysis, in which the reduced critical electric field strength (E/N)cr of the gases was derived from the calculated electron energy distribution function (EEDF) by solving the Boltzmann transport equation. In this work, it should be noted that the fundamental data were carefully selected by the published experimental results and calculations to ensure the validity of the calculation. The results indicate that if He, H2, N2 and CH4, in which there are high ionization coefficients or a lack of attachment reactions, are added into CO2, the dielectric properties will decrease. On the other hand, air, O2, NH3 and CF4 (ranked in terms of (E/N)cr value in increasing order) have the potential to improve the dielectric property of CO2 at room temperature. supported in part by the National Key Basic Research Program of China (973 Program) (No. 2015CB251002), the Science and Technology Project Funds of the Grid State Corporation of China (No. SGSNK00KJJS1501564), National Natural Science Foundation of China (Nos. 51221005, 51577145), the Fundamental Research Funds for the Central Universities of China, and the Program for New Century Excellent Talents in University, China

  14. A CO2 concentration gradient facility for testing CO2 enrichment and soil effects on grassland ecosystem function

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Continuing increases in atmospheric CO2 concentrations mandate techniques for examining impacts on terrestrial ecosystems. Most experiments examine only two or a few levels of CO2 concentration and a single soil type, but if CO2 can be varied as a gradient from subambient to superambient concentra...

  15. CO2 (dry ice) cleaning system

    NASA Technical Reports Server (NTRS)

    Barnett, Donald M.

    1995-01-01

    Tomco Equipment Company has participated in the dry ice (solid carbon dioxide, CO2) cleaning industry for over ten years as a pioneer in the manufacturer of high density, dry ice cleaning pellet production equipment. For over four years Tomco high density pelletizers have been available to the dry ice cleaning industry. Approximately one year ago Tomco introduced the DI-250, a new dry ice blast unit making Tomco a single source supplier for sublimable media, particle blast, cleaning systems. This new blast unit is an all pneumatic, single discharge hose device. It meters the insertion of 1/8 inch diameter (or smaller), high density, dry ice pellets into a high pressure, propellant gas stream. The dry ice and propellant streams are controlled and mixed from the blast cabinet. From there the mixture is transported to the nozzle where the pellets are accelerated to an appropriate blasting velocity. When directed to impact upon a target area, these dry ice pellets have sufficient energy to effectively remove most surface coatings through dry, abrasive contact. The meta-stable, dry ice pellets used for CO2 cleaning, while labeled 'high density,' are less dense than alternate, abrasive, particle blast media. In addition, after contacting the target surface, they return to their equilibrium condition: a superheated gas state. Most currently used grit blasting media are silicon dioxide based, which possess a sharp tetrahedral molecular structure. Silicon dioxide crystal structures will always produce smaller sharp-edged replicas of the original crystal upon fracture. Larger, softer dry ice pellets do not share the same sharp-edged crystalline structures as their non-sublimable counterparts when broken. In fact, upon contact with the target surface, dry ice pellets will plastically deform and break apart. As such, dry ice cleaning is less harmful to sensitive substrates, workers and the environment than chemical or abrasive cleaning systems. Dry ice cleaning system

  16. CO2 (dry ice) cleaning system

    NASA Astrophysics Data System (ADS)

    Barnett, Donald M.

    1995-03-01

    Tomco Equipment Company has participated in the dry ice (solid carbon dioxide, CO2) cleaning industry for over ten years as a pioneer in the manufacturer of high density, dry ice cleaning pellet production equipment. For over four years Tomco high density pelletizers have been available to the dry ice cleaning industry. Approximately one year ago Tomco introduced the DI-250, a new dry ice blast unit making Tomco a single source supplier for sublimable media, particle blast, cleaning systems. This new blast unit is an all pneumatic, single discharge hose device. It meters the insertion of 1/8 inch diameter (or smaller), high density, dry ice pellets into a high pressure, propellant gas stream. The dry ice and propellant streams are controlled and mixed from the blast cabinet. From there the mixture is transported to the nozzle where the pellets are accelerated to an appropriate blasting velocity. When directed to impact upon a target area, these dry ice pellets have sufficient energy to effectively remove most surface coatings through dry, abrasive contact. The meta-stable, dry ice pellets used for CO2 cleaning, while labeled 'high density,' are less dense than alternate, abrasive, particle blast media. In addition, after contacting the target surface, they return to their equilibrium condition: a superheated gas state. Most currently used grit blasting media are silicon dioxide based, which possess a sharp tetrahedral molecular structure. Silicon dioxide crystal structures will always produce smaller sharp-edged replicas of the original crystal upon fracture. Larger, softer dry ice pellets do not share the same sharp-edged crystalline structures as their non-sublimable counterparts when broken. In fact, upon contact with the target surface, dry ice pellets will plastically deform and break apart. As such, dry ice cleaning is less harmful to sensitive substrates, workers and the environment than chemical or abrasive cleaning systems. Dry ice cleaning system

  17. Observational constraints on the global atmospheric CO2 budget

    NASA Technical Reports Server (NTRS)

    Tans, Pieter P.; Fung, Inez Y.; Takahashi, Taro

    1990-01-01

    Observed atmospheric concentrations of CO2 and data on the partial pressures of CO2 in surface ocean waters are combined to identify globally significant sources and sinks of CO2. The atmospheric data are compared with boundary layer concentrations calculated with the transport fields generated by a general circulation model (GCM) for specified source-sink distributions. In the model the observed north-south atmospheric concentration gradient can be maintained only if sinks for CO2 are greater in the Northern than in the Southern Hemisphere. The observed differences between the partial pressure of CO2 in the surface waters of the Northern Hemisphere and the atmosphere are too small for the oceans to be the major sink of fossil fuel CO2. Therefore, a large amount of the CO2 is apparently absorbed on the continents by terrestrial ecosystems.

  18. Economics show CO2 EOR potential in central Kansas

    USGS Publications Warehouse

    Dubois, M.K.; Byrnes, A.P.; Pancake, R.E.; Willhite, G.P.; Schoeling, L.G.

    2000-01-01

    Carbon dioxide (CO2) enhanced oil recovery (EOR) may be the key to recovering hundreds of millions of bbl of trapped oil from the mature fields in central Kansas. Preliminary economic analysis indicates that CO2 EOR should provide an internal rate of return (IRR) greater than 20%, before income tax, assuming oil sells for $20/bbl, CO2 costs $1/Mcf, and gross utilization is 10 Mcf of CO2/bbl of oil recovered. If the CO2 cost is reduced to $0.75/Mcf, an oil price of $17/bbl yields an IRR of 20%. Reservoir and economic modeling indicates that IRR is most sensitive to oil price and CO2 cost. A project requires a minimum recovery of 1,500 net bbl/acre (about 1 million net bbl/1-mile section) under a best-case scenario. Less important variables to the economics are capital costs and non-CO2 related lease operating expenses.

  19. Ab Initio Screening of CO2-philic Groups.

    PubMed

    Tian, Ziqi; Saito, Tomonori; Jiang, De-En

    2015-04-23

    Ab initio calculations were used to identify CO2-philic groups. Over 55 neutral molecules were screened for CO2 affinity via binding energetics. It is found that poly(ethylene oxide)s (PEO) oligomers with more than three repeating units are good CO2-binding groups, consistent with the high-performance of PEO-based materials for CO2/N2 separation. More interestingly, two triazole groups linked with a methylene chain are also excellent for CO2 binding with a favorable interaction of more than 28 kJ/mol, indicating that polymers or covalent-organic frameworks (COFs) with triazoles may be utilized for CO2 capture. This work provides a useful guide to introduce promising organic groups into polymeric membranes and COFs for CO2/N2 separation media. PMID:25825811

  20. CO2 Condensation Models for Mars

    NASA Technical Reports Server (NTRS)

    Colaprete, A.; Haberle, R.

    2004-01-01

    During the polar night in both hemispheres of Mars, regions of low thermal emission, frequently referred to as "cold spots", have been observed by Mariner 9, Viking and Mars Global Surveyor (MGS) spacecraft. These cold spots vary in time and appear to be associated with topographic features suggesting that they are the result of a spectral-emission effect due to surface accumulation of fine-grained frost or snow. Presented here are simulations of the Martian polar night using the NASA Ames General Circulation Cloud Model. This cloud model incorporates all the microphysical processes of carbon dioxide cloud formation, including nucleation, condensation and sedimentation and is coupled to a surface frost scheme that includes both direct surface condensation and precipitation. Using this cloud model we simulate the Mars polar nights and compare model results to observations from the Thermal Emission Spectrometer (TES) and the Mars Orbiter Laser Altimeter (MOLA). Model predictions of "cold spots" compare well with TES observations of low emissivity regions, both spatially and as a function of season. The model predicted frequency of CO2 cloud formation also agrees well with MOLA observations of polar night cloud echoes. Together the simulations and observations in the North indicate a distinct shift in atmospheric state centered about Ls 270 which we believe may be associated with the strength of the polar vortex.

  1. Plywood Inlays Thourgh CO2 Laser Cutting

    NASA Astrophysics Data System (ADS)

    Pires, Margarida C.; Araujo, J. L.; Teixeira, M. Ribau; Rodrigues, F. Carvalho

    1989-07-01

    Furniture with inlays is rather expensive. This is so on two accounts: Firstly, furniture with inlays is generally manufactured with solid wood.Secondly,wood carving and figure cutting are both time consuming and they produce a high rate of rejections. To add to it all the cutting and carving of minute figures requires an outstanding craftmanship. In fact the craftman is in most instance the artist and also the manufacturer. While desiring that the high artistic level is maintained in the industry the search for new method to produce inlays for furniture in not son expensive materials and to produce them in a repetitive and flexible way laser cutting of plywood was found to be quite suitable. This paper presents the charts for CO2 laser cutting of both positive and negatives in several types of plywood. The main problem is not so much the cutting of the positive and negatives pieces but to be able to cut the piece in a way that the fitting is done without any problems caused by the ever present charring effect, which takes palce at the edges of the cut pieces. To minimise this aspect positive and negative pieces have to be cut under stringent focusing conditions and with slight different scales. The condittions for our machine are presented.

  2. A centrifuge CO2 pellet cleaning system

    NASA Technical Reports Server (NTRS)

    Foster, C. A.; Fisher, P. W.; Nelson, W. D.; Schechter, D. E.

    1995-01-01

    An advanced turbine/CO2 pellet accelerator is being evaluated as a depaint technology at Oak Ridge National Laboratory (ORNL). The program, sponsored by Warner Robins Air Logistics Center (ALC), Robins Air Force Base, Georgia, has developed a robot-compatible apparatus that efficiently accelerates pellets of dry ice with a high-speed rotating wheel. In comparison to the more conventional compressed air 'sandblast' pellet accelerators, the turbine system can achieve higher pellet speeds, has precise speed control, and is more than ten times as efficient. A preliminary study of the apparatus as a depaint technology has been undertaken. Depaint rates of military epoxy/urethane paint systems on 2024 and 7075 aluminum panels as a function of pellet speed and throughput have been measured. In addition, methods of enhancing the strip rate by combining infra-red heat lamps with pellet blasting and by combining the use of environmentally benign solvents with the pellet blasting have also been studied. The design and operation of the apparatus will be discussed along with data obtained from the depaint studies.

  3. CO2 laser welding fused silica.

    SciTech Connect

    Reed, Scott T.; MacCallum, Danny O'Neill; Knorovsky, Gerald Albert

    2005-08-01

    The feasibility of laser welding of fused silica (aka quartz) has been demonstrated recently by others. An application requiring hermetic sealing of a thin, pressure-bearing quartz diaphragm to a thicker frame led us to explore this technique. We found that laser welding techniques normally used for metallic parts caused scorching and uneven melting. Contrary to standard practices (near focus, high travel speed, high power density), successful welds in fused silica required a broad heat source applied over a large area under a slow rotation to gradually heat the glass through the annealing, softening and finally working temperatures. Furthermore, good mechanical contact between the parts to be joined played an even more important role in this process than in typical metallic joints. A 50 W CO2 laser with 4 f.l. ZnSe2 lens and rotary head was used to weld 0.425 OD, 0.006-0.010 thick, disks to 0.500 OD tubing with 0.125 walls. Several joint geometries and beam orientations were investigated. Temperature profiles were measured and compared to an FEM thermal model. We will discuss the effects of laser power, travel speed, number of passes, joint geometry and part thicknesses on achieving hermeticity and cosmetically-acceptable joints.

  4. CO2 Budget and Rectification Airborne Study

    NASA Technical Reports Server (NTRS)

    Grainger, C. A.

    2004-01-01

    The main purpose of this award was to supply a platform for the airborne measurements of gases associated with the CO2 Budget and Regional Airborne Study (COBRA). The original program was to consist of three field programs: the first was to be in 1999, the second in 2000, and the third in 2001. At the end of the second field program, it was agreed that the science could better be served by making the measurements in northern Brazil, rather than in North America. The final North American program would be postponed until after two field programs in Brazil. A substantial amount of effort was diverted into making plans and preparations for the Brazil field programs. The Brazil field programs were originally scheduled to take place in the Fall of 2002 and Spring of 2003. Carrying out the field program in Brazil was going to logistically much more involved than a program in the US. Shipping of equipment, customs, and site preparations required work to begin many months prior to the actual measurement program. Permission to fly in that country was also not trivial and indeed proved to be a major obstacle. When we were not able to get permission to fly in Brazil for the 2002 portion of the experiment, the program was pushed back to 2003. When permission by the Brazilian government was not given in time for a Spring of 2003 field program, the experiment was postponed again to begin in the Fall of 2003.

  5. Advanced Airborne CO2 LAS System

    NASA Astrophysics Data System (ADS)

    Dobler, J. T.; Braun, M. G.; McGregor, D. P.; Erxleben, W. H.; Browell, E. V.; Harrison, F. W.

    2009-12-01

    A unique airborne Laser Absorption Spectroscopy (LAS) system has been developed by ITT Space Systems, LLC to address the needs of the National Research Council Decadal Survey Tier 2 mission for Active Sensing of CO2 Emissions over Nights, Days and Seasons (ASCENDS). This instrument has undergone multiple airborne field tests in cooperation with our partners at NASA Langley Research Center (LaRC). The instrument was built largely with off-the-shelf components and uses high reliability telecom components, including lasers, modulators and fiber amplifiers as the transmitter. Multiple wavelengths are transmitted simultaneously from a single collimator and the return signal is collected by a simple 8” telescope that is fiber coupled to a HgCdTe APD. The analog signal is sampled with a high resolution scope card housed in a National Instruments PXI chassis and the digitized signal is then passed through our custom-built software-based lock-in processing system which allows separation of the signals from the individual wavelengths. The separated signals are then used in the standard Differential Absorption Lidar (DIAL) relations to determine the integrated column differential optical depth. This presentation will give a detailed overview of this multi-frequency, single-beam, synchronous lock-in LAS instrument including the basic methodology of the measurement. Recent improvements in the lock-in methodology designed to eliminate the effects of multi- path fading and frequency dependence of the electronic components will also be discussed.

  6. Fire hazards and CO2 laser resurfacing.

    PubMed

    Wald, D; Michelow, B J; Guyuron, B; Gibb, A A

    1998-01-01

    The purpose of this study was to investigate the fire risk of laser resurfacing in the presence of supplemental oxygen. This study aims at defining safety parameters of variables such as laser energy level, oxygen flow rate, and "oxygen to laser target distance" when oxygen is delivered through a nasal cannula or nasopharyngeal tube. The typical operating room environment was simulated in the laboratory using the Yucatan minipig animal model. The energy source was a Coherent Ultrapulse CO2 laser. It was found that combustion did not occur at laser settings of 500 mJ, 50 W, 100 kHz, and a density of 5, used in conjunction with an oxygen flow rate of 6 liter/minute with the target area as close as 0.5 cm to the oxygen delivery. A total of 400 computer pattern generator treatments were delivered using this energy setting without observation of any combustion (p < 0.001). This provides evidence that while using even somewhat high laser settings and oxygen flow rate, laser induced fires can be avoided. We conclude that use of the laser in the presence of oxygen is safe, provided the target area is free of combustible fuels. Despite this assurance, laser mishaps are serious because they lead to both morbidity and mortality. It is our recommendation that close attention be constantly paid to all details, thus reducing the hazard potential of laser energy on local factors in an oxygen-rich environment. PMID:9427936

  7. Development of optical MEMS CO2 sensors

    NASA Astrophysics Data System (ADS)

    McNeal, Mark P.; Moelders, Nicholas; Pralle, Martin U.; Puscasu, Irina; Last, Lisa; Ho, William; Greenwald, Anton C.; Daly, James T.; Johnson, Edward A.; George, Thomas

    2002-09-01

    Inexpensive optical MEMS gas and chemical sensors offer chip-level solutions to environmental monitoring, industrial health and safety, indoor air quality, and automobile exhaust emissions monitoring. Previously, Ion Optics, Inc. reported on a new design concept exploiting Si-based suspended micro-bridge structures. The devices are fabricated using conventional CMOS compatible processes. The use of photonic bandgap (PBG) crystals enables narrow band IR emission for high chemical selectivity and sensitivity. Spectral tuning was accomplished by controlling symmetry and lattice spacing of the PBG structures. IR spectroscopic studies were used to characterize transmission, absorption and emission spectra in the 2 to 20 micrometers wavelength range. Prototype designs explored suspension architectures and filament geometries. Device characterization studies measured drive and emission power, temperature uniformity, and black body detectivity. Gas detection was achieved using non-dispersive infrared (NDIR) spectroscopic techniques, whereby target gas species were determined from comparison to referenced spectra. A sensor system employing the emitter/detector sensor-chip with gas cell and reflective optics is demonstrated and CO2 gas sensitivity limits are reported.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Ozone Radiative Feedback in Global Warming Simulations with CO2 and non-CO2 Forcings

    NASA Astrophysics Data System (ADS)

    Ponater, M.; Rieger, V.; Dietmüller, S.

    2015-12-01

    It has been found that ozone radiative feedback acts to reduce the climate sensitivity in global warming simulations including interactive atmospheric chemistry, if the radiative forcing origins from CO2 increase. The effect can be traced to a negative feedback from stratospheric ozone changes and it is amplified by a reduced positive feedback from stratospheric water vapor.These findings cannot be simply transferred to simulations in which the warming is driven by a non-CO2 radiative forcing. Using a perturbation of surface NOx and CO emissions as an example, we demonstrate that a tropospheric ozone feedback may have significant impacts on physical feedbacks. These interactions can act to an extent that the effect of a negative ozone feedback can be reversed by changes in other feedbacks, thus increasing the climate sensitivity instead of reducing it. We also address some conceptual issues showing up as chemical feedbacks are added to set of physical feedbacks in simulation with interactive chemistry.

  10. CO2-PENS: A CO2 Sequestration Systems Model Supporting Risk-Based Decisions

    NASA Astrophysics Data System (ADS)

    Stauffer, P. H.; Viswanathan, H. S.; Guthrie, G. D.; Pawar, R. J.; Kaszuba, J. P.; Carey, J. W.; Lichtner, P. C.; Ziock, H. J.; Dubey, M. K.; Olsen, S. C.; Chipera, S. J.; Fessenden-Rahn, J. E.

    2005-12-01

    The Zero Emissions Research and Technology (ZERT) project at the Los Alamos National Laboratory is studying the injection of CO2 into geologic repositories. We are formulating the problem as science based decision framework that can address issues of risk, cost, and technical requirements at all stages of the sequestration process. The framework is implemented in a system model that is capable of performing stochastic simulations to address uncertainty in different geologic sequestration scenarios, including injection into poorly characterized brine aquifers. Processes level laboratory experiments, field experiments, modeling, economic data, and risk theory are used to support the system level model that will be the basis for decision making. The current system model, CO2-PENS, is already proving to be useful in showing complex interactions between the different components of the framework. The system model also provides a consistent platform to document decisions made during the site selection, implementation, and closure periods.

  11. Interpenetrating Metal-Metalloporphyrin Framework for Selective CO2 Uptake and Chemical Transformation of CO2.

    PubMed

    Gao, Wen-Yang; Tsai, Chen-Yen; Wojtas, Lukasz; Thiounn, Timmy; Lin, Chu-Chieh; Ma, Shengqian

    2016-08-01

    Herein we report a robust primitive cubic (pcu)-topology metal-metalloporphyrin framework (MMPF), MMPF-18, which was constructed from a ubiquitous secondary building unit of a tetranuclear zinc cluster, Zn4(μ4-O)(-COO)6, and a linear organic linker of 5,15-bis(4-carboxyphenyl)porphyrin (H2bcpp). The strong π-π stacking from porphyrins and the lengthy H2bcpp ligand affords a 4-fold-interpenetrating network along with reduced void spaces and confined narrow channels. Thereby, MMPF-18 presents segmented pores and high-density metalloporphyrin centers for selective CO2 uptake over CH4 and size-selective chemical transformation of CO2 with epoxides forming cyclic carbonates under ambient conditions. PMID:27337152

  12. Supersonic Technology for CO2 Capture: A High Efficiency Inertial CO2 Extraction System

    SciTech Connect

    2010-07-01

    IMPACCT Project: Researchers at ATK and ACENT Laboratories are developing a device that relies on aerospace wind-tunnel technologies to turn CO2 into a condensed solid for collection and capture. ATK’s design incorporates a special nozzle that converges and diverges to expand flue gas, thereby cooling it off and turning the CO2 into solid particles which are removed from the system by a cyclonic separator. This technology is mechanically simple, contains no moving parts and generates no chemical waste, making it inexpensive to construct and operate, readily scalable, and easily integrated into existing facilities. The increase in the cost to coal-fired power plants associated with introduction of this system would be 50% less than current technologies.

  13. Monitoring and Modeling CO2 Dynamics in the Vadose Zone near an Abandoned Historic Oil Well: Implications for Detecting CO2 Leakage at Geological CO2 Sequestration Sites

    NASA Astrophysics Data System (ADS)

    Yang, C.; Romanak, K.; Hovorka, S.; Reedy, R. C.; Trevino, R.; Scanlon, B. R.

    2010-12-01

    Soil-gas monitoring is proposed for detecting CO2 leakage at geological CO2 sequestration sites. At the Cranfield oil field, about 25 km east of Natchez, Mississippi, an integrated near-surface monitoring program is being implemented where supercritical CO2 is being injected for enhanced oil recovery (EOR). The purpose of the study is to understand how natural factors may affect soil CO2 monitoring at geologic carbon storage sites. A near-surface observatory, constructed on an engineered well pad near a 1950’s era open pit and plugged and abandoned well, was used to monitor atmospheric parameters such as air temperature, relative humility, barometric pressure, wind speed and direction, solar radiation, and precipitation. Soil temperature, soil CO2 concentrations, water content, and matric potential were also monitored at various depths to a maximum of 5 m in the vadose zone. The integrated monitoring system was installed in September 2009 and continued collecting data each half hour for about 240 days. CO2 concentrations measured at 1.5 m depth are about two times that of atmospheric CO2 concentrations and show daily fluctuations. However, CO2 concentrations measured at 3 m depth decreased from 11% in November 2009 to 9% in January 2010, then gradually increased to 10.5% in June 2010. There should be no CO2 contribution from root respiration because the engineered pad is bare of vegetation. Monitored CO2 in the vadose zone at this site most likely is derived from oxidation of methane with a suspected source related to the 1950’s era plugged and abandoned well. A 1-D numerical model was also used to simulate variably saturated water flow, CO2 transport, CH4 oxidation for understanding mechanisms that dominate CO2 transport at this site. Results of this study suggest that CO2 transport in the vadose zone is very complicated and can be affected by many factors including precipitation, barometric pressure, soil temperature, oxidation of methane, and therefore may

  14. Effects of elevated CO2 concentrations on denitrifying and nitrifying popualtions at terrestrial CO2 leakeage analogous sites

    NASA Astrophysics Data System (ADS)

    Christine, Dictor Marie; Catherine, Joulian; Valerie, Laperche; Stephanie, Coulon; Dominique, Breeze

    2010-05-01

    CO2 capture and geological storage (CCS) is recognized to be an important option for carbon abatement in Europe. One of the risks of CCS is the leakage from storage site. A laboratory was conducted on soil samples sampled near-surface from a CO2 leakage analogous site (Latera, Italy) in order to evaluate the impact of an elevated soil CO2 concentration on terrestrial bacterial ecosystems form near surface terrestrial environments and to determine a potential bacterial indicator of CO2 leakage from storage site. Surveys were conducted along a 50m long transect across the vent centre, providing a spectrum of CO2 flux rates, soil gas concentrations and compositions (Beaubien et al., 2007). A bacterial diversity studies, performed by CE-SSCP technique, on a soil profile with increasing CO2 soil concentrations (from 0.3% to 100%) showed that a change on bacterial diversity was noted when CO2 concentration was above 50 % of CO2. From this result, 3 soil samples were taken at 70 cm depth in 3 distinct zones (background soil CO2 content, soil CO2 content of 20% and soil CO2 content of 50%). Then theses soil samples were incubated under closed jars flushed with different air atmospheres (20, 50 and 90 % of CO2) during 18 months. At initial, 3, 6, 12 and 18 months, some soil samples were collected in order to estimate the denitrifying, nitrifying activities as a function of CO2 concentration content and times. Theses enzymatic activities were chosen because one occurs under anaerobic conditions (denitrification) and the other occurs under aerobic conditions (nitrification). Both of them were involved in the nitrogen cycle and are major actors of soil function and groundwater quality preservation. Metabolic diversity using BIOLOG Ecoplates was determined on every soil samples. Physico-chemical parameters (e.g. pH, bulk chemistry, mineralogy) were analyzed to have some information about the evolution of the soil during the incubation with increasing soil CO2 concentrations

  15. Improved Efficiency of Miscible CO2 Floods and Enhanced Prospects for CO2 Flooding Heterogeneous Reservoirs

    SciTech Connect

    Grigg, Reid B.; Schechter, David S.

    1999-10-15

    The goal of this project is to improve the efficiency of miscible CO2 floods and enhance the prospects for flooding heterogeneous reservoirs. This report provides results of the second year of the three-year project that will be exploring three principles: (1) Fluid and matrix interactions (understanding the problems). (2) Conformance control/sweep efficiency (solving the problems. 3) Reservoir simulation for improved oil recovery (predicting results).

  16. The Wettability of Shale by CO2 and Its Impact on Geologic CO2 Sequestration

    NASA Astrophysics Data System (ADS)

    Guiltinan, E. J.; Cardenas, M. B.; Espinoza, D. N.; Yoon, H.; Dewers, T. A.

    2015-12-01

    The geologic sequestration of CO2 is widely considered as a potential solution for decreasing anthropogenic atmospheric CO2 emissions. Wettability of fluids within reservoir materials is a critical factor in determining the efficiency of structural and residual trapping, two major mechanisms of geologic sequestration. Individual reservoir minerals are often targeted for wettability studies. Current practice applies these results, recorded under laboratory conditions, to in-situ reservoir rock; however the wide variety of measured contact angles reported in the literature calls this practice into question. To address these issues and to study the wettability of shale caprock, resedimentation techniques are employed. These techniques allow for the creation of synthetic shales with controlled, homogeneous mineralogies. In addition, the systematic variation of the mineralogy allows for the characterization of shale wettability as a function of mineralogical composition. A novel design has been developed and used to conduct wettability experiments at reservoir conditions using high resolution X-ray computer tomography. Using this technique the wettability of resedimented shales and natural shales are compared at different reservoir conditions. Next, Lattice Boltzmann modelling methods are used to simulate capillary entry pressure into a shale capillary. Adhesion parameters along the wall are tuned to the results of the synthetic shales and heterogeneity is incorporated to estimate the capillary entry pressure into a natural shale. Understanding the mineralogical components of shale wetting allows for the prediction of capillary entry pressure based on shale mineralogy which can be used to help select secure CO2 storage sites.

  17. Ambient CO2, fish behaviour and altered GABAergic neurotransmission: exploring the mechanism of CO2-altered behaviour by taking a hypercapnia dweller down to low CO2 levels.

    PubMed

    Regan, Matthew D; Turko, Andy J; Heras, Joseph; Andersen, Mads Kuhlmann; Lefevre, Sjannie; Wang, Tobias; Bayley, Mark; Brauner, Colin J; Huong, Do Thi Thanh; Phuong, Nguyen Thanh; Nilsson, Göran E

    2016-01-01

    Recent studies suggest that projected rises of aquatic CO2 levels cause acid-base regulatory responses in fishes that lead to altered GABAergic neurotransmission and disrupted behaviour, threatening fitness and population survival. It is thought that changes in Cl(-) and HCO3 (-) gradients across neural membranes interfere with the function of GABA-gated anion channels (GABAA receptors). So far, such alterations have been revealed experimentally by exposing species living in low-CO2 environments, like many oceanic habitats, to high levels of CO2 (hypercapnia). To examine the generality of this phenomenon, we set out to study the opposite situation, hypothesizing that fishes living in typically hypercapnic environments also display behavioural alterations if exposed to low CO2 levels. This would indicate that ion regulation in the fish brain is fine-tuned to the prevailing CO2 conditions. We quantified pH regulatory variables and behavioural responses of Pangasianodon hypophthalmus, a fish native to the hypercapnic Mekong River, acclimated to high-CO2 (3.1 kPa) or low-CO2 (0.04 kPa) water. We found that brain and blood pH was actively regulated and that the low-CO2 fish displayed significantly higher activity levels, which were reduced after treatment with gabazine, a GABAA receptor blocker. This indicates an involvement of the GABAA receptor and altered Cl(-) and HCO3 (-) ion gradients. Indeed, Goldman calculations suggest that low levels of environmental CO2 may cause significant changes in neural ion gradients in P. hypophthalmus. Taken together, the results suggest that brain ion regulation in fishes is fine-tuned to the prevailing ambient CO2 conditions and is prone to disruption if these conditions change. PMID:26739687

  18. The Mechanism of Diopside-Water-Supercritical CO2 Reaction:Relevance to CO2 Sequestration

    NASA Astrophysics Data System (ADS)

    Jiang, D.; Dong, S.; Zhao, L.; Teng, H.

    2013-12-01

    In order to study fundamental mineral carbonation process and reaction extent relevance to CO2 geological sequestration, in situ Raman spectroscopy was used to detect the silicate mineral diopside (CaMgSi2O6)-H2O-scCO2 reaction. In the experiment, diopside bulk grain (0.09g) and grinded powder (0.09g, 200mesh) were put into the sample pool of in situ Raman spectroscopy apparatus in water-saturated condition (10μlH2O: experimental H2O mole fraction in CO2 is 8.1×10-2, solubility of H2O in CO2 at experimental condition is 4.8×10-3), setting at the temperature of 60 degrees centigrade and the pressure of 7.9MPa. Experiment was done following the Lambert-Beer's law:Iv=KLCI0, which shows that Raman intensity(Iv) is proportional to the substance concentration(C)(K, L and I0 are constant in this experiment). The Raman spectrum analysis was performed at the beginning day, day 13, day 28 and day 42 successively. The results indicate that at day 13, a new peak appeared at 1124cm-1 , revealing that in water-saturated scCO2 condition, diopside is converted to huntite (Mg3Ca(CO3)4). The intensity ratio of diopside(1014cm-1) and huntite varies from 4.51:1(beginning) to 2.59:1(day 13) and then to 3.46:1(day 28). However, at day 42, almost no huntite remained in the experiment settings. According to Beer's law, we can conclude that the concentration of huntite increased firstly and then decreased after day 13 until we could not detect it at day 49. The XRD, SEM and FTIR test at day 49 also support the conclusion above. The huntite might form at the very first stage and then got dissolved into HCO3-; further experiments need to be conducted to detect HCO3-. The Raman test on the bulk grain also shows a similar trend as powder, but the reaction of the grain is much slower than powder. Besides, from the test on the grain at day 28, the water film could been detected 100-150μm above the surface of the grain with the thickness of 50-150μm.

  19. Volumetrics of CO2 storage in deep saline formations.

    PubMed

    Steele-MacInnis, Matthew; Capobianco, Ryan M; Dilmore, Robert; Goodman, Angela; Guthrie, George; Rimstidt, J Donald; Bodnar, Robert J

    2013-01-01

    Concern about the role of greenhouse gases in global climate change has generated interest in sequestering CO(2) from fossil-fuel combustion in deep saline formations. Pore space in these formations is initially filled with brine, and space to accommodate injected CO(2) must be generated by displacing brine, and to a lesser extent by compression of brine and rock. The formation volume required to store a given mass of CO(2) depends on the storage mechanism. We compare the equilibrium volumetric requirements of three end-member processes: CO(2) stored as a supercritical fluid (structural or stratigraphic trapping); CO(2) dissolved in pre-existing brine (solubility trapping); and CO(2) solubility enhanced by dissolution of calcite. For typical storage conditions, storing CO(2) by solubility trapping reduces the volume required to store the same amount of CO(2) by structural or stratigraphic trapping by about 50%. Accessibility of CO(2) to brine determines which storage mechanism (structural/stratigraphic versus solubility) dominates at a given time, which is a critical factor in evaluating CO(2) volumetric requirements and long-term storage security. PMID:22916959

  20. Enhanced CO2 Dissolution in Heterogeneous Porous Media

    NASA Astrophysics Data System (ADS)

    Daniels, K.; Neufeld, J. A.; Bickle, M. J.; Hallworth, M. A.

    2014-12-01

    Long-term and secure geological storage of CO2 through technologies such as Carbon Capture and Storage (CCS) within reservoirs is seen as a technological means to reduce anthropogenic CO2 emissions. The long-term viability of this technology is reliant on the structural and secondary trapping of supercritical CO2 within heterogeneous reservoirs. Secondary trapping, primarily through the dissolution of CO2 into ambient reservoir brine to produce a denser fluid, is capable of retaining CO2 in the subsurface and thus reducing the risks of storage. To model secondary trapping we need to understand how the flow of CO2 through heterogeneous reservoir rocks enhances dissolution of supercritical CO2 in reservoir brines. Here we experimentally investigate the dissolution of CO2 in reservoir brines in layered, heterogeneous geological formations. Using analogue experiments, designed to approximate an enhanced oil recovery (EOR) setting, the processes of mixing, dispersion and dissolution are examined. These are compared against test results from non-layered, homogeneous porous media experiments. We find that heterogeneities significantly enhance mixing, particularly between adjacent porous layers. During fluid propagation, pore-scale viscous fingers grow and retreat, thereby providing an increased surface area between the flow and the ambient reservoir fluid. This enhanced mixing is predicted to substantially increase the dissolution of CO2 in reservoir brines. Both permeability and viscosity differences are found to have a significant effect on the interface between the two fluids, and therefore the likely amount of dissolution of CO2.

  1. Buoyant dispersal of CO2 during geological storage

    NASA Astrophysics Data System (ADS)

    Hesse, M. A.; Woods, A. W.

    2010-01-01

    Carbon capture and storage is currently the only technology that may allow significant reductions in CO2 emissions from large point sources. Seismic images of geological CO2 storage show the rise of CO2 is influenced by horizontal shales. The buoyant CO2 spreads beneath impermeable barriers until a gap allows its upward migration. The large number and small scale of these barriers makes the prediction of the CO2 migration path and hence the magnitude of CO2 trapping very challenging. We show that steady buoyancy dominated flows in complex geometries can be modeled as a cascade of flux partitioning events. This approach allows the analysis of two-dimensional plume dispersal from a horizontal injection well. We show that the plume spreads laterally with height y above the source according to (y/h)1/2 L, where L is the width of the shales and h is their vertical separation. The fluid volume below successive shale layers, and therefore the magnitude of trapped CO2, increase as (y/h)5/4 above the source, so that every additional layer of barriers traps more CO2 than the one below. Upscaling small scale flow barriers by reducing the vertical permeability, common in numerical simulations of CO2 storage, does not capture the dispersion and trapping of the CO2 plume by the flow barriers.

  2. Sequestration of dissolved CO2 in the Oriskany formation.

    PubMed

    Dilmore, Robert M; Allen, Douglas E; Jones, J Richard McCarthy; Hedges, Sheila W; Soong, Yee

    2008-04-15

    Experiments were conducted to determine the solubility of CO2 in a natural brine solution of the Oriskany formation under elevated temperature and pressure conditions. These data were collected at temperatures of 22 and 75 degrees C and pressures between 100 and 450 bar. Experimentally determined data were compared with CO2 solubility predictions using a model developed by Duan and Sun (Chem. Geol. 2003, 193, 257-271). Model results compare well with Oriskany brine CO2 solubility data collected experimentally, suggesting that the Duan and Sun model is a reliable tool for estimating solution CO2 capacity in high salinity aquifers in the temperature and pressure range evaluated. The capacity for the Oriskany formation to sequester dissolved CO2 was calculated using results of the solubility models, estimation of the density of CO2 saturated brine, and available geographic information system (GIS) information on the formation depth and thickness. Results indicate that the Oriskany formation can hold approximately 0.36 gigatonnes of dissolved CO2 if the full basin is considered. When only the region where supercritical CO2 can exist (temperatures greaterthan 31 degrees C and pressures greaterthan 74 bar) is considered, the capacity of the Oriskany formation to sequester dissolved CO2 is 0.31 gigatonnes. The capacity estimate considering the potential to sequester free-phase supercritical CO2 if brine were displaced from formation pore space is 8.8 gigatonnes in the Oriskany formation. PMID:18497120

  3. Photorespiration in Air and High CO(2)-Grown Chlorella pyrenoidosa.

    PubMed

    Shelp, B J; Canvin, D T

    1981-12-01

    Oxygen inhibition of photosynthesis and CO(2) evolution during photorespiration were compared in high CO(2)-grown and air-grown Chlorella pyrenoidosa, using the artificial leaf technique at pH 5.0. High CO(2) cells, in contrast to air-grown cells, exhibited a marked inhibition of photosynthesis by O(2), which appeared to be competitive and similar in magnitude to that in higher C(3) plants. With increasing time after transfer to air, the photosynthetic rate in high CO(2) cells increased while the O(2) effect declined. Photorespiration, measured as the difference between (14)CO(2) and (12)CO(2) uptake, was much greater and sensitive to O(2) in high CO(2) cells. Some CO(2) evolution was also present in air-grown algae; however, it did not appear to be sensitive to O(2). True photosynthesis was not affected by O(2) in either case. The data indicate that the difference between high CO(2) and air-grown algae could be attributed to the magnitude of CO(2) evolution. This conclusion is discussed with reference to the oxygenase reaction and the control of photorespiration in algae. PMID:16662134

  4. Polyurethane Foam-Based Ultramicroporous Carbons for CO2 Capture.

    PubMed

    Ge, Chao; Song, Jian; Qin, Zhangfeng; Wang, Jianguo; Fan, Weibin

    2016-07-27

    A series of sustainable porous carbon materials were prepared from waste polyurethane foam and investigated for capture of CO2. The effects of preparation conditions, such as precarbonization, KOH to carbon precursor weight ratio, and activation temperature, on the porous structure and CO2 adsorption properties were studied for the purpose of controlling pore sizes and nitrogen content and developing high-performance materials for capture of CO2. The sample prepared at optimum conditions shows CO2 adsorption capacities of 6.67 and 4.33 mmol·g(-1) at 0 and 25 °C under 1 bar, respectively, which are comparable to those of the best reported porous carbons prepared from waste materials. The HCl treatment experiment reveals that about 80% of CO2 adsorption capacity arises from physical adsorption, while the other 20% is due to the chemical adsorption originated from the interaction of basic N groups and CO2 molecules. The relationship between CO2 uptake and pore size at different temperatures indicates that the micropores with pore size smaller than 0.86 and 0.70 nm play a dominant role in the CO2 adsorption at 0 and 25 °C, respectively. It was found that the obtained carbon materials exhibited high recyclability and high selectivity to adsorption of CO2 from the CO2 and N2 mixture. PMID:27376177

  5. Drilling and production - Economics show CO2 EOR potential

    USGS Publications Warehouse

    Dubois, M.K.; Byrnes, A.P.

    2000-01-01

    CO2 EOR may be the key to recovering hundreds of millions of bbl of trapped oil from the mature fields in central Kansas. A simple model aided in assessing the economics of CO2 EOR for central Kansas and the Midcontinent. The model used CO2 Prophet, a DOE freeware reservoir numerical simulation program, to determine reservoir performance, including injected and produced fluid rates, and CO2 utilization. Economic parameters, e.g., oil price, CO2 costs, capital costs, net revenue interest, production taxes, and lease operating expenses, are typical for anticipated conditions in the region and present price climate. Preliminary economic analysis shows that CO2 EOR should give an internal rate of return (IRR) > 20%, before income tax, assuming oil sells for $20/bbl, CO2 costs $1/million cu ft, and gross utilization is 10 million cu ft of CO2/bbl of oil recovered. If the CO2 is reduced to $0.75/million cu ft, an oil price of $17/bbl yields an IRR of 20%. Reservoir and economic modeling shows that IRR is most sensitive to oil price and CO2 cost.

  6. Sequestration of Dissolved CO2 in the Oriskany Formation

    SciTech Connect

    Dilmore, R.M.; Allen, D.E.; McCarthy-Jones, J.R.; Hedges, S.W.; Soong, Yee

    2008-04-15

    Experiments were conducted to determine the solubility of CO2 in a natural brine solution of the Oriskany formation under elevated temperature and pressure conditions. These data were collected at temperatures of 22 and 75 °C and pressures between 100 and 450 bar. Experimentally determined data were compared with CO2 solubility predictions using a model developed by Duan and Sun (Chem. Geol. 2003, 193, 257-271). Model results compare well with Oriskany brine CO2 solubility data collected experimentally, suggesting that the Duan and Sun model is a reliable tool for estimating solution CO2 capacity in high salinity aquifers in the temperature and pressure range evaluated. The capacity for the Oriskany formation to sequester dissolved CO2 was calculated using results of the solubility models, estimation of the density of CO2 saturated brine, and available geographic information system (GIS) information on the formation depth and thickness. Results indicate that the Oriskany formation can hold approximately 0.36 gigatonnes of dissolved CO2 if the full basin is considered. When only the region where supercritical CO2 can exist (temperatures greater than 31° C and pressures greater than 74 bar) is considered, the capacity of the Oriskany formation to sequester dissolved CO2 is 0.31 gigatonnes. The capacity estimate considering the potential to sequester free-phase supercritical CO2 if brine were displaced from formation pore space is 8.8 gigatonnes in the Oriskany formation.

  7. System-level modeling for geological storage of CO2

    SciTech Connect

    Zhang, Yingqi; Oldenburg, Curtis M.; Finsterle, Stefan; Bodvarsson, Gudmundur S.

    2006-04-24

    One way to reduce the effects of anthropogenic greenhousegases on climate is to inject carbon dioxide (CO2) from industrialsources into deep geological formations such as brine formations ordepleted oil or gas reservoirs. Research has and is being conducted toimprove understanding of factors affecting particular aspects ofgeological CO2 storage, such as performance, capacity, and health, safetyand environmental (HSE) issues, as well as to lower the cost of CO2capture and related processes. However, there has been less emphasis todate on system-level analyses of geological CO2 storage that considergeological, economic, and environmental issues by linking detailedrepresentations of engineering components and associated economic models.The objective of this study is to develop a system-level model forgeological CO2 storage, including CO2 capture and separation,compression, pipeline transportation to the storage site, and CO2injection. Within our system model we are incorporating detailedreservoir simulations of CO2 injection and potential leakage withassociated HSE effects. The platform of the system-level modelingisGoldSim [GoldSim, 2006]. The application of the system model is focusedon evaluating the feasibility of carbon sequestration with enhanced gasrecovery (CSEGR) in the Rio Vista region of California. The reservoirsimulations are performed using a special module of the TOUGH2 simulator,EOS7C, for multicomponent gas mixtures of methane and CO2 or methane andnitrogen. Using this approach, the economic benefits of enhanced gasrecovery can be directly weighed against the costs, risks, and benefitsof CO2 injection.

  8. Bubble nucleation in polymer–CO2 mixtures.

    PubMed

    Xu, Xiaofei; Cristancho, Diego E; Costeux, Stéphane; Wang, Zhen-Gang

    2013-10-28

    We combine density-functional theory with the string method to calculate the minimum free energy path of bubble nucleation in two polymer–CO2 mixture systems, poly(methyl methacrylate) (PMMA)–CO2 and polystyrene (PS)–CO2. Nucleation is initiated by saturating the polymer liquid with high pressure CO2 and subsequently reducing the pressure to ambient condition. Below a critical temperature (Tc), we find that there is a discontinuous drop in the nucleation barrier as a function of increased initial CO2 pressure (P0), as a result of an underlying metastable transition from a CO2-rich-vapor phase to a CO2-rich-liquid phase. The nucleation barrier is generally higher for PS–CO2 than for PMMA–CO2 under the same temperature and pressure conditions, and both higher temperature and higher initial pressure are required to lower the nucleation barrier for PS–CO2 to experimentally relevant ranges. Classical nucleation theory completely fails to capture the structural features of the bubble nucleus and severely underestimates the nucleation barrier. PMID:26029777

  9. Common freshwater cyanobacteria grow in 100% CO2.

    PubMed

    Thomas, David J; Sullivan, Shannon L; Price, Amanda L; Zimmerman, Shawn M

    2005-02-01

    Cyanobacteria and similar organisms produced most of the oxygen found in Earth's atmosphere, which implies that early photosynthetic organisms would have lived in an atmosphere that was rich in CO2 and poor in O2. We investigated the tolerance of several cyanobacteria to very high (>20 kPa) concentrations of atmospheric CO2. Cultures of Synechococcus PCC7942, Synechocystis PCC7942, Plectonema boryanum, and Anabaena sp. were grown in liquid culture sparged with CO2-enriched air. All four strains grew when transferred from ambient CO2 to 20 kPa partial pressure of CO2 (pCO2), but none of them tolerated direct transfer to 40 kPa pCO2. Synechococcus and Anabaena survived 101 kPa (100%) pCO2 when pressure was gradually increased by 15 kPa per day, and Plectonema actively grew under these conditions. All four strains grew in an anoxic atmosphere of 5 kPa pCO2 in N2. Strains that were sensitive to high CO2 were also sensitive to low initial pH (pH 5-6). However, low pH in itself was not sufficient to prevent growth. Although mechanisms of damage and survival are still under investigation, we have shown that modern cyanobacteria can survive under Earth's primordial conditions and that cyanobacteria-like organisms could have flourished under conditions on early Mars, which probably had an atmosphere similar to early Earth's. PMID:15711170

  10. Sequestering CO2 in the Built Environment

    NASA Astrophysics Data System (ADS)

    Constantz, B. R.

    2009-12-01

    Calera’s Carbonate Mineralization by Aqueous Precipitation (CMAP) technology with beneficial reuse has been called, “game-changing” by Carl Pope, Director of the Sierra Club. Calera offers a solution to the scale of the carbon problem. By capturing carbon into the built environment through carbonate mineralization, Calera provides a sound and cost-effective alternative to Geologic Sequestration and Terrestrial Sequestration. The CMAP technology permanently converts carbon dioxide into a mineral form that can be stored above ground, or used as a building material. The process produces a suite of carbonate-containing minerals of various polymorphic forms. Calera product can be substituted into blends with ordinary Portland cements and used as aggregate to produce concrete with reduced carbon, carbon neutral, or carbon negative footprints. For each ton of product produced, approximately half a ton of carbon dioxide can be sequestered using the Calera process. Coal and natural gas are composed of predominately istopically light carbon, as the carbon in the fuel is plant-derived. Thus, power plant CO2 emissions have relatively low δ13C values.The carbon species throughout the CMAP process are identified through measuring the inorganic carbon content, δ13C values of the dissolved carbonate species, and the product carbonate minerals. Measuring δ13C allows for tracking the flue gas CO2 throughout the capture process. Initial analysis of the capture of propane flue gas (δ13C ˜ -25 ‰) with seawater (δ13C ˜ -10 ‰) and industrial brucite tailings from a retired magnesium oxide plant in Moss Landing, CA (δ13C ˜ -7 ‰ from residual calcite) produced carbonate mineral products with a δ13C value of ˜ -20 ‰. This isotopically light carbon, transformed from flue gas to stable carbonate minerals, can be transferred and tracked through the capture process, and finally to the built environment. CMAP provides an economical solution to global warming by producing

  11. Impact of atmospheric CO2 levels on continental silicate weathering

    NASA Astrophysics Data System (ADS)

    Beaulieu, E.; GoddéRis, Y.; Labat, D.; Roelandt, C.; Oliva, P.; Guerrero, B.

    2010-07-01

    Anthropogenic sources are widely accepted as the dominant cause for the increase in atmospheric CO2 concentrations since the beginning of the industrial revolution. Here we use the B-WITCH model to quantify the impact of increased CO2 concentrations on CO2 consumption by weathering of continental surfaces. B-WITCH couples a dynamic biogeochemistry model (LPJ) and a process-based numerical model of continental weathering (WITCH). It allows simultaneous calculations of the different components of continental weathering fluxes, terrestrial vegetation dynamics, and carbon and water fluxes. The CO2 consumption rates are estimated at four different atmospheric CO2 concentrations, from 280 up to 1120 ppmv, for 22 sites characterized by silicate lithologies (basalt, granite, or sandstones). The sensitivity to atmospheric CO2 variations is explored, while temperature and rainfall are held constant. First, we show that under 355 ppmv of atmospheric CO2, B-WITCH is able to reproduce the global pattern of weathering rates as a function of annual runoff, mean annual temperature, or latitude for silicate lithologies. When atmospheric CO2 increases, evapotranspiration generally decreases due to progressive stomatal closure, and the soil CO2 pressure increases due to enhanced biospheric productivity. As a result, vertical drainage and soil acidity increase, promoting CO2 consumption by mineral weathering. We calculate an increase of about 3% of the CO2 consumption through silicate weathering (mol ha-1 yr-1) for 100 ppmv rise in CO2. Importantly, the sensitivity of the weathering system to the CO2 rise is not uniform and heavily depends on the climatic, lithologic, pedologic, and biospheric settings.

  12. Total (fumarolic + diffuse soil) CO2 output from Furnas volcano

    NASA Astrophysics Data System (ADS)

    Pedone, M.; Viveiros, F.; Aiuppa, A.; Giudice, G.; Grassa, F.; Gagliano, A. L.; Francofonte, V.; Ferreira, T.

    2015-10-01

    Furnas volcano, in São Miguel island (Azores), being the surface expression of rising hydrothermal steam, is the site of intense carbon dioxide (CO2) release by diffuse degassing and fumaroles. While the diffusive CO2 output has long (since the early 1990s) been characterized by soil CO2 surveys, no information is presently available on the fumarolic CO2 output. Here, we performed (in August 2014) a study in which soil CO2 degassing survey was combined for the first time with the measurement of the fumarolic CO2 flux. The results were achieved by using a GasFinder 2.0 tunable diode laser. Our measurements were performed in two degassing sites at Furnas volcano (Furnas Lake and Furnas Village), with the aim of quantifying the total (fumarolic + soil diffuse) CO2 output. We show that, within the main degassing (fumarolic) areas, the soil CO2 flux contribution (9.2 t day-1) represents a minor (~15 %) fraction of the total CO2 output (59 t day-1), which is dominated by the fumaroles (~50 t day-1). The same fumaroles contribute to ~0.25 t day-1 of H2S, based on a fumarole CO2/H2S ratio of 150 to 353 (measured with a portable Multi-GAS). However, we also find that the soil CO2 contribution from a more distal wider degassing structure dominates the total Furnas volcano CO2 budget, which we evaluate (summing up the CO2 flux contributions for degassing soils, fumarolic emissions and springs) at ~1030 t day-1.

  13. Understanding urban atmospheric CO2: Challenges and Opportunities

    NASA Astrophysics Data System (ADS)

    Pataki, D. E.; Ehleringer, J. R.; Forster, C. B.; Klewicki, J. C.; Pardyjak, E. R.; Peterson, R. E.; Steenburgh, W. J.; Tyler, B. J.

    2004-12-01

    Many studies have shown that atmospheric CO2 concentrations are elevated far above ambient levels in cities due to strong local sources. Measurements of urban atmospheric CO2 mixing ratio, its isotopic composition, and its sources and sinks provide opportunities to understand the local carbon cycle and biogeochemistry of cities, which is increasingly important in studies of regional and global change as well as urban sustainability and planning. In an ongoing project in the Salt Lake Valley, Utah, measurements of CO2 mixing ratio and the isotopic composition of CO2 have shown that vehicle exhaust significantly elevates CO2 mixing ratios above ambient, particularly in the wintertime when temperature inversions create stable conditions. Natural gas combustion also makes a large contribution to CO2 mixing ratio in the winter, but becomes negligible in the summer. However, the urban "forest" in the Salt Lake Valley plays an active role in influencing CO2 mixing ratio during the spring, summer, and fall through photosynthesis and respiration. Atmospheric CO2 measurements in the Salt Lake Valley are also useful in that they correlate with air pollutants such as aerosols, particularly in the wintertime when CO2 sources are dominated by combustion. The relationship between CO2 mixing ratio and other pollutants varies as a function of fuel source (natural gas versus gasoline) and meteorological variables that affect atmospheric chemistry of reactive compounds; therefore, these relationships provide additional information about sources and sinks for atmospheric constituents. Finally, CO2 is a stable atmospheric tracer in that it does not undergo chemical transformations in the atmosphere. Measurements in the Salt Lake Valley showed that the temporal and spatial distribution of CO2 in the wintertime may provide information about atmospheric transport during complex cold pools events if mixing ratios are monitored at multiple locations. These results suggest that studies of

  14. Modeling global atmospheric CO2 with improved emission inventories and CO2 production from the oxidation of other carbon species

    NASA Astrophysics Data System (ADS)

    Nassar, R.; Jones, D. B. A.; Suntharalingam, P.; Chen, J. M.; Andres, R. J.; Wecht, K. J.; Yantosca, R. M.; Kulawik, S. S.; Bowman, K. W.; Worden, J. R.; Machida, T.; Matsueda, H.

    2010-12-01

    The use of global three-dimensional (3-D) models with satellite observations of CO2 in inverse modeling studies is an area of growing importance for understanding Earth's carbon cycle. Here we use the GEOS-Chem model (version 8-02-01) CO2 mode with multiple modifications in order to assess their impact on CO2 forward simulations. Modifications include CO2 surface emissions from shipping (~0.19 Pg C yr-1), 3-D spatially-distributed emissions from aviation (~0.16 Pg C yr-1), and 3-D chemical production of CO2 (~1.05 Pg C yr-1). Although CO2 chemical production from the oxidation of CO, CH4 and other carbon gases is recognized as an important contribution to global CO2, it is typically accounted for by conversion from its precursors at the surface rather than in the free troposphere. We base our model 3-D spatial distribution of CO2 chemical production on monthly-averaged loss rates of CO (a key precursor and intermediate in the oxidation of organic carbon) and apply an associated surface correction for inventories that have counted emissions of CO2 precursors as CO2. We also explore the benefit of assimilating satellite observations of CO into GEOS-Chem to obtain an observation-based estimate of the CO2 chemical source. The CO assimilation corrects for an underestimate of atmospheric CO abundances in the model, resulting in increases of as much as 24% in the chemical source during May-June 2006, and increasing the global annual estimate of CO2 chemical production from 1.05 to 1.18 Pg C. Comparisons of model CO2 with measurements are carried out in order to investigate the spatial and temporal distributions that result when these new sources are added. Inclusion of CO2 emissions from shipping and aviation are shown to increase the global CO2 latitudinal gradient by just over 0.10 ppm (~3%), while the inclusion of CO2 chemical production (and the surface correction) is shown to decrease the latitudinal gradient by about 0.40 ppm (~10%) with a complex spatial structure

  15. Modeling global atmospheric CO2 with improved emission inventories and CO2 production from the oxidation of other carbon species

    SciTech Connect

    Nassar, Ray; Jones, DBA; Suntharalingam, P; Chen, j.; Andres, Robert Joseph; Wecht, K. J.; Yantosca, R. M.; Kulawik, SS; Bowman, K; Worden, JR; Machida, T; Matsueda, H

    2010-01-01

    The use of global three-dimensional (3-D) models with satellite observations of CO2 in inverse modeling studies is an area of growing importance for understanding Earth s carbon cycle. Here we use the GEOS-Chem model (version 8-02-01) CO2 mode with multiple modifications in order to assess their impact on CO2 forward simulations. Modifications include CO2 surface emissions from shipping (0.19 PgC yr 1), 3-D spatially-distributed emissions from aviation (0.16 PgC yr 1), and 3-D chemical production of CO2 (1.05 PgC yr 1). Although CO2 chemical production from the oxidation of CO, CH4 and other carbon gases is recognized as an important contribution to global CO2, it is typically accounted for by conversion from its precursors at the surface rather than in the free troposphere. We base our model 3-D spatial distribution of CO2 chemical production on monthly-averaged loss rates of CO (a key precursor and intermediate in the oxidation of organic carbon) and apply an associated surface correction for inventories that have counted emissions of CO2 precursors as CO2. We also explore the benefit of assimilating satellite observations of CO into GEOS-Chem to obtain an observation-based estimate of the CO2 chemical source. The CO assimilation corrects for an underestimate of atmospheric CO abundances in the model, resulting in increases of as much as 24% in the chemical source during May June 2006, and increasing the global annual estimate of CO2 chemical production from 1.05 to 1.18 Pg C. Comparisons of model CO2 with measurements are carried out in order to investigate the spatial and temporal distributions that result when these new sources are added. Inclusion of CO2 emissions from shipping and aviation are shown to increase the global CO2 latitudinal gradient by just over 0.10 ppm (3%), while the inclusion of CO2 chemical production (and the surface correction) is shown to decrease the latitudinal gradient by about 0.40 ppm (10%) with a complex spatial structure

  16. A 40-million-year history of atmospheric CO(2).

    PubMed

    Zhang, Yi Ge; Pagani, Mark; Liu, Zhonghui; Bohaty, Steven M; Deconto, Robert

    2013-10-28

    The alkenone-pCO2 methodology has been used to reconstruct the partial pressure of ancient atmospheric carbon dioxide (pCO2) for the past 45 million years of Earth's history (Middle Eocene to Pleistocene epochs). The present long-term CO2 record is a composite of data from multiple ocean localities that express a wide range of oceanographic and algal growth conditions that potentially bias CO2 results. In this study, we present a pCO2 record spanning the past 40 million years from a single marine locality, Ocean Drilling Program Site 925 located in the western equatorial Atlantic Ocean. The trends and absolute values of our new CO2 record site are broadly consistent with previously published multi-site alkenone-CO2 results. However, new pCO2 estimates for the Middle Miocene are notably higher than published records, with average pCO2 concentrations in the range of 400-500 ppm. Our results are generally consistent with recent pCO2 estimates based on boron isotope-pH data and stomatal index records, and suggest that CO2 levels were highest during a period of global warmth associated with the Middle Miocene Climatic Optimum (17-14 million years ago, Ma), followed by a decline in CO2 during the Middle Miocene Climate Transition (approx. 14 Ma). Several relationships remain contrary to expectations. For example, benthic foraminiferal δ(18)O records suggest a period of deglaciation and/or high-latitude warming during the latest Oligocene (27-23 Ma) that, based on our results, occurred concurrently with a long-term decrease in CO2 levels. Additionally, a large positive δ(18)O excursion near the Oligocene-Miocene boundary (the Mi-1 event, approx. 23 Ma), assumed to represent a period of glacial advance and retreat on Antarctica, is difficult to explain by our CO2 record alone given what is known of Antarctic ice sheet history and the strong hysteresis of the East Antarctic Ice Sheet once it has grown to continental dimensions. We also demonstrate that in the

  17. Sequestering CO2 in the Ocean: Options and Consequences

    NASA Astrophysics Data System (ADS)

    Rau, G. H.; Caldeira, K.

    2002-12-01

    The likelihood of negative climate and environmental impacts associated with increasing atmospheric CO2 has prompted serious consideration of various CO2 mitigation strategies. Among these are methods of capturing and storing of CO2 in the ocean. Two approaches that have received the most attention in this regard have been i) ocean fertilization to enhanced biological uptake and fixation of CO2, and ii) the chemical/mechanical capture and injection of CO2 into the deep ocean. Both methods seek to enhance or speed up natural mechanisms of CO2 uptake and storage by the ocean, namely i) the biological CO2 "pump" or ii) the passive diffusion of CO2 into the surface ocean and subsequent mixing into the deep sea. However, as will be reviewed, concerns about the capacity and effectiveness of either strategy in long-term CO2 sequestration have been raised. Both methods are not without potentially significant environmental impacts, and the costs of CO2 capture and injection (option ii) are currently prohibitive. An alternate method of ocean CO2 sequestration would be to react and hydrate CO2 rich waste gases (e.g., power plant flue gas) with seawater and to subsequently neutralize the resulting carbonic acid with limestone to produce calcium and bicarbonate ions in solution. This approach would simply speed up the CO2 uptake and sequestration that naturally (but very slowly) occurs via global carbonate weathering. This would avoid much of the increased acidity associated with direct CO2 injection while obviating the need for costly CO2 separation and capture. The addition of the resulting bicarbonate- and carbonate-rich solution to the ocean would help to counter the decrease in pH and carbonate ion concentration, and hence loss of biological calcification that is presently occurring as anthropogenic CO2 invades the ocean from the atmosphere. However, as with any approach to CO2 mitigation, the costs, impacts, risks, and benefits of this method need to be better understood

  18. Modeling global atmospheric CO2 with improved emission inventories and CO2 production from the oxidation of other carbon species

    NASA Astrophysics Data System (ADS)

    Nassar, R.; Jones, D. B. A.; Suntharalingam, P.; Chen, J. M.; Andres, R. J.; Wecht, K. J.; Yantosca, R. M.; Kulawik, S. S.; Bowman, K. W.; Worden, J. R.; Machida, T.; Matsueda, H.

    2010-07-01

    The use of global three-dimensional (3-D) models with satellite observations of CO2 in inverse modeling studies is an area of growing importance for understanding Earth's carbon cycle. Here we use the GEOS-Chem model (version 8-02-01) CO2 simulation with multiple modifications in order to assess their impact on CO2 forward simulations. Modifications include CO2 surface emissions from shipping (~0.19 Pg C/yr), 3-D spatially-distributed emissions from aviation (~0.16 Pg C/yr), and 3-D chemical production of CO2 (~1.05 Pg C/yr). Although CO2 chemical production from the oxidation of CO, CH4 and other carbon gases is recognized as an important contribution to global CO2, it is typically accounted for by conversion from its precursors at the surface rather than in the free troposphere. We base our model 3-D spatial distribution of CO2 chemical production on monthly-averaged loss rates of CO (a key precursor and intermediate in the oxidation of organic carbon) and apply an associated surface correction for inventories that have counted emissions of carbon precursor as CO2. We also explore the benefit of assimilating satellite observations of CO into GEOS-Chem to obtain an observation-based estimate of the CO2 chemical source. The CO assimilation corrects for an underestimate of atmospheric CO abundances in the model, resulting in increases of as much as 24% in the chemical source during May-June 2006, and increasing the global annual estimate of CO2 chemical production from 1.05 to 1.18 Pg C. Comparisons of model CO2 with measurements are carried out in order to investigate the spatial and temporal distributions that result when these new sources are added. Inclusion of CO2 emissions from shipping and aviation are shown to increase the global CO2 latitudinal gradient by just over 0.10 ppm (~3%), while the inclusion of CO2 chemical production (and the surface correction) is shown to decrease the latitudinal gradient by about 0.40 ppm (~10%) with a complex spatial

  19. CO2 Storage related Groundwater Impacts and Protection

    NASA Astrophysics Data System (ADS)

    Fischer, Sebastian; Knopf, Stefan; May, Franz; Rebscher, Dorothee

    2016-03-01

    Injection of CO2 into the deep subsurface will affect physical and chemical conditions in the storage environment. Hence, geological CO2 storage can have potential impacts on groundwater resources. Shallow freshwater can only be affected if leakage pathways facilitate the ascent of CO2 or saline formation water. Leakage associated with CO2 storage cannot be excluded, but potential environmental impacts could be reduced by selecting suitable storage locations. In the framework of risk assessment, testing of models and scenarios against operational data has to be performed repeatedly in order to predict the long-term fate of CO2. Monitoring of a storage site should reveal any deviations from expected storage performance, so that corrective measures can be taken. Comprehensive R & D activities and experience from several storage projects will enhance the state of knowledge on geological CO2 storage, thus enabling safe storage operations at well-characterised and carefully selected storage sites while meeting the requirements of groundwater protection.

  20. A Circular Bioeconomy with Biobased Products from CO2 Sequestration.

    PubMed

    Venkata Mohan, S; Modestra, J Annie; Amulya, K; Butti, Sai Kishore; Velvizhi, G

    2016-06-01

    The unprecedented climate change influenced by elevated concentrations of CO2 has compelled the research world to focus on CO2 sequestration. Although existing natural and anthropogenic CO2 sinks have proven valuable, their ability to further assimilate CO2 is now questioned. Thus, we highlight here the importance of biological sequestration methods as alternate and viable routes for mitigating climate change while simultaneously synthesizing value-added products that could sustainably fuel the circular bioeconomy. Four conceptual models for CO2 biosequestration and the synthesis of biobased products, as well as an integrated CO2 biorefinery model, are proposed. Optimizing and implementing this biorefinery model might overcome the limitations of existing sequestration methods and could help realign the carbon balance. PMID:27048926

  1. Polymer nanosieve membranes for CO2-capture applications

    NASA Astrophysics Data System (ADS)

    Du, Naiying; Park, Ho Bum; Robertson, Gilles P.; Dal-Cin, Mauro M.; Visser, Tymen; Scoles, Ludmila; Guiver, Michael D.

    2011-05-01

    Microporous organic polymers (MOPs) are of potential significance for gas storage, gas separation and low-dielectric applications. Among many approaches for obtaining such materials, solution-processable MOPs derived from rigid and contorted macromolecular structures are promising because of their excellent mass transport and mass exchange capability. Here we show a class of amorphous MOP, prepared by [2+3] cycloaddition modification of a polymer containing an aromatic nitrile group with an azide compound, showing super-permeable characteristics and outstanding CO2 separation performance, even under polymer plasticization conditions such as CO2/light gas mixtures. This unprecedented result arises from the introduction of tetrazole groups into highly microporous polymeric frameworks, leading to more favourable CO2 sorption with superior affinity in gas mixtures, and selective CO2 transport by presorbed CO2 molecules that limit access by other light gas molecules. This strategy provides a direction in the design of MOP membrane materials for economic CO2 capture processes.

  2. Concentrating on CO2: the Scandinavian and Arctic measurements.

    PubMed

    Bohn, Maria

    2011-01-01

    This article concerns atmospheric carbon dioxide (CO2) measurements made in Scandinavia and in the Arctic region before measurements started at Mauna Loa, Hawaii, in 1958. The CO2 hypothesis of climate change was one reason to measure atmospheric CO2 in the mid-1950s. The earlier history of CO2 measurements--for instance, the work of the chemist Kurt Buch--was also influential in this period. It is unclear when the CO2 hypothesis of climate change began to provide sufficient motivation for measurements, and the measurements may relate in a nonlinear way to the growth in popularity of the hypothesis. Discussions between meteorologist Carl-Gustaf Rossby at Stockholm Högskola and scientists in America reveal how different kinds of CO2 studies varied with regard to precision. PMID:21936192

  3. Heterogeneous radiolysis of CO 2 in the presence of zeolites

    NASA Astrophysics Data System (ADS)

    Garibov, A. A.; Velibekova, G. Z.; Agayev, T. N.

    Radiation catalytic activity of different zeolites Ca A, Na X, Na Y, LiNa Y, Ba M in CO 2 radiolysis has been investigated. This has led to studies in the catalyst porosity, the number of adsorbed CO 2 molecules and adsorption forces on their surface on the yield of CO 2 radiolysis products. A mechanism has been suggested for the observed CO 2 radiolysis processes over different zeolites. One of the possible ways to increase CO yield in radiolytic processes of CO 2 decomposition is to use various types of catalyst. (1-3) Therefore, the development of a scientific basis for appropriate catalyst selection is becoming of particular interest. For this purpose, heterogeneous CO 2 radiolysis in the presence of high-silica zeolites has been studied in this paper.

  4. Density-driven enhanced dissolution of injected CO2 during long-term CO2 geological storage

    NASA Astrophysics Data System (ADS)

    Zhang, Wei

    2013-10-01

    Geological storage of CO2 in deep saline formations is increasingly seen as a viable strategy to reduce the release of greenhouse gases into the atmosphere. However, possible leakage of injected CO2 from the storage formation through vertical pathways such as fractures, faults and abandoned wells is a huge challenge for CO2 geological storage projects. Thus, the density-driven fluid flow as a process that can accelerate the phase change of injected CO2 from supercritical phase into aqueous phase is receiving more and more attention. In this paper, we performed higher-resolution reactive transport simulations to investigate the possible density-driven fluid flow process under the `real' condition of CO2 injection and storage. Simulation results indicated that during CO2 injection and geological storage in deep saline formations, the higher-density CO2-saturated aqueous phase within the lower CO2 gas plume migrates downward and moves horizontally along the bottom of the formation, and the higher-density fingers within the upper gas plume propagate downward. These density-driven fluid flow processes can significantly enhance the phase transition of injected CO2 from supercritical phase into aqueous phase, consequently enhancing the effective storage capacity and long-term storage security of injected CO2 in saline formations.

  5. Noble gas and carbon isotopic evidence for CO2-driven silicate dissolution in a recent natural CO2 field

    NASA Astrophysics Data System (ADS)

    Dubacq, Benoît; Bickle, Mike J.; Wigley, Max; Kampman, Niko; Ballentine, Chris J.; Sherwood Lollar, Barbara

    2012-08-01

    Secure storage of anthropogenic carbon dioxide (CO2) in geological reservoirs requires predicting gas-water-rock interactions over millennial timescales. Noble gases and carbon isotope measurements can be used to shed light on the nature of competing dissolution-precipitation processes over different timescales, from the fast dissolution of gaseous CO2 in groundwater to more sluggish reactions involving dissolution and precipitation of newly formed minerals in the reservoir. Here we study a compilation of gas analyses including noble gases and δ13C of CO2 from nine different natural CO2 reservoirs. Amongst these reservoirs, the Bravo Dome CO2 field (New Mexico, USA) shows distinct geochemical trends which are explained by degassing of noble gases from groundwater altering the composition of the gas phase. This groundwater degassing is synchronous with the dissolution of CO2 in groundwater. Progressive creation of alkalinity via CO2-promoted mineral dissolution is required to explain the observed positive correlation between CO2/3He and δ13C of the gas phase, a unique feature of Bravo Dome. The differences between Bravo Dome and other natural CO2 reservoirs are likely explained by the more recent filling of Bravo Dome, reflecting CO2-water-rock interactions over thousands of years rather than over millions of years in older reservoirs.

  6. Annual and seasonal fCO2 and air-sea CO2 fluxes in the Barents Sea

    NASA Astrophysics Data System (ADS)

    Lauvset, S. K.; Chierici, M.; Counillon, F.; Omar, A.; Nondal, G.; Johannessen, T.; Olsen, A.

    2013-03-01

    The Barents Sea is the strongest CO2 sink in the Arctic region, yet estimates of the air-sea CO2 flux in this area show a large span reflecting uncertainty as well as significant variability both seasonally and regionally. Here we use a previously unpublished data set of seawater CO2 fugacity (fCO2), and map these data over the western Barents Sea through multivariable linear regressions with SeaWiFS/MODIS remote sensing and TOPAZ model data fields. We find that two algorithms are necessary in order to cover the full seasonal cycle, mainly because not all proxy variables are available for the entire year, and because variability in fCO2 is driven by different mechanisms in summer and winter. A comprehensive skill assessment indicates that there is a good overall correspondence between observations and predictions. The algorithms are also validated using two independent data sets, with good results. The gridded fCO2 fields reveal tight links between water mass distribution and fCO2 in all months, and particularly in winter. The seasonal cycle show peaks in the total air-sea CO2 influx in May and September, caused by respectively biological drawdown of CO2 and low sea ice concentration leaving a large open water area. For 2007 the annual average air-sea CO2 flux is - 48 ± 5 gC m- 2, which is comparable to previous estimates.

  7. Carboxylation of Phenols with CO2 at Atmospheric Pressure.

    PubMed

    Luo, Junfei; Preciado, Sara; Xie, Pan; Larrosa, Igor

    2016-05-10

    A convenient and efficient method for the ortho-carboxylation of phenols under atmospheric CO2 pressure has been developed. This method provides an alternative to the previously reported Kolbe-Schmitt method, which requires very high pressures of CO2 . The addition of a trisubstituted phenol has proved essential for the successful carboxylation of phenols with CO2 at standard atmospheric pressure, allowing the efficient preparation of a broad variety of salicylic acids. PMID:26989848

  8. Simulating Remediation of CO2 Leakage from Geological Storage Sites

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Oldenburg, C. M.; Benson, S. M.

    2003-12-01

    One strategy to reduce net greenhouse gas emissions is to inject carbon dioxide (CO2) deep into subsurface formations where presumably it would be stored indefinitely. Although geologic storage formations will be carefully selected, CO2 injected into a target formation may unexpectedly migrate upwards and ultimately seep out at the ground surface, creating a potential hazard to human beings and ecosystems. In this case, CO2 that has leaked from the geologic storage site is considered a contaminant, and remediation strategies such as passive venting and active pumping are needed. The purpose of this study is to investigate remediation strategies for CO2 leakage from geologic storage sites. We use the integral finite-difference code TOUGH2 to simulate the remediation of CO2 in subsurface systems. We consider the components of water, CO2 and air, and model flow and transport in aqueous and gas phases subject to a variety of initial and boundary conditions including passive venting and active pumping. We have investigated the time it takes for a gas plume of CO2 to be removed from the vadose zone both by natural attenuation processes and by active extraction wells. The time for removal is parameterized in terms of a CO2 plume half-life, defined as the time required for one-half of the CO2 mass to be removed. Initial simulations show that barometric pressure fluctuations enhance the removal of CO2 from the vadose zone, but that CO2 trapped near the water table is difficult to remove by either passive or active remediation approaches. This work was supported by a Cooperative Research and Development Agreement (CRADA) between BP Corporation North America, as part of the CO2 Capture Project (CCP), and the U.S. Department of Energy (DOE) through the National Energy Technologies Laboratory (NETL), and by the U.S. Department of Energy under contract DE-AC03-76SF00098.

  9. Holiday CO2: Inference from the Salt Lake City data

    NASA Astrophysics Data System (ADS)

    Ryoo, J.; Fung, I. Y.; Ehleringer, J. R.; Stephens, B. B.

    2013-12-01

    A network of high-frequency CO2 sensors has been established in Salt Lake City (SLC), Utah (http://co2.utah.edu/), and the annual/monthly pattern of CO2 variability is consistent with a priori estimates of CO2 fluxes (McKain et al., 2012). Here we ask if short-term changes in anthropogenic sources can be detected, and present a case study of Thanksgiving holiday, when traffic and energy use patterns are expected to be different from that during the rest of the month. CO2 mole fraction is much higher during the Thanksgiving holidays than the other days in November 2008 for all 5 sites in SLC, and a similar pattern is found in other years. Taking into account that the wind speed is relatively low in downtown SLC compared to the other SLC sites, the downtown site is further investigated to minimize the meteorological influence on CO2. In order to understand the relative contributions to the high level of CO2 during the Thanksgiving holidays, we carried out a multiple linear regression (MLR) analysis of the rate of CO2 change against various sources. Mobile CO2 sources are assumed to be proportional to local traffic data and residential CO2 sources are assumed to depend exponentially on temperature. Vulcan data were used to specify the other anthropogenic sources (commercial, industrial, nonroad, electricity, aircraft, and cement). The MLR analysis shows that during the Thanksgiving holidays CO2 contributions from residential and commercial CO2 are larger than that during the rest of November, and mobile sources represent only a relatively small contribution. The study demonstrates the feasibility of detecting changes in urban source contributions using high-frequency measurements in combination with daily PBL height and local traffic volume data.

  10. Efficient electrochemical CO2 conversion powered by renewable energy

    DOE PAGESBeta

    Kauffman, Douglas R.; Thakkar, Jay; Siva, Rajan; Matranga, Christopher; Ohodnicki, Paul R.; Zeng, Chenjie; Jin, Rongchao

    2015-06-29

    Here, the catalytic conversion of CO2 into industrially relevant chemicals is one strategy for mitigating greenhouse gas emissions. Along these lines, electrochemical CO2 conversion technologies are attractive because they can operate with high reaction rates at ambient conditions. However, electrochemical systems require electricity, and CO2 conversion processes must integrate with carbon-free, renewable-energy sources to be viable on larger scales. We utilize Au25 nanoclusters as renewably powered CO2 conversion electrocatalysts with CO2 → CO reaction rates between 400 and 800 L of CO2 per gram of catalytic metal per hour and product selectivities between 80 and 95%. These performance metrics correspondmore » to conversion rates approaching 0.8–1.6 kg of CO2 per gram of catalytic metal per hour. We also present data showing CO2 conversion rates and product selectivity strongly depend on catalyst loading. Optimized systems demonstrate stable operation and reaction turnover numbers (TONs) approaching 6 × 106 mol CO2 molcatalyst–1 during a multiday (36 hours total hours) CO2electrolysis experiment containing multiple start/stop cycles. TONs between 1 × 106 and 4 × 106 molCO2 molcatalyst–1 were obtained when our system was powered by consumer-grade renewable-energy sources. Daytime photovoltaic-powered CO2 conversion was demonstrated for 12 h and we mimicked low-light or nighttime operation for 24 h with a solar-rechargeable battery. This proof-of-principle study provides some of the initial performance data necessary for assessing the scalability and technical viability of electrochemical CO2 conversion technologies. Specifically, we show the following: (1) all electrochemical CO2 conversion systems will produce a net increase in CO2 emissions if they do not integrate with renewable-energy sources, (2) catalyst loading vs activity trends can be used to tune process rates and product distributions, and (3) state-of-the-art renewable-energy technologies

  11. Enhanced stabilization of vesicles by compressed CO2.

    PubMed

    Li, Wei; Zhang, Jianling; Cheng, Siqing; Han, Buxing; Zhang, Chaoxing; Feng, Xiaoying; Zhao, Yueju

    2009-01-01

    In this work, we studied the effect of compressed CO2 on the stability of vesicles formed in a dodecyltrimethylammonium bromide (DTAB)/sodium dodecyl sulfate (SDS) mixed surfactant system by combination of phase behavior and turbidity study, and UV-vis and fluorescence techniques. It was discovered that compressed CO2 could enhance the stability of vesicles significantly. This new and effective method to stabilize vesicles has some unique advantages over conventional methods. For example, the size and stability of the vesicles can be easily controlled by CO2 pressure; the method is greener because CO2 is a green reagent and it can be released completely after depressurization, which simplifies postseparation processes in applications. The main reason for CO2 to stabilize the vesicles is that CO2 molecules can insert into the hydrophobic bilayer region to enhance the rigidity of the vesicle film and reduce the size of the vesicles, which is different from that of conventional cosolvents (e.g., alcohols) used to stabilize vesicles. On the basis of this discovery, we developed a method to prepare hollow silica spheres using tetraethoxysilane as the precursor and CO2-stabilized vesicles as the template, in which CO2 acts as both the stabilizer of the vesicular template and the catalyst for the hydrolysis reaction of the precursor, and other cosolvents and catalysts are not required. Besides, the size of the silica hollow spheres prepared can be controlled by the pressure of CO2. PMID:19049396

  12. Olfactory receptor response to CO2 in bullfrogs.

    PubMed

    Coates, E L; Ballam, G O

    1990-05-01

    In vivo electrophysiological recordings of olfactory receptor cells of the bullfrog (Rana catesbeiana) exhibit a receptor response to CO2 concentrations as low as 0.5%. The amplitude of the electroolfactogram (EOG) increased with an increase in the CO2 concentration delivered to the olfactory epithelium. Likewise, there was a significant increase in the decay time (time from 90 to 10% peak EOG amplitude) with an increase in CO2. The EOG rise time (time from 10 to 90% peak EOG amplitude) and the EOG response latency (time from beginning of CO2 pulse to beginning of EOG response) significantly decreased, whereas the plateau time (time from 90% rising phase to 90% falling phase of the peak EOG amplitude) was not significantly altered by an increase in CO2. These results indicate that low concentrations of CO2, below normal end expiratory CO2 concentrations, stimulate olfactory receptor cells. These results support our proposal that the ventilatory depression observed in response to upper airway CO2 in reptiles and amphibians is mediated by CO2-sensitive olfactory receptor cells. PMID:2110785

  13. Potential of Microbes to Increase Geologic CO2 Storage Security

    NASA Astrophysics Data System (ADS)

    Gerlach, R.; Mitchell, A. C.; Ebigbo, A.; Phillips, A.; Cunningham, A. B.

    2011-12-01

    Geologic Carbon Capture and Storage (CCS) involves the injection of supercritical CO2 into underground formations such as brine aquifers where microbe-rock-fluid interactions will occur. These interactions may be important for the long-term fate of the injected CO2. Concepts and results will be presented from bench to meso-scale experiments focusing on the utility of attached microorganisms and biofilms to enhance storage security of injected CO2, via mineral-trapping, solubility trapping, formation trapping, and leakage reduction. Batch and flow experiments at atmospheric and geologic CO2 storage-relevant pressures have demonstrated the ability of microbial biofilms to decrease the permeability of natural and artificial porous media, survive the exposure to scCO2, and facilitate the conversion of CO2 into long-term stable carbonate phases as well as increase the solubility of CO2 in brines. Recent work has focused on small and large scale (75 cm diameter, 38 cm high sandstone) radial flow systems as well as the molecular characterization and isolation of microbes from geologic carbon sequestration-relevant environments. Methods for microscopic and macroscopic visualization of relevant processes from the pore to the bulk scale are being developed and have been proven to be essential tools in establishing the necessary understanding to increase CO2 storage security. As a result, reactive transport models describing the influence of biological processes on CO2 storage security have been developed and are continuously being modified to include relevant processes.

  14. Sedimentary reservoir oxidation during geologic CO2 sequestration

    NASA Astrophysics Data System (ADS)

    Lammers, Laura N.; Brown, Gordon E.; Bird, Dennis K.; Thomas, Randal B.; Johnson, Natalie C.; Rosenbauer, Robert J.; Maher, Katharine

    2015-04-01

    Injection of carbon dioxide into subsurface geologic reservoirs during geologic carbon sequestration (GCS) introduces an oxidizing supercritical CO2 phase into a subsurface geologic environment that is typically reducing. The resulting redox disequilibrium provides the chemical potential for the reduction of CO2 to lower free energy organic species. However, redox reactions involving carbon typically require the presence of a catalyst. Iron oxide minerals, including magnetite, are known to catalyze oxidation and reduction reactions of C-bearing species. If the redox conditions in the reservoir are modified by redox transformations involving CO2, such changes could also affect mineral stability, leading to dissolution and precipitation reactions and alteration of the long-term fate of CO2 in GCS reservoirs. We present experimental evidence that reservoirs with reducing redox conditions are favorable environments for the relatively rapid abiotic reduction of CO2 to organic molecules. In these experiments, an aqueous suspension of magnetite nanoparticles was reacted with supercritical CO2 under pressure and temperature conditions relevant to GCS in sedimentary reservoirs (95-210 °C and ∼100 bars of CO2). Hydrogen production was observed in several experiments, likely caused by Fe(II) oxidation either at the surface of magnetite or in the aqueous phase. Heating of the Fe(II)-rich system resulted in elevated PH2 and conditions favorable for the reduction of CO2 to acetic acid. Implications of these results for the long-term fate of CO2 in field-scale systems were explored using reaction path modeling of CO2 injection into reservoirs containing Fe(II)-bearing primary silicate minerals, with kinetic parameters for CO2 reduction obtained experimentally. The results of these calculations suggest that the reaction of CO2 with reservoir constituents will occur in two primary stages (1) equilibration of CO2 with organic acids resulting in mineral-fluid disequilibrium, and

  15. Global spatially explicit CO2 emission metrics for forest bioenergy

    NASA Astrophysics Data System (ADS)

    Cherubini, Francesco; Huijbregts, Mark; Kindermann, Georg; van Zelm, Rosalie; van der Velde, Marijn; Stadler, Konstantin; Strømman, Anders Hammer

    2016-02-01

    Emission metrics aggregate climate impacts of greenhouse gases to common units such as CO2-equivalents (CO2-eq.). Examples include the global warming potential (GWP), the global temperature change potential (GTP) and the absolute sustained emission temperature (aSET). Despite the importance of biomass as a primary energy supplier in existing and future scenarios, emission metrics for CO2 from forest bioenergy are only available on a case-specific basis. Here, we produce global spatially explicit emission metrics for CO2 emissions from forest bioenergy and illustrate their applications to global emissions in 2015 and until 2100 under the RCP8.5 scenario. We obtain global average values of 0.49 ± 0.03 kgCO2-eq. kgCO2-1 (mean ± standard deviation) for GWP, 0.05 ± 0.05 kgCO2-eq. kgCO2-1 for GTP, and 2.14·10-14 ± 0.11·10-14 °C (kg yr-1)-1 for aSET. We explore metric dependencies on temperature, precipitation, biomass turnover times and extraction rates of forest residues. We find relatively high emission metrics with low precipitation, long rotation times and low residue extraction rates. Our results provide a basis for assessing CO2 emissions from forest bioenergy under different indicators and across various spatial and temporal scales.

  16. Efficient electrochemical CO2 conversion powered by renewable energy.

    PubMed

    Kauffman, Douglas R; Thakkar, Jay; Siva, Rajan; Matranga, Christopher; Ohodnicki, Paul R; Zeng, Chenjie; Jin, Rongchao

    2015-07-22

    The catalytic conversion of CO2 into industrially relevant chemicals is one strategy for mitigating greenhouse gas emissions. Along these lines, electrochemical CO2 conversion technologies are attractive because they can operate with high reaction rates at ambient conditions. However, electrochemical systems require electricity, and CO2 conversion processes must integrate with carbon-free, renewable-energy sources to be viable on larger scales. We utilize Au25 nanoclusters as renewably powered CO2 conversion electrocatalysts with CO2 → CO reaction rates between 400 and 800 L of CO2 per gram of catalytic metal per hour and product selectivities between 80 and 95%. These performance metrics correspond to conversion rates approaching 0.8-1.6 kg of CO2 per gram of catalytic metal per hour. We also present data showing CO2 conversion rates and product selectivity strongly depend on catalyst loading. Optimized systems demonstrate stable operation and reaction turnover numbers (TONs) approaching 6 × 10(6) molCO2 molcatalyst(-1) during a multiday (36 h total hours) CO2 electrolysis experiment containing multiple start/stop cycles. TONs between 1 × 10(6) and 4 × 10(6) molCO2 molcatalyst(-1) were obtained when our system was powered by consumer-grade renewable-energy sources. Daytime photovoltaic-powered CO2 conversion was demonstrated for 12 h and we mimicked low-light or nighttime operation for 24 h with a solar-rechargeable battery. This proof-of-principle study provides some of the initial performance data necessary for assessing the scalability and technical viability of electrochemical CO2 conversion technologies. Specifically, we show the following: (1) all electrochemical CO2 conversion systems will produce a net increase in CO2 emissions if they do not integrate with renewable-energy sources, (2) catalyst loading vs activity trends can be used to tune process rates and product distributions, and (3) state-of-the-art renewable-energy technologies are sufficient

  17. Phase Behavior of Oxygen-Containing Polymers in CO2

    SciTech Connect

    Killic, Sevgi; Michalik, Stephen; Wang, Yang; Johnson, J.K.; Enick, R.M.; Beckman, E.J.

    2007-02-20

    The cloud point curves of a series of oxygen-containing polymers in CO2 were measured to attempt to deduce the effect of oxygen functional groups within a polymer on the polymer/CO2 phase behavior. The addition of an ether oxygen to a hydrocarbon polymer, either in the backbone or the side chain, enhances "CO2-philicity" by providing sites for specific interactions with CO2 as well as by enhancing the entropy of mixing by creating more flexible chains with higher free volume. Ab initio calculations show that both ether and ester oxygens provide very attractive interaction sites for CO2 molecules. The binding energy for an isolated ether oxygen with CO2 is larger in magnitude than that for a carbonyl oxygen/CO2 complex. However, acetate functionalized polymers are more CO2-soluble than polymers with only ether functionalities-possibly because acetate functional groups contain a total of three binding modes for CO2 interactions, compared with only one for the ether functional group. Experiments clearly indicate that adding a single methylene group as a spacer between a polymer backbone and either an ether or acetate group exhibits a strong deleterious effect on phase behavior. This effect cannot be explained from our ab initio calculations.

  18. Estimates of CO2 since the mid-Miocene

    NASA Astrophysics Data System (ADS)

    Stoll, Heather

    2016-04-01

    For past warm climates, direct CO2 determinations are unavailable. Our inferences of Antarctic ice sheet thresholds and climate sensitivity to CO2 are therefore strongly conditioned by the reliability of CO2 proxy reconstructions. For the Miocene, these rely heavily on proxies using the carbon isotopic fractionation of marine phytoplankton during photosynthesis (ep). While recent records are beginning to reveal more clearly the long term CO2 trends since the middle Miocene , the absolute CO2 concentrations are subject to higher uncertainty. This in turn influences the ability of models to simulate dynamic Antarctic ice sheet behavior in the context of expected ice sheet hysteresis. In this contribution, I discuss a new approach for estimating CO2 from published and new measurements of phytoplankton carbon isotopic fractionation using the ACTI-CO cell model. This approach accounts for the physiological adaptations made by phytoplankton cells to avoid falling below optimal photosynthetic rates as CO2 declines, the carbon concentrating mechanism. The model yields CO2 estimates which can be significantly (up to 2-fold) higher than those estimated from classic equations. Given the large degree of cooling since the late Miocene in extratropical sea surface temperature records, such CO2 estimates are consistent with a more conservative estimate of climate sensitivity over the last 12 Ma.

  19. Far-infrared spectra of CO2 clathrate hydrate frosts

    NASA Technical Reports Server (NTRS)

    Landry, J. C.; England, A. W.

    1993-01-01

    As a product of our interest in remote sensing of planetary ices, frost samples of CO2 clathrate hydrate were grown by depositing water vapor on a cooled surface and pressurizing the resulting water frost with CO2 gas. At pressures above the dissociation pressure of the clathrate, the samples exhibit an absorption peak at 75 cm (sup -1). At pressures below the dissociation pressure, the peak disappears. Since the free CO2 molecule does not have rotational or vibrational absorption in this region, the absorption is attributed to a CO2 rattling mode within a clathrate cage.

  20. CO2 electrochemical reduction via adsorbed halide anions

    NASA Astrophysics Data System (ADS)

    Ogura, Kotaro; Salazar-Villalpando, Maria D.

    2011-01-01

    The electrochemical reduction of CO2 was studied utilizing halide ions as electrolytes, specifically, aqueous solutions of KCl, KBr, KI. Electrochemical experiments were carried out in a laboratory-made, divided H-type cell. The working electrode was a copper mesh, while the counter and reference electrodes were a Pt wire and an Ag/AgCl electrode, respectively. The results of our work suggest a reaction mechanism for the electrochemical reduction of CO2 where the presence of Cu-X as the catalytic layer facilitates the electron transfer from the electrode to CO2. Electron-transfer to CO2 may occur via the X- ad(Br-, Cl-, I-)-C bond, which is formed by the electron flow from the specifically adsorbed halide anion to the vacant orbital of CO2. The stronger the adsorption of the halide anion to the electrode, the more strongly CO2 is restrained, resulting in higher CO2 reduction current. Furthermore, it is suggested that specifically adsorbed halide anions could suppress the adsorption of protons; leading to a higher hydrogen overvoltage. These effects may synergistically mitigate the over potential necessary for CO2 reduction, and thus increase the rate of electrochemical CO2 reduction.

  1. Simulation of CO2 release at 800 km altitude

    NASA Astrophysics Data System (ADS)

    Setayesh, A.

    1993-08-01

    The SOCRATES contamination-interaction code has been used to simulate the reactions of 0 + CO2 yields CO2(v) + O, O + CO2 - CO(v) + O2, and CO2 + H - CO + OH(v) at an altitude of 800 km in both ram and wake directions of the spacecraft. These simulations show that the radiation from these reactions can be measurable for the parameters which have been used in these calculations. The investigation carries out the simulations as much as 30 km from the spacecraft. The radiative intensity of CO(v) and OH(v) show the highest and lowest, respectively.

  2. Fabry-Perot Interferometer for Column CO2: Airborne

    NASA Technical Reports Server (NTRS)

    Kawa, S. R.; Heaps, W. S.; Mao, J.; Andrews, A. E.; Burris, J. F.; Miodek, M.; Georgieva, E.

    2002-01-01

    Global atmospheric CO2 measurements are essential to resolving significant discrepancies in our understanding of the global carbon budget and, hence, humankind's role in global climate change. The science measurement requirements for CO2 are, however, extremely demanding (precision approximately 0.3%). We are developing a novel application of a Fabry-Perot interferometer to detect spectral absorption of reflected sunlight by CO2 and O2 in the atmosphere that should be able to achieve sufficient sensitivity and signal-to-noise to measure column CO2 at the target specification. We are currently constructing a prototype instrument for deployment on aircraft. The aircraft version will measure total column CO2 and CO2 below the aircraft as well as O2, which allows normalization of CO2 column amounts for varying surface height and pressure. This instrument will be a valuable asset in carbon budget field studies as well as a useful tool for evaluating existing and future space-based CO2 measurements. We will present the instrument concept, sensitivity calculations, and the results of testing a bench system in the laboratory and outdoors on the ground. We will also discuss our plan for deployment on the aircraft and potential flight applications to the CO2 budget problem.

  3. Positive feedback between increasing atmospheric CO2 and ecosystem productivity

    NASA Astrophysics Data System (ADS)

    Gelfand, I.; Hamilton, S. K.; Robertson, G. P.

    2009-12-01

    Increasing atmospheric CO2 will likely affect both the hydrologic cycle and ecosystem productivity. Current assumptions that increasing CO2 will lead to increased ecosystem productivity and plant water use efficiency (WUE) are driving optimistic predictions of higher crop yields as well as greater availability of freshwater resources due to a decrease in evapotranspiration. The plant physiological response that drives these effects is believed to be an increase in carbon uptake either by (a) stronger CO2 gradient between the stomata and the atmosphere, or by (b) reduced CO2 limitation of enzymatic carboxylation within the leaf. The (a) scenario will lead to increased water use efficiency (WUE) in plants. However, evidence for increased WUE is mostly based on modeling studies, and experiments producing a short duration or step-wise increase in CO2 concentration (e.g. free-air CO2 enrichment). We hypothesize that the increase in atmospheric CO2 concentration is having a positive effect on ecosystem productivity and WUE. To investigate this hypothesis, we analyzed meteorological, ANPP, and soil CO2 flux datasets together with carbon isotopic ratio (13C/12C) of archived plant samples from the long term ecological research (LTER) program at Kellogg Biological Station. The datasets were collected between 1989 and 2007 (corresponding to an increase in atmospheric CO2 concentration of ~33 ppmv at Mauna Loa). Wheat (Triticum aestivum) samples taken from 1989 and 2007 show a significant decrease in the C isotope discrimination factor (Δ) over time. Stomatal conductance is directly related to Δ, and thus Δ is inversely related to plant intrinsic WUE (iWUE). Historical changes in the 13C/12C ratio (δ13C) in samples of a perennial forb, Canada goldenrod (Solidago canadensis), taken from adjacent successional fields, indicate changes in Δ upon uptake of CO2 as well. These temporal trends in Δ suggest a positive feedback between the increasing CO2 concentration in the

  4. Atmospheric CO2 Variability Observed From ASCENDS Flight Campaigns

    NASA Technical Reports Server (NTRS)

    Lin, Bing; Browell, Edward; Campbell, Joel; Choi, Yonghoon; Dobler, Jeremy; Fan, Tai-Fang; Harrison, F. Wallace; Kooi, Susan; Liu, Zhaoyan; Meadows, Byron; Nehrir, Amin; Obland, Michael; Plant, James; Yang, Melissa

    2015-01-01

    Significant atmospheric CO2 variations on various spatiotemporal scales were observed during ASCENDS flight campaigns. For example, around 10-ppm CO2 changes were found within free troposphere in a region of about 200x300 sq km over Iowa during a summer 2014 flight. Even over extended forests, about 2-ppm CO2 column variability was measured within about 500-km distance. For winter times, especially over snow covered ground, relatively less horizontal CO2 variability was observed, likely owing to minimal interactions between the atmosphere and land surface. Inter-annual variations of CO2 drawdown over cornfields in the Mid-West were found to be larger than 5 ppm due to slight differences in the corn growing phase and meteorological conditions even in the same time period of a year. Furthermore, considerable differences in atmospheric CO2 profiles were found during winter and summer campaigns. In the winter CO2 was found to decrease from about 400 ppm in the atmospheric boundary layer (ABL) to about 392 ppm above 10 km, while in the summer CO2 increased from 386 ppm in the ABL to about 396 ppm in free troposphere. These and other CO2 observations are discussed in this presentation.

  5. Hazardous indoor CO2 concentrations in volcanic environments.

    PubMed

    Viveiros, Fátima; Gaspar, João L; Ferreira, Teresa; Silva, Catarina

    2016-07-01

    Carbon dioxide is one of the main soil gases released silently and permanently in diffuse degassing areas, both in volcanic and non-volcanic zones. In the volcanic islands of the Azores (Portugal) several villages are located over diffuse degassing areas. Lethal indoor CO2 concentrations (higher than 10 vol %) were measured in a shelter located at Furnas village, inside the caldera of the quiescent Furnas Volcano (S. Miguel Island). Hazardous CO2 concentrations were detected not only underground, but also at the ground floor level. Multivariate regression analysis was applied to the CO2 and environmental time series recorded between April 2008 and March 2010 at Furnas village. The results show that about 30% of the indoor CO2 variation is explained by environmental variables, namely barometric pressure, soil water content and wind speed. The highest indoor CO2 concentrations were recorded during bad weather conditions, characterized by low barometric pressure together with rainfall periods and high wind speed. In addition to the spike-like changes observed on the CO2 time series, long-term oscillations were also identified and appeared to represent seasonal variations. In fact, indoor CO2 concentrations were higher during winter period when compared to the dry summer months. Considering the permanent emission of CO2 in various volcanic regions of the world, CO2 hazard maps are crucial and need to be accounted by the land-use planners and authorities. PMID:27155095

  6. CO2 Flux Inversion Error Analyses for Future Active Space CO2 Missions like ASCENDS

    NASA Astrophysics Data System (ADS)

    Baker, D. F.; Kawa, S. R.; Rayner, P. J.; Browell, E. V.; Menzies, R. T.; Abshire, J. B.

    2011-12-01

    We assess the ability of different proposed CO2 lidar measurement approaches to constrain surface CO2 fluxes, as part of the development of science requirements for NASA's ASCENDS mission. Observing system simulation experiments (OSSEs) are performed for different overall measurement uncertainty levels and vertical weightings to determine what designs will yield useful new information on the global carbon cycle. The OSSEs are based on a variational data assimilation method that models the measurements at the time and location they occur with minimal averaging and solves for the surface fluxes at regional spatial scales. Measurements are simulated using the PCTM off-line atmospheric transport model driven by GEOS5 analysis data (winds and vertical mixing parameters) and forced by realistic modeled CO2 fluxes. Both day- and night-side fluxes are estimated in weekly blocks at 4.5°x6° resolution (lat/lon) using a full year of simulated data. Error estimates are computed by direct comparison to the known truth; only random errors in the measurements and assumed flux prior are considered here. Relative measurement uncertainties and vertical averaging kernels have been derived for lidar measurements made using CO2 absorption lines in the 1.57 and 2.06 micron bands using realistic assumptions about clouds, aerosols, and surface reflectivity taken from CALIPSO and MODIS. Two measurement cases are considered for the 1.57 μm band, one using a vertical weighting function weighted to the mid- to lower troposphere, and one combining this with a function peaking near the tropopause. A third case is considered for measurements in the 2.06 μm band, with a vertical weighting peaking strongly near the surface. For each of these cases, three overall measurement uncertainty levels are examined (tied to reference uncertainties of 1.0, 0.5, and 0.2 ppm (1σ) at Railroad Valley, Nevada). OSSEs with simple measurement biases are run to test how the random-error-only findings hold in

  7. Partial pressure of CO2 and CO2 emission in a monsoon-driven hydroelectric reservoir (Danjiangkou Reservoir), China

    NASA Astrophysics Data System (ADS)

    Li, S. Y.; Zhang, Q. F.

    2013-06-01

    Hydroelectric reservoirs have been under sampled to establish them as sources or sinks of the atmospheric carbon dioxide (CO2). Such poor coverage is well known for subtropic, particularly monsoon driven reservoirs in China. Our study presented the spatiotemporal changes of the carbonate system and CO2 flux in a hydroelectric reservoir (Dangjiankou Reservoir) locating in a subtropical monsoon climate region. Our 21 filed surveys conducted during 2004-2011 revealed significantly spatial and monthly variations of surface water partial pressure of CO2 (pCO2) in the Reservoir. pCO2, showing higher concentrations in the wet and warm seasons, averaged 595 ± 545 µatm (ranging from 53-3751 µatm) in the reservoir surface, while substantially higher pCO2 (1132 ± 1220 µatm) was observed in the river downstream the dam. A clear pCO2 drawdown in the reservoir as water flows demonstrated a significantly descending order of Dan Reservoir > site close to dam > Han Reservoir. This spatial contrast can also be seen in the distributions of dissolved inorganic carbon and total alkalinity. Pronounced seasonality in pCO2 was controlled by seasonal monsoon rainfall, while photosynthetic CO2 uptake dominated spatial patterns and dry-month variability of pCO2. We further related pCO2 to water chemical properties and indicated that pCO2 had strong positive correlations with Si, TP and DOC, negative correlations with DO saturation, TN and Chl a, while weak correlations with other variables including biogenic elements. CO2 flux from the Reservoir surface showed a bottom average of 9 mmol m-2 d-2 in comparison with other hydroelectric reservoir in China. River downstream the dam had quite high flux of CO2 (119 mmol m-2 d-2), which was intermediate between temperate rivers and compared to global rivers' average. This means that water releasing from reservoir would be an important channel for atmospheric CO2 sources. The annual CO2 emission from the Danjiangkou Reservoir was estimated to be

  8. Our trial to develop a risk assessment tool for CO2 geological storage (GERAS-CO2GS)

    NASA Astrophysics Data System (ADS)

    Tanaka, A.; Sakamoto, Y.; Komai, T.

    2012-12-01

    We will introduce our researches about to develop a risk assessment tool named 'GERAS-CO2GS' (Geo-environmental Risk Assessment System, CO2 Geological Storage Risk Assessment System) for 'Carbon Dioxide Geological Storage (Geological CCS)'. It aims to facilitate understanding of size of impact of risks related with upper migration of injected CO2. For gaining public recognition about feasibility of Geological CCS, quantitative estimation of risks is essential, to let public knows the level of the risk: whether it is negligible or not. Generally, in preliminary hazard analysis procedure, potential hazards could be identified within Geological CCS's various facilities such as: reservoir, cap rock, upper layers, CO2 injection well, CO2 injection plant and CO2 transport facilities. Among them, hazard of leakage of injected C02 is crucial, because it is the clue to estimate risks around a specific injection plan in terms of safety, environmental protection effect and economy. Our risk assessment tool named GERAS-CO2GS evaluates volume and rate of retention and leakage of injected CO2 in relation with fractures and/or faults, and then it estimates impact of seepages on the surface of the earth. GERAS-CO2GS has four major processing segments: (a) calculation of CO2 retention and leakage volume and rate, (b) data processing of CO2 dispersion on the surface and ambient air, (c) risk data definition and (d) evaluation of risk. Concerning to the injection site, we defined a model, which is consisted from an injection well and a geological strata model: which involves a reservoir, a cap rock, an upper layer, faults, seabed, sea, the surface of the earth and the surface of the sea. For retention rate of each element of CO2 injection site model, we use results of our experimental and numerical studies on CO2 migration within reservoirs and faults with specific lithological conditions. For given CO2 injection rate, GERAS-CO2GS calculates CO2 retention and leakage of each segment

  9. Does atmospheric CO2 seasonality play an important role in governing the air-sea flux of CO2?

    NASA Astrophysics Data System (ADS)

    Halloran, P. R.

    2012-06-01

    The amplitude, phase, and form of the seasonal cycle of atmospheric CO2 concentrations varies on many time and space scales (Peters et al., 2007). Intra-annual CO2 variation is primarily driven by seasonal uptake and release of CO2 by the terrestrial biosphere (Machta et al., 1977; Buchwitz et al., 2007), with a small (Cadule et al., 2010; Heimann et al., 1998), but potentially changing (Gorgues et al., 2010) contribution from the ocean. Variability in the magnitude, spatial distribution, and seasonal drivers of terrestrial net primary productivity (NPP) will be induced by, amongst other factors, anthropogenic CO2 release (Keeling et al., 1996), land-use change (Zimov et al., 1999) and planetary orbital variability, and will lead to changes in CO2atm seasonality. Despite CO2atm seasonality being a dynamic and prominent feature of the Earth System, its potential to drive changes in the air-sea flux of CO2 has not previously (to the best of my knowledge) been explored. It is important that we investigate the impact of CO2atm seasonality change, and the potential for carbon-cycle feedbacks to operate through the modification of the CO2atm seasonal cycle, because the decision had been made to prescribe CO2atm concentrations (rather than emissions) within model simulations for the fifth IPCC climate assessment (Taylor et al., 2009). In this study I undertake ocean-model simulations within which different magnitude CO2atm seasonal cycles are prescribed. These simulations allow me to examine the effect of a change in CO2atm seasonal cycle magnitude on the air-sea CO2 flux. I then use an off-line model to isolate the drivers of the identified air-sea CO2 flux change, and propose mechanisms by which this change may come about. Three mechanisms are identified by which co-variability of the seasonal cycles in atmospheric CO2 concentration, and seasonality in sea-ice extent, wind-speed and ocean temperature, could potentially lead to changes in the air-sea flux of CO2 at mid

  10. Separation of biospheric and fossil fuel fluxes of CO2 by atmospheric inversion of CO2 and 14CO2 measurements: Observation System Simulations

    NASA Astrophysics Data System (ADS)

    Basu, Sourish; Bharat Miller, John; Lehman, Scott

    2016-05-01

    National annual total CO2 emissions from combustion of fossil fuels are likely known to within 5-10 % for most developed countries. However, uncertainties are inevitably larger (by unknown amounts) for emission estimates at regional and monthly scales, or for developing countries. Given recent international efforts to establish emission reduction targets, independent determination and verification of regional and national scale fossil fuel CO2 emissions are likely to become increasingly important. Here, we take advantage of the fact that precise measurements of 14C in CO2 provide a largely unbiased tracer for recently added fossil-fuel-derived CO2 in the atmosphere and present an atmospheric inversion technique to jointly assimilate observations of CO2 and 14CO2 in order to simultaneously estimate fossil fuel emissions and biospheric exchange fluxes of CO2. Using this method in a set of Observation System Simulation Experiments (OSSEs), we show that given the coverage of 14CO2 measurements available in 2010 (969 over North America, 1063 globally), we can recover the US national total fossil fuel emission to better than 1 % for the year and to within 5 % for most months. Increasing the number of 14CO2 observations to ˜ 5000 per year over North America, as recently recommended by the National Academy of Science (NAS) (Pacala et al., 2010), we recover monthly emissions to within 5 % for all months for the US as a whole and also for smaller, highly emissive regions over which the specified data coverage is relatively dense, such as for the New England states or the NY-NJ-PA tri-state area. This result suggests that, given continued improvement in state-of-the art transport models, a measurement program similar in scale to that recommended by the NAS can provide for independent verification of bottom-up inventories of fossil fuel CO2 at the regional and national scale. In addition, we show that the dual tracer inversion framework can detect and minimize biases in

  11. Time lag between photosynthesis and CO2 efflux from soil

    NASA Astrophysics Data System (ADS)

    Kuzyakov, Y.; Gavrichkova, O.

    2009-04-01

    Important part of CO2 efflux from planted soils is root-derived CO2, meaning that it originates directly and indirectly from roots: directly from root respiration, and indirectly from respiration of rhizosphere microorganisms decomposing organic substances released by roots into the soil (rhizodeposits). Recent studies have shown that apart of well studied effect of soil temperature and soil water content, the C supply of assimilates from photosynthetically active plant organs have a significant effect on the root-derived CO2. In fact, the effect of photosynthesis on root-derived CO2 is often masked by temperature because root biomass typically peaks in summer. However, roots can only respire the C that was allocated belowground, and so the effect of temperature on root respiration is likely to be constrained by photosynthesis. If models of soil respiration are to incorporate photosynthetic C inputs it is necessary to understand how these two fluxes are coupled and what are the factors affecting the time lag between C uptake and its following respiration by roots and associated microorganisms. We reviewed literature and own studies relevant for estimation of the delay of C assimilation by photosynthesis and CO2 efflux from soil. The most of the studies were based on pulse labeling of annual plants in the atmosphere with 14CO2 or 13CO2 and subsequent chase of 14C or 13C in the CO2 efflux from soil. We analyzed the dynamics of the CO2 efflux curves and evaluated 3 parameters: 1) the first appearance of labeled CO2 from soil, 2) maximum of labeled CO2, and 3) disappearance of the labeled CO2 from the total CO2 efflux from soil. Numerous studies showed that newly assimilated C cycles quickly within the ecosystem, being found in root respiration already some minutes after its assimilation. Reported time lags in situ and laboratory experiments varied from minutes to days. For annual and perennial grasses the first appearance of labeled CO2 from soil was measured within

  12. Comparison of Surface and Column Variations of CO2 Over Urban Areas for Future Active Remote CO2 Sensors

    NASA Technical Reports Server (NTRS)

    Choi, Yonghoon; Yang, Melissa; Kooi, Susan; Browell, Edward

    2015-01-01

    High resolution in-situ CO2 measurements were recorded onboard the NASA P-3B during the DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) Field Campaign, to investigate the ability of space-based observations to accurately assess near surface conditions related to air quality. This campaign includes, Washington DC/Baltimore, MD (July 2011), San Joaquin Valley, CA (January - February 2013), Houston, TX (September 2013), and Denver, CO (July-August 2014). Each of these campaigns consisted of missed approaches and approximately two hundred vertical soundings of CO2 within the lower troposphere (surface to about 5 km). In this study, surface (0 - 1 km) and column-averaged (0 - 3.5 km) CO2 mixing ratio values from the vertical soundings in the four geographically different urban areas are used to investigate the temporal and spatial variability of CO2 within the different urban atmospheric emission environments. Tracers such as CO, CH2O, NOx, and NMHCs are used to identify the source of CO2 variations in the urban sites. Additionally, we apply nominal CO2 column weighting functions for potential future active remote CO2 sensors operating in the 1.57-microns and 2.05-microns measurement regions to convert the in situ CO2 vertical mixing ratio profiles to variations in CO2 column optical depths, which is what the active remote sensors actually measure. Using statistics calculated from the optical depths at each urban site measured during the DISCOVER-AQ field campaign and for each nominal weighting function, we investigate the natural variability of CO2 columns in the lower troposphere; relate the CO2 column variability to the urban surface emissions; and show the measurement requirements for the future ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons) in the continental U.S. urban areas.

  13. Theoretical evidence for inconsistencies in experimental bubble nucleation rates of propane/CO2 and R22/CO2 mixtures

    NASA Astrophysics Data System (ADS)

    Němec, Tomáš

    2015-12-01

    A binary formulation of the classical nucleation theory (CNT) is developed for homogeneous bubble nucleation in systems composed of a liquid solvent and a dissolved gas. The CNT predictions coincide with experimental nucleation data from the literature for diethylether/N2 and isobutane/CO2 mixtures, while several inconsistencies are identified for propane/CO2 and R22/CO2 experimental datasets.

  14. Biofilm enhanced subsurface sequestration of supercritical CO2

    NASA Astrophysics Data System (ADS)

    Mitchell, A. C.; Phillips, A.; Hiebert, R.; Gerlach, R.; Kaszuba, J.; Cunningham, A.

    2007-12-01

    In order to develop subsurface CO2 storage as a viable engineered mechanism to reduce concentrations of atmospheric CO2, any potential ¡°leakage¡± of injected supercritical CO2 (scCO2) from the ground to the atmosphere must be reduced. Here, we investigate the utility of biofilms, which are microorganism assemblages firmly attached to a surface, as a means of reducing scCO2 leakage. Firstly, experiments were performed to test whether biofilms were more resilient than planctonic cells to scCO2. Bacillus mojavensis biofilms were grown on a sand support matrix in scCO2 extractor cartridges at 30°C. B. mojavensis was also grown under suspended planctonic conditions in the same media overnight and aliquots were decanted into scCO2 extractor cartridges. Biofilm and suspended B. mojavensis samples were processed on a Supercritical Fluid Extractor with pressurization to 2000 psi at 35°C, and a 20 minute flow of scCO2. Suspended growth samples revealed a 3 log reduction in cell viability while biofilm only showed a 1 log reduction, demonstrating that B. mojavensis biofilms are more resilient than planctonic cells to scCO2. Protective extra cellular polymeric substances which make up the biofilm matrix likely provide a protective barrier against scCO2. Secondly, the ability of biofilms to grow under high pressure and reduce the permeability of porous geological matrices was investigated using a unique high pressure (8.9MPa), moderate temperature (¡Ý 32°C) flow reactor containing 40 millidarcy Berea sandstone cores. The flow reactor was inoculated with the biofilm forming organism Shewanella fridgidimarina. Electron microscopy of the rock core revealed substantial biofilm accumulation in rock pores which resulted in <99% reduction in core permeability. Permeability did not increase in response to starvation and scCO2 challenges. Viable population assays of organisms in the effluent indicated survival of the microorganisms following scCO2 challenges of <71h and

  15. Seasonal and interannual variations of atmospheric CO2 and climate

    USGS Publications Warehouse

    Dettinger, M.D.; Ghil, M.

    1998-01-01

    Interannual variations of atmospheric CO2 concentrations at Mauna Loa are almost masked by the seasonal cycle and a strong trend; at the South Pole, the seasonal cycle is small and is almost lost in the trend and interannual variations. Singular-spectrum analysis (SSA) issued here to isolate and reconstruct interannual signals at both sites and to visualize recent decadal changes in the amplitude and phase of the seasonal cycle. Analysis of the Mauna Loa CO2 series illustrates a hastening of the CO2 seasonal cycle, a close temporal relation between Northern Hemisphere (NH) mean temperature trends and the amplitude of the seasonal CO2 cycle, and tentative ties between the latter and seasonality changes in temperature over the NH continents. Variations of the seasonal CO2 cycle at the South Pole differ from those at Mauna Loa: it is phase changes of the seasonal cycle at the South Pole, rather than amplitude changes, that parallel hemispheric and global temperature trends. The seasonal CO2 cycles exhibit earlier occurrences of the seasons by 7 days at Mauna Loa and 18 days at the South Pole. Interannual CO2 variations are shared at the two locations, appear to respond to tropical processes, and can be decomposed mostly into two periodicities, around (3 years)-1 and (4 years)-1, respectively. Joint SSA analyses of CO2 concentrations and tropical climate indices isolate a shared mode with a quasi-triennial (QT) period in which the CO2 and sea-surface temperature (SST) participation are in phase opposition. The other shared mode has a quasi-quadrennial (QQ) period and CO2 variations are in phase with the corresponding tropical SST variations throughout the tropics. Together these interannual modes exhibit a mean lag between tropical SSTs and CO2 variations of about 6-8 months, with SST leading. Analysis of the QT and QQ signals in global gridded SSTs, joint SSA of CO2 and ??13C isotopic ratios, and SSA of CO2 and NH-land temperatures indicate that the QT variations in

  16. Enhancing the Ocean's Role in CO2 Mitigation

    NASA Astrophysics Data System (ADS)

    Rau, G. H.

    2012-12-01

    The possibility of safely increasing the ocean's significant, natural consumption and storage of excess CO2 deserves consideration since land-based efforts are thus far failing to stabilize atmospheric CO2 and associated climate and ocean chemistry impacts. Of the approximately 34 GT/yr of CO2 currently emitted to the atmosphere by human activity, the ocean consumes the equivalent of about 8 GT/yr of these emissions. These fluxes are, however, dwarfed by the annual gross amount of CO2 naturally taken up and released by the ocean, in excess of 300 GT CO2/yr. Additionally, the carbon content in the ocean is about 50 times that of the atmosphere, with the majority in a form (HCO2-) that can, through equilibrium reactions, interact with atmospheric CO2. Marine chemical, biological and physical processes that naturally affect ocean CO2 gain and loss thus intimately influence the natural carbon content of the atmosphere. Indeed, ocean chemistry in conjunction with carbonate and silicate mineral weathering is the primary mechanism that naturally moderates and consumes excess atmospheric CO2 on geologic timescales. The ocean is therefore a logical place to explore means of enhancing atmospheric and anthropogenic carbon uptake and/or sequestration in efforts to stabilize or possibly reduce atmospheric CO2 concentrations. Modification of such global processes (often only relatively slightly) forms the basis for many of the ocean-based CO2 mitigation approaches thus far proposed. These include: 1) the storage in or under the ocean of molecular CO2, or organic or inorganic derivatives that have been captured or formed on land; 2) the removal of ocean/atmosphere CO2 via biological uptake enhanced by artificially increased upwelling or nutrient addition; 3) the chemical, geochemical, or electrochemical alkalization of the ocean to increase ocean CO2 uptake with chemical transformation to bicarbonates or carbonates, and subsequent ocean storage; and 4) increased production and

  17. CO2 Emissions Measurements at Kilauea Volcano, Hawaii USA

    NASA Astrophysics Data System (ADS)

    Sutton, A. J.; Elias, T.

    2012-12-01

    The importance of volcanic CO2 release in Hawaii has been recognized for at least 100 years. The early gas collections of Jaggar, Shepherd, and Day showed that CO2 was the second most prevalent gas, next to water, in Kilauea's eruptive emissions. As one of Earth's few long-lived, effusive eruptions that have been closely monitored, Kilauea's measured CO2 emissions have served as a global benchmark. At Kilauea in the mid-1980's, conventional airborne, in-plume profiling measurements of CO2 underestimated emissions, due to plume geometry. Remotely-Piloted Aircraft (RPA) and vehicle-based measurements made a decade later showed that at Kilauea, CO2 concentrations were highest near ground level. Methods for quantifying emission rates of CO2 have since been improved via vehicle-based measurements of the ground-hugging plume. Gerlach and others, 2002, used the integrated CO2/SO2 molecular ratio and SO2 emission rate to derive the CO2 emission rate. Their results established a long-term characteristic CO2 emission rate for the summit of Kilauea of 8,500 t/d. This rate was based on several nearly equal measurements spanning a 4 year period, along with an independently reported, steady magma supply rate. Gerlach and others (1998) estimated a contemporaneous east rift CO2 emission rate of 300 t/d. From 2004 to mid-2007, summit CO2 emissions from Kilauea increased twofold on average, and then declined as a surge in magma supply eventually resulted in the forceful opening of a new vent within Halema`uma`u crater at Kilauea's summit in 2008. The elevated summit activity has provided opportunities to test other methods for measuring CO2 abundance in Kilauea's poorly mixed summit plume. Closed space continuous CO2 concentration monitoring within a subsurface vault, recorded transient (minutes-to-days) ambient fluctuations of thousands of parts per million, atop an overall slowly-varying (weeks to months) increase that led up to the 2008 summit eruption. Fumarole gas molecular CO2

  18. Chemical reactions occurring during direct solar reduction of CO2.

    PubMed

    Lyma, J L; Jensen, R J

    2001-09-28

    At high temperatures carbon dioxide may absorb solar radiation and react to form carbon monoxide and molecular oxygen. The CO, so produced, may be converted by well-established means to a combustible fuel, such as methanol. We intend to make a future demonstration of the solar reduction of CO2 based on these processes. This paper, however, addresses only the problem of preserving, or even enhancing, the initial photolytic CO by quenching the hot gas with colder H2O or CO2. We present model calculations with a reaction mechanism used extensively in other calculations. If a CO2 gas stream is heated and photolyzed by intense solar radiation and then allowed to cool slowly, it will react back to the initial CO2 by a series of elementary chemical reactions. The back reaction to CO2 can be terminated with the rapid addition of CO2, water, or a mixture. Calculations show that a three-fold quench with pure CO2 will stop the reactions and preserve over 90% of the initial photolytic CO. We find that water has one of two effects. It can either increase the CO level, or it can catalyze the recombination of O and CO to CO2. The gas temperature is the determining factor. If the quench gas is not sufficient to keep the temperature below approximately 1100 K, a chain-branching reaction dominates and the reaction to CO2 occurs. If the temperature stays below that level a chain terminating reaction dominates and the CO is increased. The former case occurs below approximately a fourfold quench with a water/CO2 mixture. The later case occurs when the quench is greater than fourfold. We conclude that CO2, H2O, or a mixture may quench the hot gas stream photolyzed by solar radiation and preserve the photolytic CO. PMID:11589409

  19. Uncertainty Quantification for CO2-Enhanced Oil Recovery

    NASA Astrophysics Data System (ADS)

    Dai, Z.; Middleton, R.; Bauman, J.; Viswanathan, H.; Fessenden-Rahn, J.; Pawar, R.; Lee, S.

    2013-12-01

    CO2-Enhanced Oil Recovery (EOR) is currently an option for permanently sequestering CO2 in oil reservoirs while increasing oil/gas productions economically. In this study we have developed a framework for understanding CO2 storage potential within an EOR-sequestration environment at the Farnsworth Unit of the Anadarko Basin in northern Texas. By coupling a EOR tool--SENSOR (CEI, 2011) with a uncertainty quantification tool PSUADE (Tong, 2011), we conduct an integrated Monte Carlo simulation of water, oil/gas components and CO2 flow and reactive transport in the heterogeneous Morrow formation to identify the key controlling processes and optimal parameters for CO2 sequestration and EOR. A global sensitivity and response surface analysis are conducted with PSUADE to build numerically the relationship among CO2 injectivity, oil/gas production, reservoir parameters and distance between injection and production wells. The results indicate that the reservoir permeability and porosity are the key parameters to control the CO2 injection, oil and gas (CH4) recovery rates. The distance between the injection and production wells has large impact on oil and gas recovery and net CO2 injection rates. The CO2 injectivity increases with the increasing reservoir permeability and porosity. The distance between injection and production wells is the key parameter for designing an EOR pattern (such as a five (or nine)-spot pattern). The optimal distance for a five-spot-pattern EOR in this site is estimated from the response surface analysis to be around 400 meters. Next, we are building the machinery into our risk assessment framework CO2-PENS to utilize these response surfaces and evaluate the operation risk for CO2 sequestration and EOR at this site.

  20. Buoyancy-driven CO2/brine flow at reservoir conditions

    NASA Astrophysics Data System (ADS)

    Oh, J.; Kim, K.; Han, W.; Kim, T.; Kim, J.; Park, E.

    2013-12-01

    Suitable geological formations should guarantee a long-term safe and reliable storage of the injected supercritical CO2. In this study we targeted the cases of gravity-driven CO2 plume migration in a storage formation and the resulting CO2 leakage to overlying formation through a possible fractures or abandoned wells. A laboratory experiment and numerical model for two-phase core-flooding tests were designed to understand the buoyancy effect on supercritical CO2 migration under reservoir conditions. A series of core flooding tests were performed with Berea sandstone cores which have 20 % porosity and 1.7×10-13 m2 permeability. Unlike the normal core-flooding tests, the core was set up in a vertical direction and the CO2 was released at the bottom of the core to investigate the gravity effect on CO2 migration. During the test, the downstream pressure was maintained at 10 MPa, and the confining pressure was kept at 20 MPa. The temperature was set to be 40 °C to reflect the 1 km subsurface environment. The CO2-flooding (drainage) tests with brine-saturated core were performed with various CO2-release periods. The CO2 saturation was measured with a linear X-ray scanner. In addition to laboratory experiments, numerical simulations were performed to provide further insight into the CO2 migration behavior. TOUGH2 with ECO2N module was used to simulate CO2/brine core-flooding tests. Dimensionless numbers (Capillary number and Bond number) were calculated with the simulation results at various time points covering both the release and monitoring period.

  1. Well Integrity and Sealing in CO2 Sequestration Wells

    NASA Astrophysics Data System (ADS)

    Sweatman, R.; Santra, A.; Kulakofsky, D.

    2009-12-01

    CO2 sequestration is a cost-effective and safe way to help mitigate climate change. Sustained well integrity and zonal isolation of CO2 by cement for the required 1000 year trapping period may be challenging. Some researchers report that cement fails when exposed to CO2 leading to potential leakage into the atmosphere or other underground zones. Others show cement samples from 30-50 year old CO2 wells that maintain the well’s sealing integrity, even though carbonization was found. This presentation provides reasons likely for this disparity between research lab test results and actual well performance data along with best practices to provide efficient cement-based systems for maintaining CO2 containment in storage and EOR (enhanced oil recovery) reservoirs. This discussion includes the geochemical conditions surrounding wells and the positive, long-term effects on cement durability, sealing integrity, and the protection of well casing from CO2 induced corrosion. Also discussed are recent laboratory results testing cement samples surrounded by formation material treated at two different downhole conditions. In one case the cement specimens were treated with a 40% humid CO2 at 140°F and 2000 psi whereas in the second case they were treated with saturated CO2 in water at 200°F and 2000 psi for various time intervals. Results show that samples of carefully designed cement systems had carbonization without any sign of loss of mechanical or sealing integrity which could lead to zonal isolation and well integrity failures. We also will report on a new lab method proposed to determine CO2 sealing performance by cement in a relatively short time period compared to previous methods. In summary, we will discuss a comprehensive approach that may be taken to help ensure longer term effective well integrity and CO2 containment in new CO2 wells and remedial solutions for old wells and for plugging and abandoning wells.

  2. Distribution and nature of CO2 on Enceladus

    NASA Astrophysics Data System (ADS)

    Combe, J. P.; McCord, T. B.; Matson, D.; Johnson, T. V.; Scipioni, F.; Tosi, F.

    2015-12-01

    We present the first global mapping and analysis of CO2 on the surface of Enceladus, and we report the largest concentrations of free CO2 on the southern polar region using the Visual and Infrared Mapping Spectrometer (VIMS) on Cassini. Free CO2 ice and complexed CO2 were already reported near the South Pole (Brown et al., Science, 2006; Hansen, LPSC, 2010). Our work focuses on determining the amount, location and molecular state of CO2 on Enceladus, which could help identify and model geophysical processes that currently occur in the interior. One hypothesis for bringing heat and chemicals to the surface is a warm subsurface ocean containing dissolved gases, mostly CO2 (Postberg F. et al., Nature, 2009). Therefore, our observations are consistent with erupted and condensed materials onto Enceladus' surface (Matson et al., Icarus, 2012; Matson et al. AGU Fall meeting 2015). Free CO2 ice absorbs at 4.268 µm (Sandford and Allamandola, 1990) and CO2 complexed with other molecules absorbs at 4.247 μm (Chaban et al., Icarus, 2007). The Enceladus case is complicated because both free and complexed CO2 are present, and the absorption band of interest is shallow and close to the instrument detection limit. Many of the few Enceladus VIMS data sets have significant and sometimes unusual noise, which we attempted to avoid or remove. We utilized all VIMS data sets available that were collected over ten years of the Cassini mission as a way to improve the detection statistics and signal to noise. We also used wavelengths near 2.7 μm where CO2 has a narrow absorption as a filter to help identify CO2-rich areas. Finally, we selected observations that have spatial resolution better than 100 km in order to create a map that can be compared with the largest fractures, known as Tiger Stripes, in the southern polar region.

  3. 5% CO2 is a potent, fast acting inhalation anticonvulsant

    PubMed Central

    Tolner, Else A.; Hochman, Daryl W.; Hassinen, Pekka; Otáhal, Jakub; Gaily, Eija; Haglund, Michael M.; Kubová, Hana; Schuchmann, Sebastian; Vanhatalo, Sampsa; Kaila, Kai

    2010-01-01

    Purpose CO2 has been long recognized for its anticonvulsant properties. We aimed to determine whether inhaling 5% CO2 can be used to suppress seizures in epilepsy patients. The effect of CO2 on cortical epileptic activity accompanying behavioral seizures was studied in rats and a non-human primate and based on these data, preliminary tests were carried out in humans. Methods In freely moving rats, cortical afterdischarges paralleled by myoclonic convulsions were evoked by sensorimotor cortex stimulation. 5% CO2 was applied for 5 minutes, 3 minutes before stimulation. In macaque monkeys, hypercarbia was induced by hypoventilation while seizure activity was electrically or chemically evoked in the sensorimotor cortex. Seven patients with drug-resistant partial epilepsy were examined with video-EEG and received 5% CO2 in medical carbogen shortly after electrographic seizure onset. Results In rats, 5% CO2 strongly suppressed cortical afterdischarges, by ca. 75%, while responses to single-pulse stimulation were reduced by about 15% only. In macaques, increasing pCO2 from 37 to 44-45 mmHg (corresponding to inhalation of 5% CO2 or less) suppressed stimulation-induced cortical afterdischarges by about 70% and single, bicuculline-induced epileptiform spikes by ca. 25%. In a pilot trial carried out in 7 patients, a rapid termination of electrographic seizures was seen despite the fact that the application of 5% CO2 was started after seizure generalization. Conclusions 5% CO2 has a fast and potent anticonvulsant action. The present data suggest that medical carbogen with 5% CO2 can be used for acute treatment to suppress seizures in epilepsy patients. PMID:20887367

  4. Using Subsurface CO2 Concentrations and Isotopologues to Identify CO2 Seepage from CCS/CO2-EOR Projects: A Signal-to-Noise Based Analysis

    NASA Astrophysics Data System (ADS)

    Nickerson, N. R.; Risk, D. A.

    2012-12-01

    In order to fulfill a role in demonstrating containment, surface monitoring for Carbon Capture and Geologic Storage (CCS) sites must be able to clearly discriminate between natural, and leakage-source CO2. The CCS community lacks a clear metric for quantifying the degree of discrimination, for successful inter-comparison of monitoring approaches. This study illustrates the utility of Signal-to-Noise Ratio (SNR) to compare the relative performance of three commonly used soil gas monitoring approaches, including bulk CO2, δ13CO2, and Δ14CO2. For inter-comparisons, we used a simulated northern temperate landscape similar to that of Weyburn, Saskatchewan (home of the IEAGHG Weyburn-Midale CO2 Monitoring and Storage Project), in which realistic spatial and temporal CO2 and isotopic variation is simulated for periods of one year or more. Results indicate, that, for this particular ecosystem, Δ14C signatures have the best overall SNR at all simulated seepage rates, and for all points across the synthetic landscape. We then apply this same SNR based approach to data collected during a 6-month sampling campaign at three locations on the Weyburn oil field. This study emphasizes both the importance of developing clear metrics for monitoring performance, and the benefit of modeling for decision support in CCS monitoring design.

  5. Responses of Arabidopsis and Wheat to Rising CO2 Depend on Nitrogen Source and Nighttime CO2 Levels1[OPEN

    PubMed Central

    Rachmilevitch, Shimon

    2015-01-01

    A major contributor to the global carbon cycle is plant respiration. Elevated atmospheric CO2 concentrations may either accelerate or decelerate plant respiration for reasons that have been uncertain. We recently established that elevated CO2 during the daytime decreases plant mitochondrial respiration in the light and protein concentration because CO2 slows the daytime conversion of nitrate (NO3−) into protein. This derives in part from the inhibitory effect of CO2 on photorespiration and the dependence of shoot NO3− assimilation on photorespiration. Elevated CO2 also inhibits the translocation of nitrite into the chloroplast, a response that influences shoot NO3− assimilation during both day and night. Here, we exposed Arabidopsis (Arabidopsis thaliana) and wheat (Triticum aestivum) plants to daytime or nighttime elevated CO2 and supplied them with NO3− or ammonium as a sole nitrogen (N) source. Six independent measures (plant biomass, shoot NO3−, shoot organic N, 15N isotope fractionation, 15NO3− assimilation, and the ratio of shoot CO2 evolution to O2 consumption) indicated that elevated CO2 at night slowed NO3− assimilation and thus decreased dark respiration in the plants reliant on NO3−. These results provide a straightforward explanation for the diverse responses of plants to elevated CO2 at night and suggest that soil N source will have an increasing influence on the capacity of plants to mitigate human greenhouse gas emissions. PMID:25755253

  6. Responses of Arabidopsis and wheat to rising CO2 depend on nitrogen source and nighttime CO2 levels.

    PubMed

    Asensio, Jose Salvador Rubio; Rachmilevitch, Shimon; Bloom, Arnold J

    2015-05-01

    A major contributor to the global carbon cycle is plant respiration. Elevated atmospheric CO2 concentrations may either accelerate or decelerate plant respiration for reasons that have been uncertain. We recently established that elevated CO2 during the daytime decreases plant mitochondrial respiration in the light and protein concentration because CO2 slows the daytime conversion of nitrate (NO3 (-)) into protein. This derives in part from the inhibitory effect of CO2 on photorespiration and the dependence of shoot NO3 (-) assimilation on photorespiration. Elevated CO2 also inhibits the translocation of nitrite into the chloroplast, a response that influences shoot NO3 (-) assimilation during both day and night. Here, we exposed Arabidopsis (Arabidopsis thaliana) and wheat (Triticum aestivum) plants to daytime or nighttime elevated CO2 and supplied them with NO3 (-) or ammonium as a sole nitrogen (N) source. Six independent measures (plant biomass, shoot NO3 (-), shoot organic N, (15)N isotope fractionation, (15)NO3 (-) assimilation, and the ratio of shoot CO2 evolution to O2 consumption) indicated that elevated CO2 at night slowed NO3 (-) assimilation and thus decreased dark respiration in the plants reliant on NO3 (-). These results provide a straightforward explanation for the diverse responses of plants to elevated CO2 at night and suggest that soil N source will have an increasing influence on the capacity of plants to mitigate human greenhouse gas emissions. PMID:25755253

  7. CO2 Efflux from Shrimp Ponds in Indonesia

    PubMed Central

    Sidik, Frida; Lovelock, Catherine E.

    2013-01-01

    The conversion of mangrove forest to aquaculture ponds has been increasing in recent decades. One of major concerns of this habitat loss is the release of stored ‘blue’ carbon from mangrove soils to the atmosphere. In this study, we assessed carbon dioxide (CO2) efflux from soil in intensive shrimp ponds in Bali, Indonesia. We measured CO2 efflux from the floors and walls of shrimp ponds. Rates of CO2 efflux within shrimp ponds were 4.37 kg CO2 m−2 y−1 from the walls and 1.60 kg CO2 m−2 y−1 from the floors. Combining our findings with published data of aquaculture land use in Indonesia, we estimated that shrimp ponds in this region result in CO2 emissions to the atmosphere between 5.76 and 13.95 Tg y−1. The results indicate that conversion of mangrove forests to aquaculture ponds contributes to greenhouse gas emissions that are comparable to peat forest conversion to other land uses in Indonesia. Higher magnitudes of CO2 emission may be released to atmosphere where ponds are constructed in newly cleared mangrove forests. This study indicates the need for incentives that can meet the target of aquaculture industry without expanding the converted mangrove areas, which will lead to increased CO2 released to atmosphere. PMID:23755306

  8. Oxidation in Environments with Elevated CO2 Levels

    SciTech Connect

    Gordon H. Holcomb

    2009-05-01

    Efforts to reduce greenhouse gas emissions from fossil energy power productions focus primarily on either pre- or post-combustion removal of CO2. The research presented here examines corrosion and oxidation issues associated with two types of post-combustion CO2 removal processes—oxyfuel combustion in refit boilers and oxyfuel turbines.

  9. Growth and control of invasive weeds under elevated CO2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atmospheric concentrations of CO2 have been increasing since the onset of the industrial revolution. Regardless of the debate on the effects of this rise on climate, most plants exhibit a positive growth response to elevated CO2 due to increased photosynthesis, resource use efficiency, and/or alloca...

  10. Multiple timescales for neutralization of fossil fuel CO2

    NASA Astrophysics Data System (ADS)

    Archer, David; Kheshgi, Haroon; Maier-Reimer, Ernst

    The long term abiological sinks for anthropogenic CO2 will be dissolution in the oceans and chemical neutralization by reaction with carbonates and basic igneous rocks. We use a detailed ocean/sediment carbon cycle model to simulate the response of the carbonate cycle in the ocean to a range of anthropogenic CO2 release scenarios. CaCO3 will play only a secondary role in buffering the CO2 concentration of the atmosphere because CaCO3 reaction uptake capacity and kinetics are limited by the dynamics of the ocean carbon cycle. Dissolution into ocean water sequesters 70-80% of the CO2 release on a time scale of several hundred years. Chemical neutralization of CO2 by reaction with CaCO3 on the sea floor accounts for another 9-15% decrease in the atmospheric concentration on a time scale of 5.5-6.8 kyr. Reaction with CaCO3 on land accounts for another 3-8%, with a time scale of 8.2 kyr. The final equilibrium with CaCO3 leaves 7.5-8% of the CO2 release remaining in the atmosphere. The carbonate chemistry of the oceans in contact with CaCO3 will act to buffer atmospheric CO2 at this higher concentration until the entire fossil fuel CO2 release is consumed by weathering of basic igneous rocks on a time scale of 200 kyr.

  11. CO2 rebreathing during BiPAP ventilatory assistance.

    PubMed

    Ferguson, G T; Gilmartin, M

    1995-04-01

    BiPAP ventilatory assistance can increase minute ventilation and reduce respiratory effort, but does not always reduce PaCO2. We studied the effects of BiPAP ventilatory assistance on PaCO2 and examined specific mechanisms whereby BiPAP ventilatory assistance may not lower PaCO2. BiPAP ventilatory assistance using a non-rebreather valve and volume cycled ventilation at similar settings produced significantly lower PaCO2 than BiPAP ventilatory assistance using a standard exhalation device. The failure of PaCO2 to fall with the standard exhalation device was due to exhalation past the exhalation device into the ventilator tubing, subsequent rebreathing of the exhaled gases, and an increase in dead space ventilation. Use of other fixed-resistance exhalation devices also resulted in exhalation back into the ventilator tubing. Use of a new plateau exhalation device or a non-rebreather valve eliminated CO2 rebreathing and its effect on dead space ventilation. Changing exhalation devices had no significant effect on BiPAP pressure generation or sensing capabilities. Our results indicate that the use of a standard exhalation device during BiPAP ventilatory assistance causes CO2 rebreathing, which can blunt any effect of BiPAP on PaCO2. Use of an appropriate alternative exhalation device can eliminate this problem. PMID:7697242

  12. The unstable CO2 feedback cycle on ocean planets

    NASA Astrophysics Data System (ADS)

    Kitzmann, D.; Alibert, Y.; Godolt, M.; Grenfell, J. L.; Heng, K.; Patzer, A. B. C.; Rauer, H.; Stracke, B.; von Paris, P.

    2015-10-01

    Ocean planets are volatile-rich planets, not present in our Solar system, which are thought to be dominated by deep, global oceans. This results in the formation of high-pressure water ice, separating the planetary crust from the liquid ocean and, thus, also from the atmosphere. Therefore, instead of a carbonate-silicate cycle like on the Earth, the atmospheric carbon dioxide concentration is governed by the capability of the ocean to dissolve carbon dioxide (CO2). In our study, we focus on the CO2 cycle between the atmosphere and the ocean which determines the atmospheric CO2 content. The atmospheric amount of CO2 is a fundamental quantity for assessing the potential habitability of the planet's surface because of its strong greenhouse effect, which determines the planetary surface temperature to a large degree. In contrast to the stabilizing carbonate-silicate cycle regulating the long-term CO2 inventory of the Earth atmosphere, we find that the CO2 cycle feedback on ocean planets is negative and has strong destabilizing effects on the planetary climate. By using a chemistry model for oceanic CO2 dissolution and an atmospheric model for exoplanets, we show that the CO2 feedback cycle can severely limit the extension of the habitable zone for ocean planets.

  13. Textile dry cleaning in high pressure CO2

    NASA Astrophysics Data System (ADS)

    Sutanto, Stevia; van der Kamp, Maaike; Witkamp, Geert-Jan

    2013-06-01

    High-pressure carbon dioxide (CO2) is one of the most suitable replacements for perchloroethylene (PER), a common but harmful textile dry cleaning solvent. Previous studies have indicated that the particulate soil removal with CO2 is lower compared to that with PER, because of the lesser amount of mechanical action in CO2. Furthermore, there is a lack of understanding of textile-dirt-CO2 interaction. It is the objective of this study to get an insight in the mechanical forces that play a role in CO2 dry cleaning and to use this information to improve the CO2 washing performance. Various mechanical actions were investigated with the experiments in an in-situ high pressure observation cell. Textiles stained with different kinds of particulate soils were washed in CO2. The washing results show that the combination of rotating and vertical action gives the highest cleaning performance and liquid CO2 spray may be a suitable additional mechanism to increase the cleaning performance. Authors thank the scientific foundation STW for the financial support.

  14. Biogeophysical effects of CO2 fertilization on global climate

    NASA Astrophysics Data System (ADS)

    Bala, G.; Caldeira, K.; Mirin, A.; Wickett, M.; Delire, C.; Phillips, T. J.

    2006-11-01

    CO2 fertilization affects plant growth, which modifies surface physical properties, altering the surface albedo, and fluxes of sensible and latent heat. We investigate how such CO2-fertilization effects on vegetation and surface properties would affect the climate system. Using a global three-dimensional climate-carbon model that simulates vegetation dynamics, we compare two multicentury simulations: a `Control' simulation with no emissions and a `Physiol-noGHG' simulation where physiological changes occur as a result of prescribed CO2 emissions, but where CO2-induced greenhouse warming is not included. In our simulations, CO2 fertilization produces warming; we obtain an annual- and global-mean warming of about 0.65 K (and land-only warming of 1.4 K) after 430 yr. This century-scale warming is mostly due to a decreased surface albedo associated with the expansion of the Northern Hemisphere boreal forests. On decadal timescales, the CO2 uptake by afforestation should produce a cooling effect that exceeds this albedo-based warming; but if the forests remain in place, the CO2-enhanced-greenhouse effect would diminish as the ocean equilibrates with the atmosphere, whereas the albedo effect would persist. Thus, on century timescales, there is the prospect for net warming from CO2 fertilization of the land biosphere. Further study is needed to confirm and better quantify our results.

  15. Effects of CO2 Physiological Forcing on Amazon Climate

    NASA Astrophysics Data System (ADS)

    Halladay, K.; Good, P.; Kay, G.; Betts, R.

    2014-12-01

    Earth system models provide us with an opportunity to examine the complex interactions and feedbacks between land surface, vegetation and atmosphere. A more thorough understanding of these interactions is essential in reducing uncertainty surrounding the potential impacts of climate and environmental change on the future state and extent of the Amazon rainforest. This forest is a important resource for the region and globally in terms of ecosystem services, hydrology and biodiversity. We aim to investigate the effect of CO2 physiological forcing on the Amazon rainforest and its feedback on regional climate by using the CMIP5 idealised 1% CO2 simulations with a focus on HadGEM2-ES. In these simulations, the atmospheric CO2 concentration is increased by 1% per year for 140 years, reaching around 1150ppm at the end of the simulation. The use of idealised simulations allows the effect of CO2 to be separated from other forcings and the sensitivities to be quantified. In particular, it enables non-linear feedbacks to be identified. In addition to the fully coupled 1% CO2 simulation, in which all schemes respond to the forcing, we use simulations in which (a) only the biochemistry scheme sees the rising CO2 concentration, and (b) in which rising CO2 is only seen by the radiation scheme. With these simulations we examine the degree to which CO2 effects are additive or non-linear when in combination. We also show regional differences in climate and vegetation response, highlighting areas of increased sensitivity.

  16. Elevated CO2 Effects on Mercury Content of Forest Soils

    NASA Astrophysics Data System (ADS)

    Natali, S. M.; Lerdau, M.; Sañudo-Wilhelmy, S. A.

    2006-12-01

    Fossil fuel combustion is the primary anthropogenic source of both CO2 and mercury (Hg) to the atmosphere. Terrestrial vegetation can act as a conduit for transferring atmospheric Hg into soils and freshwater systems. While the effects of CO2 on both terrestrial plants and soils have been well-studied, the impacts of these CO2 induced changes on Hg cycling are unknown. We found that elevated CO2 resulted in increased Hg concentration in forest soils. Soil Hg concentration in the top 20cm of soils was 26% greater and total Hg content was 22% greater under elevated CO2 (ambient + 200ppmv), relative to ambient at two FACE sites: Duke Forest, NC and Oak Ridge, TN. However, there was no significant CO2 effect on Hg inputs via leaf litter. Soil Hg was significantly correlated with soil organic matter and acidity, suggesting that CO2 mediated changes in soil properties may be affecting soil Hg content. Elevated atmospheric CO2 has the potential to increase the Hg trapping efficiency of soils, with still unknown effects on terrestrial and aquatic ecosystem function.

  17. 46 CFR 108.451 - CO2 storage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false CO2 storage. 108.451 Section 108.451 Shipping COAST... Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.451 CO2 storage. (a... have one or more cylinders in the space protected by the system if the space has a heat...

  18. 46 CFR 108.451 - CO2 storage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false CO2 storage. 108.451 Section 108.451 Shipping COAST... Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.451 CO2 storage. (a... have one or more cylinders in the space protected by the system if the space has a heat...

  19. 46 CFR 108.451 - CO2 storage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false CO2 storage. 108.451 Section 108.451 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.451 CO2 storage. (a) Except as provided in paragraph (b) of...

  20. Remote sensing of chemical warfare agent by CO2 -lidar

    NASA Astrophysics Data System (ADS)

    Geiko, Pavel P.; Smirnov, Sergey S.

    2014-11-01

    The possibilities of remote sensing of chemical warfare agent by differential absorption method were analyzed. The CO2 - laser emission lines suitable for sounding of chemical warfare agent with provision for disturbing absorptions by water vapor were choose. The detection range of chemical warfare agents was estimated for a lidar based on CO2 - laser The other factors influencing upon echolocation range were analyzed.

  1. Blackbody pumped N2-CO2 transfer laser

    NASA Astrophysics Data System (ADS)

    de Young, R. J.

    1984-06-01

    The power and intrinsic efficiency of a small N2-CO2 fluid mixing transfer laser has been measured. Powers of 1.4 watts and intrinsic efficiencies for 0.7 percent were found for N2 oven temperatures of 1473 K. Laser output was optimized for He, CO2 and N2 partial pressures, output mirror reflectivity, nozzle diameter and oven temperature.

  2. 40 CFR 98.423 - Calculating CO2 supply.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Calculating CO2 supply. 98.423 Section 98.423 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Carbon Dioxide § 98.423 Calculating CO2 supply. (a)...

  3. 46 CFR 108.451 - CO2 storage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false CO2 storage. 108.451 Section 108.451 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.451 CO2 storage....

  4. 40 CFR 98.423 - Calculating CO2 supply.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Calculating CO2 supply. 98.423 Section 98.423 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Carbon Dioxide § 98.423 Calculating CO2 supply. (a)...

  5. 46 CFR 108.451 - CO2 storage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false CO2 storage. 108.451 Section 108.451 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.451 CO2 storage. (a) Except as provided in paragraph (b) of...

  6. Effect of heterogeneousatmospheric CO2 on simulated global carbon budget

    USGS Publications Warehouse

    Zhang, Zhen; Jiang, Hong; Liu, Jinxun; Ju, Weimin; Zhang, Xiuying

    2013-01-01

    The effects of rising atmospheric carbon dioxide (CO2) on terrestrial carbon (C) sequestration have been a key focus in global change studies. As anthropological CO2 emissions substantially increase, the spatial variability of atmospheric CO2 should be considered to reduce the potential bias on C source and sink estimations. In this study, the global spatial–temporal patterns of near surface CO2 concentrations for the period 2003-2009 were established using the SCIAMACHY satellite observations and the GLOBALVIEW-CO2 field observations. With this CO2 data and the Integrated Biosphere Simulator (IBIS), our estimation of the global mean annual NPP and NEP was 0.5% and 7% respectively which differs from the traditional C sequestration assessments. The Amazon, Southeast Asia, and Tropical Africa showed higher C sequestration than the traditional assessment, and the rest of the areas around the world showed slightly lower C sequestration than the traditional assessment. We find that the variability of NEP is less intense under heterogeneous CO2 pattern on a global scale. Further studies of the cause of CO2 variation and the interactions between natural and anthropogenic processes of C sequestration are needed.

  7. Fabrication of a glycerol from CO2 reaction system, supplement

    NASA Technical Reports Server (NTRS)

    Weiss, A. H.

    1973-01-01

    The fabrication, installation, and testing of a glycerol hydrogenation and a CO2 hydrogenation - CH4 partial oxidation units are reported. The glycerol system proved to be operational while the CO2 system was installed but not bought on operational steam.

  8. CO 2-laser photoacoustic detection of gaseous n-pentylacetate

    NASA Astrophysics Data System (ADS)

    Herecová, Lenka; Hejzlar, Tomáš; Pavlovský, Jiří; Míček, Dalibor; Zelinger, Zdeněk; Kubát, Pavel; Janečková, Radmila; Nevrlý, Václav; Bitala, Petr; Střižík, Michal; Klouda, Karel; Civiš, Svatopluk

    2009-07-01

    The absorption spectra of gaseous n-pentylacetate were investigated by FT IR spectroscopy as well as CO 2-laser photoacoustic spectroscopy for simulation of the dispersion of a nerve agent (sarin) within a modeled atmospheric boundary layer. Three CO 2-laser emission lines were used for photoacoustic detection of n-pentylacetate with detection limit in the range of 1-3 ppm.

  9. On the losses of dissolved CO(2) during champagne serving.

    PubMed

    Liger-Belair, Gérard; Bourget, Marielle; Villaume, Sandra; Jeandet, Philippe; Pron, Hervé; Polidori, Guillaume

    2010-08-11

    Pouring champagne into a glass is far from being consequenceless with regard to its dissolved CO(2) concentration. Measurements of losses of dissolved CO(2) during champagne serving were done from a bottled Champagne wine initially holding 11.4 +/- 0.1 g L(-1) of dissolved CO(2). Measurements were done at three champagne temperatures (i.e., 4, 12, and 18 degrees C) and for two different ways of serving (i.e., a champagne-like and a beer-like way of serving). The beer-like way of serving champagne was found to impact its concentration of dissolved CO(2) significantly less. Moreover, the higher the champagne temperature is, the higher its loss of dissolved CO(2) during the pouring process, which finally constitutes the first analytical proof that low temperatures prolong the drink's chill and helps it to retain its effervescence during the pouring process. The diffusion coefficient of CO(2) molecules in champagne and champagne viscosity (both strongly temperature-dependent) are suspected to be the two main parameters responsible for such differences. Besides, a recently developed dynamic-tracking technique using IR thermography was also used in order to visualize the cloud of gaseous CO(2) which flows down from champagne during the pouring process, thus visually confirming the strong influence of champagne temperature on its loss of dissolved CO(2). PMID:20681665

  10. Comparison of CO2 Photoreduction Systems: A Review

    EPA Science Inventory

    Carbon dioxide (CO2) emissions are a major contributor to the climate change equation. To alleviate concerns of global warming, strategies to mitigate increase of CO2 levels in the atmosphere have to be developed. The most desirable approach is to convert the carbon dioxide to us...

  11. Some sources of variability in the CO2 enhancement ratio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent meta-analyses and compilations of past experiments show a wide range of crop productivity responses to elevated atmospheric [CO2]. Variances, even within the same protocols, can be quite large ranging from less than 1 to greater than 30 times for [CO2] about double the current atmospheric mea...

  12. CO2/brine migrations in a laterally closed reservoir system

    NASA Astrophysics Data System (ADS)

    Kim, K.; Han, W.; Lee, P.

    2013-12-01

    Geologic CO2 storage is considered as a promising solution for the mitigation of global CO2 emission levels. In assessing pressure and/or CO2 saturation distribution in a reservoir scale system, many studies have assumed that geologic formations consist of impermeable upper and lower boundaries to both supercritical CO2 and brine, and laterally open system. Under these conditions, the primary direction of brine flow is horizontal, as CO2 displaces the brine. However, in certain geologic situations, storage formation may laterally be compartmented due to presence of low-permeability zones creating a closed system. In this study we intended to assess the CO2/brine fluxes between the targeted storage formation and the upper and lower seals in a laterally closed reservoir system. The simulations were conducted using TOUGH2 with ECO2N module. A hypothetical two-dimensional radial model was designed to assess the spatial distribution of pressure build-up and the supercritical CO2 plume over time in a laterally closed system. The storage formation of 100 m thickness is radially extended to 10,000m and is located at 1,000 m below from the ground surface bounded by overlying and underlying seals of 100 m thickness. The CO2 injection rate was set to be 30 kg/s and the life-time of this hypothetical project was 30 years (10 years of injection followed by 20 years of monitoring period). The simulation results showed distinct CO2/brine flow regimes at three different zones; the dry-out zone, the two-phase zone, and the brine zone. At the dry-out zone, the direction of CO2 flux was from the storage formation toward the overlying and underlying seals while the brine flux was from the over- and underlying seals toward the storage formation. The CO2 and brine fluxes per unit area showed respectively up to 6×10-5 kg/s/m2 and 1×10-4 kg/s/m2 during the injection period, and decreased after injection ceased. At the two-phase zone, the CO2/brine migration was similar to that at dry

  13. Natural CO2 Releases Providing Messages For Stakeholders

    NASA Astrophysics Data System (ADS)

    Dixon, T.; Romanak, K.; Camps, A. P.

    2011-12-01

    Stakeholder viewpoints and beliefs about geologic carbon storage are not always accurate, yet they may affect the future of carbon capture and storage (CCS). Gaps in stakeholder understanding and perspectives must be addressed, and natural systems that release CO2 can be valuable tools for communicating difficult scientific concepts because they provide tangible examples of geologic principles at work. Stakeholder perceptions commonly involve a misunderstanding of geologic scale and mechanisms, and can be charged with emotions fueled by media coverage of natural disasters. One example of an event widely cited by stakeholders is the CO2 release at Lake Nyos in Cameroon in August 1986 that killed 1700 people. This event is commonly thought by stakeholders to be an analogue for a release from a CO2 storage site; however, this release occurred under a rare combination of circumstances (a 208-m-deep volcanic crater lake) not analogous to an engineered CO2 storage site. Stakeholders therefore gravitate towards natural systems to form concepts and opinions of how CO2 might behave in a geological environment, but they often choose systems that are not true analogues but that gain attention through the media because they are associated with a disaster. When chosen correctly, natural releases of CO2 may create a level of clarity for stakeholders by providing tangible concrete examples that explain difficult scientific principles and provide familiar reference points to adapt different viewpoints. We present suggestions and examples presented by scientists at an IEAGHG Workshop Natural Releases of CO2: Building Knowledge for CO2 Storage Environmental Impact Assessments', held at Maria Laach, Germany, November 2010 which brought together researchers from the EU, North America, Japan, and Australia. It also included field observations of natural CO2 releases around the Laacher See caldera lake, CO2 springs, and the Wallenborn CO2 geyser. New information from international

  14. Alteration of bentonite when contacted with supercritical CO2

    NASA Astrophysics Data System (ADS)

    Jinseok, K.; Jo, H. Y.; Yun, S. T.

    2014-12-01

    Deep saline formations overlaid by impermeable caprocks with a high sealing capacity are attractive CO2 storage reservoirs. Shales, which consist of mainly clay minerals, are potential caprocks for the CO2 storage reservoirs. The properties of clay minerals in shales may affect the sealing capacity of shales. In this study, changes in clay minerals' properties when contacted with supercritical (SC) CO2 at various conditions were investigated. Bentonite, whichis composed of primarily montmorillonite, was used as the clay material in this study. Batch reactor tests on wet bentonite samples in the presence of SC CO2 with or without aqueous phases were conducted at high pressure (12 MPa) and moderate temperature (50 oC) conditions for a week. Results show that the bentonite samples obtained from the tests with SC CO2 had less change in porosity than those obtained from the tests without SC CO2 (vacuum-drying) at a given reaction time, indicating that the bentonite samples dried in the presence of SC CO2 maintained their structure. These results suggest that CO2 molecules can diffuse into interlayer of montmorillonite, which is a primary mineral of bentonite, and form a single CO2 molecule layer or double CO2 molecule layers. The CO2 molecules can displace water molecules in the interlayer, resulting in maintaining the interlayer spacing when dehydration occurs. Noticeable changes in reacted bentonite samples obtained from the tests with an aqueous phase (NaCl, CaCl2, or sea water) are decreases in the fraction of plagioclase and pyrite and formation of carbonate minerals (i.e., calcite and dolomite) and halite. In addition, no significant exchanges of Na or Ca on the exchangeable complex of the montmorillonite in the presence of SC CO2 occurred, resulting in no significant changes in the swelling capacity of bentonite samples after reacting with SC CO2 in the presence of aqueous phases. These results might be attributed by the CO2 molecule layer, which prevents

  15. Acute and Chronic Exposure to CO2 in Space Flight

    NASA Technical Reports Server (NTRS)

    Alexander, D.; Wu, J.; Barr, Y. R.; Watkins, S. D.

    2010-01-01

    Spacecraft and space stations, similar to other habitable confined spaces such as submarines, need to provide a breathable atmosphere for their inhabitants. The inevitable production of CO2 during respiration necessitates life support systems that "scrub" the atmosphere and lower CO2 levels. Due to operational limitations associated with space flight (limited mass, volume, power, and consumables) CO2 is not scrubbed down to its terrestrial equivalent of 0.03% CO2 (ppCO2 of 0.23 mmHg), but is kept below 0.7% (ppCO2 of 5.3 mmHg), a level established in NASA s 180-day mission Spacecraft Maximum Allowable Concentration (SMAC) to be safe and unlikely to cause symptoms. Reports of space flight crewmembers becoming symptomatic with headaches, fatigue, and malaise at levels below those known to cause such symptoms terrestrially has prompted studies measuring the levels of CO2 on both the space shuttle and the space station. Data from cabin atmosphere sampling were collected on space shuttle missions STS-113, STS-122, STS-123, and International Space Station Expeditions 12-15 and 17, and the measured CO2 levels were then correlated to symptoms reported by the crew. The results indicate that a correlation exists between CO2 levels and symptomatology, however causality cannot be established at this time. While the short-term effects of elevated CO2 exposure are well known terrestrially, less is known regarding potential long-term effects of prolonged exposure to a CO2-rich environment or how the physiological changes caused by microgravity may interact with such exposures. Other challenges include limitations in the CO2 monitors used, lack of convection in the microgravity environment, and formation of localized CO2 pockets. As it is unclear if the unique environment of space increases sensitivity to CO2 or if other confounding factors are present, further research is planned to elucidate these points. At the same time, efforts are underway to update the SMAC to a lower level

  16. Can subterranean cave systems affect soil CO2 fluxes?

    NASA Astrophysics Data System (ADS)

    Krajnc, Bor; Ferlan, Mitja; Ogrinc, Nives

    2015-04-01

    Main factors affecting soil CO2 fluxes in most ecosystems are soil temperature and soil moisture. Nevertheless occasionally high soil CO2 fluxes were observed at carst areas, which could result from ventilation of subterranean cavities (Ferlan et al., 2011). The aim of this work was to determine the influence of cave ventilation to soil CO2 fluxes. Research was done in a dead-end passage of Postojna cave (Pisani rov) and on the surface area above the passage (Velika Jeršanova dolina) in south-western Slovenia. Inside the cave we measured CO2 concentrations, its carbon (13C) stable isotope composition, 222Rn activity concentrations, temperatures and air pressure. At the surface we had chosen two sampling plots; test plot above the cave and control. At both plots we measured soil CO2 fluxes with automatic chambers, CO2 concentrations, temperatures and carbon stable isotope composition of soil air at three different depths (0.2 m, 0.5 m and 0.8 m) and different meteorological parameters such as: air temperature, air pressure, wind speed an precipitation. To detect the cave influence, we compared two surface CO2 flux measurements with air temperatures and changes of CO2 concentrations in the cave atmosphere. Our results on CO2 concentrations in the gallery of the cave indicated that the ventilation of this particular gallery also depends on outside air temperatures. Outside temperature increased and corresponded to higher CO2 concentrations, whereas at lower temperatures (T < 9 oC) cave started to ventilate and exhaled CO2 reach air through unknown fissures and cracks. At the control plot the soil CO2 fluxes were in a good correlation with soil temperatures (r = 0.789, p =0.01), where greater soil temperatures correspond to greater soil CO2 fluxes. Soil CO2 fluxes at the plot above the cave did not show statistically significant correlations with soil temperatures or soil moisture indicating that other factors possibly cave ventilation could influence it. References

  17. A peak and decline in North Atlantic CO2 uptake

    NASA Astrophysics Data System (ADS)

    Halloran, Paul; Lebehot, Alice; Watson, Andy; McNeall, Doug; Schuster, Ute; Voelker, Christoph; Booth, Ben; Totterdell, Ian; Jones, Chris; Lambert, Hugo

    2016-04-01

    The oceans play a vital role in mitigating climate change by removing anthropogenic CO2 from the atmosphere. Presently, only around half of human-emitted CO2 remains in the atmosphere, with the rest being taken up by the land and ocean carbon sinks in approximately equal proportions. Of the ocean's CO2 uptake, that occurring in that high-latitude North Atlantic is the most intense. We develop a theoretical framework which proposes that Subpolar North Atlantic CO2 uptake is likely to peak and decline within the coming century. Considering the CMIP5 models within this framework, and comparing their behaviour to observations, we find that the CMIP5 models underestimate how close the real world's Subpolar North Atlantic CO2 uptake is to reaching peak uptake.

  18. CO2 reduction using adsorption followed by nonthermal plasma treatment

    NASA Astrophysics Data System (ADS)

    Nakajima, Kenji; Takahashi, Kazuya; Tanaka, Masanari; Kuroki, Tomoyuki; Okubo, Masaaki

    2015-10-01

    Carbon dioxide (CO2) is one of the main substances linked to global warming, and its emission should be reduced. In this study, a CO2 reduction treatment using an adsorbent and a nonthermal plasma flow is investigated. This treatment comprises a physical adsorption process and nitrogen (N2) plasma reduction process. In the physical adsorption process, CO2 is adsorbed by the adsorbent. In the N2 plasma reduction process, the adsorbed CO2 is reduced to CO by a nonthermal plasma flow that is generated by a plasma reactor with a circulating N2 plasma flow. The generated CO can be reused as a fuel. We estimate this experimental results by calculating conversion efficiency of CO2 to CO. In the N2 plasma reduction process, the CO concentration reaches approximately 1%, regardless of the number of experiments, and conversion efficiency reaches at most 5.3%.

  19. Towards Carbon-Neutral CO2 Conversion to Hydrocarbons.

    PubMed

    Mattia, Davide; Jones, Matthew D; O'Byrne, Justin P; Griffiths, Owen G; Owen, Rhodri E; Sackville, Emma; McManus, Marcelle; Plucinski, Pawel

    2015-12-01

    With fossil fuels still predicted to contribute close to 80 % of the primary energy consumption by 2040, methods to limit further CO2 emissions in the atmosphere are urgently needed to avoid the catastrophic scenarios associated with global warming. In parallel with improvements in energy efficiency and CO2 storage, the conversion of CO2 has emerged as a complementary route with significant potential. In this work we present the direct thermo-catalytic conversion of CO2 to hydrocarbons using a novel iron nanoparticle-carbon nanotube (Fe@CNT) catalyst. We adopted a holistic and systematic approach to CO2 conversion by integrating process optimization-identifying reaction conditions to maximize conversion and selectivity towards long chain hydrocarbons and/or short olefins-with catalyst optimization through the addition of promoters. The result is the production of valuable hydrocarbons in a manner that can approach carbon neutrality under realistic industrial process conditions. PMID:26564267

  20. Air exchange rates from atmospheric CO2 daily cycle

    PubMed Central

    Carrilho, João Dias; Mateus, Mário; Batterman, Stuart; da Silva, Manuel Gameiro

    2015-01-01

    We propose a new approach for measuring ventilation air exchange rates (AERs). The method belongs to the class of tracer gas techniques, but is formulated in the light of systems theory and signal processing. Unlike conventional CO2 based methods that assume the outdoor ambient CO2 concentration is constant, the proposed method recognizes that photosynthesis and respiration cycle of plants and processes associated with fuel combustion produce daily, quasi-periodic, variations in the ambient CO2 concentrations. These daily variations, which are within the detection range of existing monitoring equipment, are utilized for estimating ventilation rates without the need of a source of CO2 in the building. Using a naturally-ventilated residential apartment, AERs obtained using the new method compared favorably (within 10%) to those obtained using the conventional CO2 decay fitting technique. The new method has the advantages that no tracer gas injection is needed, and high time resolution results are obtained. PMID:26236090

  1. Effects of explicit atmospheric convection at high CO2

    PubMed Central

    Arnold, Nathan P.; Branson, Mark; Burt, Melissa A.; Abbot, Dorian S.; Kuang, Zhiming; Randall, David A.; Tziperman, Eli

    2014-01-01

    The effect of clouds on climate remains the largest uncertainty in climate change predictions, due to the inability of global climate models (GCMs) to resolve essential small-scale cloud and convection processes. We compare preindustrial and quadrupled CO2 simulations between a conventional GCM in which convection is parameterized and a “superparameterized” model in which convection is explicitly simulated with a cloud-permitting model in each grid cell. We find that the global responses of the two models to increased CO2 are broadly similar: both simulate ice-free Arctic summers, wintertime Arctic convection, and enhanced Madden–Julian oscillation (MJO) activity. Superparameterization produces significant differences at both CO2 levels, including greater Arctic cloud cover, further reduced sea ice area at high CO2, and a stronger increase with CO2 of the MJO. PMID:25024204

  2. Decadal predictions of the North Atlantic CO2 uptake

    PubMed Central

    Li, Hongmei; Ilyina, Tatiana; Müller, Wolfgang A.; Sienz, Frank

    2016-01-01

    As a major CO2 sink, the North Atlantic, especially its subpolar gyre region, is essential for the global carbon cycle. Decadal fluctuations of CO2 uptake in the North Atlantic subpolar gyre region are associated with the evolution of the North Atlantic Oscillation, the Atlantic meridional overturning circulation, ocean mixing and sea surface temperature anomalies. While variations in the physical state of the ocean can be predicted several years in advance by initialization of Earth system models, predictability of CO2 uptake has remained unexplored. Here we investigate the predictability of CO2 uptake variations by initialization of the MPI-ESM decadal prediction system. We find large multi-year variability in oceanic CO2 uptake and demonstrate that its potential predictive skill in the western subpolar gyre region is up to 4–7 years. The predictive skill is mainly maintained in winter and is attributed to the improved physical state of the ocean. PMID:27026490

  3. Is guava phenolic metabolism influenced by elevated atmospheric CO2?

    PubMed

    Mendes de Rezende, Fernanda; Pereira de Souza, Amanda; Silveira Buckeridge, Marcos; Maria Furlan, Cláudia

    2015-01-01

    Seedlings of Psidium guajava cv. Pedro Sato were distributed into four open-top chambers: two with ambient CO(2) (∼390 ppm) and two with elevated CO(2) (∼780 ppm). Monthly, five individuals of each chamber were collected, separated into root, stem and leaves and immediately frozen in liquid nitrogen. Chemical parameters were analyzed to investigate how guava invests the surplus carbon. For all classes of phenolic compounds analyzed only tannins showed significant increase in plants at elevated CO(2) after 90 days. There was no significant difference in dry biomass, but the leaves showed high accumulation of starch under elevated CO(2). Results suggest that elevated CO(2) seems to be favorable to seedlings of P. guajava, due to accumulation of starch and tannins, the latter being an important anti-herbivore substance. PMID:25129845

  4. Microfluidic studies of CO2 sequestration by frustrated Lewis pairs.

    PubMed

    Voicu, Dan; Abolhasani, Milad; Choueiri, Rachelle; Lestari, Gabriella; Seiler, Caroline; Menard, Gabriel; Greener, Jesse; Guenther, Axel; Stephan, Douglas W; Kumacheva, Eugenia

    2014-03-12

    Frustrated Lewis pairs (FLPs) comprising sterically hindered Lewis acids and bases offer the capability to reversibly capture CO2 under mild reaction conditions. The determination of equilibrium constants and thermodynamic properties of these reactions should enable assessment of the efficiency of a particular FLP system for CO2 sequestration and provide insights for design of new, efficient formulations of FLP catalysts for CO2 capture. We have developed a microfluidic approach to studies of FLP-CO2 reactions, which provides their thermodynamic characterization that is not accessible otherwise. The approach enables the determination of the equilibrium reaction constants at different temperatures, the enthalpy, the entropy, and the Gibbs energy of these reactions, as well as the enhancement factor. The microfluidic methodology has been validated by applying it to the well-characterized reaction of CO2 with a secondary amine. The microfluidic approach can be applied for fundamental thermodynamic studies of other gas-liquid reactions. PMID:24555752

  5. Compatibility of Medical-Grade Polymers with Dense CO2

    PubMed Central

    Jiménez, A; Thompson, G L; Matthews, M A; Davis, T A; Crocker, K; Lyons, J S; Trapotsis, A

    2009-01-01

    This study reports the effect of exposure to liquid carbon dioxide on the mechanical properties of selected medical polymers. The tensile strengths and moduli of fourteen polymers are reported. Materials were exposed to liquid CO2, or CO2 + trace amounts of aqueous H2O2, at 6.5 MPa and ambient temperature. Carbon dioxide uptake, swelling, and distortion were observed for the more amorphous polymers while polymers with higher crystallinity showed little effect from CO2 exposure. Changes in tensile strength were not statistically significant for most plastics, and most indicated good tolerance to liquid CO2. These results are relevant to evaluating the potential of liquid CO2-based sterilization technology. PMID:19756235

  6. CO2 -Breathing Induced Reversible Activation of Mechanophore within Microgels.

    PubMed

    Li, Meng; Lei, Lei; Zhang, Qi; Zhu, Shiping

    2016-06-01

    In this work, CO2 -breathing induced reversible activation of mechanophore within microgels is reported. The microgels are prepared through soap-free emulsion polymerization of CO2 -switchable monomer 2-(diethylamino)ethyl-methacrylate, using spiropyran (SP) based mechanophore MA-SP-MA as cross-linker. The microgels can be swollen by CO2 aeration. The swelling of microgels activates the SP mechanophore into merocyanine, causing distinguished color and fluorescence change. Moreover, these transitions are highly reversible, and the initial states of microgels can be easily recovered by "washing off" CO2 with N2 . The present contribution represents the first example of CO2 -breathing activation of mechanophore within microgels. PMID:27125764

  7. Decadal predictions of the North Atlantic CO2 uptake.

    PubMed

    Li, Hongmei; Ilyina, Tatiana; Müller, Wolfgang A; Sienz, Frank

    2016-01-01

    As a major CO2 sink, the North Atlantic, especially its subpolar gyre region, is essential for the global carbon cycle. Decadal fluctuations of CO2 uptake in the North Atlantic subpolar gyre region are associated with the evolution of the North Atlantic Oscillation, the Atlantic meridional overturning circulation, ocean mixing and sea surface temperature anomalies. While variations in the physical state of the ocean can be predicted several years in advance by initialization of Earth system models, predictability of CO2 uptake has remained unexplored. Here we investigate the predictability of CO2 uptake variations by initialization of the MPI-ESM decadal prediction system. We find large multi-year variability in oceanic CO2 uptake and demonstrate that its potential predictive skill in the western subpolar gyre region is up to 4-7 years. The predictive skill is mainly maintained in winter and is attributed to the improved physical state of the ocean. PMID:27026490

  8. Decadal predictions of the North Atlantic CO2 uptake

    NASA Astrophysics Data System (ADS)

    Li, Hongmei; Ilyina, Tatiana; Müller, Wolfgang A.; Sienz, Frank

    2016-03-01

    As a major CO2 sink, the North Atlantic, especially its subpolar gyre region, is essential for the global carbon cycle. Decadal fluctuations of CO2 uptake in the North Atlantic subpolar gyre region are associated with the evolution of the North Atlantic Oscillation, the Atlantic meridional overturning circulation, ocean mixing and sea surface temperature anomalies. While variations in the physical state of the ocean can be predicted several years in advance by initialization of Earth system models, predictability of CO2 uptake has remained unexplored. Here we investigate the predictability of CO2 uptake variations by initialization of the MPI-ESM decadal prediction system. We find large multi-year variability in oceanic CO2 uptake and demonstrate that its potential predictive skill in the western subpolar gyre region is up to 4-7 years. The predictive skill is mainly maintained in winter and is attributed to the improved physical state of the ocean.

  9. Exsolution Enhanced Oil Recovery with Concurrent CO2 Sequestration

    SciTech Connect

    Zuo, Lin; Benson, Sally M.

    2013-01-01

    A novel EOR method using carbonated water injection followed by depressurization is introduced. Results from micromodel experiments are presented to demonstrate the fundamental principles of this oil recovery method. A depressurization process (1 MPa/hr) was applied to a micromodel following carbonated water injection (Ca ≈ 10-5). The exsolved CO2 in water-filled pores blocked water flow in swiped portions and displaced water into oil-filled pores. Trapped oil after the carbonated water injection was mobilized by sequentially invading water. This method's self-distributed mobility control and local clogging was tested in a sandstone sample under reservoir conditions. A 10% incremental oil recovery was achieved by lowering the pressure 2 MPa below the CO2 liberation pressure. Additionally, exsolved CO2 resides in the pores of a reservoir as an immobile phase with a high residual saturation after oil production, exhibiting a potential synergy opportunity between CO2 EOR and CO2 sequestration

  10. [Model study on CO2 removal by photobioreactor].

    PubMed

    Cheng, Gui-Lin; Cheng, Li-Hua; Zhou, Cheng-Xu; Zhang, Lin; Chen, Huan-Lin

    2006-09-01

    The key point of study on CO2 removal by microalgae cultured in a photobioreactor is to improve CO2 removal capability. In this paper, a model of air-lift photobioreactor was developed by combination of conditions including the velocity of flow, the degree of mixing, the gas-liquid mass transfer and the rate of photosynthesis, and two corresponding simplified methods, such as time discretization and lumped parameters were put forward. Using a method of lumped parameters, the model for simulation of time course of DO, pH in the column air-lift photobioreactor and prediction of CO2, O2 concentrations in the outlet gas under different CO2 concentration in the aeration gas was thoroughly discussed. Experimental data were also used to verify the model which could potentially be applied to rational design of the photobioreactor, high-density culture of microalgae and efficient removal of CO2. PMID:17037209

  11. Homopolymers and Micelles in Supercritical CO2 : a SANS Study

    NASA Astrophysics Data System (ADS)

    Chillura-Martino, D.; McClain, J. B.; Canelas, D.; Betts, D.; Samulski, E. T.; Desimone, J. M.; Wignall, G. D.; Londono, J. D.; Triolo, R.

    1996-03-01

    Supercritical Carbon Dioxide (SC-CO_2) is becoming an attractive alternative to the liquid solvents traditionally used as polymerization media. We have applied small-angle neutron scattering (SANS) to characterize homopolymers and micellar systems in SC-CO_2. Although polymerizations are carried out at high pressures, the penetrating power of the neutron beam means that typical cell windows are virtually transparent. Homopolymers studied include polyfluoro-octyl acrylate (PFOA), hexafluoro-polypropylene oxide and Polydimethyl-siloxane. Also, copolymers of amphiphilic character in CO_2, were characterized via SANS. Systems studied were PFOA-polystyrene diblocks and PFOA-polyethyleneoxide (PFOA-PEO) graft copolymers, which swell as the CO2 medium is saturated with water. This work illustrates the utility of SANS to measure molecular dimensions, thermodynamic variables, molecular weights, micelle structures etc. in supercritical CO_2.

  12. Inverse modeling of CO2 sources and sinks using satellite observations of CO2 from TES and surface flask measurements

    SciTech Connect

    Nassar, Ray; Jones, DBA; Kulawik, SS; Worden, JR; Bowman, K; Andres, Robert Joseph; Suntharalingam, P; Chen, j.; Brenninkmeijer, CAM; Schuck, TJ; Conway, T.J.; Worthy, DE

    2011-01-01

    We infer CO2 surface fluxes using satellite observations of mid-tropospheric CO2 from the Tropospheric Emission Spectrometer (TES) and measurements of CO2 from surface flasks in a time-independent inversion analysis based on the GEOS-Chem model. Using TES CO2 observations over oceans, spanning 40 S 40 N, we find that the horizontal and vertical coverage of the TES and flask data are complementary. This complementarity is demonstrated by combining the datasets in a joint inversion, which provides better constraints than from either dataset alone, when a posteriori CO2 distributions are evaluated against independent ship and aircraft CO2 data. In particular, the joint inversion offers improved constraints in the tropics where surface measurements are sparse, such as the tropical forests of South America. Aggregating the annual surface-to-atmosphere fluxes from the joint inversion for the year 2006 yields 1.13 0.21 PgC for the global ocean, 2.77 0.20 PgC for the global land biosphere and 3.90 0.29 PgC for the total global natural flux (defined as the sum of all biospheric, oceanic, and biomass burning contributions but excluding CO2 emissions from fossil fuel combustion). These global ocean and global land fluxes are shown to be near the median of the broad range of values from other inversion results for 2006. To achieve these results, a bias in TES CO2 in the Southern Hemisphere was assessed and corrected using aircraft flask data, and we demonstrate that our results have low sensitivity to variations in the bias correction approach. Overall, this analysis suggests that future carbon data assimilation systems can benefit by integrating in situ and satellite observations of CO2 and that the vertical information provided by satellite observations of mid-tropospheric CO2 combined with measurements of surface CO2, provides an important additional constraint for flux inversions.

  13. Decadal predictions of the North Atlantic CO2 uptake

    NASA Astrophysics Data System (ADS)

    Li, Hongmei; Ilyina, Tatiana; Müller, Wolfgang

    2015-04-01

    Oceanic uptake of anthropogenic CO2 is critical for predicting and projecting climate and ocean acidification. The North Atlantic Ocean plays a crucial role in modulating global carbon cycle as a major CO2 sink region, and the subpolar gyre (SPG) region contributes the most to the variation of the North Atlantic CO2 uptake. Previous studies revealed abrupt warming/cooling events in the SPG region, with sea surface temperature (SST) increasing/decreasing by 1°C in only a few years. The abrupt SPG warming/cooling events can be predicted several years in advance by initialization of the earth system models. The CO2 uptake in the North Atlantic is largely driven by ocean mixing variations and SST anomalies. In this study, we investigate the response of the North Atlantic CO2 uptake to observed SST variations and explore the decadal predictability of the North Atlantic CO2 uptake during the period of 1961-2013 with the Max Planck Institute Earth System Model (MPI-ESM). Our results suggest significant inter-annual and decadal variability of the North Atlantic CO2 uptake which is closely related to the evolution of North Atlantic Oscillation (NAO) and corresponding oceanic mixing strength, and this coherence is confined to the western SPG region. We show that the potential predictability of CO2 uptake in the western SPG region is up to 4 years, which is similar to the prediction skill of SPG SST. Direct comparison of initialized simulations with observations implies prediction skill of the North Atlantic CO2 uptake. The predictability of both CO2 uptake and SST in the North Atlantic is assured by initialization of the Atlantic meridional overturning circulation (AMOC).

  14. Consumption-based accounting of CO2 emissions

    PubMed Central

    Davis, Steven J.; Caldeira, Ken

    2010-01-01

    CO2 emissions from the burning of fossil fuels are the primary cause of global warming. Much attention has been focused on the CO2 directly emitted by each country, but relatively little attention has been paid to the amount of emissions associated with the consumption of goods and services in each country. Consumption-based accounting of CO2 emissions differs from traditional, production-based inventories because of imports and exports of goods and services that, either directly or indirectly, involve CO2 emissions. Here, using the latest available data, we present a global consumption-based CO2 emissions inventory and calculations of associated consumption-based energy and carbon intensities. We find that, in 2004, 23% of global CO2 emissions, or 6.2 gigatonnes CO2, were traded internationally, primarily as exports from China and other emerging markets to consumers in developed countries. In some wealthy countries, including Switzerland, Sweden, Austria, the United Kingdom, and France, >30% of consumption-based emissions were imported, with net imports to many Europeans of >4 tons CO2 per person in 2004. Net import of emissions to the United States in the same year was somewhat less: 10.8% of total consumption-based emissions and 2.4 tons CO2 per person. In contrast, 22.5% of the emissions produced in China in 2004 were exported, on net, to consumers elsewhere. Consumption-based accounting of CO2 emissions demonstrates the potential for international carbon leakage. Sharing responsibility for emissions among producers and consumers could facilitate international agreement on global climate policy that is now hindered by concerns over the regional and historical inequity of emissions. PMID:20212122

  15. Effect of Urbanization on River CO2 Emissons

    NASA Astrophysics Data System (ADS)

    Zeng, F.; Masiello, C. A.

    2007-12-01

    CO2 supersaturation in rivers has been reported for a number of different systems: tropical (e.g. Amazon1), subtropical (e.g. Xijiang River in China2) and temperate (e.g. Hudson3), indicating rivers' role as a source of atmospheric CO2 in regional net carbon budgets. In situ respiration of organic carbon is responsible for the high CO2 concentrations in rivers1. Because this organic carbon primarily originates on land1, land use practices may alter sources and character of this organic carbon significantly, potentially impacting river CO2 emissions. Urbanization is an important, expanding global land use. We are researching the effect of urbanization on river CO2 emissions. In this study, partial pressure of dissolved CO2 (pCO2) and radiocarbon (14C) contents of riverine dissolved inorganic carbon (DIC) are directly measured in time series in Buffalo Bayou and Brays Bayou, two of the main rivers draining Houston, Texas, a developed humid subtropical city. The watersheds of both bayous are entirely unbanized. We will report seasonal trends of pCO2 and 14C of riverine DIC to estimate sources and turnover times of dissolved CO2. For comparison, we are also measuring pCO2 and DIC 14C in Spring Creek, Texas, a nearby river which has a mixed forest/agriculture watershed, as a non-urbanized counterpart to Buffalo and Brays Bayous. References: 1. E. Mayorga et al., Nature 436, 538 (2005). 2. G. Yao et al., Sci. Tot. Environ. 376, 255 (2007). 3. P.A. Raymond, N.F. Caraco, and J.J. Cole, Estuaries 20, 381 (1997).

  16. Does elevated CO2 alter silica uptake in trees?

    DOE PAGESBeta

    Fulweiler, Robinson W.; Maguire, Timothy J.; Carey, Joanna C.; Finzi, Adrien C.

    2015-01-13

    Human activities have greatly altered global carbon (C) and Nitrogen (N) cycling. In fact, atmospheric concentrations of carbon dioxide (CO2) have increased 40% over the last century and the amount of N cycling in the biosphere has more than doubled. In an effort to understand how plants will respond to continued global CO2 fertilization, longterm free-air CO2 enrichment experiments have been conducted at sites around the globe. Here we examine how atmospheric CO2 enrichment and N fertilization affects the uptake of silicon (Si) in the Duke Forest, North Carolina, a stand dominated by Pinus taeda (loblolly pine), and five hardwoodmore » species. Specifically, we measured foliar biogenic silica concentrations in five deciduous and one coniferous species across three treatments: CO2 enrichment, N enrichment, and N and CO2 enrichment. We found no consistent trends in foliar Si concentration under elevated CO2, N fertilization, or combined elevated CO2 and N fertilization. However, two-thirds of the tree species studied here have Si foliar concentrations greater than well-known Si accumulators, such as grasses. Based on net primary production values and aboveground Si concentrations in these trees, we calculated forest Si uptake rates under control and elevated CO2 concentrations. Due largely to increased primary production, elevated CO2 enhanced the magnitude of Si uptake between 20 and 26%, likely intensifying the terrestrial silica pump. This uptake of Si by forests has important implications for Si export from terrestrial systems, with the potential to impact C sequestration and higher trophic levels in downstream ecosystems.« less

  17. Does elevated CO2 alter silica uptake in trees?

    PubMed

    Fulweiler, Robinson W; Maguire, Timothy J; Carey, Joanna C; Finzi, Adrien C

    2014-01-01

    Human activities have greatly altered global carbon (C) and Nitrogen (N) cycling. In fact, atmospheric concentrations of carbon dioxide (CO2) have increased 40% over the last century and the amount of N cycling in the biosphere has more than doubled. In an effort to understand how plants will respond to continued global CO2 fertilization, long-term free-air CO2 enrichment experiments have been conducted at sites around the globe. Here we examine how atmospheric CO2 enrichment and N fertilization affects the uptake of silicon (Si) in the Duke Forest, North Carolina, a stand dominated by Pinus taeda (loblolly pine), and five hardwood species. Specifically, we measured foliar biogenic silica concentrations in five deciduous and one coniferous species across three treatments: CO2 enrichment, N enrichment, and N and CO2 enrichment. We found no consistent trends in foliar Si concentration under elevated CO2, N fertilization, or combined elevated CO2 and N fertilization. However, two-thirds of the tree species studied here have Si foliar concentrations greater than well-known Si accumulators, such as grasses. Based on net primary production values and aboveground Si concentrations in these trees, we calculated forest Si uptake rates under control and elevated CO2 concentrations. Due largely to increased primary production, elevated CO2 enhanced the magnitude of Si uptake between 20 and 26%, likely intensifying the terrestrial silica pump. This uptake of Si by forests has important implications for Si export from terrestrial systems, with the potential to impact C sequestration and higher trophic levels in downstream ecosystems. PMID:25628636

  18. Diffusion of CO2 During Hydrate Formation and Dissolution

    SciTech Connect

    Franklin M. Orr, Jr.

    2002-08-20

    Experiments were performed to measure the rate of diffusion of CO2 through hydrate films. Hydrate films were created in a capillary tube, and the growth of the hydrate film was measured. Difficulties were encountered in creating hydrate repeatedly, and some non-uniform growth of the films was observed. Sufficient observations were obtained to demonstrate that hydrate growth occurs preferentially on the hydrate/water side of the interface, rather than at the hydrate/CO2 interface. Diffusion coefficients were estimated from observations of the rate of growth of the hydrate film along with estimates of the solubility of CO2 in water and of the concentration gradient across the hydrate layer. The experimental observations indicate that hydrate formation occurs much more rapidly at the hydrate water interface than at the hydrate/CO2 interface. Any growth of hydrate at the CO2/hydrate interface was too slow to be observed at the time scale of the experiments. That observation is consistent with the idea that CO2 can move more easily through the hydrate, presumably by hopping between hydrate cages, than water can move through the hydrate, presumably by lattice hopping. Estimated diffusion coefficients were in the range 1-3E-06 cm2/sec. Those values are about an order of magnitude lower than the diffusion coefficient for CO2 in liquid water, but four orders of magnitude larger than the value for diffusion of CO2 in a solid. The rate of diffusion through the hydrate controls both the creation of new hydrate at the hydrate/water interface and the rate at which CO2 dissolves in the liquid water and diffuses away from the hydrate layer. Formation of a hydrate layer reduces the rate at which CO2 dissolves in liquid water.

  19. CO2 on the International Space Station: An Operations Update

    NASA Technical Reports Server (NTRS)

    Law, Jennifer; Alexander, David

    2016-01-01

    PROBLEM STATEMENT: We describe CO2 symptoms that have been reported recently by crewmembers on the International Space Station and our continuing efforts to control CO2 to lower levels than historically accepted. BACKGROUND: Throughout the International Space Station (ISS) program, anecdotal reports have suggested that crewmembers develop CO2-related symptoms at lower CO2 levels than would be expected terrestrially. Since 2010, operational limits have controlled the 24-hour average CO2 to 4.0 mm Hg, or below as driven by crew symptomatology. In recent years, largely due to increasing awareness by crew and ground team, there have been increased reports of crew symptoms. The aim of this presentation is to discuss recent observations and operational impacts to lower CO2 levels on the ISS. CASE PRESENTATION: Crewmembers are routinely asked about CO2 symptoms in their weekly private medical conferences with their crew surgeons. In recent ISS expeditions, crewmembers have noted symptoms attributable to CO2 starting at 2.3 mmHg. Between 2.3 - 2.7 mm Hg, fatigue and full-headedness have been reported. Between 2.7 - 3.0 mm Hg, there have been self-reports of procedure missed steps or procedures going long. Above 3.0 - 3.4 mm Hg, headaches have been reported. A wide range of inter- and intra-individual variability in sensitivity to CO2 have been noted. OPERATIONAL / CLINICAL RELEVANCE: These preliminary data provide semi-quantitative ranges that have been used to inform a new operational limit of 3.0 mmHg as a compromise between systems capabilities and the recognition that there are human health and performance impacts at recent ISS CO2 levels. Current evidence would suggest that an operational limit between 0.5 and 2.0 mm Hg may maintain health and performance. Future work is needed to establish long-term ISS and future vehicle operational limits.

  20. Does elevated CO2 alter silica uptake in trees?

    PubMed Central

    Fulweiler, Robinson W.; Maguire, Timothy J.; Carey, Joanna C.; Finzi, Adrien C.

    2015-01-01

    Human activities have greatly altered global carbon (C) and Nitrogen (N) cycling. In fact, atmospheric concentrations of carbon dioxide (CO2) have increased 40% over the last century and the amount of N cycling in the biosphere has more than doubled. In an effort to understand how plants will respond to continued global CO2 fertilization, long-term free-air CO2 enrichment experiments have been conducted at sites around the globe. Here we examine how atmospheric CO2 enrichment and N fertilization affects the uptake of silicon (Si) in the Duke Forest, North Carolina, a stand dominated by Pinus taeda (loblolly pine), and five hardwood species. Specifically, we measured foliar biogenic silica concentrations in five deciduous and one coniferous species across three treatments: CO2 enrichment, N enrichment, and N and CO2 enrichment. We found no consistent trends in foliar Si concentration under elevated CO2, N fertilization, or combined elevated CO2 and N fertilization. However, two-thirds of the tree species studied here have Si foliar concentrations greater than well-known Si accumulators, such as grasses. Based on net primary production values and aboveground Si concentrations in these trees, we calculated forest Si uptake rates under control and elevated CO2 concentrations. Due largely to increased primary production, elevated CO2 enhanced the magnitude of Si uptake between 20 and 26%, likely intensifying the terrestrial silica pump. This uptake of Si by forests has important implications for Si export from terrestrial systems, with the potential to impact C sequestration and higher trophic levels in downstream ecosystems. PMID:25628636

  1. On the Formation of CO2 and Other Interstellar Ices

    NASA Astrophysics Data System (ADS)

    Garrod, R. T.; Pauly, T.

    2011-07-01

    We investigate the formation and evolution of interstellar dust-grain ices under dark-cloud conditions, with a particular emphasis on CO2. We use a three-phase model (gas/surface/mantle) to simulate the coupled gas-grain chemistry, allowing the distinction of the chemically active surface from the ice layers preserved in the mantle beneath. The model includes a treatment of the competition between barrier-mediated surface reactions and thermal-hopping processes. The results show excellent agreement with the observed behavior of CO2, CO, and water ice in the interstellar medium. The reaction of the OH radical with CO is found to be efficient enough to account for CO2 ice production in dark clouds. At low visual extinctions, with dust temperatures gsim12 K, CO2 is formed by direct diffusion and reaction of CO with OH; we associate the resultant CO2-rich ice with the observational polar CO2 signature. CH4 ice is well correlated with this component. At higher extinctions, with lower dust temperatures, CO is relatively immobile and thus abundant; however, the reaction of H and O atop a CO molecule allows OH and CO to meet rapidly enough to produce a CO:CO2 ratio in the range ~2-4, which we associate with apolar signatures. We suggest that the observational apolar CO2/CO ice signatures in dark clouds result from a strongly segregated CO:H2O ice, in which CO2 resides almost exclusively within the CO component. Observed visual-extinction thresholds for CO2, CO, and H2O are well reproduced by depth-dependent models. Methanol formation is found to be strongly sensitive to dynamical timescales and dust temperatures.

  2. Detecting anomalous CO 2 flux using space borne spectroscopy

    NASA Astrophysics Data System (ADS)

    Gangopadhyay, Prasun K.; van der Meer, Freek; van Dijk, Paul

    2009-02-01

    Over the time-scale, earth's atmospheric CO 2 concentration has varied and that is mostly determined by balance among the geochemical processes including burial of organic carbon in sediments, silicate rock weathering and volcanic activity. The best recorded atmospheric CO 2 variability is derived from Vostok ice core that records last four glacial/interglacial cycles. The present CO 2 concentration of earth's atmosphere has exceeded far that it was predicted from the ice core data. Other than rapid industrialization and urbanization since last century, geo-natural hazards such as volcanic activity, leakage from hydrocarbon reservoirs and spontaneous combustion of coal contribute a considerable amount of CO 2 to the atmosphere. Spontaneous combustion of coal is common occurrence in most coal producing countries and sometimes it could be in an enormous scale. Remote sensing has already proved to be a significant tool in coalfire identification and monitoring studies. However, coalfire related CO 2 quantification from remote sensing data has not endeavoured yet by scientific communities because of low spectral resolution of commercially available remote sensing data and relatively sparse CO 2 plume than other geological hazards like volcanic activity. The present research has attempted two methods to identify the CO 2 flux emitted from coalfires in a coalmining region in north China. Firstly, a band rationing method was used for column atmospheric retrieval of CO 2 and secondly atmospheric models were simulated in fast atmospheric signature code (FASCOD) to understand the local radiation transport and then the model was implemented with the inputs from hyperspectral remote sensing data. It was observed that retrieval of columnar abundance of CO 2 with the band rationing method is faster as less simulation required in FASCOD. Alternatively, the inversion model could retrieve CO 2 concentration from a (certain) source because it excludes the uncertainties in the higher

  3. A Microphysical Model of CO_2 Snow on Mars

    NASA Astrophysics Data System (ADS)

    Wood, S. E.; Richardson, M. I.; Paige, D. A.

    1996-09-01

    Atmospheric condensation of CO_2 is a critical but poorly understood part of the Martian seasonal CO_2 cycle. During polar night, the latent heat released by CO_2 condensation is the major heat source, and CO2 clouds can substantially reduce the infrared emission from the condensing seasonal CO_2 polar cap. The CO_2 snow which precipitates from the atmosphere may also help determine the radiative and physical characteristics of the seasonal CO_2 polar caps, depending on the relative amount of condensation which takes place in the atmosphere. Previous models of atmospheric CO_2 condensation on Mars have not taken into account the finite rates of nucleation, growth, and sedimentation, or the radiative effects of the CO_2 clouds themselves, and their results may be inconsistent with available data. In order to address these issues, we have developed a one-dimensional model of the growth and precipitation of CO_2 snow in the polar night atmosphere of Mars. The model includes a realistic treatment of the microphysical processes of heat and mass transfer in both the continuum and free molecular regimes, as well as the transition region. We have also taken into account surface kinetics, or the finite rate at which molecules can be incorporated into the crystal lattice. We will present model calculations of snow particle growth and sedimentation rates for different values of atmospheric supersaturation and nucleation height. These results are compared with Viking IRTM observations to place constraints on the amount of atmospheric condensation. We will also present predictions of what TES and MOLA will see on Mars Global Surveyor.

  4. Primary productivity and water balance of grassland vegetation on three soils in a continuous CO2 gradient: initial results from the lysimeter CO2 gradient experiment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field studies of atmospheric CO2 effects on ecosystem processes usually include only a few levels of CO2 and a single soil type, making it difficult to ascertain the shape of ecosystem responses to increasing CO2 or to generalize CO2 effects across ecosystems on varying soil types. The Lysimeter CO2...

  5. On the statistical optimality of CO2 atmospheric inversions assimilating CO2 column retrievals

    NASA Astrophysics Data System (ADS)

    Chevallier, F.

    2015-10-01

    The extending archive of the Greenhouse Gases Observing Satellite (GOSAT) measurements (now covering about 6 years) allows increasingly robust statistics to be computed, that document the performance of the corresponding retrievals of the column-average dry air-mole fraction of CO2 (XCO2). Here, we demonstrate that atmospheric inversions cannot be rigorously optimal when assimilating current XCO2 retrievals, even with averaging kernels, in particular because retrievals and inversions use different assumption about prior uncertainty. We look for some practical evidence of this sub-optimality from the view point of atmospheric inversion by comparing a model simulation constrained by surface air-sample measurements with one of the GOSAT retrieval products (NASA's ACOS). The retrieval-minus-model differences result from various error sources, both in the retrievals and in the simulation: we discuss the plausibility of the origin of the major patterns. We find systematic retrieval errors over the dark surfaces of high-latitude lands and over African savannahs. More importantly, we also find a systematic over-fit of the GOSAT radiances by the retrievals over land for the high-gain detector mode, which is the usual observation mode. The over-fit is partially compensated by the retrieval bias-correction. These issues are likely common to other retrieval products and may explain some of the surprising and inconsistent CO2 atmospheric inversion results obtained with the existing GOSAT retrieval products. We suggest that reducing the observation weight in the retrieval schemes (for instance so that retrieval increments to the retrieval prior values are halved for the studied retrieval product) would significantly improve the retrieval quality and reduce the need for (or at least reduce the complexity of) ad-hoc retrieval bias correction.

  6. Effects of Elevated Atmospheric CO2 on Soil CO2 Efflux in Conventional and Conservation Cropping Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elevated atmospheric carbon dioxide (CO2) can affect both the quantity and quality of plant tissues produced, which will impact the cycling and storage of carbon (C) within plant/soil systems and thus the rate of CO2 release back to the atmosphere. Research is needed to more accurately quantify the...

  7. Large CO2 effluxes at night and during synoptic weather events significantly contribute to CO2 emissions from a reservoir

    NASA Astrophysics Data System (ADS)

    Liu, Heping; Zhang, Qianyu; Katul, Gabriel G.; Cole, Jonathan J.; Chapin, F. Stuart, III; MacIntyre, Sally

    2016-06-01

    CO2 emissions from inland waters are commonly determined by indirect methods that are based on the product of a gas transfer coefficient and the concentration gradient at the air water interface (e.g., wind-based gas transfer models). The measurements of concentration gradient are typically collected during the day in fair weather throughout the course of a year. Direct measurements of eddy covariance CO2 fluxes from a large inland water body (Ross Barnett reservoir, Mississippi, USA) show that CO2 effluxes at night are approximately 70% greater than those during the day. At longer time scales, frequent synoptic weather events associated with extratropical cyclones induce CO2 flux pulses, resulting in further increase in annual CO2 effluxes by 16%. Therefore, CO2 emission rates from this reservoir, if these diel and synoptic processes are under-sampled, are likely to be underestimated by approximately 40%. Our results also indicate that the CO2 emission rates from global inland waters reported in the literature, when based on indirect methods, are likely underestimated. Field samplings and indirect modeling frameworks that estimate CO2 emissions should account for both daytime–nighttime efflux difference and enhanced emissions during synoptic weather events. The analysis here can guide carbon emission sampling to improve regional carbon estimates.

  8. CO2 Exsolution from CO2 Saturated Water: Core-Scale Experiments and Focus on Impacts of Pressure Variations.

    PubMed

    Xu, Ruina; Li, Rong; Ma, Jin; Jiang, Peixue

    2015-12-15

    For CO2 sequestration and utilization in the shallow reservoirs, reservoir pressure changes are due to the injection rate changing, a leakage event, and brine withdrawal for reservoir pressure balance. The amounts of exsolved CO2 which are influenced by the pressure reduction and the subsequent secondary imbibition process have a significant effect on the stability and capacity of CO2 sequestration and utilization. In this study, exsolution behavior of the CO2 has been studied experimentally using a core flooding system in combination with NMR/MRI equipment. Three series of pressure variation profiles, including depletion followed by imbibitions without or with repressurization and repetitive depletion and repressurization/imbibition cycles, were designed to investigate the exsolution responses for these complex pressure variation profiles. We found that the exsolved CO2 phase preferentially occupies the larger pores and exhibits a uniform spatial distribution. The mobility of CO2 is low during the imbibition process, and the residual trapping ratio is extraordinarily high. During the cyclic pressure variation process, the first cycle has the largest contribution to the amount of exsolved CO2. The low CO2 mobility implies a certain degree of self-sealing during a possible reservoir depletion. PMID:26509211

  9. Multiwell CO2 injectivity: impact of boundary conditions and brine extraction on geologic CO2 storage efficiency and pressure buildup.

    PubMed

    Heath, Jason E; McKenna, Sean A; Dewers, Thomas A; Roach, Jesse D; Kobos, Peter H

    2014-01-21

    CO2 storage efficiency is a metric that expresses the portion of the pore space of a subsurface geologic formation that is available to store CO2. Estimates of storage efficiency for large-scale geologic CO2 storage depend on a variety of factors including geologic properties and operational design. These factors govern estimates on CO2 storage resources, the longevity of storage sites, and potential pressure buildup in storage reservoirs. This study employs numerical modeling to quantify CO2 injection well numbers, well spacing, and storage efficiency as a function of geologic formation properties, open-versus-closed boundary conditions, and injection with or without brine extraction. The set of modeling runs is important as it allows the comparison of controlling factors on CO2 storage efficiency. Brine extraction in closed domains can result in storage efficiencies that are similar to those of injection in open-boundary domains. Geomechanical constraints on downhole pressure at both injection and extraction wells lower CO2 storage efficiency as compared to the idealized scenario in which the same volumes of CO2 and brine are injected and extracted, respectively. Geomechanical constraints should be taken into account to avoid potential damage to the storage site. PMID:23971876

  10. Large CO2 effluxes at night and during synoptic weather events significantly contribute to CO2 emissions from a reservoir

    DOE PAGESBeta

    Liu, Heping; Zhang, Qianyu; Katul, Gabriel G.; Cole, Jonathan J.; Chapin, III, F. Stuart; MacIntyre, Sally

    2016-05-24

    CO2 emissions from inland waters are commonly determined by indirect methods that are based on the product of a gas transfer coefficient and the concentration gradient at the air water interface (e.g., wind-based gas transfer models). The measurements of concentration gradient are typically collected during the day in fair weather throughout the course of a year. Direct measurements of eddy covariance CO2 fluxes from a large inland water body (Ross Barnett reservoir, Mississippi, USA) show that CO2 effluxes at night are approximately 70% greater than those during the day. At longer time scales, frequent synoptic weather events associated with extratropicalmore » cyclones induce CO2 flux pulses, resulting in further increase in annual CO2 effluxes by 16%. Therefore, CO2 emission rates from this reservoir, if these diel and synoptic processes are under-sampled, are likely to be underestimated by approximately 40%. Our results also indicate that the CO2 emission rates from global inland waters reported in the literature, when based on indirect methods, are likely underestimated. Field samplings and indirect modeling frameworks that estimate CO2 emissions should account for both daytime-nighttime efflux difference and enhanced emissions during synoptic weather events. Furthermore, the analysis here can guide carbon emission sampling to improve regional carbon estimates.« less

  11. Characterization of CO2 and mixed methane/CO2 hydrates intercalated in smectites by means of atomistic calculations.

    PubMed

    Martos-Villa, Rubén; Mata, M Pilar; Sainz-Díaz, C Ignacio

    2014-04-01

    The recent increase in anthropogenic CO2 gas released to the atmosphere and its contribution to global warming make necessary to investigate new ways of CO2 storage. Injecting CO2 into subsurface CH4 hydrate reservoirs would displace some of the CH4 in the hydrate crystal lattice, converting simple CH4 hydrates into either simple CO2 hydrates or mixed CH4CO2 hydrates. Molecular simulations were performed to determine the structure and behavior of CO2 and mixed hydrate complexes in the interlayer of Na-rich montmorillonite and beidellite smectite. Molecular Dynamics (MD) simulations used NPT ensembles in a 4×4×1 supercell comprised of montmorillonite or beidellite with CO2 or mixed CH4/CO2 hydrate complexes in the interlayer. The smectite 2:1 layer surface helps provide a stabilizing influence on the formation of gas hydrate complexes. The type of smectite affects the stability of the smectite-hydrate complexes, where high charge located on the tetrahedral layer of the smectites disfavor the formation of hydrate complexes. PMID:24569124

  12. Soil CO2 respiration: Comparison of chemical titration, CO2 IRGA analysis and the Solvita gel system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this research is to compare the results of measured soil CO2 respiration using three methods: (1) titration method; (2) Infrared gas analysis (IRGA); and (3) the Solvita gel system for soil CO2 analysis. We acquired 36 soil samples from across the USA for comparison which ranged in pH...

  13. An estimate of monthly global emissions of anthropogenic CO2: Impact on the seasonal cycle of atmospheric CO2

    SciTech Connect

    Erickson, D; Mills, R; Gregg, J; Blasing, T J; Hoffman, F; Andres, Robert Joseph; Devries, M; Zhu, Z; Kawa, S

    2008-01-01

    Monthly estimates of the global emissions of anthropogenic CO2 are presented. Approximating the seasonal CO2 emission cycle using a 2-harmonic Fourier series with coefficients as a function of latitude, the annual fluxes are decomposed into monthly flux estimates based on data for the United States and applied globally. These monthly anthropogenic CO2 flux estimates are then used to model atmospheric CO2 concentrations using meteorological fields from the NASA GEOS-4 data assimilation system. We find that the use of monthly resolved fluxes makes a significant difference in the seasonal cycle of atmospheric CO2 in and near those regions where anthropogenic CO2 is released to the atmosphere. Local variations of 2-6 ppmv CO2 in the seasonal cycle amplitude are simulated; larger variations would be expected if smaller source-receptor distances could be more precisely specified using a more refined spatial resolution. We also find that in the midlatitudes near the sources, synoptic scale atmospheric circulations are important in the winter and that boundary layer venting and diurnal rectifier effects are more important in the summer. These findings have implications for inverse-modeling efforts that attempt to estimate surface source/sink regions especially when the surface sinks are colocated with regions of strong anthropogenic CO2 emissions.

  14. Apatite as a Tool for Tracking Magmatic CO2 Contents

    NASA Astrophysics Data System (ADS)

    Riker, J.; Humphreys, M.; Brooker, R. A.

    2014-12-01

    CO2 plays a fundamental role in the evolution of magmatic and volcanic systems, but its low solubility in silicate melts means that direct records of magmatic CO2 concentrations remain elusive. The phosphate mineral apatite is unique among igneous minerals in its capacity to accommodate all major magmatic volatiles (H2O, F, Cl, CO2 and S). Although interest in apatite as a tool for tracking magmatic volatile contents (namely H2O, F, and Cl) has increased in recent years, its potential as a record of magmatic CO2contents remains untapped. We present the results of high-temperature, high-pressure experiments investigating the partitioning behaviour of CO2 between apatite and basaltic melt. Experiments were run in piston cylinder apparatus at 1 GPa and 1250 °C, with a slow initial cooling ramp employed to facilitate crystal growth. Each charge contained the starting basaltic powder doped with Ca-phosphate and variable proportions of H2O, CO2, and F. Run products are glass-rich charges containing 15-25 vol% large, euhedral apatite crystals (± cpx and minor biotite). Experimental apatites and glasses have been characterised by BSE imaging, electron microprobe, and ion microprobe. Apatites range in composition from near-endmember fluorapatite (3.0 wt% F), to near-endmember hydroxyapatite (1.7 wt% H2O), to carbon-rich apatite containing up to 1.6 wt% CO2. Apatite compositions are stoichiometric if all anions (F-, OH-, and CO32—) lie in the channel site, suggesting an "A-type" substitution under these conditions (i.e. CO32— + [] = 2X—, where X is another channel anion and [] is a vacancy; e.g. Fleet et al. 2004). Importantly, CO2 partitions readily into apatite at all fluid compositions considered here. CO2 is also more compatible in apatite than water at our run conditions, with calculated H2O-CO2 exchange coefficients close to or greater than 1. Our results indicate that when channel ions are primarily occupied by H2O and CO2 (i.e. F- and Cl-poor magmatic systems

  15. Spectral nature of CO2 adsorption onto meteorites

    USGS Publications Warehouse

    Berlanga, Genesis; Hibbitts, Charles A; Takir, Driss; Dyar, Draby M; Elizabeth Sklute

    2016-01-01

    Previous studies have identified carbon dioxide (CO2) on the surfaces of Jovian and Galilean satellites in regions of non-ice material that are too warm for CO2 ice to exist. CO2 ice would quickly sublimate if not retained by a less-volatile material. To ascertain what non-ice species may be responsible for stabilizing this CO2, we performed CO2 gas adsorption experiments on thirteen powdered CM, CI, and CV carbonaceous chondrite meteorites. Reflectance spectra of the ν3 feature associated with adsorbed CO2 near 4.27 μm were recorded. Results show that many meteorites adsorbed some amount of CO2, as evidenced by an absorption feature that was stable over several hours at ultra-high vacuum (UHV) and high vacuum, (1.0×10−8 and 1.0×10−7 Torr, respectively). Ivuna, the only CI chondrite studied, adsorbed significantly more CO2 than the others. We found that CO2 abundance did not vary with ‘water’ abundance, organics, or carbonates as inferred from the area of the 3-μm band, the 3.2-3.4 μm C-H feature, and the ∼3.8-μm band respectively, but did correlate with hydrous/anhydrous phyllosilicate ratios. Furthermore, we did not observe CO2 ice because the position of the CO2 feature was generally shifted 3-10 nm from that of the 4.27 μm absorption characteristic of ice. The strongest compositional relationship observed was a possible affinity of CO2 for total FeO abundance and complex clay minerals, which make up the bulk of the CI chondrite matrix. This finding implies that the most primitive refractory materials in the Solar System may also act as reservoirs of CO2, and possibly other volatiles, delivering them to parts of the Solar System where their ices would not be stable.

  16. CO2-induced changes in mineral stoichiometry of wheat grains

    NASA Astrophysics Data System (ADS)

    Broberg, Malin; Pleijel, Håkan; Högy, Petra

    2016-04-01

    A comprehensive review of experiments with elevated CO2 (eCO2) presenting data on grain mineral concentration in wheat grain was made. Data were collected both from FACE (Free-Air CO2 Enrichment) and OTC (Open-Top Chamber) experiments. Analysis was made i) by deriving response functions for the relative effect on yield and mineral concentration in relation to CO2 concentration, ii) meta-analysis to test the magnitude and significance of observed effects and iii) comparison of the CO2 effect on the accumulation of different minerals in relation to accumulation of biomass and accumulation of N. Data were obtained for the following minerals: N, Zn, Mn, K, Ca, Mg, P, Fe, S, Cr, Cu, Cd and Na. In addition, data for starch, the dominating carbohydrate of wheat grain, were extracted. The responses ranged from near zero effects to strong negative effects of eCO2 on mineral concentration. The order of effect size was the following (from largest to smallest effect) for the different elements: Fe, Ca, S, Zn, Cd, N, Mg, Mn, P, Cu, Cr, K and Na. Particularly strong negative impacts of eCO2 were found in the essential mineral elements Fe, S, Ca, Zn and Mg. Especially Fe, Zn and Mg are nutrients for which deficiency in humans is a problem in todaýs world. The rather large differences in response of different elements indicated that the CO2-induced responses cannot be explained by a simple growth dilution model. Rather, uptake and transport mechanisms may have to be considered in greater detail, as well as the link of different elements with the uptake of nitrogen, the quantitatively dominating mineral nutrient, to explain the observed pattern. No effect of eCO2 on starch concentration could be demonstrated. This substantiates the rejection of a simple dilution model, since one would expect starch concentrations to be elevated in order to explain reduced mineral concentrations by carbohydrate dilution. The concentrations of toxic Cd was negatively affected, in principle a

  17. Cerebral blood flow during orthostasis: role of arterial CO2.

    PubMed

    Serrador, J M; Hughson, R L; Kowalchuk, J M; Bondar, R L; Gelb, A W

    2006-04-01

    Reductions in end-tidal Pco(2) (Pet(CO(2))) during upright posture have been suggested to be the result of hyperventilation and the cause of decreases in cerebral blood flow (CBF). The goal of this study was to determine whether decreases in Pet(CO(2)) reflected decreases in arterial Pco(2) (Pa(CO(2))) and their relation to increases in alveolar ventilation (Va) and decreases in CBF. Fifteen healthy subjects (10 women and 5 men) were subjected to a 10-min head-up tilt (HUT) protocol. Pa(CO(2)), Va, and cerebral flow velocity (CFV) in the middle and anterior cerebral arteries were examined. In 12 subjects who completed the protocol, reductions in Pet(CO(2)) and Pa(CO(2)) (-1.7 +/- 0.5 and -1.1 +/- 0.4 mmHg, P < 0.05) during minute 1 of HUT were associated with a significant increase in Va (+0.7 +/- 0.3 l/min, P < 0.05). However, further decreases in Pa(CO(2)) (-0.5 +/- 0.5 mmHg, P < 0.05), from minute 1 to the last minute of HUT, occurred even though Va did not change significantly (-0.2 +/- 0.3 l/min, P = not significant). Similarly, CFV in the middle and anterior cerebral arteries decreased (-7 +/- 2 and -8 +/- 2%, P < 0.05) from minute 1 to the last minute of HUT, despite minimal changes in Pa(CO(2)). These data suggest that decreases in Pet(CO(2)) and Pa(CO(2)) during upright posture are not solely due to increased Va but could be due to ventilation-perfusion mismatch or a redistribution of CO(2) stores. Furthermore, the reduction in Pa(CO(2)) did not fully explain the decrease in CFV throughout HUT. These data suggest that factors in addition to a reduction in Pa(CO(2)) play a role in the CBF response to orthostatic stress. PMID:16306163

  18. Dynamic of diffuse CO2 emission from Decepcion volcano, Antartica

    NASA Astrophysics Data System (ADS)

    Nolasco, D.; Padron, E.; Hernandez Perez, P. A.; Christian, F.; Kusakabe, M.; Wakita, H.

    2010-12-01

    Deception Island is a volcanic island located at the South Shetland Island off the Antartic Peninsula. It constitutes a back-arc stratovolcano with a basal diameter of ~ 30 Km, the volcano rises ~ 1400 m from the seafloor to the maximum height, Mt. Pond of 540 m above sea level and over half the island is covered by glaciers. This island has a horse-shoe shape with a large flooded caldera with a diameter of about 6x10 km and a maximum depth of 190 m. This caldera is open to the sea through a narrow channel of 500 m at Neptunes Bellows. Deception Island shows the most recent active volcanism, evidence of several eruptions since the late 18th century, and well-known eruptions in 1967, 1969 and 1970 caused serious damage to local scientific stations. The aim of this study is to estimate the CO2 emissions from the Deception volcano bay. In-situ measurements of CO2 efflux from the surface environment of Deception Bay were performed by means of a portable Non Dispersive Infrared spectrophotometer (NDIR) model LICOR Li800, following the accumulation chamber method coupled with a floating device. A total of 244 CO2 efflux measurements were performed in Deception bay in November and December, 2009. CO2 efflux values ranged from non-detectable up to 119,9 g m-2 d-1. To quantify the total CO2 emission from Deception Bay, a CO2 efflux map was constructed using sequential Gaussian simulations (sGs). Most of the studied area showed background levels of CO2 efflux (~4 g m-2 d-1), while peak levels (>20 g m-2 d-1) were mainly identified inside the Fumarole Bay, Telefon Bay and Pendulum Cove areas. The total CO2 emission from Deception Bay was estimated about 191 ± 9 t/d To study the temporal evolution of the CO2 efflux values at Fumarole bay, a two month time series of CO2 diffuse emission values was recorded by an automatic geochemical station, which was installed on December 8, 2009, which measured also soil temperature and humidity and meteorological parameters. CO2 values

  19. CO2 Utilization and Storage in Shale Gas Reservoirs

    NASA Astrophysics Data System (ADS)

    Schaef, T.; Glezakou, V.; Owen, T.; Miller, Q.; Loring, J.; Davidson, C.; McGrail, P.

    2013-12-01

    Surging natural gas production from fractured shale reservoirs and the emerging concept of utilizing anthropogenic CO2 for secondary recovery and permanent storage is driving the need for understanding fundamental mechanisms controlling gas adsorption and desorption processes, mineral volume changes, and impacts to transmissivity properties. Early estimates indicate that between 10 and 30 gigatons of CO2 storage capacity may exist in the 24 shale gas plays included in current USGS assessments. However, the adsorption of gases (CO2, CH4, and SO2) is not well understood and appears unique for individual clay minerals. Using specialized experimental techniques developed at PNNL, pure clay minerals were examined at relevant pressures and temperatures during exposure to CH4, CO2, and mixtures of CO2-SO2. Adsorbed concentrations of methane displayed a linear behavior as a function of pressure as determined by a precision quartz crystal microbalance. Acid gases produced differently shaped adsorption isotherms, depending on temperature and pressure. In the instance of kaolinite, gaseous CO2 adsorbed linearly, but in the presence of supercritical CO2, surface condensation increased significantly to a peak value before desorbing with further increases in pressure. Similarly shaped CO2 adsorption isotherms derived from natural shale samples and coal samples have been reported in the literature. Adsorption steps, determined by density functional theory calculations, showed they were energetically favorable until the first CO2 layer formed, corresponding to a density of ~0.35 g/cm3. Interlayer cation content (Ca, Mg, or Na) of montmorillonites influenced adsorbed gas concentrations. Measurements by in situ x-ray diffraction demonstrate limited CO2 diffusion into the Na-montmorillonite interlayer spacing, with structural changes related to increased hydration. Volume changes were observed when Ca or Mg saturated montmorillonites in the 1W hydration state were exposed to

  20. CO2CRC's Otway Residual Saturation and Dissolution Test: Using Reactive Ester Tracers to Determine Residual CO2 Saturation

    NASA Astrophysics Data System (ADS)

    Myers, M.; Stalker, L.; LaForce, T.; Pejcic, B.; Dyt, C.; Ho, K.; Ennis-King, J.

    2013-12-01

    Residual trapping, that is CO2 held in the rock pore space due to capillarity, is an important storage mechanism in geo-sequestration of over the short to medium term (up to 1000 years). As such residual CO2 saturation is a critical reservoir parameter for assessing the storage capacity and security of carbon capture and storage (CCS). As a component of the CO2CRC's Residual Gas Saturation and Dissolution Test at the CO2CRC Otway Project site in Victoria (Australia), we have recently tested a suite of reactive esters (triacetin, tripropionin and propylene glycol diacetate) in a single well chemical tracer test to determine residual CO2 saturation. The goal of this project was to assess and validate a suite of possible tests that could be implemented to determine residual CO2 saturation. For this test, the chemical tracers were injected with a saturated CO2/water mixture into the formation (that is already at residual CO2 saturation) where they were allowed to 'soak' for approximately 10 days allowing for the partial hydrolysis of the esters to their corresponding carboxylic acids and alcohols. Water containing the tracers was then produced from the well resulting in over 600 tracer samples over a period of 12 hours. A selection of these samples were analysed for tracer content and to establish tracer breakthrough curves. To understand the behaviour of these chemical tracers in the downhole environment containing residually trapped supercritical CO2 and formation water, it is necessary to determine the supercritical CO2/water partition coefficients. We have previously determined these in the laboratory (Myers et al., 2012) and they are used here to model the tracer behaviour and provide an estimate of the residual CO2 saturation. Two different computational simulators were used to analyse the tracer breakthrough profiles. The first is based on simple chromatographic retardation and has been used extensively in single well chemical tracer tests to determine residual

  1. A sensitivity analysis on seismic tomography data with respect to CO2 saturation of a CO2 geological sequestration field

    NASA Astrophysics Data System (ADS)

    Park, Chanho; Nguyen, Phung K. T.; Nam, Myung Jin; Kim, Jongwook

    2013-04-01

    Monitoring CO2 migration and storage in geological formations is important not only for the stability of geological sequestration of CO2 but also for efficient management of CO2 injection. Especially, geophysical methods can make in situ observation of CO2 to assess the potential leakage of CO2 and to improve reservoir description as well to monitor development of geologic discontinuity (i.e., fault, crack, joint, etc.). Geophysical monitoring can be based on wireline logging or surface surveys for well-scale monitoring (high resolution and nallow area of investigation) or basin-scale monitoring (low resolution and wide area of investigation). In the meantime, crosswell tomography can make reservoir-scale monitoring to bridge the resolution gap between well logs and surface measurements. This study focuses on reservoir-scale monitoring based on crosswell seismic tomography aiming describe details of reservoir structure and monitoring migration of reservoir fluid (water and CO2). For the monitoring, we first make a sensitivity analysis on crosswell seismic tomography data with respect to CO2 saturation. For the sensitivity analysis, Rock Physics Models (RPMs) are constructed by calculating the values of density and P and S-wave velocities of a virtual CO2 injection reservoir. Since the seismic velocity of the reservoir accordingly changes as CO2 saturation changes when the CO2 saturation is less than about 20%, while when the CO2 saturation is larger than 20%, the seismic velocity is insensitive to the change, sensitivity analysis is mainly made when CO2 saturation is less than 20%. For precise simulation of seismic tomography responses for constructed RPMs, we developed a time-domain 2D elastic modeling based on finite difference method with a staggered grid employing a boundary condition of a convolutional perfectly matched layer. We further make comparison between sensitivities of seismic tomography and surface measurements for RPMs to analysis resolution

  2. CO2 Capture with Liquid-to-Solid Absorbents: CO2 Capture Process Using Phase-Changing Absorbents

    SciTech Connect

    2010-10-01

    IMPACCT Project: GE and the University of Pittsburgh are developing a unique CO2 capture process in which a liquid absorbent, upon contact with CO2, changes into a solid phase. Once in solid form, the material can be separated and the CO2 can be released for storage by heating. Upon heating, the absorbent returns to its liquid form, where it can be reused to capture more CO2. The approach is more efficient than other solventbased processes because it avoids the heating of extraneous solvents such as water. This ultimately leads to a lower cost of CO2 capture and will lower the additional cost to produce electricity for coal-fired power plants that retrofit their facilities to include this technology.

  3. Reaction of CO2 and Carbonate Mineral in Seawater for Mitigation of CO2 and Ocean Acidity

    NASA Astrophysics Data System (ADS)

    Rau, G. H.

    2010-12-01

    A lab-scale seawater/mineral carbonate gas scrubber was found to remove up to 97% of CO2 in a simulated flue gas stream at ambient temperature and pressure, with a large fraction of this carbon ultimately converted to dissolved calcium bicarbonate. Contrary to predictions based on classical carbonate chemistry, up to 85% of the captured carbon was retained in solution, i.e., it did not degas or precipitate, even after full equilibration with air. This is because abiotic precipitation of CaCO3 from seawater is chemically inhibited up to dissolved concentrations approaching 20X supersaturation. Thus, above-ground CO2 hydration with seawater, reaction with mineral carbonate, and conversion to dissolved Ca(HCO3)2 may provide a relatively simple point-source CO2 capture and storage scheme at coastal locations. This approach is analogous to wet limestone scrubbing of flue gas that is commonly used for SO2 removal. Such low-tech CO2 mitigation could be especially relevant for retrofitting to existing coastal power plants and for deployment in the developing world, the primary source of future CO2 emissions. An electrochemically powered version of the preceding has been demonstrated for air capture of CO2. In any case, the addition of the resulting alkaline solution to the ocean would benefit marine ecosystems that are currently challenged by acidification. This is indicated by the widespread use of miniature CO2/carbonate mineral/seawater reactors in saltwater aquaria to generate alkalinity for preserving or enhancing coral and shellfish growth. Large-scale applications would thus allow use of the planet’s largest saline reservoir, the ocean, to safely and effectively store anthropogenic carbon in a form other than molecular CO2 or carbonic acid. This approach in essence hastens Nature's own very effective but slow CO2 mitigation process; carbonate mineral weathering is a major consumer of excess atmospheric CO2 and ocean acidity on geologic times scales.

  4. Effect of impurities on the corrosion behavior of CO2 transmission pipeline steel in supercritical CO2-water environments.

    PubMed

    Choi, Yoon-Seok; Nesic, Srdjan; Young, David

    2010-12-01

    The corrosion property of carbon steel was evaluated using an autoclave under CO(2)-saturated water phase and water-saturated CO(2) phase with impurities (O(2) and SO(2)) at 80 bar CO(2) and 50 °C to simulate the condition of CO(2) transmission pipeline in the carbon capture and storage (CCS) applications. The results showed that the corrosion rate of carbon steel in CO(2)-saturated water was very high and it increased with adding O(2) in the system due to the inhibition effect of O(2) on the formation of protective FeCO(3). It is noteworthy that corrosion took place in the water-saturated CO(2) phase under supercritical condition when no free water is present. The addition of O(2) increased the corrosion rates of carbon steel in water-saturated CO(2) phase. The addition of 0.8 bar SO(2) (1%) in the gas phase dramatically increased the corrosion rate of carbon steel from 0.38 to 5.6 mm/y. This then increased to more than 7 mm/y with addition of both O(2) and SO(2). SO(2) can promote the formation of iron sulfite hydrate (FeSO(3)·3H(2)O) on the steel surface which is less protective than iron carbonate (FeCO(3)), and it is further oxidized to become FeSO(4) and FeOOH when O(2) is present with SO(2) in the CO(2)-rich phase. The corrosion rates of 13Cr steel were very low compared with carbon steel in CO(2)-saturated water environments with O(2), whereas it was as high as carbon steel in a water-saturated CO(2) phase with O(2) and SO(2). PMID:21049923

  5. Numerical and analogue modelling of the propagation and dissolution of CO2 into reservoir brines: implications for CO2 sequestration

    NASA Astrophysics Data System (ADS)

    Daniels, K.; Bickle, M.; Neufeld, J. A.; Waterton, P.; Kampman, N.; Maskell, A.; Chapman, H.

    2013-12-01

    The release of carbon dioxide (CO2) and other greenhouse gases into the atmosphere is recognised as the principal cause of the current changes observed in the Earth's climate. Carbon Capture and Storage (CCS) within reservoirs is seen as a solution to combat these changes through long-term and secure geological storage of CO2. The viability of long-term storage however, is reliant on an accurate knowledge of CO2 trapping mechanisms, as well as an understanding of the effect of the injected supercritical CO2 on the reservoir formations themselves. One prospective stable trapping mechanism is the dissolution of CO2 into ambient reservoir brine. Developing a greater understanding of the flow of CO2 through reservoir rocks and the associated reactions between the host rock formation and the fluid is therefore of great importance to understanding whether a CO2 storage site will succeed. This study examines the enhanced rates of dissolution found during injection into a layered, heterogeneous formation through analogue experiments and numerical modelling. The analogue experiments are designed to approximate an enhanced oil recovery (EOR) setting and show that during fluid propagation, pore-scale viscous fingers grow and retreat. This will provide an increased surface area between the flow and the ambient reservoir fluid which is likely to enhance the dissolution of CO2 in reservoir brines. The numerical simulations provide a useful comparison with the analogue experiments and give constraints on the timescales and magnitude of CO2 dissolution and the resultant fluid-mineral reactions in a heterogeneous reservoir. The study begins to address whether the dissolution of carbonate or silicate minerals can provide the CO2 with a leakage pathway through corroded caprocks and fault seals, or help with pathway sealing.

  6. Environmental potential of the use of CO2 from alcoholic fermentation processes. The CO2-AFP strategy.

    PubMed

    Alonso-Moreno, Carlos; García-Yuste, Santiago

    2016-10-15

    A novel Carbon Dioxide Utilization (CDU) approach from a relatively minor CO2 emission source, i.e., alcoholic fermentation processes (AFP), is presented. The CO2 produced as a by-product from the AFP is estimated by examining the EtOH consumed per year reported by the World Health Organization in 2014. It is proposed that the extremely pure CO2 from the AFP is captured in NaOH solutions to produce one of the Top 10 commodities in the chemical industry, Na2CO3, as a good example of an atomic economy process. The novel CDU strategy could yield over 30.6Mt of Na2CO3 in oversaturated aqueous solution on using ca. 12.7Mt of captured CO2 and this process would consume less energy than the synthetic methodology (Solvay ammonia soda process) and would not produce low-value by-products. The quantity of Na2CO3 obtained by this strategy could represent ca. 50% of the world Na2CO3 production in one year. In terms of the green economy, the viability of the strategy is discussed according to the recommendations of the CO2Chem network, and an estimation of the CO2negative emission achieved suggests a capture of around 280.0Mt of CO2 from now to 2020 or ca. 1.9Gt from now to 2050. Finally, the results obtained for this new CDU proposal are discussed by considering different scenarios; the CO2 production in a typical winemaking corporation, the CO2 released in the most relevant wine-producing countries, and the use of CO2 from AFP as an alternative for the top Na2CO3-producing countries. PMID:27300565

  7. Multiscale observations of CO2, 13CO2, and pollutants at Four Corners for emission verification and attribution

    PubMed Central

    Lindenmaier, Rodica; Dubey, Manvendra K.; Henderson, Bradley G.; Butterfield, Zachary T.; Herman, Jay R.; Rahn, Thom; Lee, Sang-Hyun

    2014-01-01

    There is a pressing need to verify air pollutant and greenhouse gas emissions from anthropogenic fossil energy sources to enforce current and future regulations. We demonstrate the feasibility of using simultaneous remote sensing observations of column abundances of CO2, CO, and NO2 to inform and verify emission inventories. We report, to our knowledge, the first ever simultaneous column enhancements in CO2 (3–10 ppm) and NO2 (1–3 Dobson Units), and evidence of δ13CO2 depletion in an urban region with two large coal-fired power plants with distinct scrubbing technologies that have resulted in ∆NOx/∆CO2 emission ratios that differ by a factor of two. Ground-based total atmospheric column trace gas abundances change synchronously and correlate well with simultaneous in situ point measurements during plume interceptions. Emission ratios of ∆NOx/∆CO2 and ∆SO2/∆CO2 derived from in situ atmospheric observations agree with those reported by in-stack monitors. Forward simulations using in-stack emissions agree with remote column CO2 and NO2 plume observations after fine scale adjustments. Both observed and simulated column ∆NO2/∆CO2 ratios indicate that a large fraction (70–75%) of the region is polluted. We demonstrate that the column emission ratios of ∆NO2/∆CO2 can resolve changes from day-to-day variation in sources with distinct emission factors (clean and dirty power plants, urban, and fires). We apportion these sources by using NO2, SO2, and CO as signatures. Our high-frequency remote sensing observations of CO2 and coemitted pollutants offer promise for the verification of power plant emission factors and abatement technologies from ground and space. PMID:24843169

  8. Annual CO2 budget and seasonal CO2 exchange signals at a High Arctic permafrost site on Spitsbergen, Svalbard archipelago

    NASA Astrophysics Data System (ADS)

    Lüers, J.; Westermann, S.; Piel, K.; Boike, J.

    2014-01-01

    The annual variability of CO2 exchange in most ecosystems is primarily driven by the activities of plants and soil microorganisms. However, little is known about the carbon balance and its controlling factors outside the growing season in arctic regions dominated by soil freeze/thaw-processes, long-lasting snow cover, and several months of darkness. This study presents a complete annual cycle of the CO2 net ecosystem exchange (NEE) dynamics for a High Arctic tundra area on the west coast of Svalbard based on eddy-covariance flux measurements. The annual cumulative CO2 budget is close to zero grams carbon per square meter per year, but shows a very strong seasonal variability. Four major CO2 exchange seasons have been identified. (1) During summer (ground snow-free), the CO2 exchange occurs mainly as a result of biological activity, with a predominance of strong CO2 assimilation by the ecosystem. (2) The autumn (ground snow-free or partly snow-covered) is dominated by CO2 respiration as a result of biological activity. (3) In winter and spring (ground snow-covered), low but persistent CO2 release occur, overlain by considerable CO2 exchange events in both directions associated with changes of air masses and air and atmospheric CO2 pressure. (4) The snow melt season (pattern of snow-free and snow-covered areas), where both, meteorological and biological forcing, resulting in a visible carbon uptake by the high arctic ecosystem. Data related to this article are archived under: http://doi.pangaea.de/10.1594/PANGAEA.809507.

  9. Monitoring Atmospheric CO2 From Space: Challenge & Approach

    NASA Technical Reports Server (NTRS)

    Lin, Bing; Harrison, F. Wallace; Nehrir, Amin; Browell, Edward; Dobler, Jeremy; Campbell, Joel; Meadows, Byron; Obland, Michael; Kooi, Susan; Fan, Tai-Fang; Ismail, Syed

    2015-01-01

    Atmospheric CO2 is the key radiative forcing for the Earth's climate and may contribute a major part of the Earth's warming during the past 150 years. Advanced knowledge on the CO2 distributions and changes can lead considerable model improvements in predictions of the Earth's future climate. Large uncertainties in the predictions have been found for decades owing to limited CO2 observations. To obtain precise measurements of atmospheric CO2, certain challenges have to be overcome. For an example, global annual means of the CO2 are rather stable, but, have a very small increasing trend that is significant for multi-decadal long-term climate. At short time scales (a second to a few hours), regional and subcontinental gradients in the CO2 concentration are very small and only in an order of a few parts per million (ppm) compared to the mean atmospheric CO2 concentration of about 400 ppm, which requires atmospheric CO2 space monitoring systems with extremely high accuracy and precision (about 0.5 ppm or 0.125%) in spatiotemporal scales around 75 km and 10-s. It also requires a decadal-scale system stability. Furthermore, rapid changes in high latitude environments such as melting ice, snow and frozen soil, persistent thin cirrus clouds in Amazon and other tropical areas, and harsh weather conditions over Southern Ocean all increase difficulties in satellite atmospheric CO2 observations. Space lidar approaches using Integrated Path Differential Absorption (IPDA) technique are considered to be capable of obtaining precise CO2 measurements and, thus, have been proposed by various studies including the 2007 Decadal Survey (DS) of the U.S. National Research Council. This study considers to use the Intensity-Modulated Continuous-Wave (IM-CW) lidar to monitor global atmospheric CO2 distribution and variability from space. Development and demonstration of space lidar for atmospheric CO2 measurements have been made through joint adventure of NASA Langley Research Center and

  10. CO2 exsolution - challenges and opportunities in subsurface flow management

    NASA Astrophysics Data System (ADS)

    Zuo, Lin; Benson, Sally

    2014-05-01

    In geological carbon sequestration, a large amount of injected CO2 will dissolve in brine over time. Exsolution occurs when pore pressures decline and CO2 solubility in brine decreases, resulting in the formation of a separate CO2 phase. This scenario occurs in storage reservoirs by upward migration of carbonated brine, through faults, leaking boreholes or even seals, driven by a reverse pressure gradient from CO2 injection or ground water extraction. In this way, dissolved CO2 could migrate out of storage reservoirs and form a gas phase at shallower depths. This paper summarizes the results of a 4-year study regarding the implications of exsolution on storage security, including core-flood experiments, micromodel studies, and numerical simulation. Micromodel studies have shown that, different from an injected CO2 phase, where the gas remains interconnected, exsolved CO2 nucleates in various locations of a porous medium, forms disconnected bubbles and propagates by a repeated process of bubble expansion and snap-off [Zuo et al., 2013]. A good correlation between bubble size distribution and pore size distribution is observed, indicating that geometry of the pore space plays an important role in controlling the mobility of brine and exsolved CO2. Core-scale experiments demonstrate that as the exsolved gas saturation increases, the water relative permeability drops significantly and is disproportionately reduced compared to drainage relative permeability [Zuo et al., 2012]. The CO2 relative permeability remains very low, 10-5~10-3, even when the exsolved CO2 saturation increases to over 40%. Furthermore, during imbibition with CO2 saturated brines, CO2 remains trapped even under relatively high capillary numbers (uv/σ~10-6) [Zuo et al., submitted]. The water relative permeability at the imbibition endpoint is 1/3~1/2 of that with carbonated water displacing injected CO2. Based on the experimental evidence, CO2 exsolution does not appear to create significant risks

  11. CO2-Selective Nanoporous Metal-Organic Framework Microcantilevers

    PubMed Central

    Yim, Changyong; Lee, Moonchan; Yun, Minhyuk; Kim, Gook-Hee; Kim, Kyong Tae; Jeon, Sangmin

    2015-01-01

    Nanoporous anodic aluminum oxide (AAO) microcantilevers are fabricated and MIL-53 (Al) metal-organic framework (MOF) layers are directly synthesized on each cantilever surface by using the aluminum oxide as the metal ion source. Exposure of the MIL53-AAO cantilevers to various concentrations of CO2, N2, CO, and Ar induces changes in their deflections and resonance frequencies. The results of the resonance frequency measurements for the different adsorbed gas molecules are almost identical when the frequency changes are normalized by the molecular weights of the gases. In contrast, the deflection measurements show that only CO2 adsorption induces substantial bending of the MIL53-AAO cantilevers. This selective deflection of the cantilevers is attributed to the strong interactions between CO2 and the hydroxyl groups in MIL-53, which induce structural changes in the MIL-53 layers. Simultaneous measurements of the resonance frequency and the deflection are performed to show that the diffusion of CO2 into the nanoporous MIL-53 layers occurs very rapidly, whereas the binding of CO2 to hydroxyl groups occurs relatively slowly, which indicates that the adsorption of CO2 onto the MIL-53 layers and the desorption of CO2 from the MIL-53 layers are reaction limited. PMID:26035805

  12. High pressure studies on extended phases of CO2

    NASA Astrophysics Data System (ADS)

    Montoya, Javier A.; Lee, Mal-Soon; Scandolo, Sandro

    2010-03-01

    Recent findings have shown that the chemistry of CO2 at high pressure and temperature is richer than previously thought and that the activation of the C=O bond that can give origin to different forms of non-molecular CO2. Such findings may have important implications for the understanding of the Earth's deep carbon cycle and CO2 sequestration technologies. First principles simulations of CO2's electronic properties under different pressure and temperature conditions can constrain the thermodynamic phase diagram of CO2 and explore P-T conditions necessary for the C=O bond activation. We have shown that at about 50 GPa molecular CO2 can transform to a metastable amorphous form characterized by an almost equal proportion of three- and four-fold coordinated carbon atoms [1], while higher carbon coordination does not take place up to at least 900 GPa [2-3]. We have also found that doping with transition metals can reduce the activation barrier and transition pressure for the C=O bond activation in CO2 [4]. Our results suggest that pressure can radically alter the oxidation chemistry of carbon. [1] J. A. Montoya et al., PRL 100, 163002 (2008) [2] J. Sun et al., PNAS 106, 6077 (2009) [3] M-S. Lee, J. A. Montoya and S. Scandolo, PRB 79, 144102 (2009) [4] J. A. Montoya, R. Rousseau, and S. Scandolo, unpublished.

  13. Spectroscopy Study of Ar + CO2 Plasmas in ASTRAL.

    NASA Astrophysics Data System (ADS)

    Munoz, Jorge; Boivin, Robert; Kamar, Ola; Loch, Stuart; Ballance, Connor

    2006-10-01

    A spectroscopy study of the ASTRAL (Auburn Steady sTate Research fAciLity) helicon plasma source running Ar + CO2 gas mix is presented. ASTRAL produces Ar plasmas: ne = 10^10 to 10^13 cm-3, Te = 2 to 10 eV and Ti = 0.03 to 0.5 eV. A series of 7 large coils produce an axial magnetic field up to 1.3 kGauss. A fractional helix antenna is used to introduce rf power up to 2 kWatt. A spectrometer which features a 0.33 m Criss-Cross monochromator and a CCD camera is used for this study. Very different plasmas are produced following the relative importance of CO2 in the gas mixture. At low CO2 concentration, the plasmas are similar to those obtained with pure Ar with weak CO2, CO2^+, CO and CO^+ bands. The usual blue plasma core associated with intense Ar II transitions is observed with however a significant white glow coming from the outer plasma regions. At higher CO2 concentration, the plasma becomes essentially molecular and can be described as an intense white plasma column. Molecular dissociative processes associated with the production of strong C and O atomic lines are observed under specific plasma conditions. The atomic spectral lines are compared with ADAS modeling results. This study indicates the possible advantages of using a helicon source to control the CO2 plasma chemistry for industrial applications.

  14. The Leakage Risk Monetization Model for Geologic CO2 Storage.

    PubMed

    Bielicki, Jeffrey M; Pollak, Melisa F; Deng, Hang; Wilson, Elizabeth J; Fitts, Jeffrey P; Peters, Catherine A

    2016-05-17

    We developed the Leakage Risk Monetization Model (LRiMM) which integrates simulation of CO2 leakage from geologic CO2 storage reservoirs with estimation of monetized leakage risk (MLR). Using geospatial data, LRiMM quantifies financial responsibility if leaked CO2 or brine interferes with subsurface resources, and estimates the MLR reduction achievable by remediating leaks. We demonstrate LRiMM with simulations of 30 years of injection into the Mt. Simon sandstone at two locations that differ primarily in their proximity to existing wells that could be leakage pathways. The peak MLR for the site nearest the leakage pathways ($7.5/tCO2) was 190x larger than for the farther injection site, illustrating how careful siting would minimize MLR in heavily used sedimentary basins. Our MLR projections are at least an order of magnitude below overall CO2 storage costs at well-sited locations, but some stakeholders may incur substantial costs. Reliable methods to detect and remediate leaks could further minimize MLR. For both sites, the risk of CO2 migrating to potable aquifers or reaching the atmosphere was negligible due to secondary trapping, whereby multiple impervious sedimentary layers trap CO2 that has leaked through the primary seal of the storage formation. PMID:27052112

  15. Combustion-Assisted CO2 Capture Using MECC Membranes

    SciTech Connect

    Sherman, Steven R; Gray, Dr. Joshua R.; Brinkman, Dr. Kyle S.; Huang, Dr. Kevin

    2012-01-01

    Mixed Electron and Carbonate ion Conductor (MECC) membranes have been proposed as a means to separate CO2 from power plant flue gas. Here a modified MECC CO2 capture process is analyzed that supplements retentate pressurization and permeate evacuation as a means to create a CO2 driving force with a process assisted by the catalytic combustion of syngas on the permeate side of the membrane. The combustion reactions consume transported oxygen, making it unavailable for the backwards transport reaction. With this change, the MECC capture system becomes exothermic, and steam for electricity production may be generated from the waste heat. Greater than 90% of the CO2 in the flue gas may be captured, and a compressed CO2 product stream is produced. A fossil-fueled power plant using this process would consume 14% more fuel per unit electricity produced than a power plant with no CO2 capture system, and has the potential to meet U.S. DOE s goal that deployment of a CO2 capture system at a fossil-fueled power plant should not increase the cost of electricity from the combined facility by more than 30%.

  16. The Nanoscale Basis of CO2 Trapping for Geologic Storage.

    PubMed

    Bourg, Ian C; Beckingham, Lauren E; DePaolo, Donald J

    2015-09-01

    Carbon capture and storage (CCS) is likely to be a critical technology to achieve large reductions in global carbon emissions over the next century. Research on the subsurface storage of CO2 is aimed at reducing uncertainties in the efficacy of CO2 storage in sedimentary rock formations. Three key parameters that have a nanoscale basis and that contribute uncertainty to predictions of CO2 trapping are the vertical permeability kv of seals, the residual CO2 saturation Sg,r in reservoir rocks, and the reactive surface area ar of silicate minerals. This review summarizes recent progress and identifies outstanding research needs in these areas. Available data suggest that the permeability of shale and mudstone seals is heavily dependent on clay fraction and can be extremely low even in the presence of fractures. Investigations of residual CO2 trapping indicate that CO2-induced alteration in the wettability of mineral surfaces may significantly influence Sg,r. Ultimately, the rate and extent of CO2 conversion to mineral phases are uncertain due to a poor understanding of the kinetics of slow reactions between minerals and fluids. Rapidly improving characterization techniques using X-rays and neutrons, and computing capability for simulating chemical interactions, provide promise for important advances. PMID:26266820

  17. The unstable CO2 feedback cycle on ocean planets

    NASA Astrophysics Data System (ADS)

    Kitzmann, Daniel; Alibert, Yann; Godolt, Mareike; Grenfell, John Lee; Heng, Kevin; Patzer, Beate; Rauer, Heike; Stracke, Barbara; von Paris, Philip

    2015-12-01

    Ocean planets are volatile rich planets, not present in our Solar System, which are dominated by deep, global oceans. Theoretical considerations and planet formation modeling studies suggest that extrasolar ocean planets should be a very common type of planet. One might therefore expect that low-mass ocean planets would be ideal candidates when searching for habitable exoplanets, since water is considered to be an essential requirement for life. However, a very large global ocean can also strongly influence the climate.The high pressure at the oceans bottom results in the formation of high-pressure water ice, separating the planetary crust from the liquid ocean and, thus, also from the atmosphere. In our study we, therefore, focus on the CO2 cycle between the atmosphere and the ocean which determines the atmospheric CO2 content. The atmospheric amount of CO2 is a fundamental quantity for assessing the potential habitability of the planet's surface because of its strong greenhouse effect, which determines the planetary surface temperature to a large degree.In contrast to the stabilising carbonate-silicate cycle regulating the long-term CO2 inventory of the Earth atmosphere, we find that the CO2 cycle on ocean planets is positive and has strong destabilising effects on the planetary climate. By using a chemistry model for oceanic CO2 dissolution and an atmospheric model for exoplanets, we show that the CO2 feedback cycle is severely limiting the potential habitability of ocean planets.

  18. Low CO2 Prevents Nitrate Reduction in Leaves 1

    PubMed Central

    Kaiser, Werner M.; Förster, Jutta

    1989-01-01

    The correlation between CO2 assimilation and nitrate reduction in detached spinach (Spinacia oleracea L.) leaves was examined by measuring light-dependent changes in leaf nitrate levels in response to mild water stress and to artificially imposed CO2 deficiency. The level of extractable nitrate reductase (NR) activity was also measured. The results are: (a) In the light, detached turgid spinach leaves reduced nitrate stored in the vacuoles of mesophyll cells at rates between 3 and 10 micromoles per milligram of chlorophyll per hour. Nitrate fed through the petiole was reduced at similar rates as storage nitrate. Nitrate reduction was accompanied by malate accumulation. (b) Under mild water stress which caused stomatal closure, nitrate reduction was prevented. The inhibition of nitrate reduction observed in water stressed leaves was reversed by external CO2 concentrations (10-15%) high enough to overcome stomatal resistance. (c) Nitrate reduction was also inhibited when turgid leaves were kept in CO2-free air or at the CO2-compensation point or in nitrogen. (d) When leaves were illuminated in CO2-free air, activity of NR decreased rapidly. It increased again, when CO2 was added back to the system. The half-time for a 50% change in activity was about 30 min. It thus appears that there is a rapid inactivation/activation mechanism of NR in leaves which couples nitrate reductase to net photosynthesis. PMID:16667163

  19. Performance of CO2 enrich CNG in direct injection engine

    NASA Astrophysics Data System (ADS)

    Firmansyah, W. B.; Ayandotun, E. Z.; Zainal, A.; Aziz, A. R. A.; Heika, M. R.

    2015-12-01

    This paper investigates the potential of utilizing the undeveloped natural gas fields in Malaysia with high carbon dioxide (CO2) content ranging from 28% to 87%. For this experiment, various CO2 proportions by volume were added to pure natural gas as a way of simulating raw natural gas compositions in these fields. The experimental tests were carried out using a 4-stroke single cylinder spark ignition (SI) direct injection (DI) compressed natural gas (CNG) engine. The tests were carried out at 180° and 300° before top dead centre (BTDC) injection timing at 3000 rpm, to establish the effects on the engine performance. The results show that CO2 is suppressing the combustion of CNG while on the other hand CNG combustion is causing CO2 dissociation shown by decreasing CO2 emission with the increase in CO2 content. Results for 180° BTDC injection timing shows higher performance compared to 300° BTDC because of two possible reasons, higher volumetric efficiency and higher stratification level. The results also showed the possibility of increasing the CO2 content by injection strategy.

  20. CO2 mitigation via capture and chemical conversion in seawater.

    PubMed

    Rau, Greg H

    2011-02-01

    A lab-scale seawater/mineral carbonate gas scrubber was found to remove up to 97% of CO(2) in a simulated flue gas stream at ambient temperature and pressure, with a large fraction of this carbon ultimately converted to dissolved calcium bicarbonate. After full equilibration with air, up to 85% of the captured carbon was retained in solution, that is, it did not degas or precipitate. Thus, above-ground CO(2) hydration and mineral carbonate scrubbing may provide a relatively simple point-source CO(2) capture and storage scheme at coastal locations. Such low-tech CO(2) mitigation could be especially relevant for retrofitting to existing power plants and for deployment in the developing world, the primary source of future CO(2) emissions. Addition of the resulting alkaline solution to the ocean may benefit marine ecosystems that are currently threatened by acidification, while also allowing the utilization of the vast potential of the sea to safely sequester anthropogenic carbon. This approach in essence hastens Nature's own very effective but slow CO(2) mitigation process; carbonate mineral weathering is a major consumer of excess atmospheric CO(2) and ocean acidity on geologic times scales. PMID:21189009

  1. Tropical epiphytes in a CO 2-rich atmosphere

    NASA Astrophysics Data System (ADS)

    Monteiro, José Alberto Fernandez; Zotz, Gerhard; Körner, Christian

    2009-01-01

    We tested the effect on epiphyte growth of a doubling of pre-industrial CO 2 concentration (280 vs. 560 ppm) combined with two light (three fold) and two nutrition (ten fold) treatments under close to natural humid conditions in daylight growth cabinets over 6 months. Across co-treatments and six species, elevated CO 2 increased relative growth rates by only 6% ( p = 0.03). Although the three C3 species, on average, grew 60% faster than the three CAM species, the two groups did not significantly differ in their CO 2 response. The two Orchidaceae, Bulbophyllum (CAM) and Oncidium (C3) showed no CO 2 response, and three out of four Bromeliaceae showed a positive one: Aechmea (CAM, +32% p = 0.08), Catopsis (C3, +11% p = 0.01) and Vriesea (C3, +4% p = 0.02). In contrast, the representative of the species-rich genus Tillandsia (CAM), which grew very well under experimental conditions, showed no stimulation. On average, high light increased growth by 21% and high nutrients by 10%. Interactions between CO 2, light and nutrient treatments (low vs. high) were inconsistent across species. CO 2 responsive taxa such as Catopsis, could accelerate tropical forest dynamics and increase branch breakage, but overall, the responses to doubling CO 2 of these epiphytes was relatively small and the responses were taxa specific.

  2. Clinical effects of CO2 laser on equine diseases

    NASA Astrophysics Data System (ADS)

    Lindholm, Arne; Svensson, Ulf; Collinder, Eje

    2002-10-01

    CO2 lasers has been used for five years at Malaren Equine Hospital, as an alternative treatment of some equine diseases. The application of CO2 laser has been studied for evaluation of its appropriateness for treatment of the equine diseases sarcoids, lameness in fetlock joints or pulmonary haemorrhage. During the last five years, above 100 equine sarcoids have been removed by laser surgery (CO2 laser) and so far resulting in significantly few recurrences compared with results from usual excision surgery. In one study, acute traumatic arthritis in fetlock joints was treated three times every second day with defocalised CO2 laser. The therapeutic effectiveness of CO2 laser in this study was better than that of the customary therapy with betamethasone plus hyaluronan. During one year, chronic pulmonary bleeders, namely exercise induced pulmonary haemorrhage, has been treated with defocalised CO2 laser. Six race horses have been treated once daily during five days. Until now, three of these horses have subsequently been successfully racing and no symptoms of pulmonary haemorrhage have been observed. These studies indicate that CO2 laser might be an appropriate therapy on sarcoids and traumatic arthritis, and probably also on exercise induced pulmonary haemorrhage. Other treatments for this pulmonary disease are few.

  3. CO2 fluxes near a forest edge: a numerical study.

    PubMed

    Sogachev, Andrey; Leclerc, Monique Y; Zhang, Gengsheng; Rannik, Ullar; Vesala, Timo

    2008-09-01

    In contrast with recent advances on the dynamics of the flow at a forest edge, few studies have considered its role on scalar transport and, in particular, on CO2 transfer. The present study addresses the influence of the abrupt roughness change on forest atmosphere CO2 exchange and contrasts the concentration and flux fields against those of a uniform forested surface. We use an atmospheric boundary layer two-equation closure model that accounts for the flow dynamics and vertical divergence of CO2 sources/sinks within a plant canopy. This paper characterizes the spatial variation of CO2 fluxes as a function of both sources/sinks distribution and the vertical structure of the canopy. Results suggest that the ground source plays a major role in the formation of wave-like vertical CO2 flux behavior downwind of a forest edge, despite the fact that the contribution of foliage sources/sinks changes monotonously. Such a variation is caused by scalar advection in the trunk space and reveals itself as a decrease or increase in vertical fluxes over the forest relative to carbon dioxide exchange of the underlying forest. The effect was more pronounced in model forests where the leaf area is concentrated in the upper part of the canopy. These results can be useful both for interpretation of existing measurements of net ecosystem exchange of CO2 (NEE) from flux towers in limited fetch conditions and in planning future CO2 transport experiments. PMID:18767622

  4. Isentropic transport and the seasonal cycle amplitude of CO2

    NASA Astrophysics Data System (ADS)

    Barnes, Elizabeth A.; Parazoo, Nicholas; Orbe, Clara; Denning, A. Scott

    2016-07-01

    Carbon-concentration feedbacks and carbon-climate feedbacks constitute one of the largest sources of uncertainty in future climate. Since the beginning of the modern atmospheric CO2 record, seasonal variations in CO2 have been recognized as a signal of the metabolism of land ecosystems, and quantitative attribution of changes in the seasonal cycle amplitude (SCA) of CO2 to ecosystem processes is critical for understanding and projecting carbon-climate feedbacks far into the 21st Century. Here the impact of surface carbon fluxes on the SCA of CO2 throughout the Northern Hemisphere troposphere is investigated, paying particular attention to isentropic transport across latitudes. The analysis includes both a chemical transport model GOES-Chem and an idealized tracer in a gray-radiation aquaplanet. The results of the study can be summarized by two main conclusions: (1) the SCA of CO2 roughly follows surfaces of constant potential temperature, which can explain the observed increase in SCA with latitude along pressure surfaces and (2) increasing seasonal fluxes in lower latitudes have a larger impact on the SCA of CO2 throughout most of the troposphere compared to increasing seasonal fluxes in higher latitudes. These results provide strong evidence that recently observed changes in the SCA of CO2 at high northern latitudes (poleward of 60°N) are likely driven by changes in midlatitude surface fluxes, rather than changes in Arctic fluxes.

  5. A role for atmospheric CO2 in preindustrial climate forcing.

    PubMed

    van Hoof, Thomas B; Wagner-Cremer, Friederike; Kürschner, Wolfram M; Visscher, Henk

    2008-10-14

    Complementary to measurements in Antarctic ice cores, stomatal frequency analysis of leaves of land plants preserved in peat and lake deposits can provide a proxy record of preindustrial atmospheric CO(2) concentration. CO(2) trends based on leaf remains of Quercus robur (English oak) from the Netherlands support the presence of significant CO(2) variability during the first half of the last millennium. The amplitude of the reconstructed multidecadal fluctuations, up to 34 parts per million by volume, considerably exceeds maximum shifts measured in Antarctic ice. Inferred changes in CO(2) radiative forcing are of a magnitude similar to variations ascribed to other mechanisms, particularly solar irradiance and volcanic activity, and may therefore call into question the concept of the Intergovernmental Panel on Climate Change, which assumes an insignificant role of CO(2) as a preindustrial climate-forcing factor. The stomata-based CO(2) trends correlate with coeval sea-surface temperature trends in the North Atlantic Ocean, suggesting the possibility of an oceanic source/sink mechanism for the recorded CO(2) changes. PMID:18838689

  6. CO2 photodissociation and vibrational excitation in the planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Slanger, T. G.

    1974-01-01