WorldWideScience

Sample records for plains co2 reduction

  1. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2004-10-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) by providing information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. Task 5 focused on screening and qualitatively assessing sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  2. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2005-01-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) by providing information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. Task 5 focused on screening and qualitatively assessing sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  3. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2005-01-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) by providing information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. Task 5 focused on screening and qualitatively assessing sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  4. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Lisa S. Botnen

    2005-07-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership characterization work is nearing completion, and most remaining efforts are related to finalizing work products. Task 2 (Technology Deployment) has developed a Topical Report entitled ''Deployment Issues Related to Geologic CO{sub 2} Sequestration in the PCOR Partnership Region''. Task 3 (Public Outreach) has developed an informational Public Television program entitled ''Nature in the Balance'', about CO{sub 2} sequestration. The program was completed and aired on Prairie Public Television in this quarter. Task 4 (Sources, Sinks, and Infrastructure) efforts are nearing completion, and data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation are being incorporated into a series of topical reports. The expansion of the Decision Support System Geographic Information System database has continued with the development of a ''save bookmark'' feature that allows users to save a map from the system easily. A feature that allows users to develop a report that summarizes CO{sub 2} sequestration parameters was also developed. Task 5 (Modeling and Phase II Action Plans) focused on screening and qualitatively assessing sequestration options and developing economic estimates for important regional CO{sub 2} sequestration strategies.

  5. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2005-04-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) and provided information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 2 efforts also included preparation of a draft topical report entitled ''Deployment Issues Related to Geologic CO{sub 2} Sequestration in the PCOR Partnership Region'', which is nearing completion. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. The video will be completed and aired on Prairie Public Television in the next quarter. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. The addition of the Canadian province of Alberta to the PCOR Partnership region expanded the decision support system (DSS) geographic information system database. Task 5 screened and qualitatively assessed sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  6. PLAINS CO2 REDUCTION (PCOR) PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. CO2 reduction strategies for the Northern Netherlands

    NARCIS (Netherlands)

    Benders, Rene; Moll, Henk; Noorman, Klaas Jan; Wiersma, Gerwin

    2011-01-01

    The concern about global warming initiated ambitious CO2 reduction goals in cities and regions in the Netherlands. This article describes a study of such a local initiative for the Northern Netherlands. The research aimed to develop CO2 reduction scenarios for 2035 with national and international

  8. CO2 reduction using adsorption followed by nonthermal plasma treatment

    Science.gov (United States)

    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%.

  9. Bifunctional Catalysts for CO2 Reduction

    Science.gov (United States)

    2014-09-30

    dioxide reduction catalysis . (SA 1 – Catalyst candidate synthesis) As outlined in the original proposal, ligand platforms have been synthesized to...was limited to outer-sphere electron transfer (necessary oxidation potentials for catalysis > –2.1 V vs. [Cp2Fe] +/0). Thus, we pursued two...to heterogeneous Fischer-Tropsch13 catalysts. This reactivity must also be compared with mononuclear early transition metal ligands that require

  10. CuZn Alloy- Based Electrocatalyst for CO2 Reduction

    KAUST Repository

    Alazmi, Amira

    2014-06-01

    ABSTRACT CuZn Alloy- Based Electrocatalyst for CO2 Reduction Amira Alazmi Carbon dioxide (CO2) is one of the major greenhouse gases and its emission is a significant threat to global economy and sustainability. Efficient CO2 conversion leads to utilization of CO2 as a carbon feedstock, but activating the most stable carbon-based molecule, CO2, is a challenging task. Electrochemical conversion of CO2 is considered to be the beneficial approach to generate carbon-containing fuels directly from CO2, especially when the electronic energy is derived from renewable energies, such as solar, wind, geo-thermal and tidal. To achieve this goal, the development of an efficient electrocatalyst for CO2 reduction is essential. In this thesis, studies on CuZn alloys with heat treatments at different temperatures have been evaluated as electrocatalysts for CO2 reduction. It was found that the catalytic activity of these electrodes was strongly dependent on the thermal oxidation temperature before their use for electrochemical measurements. The polycrystalline CuZn electrode without thermal treatment shows the Faradaic efficiency for CO formation of only 30% at applied potential ~−1.0 V vs. RHE with current density of ~−2.55 mA cm−2. In contrast, the reduction of oxide-based CuZn alloy electrode exhibits 65% Faradaic efficiency for CO at lower applied potential about −1.0 V vs. RHE with current density of −2.55 mA cm−2. Furthermore, stable activity was achieved over several hours of the reduction reaction at the modified electrodes. Based on electrokinetic studies, this improvement could be attributed to further stabilization of the CO2•− on the oxide-based Cu-Zn alloy surface.

  11. Towards Artificial Photosynthesis: Photoelectrochemical CO2 Reduction to Solar Fuels

    OpenAIRE

    Parra Puerto, Andrés

    2015-01-01

    This thesis is devoted to prove the concept of the CO(2) reduction to CH(4) with a decreasing in the voltage requirements using a photocatalytic mechanism. Subsequently, part of the solar energy is transferred to the reaction, obtaining an improvement in the total energy balance. The work developed intends first, to take advantage of the know features of the photoactive nanostructured materials obtained by anodization and hydrothermal synthesis (allowing to obtain better surface areas and imp...

  12. Reinforced photocatalytic reduction of CO2 to CO by a ternary metal oxide NiCo2O4.

    Science.gov (United States)

    Wang, Zhaoyu; Jiang, Min; Qin, Jiani; Zhou, Han; Ding, Zhengxin

    2015-06-28

    The work reported herein was the facile preparation of uniform urchin-like NiCo2O4 microspheres, and their use as an efficient and stable cocatalyst for photocatalytic CO2 reduction catalysis. A combined solvothermal-calcination strategy was applied to synthesize the NiCo2O4 material that was systematically characterized by physical and chemical measurements (e.g. SEM, TEM, XRD, XPS, EDX, elemental mapping and N2 physisorption analysis). By cooperation with a visible light photosensitizer, the NiCo2O4 material effectively promoted the deoxygenative reduction of CO2 to CO by more than twenty times under mild reaction conditions. The carbon origin of CO evolution was validated by (13)CO2 isotope tracer experiments. Various reaction parameters were examined and optimized, and a possible reaction mechanism was proposed. Furthermore, the stability and reusability of NiCo2O4 cocatalysts were firmly confirmed.

  13. A Market value for CO2 reductions in the non-industrial sectors.

    NARCIS (Netherlands)

    Blacquiere, Douwe

    2007-01-01

    CO2 emissions from human activities contribute to climate change. To limit climate change and its consequences, governments set ambitious targets for reduction of greenhouse gasses such as CO2. The Netherlands aims at a 30% reduction of greenhouse gasses

  14. Throwing new light on the reduction of CO2.

    Science.gov (United States)

    Ozin, Geoffrey A

    2015-03-18

    While the chemical energy in fossil fuels has enabled the rapid rise of modern civilization, their utilization and accompanying anthropogenic CO2 emissions is occurring at a rate that is outpacing nature's carbon cycle. Its effect is now considered to be irreversible and this could lead to the demise of human society. This is a complex issue without a single solution, yet from the burgeoning global research activity and development in the field of CO2 capture and utilization, there is light at the end of the tunnel. In this article a couple of recent advances are illuminated. Attention is focused on the discovery of gas-phase, light-assisted heterogeneous catalytic materials and processes for CO2 photoreduction that operate at sufficiently high rates and conversion efficiencies, and under mild conditions, to open a new pathway for an energy transition from today's "fossil fuel economy" to a new and sustainable "CO2 economy". Whichever of the competing CO2 capture and utilization approaches proves to be the best way forward for the development of a future CO2-based solar fuels economy, hopefully this can occur in a period short enough to circumvent the predicted adverse consequences of greenhouse gas climate change.

  15. Surface modification and enhanced photocatalytic CO2 reduction performance of TiO2: a review

    Science.gov (United States)

    Low, Jingxiang; Cheng, Bei; Yu, Jiaguo

    2017-01-01

    Recently, the excessive consumption of fossil fuels has caused high emissions of the greenhouse gases, CO2 into atmosphere and global energy crisis. Mimicking the natural photosynthesis by using semiconductor materials to achieve photocatalytic CO2 reduction into valuable solar fuels such as CH4, HCO2H, CH2O, and CH3OH is known as one of the best solutions for addressing the aforementioned issue. Among various proposed photocatalysts, TiO2 has been extensively studied over the past several decades for photocatalytic CO2 reduction because of its cheapness and environmental friendliness. Particularly, surface modification of TiO2 has attracted numerous interests due to its capability of enhancing the light absorption ability, facilitating the electron-hole separation, tuning the CO2 reduction selectivity and increasing the CO2 adsorption and activation ability of TiO2 for photocatalytic CO2 reduction. In this review, recent approaches of the surface modification of TiO2 for photocatalytic CO2 reduction, including impurity doping, metal deposition, alkali modification, heterojunction construction and carbon-based material loading, are presented. The photocatalytic CO2 reduction mechanism and pathways of TiO2 are discussed. The future research direction and perspective of photocatalytic CO2 reduction over surface-modified TiO2 are also presented.

  16. Kinetics of CO2 reduction in KOH/methanol electrolyte on Pb electrode

    Institute of Scientific and Technical Information of China (English)

    SONG Shuang; HE Zhi-qiao; YE Jie-xu; CHEN Jian-meng

    2007-01-01

    The electrochemical reduction of CO2 on a Pb electrode was investigated in 0.1 mol/L KOH/methanol electrolyte at different temperatures and pressures. A graphite electrode was employed as the counter electrode, and an AglAgCl ( sat. KCl) electrode was used as the reference electrode. The Tafel plots of the products by the electrochemical reduction of CO2 showed that the formation process of HCOOH differed from that of CO and the reduction of CO2 was not limited by the diffusion of CO2 in the investigated potential range. Kinetic analysis indicated that the reaction orders were 0.573 for electrochemical reduction of CO2 to CO and 0. 671 for CO2 to HCOOH in the cathodic direction.

  17. Estimating the Reduction of Generating System CO2 Emissions Resulting from Significant Wind Energy Penetration

    Energy Technology Data Exchange (ETDEWEB)

    Holttinen, Hannele; Kiviluoma, Juha; Pineda, Ivan; McCann, John; Clancy, Matthew; Milligan, Michael

    2014-11-13

    This paper presents ways of estimating CO2 reductions of wind power using different methodologies. The paper discusses pitfalls in methodology and proposes appropriate methods to perform the calculations. Results for CO2 emission reductions are shown from several countries. This paper is an international collaboration of IEA Wind Task 25 on wind integration.

  18. Reduction of CO2 Emissions Due to Wind Energy - Methods and Issues in Estimating Operational Emission Reductions

    Energy Technology Data Exchange (ETDEWEB)

    Holttinen, Hannele; Kiviluoma, Juha; McCann, John; Clancy, Matthew; Millgan, Michael; Pineda, Ivan; Eriksen, Peter Borre; Orths, Antje; Wolfgang, Ove

    2015-10-05

    This paper presents ways of estimating CO2 reductions of wind power using different methodologies. Estimates based on historical data have more pitfalls in methodology than estimates based on dispatch simulations. Taking into account exchange of electricity with neighboring regions is challenging for all methods. Results for CO2 emission reductions are shown from several countries. Wind power will reduce emissions for about 0.3-0.4 MtCO2/MWh when replacing mainly gas and up to 0.7 MtCO2/MWh when replacing mainly coal powered generation. The paper focuses on CO2 emissions from power system operation phase, but long term impacts are shortly discussed.

  19. Reduction of CO2 and orbital debris: can CO2 emission trading principles be applied to debris reduction?

    Science.gov (United States)

    Orlando, Giovanni; Kinnersley, Mark; Starke, Juergen; Hugel, Sebastian; Hartner, Gloria; Singh, Sanjay; Loubiere, Vincent; Staebler, Dominik-Markus; O'Brien-Organ, Christopher; Schwindt, Stefan; Serreau, Francois; Sharma, Mohit

    In the past years global pollution and the specific situation of global warming changes have been strongly influencing public opinion and thus obliged politicians to initiate/ negotiate in-ternational agreements to control, avoid or at least reduce the impact of CO2 emissions e.g. The Kyoto Protocol (1997) and the International Copenhagen conference on Climate Change (2009). In the orbital debris area the collision between the Iridium33 and Cosmos 2251 satel-lites in 2009 has again pushed to the forefront the discussion of the space pollution by space debris and the increasing risk of critical and catastrophic events during the nominal life time of space objects. It is shown by simulations that for Low Earth Orbits the critical debris situation is already achieved and the existing space objects will probably produce sufficient space debris elements -big enough -to support the cascade effect (Kessler Syndrome). In anal-ogy with CO2 emissions, potential recommendations / regulations to reduce the production of Space Debris or its permanence in orbit, are likely to open new markets involving Miti-gation and Removal of Space Debris. The principle approach for the CO2 emission trading model will be investigated and the applicability for the global space debris handling will be analysed. The major differences of the two markets will be derived and the consequences in-dicated. Potential alternative solutions will be proposed and discussed. For the example of the CO2 emission trading principles within EU and worldwide legal conditions for space debris (national / international laws and recommendations) will be considered as well as the commer-cial approach from the controlled situation of dedicated orders to a free / competitive market in steps. It is of interest to consider forms of potential industrial organisations and interna-tional co-operations to react on a similar architecture for the debris removal trading including incentives and penalties for the different

  20. Nanostructured Materials for Heterogeneous Electrocatalytic CO2 Reduction and Related Reaction Mechanisms.

    Science.gov (United States)

    Gong, Jinlong; Zhang, Lei; Zhao, Zhi-Jian

    2017-02-06

    The gradually increased concentration of carbon dioxide (CO2) in the atmosphere has been recognized as the primary culprit for the raise of the global mean temperature, thus resulting in the aggravated desert formation and extinction of species. In recent years, development of the routes for highly efficient conversion of CO2 has received numerous attentions. Among them, the reduction of CO2 with electric power is an important transformation route with high application prospect, due to its high environmental compatibility and good combination with other renewable energy sources such as solar and wind energy. This review describes recent progress on the design and synthesis of solid state catalysts (i.e., heterogeneous catalysts) and their emerging catalytic performances in the CO2 reduction. The significance for catalytic conversion of CO2 and the advantages of CO2 electroreduction will be presented in the introduction section, followed by the general parameters for CO2 electroreduction and the summary of reaction apparatus. We also discuss various types of solid catalysts according to CO2 conversion mechanisms. Furthermore, we summarize the crucial factors (particle size, surface structure, composition and etc.) determining the performance for electroreduction. These studies in improvement of solid state catalysts for CO2 reduction offer numerous experiences for developing potential industrialized CO2 electroreduction catalysts in the future. Additionally, the abundant experience for controllable synthesis of solid state catalysts could effectively guide the rational design of catalysts for other electrocatalytic reactions.

  1. Recent progress and perspectives in the photocatalytic CO2 reduction of Ti-oxide-based nanomaterials

    Science.gov (United States)

    Sohn, Youngku; Huang, Weixin; Taghipour, Fariborz

    2017-02-01

    The conversion of CO2 with H2O to valuable chemicals and fuels is a new solution to current environmental and energy problems, and the high energy barrier of these reactions can be overcome by the input of solar and electrical energy. However, the reduction efficiencies and selectivities of these reactions are insufficient for practical use, and significant effort and strategy are required to overcome the many obstacles preventing the large-scale application of photocatalytic CO2 reduction. This article reviews recent progress in CO2 reduction using titanium oxide-based materials and various strategic factors for increasing photocatalytic efficiency. This article also highlights non-titanium-oxide catalysts, the photoelectrocatalytic reduction of CO2, and other recent review articles concerning the recycling of CO2 to value-added carbon compounds.

  2. Toward Solar-Driven Photocatalytic CO2 Reduction Using Water as an Electron Donor.

    Science.gov (United States)

    Sato, Shunsuke; Arai, Takeo; Morikawa, Takeshi

    2015-06-01

    Developing a system for the production of organic chemicals via CO2 reduction is an important area of research that has the potential to address global warming and fossil fuel consumption. In addition, CO2 reduction promotes carbon source recycling. Solar energy is the largest exploitable resource among renewable energy resources, providing more energy to Earth per hour than the total energy consumed by humans in 1 year. This report describes the advantages and disadvantages of the available CO2 reduction and H2O oxidation photocatalysts and the conjugation of photocatalytic CO2 reduction with H2O oxidation for the creation of an artificial photosynthesis system. In this system, CO2 photoreduction and H2O photooxidation proceeded simultaneously within one system under sunlight irradiation using a hybrid of semiconductors and molecular metal-complex catalysts.

  3. Controlled electropolymerisation of a carbazole-functionalised iron porphyrin electrocatalyst for CO2 reduction

    DEFF Research Database (Denmark)

    Hu, Xinming; Salmi, Zakaria; Lillethorup, Mie;

    2016-01-01

    Using a one-step electropolymerisation procedure, CO2 absorbing microporous carbazole-functionalised films of iron porphyrins are prepared in a controlled manner. The electrocatalytic reduction of CO2 for these films is investigated to elucidate their efficiency and the origin of their ultimate...

  4. Ecosystem-atmosphere exchange of CO2 in a temperate herbaceous peatland in the Sanjiang Plain of northeast China

    Science.gov (United States)

    Zhu, Xiaoyan; Song, Changchun; Swarzenski, Christopher M.; Guo, Yuedong; Zhang, Xinhow; Wang, Jiaoyue

    2015-01-01

    Northern peatlands contain a considerable share of the terrestrial carbon pool, which will be affected by future climatic variability. Using the static chamber technique, we investigated ecosystem respiration and soil respiration over two growing seasons (2012 and 2013) in a Carex lasiocarpa-dominated peatland in the Sanjiang Plain in China. We synchronously monitored the environmental factors controlling CO2 fluxes. Ecosystem respiration during these two growing seasons ranged from 33.3 to 506.7 mg CO2–C m−2 h−1. Through step-wise regression, variations in soil temperature at 10 cm depth alone explained 73.7% of the observed variance in log10(ER). The mean Q10 values ranged from 2.1 to 2.9 depending on the choice of depth where soil temperature was measured. The Q10 value at the 10 cm depth (2.9) appears to be a good representation for herbaceous peatland in the Sanjiang Plain when applying field-estimation based Q10values to current terrestrial ecosystem models due to the most optimized regression coefficient (63.2%). Soil respiration amounted to 57% of ecosystem respiration and played a major role in peatland carbon balance in our study. Emphasis on ecosystem respiration from temperate peatlands in the Sanjiang Plain will improve our basic understanding of carbon exchange between peatland ecosystem and the atmosphere.

  5. PHOTOCHEMICAL CO2 REDUCTION BY RHENUIM AND RUTHENIUM COMPLEXES.

    Energy Technology Data Exchange (ETDEWEB)

    FUJITA,E.; MUCKERMAN, J.T.; TANAKA, K.

    2007-11-30

    Photochemical conversion of CO{sub 2} to fuels or useful chemicals using renewable solar energy is an attractive solution to both the world's need for fuels and the reduction of greenhouse gases. Rhenium(I) and ruthenium(II) diimine complexes have been shown to act as photocatalysts and/or electrocatalysts for CO{sub 2} reduction to CO. We have studied these photochemical systems focusing on the identification of intermediates and the bond formation/cleavage reactions between the metal center and CO{sub 2}. For example, we have produced the one-electron-reduced monomer (i.e. Re(dmb)(CO){sub 3}S where dmb = 4,4'-dimethy-2,2'-bipyridine and S = solvent) either by reductive quenching of the excited states of fac-[Re(dmb)(CO){sub 3}(CH{sub 3}CN)]PF{sub 6} or by photo-induced homolysis of [Re(dmb)(CO){sub 3}]{sub 2}. We previously found that: (1) the remarkably slow dimerization of Re(dmb)(CO){sub 3}S is due to the absence of a vacant coordination site for Re-Re bond formation, and the extra electron is located on the dmb ligand; (2) the reaction of Re(dmb)(CO){sub 3}S with CO{sub 2} forms a CO{sub 2}-bridged binuclear species (CO){sub 3}(dmb)Re-CO(O)-Re(dmb)(CO){sub 3} as an intermediate in CO formation; and (3) the kinetics and mechanism of reactions are consistent with the interaction of the CO{sub 2}-bridged binuclear species with CO{sub 2} to form CO and CO{sub 3}{sup 2-}.

  6. Reduction of CO2 emissions by reduction of paper use for publication applications

    Energy Technology Data Exchange (ETDEWEB)

    Van den Reek, J.A.

    1999-10-01

    The main research question of this study is as follows: What is the technical potential for reducing paper use in the field of publication applications in Western Europe within a time frame of 10-20 years, and what will the consequences for CO2 emissions be? To answer this central question we have defined the next four subquestions, all related to Western Europe: (1) How were the historical trends for the consumption figures of publication papers?; (2) What will be the expected publication paper consumption the next 10-20 years based on the historical trends, and what will be the influence on the related CO2 emissions?; (3) What technical opportunities do we see to reduce the future paper consumption trend for publication applications and what will be the individual and cumulative technical potential of these innovations?; (4) Does implementation of the technical opportunities lead to a significant dematerialization effect? Chapter 2 describes the chosen research method. In Chapter 3 we will introduce and define the paper types studied. Furthermore, Chapter 3 describes the detailed division of publication papers we have used in this study and the relationship with pulp and papermaking. After reading this chapter it has to be clear which paper production methods and paper types are (per ton) responsible for how much CO2 emissions. To get an overall-impression of the relevance of certain papers for CO2 emission numbers it is important to have insight into the historical consumption patterns of publication papers. Chapter 4 pays attention to these consumption patterns. Chapter 5 describes the most important trend factors that may influence future paper consumption patterns and in Chapter 6 this is translated into three possible consumption growth scenarios. The first and second growth scenarios are only based on extrapolations from historical figures, the third scenario is based on some of the most significant potential reduction measures. Furthermore, Chapter 6 gives

  7. Recommendations for autonomous underway pCO 2 measuring systems and data-reduction routines

    Science.gov (United States)

    Pierrot, Denis; Neill, Craig; Sullivan, Kevin; Castle, Robert; Wanninkhof, Rik; Lüger, Heike; Johannessen, Truls; Olsen, Are; Feely, Richard A.; Cosca, Catherine E.

    2009-04-01

    In order to facilitate the collection of high quality and uniform surface water pCO 2 data, an underway pCO 2 instrument has been designed based on community input and is now commercially available. Along with instrumentation, agreements were reached on data reduction and quality control that can be easily applied to data from these systems by using custom-made freeware. This new automated underway pCO 2 measuring system is designed to be accurate to within 0.1 μatm for atmospheric pCO 2 measurements and to within 2 μatm for seawater pCO 2, targeted by the scientific community to constrain the regional air-sea CO 2 fluxes to 0.2 Pg C year -1. The procedure to properly reduce the underway pCO 2 data and perform the steps necessary for calculation of the fugacity of CO 2 from the measurements is described. This system is now widely used by the scientific community on many different types of ships. Combined with the recommended data-reduction procedures, it will facilitate producing data sets that will significantly decrease the uncertainty currently present in estimates of air-sea CO 2 fluxes.

  8. Novel Catalytic Reactor for CO2 Reduction via Sabatier Process Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A novel short contact time Microlith Sabatier reactor system for CO2 reduction offers a significant advance in support of manned spaceflight. Compared to current and...

  9. Novel, Regenerable Microlith Catalytic Reactor for CO2 Reduction via Bosch Process Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Precision Combustion, Inc. (PCI) proposes to develop an extremely compact, lightweight and regenerable MicrolithREG catalytic CO2 reduction reactor, capable of...

  10. Stratospheric ozone response to a solar irradiance reduction in a quadrupled CO2 environment

    Science.gov (United States)

    Jackman, Charles H.; Fleming, Eric L.

    2014-07-01

    We used the Goddard Space Flight Center (GSFC) global two-dimensional (2D) atmospheric model to investigate the stratospheric ozone response to a proposed geoengineering activity wherein a reduced top-of-atmosphere (TOA) solar irradiance is imposed to help counteract a quadrupled CO2 atmosphere. This study is similar to the Geoengineering Model Intercomparison Project (GeoMIP) Experiment G1. Three primary simulations were completed with the GSFC 2D model to examine this possibility: (A) a pre-industrial atmosphere with a boundary condition of 285 ppmv CO2 (piControl); (B) a base future atmosphere with 1140 ppmv CO2 (abrupt4xCO2); and (C) a perturbed future atmosphere with 1140 ppmv CO2 and a 4% reduction in the TOA total solar irradiance (G1). We found huge ozone enhancements throughout most of the stratosphere (up to 40%) as a result of a large computed temperature decrease (up to 18 K) when CO2 was quadrupled (compare simulation abrupt4xCO2 to piControl). Further, we found that ozone will additionally increase (up to 5%) throughout most of the stratosphere with total ozone increases of 1-2.5% as a result of a reduction in TOA total solar irradiance (compare simulation G1 to abrupt4xCO2). Decreases of atomic oxygen and temperature are the main drivers of this computed ozone enhancement from a reduction in TOA total solar irradiance.

  11. Trialkylborane-Assisted CO(2) Reduction by Late Transition Metal Hydrides.

    Science.gov (United States)

    Miller, Alexander J M; Labinger, Jay A; Bercaw, John E

    2011-01-01

    Trialkylborane additives promote reduction of CO(2) to formate by bis(diphosphine) Ni(II) and Rh(III) hydride complexes. The late transition metal hydrides, which can be formed from dihydrogen, transfer hydride to CO(2) to give a formate-borane adduct. The borane must be of appropriate Lewis acidity: weaker acids do not show significant hydride transfer enhancement, while stronger acids abstract hydride without CO(2) reduction. The mechanism likely involves a pre-equilibrium hydride transfer followed by formation of a stabilizing formate-borane adduct.

  12. Potential CO2 emission reduction by development of non-grain-based bioethanol in China.

    Science.gov (United States)

    Li, Hongqiang; Wang, Limao; Shen, Lei

    2010-10-01

    Assessment of the potential CO(2) emission reduction by development of non-grain-based ethanol in China is valuable for both setting up countermeasures against climate change and formulating bioethanol policies. Based on the land occupation property, feedstock classification and selection are conducted, identifying sweet sorghum, cassava, and sweet potato as plantation feedstocks cultivated from low-quality arable marginal land resources and molasses and agricultural straws as nonplantation feedstocks derived from agricultural by-products. The feedstock utilization degree, CO(2) reduction coefficient of bioethanol, and assessment model of CO(2) emission reduction potential of bioethanol are proposed and established to assess the potential CO(2) emission reduction by development of non-grain-based bioethanol. The results show that China can obtain emission reduction potentials of 10.947 and 49.027 Mt CO(2) with non-grain-based bioethanol in 2015 and 2030, which are much higher than the present capacity, calculated as 1.95 Mt. It is found that nonplantation feedstock can produce more bioethanol so as to obtain a higher potential than plantation feedstock in both 2015 and 2030. Another finding is that developing non-grain-based bioethanol can make only a limited contribution to China's greenhouse gas emission reduction. Moreover, this study reveals that the regions with low and very low potentials for emission reduction will dominate the spatial distribution in 2015, and regions with high and very high potentials will be the majority in 2030.

  13. Perspective: Photocatalytic reduction of CO2 to solar fuels over semiconductors

    Science.gov (United States)

    Peng, Chao; Reid, Glenn; Wang, Haifeng; Hu, P.

    2017-07-01

    Increasing emissions of carbon dioxide and the depletion of finite fossil fuels have led to many concerns about global warming and energy crises. Consequently, a sustainable and alternative method, photocatalytic CO2 reduction to chemical fuels has received considerable attention. This perspective highlights recent knowledge and the main challenges in CO2 photoreduction primarily from the theoretical field. The fundamental understanding of CO2 adsorption and reaction mechanism at an atomic level is fully addressed, and the relevant effects dominating the process of CO2 photoreduction are also elucidated. Moreover, recent development of photocatalysts including structural modification is presented, which greatly affects the efficiency and selectivity of CO2 conversion. Finally, the possibilities and challenges in this field are discussed.

  14. Organic reactions for the electrochemical and photochemical production of chemical fuels from CO2--The reduction chemistry of carboxylic acids and derivatives as bent CO2 surrogates.

    Science.gov (United States)

    Luca, Oana R; Fenwick, Aidan Q

    2015-11-01

    The present review covers organic transformations involved in the reduction of CO2 to chemical fuels. In particular, we focus on reactions of CO2 with organic molecules to yield carboxylic acid derivatives as a first step in CO2 reduction reaction sequences. These biomimetic initial steps create opportunities for tandem electrochemical/chemical reductions. We draw parallels between long-standing knowledge of CO2 reactivity from organic chemistry, organocatalysis, surface science and electrocatalysis. We point out some possible non-faradaic chemical reactions that may contribute to product distributions in the production of solar fuels from CO2. These reactions may be accelerated by thermal effects such as resistive heating and illumination.

  15. Boron-doped diamond semiconductor electrodes: Efficient photoelectrochemical CO2 reduction through surface modification

    Science.gov (United States)

    Roy, Nitish; Hirano, Yuiri; Kuriyama, Haruo; Sudhagar, Pitchaimuthu; Suzuki, Norihiro; Katsumata, Ken-Ichi; Nakata, Kazuya; Kondo, Takeshi; Yuasa, Makoto; Serizawa, Izumi; Takayama, Tomoaki; Kudo, Akihiko; Fujishima, Akira; Terashima, Chiaki

    2016-11-01

    Competitive hydrogen evolution and multiple proton-coupled electron transfer reactions limit photoelectrochemical CO2 reduction in aqueous electrolyte. Here, oxygen-terminated lightly boron-doped diamond (BDDL) thin films were synthesized as a semiconductor electron source to accelerate CO2 reduction. However, BDDL alone could not stabilize the intermediates of CO2 reduction, yielding a negligible amount of reduction products. Silver nanoparticles were then deposited on BDDL because of their selective electrochemical CO2 reduction ability. Excellent selectivity (estimated CO:H2 mass ratio of 318:1) and recyclability (stable for five cycles of 3 h each) for photoelectrochemical CO2 reduction were obtained for the optimum silver nanoparticle-modified BDDL electrode at -1.1 V vs. RHE under 222-nm irradiation. The high efficiency and stability of this catalyst are ascribed to the in situ photoactivation of the BDDL surface during the photoelectrochemical reaction. The present work reveals the potential of BDDL as a high-energy electron source for use with co-catalysts in photochemical conversion.

  16. Prediction of the viscosity reduction due to dissolved CO2 of and an elementary approach in the supercritical CO2 assisted continuous particle production of a polyester resin

    NARCIS (Netherlands)

    Nalawade, Sameer P.; Nieborg, Vincent H. J.; Picchioni, Francesco; Janssen, L. P. B. M.

    2006-01-01

    The dissolution of CO2 in a polymer causes plasticization of the polymer and hence, its viscosity is reduced. A model based on the free volume theory has been used for a polyester resin, which shows a considerable reduction in the viscosity due to dissolved M. Therefore, superctitical CO2 has been u

  17. Ag-Sn Bimetallic Catalyst with a Core-Shell Structure for CO2 Reduction.

    Science.gov (United States)

    Luc, Wesley; Collins, Charles; Wang, Siwen; Xin, Hongliang; He, Kai; Kang, Yijin; Jiao, Feng

    2017-02-08

    Converting greenhouse gas carbon dioxide (CO2) to value-added chemicals is an appealing approach to tackle CO2 emission challenges. The chemical transformation of CO2 requires suitable catalysts that can lower the activation energy barrier, thus minimizing the energy penalty associated with the CO2 reduction reaction. First-row transition metals are potential candidates as catalysts for electrochemical CO2 reduction; however, their high oxygen affinity makes them easy to be oxidized, which could, in turn, strongly affect the catalytic properties of metal-based catalysts. In this work, we propose a strategy to synthesize Ag-Sn electrocatalysts with a core-shell nanostructure that contains a bimetallic core responsible for high electronic conductivity and an ultrathin partially oxidized shell for catalytic CO2 conversion. This concept was demonstrated by a series of Ag-Sn bimetallic electrocatalysts. At an optimal SnOx shell thickness of ∼1.7 nm, the catalyst exhibited a high formate Faradaic efficiency of ∼80% and a formate partial current density of ∼16 mA cm(-2) at -0.8 V vs RHE, a remarkable performance in comparison to state-of-the-art formate-selective CO2 reduction catalysts. Density-functional theory calculations showed that oxygen vacancies on the SnO (101) surface are stable at highly negative potentials and crucial for CO2 activation. In addition, the adsorption energy of CO2(-) at these oxygen-vacant sites can be used as the descriptor for catalytic performance because of its linear correlation to OCHO* and COOH*, two critical intermediates for the HCOOH and CO formation pathways, respectively. The volcano-like relationship between catalytic activity toward formate as a function of the bulk Sn concentration arises from the competing effects of favorable stabilization of OCHO* by lattice expansion and the electron conductivity loss due to the increased thickness of the SnOx layer.

  18. Zinc Imidazolate Metal-Organic Frameworks (ZIF-8) for Electrochemical Reduction of CO2 to CO.

    Science.gov (United States)

    Wang, Yulin; Hou, Pengfei; Wang, Zhuo; Kang, Peng

    2017-08-01

    Metal-organic frameworks (MOFs) are regarded as promising materials for CO2 adsorption, which is an important step in CO2 electrochemical reduction. In this work, zeolitic imidazolate framework (ZIF-8) nanomaterials were synthesized with various zinc sources and used as electrocatalysts for CO2 reduction to CO. Among them, ZIF-8, prepared using ZnSO4 , delivers the best catalytic activity towards CO2 electroreduction, with 65 % CO yield. The main catalytic center can be attributed to the discrete Zn nodes in ZIF-8. Electrolytes are important in increasing the CO selectivity, and NaCl is the best suitable electrolyte due to facile anion exchange. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. IGCC系统减排CO2的性能比较和分析%PERFORMANCE COMPARISON AND ANALYSIS OF IGCC WITH CO2 EMISSION REDUCTION

    Institute of Scientific and Technical Information of China (English)

    范江; 刘姝玮; 马素霞

    2012-01-01

    Gas producing ratio and energy consumption rate were computed respectively in the IGCC system, the IGCC system with pre-combustion CO2 capturing and that with oxy-combustion CO2 recycling. It was showed from the computed results that when coal and the gasification were in the same condition, the steam and gas turbine's work declined and the IGCC system thermal efficiency reduced by 5. 851%, which was due to the capturing of CO2 gas. When CO2 reduction rate was 86. 55% , the thermal efficiency was 42% and conducive to the operating of IGCC efficiently and cleanly. If adopting the CO2 recycling combustion technology, the system thermal efficiency was lower than that of the pre-combustion CO2 capturing system, but in which zero CO2 emission could be achieved.%分别对IGCC系统、IGCC燃烧前捕捉CO2系统以及CO2循环利用的纯氧燃烧系统的产气率和能耗进行了计算.结果表明,当煤种和气化条件不变时,燃烧前捕捉CO2会使IGCC系统的燃气轮机和蒸汽轮机做功量减少,热效率降低5.851%.当减排86.55%的CO2时,系统热效率为42%,有利于IGCC清洁高效运行.若采用CO2循环的纯氧燃烧技术,其系统热效率比未循环CO2的燃烧前捕捉系统低,但可以实现CO2的零排放.

  20. Photogeneration of Hydride Donors and Their Use Toward CO2 Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Fujita,E.; Muckerman, J.T.; Polyansky, D.E.

    2009-06-07

    Despite substantial effort, no one has succeeded in efficiently producing methanol from CO2 using homogeneous photocatalytic systems. We are pursuing reaction schemes based on a sequence of hydride-ion transfers to carry out stepwise reduction of CO2 to methanol. We are using hydride-ion transfer from photoproduced C-H bonds in metal complexes with bio-inspired ligands (i.e., NADH-like ligands) that are known to store one proton and two electrons.

  1. Ligand-based reduction of CO2 and release of CO on iron(II).

    Science.gov (United States)

    Thammavongsy, Zachary; Seda, Takele; Zakharov, Lev N; Kaminsky, Werner; Gilbertson, John D

    2012-09-01

    A synthetic cycle for the CO(2)-to-CO conversion (with subsequent release of CO) based on iron(II), a redox-active pydridinediimine ligand (PDI), and an O-atom acceptor is reported. This conversion is a passive-type ligand-based reduction, where the electrons for the CO(2) conversion are supplied by the reduced PDI ligand and the ferrous state of the iron is conserved.

  2. Biophysical controls on light response of net CO2 exchange in a winter wheat field in the North China Plain.

    Science.gov (United States)

    Tong, Xiaojuan; Li, Jun; Yu, Qiang; Lin, Zhonghui

    2014-01-01

    To investigate the impacts of biophysical factors on light response of net ecosystem exchange (NEE), CO2 flux was measured using the eddy covariance technique in a winter wheat field in the North China Plain from 2003 to 2006. A rectangular hyperbolic function was used to describe NEE light response. Maximum photosynthetic capacity (P max) was 46.6 ± 4.0 µmol CO2 m(-2) s(-1) and initial light use efficiency (α) 0.059 ± 0.006 µmol µmol(-1) in April-May, two or three times as high as those in March. Stepwise multiple linear regressions showed that P max increased with the increase in leaf area index (LAI), canopy conductance (g c) and air temperature (T a) but declined with increasing vapor pressure deficit (VPD) (P25°C or VPD>1.1-1.3 kPa, NEE residual increased with the increase in T a and VPD (Plight response parameters, simulated net CO2 uptake under the same radiation intensity averaged 18% higher in cloudy days than in sunny days during the year 2003-2006. It is necessary to include these effects in relevant carbon cycle models to improve our estimation of carbon balance at regional and global scales.

  3. CO2 的光电催化还原术%Photoelectrocatalytic Reduction of C02

    Institute of Scientific and Technical Information of China (English)

    周天辰; 何川; 张亚男; 赵国华

    2012-01-01

    CO2为温室气体的主要成分,同时也是潜在的碳能源。本文主要介绍了近年来利用光催化、电催化以及光电催化3种不同催化方法还原CO2的研究现状。文章综述了催化剂材料和催化反应体系对CO2还原效果的影响。从催化效率,光、电转化效率,选择性和能耗等不同角度进行了比较和评价。细致地讨论分析了各种催化还原方法的反应机理,并对催化还原CO2研究的发展方向和应用前景进行了展望。%Carbon dioxide (CO2) is a main component part of greenhouse gases. Since catalytic reduction of CO2 to hydrocarbon fuels can realize the recyclable utilization of carbon materials, this topic has been intensively looked into. In this article, the recent progress on the conversion of CO2 has been reviewed and discussed in detail by comparing and analyzing the catalytic efficiency and catalytic selectivity of different methods, three of which, photocatalytic reduction, electrocatalytic reduction, and photoelectrocatalytic reduction are covered. The respective catalysis mechanisms of each method, as well as the effects of different catalysts and catalytic systems on reduction of CO2 have been described. According to previous studies in this area, catalytic performance, photo-electric converting, catalytic selectivity, and energy consumption are the primary criteria on evaluating the method of reduction of CO2. On this basis, the advantages and disadvantages of catalysts and methods for reducing CO2 to useable energy are summarized and analyzed. In the last part of the article, prospects and challenges for the further development in this field are presented.

  4. Improved Accuracy of Density Functional Theory Calculations for CO2 Reduction and Metal-Air Batteries

    DEFF Research Database (Denmark)

    Christensen, Rune; Hansen, Heine Anton; Vegge, Tejs

    2015-01-01

    .e. the electrocatalytic reduction of CO2 and metal-air batteries. In theoretical studies of electrocatalytic CO2 reduction, calculated DFT-level enthalpies of reaction for CO2reduction to various products are significantly different from experimental values[1-3]. In theoretical studies of metal-air battery reactions......, systematic errors compared to experiments have also been found in calculation of enthalpies of formation for bulk metal oxide, peroxide and superoxide species[4,5]. It is here demonstrated how the errors, which depend explicitly on the choice of applied exchange-correlation functional, can be identified....... Errors can be significantly reduced by using metal chlorides as energy reference rather than pure metals. The mean absolute error per oxygen versus experiments for alkali metal peroxide and superoxide species will be 0.03 eV and 0.09 eV, respectively, using metal chlorides as reference, as compared to 0...

  5. Electrochemical reduction of CO2 to formate catalyzed by electroplated tin coating on copper foam

    Science.gov (United States)

    Wang, Yan; Zhou, Jing; Lv, Weixin; Fang, Hailin; Wang, Wei

    2016-01-01

    Sn/f-Cu electrode has been prepared by electrodeposition Sn on a Cu foam substrate in aqueous plating solution, which has been used as the cathode for electrochemical reduction of carbon dioxide (CO2) in aqueous KHCO3 solution. Here, we have explored the effects of the deposition time and the electrolysis potential on the Faradaic efficiency for producing formate. The results demonstrate that maximum Faradaic efficiency of 83.5% is obtained at -1.8 V vs. Ag/AgCl when the Sn/f-Cu electrode is prepared by electrodeposition for 35 min. The Sn/f-Cu electrode exhibits excellent catalytic activity for CO2 reduction compared with the Cu foam electrode and the Sn plate electrode. The average current density and the production rate of formate for the Sn/f-Cu electrode are more than twice those for the Sn plate electrode during electrochemical reduction of CO2.

  6. Solar Light Photocatalytic CO2 Reduction: General Considerations and Selected Bench-Mark Photocatalysts

    Directory of Open Access Journals (Sweden)

    Ștefan Neațu

    2014-03-01

    Full Text Available The reduction of carbon dioxide to useful chemicals has received a great deal of attention as an alternative to the depletion of fossil resources without altering the atmospheric CO2 balance. As the chemical reduction of CO2 is energetically uphill due to its remarkable thermodynamic stability, this process requires a significant transfer of energy. Achievements in the fields of photocatalysis during the last decade sparked increased interest in the possibility of using sunlight to reduce CO2. In this review we discuss some general features associated with the photocatalytic reduction of CO2 for the production of solar fuels, with considerations to be taken into account of the photocatalyst design, of the limitations arising from the lack of visible light response of titania, of the use of co-catalysts to overcome this shortcoming, together with several strategies that have been applied to enhance the photocatalytic efficiency of CO2 reduction. The aim is not to provide an exhaustive review of the area, but to present general aspects to be considered, and then to outline which are currently the most efficient photocatalytic systems.

  7. Solar light photocatalytic CO2 reduction: general considerations and selected bench-mark photocatalysts.

    Science.gov (United States)

    Neațu, Stefan; Maciá-Agulló, Juan Antonio; Garcia, Hermenegildo

    2014-03-25

    The reduction of carbon dioxide to useful chemicals has received a great deal of attention as an alternative to the depletion of fossil resources without altering the atmospheric CO2 balance. As the chemical reduction of CO2 is energetically uphill due to its remarkable thermodynamic stability, this process requires a significant transfer of energy. Achievements in the fields of photocatalysis during the last decade sparked increased interest in the possibility of using sunlight to reduce CO2. In this review we discuss some general features associated with the photocatalytic reduction of CO2 for the production of solar fuels, with considerations to be taken into account of the photocatalyst design, of the limitations arising from the lack of visible light response of titania, of the use of co-catalysts to overcome this shortcoming, together with several strategies that have been applied to enhance the photocatalytic efficiency of CO2 reduction. The aim is not to provide an exhaustive review of the area, but to present general aspects to be considered, and then to outline which are currently the most efficient photocatalytic systems.

  8. Fluoride-Catalyzed Methylation of Amines by Reductive Functionalization of CO2 with Hydrosilanes.

    Science.gov (United States)

    Liu, Xiao-Fang; Ma, Ran; Qiao, Chang; Cao, Han; He, Liang-Nian

    2016-11-07

    An effective and inexpensive organocatalyst tetrabutylammonium fluoride (TBAF) was developed for the reductive functionalization of CO2 with amines to selectively afford formamides or methylamines by employing hydrosilanes. Hydrosilanes with different substituents show discriminatory reducing activity. Thus, the formation of formamides and further reduction products, that is, methylamines could be controlled by elegantly tuning hydrosilane types. Formamides were obtained exclusively under an atmospheric pressure of CO2 with triethoxysilane. Using phenylsilane as a reductant, methylamines were attained with up to 99 % yield at 50 °C coupled to a complete deoxygenation of CO2 . The crucial intermediate silyl formate in the formylation step was identified and thereby a tentative mechanism involving the fluoride-promoted hydride transfer from the hydrosilane to CO2 /formamide was proposed. Striking features of this metal-free protocol are formylation and methylation of amines by reductive functionalization of CO2 with hydrosilanes and mild reaction conditions. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Photocatalytic and photoelectrocatalytic reduction of CO2 using heterogeneous catalysts with controlled nanostructures.

    Science.gov (United States)

    Xie, Shunji; Zhang, Qinghong; Liu, Guodong; Wang, Ye

    2016-01-01

    The development of efficient artificial photocatalysts and photoelectrocatalysts for the reduction of CO2 with H2O to fuels and chemicals has attracted much attention in recent years. Although the state-of-the-art for the production of fuels or chemicals from CO2 using solar energy is still far from practical consideration, rich knowledge has been accumulated to understand the key factors that determine the catalytic performances. This Feature article highlights recent advances in the photocatalytic and photoelectrocatalytic reduction of CO2 with H2O using heterogeneous semiconductor-based catalysts. The effects of structural aspects of semiconductors, such as crystalline phases, particle sizes, morphologies, exposed facets and heterojunctions, on their catalytic behaviours are discussed. The roles of different types of cocatalysts and the impact of their nanostructures on surface CO2 chemisorption and reduction are also analysed. The present article aims to provide insights into the rational design of efficient heterogeneous catalysts with controlled nanostructures for the photocatalytic and photoelectrocatalytic reduction of CO2 with H2O.

  10. Enhanced electrocatalytic CO2 reduction via field-induced reagent concentration

    Science.gov (United States)

    Liu, Min; Pang, Yuanjie; Zhang, Bo; de Luna, Phil; Voznyy, Oleksandr; Xu, Jixian; Zheng, Xueli; Dinh, Cao Thang; Fan, Fengjia; Cao, Changhong; de Arquer, F. Pelayo García; Safaei, Tina Saberi; Mepham, Adam; Klinkova, Anna; Kumacheva, Eugenia; Filleter, Tobin; Sinton, David; Kelley, Shana O.; Sargent, Edward H.

    2016-09-01

    Electrochemical reduction of carbon dioxide (CO2) to carbon monoxide (CO) is the first step in the synthesis of more complex carbon-based fuels and feedstocks using renewable electricity. Unfortunately, the reaction suffers from slow kinetics owing to the low local concentration of CO2 surrounding typical CO2 reduction reaction catalysts. Alkali metal cations are known to overcome this limitation through non-covalent interactions with adsorbed reagent species, but the effect is restricted by the solubility of relevant salts. Large applied electrode potentials can also enhance CO2 adsorption, but this comes at the cost of increased hydrogen (H2) evolution. Here we report that nanostructured electrodes produce, at low applied overpotentials, local high electric fields that concentrate electrolyte cations, which in turn leads to a high local concentration of CO2 close to the active CO2 reduction reaction surface. Simulations reveal tenfold higher electric fields associated with metallic nanometre-sized tips compared to quasi-planar electrode regions, and measurements using gold nanoneedles confirm a field-induced reagent concentration that enables the CO2 reduction reaction to proceed with a geometric current density for CO of 22 milliamperes per square centimetre at -0.35 volts (overpotential of 0.24 volts). This performance surpasses by an order of magnitude the performance of the best gold nanorods, nanoparticles and oxide-derived noble metal catalysts. Similarly designed palladium nanoneedle electrocatalysts produce formate with a Faradaic efficiency of more than 90 per cent and an unprecedented geometric current density for formate of 10 milliamperes per square centimetre at -0.2 volts, demonstrating the wider applicability of the field-induced reagent concentration concept.

  11. Enhanced electrocatalytic CO2 reduction via field-induced reagent concentration.

    Science.gov (United States)

    Liu, Min; Pang, Yuanjie; Zhang, Bo; De Luna, Phil; Voznyy, Oleksandr; Xu, Jixian; Zheng, Xueli; Dinh, Cao Thang; Fan, Fengjia; Cao, Changhong; de Arquer, F Pelayo García; Safaei, Tina Saberi; Mepham, Adam; Klinkova, Anna; Kumacheva, Eugenia; Filleter, Tobin; Sinton, David; Kelley, Shana O; Sargent, Edward H

    2016-09-15

    Electrochemical reduction of carbon dioxide (CO2) to carbon monoxide (CO) is the first step in the synthesis of more complex carbon-based fuels and feedstocks using renewable electricity. Unfortunately, the reaction suffers from slow kinetics owing to the low local concentration of CO2 surrounding typical CO2 reduction reaction catalysts. Alkali metal cations are known to overcome this limitation through non-covalent interactions with adsorbed reagent species, but the effect is restricted by the solubility of relevant salts. Large applied electrode potentials can also enhance CO2 adsorption, but this comes at the cost of increased hydrogen (H2) evolution. Here we report that nanostructured electrodes produce, at low applied overpotentials, local high electric fields that concentrate electrolyte cations, which in turn leads to a high local concentration of CO2 close to the active CO2 reduction reaction surface. Simulations reveal tenfold higher electric fields associated with metallic nanometre-sized tips compared to quasi-planar electrode regions, and measurements using gold nanoneedles confirm a field-induced reagent concentration that enables the CO2 reduction reaction to proceed with a geometric current density for CO of 22 milliamperes per square centimetre at -0.35 volts (overpotential of 0.24 volts). This performance surpasses by an order of magnitude the performance of the best gold nanorods, nanoparticles and oxide-derived noble metal catalysts. Similarly designed palladium nanoneedle electrocatalysts produce formate with a Faradaic efficiency of more than 90 per cent and an unprecedented geometric current density for formate of 10 milliamperes per square centimetre at -0.2 volts, demonstrating the wider applicability of the field-induced reagent concentration concept.

  12. Assessment of CO2 reduction potentials through clean coal technologies for future power plants in Indonesia

    Directory of Open Access Journals (Sweden)

    Monna Rozana

    2013-08-01

    Full Text Available This paper presents CO2 reduction potentials employing clean coal technologies for power plants in Indonesia. Whenlow ranked coal from huge reserves cannot be excluded from coal-fired power plants to meet electricity demand, it is criticalfor Indonesia to adopt the best available clean coal technologies for its future coal-fired power plants in order to minimizeCO2 emissions in a long term. Several types of coal-fired technologies are considered to be the best match with Indonesia’ssituation by assessing CO2 emissions from coal-fired power plants, levelized costs of electricity generation, and the cost ofCO2 avoidance. As a result, supercritical PC, IGCC, CFB, and PFBC technologies are presented as a consideration for policymaker in Indonesia.

  13. Investigation of CO2 emission reduction strategy from in-use gasoline vehicle

    Science.gov (United States)

    Choudhary, Arti; Gokhale, Sharad

    2016-04-01

    On road transport emissions is kicking off in Indian cities due to high levels of urbanization and economic growth during the last decade in Indian subcontinent. In 1951, about 17% of India's population were living in urban areas that increased to 32% in 2011. Currently, India is fourth largest Green House Gas (GHG) emitter in the world, with its transport sector being the second largest contributor of CO2 emissions. For achieving prospective carbon reduction targets, substantial opportunity among in-use vehicle is necessary to quantify. Since, urban traffic flow and operating condition has significant impact on exhaust emission (Choudhary and Gokhale, 2016). This study examined the influence of vehicular operating kinetics on CO2 emission from predominant private transportation vehicles of Indian metropolitan city, Guwahati. On-board instantaneous data were used to quantify the impact of CO2 emission on different mileage passenger cars and auto-rickshaws at different times of the day. Further study investigates CO2 emission reduction strategies by using International Vehicle Emission (IVE) model to improve co-benefit in private transportation by integrated effort such as gradual phase-out of inefficient vehicle and low carbon fuel. The analysis suggests that fuel type, vehicles maintenance and traffic flow management have potential for reduction of urban sector GHG emissions. Keywords: private transportation, CO2, instantaneous emission, IVE model Reference Choudhary, A., Gokhale, S. (2016). Urban real-world driving traffic emissions during interruption and congestion. Transportation Research Part D: Transport and Environment 43: 59-70.

  14. CO2 REDUCTION OPTIONS IN CEMENT INDUSTRY - THE NOVI POPOVAC CASE

    Directory of Open Access Journals (Sweden)

    Gordana M Stefanović

    2010-01-01

    Full Text Available The cement industry contributes about 5% to global anthropogenic CO2 emissions, and is thus an important sector in CO2-emission mitigation strategies. Carbon dioxide is emitted from the calcination process of limestone, from combustion of fuels in the kiln, and from the coal combustion during power generation. Strategies to reduce these CO2 emissions include energy efficiency improvement, new processes, shift to low carbon fuels or waste fuels in cement production, increased use of additives in cement production, alternative cements, and CO2 removal from flue gases in clinker kilns. Increased use of fly ash as an additive to cement and concrete has a number of advantages, the primary being reduction of costs of fly ash disposal, resource conservation, and cost reduction of the product. Since the production of cement requires a large amount of energy (about 2.9-3.2 GJt-1, the substitution of cement by fly ash saves not only energy but also reduces the associated greenhouse gas emissions. The paper evaluates the reduction of CO2 emissions that can be achieved by these mitigation strategies, as well as by partial substitution of cement by fly ash. The latter is important because the quality of the produced concrete depends on the physical-chemical properties of the fly ash and thus partial substitution as well as the type of fly ash (e.g., the content of CaO has an effect not only on energy consumption and emissions, but also on the produced concrete quality.

  15. Study of Electrochemical Reduction of CO2 for Future Use in Secondary Microbial Electrochemical Technologies.

    Science.gov (United States)

    Gimkiewicz, Carla; Hegner, Richard; Gutensohn, Mareike F; Koch, Christin; Harnisch, Falk

    2017-03-09

    The fluctuation and decentralization of renewable energy have triggered the search for respective energy storage and utilization. At the same time, a sustainable bioeconomy calls for the exploitation of CO2 as feedstock. Secondary microbial electrochemical technologies (METs) allow both challenges to be tackled because the electrochemical reduction of CO2 can be coupled with microbial synthesis. Because this combination creates special challenges, the electrochemical reduction of CO2 was investigated under conditions allowing microbial conversions, that is, for their future use in secondary METs. A reproducible electrodeposition procedure of In on a graphite backbone allowed a systematic study of formate production from CO2 with a high number of replicates. Coulomb efficiencies and formate production rates of up to 64.6±6.8 % and 0.013±0.002 mmolformate  h(-1)  cm(-2) , respectively, were achieved. Electrode redeposition, reusability, and long-term performance were investigated. Furthermore, the effect of components used in microbial media, that is, yeast extract, trace elements, and phosphate salts, on the electrode performance was addressed. The results demonstrate that the integration of electrochemical reduction of CO2 in secondary METs can become technologically relevant.

  16. The pH and pCO2 dependence of sulfate reduction in shallow-sea hydrothermal CO2 – venting sediments (Milos Island, Greece

    Directory of Open Access Journals (Sweden)

    Elisa eBayraktarov

    2013-05-01

    Full Text Available Microbial sulfate reduction is a dominant process of organic matter mineralization in sulfate-rich anoxic environments at neutral pH. Recent studies have demonstrated sulfate reduction in low pH environments, but investigations on the microbial activity at variable pH and CO2 partial pressure are still lacking. In this study, the effect of pH and pCO2 on microbial activity was investigated by incubation experiments with radioactive 35S targeting sulfate reduction in sediments from the shallow-sea hydrothermal vent system of Milos, Greece, where pH is naturally decreased by CO2 release. Sediments differed in their physicochemical characteristics with distance from the main site of fluid discharge. Adjacent to the vent site (T ~ 40 – 75 °C, pH ~ 5, maximal sulfate reduction rates were observed between pH 5 – 6. Sulfate reduction in hydrothermally influenced sediments decreased at neutral pH. Sediments unaffected by hydrothermal venting (T ~ 26°, pH ~ 8 expressed the highest sulfate reduction rates between pH 6 – 7. Further experiments investigating the effect of pCO2 on sulfate reduction revealed a steep decrease in activity when the partial pressure increased from 2 to 3 bar. Findings suggest that sulfate reducing microbial communities associated with hydrothermal vent system are adapted to low pH and high CO2, while communities at control sites required a higher pH for optimal activity.

  17. Photocatalytic reduction of CO2 on TiO2 and other semiconductors.

    Science.gov (United States)

    Habisreutinger, Severin N; Schmidt-Mende, Lukas; Stolarczyk, Jacek K

    2013-07-15

    Rising atmospheric levels of carbon dioxide and the depletion of fossil fuel reserves raise serious concerns about the ensuing effects on the global climate and future energy supply. Utilizing the abundant solar energy to convert CO2 into fuels such as methane or methanol could address both problems simultaneously as well as provide a convenient means of energy storage. In this Review, current approaches for the heterogeneous photocatalytic reduction of CO2 on TiO2 and other metal oxide, oxynitride, sulfide, and phosphide semiconductors are presented. Research in this field is focused primarily on the development of novel nanostructured photocatalytic materials and on the investigation of the mechanism of the process, from light absorption through charge separation and transport to CO2 reduction pathways. The measures used to quantify the efficiency of the process are also discussed in detail.

  18. Identifying Activity Descriptors for CO2 Electro-Reduction to Methanol on Rutile (110) Surfaces

    DEFF Research Database (Denmark)

    Bhowmik, Arghya; Hansen, Heine Anton; Vegge, Tejs

    2015-01-01

    Electrocatalytic reduction of CO2 to liquid fuels using energy from renewable sources has the potential to form the basis of a carbon neutral sustainable energy system, while integrating seamlessly in the established infrastructure1. Storing intermittent renewable energy in a chemical fuel...... is especially attractive to achieve high energy density required for transport applications. Among the metals, Cu electrocatalyst can convert CO2 to methane and ethylene in aqueous electrolytes at ambient temperature with moderate efficiency2. However, a high overpotential is required for this reaction...... reactivity enabling us to explore the reduction of CO2to methanol in a wide materials window. We use the computational hydrogen electrode model6 to calculate the potential dependent reaction free energies from density functional theory based calculations using BEEF-vdW functional and PAW method...

  19. Simulation of CO2 and latent heat fluxes in the North China Plain

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Yongqiang; YU; Qiang; LIU; Changming; WANG; Jing

    2005-01-01

    We constructed a coupled model for simulating plant photosynthesis and evapotranspiration (CPCEM). In the model, non-rectangular hyperbola is used to simulate leaf photosynthesis rate that is scaled up to estimate canopy gross photosynthesis rate by an integral method. Whole canopy in the model is separated into multi-layers, each of which is divided into sunlit leaves and shade leaves. Canopy net photosynthesis rate is expressed as a function of canopy conductance which is coupled with evapotranspiration. Included the coupled function,evapotranspiration is estimated with a two-layer submodel. The main features of CPCEM are: (1)easy suitability, (2) good physiological base, and (3) simple calculation procedure. Simulated results of CPCEM were compared with those by an eddy covariance system that was installed in a winter wheat farmland of the North China Plain. CPCEM gave a quite well diurnal and seasonal dynamics of net ecosystem exchange, compared with the measurements. The root mean square error between simulation and measurements was only about 2.94 μ mol m-2 s-1. Diurnal and seasonal patterns of latent heat flux with the CPCEM were similar to those of measurements.Whereas, simulated latent heat flux was evidently higher than the measured.

  20. Huge, CO2-charged debris-flow deposits and tectonic sagging in the northern plains of Mars

    Science.gov (United States)

    Tanaka, K.L.; Banerdt, W.B.; Kargel, J.S.; Hoffman, N.

    2001-01-01

    The northern plains of Mars contain a vast deposit, covering one-sixth of the planet, that apparently resulted in extensive lithospheric deformation. The center of the deposit may be as much as 2-3 km thick. The deposit has lobate margins consistent with the flow of fluidized debris for hundreds to thousands of kilometers derived from highland and high-plains sources. The deposit surface lowers inward by ???900 m in places and is locally bordered by a bulge ???300 m high. Similar deformation accompanied development of Pleistocene ice sheets on Earth. The lack of burial of a large inlier of older terrain and the response time of the mantle to the loading require that the deposit was emplaced in <1000 yr, assuming that the deposit was originally flat. We account for what may have been the largest catastrophic erosional and/or depositional event in solar system history by invoking pore-filling subsurface CO2 as an active agent in the processes of source-rock collapse and debris flow.

  1. Reductive Cleavage of CO2 by Metal-Ligand-Cooperation Mediated by an Iridium Pincer Complex.

    Science.gov (United States)

    Feller, Moran; Gellrich, Urs; Anaby, Aviel; Diskin-Posner, Yael; Milstein, David

    2016-05-25

    A unique mode of stoichiometric CO2 activation and reductive splitting based on metal-ligand-cooperation is described. The novel Ir hydride complexes [((t)Bu-PNP*)Ir(H)2] (2) ((t)Bu-PNP*, deprotonated (t)Bu-PNP ligand) and [((t)Bu-PNP)Ir(H)] (3) react with CO2 to give the dearomatized complex [((t)Bu-PNP*)Ir(CO)] (4) and water. Mechanistic studies have identified an adduct in which CO2 is bound to the ligand and metal, [((t)Bu-PNP-COO)Ir(H)2] (5), and a di-CO2 iridacycle [((t)Bu-PNP)Ir(H)(C2O4-κC,O)] (6). DFT calculations confirm the formation of 5 and 6 as reversibly formed side products, and suggest an η(1)-CO2 intermediate leading to the thermodynamic product 4. The calculations support a metal-ligand-cooperation pathway in which an internal deprotonation of the benzylic position by the η(1)-CO2 ligand leads to a carboxylate intermediate, which further reacts with the hydride ligand to give complex 4 and water.

  2. Biophysical controls on light response of net CO2 exchange in a winter wheat field in the North China Plain.

    Directory of Open Access Journals (Sweden)

    Xiaojuan Tong

    Full Text Available To investigate the impacts of biophysical factors on light response of net ecosystem exchange (NEE, CO2 flux was measured using the eddy covariance technique in a winter wheat field in the North China Plain from 2003 to 2006. A rectangular hyperbolic function was used to describe NEE light response. Maximum photosynthetic capacity (P max was 46.6 ± 4.0 µmol CO2 m(-2 s(-1 and initial light use efficiency (α 0.059 ± 0.006 µmol µmol(-1 in April-May, two or three times as high as those in March. Stepwise multiple linear regressions showed that P max increased with the increase in leaf area index (LAI, canopy conductance (g c and air temperature (T a but declined with increasing vapor pressure deficit (VPD (P25°C or VPD>1.1-1.3 kPa, NEE residual increased with the increase in T a and VPD (P<0.001, indicating that temperature and water stress occurred. When g c was more than 14 mm s(-1 in March and May and 26 mm s(-1 in April, the NEE residuals decline disappeared, or even turned into an increase in g c (P<0.01, implying shifts from stomatal limitation to non-stomatal limitation on NEE. Although the differences between sunny and cloudy sky conditions were unremarkable for light response parameters, simulated net CO2 uptake under the same radiation intensity averaged 18% higher in cloudy days than in sunny days during the year 2003-2006. It is necessary to include these effects in relevant carbon cycle models to improve our estimation of carbon balance at regional and global scales.

  3. Characteristics of pCO2 in surface water of the Bering Abyssal Plain and their effects on carbon cycle in the western Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    CHEN Liqi; GAO Zhongyong; WANG Weiqiang; YANG Xulin

    2004-01-01

    Characteristics of the pCO2 distribution in surface water of the Bering Abyssal Plain and their relationships with the ambient hydrological conditions were discussed using variations of the partial pressure of CO2 in surface water of the Bering Abyssal Plain and the Chukchi Sea. Data in this study are from a field investigation during the First Chinese National Arctic Research Expedition in 1999. Compared to the high productivity in the Bering Continental Shelf, much lower levels of chlorophyll a were observed in the Bering Abyssal Plain. The effect of hydrological factors on the pCO2 distribution in surface seawater of the Plain in summer has become a major driving force and dominated over biological factors. The Plain also presents a High Nutrient Low Chlorophyll (HNLC). In addition, the pCO2 distribution in the Bering Abyssal Plain has also been found to be influenced from the Bering Slope Current which would transform to the Anadyr Current when it inflows northwestward over the Plain. The Anadyr Current would bring a high nutrient water to the western Arctic Ocean where local nutrients are almost depleted in the surface water during the summer time. Resupplying nutrients would stimulate the growth of phytoplankton and enhance capacity of absorbing atmospheric CO2 in the surface water. Otherwise, in the Bering Sea the dissolved inorganic carbon brought from freshwater are not deposited down to the deep sea water but most of them would be transported into the western Arctic Ocean by the Alaska Coastal Current to form a carbon sink there. Therefore, the two carbon sinks in the western Arctic Ocean, one carried by the Anadyr Current and another by the Alaska Costal Current, will implicate the western Arctic Ocean in global change.

  4. Guidelines for process development and future cost reduction of CO 2 post-combustion capture

    NARCIS (Netherlands)

    Abu-Zahra, M.R.M.; Fernandez, E.S.; Goetheer, E.L.V.

    2011-01-01

    In this work, a perspective is given on the development lines for CO 2 post-combustion capture technology. Guidelines for cost reductions and suggestions for future research on solvent and process development are presented. By analyzing the post-combustion capture process in this work, it is evident

  5. Transition paths towards CO2 emission reduction in the steel industry

    NARCIS (Netherlands)

    Daniëls, Berend Wilhelm

    2002-01-01

    Radiative forcing, better known as the Greenhouse Effect, is probably the major 21st century environmental problem. Its probable cause is the anthropogenic emission of greenhouse gases, especially CO2. The Kyoto agreement enforces considerable reductions of the GHG emissions in 2010, with 6 to 8% of

  6. Effect of copper oxide electrocatalyst on CO2 reduction using Co3O4 as anode

    Directory of Open Access Journals (Sweden)

    V.S.K. Yadav

    2016-09-01

    Full Text Available The reduction of carbon dioxide (CO2 to products electrochemically (RCPE in 0.5 M NaHCO3 and Na2CO3 liquid phase electrolyte solutions was investigated. Cobalt oxide (Co3O4 as anode and cuprous oxide (Cu2O as the cathode were considered, respectively. The impacts of applied potential with time of reaction during reduction of CO2 to products were studied. The anode and cathode were prepared by depositing electrocatalysts on the graphite plate. Ultra-fast liquid chromatography (UFLC was used to analyze the products obtained from the reduction of CO2. The feasible way of reduction by applying voltages with current densities was clearly correlated. The results illustrate the capability of electrocatalyst successfully to remove atmospheric CO2 in the form of valuable chemicals. Maximum Faradaic efficiency of ethanol was 98.1% at 2 V and for formic acid (36.6% at 1.5 V was observed in NaHCO3. On the other hand, in Na2CO3 electrolyte solution maximum efficiency for ethanol was 55.21% at 1.5 V and 25.1% for formic acid at 2 V. In both electrolytes other end products like methanol, propanol, formaldehyde and acetic acid were formed at various applied voltage and output current densities.

  7. Photocatalytic CO(2) reduction using non-titanium metal oxides and sulfides.

    Science.gov (United States)

    Navalón, Sergio; Dhakshinamoorthy, Amarajothi; Alvaro, Mercedes; Garcia, Hermenegildo

    2013-04-01

    Titanium dioxide (TiO2 ) is by far the most widely used photocatalyst both for the degradation of pollutants and in the field of renewable energies for the production of solar fuels. However, TiO2 has strong limitations in CO2 reduction, particularly under visible light irradiation. The flat-band potential of electrons in the conduction band of TiO2 is lower than that required for CO2 reduction and, therefore, it seems appropriate to develop and validate materials other than TiO2 . In addition, the photoresponse of TiO2 requires photons of wavelengths in the UV range shorter than 380 nm and strategies to implement a visible-light photoresponse on TiO2 by doping have not been completely satisfactory particularly because of problems in reproducibility and stability of the materials. For these reasons, we focus in this Review on semiconductors other than TiO2 that show photocatalytic activity in CO2 reduction. Attention has been paid to the irradiation conditions to put the productivity data into context. The role of co-catalyst and heterojunctions to increase the efficiency of charge separation is also discussed. Our aim is to describe the state of the art in the field of photocatalytic CO2 reduction using materials other than TiO2 , trying to trigger further research in this area.

  8. Permeability reduction produced by grain reorganization and accumulation of exsolved CO2 during geologic carbon sequestration: a new CO2 trapping mechanism.

    Science.gov (United States)

    Luhmann, Andrew J; Kong, Xiang-Zhao; Tutolo, Benjamin M; Ding, Kang; Saar, Martin O; Seyfried, William E

    2013-01-01

    Carbon sequestration experiments were conducted on uncemented sediment and lithified rock from the Eau Claire Formation, which consisted primarily of K-feldspar and quartz. Cores were heated to accentuate reactivity between fluid and mineral grains and to force CO(2) exsolution. Measured permeability of one sediment core ultimately reduced by 4 orders of magnitude as it was incrementally heated from 21 to 150 °C. Water-rock interaction produced some alteration, yielding sub-μm clay precipitation on K-feldspar grains in the core's upstream end. Experimental results also revealed abundant newly formed pore space in regions of the core, and in some cases pores that were several times larger than the average grain size of the sediment. These large pores likely formed from elevated localized pressure caused by rapid CO(2) exsolution within the core and/or an accumulating CO(2) phase capable of pushing out surrounding sediment. CO(2) filled the pores and blocked flow pathways. Comparison with a similar experiment using a solid arkose core indicates that CO(2) accumulation and grain reorganization mainly contributed to permeability reduction during the heated sediment core experiment. This suggests that CO(2) injection into sediments may store more CO(2) and cause additional permeability reduction than is possible in lithified rock due to grain reorganization.

  9. Analyzing and forecasting CO2 emission reduction in China's steel industry

    Science.gov (United States)

    Gao, Chengkang; Wang, Dan; Zhao, Baohua; Chen, Shan; Qin, Wei

    2015-03-01

    Recent measures of carbon dioxide emissions from the steel industry of China have indicated a high rate of total CO2 emissions from the industry, even compared to the rest of the world. So, CO2 emission reduction in China's steel industry was analyzed, coupling the whole process and scenarios analysis. First, assuming that all available advanced technologies are almost adopted, this study puts forward some key potential-sectors and explores an optimal technical route for reducing CO2 emissions from the Chinese steel industry based on whole process analysis. The results show that in the stages of coking, sintering, and iron making, greater potential for reducing emissions would be fulfilled by taking some technological measures. If only would above well-developed technologies be fulfill, the CO2 emissions from 5 industry production stages would be reduced substantially, and CO2 emissions per ton of steel could be decreased to 1.24 (ton/ton-steel) by 2020. At the same time, the scenarios analysis indicates that if mature carbon-reducing technologies are adopted, and if the difference between steel output growth rate and the GDP growth rate could be controlled below 3%, CO2 emissions from China's steel industry would approach the goal of reducing CO2 emissions per GDP unit by 40%-45% of the 2005 level by 2020. This indicates that the focus of carbon dioxide emissions reduction in China lies in policy adjustments in order to enhance technological application, and lies in reasonably controlling the pace of growth of GDP and steel output.

  10. Assessment of Alternative Scenarios for CO2 Reduction Potential in the Residential Building Sector

    Directory of Open Access Journals (Sweden)

    Young-Sun Jeong

    2017-03-01

    Full Text Available The South Korean government announced its goals of reducing the country’s CO2 emissions by up to 30% below the business as usual (BAU projections by 2020 in 2009 and 37% below BAU projections by 2030 in 2015. This paper explores the potential energy savings and reduction in CO2 emissions offered by residential building energy efficiency policies and plans in South Korea. The current and future energy consumption and CO2 emissions in the residential building were estimated using an energy–environment model from 2010 to 2030. The business as usual scenario is based on the energy consumption characteristic of residential buildings using the trends related to socio-economic prospects and the number of dwellings. The alternative scenarios took into account energy efficiency for new residential buildings (scenario I, refurbishment of existing residential buildings (scenario II, use of highly efficient boilers (scenario III, and use of a solar thermal energy system (scenario IV. The results show that energy consumption in the residential building sector will increase by 33% between 2007 and 2030 in the BAU scenario. Maximum reduction in CO2 emissions in the residential building sector of South Korea was observed by 2030 in scenario I. In each alternative scenario analysis, CO2 emissions were 12.9% lower than in the business as usual scenario by the year 2030.

  11. Sharing global CO2 emission reductions among one billion high emitters.

    Science.gov (United States)

    Chakravarty, Shoibal; Chikkatur, Ananth; de Coninck, Heleen; Pacala, Stephen; Socolow, Robert; Tavoni, Massimo

    2009-07-21

    We present a framework for allocating a global carbon reduction target among nations, in which the concept of "common but differentiated responsibilities" refers to the emissions of individuals instead of nations. We use the income distribution of a country to estimate how its fossil fuel CO(2) emissions are distributed among its citizens, from which we build up a global CO(2) distribution. We then propose a simple rule to derive a universal cap on global individual emissions and find corresponding limits on national aggregate emissions from this cap. All of the world's high CO(2)-emitting individuals are treated the same, regardless of where they live. Any future global emission goal (target and time frame) can be converted into national reduction targets, which are determined by "Business as Usual" projections of national carbon emissions and in-country income distributions. For example, reducing projected global emissions in 2030 by 13 GtCO(2) would require the engagement of 1.13 billion high emitters, roughly equally distributed in 4 regions: the U.S., the OECD minus the U.S., China, and the non-OECD minus China. We also modify our methodology to place a floor on emissions of the world's lowest CO(2) emitters and demonstrate that climate mitigation and alleviation of extreme poverty are largely decoupled.

  12. Electrochemical CO2 and CO reduction on metal-functionalized porphyrin-like graphene

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Vanin, Marco; Karamad, Mohammedreza

    2013-01-01

    Porphyrin-like metal-functionalized graphene structures have been investigated as possible catalysts for CO2 and CO reduction to methane or methanol. The late transition metals (Cu, Ag, Au, Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, Os) and some p (B, Al, Ga) and s (Mg) metals comprised the center...... instead of CO2. Volcano plots were constructed on the basis of scaling relations of reaction intermediates, and from these plots the reaction steps with the highest overpotentials were deduced. The Rh-porphyrin-like functionalized graphene was identified as the most active catalyst for producing methanol...

  13. Identifying Activity Descriptors for CO2 Electro-Reduction to Methanol on Rutile (110) Surfaces

    DEFF Research Database (Denmark)

    Bhowmik, Arghya; Hansen, Heine Anton; Vegge, Tejs

    2015-01-01

    towards electrocatalytic production of methanol. We would like to acknowledge the Lundbeck Foundation for financial support of this work. References: 1. Lewis, N. S. & Nocera, D. G. Powering the planet: chemical challenges in solar energy utilization. Proc. Natl. Acad. Sci. U. S. A.103,15729–35 (2006...... and almost no alcohols are produced. Experimental studies have shown that mixed rutile oxides (Ru/Ir/Ti) can catalyze the conversion of CO2 to alcohols3-5. However, very little is known about the reduction of CO2to alcohols on oxide electrocatalysts. Here, we present a computational study of the thermo...

  14. Importance of the hydrogen route in up-scaling electrosynthesis for microbial CO2 reduction

    OpenAIRE

    Blanchet, Elise; Duquenne, François; Rafrafi, Yan; Etcheverry, Luc; Erable, Benjamin; Bergel, Alain

    2015-01-01

    International audience; Microbial electrochemical reduction of CO2 was carried out under two different applied potentials, −0.36 V and −0.66 V vs. SHE, using a biological sludge as the inoculum. Both potentials were thermodynamically appropriate for converting CO2 to acetate but only −0.66 V enabled hydrogen evolution. No acetate production was observed at −0.36 V, while up to 244 ± 20 mg L−1 acetate was produced at −0.66 V vs. SHE. The same microbial inoculum implemented in gas–liquid contac...

  15. Low Overpotential and High Current CO2 Reduction with Surface Reconstructed Cu Foam Electrodess

    KAUST Repository

    Min, Shixiong

    2016-06-23

    While recent reports have demonstrated that oxide-derived Cu-based electrodes exhibit high selectivity for CO2 reduction at low overpotential, the low catalytic current density (<2 mA/cm2 at -0.45 V vs. RHE) still largely limits its applications for large-scale fuel synthesis. Here we report an extremely high current density for CO2 reduction at low overpotential using a Cu foam electrode prepared by air-oxidation and subsequent electroreduction. Apart from possessing three-dimensional (3D) open frameworks, the resulting Cu foam electrodes prepared at higher temperatures exhibit enhanced electrochemically active surface area and distinct surface structures. In particular, the Cu foam electrode prepared at 500 °C exhibits an extremely high geometric current density of ~9.4 mA/cm2 in CO2-satrurated 0.1 M KHCO3 aqueous solution and achieving ~39% CO and ~23% HCOOH Faradaic efficiencies at -0.45 V vs. RHE. The high activity and significant selectivity enhancement are attributable to the formation of abundant grain-boundary supported active sites and preferable (100) and (111) facets as a result of reconstruction of Cu surface facets. This work demonstrates that the structural integration of Cu foam with open 3D frameworks and the favorable surface structures is a promising strategy to develop an advanced Cu electrocatalyst that can operate at high current density and low overpotential for CO2 reduction.

  16. Exploring the intermediates of photochemical CO2 reduction: reaction of Re(dmb)(CO)3 COOH with CO2.

    Science.gov (United States)

    Agarwal, Jay; Sanders, Brian C; Fujita, Etsuko; Schaefer, Henry F; Harrop, Todd C; Muckerman, James T

    2012-07-11

    We have investigated the reaction of Re(dmb)(CO)(3)COOH with CO(2) using density functional theory, and propose a mechanism for the production of CO. This mechanism supports the role of Re(dmb)(CO)(3)COOH as a key intermediate in the formation of CO. Our new experimental work supports the proposed scheme.

  17. Research Progresses on Photocatalytic Reduction of CO2%光催化还原CO2的研究进展

    Institute of Scientific and Technical Information of China (English)

    赵毅; 李晓蕾; 马双忱

    2011-01-01

    介绍了多种将CO2转化为化工产品的光催化还原体系,包括TiO2体系、金属修饰的TiO2体系、有机光敏化剂修饰的TiO2体系和其他光敏半导体材料体系.评述了不同光催化体系的特点及其催化性能.讨论了光源波长、反应温度、CO2压力和浓度、H2O和CO2摩尔比等实验条件对反应产物种类及其产量的影响,指出催化剂的活性、光源波长和CO2压力是CO2转化的关键因素.%Photocatalytic reduction systems for transformation of CO2 to chemical products are introduced, involving TiO2 system, metal-modified TiO2 system, organic photosensitive agent-modified TiO2 system and other photosensitive semiconductor material systems. The characteristics and photocatalytic capabilities of these photocatalytic systems are commented. The effects of the experimental conditions on the reaction products and their yields, such as light source wavelength, reaction temperature, CO2pressure and concentration, and mole ratio of H2O to CO2, are discussed. It is pointed out that the wavelength of light source and the pressure of CO2 are the dominant factors for the transformation of CO2.

  18. Role of Southern Ocean stratification in glacial atmospheric CO2 reduction

    Science.gov (United States)

    Kobayashi, H.; Oka, A.

    2014-12-01

    reduction in atmospheric CO2 concentration than previous studies. However, we still fail to explain the full amplitude of recorded glacial reduction of atmospheric CO2 concentration. The carbonate compensation process, which is not incorporated in our simulations, might be required for further reduction in atmospheric CO2 concentration.

  19. Improvement of photosynthetic CO2 fixation at high light intensity through reduction of chlorophyll antenna size.

    Science.gov (United States)

    Lee, James W; Mets, Laurens; Greenbau, Elias

    2002-01-01

    At elevated light intensities (greater than approximately 200 microE/[m2 x s]), the kinetic imbalance between the rate of photon excitation and thermally activated electron transport results in saturation of the rate of photosynthesis. Since maximum terrestrial solar radiation can reach 200 microE/(m2 x s), a significant opportunity exists to improve photosynthetic efficiency at elevated light intensities by achieving a kinetic balance between photon excitation and electron transport, especially in designed large-scale photosynthetic reactors in which a low-cost and efficient biomass production system is desired. One such strategy is a reduction in chlorophyll (chl) antenna size in relation to the reaction center that it serves. In this article, we report recent progress in this area of research. Light-saturation studies for CO2 fixation were performed on an antenna-deficient mutant of Chlamydomonas (DS521) and the wild type (DES15) with 700 ppm of CO2 in air. The light-saturated rate for CO2 assimilation in the mutant DS521 was about two times higher (187 micromol/[h x mg of chl]) than that of the wild type, DES15 (95 micromol/[h x mg of chl]). Significantly, a partial linearization of the light-saturation curve was also observed. These results confirmed that DS521 has a smaller relative chl antenna size and demonstrated that reduction of relative antenna size can improve the overall efficiency of photon utilization at higher light intensities. The antenna-deficient mutant DS521 can provide significant resistance to photoinhibition, in addition to improvement in the overall efficiency of CO2 fixation at high light. The experimental data reported herein support the idea that reduction in chl antenna size could have significant implications for both fundamental understanding of photosynthesis and potential application to improve photosynthetic CO2 fixation efficiency.

  20. Analysis of GHG Emission Reduction in South Korea Using a CO2 Transportation Network Optimization Model

    Directory of Open Access Journals (Sweden)

    Suk Ho Jin

    2017-07-01

    Full Text Available Korea’s national carbon capture and storage (CCS master plan aims to commercialize CCS projects by 2030. Furthermore, the Korean government is forced to reduce emissions from various sectors, including industries and power generation, by 219 million tons by 2030. This study analyzes a few scenarios of Korean CCS projects with a CO2 pipeline transportation network optimization model for minimizing the total facility cost and pipeline cost. Our scenarios are based on the “2030 asic roadmap for reducing greenhouse gases” established by the government. The results for each scenario demonstrate that the effective design and implementation of CO2 pipeline network enables the lowering of CO2 units cost. These suggest that CO2 transportation networks, which connect the capture and sequestration parts, will be more important in the future and can be used to substitute and supplement the emission reduction target in case the execution of other reduction options faces uncertainty. Our mathematical model and scenario designs will be helpful for various countries which plan to introduce CCS technology.

  1. The postural reduction in middle cerebral artery blood velocity is not explained by PaCO2

    DEFF Research Database (Denmark)

    Immink, R V; Secher, N H; Roos, C M

    2006-01-01

    Vmean and the end-tidal carbon-dioxide tension (PETCO2) decrease, suggesting that PaCO2 contributes to the reduction in MCA Vmean. In a fixed body position, PETCO2 tracks changes in the PaCO2 but when assuming the upright position, cardiac output (Q) decreases and its distribution over the lung changes......, while ventilation (VE) increases suggesting that PETCO2 decreases more than PaCO2. This study evaluated whether the postural reduction in PaCO2 accounts for the postural decline in MCA Vmean). From the supine to the upright position, VE, Q, PETCO2, PaCO2, MCA Vmean, and the near...

  2. Reduction of CO2 to CO Using CO2-H2 Non-equilibrium Plasma Method%利用非平衡等离子体方法将CO2还原成CO的研究

    Institute of Scientific and Technical Information of China (English)

    周军成; 尹燕华; 郑邯勇; 徐月; 周旭; 龚俊松

    2012-01-01

    CO2和H2合成CO是CO2化学利用的重要过程,然而,传统的催化转化难以实现高效转化。在室温和大气压下,通过非平衡等离子体对H2和CO2的活化作用,考察了等离子体反应器结构、极间距、放电功率和氢碳比等对CO2转化率、CO选择性和CO2转化的能量效率影响。实验结果表明,在室温和大气压下,用等离子体法可将CO2高效的还原为CO,适当调节上述各参数可提高CO2的转化率。采用管管式等离子体反应器,在放电频率为10kHz、H2与CO2体积进料比为2:1、放电功率为80W、CO2气体体积流量为120mL/min的条件下,CO2转化率为88.2%,CO选择性为100%。%Conversion of CO2 to CO by H2 has been recognized as one of the important processes for CO2 utilization, but it is difficult to obtain high CO yield by catalytic method. We discussed the role of plasma activation in the direct gas phase reduction of CO2 to CO. The plasma was obtained by dielectric barrier discharge to the mixture of H2 and CO2 at room temperature and atmospheric pressure. Moreover, we investigated the effects of main parameters on CO2 conversion, CO selectivity and energy efficiency of CO2 conversion , such as discharge power,the structure of plasma reactors, the ratio of H2 to CO2 as well as space between electrodes. It is observed that, at room temperature and atmospheric pressure, H2 and CO2 can be directly converted into CO only by plasma activation. The proper adjustment of above parameters can increase CO2 conversion. When the CO2 flow rate of the feed gas, the ratio of H2 to CO2, the discharge power, and the discharge frequency are fixed at 120 mL/min, 80 W and 10 kHz, respectively, the CO2 conversion efficiency and CO selectivity are 88.2% and 100%, respectively.

  3. Assessing the Potential of Utilization and Storage Strategies for Post-Combustion CO2 Emissions Reduction

    OpenAIRE

    Styring, P.; Armstrong, K.

    2015-01-01

    The emissions reduction potential of three carbon dioxide handling strategies for post-combustion capture is considered. These are carbon capture and sequestration/storage (CCS), enhanced hydrocarbon recovery (EHR), and carbon dioxide utilization (CDU) to produce synthetic oil. This is performed using common and comparable boundary conditions including net CO2 sequestered based on equivalent boundary conditions. This is achieved using a “cradle to grave approach” where the final destination a...

  4. Electrochemical promotion of catalysis over Pd nanoparticles for CO2 reduction.

    Science.gov (United States)

    Cai, Fan; Gao, Dunfeng; Zhou, Hu; Wang, Guoxiong; He, Ting; Gong, Huimin; Miao, Shu; Yang, Fan; Wang, Jianguo; Bao, Xinhe

    2017-04-01

    Electrochemical promotion of catalysis (EPOC) has been shown to accelerate the rate of many heterogeneous catalytic reactions; however, it has rarely been reported in low-temperature aqueous electrochemical reactions. Herein, we report a significant EPOC effect for the CO2 reduction to generate formate over Pd nanoparticles (NPs) in a 1 M KHCO3 aqueous solution. By applying a negative potential over differently-sized Pd NPs, the rate of formate production is greatly improved as compared to that at an open-circuit voltage, with a rate enhancement ratio ranging from 10 to 143. The thermocatalytic and electrocatalytic reduction of CO2 compete with each other and are promoted by the applied negative potential and H2 in the feeds, respectively. Inspired by the EPOC effect, a composite electrode containing Pd/C and Pt/C catalysts on different sides of a carbon paper was constructed for catalyzing the CO2 reduction without adding H2 to the feeds. Water electrolysis over Pt NPs generates H2, which then effectively promotes formate production over Pd NPs.

  5. Membraneless laminar flow cell for electrocatalytic CO2 reduction with liquid product separation

    Science.gov (United States)

    Monroe, Morgan M.; Lobaccaro, Peter; Lum, Yanwei; Ager, Joel W.

    2017-04-01

    The production of liquid fuel products via electrochemical reduction of CO2 is a potential path to produce sustainable fuels. However, to be practical, a separation strategy is required to isolate the fuel-containing electrolyte produced at the cathode from the anode and also prevent the oxidation products (i.e. O2) from reaching the cathode. Ion-conducting membranes have been applied in CO2 reduction reactors to achieve this separation, but they represent an efficiency loss and can be permeable to some product species. An alternative membraneless approach is developed here to maintain product separation through the use of a laminar flow cell. Computational modelling shows that near-unity separation efficiencies are possible at current densities achievable now with metal cathodes via optimization of the spacing between the electrodes and the electrolyte flow rate. Laminar flow reactor prototypes were fabricated with a range of channel widths by 3D printing. CO2 reduction to formic acid on Sn electrodes was used as the liquid product forming reaction, and the separation efficiency for the dissolved product was evaluated with high performance liquid chromatography. Trends in product separation efficiency with channel width and flow rate were in qualitative agreement with the model, but the separation efficiency was lower, with a maximum value of 90% achieved.

  6. Storage of Renewable Energy by Reduction of CO2 with Hydrogen.

    Science.gov (United States)

    Züttel, Andreas; Mauron, Philippe; Kato, Shunsuke; Callini, Elsa; Holzer, Marco; Huang, Jianmei

    2015-01-01

    The main difference between the past energy economy during the industrialization period which was mainly based on mining of fossil fuels, e.g. coal, oil and methane and the future energy economy based on renewable energy is the requirement for storage of the energy fluxes. Renewable energy, except biomass, appears in time- and location-dependent energy fluxes as heat or electricity upon conversion. Storage and transport of energy requires a high energy density and has to be realized in a closed materials cycle. The hydrogen cycle, i.e. production of hydrogen from water by renewable energy, storage and use of hydrogen in fuel cells, combustion engines or turbines, is a closed cycle. However, the hydrogen density in a storage system is limited to 20 mass% and 150 kg/m(3) which limits the energy density to about half of the energy density in fossil fuels. Introducing CO(2) into the cycle and storing hydrogen by the reduction of CO(2) to hydrocarbons allows renewable energy to be converted into synthetic fuels with the same energy density as fossil fuels. The resulting cycle is a closed cycle (CO(2) neutral) if CO(2) is extracted from the atmosphere. Today's technology allows CO(2) to be reduced either by the Sabatier reaction to methane, by the reversed water gas shift reaction to CO and further reduction of CO by the Fischer-Tropsch synthesis (FTS) to hydrocarbons or over methanol to gasoline. The overall process can only be realized on a very large scale, because the large number of by-products of FTS requires the use of a refinery. Therefore, a well-controlled reaction to a specific product is required for the efficient conversion of renewable energy (electricity) into an easy to store liquid hydrocarbon (fuel). In order to realize a closed hydrocarbon cycle the two major challenges are to extract CO(2) from the atmosphere close to the thermodynamic limit and to reduce CO(2) with hydrogen in a controlled reaction to a specific hydrocarbon. Nanomaterials with

  7. Alternative photocatalysts to TiO2 for the photocatalytic reduction of CO2

    Science.gov (United States)

    Nikokavoura, Aspasia; Trapalis, Christos

    2017-01-01

    The increased concentration of CO2 in the atmosphere, originating from the burning of fossil fuels in stationary and mobile sources, is referred as the "Anthropogenic Greenhouse Effect" and constitutes a major environmental concern. The scientific community is highly concerned about the resulting enhancement of the mean atmospheric temperature, so a vast diversity of methods has been applied. Thermochemical, electrochemical, photocatalytic, photoelectrochemical processes, as well as combination of solar electricity generation and water splitting processes have been performed in order to lower the CO2 atmospheric levels. Photocatalytic methods are environmental friendly and succeed in reducing the atmospheric CO2 concentration and producing fuels or/and useful organic compounds at the same time. The most common photocatalysts for the CO2 reduction are the inorganic, the carbon based semiconductors and the hybrids based on semiconductors, which combine stability, low cost and appropriate structure in order to accomplish redox reactions. In this review, inorganic semiconductors such as single-metal oxide, mixed-metal oxides, metal oxide composites, layered double hydroxides (LDHs), salt composites, carbon based semiconductors such as graphene based composites, CNT composites, g-C3N4 composites and hybrid organic-inorganic materials (ZIFs) were studied. TiO2 and Ti based photocatalysts are extensively studied and therefore in this review they are not mentioned.

  8. Molybdenum carbide as alternative catalysts to precious metals for highly selective reduction of CO2 to CO.

    Science.gov (United States)

    Porosoff, Marc D; Yang, Xiaofang; Boscoboinik, J Anibal; Chen, Jingguang G

    2014-06-23

    Rising atmospheric CO2 is expected to have negative effects on the global environment from its role in climate change and ocean acidification. Utilizing CO2 as a feedstock to make valuable chemicals is potentially more desirable than sequestration. A substantial reduction of CO2 levels requires a large-scale CO2 catalytic conversion process, which in turn requires the discovery of low-cost catalysts. Results from the current study demonstrate the feasibility of using the non-precious metal material molybdenum carbide (Mo2C) as an active and selective catalyst for CO2 conversion by H2.

  9. Investigation of the charge-transfer in photo-excited nanoparticles for CO2 reduction in non-aqueous media

    Directory of Open Access Journals (Sweden)

    Dimitrijević Nada M.

    2013-01-01

    Full Text Available Photoinduced charge separation in TiO2 and Cu2O semiconductor nanoparticles was examined using Electron Paramagnetic Resonance spectroscopy in order to get insight into the photocatalytic reduction of CO2 in nonaqueous media. For dissolution/grafting of CO2 we have used carboxy-PEG4-amine, and as a solvent poly(ethylene glycol 200. We have found that, in this system, reduction of CO2 starts at potential of -0.5 V vs Ag/AgCl, which is significantly more positive than the potential for electrochemical reduction of CO2 in most organic solvents and water (-2.0 V vs. Ag/AgCl. The electron transfer from excited nanoparticles to CO2 is governed both by thermodynamic and kinetic parameters, namely by the redox potential of conduction band electrons and adsorption/binding of CO2 on the surface of nanoparticles.

  10. Cement replacement by sugar cane bagasse ash: CO2 emissions reduction and potential for carbon credits.

    Science.gov (United States)

    Fairbairn, Eduardo M R; Americano, Branca B; Cordeiro, Guilherme C; Paula, Thiago P; Toledo Filho, Romildo D; Silvoso, Marcos M

    2010-09-01

    This paper presents a study of cement replacement by sugar cane bagasse ash (SCBA) in industrial scale aiming to reduce the CO(2) emissions into the atmosphere. SCBA is a by-product of the sugar/ethanol agro-industry abundantly available in some regions of the world and has cementitious properties indicating that it can be used together with cement. Recent comprehensive research developed at the Federal University of Rio de Janeiro/Brazil has demonstrated that SCBA maintains, or even improves, the mechanical and durability properties of cement-based materials such as mortars and concretes. Brazil is the world's largest sugar cane producer and being a developing country can claim carbon credits. A simulation was carried out to estimate the potential of CO(2) emission reductions and the viability to issue certified emission reduction (CER) credits. The simulation was developed within the framework of the methodology established by the United Nations Framework Convention on Climate Change (UNFCCC) for the Clean Development Mechanism (CDM). The State of São Paulo (Brazil) was chosen for this case study because it concentrates about 60% of the national sugar cane and ash production together with an important concentration of cement factories. Since one of the key variables to estimate the CO(2) emissions is the average distance between sugar cane/ethanol factories and the cement plants, a genetic algorithm was developed to solve this optimization problem. The results indicated that SCBA blended cement reduces CO(2) emissions, which qualifies this product for CDM projects. 2010 Elsevier Ltd. All rights reserved.

  11. The Analysis of CO2 Emissions and Reduction Potential in China’s Transport Sector

    Directory of Open Access Journals (Sweden)

    Wei Li

    2016-01-01

    Full Text Available China’s transport sector is responsible for approximately 10% of national CO2 emissions. In the process of industrialization and urbanization of China, emissions from transport sector would continuously increase. In order to investigate the emissions and reduction potential and provide the policy guidance for policymakers in China’s transport sector, this study decomposed the CO2 emissions using the Kaya identity, calculated the contribution based on the Logarithmic Mean Divisia Index (LMDI method to explore the underlying determinants of emissions change, and then constructed different scenarios to predict the emissions and estimate the potential of emission reduction in the future. Results indicated that carbon emissions in China’s transport sector have increased from 123.14 Mt in 1995 to 670.76 Mt in 2012. Income effect is the dominant factor that results in the increase of emissions while energy intensity effect is the main driving force to lower carbon emissions. The transportation modal shifting, transportation intensity change, and population growth have the positive but relatively minor impact on emissions. The accumulated emission reduction is expected to be 1825.97 Mt, which is 3 times more than the emissions in 2010. Policy recommendations are thus put forward for future emission reduction.

  12. Examining ruthenium chromophores for the photochemical reduction of CO2 to methanol

    Science.gov (United States)

    Boston, David J.

    Our consumption of energy for transportation and electricity has been growing as quickly as our population. As this demand for energy increases we increase our production of carbon dioxide by the burning of fossil fuels to try and meet this increasing demand. A sustainable method to convert carbon dioxide (CO2) to a viable liquid fuel is one potential way in which both the increasing energy demand and increasing CO2 concentration issues can both be helped. Currently such methods being investigated include thermal, electrochemical, and photochemical processes. Because thermal conversion is not an ideal situation because of the requirement of strong reducing agents or extreme conditions such as steam reformation reactions, we need to find better alternatives such as electrochemical and photochemical methods. Both electrochemical and photochemical methods have the ability to be sustainable, however, the vast majority of these systems are limited to producing CO and/or formic acid, with only a few performing deeper reduction to products such formaldehyde, methanol and methane. All of the systems capable of reducing CO2 past two electrons involve either a heterogeneous catalyst (e.g. TiO2) or an electrode. In recent times Bocarsly and coworkers have shown that pyridine was capable of reducing CO2 to methanol through a sequential process of proton and electron transfers. This process seems to start with the formation of a CO2-pyridine adduct in solution that is reduced one more time to form formate/formic acid. The next reduction is a slow process and allows for a buildup of formate in solution leading to a higher formate concentration in solution. The subsequent reductions seem to occur very rapidly and form methanol at good efficiencies. Theoretical work done recently has argued for the necessity of the Pt, Pd, or GaP surface in the electrochemistry. Carter and coworkers have claimed that the surface of the electrode is a necessary part of the catalysis with the

  13. Dual-phase spinel MnCo2O4 and spinel MnCo2O4/nanocarbon hybrids for electrocatalytic oxygen reduction and evolution.

    Science.gov (United States)

    Ge, Xiaoming; Liu, Yayuan; Goh, F W Thomas; Hor, T S Andy; Zong, Yun; Xiao, Peng; Zhang, Zheng; Lim, Suo Hon; Li, Bing; Wang, Xin; Liu, Zhaolin

    2014-08-13

    Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are essential reactions for energy-storage and -conversion devices relying on oxygen electrochemistry. High-performance, nonprecious metal-based hybrid catalysts are developed from postsynthesis integration of dual-phase spinel MnCo2O4 (dp-MnCo2O4) nanocrystals with nanocarbon materials, e.g., carbon nanotube (CNT) and nitrogen-doped reduced graphene oxide (N-rGO). The synergic covalent coupling between dp-MnCo2O4 and nanocarbons effectively enhances both the bifunctional ORR and OER activities of the spinel/nanocarbon hybrid catalysts. The dp-MnCo2O4/N-rGO hybrid catalysts exhibited comparable ORR activity and superior OER activity compared to commercial 30 wt % platinum supported on carbon black (Pt/C). An electrically rechargeable zinc-air battery using dp-MnCo2O4/CNT hybrid catalysts on the cathode was successfully operated for 64 discharge-charge cycles (or 768 h equivalent), significantly outperforming the Pt/C counterpart, which could only survive up to 108 h under similar conditions.

  14. The Emission Reduction Potential of Non-CO2 Greenhouse Gases in China and Its Policy Implications

    Institute of Scientific and Technical Information of China (English)

    Delin; HUANG; Songfeng; CAI; Zhen; WANG

    2013-01-01

    Using the improved Energy-Environmental Version of the GTAP Model (GTAP-E) and the sixth version of emission database of non-CO2 greenhouse gases, we simulate the emission reduction potential of non-CO2 greenhouse gases in China and its policy implications. The results show that at present, China is a country with the greatest emission of non-CO2 greenhouse gases in the world, and the emission will account for about 20% of the world’s total emission in 2020. The proportion of emission of non-CO2 greenhouse gases from the agricultural sector reaches 73%. In the next 10 years, the emission of non-CO2 gases from cattle and sheep, industry and service industry will experience the highest growth rate; the growth rate of emission from service industry will be higher than that of emission from industry, and the emission from service industry will exceed that from industry after 2010. China can implement emission reduction policy of non-CO2 greenhouse gases to ease the international pressure of CO2 emission reduction. Although the high carbon tax collected can reduce considerable non-CO2 emission, there is little difference in policy efficiency between high carbon tax and low carbon tax. So, in the implementation of emission reduction carbon tax policy of non-CO2 gases, it is necessary to control the carbon tax at a low level.

  15. Surface-reconstructed Cu Electrode via a Facile Electrochemical Anodization-Reduction Process for Low Overpotential CO 2 reduction

    KAUST Repository

    Min, Shixiong

    2017-03-21

    A high-surface-area Cu electrode, fabricated by a simple electrochemical anodization-reduction method, exhibits high activity and selectivity for CO2 reduction at low overpotential in 0.1 M KHCO3 solution. A faradaic efficiency of 37% for HCOOH and 27% for CO production was achieved with the current density of 1.5 mA cm-2 at −0.64 V vs. RHE, much higher than that of polycrystalline Cu. The enhanced catalytic performance is a result of the formation of the high electrochemical active surface area and high density of preferred low-index facets.

  16. Assessing the potential of utilisation and storage strategies for post-combustion CO2 emissions reduction

    Directory of Open Access Journals (Sweden)

    Peter eStyring

    2015-03-01

    Full Text Available The emissions reduction potential of three carbon dioxide handling strategies for post-combustion capture are considered. These are carbon capture and sequestration/storage (CCS, enhanced hydrocarbon recovery (EHR and carbon dioxide utilization (CDU to produce synthetic oil. This is performed using common and comparable boundary conditions including net CO2 sequestered based on equivalent boundary conditions. This is achieved using a 'cradle to grave approach' where the final destination and fate of any product is considered. The input boundary is pure CO2 that has been produced using a post-combustion capture process as this is common between all processes. The output boundary is the emissions resulting from any product produced with the assumption that the majority of the oil will go to combustion processes. We also consider the 'cradle to gate' approach where the ultimate fate of the oil is not considered as this is a boundary condition often applied to EHR processes. Results show that while CCS can make an impact on CO2 emissions, CDU will have a comparable effect whilst generating income while EHR will ultimately increase net emissions. The global capacity for CDU is also compared against CCS using data based on current and planned CCS projects. Analysis shows that current CDU represent a greater volume of capture than CCS processes and that this gap is likely to remain well beyond 2020 which is the limit of the CCS projects in the database.

  17. Reduction of CO2 by nickel (II) macrocycle catalyst at HMDE

    Indian Academy of Sciences (India)

    M Aulice Scibioh; P V Ragini; S Rani; V R Vijayaraghavan; B Viswanathan

    2001-08-01

    With the aim of finding a suitable electrocatalyst for the efficient reduction of carbon dioxide, the electrochemistry of nickel (II) complex of 1,3,6,9,11,14-hexaazatricyclo [12 2 1 1] octadecane was studied using cyclic voltammetry (CV) and controlled-potential electrolysis (CPE) techniques in the presence and absence of CO2 in 100% H2O, CH3CN-H2O mixtures (20-100%) and DMF-H2O (70-100%) mixtures. The efficiency of this process is determined using the coulometry technique. CO is the major product in the gaseous phase and HCOOH the sole product formed in the solution phase.

  18. Selectivity Control of CO2 Reduction in an Inorganic Artificial Photosynthesis System

    Science.gov (United States)

    Hashiba, Hiroshi; Yotsuhashi, Satoshi; Deguchi, Masahiro; Yamada, Yuka; Ohkawa, Kazuhiro

    2013-09-01

    We demonstrated that the selectivity of photo electrochemical CO2 reduction can be controlled in an inorganic artificial photosynthesis system using an AlGaN/GaN photo electrode. By increasing input light intensity and the use of a gold cathode, the Faradaic efficiency of CO dramatically increases from 30% to over 80% while that of H2 decreases. We observed that the cathode potential resulting from illumination determines the ratio of CO and H2. With this system, it is possible to switch the main reaction product from CO to HCOOH, which is also effective even under intense illumination.

  19. Efficient Electrocatalytic Reduction of CO2 by Nitrogen-Doped Nanoporous Carbon/Carbon Nanotube Membranes - A Step Towards the Electrochemical CO2 Refinery

    KAUST Repository

    Wang, Hong

    2017-05-12

    The search for earth abundant, efficient and stable electrocatalysts that can enable the chemical reduction of CO2 to value-added chemicals and fuels at an industrially relevant scale, is a high priority for the development of a global network of renewable energy conversion and storage systems that can meaningfully impact greenhouse gas induced climate change. Here we introduce a straightforward, low cost, scalable and technologically relevant method to manufacture an all-carbon, electroactive, nitrogen-doped nanoporous carbon-carbon nanotube composite membrane. The membrane is demonstrated to function as a binder-free, high-performance electrode for the electrocatalytic reduction of CO2 to formate. The Faradaic efficiency for the production of formate is 81%. Furthermore, the robust structural and electrochemical properties of the membrane endow it with excellent long-term stability.

  20. Spinal cord transection inhibits HR reduction in anesthetized rats immersed in an artificial CO2-hot spring bath

    Science.gov (United States)

    Yamamoto, Noriyuki; Hashimoto, Masaaki

    2007-01-01

    Like humans, the heart rate (HR) of anesthetized rats immersed in CO2-water is lower than that when immersed in tap water at the same temperature. To investigate the afferent signal pathway in the mechanism of HR reduction, Wistar rats were anesthetized with urethane and then the spinal cord was transected between T4 and T5. The animals were immersed up to the axilla in a bathtub of tap-water (CO2 contents: 10 20 mg·l-1) or of CO2-water (965 1,400 mg·l-1) at 35°C while recording HR, arterial blood pressure, and arterial blood gas parameters ( PaCO2, PaO2, pH). Arterial blood gas parameters did not change during immersion, irrespective of CO2 concentration of the bath water, whereas the HR was reduced in the CO2-water bath. The inhalation of CO2-mixed gas (5 % CO2, 20 % O2, 75 % N2) resulted in increased levels of blood gases and an increased HR during immersion in all types of water tested. The HR reduction observed in sham transected control animals immersed in CO2-water disappeared after subsequent spinal cord transection. These results show that the dominant afferent signal pathway to the brain, which is involved in inducing the reduced HR during immersion in CO2-water, is located in the neuronal route and not in the bloodstream.

  1. Low Temperature Performance of Selective Catalytic Reduction of NO with NH3 under a Concentrated CO2 Atmosphere

    Directory of Open Access Journals (Sweden)

    Xiang Gou

    2015-10-01

    Full Text Available Selective catalytic reduction of NOx with NH3 (NH3-SCR has been widely investigated to reduce NOx emissions from combustion processes, which cause environmental challenges. However, most of the current work on NOx reduction has focused on using feed gas without CO2 or containing small amounts of CO2. In the future, oxy-fuel combustion will play an important role for power generation, and this process generates high concentrations of CO2 in flue gas. Therefore, studies on the SCR process under concentrated CO2 atmosphere conditions are important for future SCR deployment in oxy-fuel combustion processes. In this work, Mn- and Ce-based catalysts using activated carbon as support were used to investigate the effect of CO2 on NO conversion. A N2 atmosphere was used for comparison. Different process conditions such as temperature, SO2 concentration, H2O content in the feed gas and space velocity were studied. Under Mn-Ce/AC conditions, the results suggested that Mn metal could reduce the inhibition effect of CO2 on the NO conversion, while Ce metal increased the inhibition effect of CO2. High space velocity also resulted in a reduction of CO2 inhibition on the NO conversion, although the overall performance of SCR was greatly reduced at high space velocity. Future investigations to design novel Mn-based catalysts are suggested to enhance the SCR performance under concentrated CO2 atmosphere conditions.

  2. Copper-Based Metal-Organic Porous Materials for CO2 Electrocatalytic Reduction to Alcohols.

    Science.gov (United States)

    Albo, Jonathan; Vallejo, Daniel; Beobide, Garikoitz; Castillo, Oscar; Castaño, Pedro; Irabien, Angel

    2017-03-22

    The electrocatalytic reduction of CO2 has been investigated using four Cu-based metal-organic porous materials supported on gas diffusion electrodes, namely, (1) HKUST-1 metal-organic framework (MOF), [Cu3 (μ6 -C9 H3 O6 )2 ]n ; (2) CuAdeAce MOF, [Cu3 (μ3 -C5 H4 N5 )2 ]n ; (3) CuDTA mesoporous metal-organic aerogel (MOA), [Cu(μ-C2 H2 N2 S2 )]n ; and (4) CuZnDTA MOA, [Cu0.6 Zn0.4 (μ-C2 H2 N2 S2 )]n . The electrodes show relatively high surface areas, accessibilities, and exposure of the Cu catalytic centers as well as favorable electrocatalytic CO2 reduction performance, that is, they have a high efficiency for the production of methanol and ethanol in the liquid phase. The maximum cumulative Faradaic efficiencies for CO2 conversion at HKUST-1-, CuAdeAce-, CuDTA-, and CuZnDTA-based electrodes are 15.9, 1.2, 6, and 9.9 %, respectively, at a current density of 10 mA cm(-2) , an electrolyte-flow/area ratio of 3 mL min cm(-2) , and a gas-flow/area ratio of 20 mL min cm(-2) . We can correlate these observations with the structural features of the electrodes. Furthermore, HKUST-1- and CuZnDTA-based electrodes show stable electrocatalytic performance for 17 and 12 h, respectively. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. CO2 Reduction Assembly Prototype Using Microlith-Based Sabatier Reactor for Ground Demonstration

    Science.gov (United States)

    Junaedi, Christian; Hawley, Kyle; Walsh, Dennis; Roychoudhury, Subir; Abney, Morgan B.; Perry, Jay L.

    2014-01-01

    The utilization of CO2 to produce life support consumables, such as O2 and H2O, via the Sabatier reaction is an important aspect of NASA's cabin Atmosphere Revitalization System (ARS) and In-Situ Resource Utilization (ISRU) architectures for both low-earth orbit and long-term manned space missions. Carbon dioxide can be reacted with H2, obtained from the electrolysis of water, via Sabatier reaction to produce methane and H2O. Methane can be stored and utilized as propellant while H2O can be either stored or electrolyzed to produce oxygen and regain the hydrogen atoms. Depending on the application, O2 can be used to replenish the atmosphere in human-crewed missions or as an oxidant for robotic and return missions. Precision Combustion, Inc. (PCI), with support from NASA, has previously developed an efficient and compact Sabatier reactor based on its Microlith® catalytic technology and demonstrated the capability to achieve high CO2 conversion and CH4 selectivity (i.e., =90% of the thermodynamic equilibrium values) at high space velocities and low operating temperatures. This was made possible through the use of high-heat-transfer and high-surface-area Microlith catalytic substrates. Using this Sabatier reactor, PCI designed, developed, and demonstrated a stand-alone CO2 Reduction Assembly (CRA) test system for ground demonstration and performance validation. The Sabatier reactor was integrated with the necessary balance-of-plant components and controls system, allowing an automated, single "push-button" start-up and shutdown. Additionally, the versatility of the test system prototype was demonstrated by operating it under H2-rich (H2/CO2 of >4), stoichiometric (ratio of 4), and CO2-rich conditions (ratio of water recovery rates. In this paper, the development of the CRA test system for ground demonstration will be discussed. Additionally, the performance results from testing the system at various operating conditions and the results from durability testing will be

  4. Reduced graphene oxide as photocatalyst for CO2 reduction reaction(Conference Presentation)

    Science.gov (United States)

    Chang, Yu-Chung

    2016-10-01

    Photocatalytic conversion of carbon dioxide (CO2) to hydrocarbons such as methanol makes possible simultaneous solar energy harvesting and CO2 reduction. Our previous work is using graphene oxide (GO) as a promising photocatalyst for photocatalytic conversion of CO2 to methanol[1].When using graphene oxide as photocatalyst, the photocatalytic efficiency is 4-flod higher than TiO2 powder. GO has a lot of defects on the surface and those defects make sp2 carbon structure become sp3 carbon structure. The carbon structure change cause the GO has large energy gap about 2.7 eV to 3.2 eV. In order to remove the defect and reduce the energy gap of GO, Zhao et al. try to annealing GO powder in the nitrogen atmosphere at 900oC, the GO structure can be reduced to near graphene structure[2]. Zhu et al. do some low temperature annealing, it can control the structure and energy bandgap of GO by control annealing temperature. If the annealing temperature increase the bandgap of GO will be reduce[3]. So, we can using this annealing process to reduce the bandgap of the GO. In the varying temperature thermal reduction process, as the temperature increases from 130oC to 170oC, the functional groups of the graphene oxide will be reduced and band gap of graphene oxide will be narrowed at same time. The characteristic of thermal reduced graphene oxide were analyzed by SEM, XRD and Raman measurements. The band position was determined by UV/Vis. The reduction of functional groups correlates to red shift in light absorption and eventual quenching in the PL signal of RGOs. Combining hydrophobicity, light harvesting and PL quench, we get the highest yield of RGO150 (0.31 μmole g-1 -cat hr-1) is 1.7-fold higher than that of GO (0.18μmole g-1 -cat hr-1). This work investigates a modified method for using a thermal reduction process to reduce the energy gap of graphene oxide.

  5. Effects of elevated CO2 and nitrogen deposition on ecosystem carbon fluxes on the Sanjiang plain wetland in Northeast China.

    Directory of Open Access Journals (Sweden)

    Jianbo Wang

    Full Text Available BACKGROUND: Increasing atmospheric CO2 and nitrogen (N deposition across the globe may affect ecosystem CO2 exchanges and ecosystem carbon cycles. Additionally, it remains unknown how increased N deposition and N addition will alter the effects of elevated CO2 on wetland ecosystem carbon fluxes. METHODOLOGY/PRINCIPAL FINDINGS: Beginning in 2010, a paired, nested manipulative experimental design was used in a temperate wetland of northeastern China. The primary factor was elevated CO2, accomplished using Open Top Chambers, and N supplied as NH4NO3 was the secondary factor. Gross primary productivity (GPP was higher than ecosystem respiration (ER, leading to net carbon uptake (measured by net ecosystem CO2 exchange, or NEE in all four treatments over the growing season. However, their magnitude had interannual variations, which coincided with air temperature in the early growing season, with the soil temperature and with the vegetation cover. Elevated CO2 significantly enhanced GPP and ER but overall reduced NEE because the stimulation caused by the elevated CO2 had a greater impact on ER than on GPP. The addition of N stimulated ecosystem C fluxes in both years and ameliorated the negative impact of elevated CO2 on NEE. CONCLUSION/SIGNIFICANCE: In this ecosystem, future elevated CO2 may favor carbon sequestration when coupled with increasing nitrogen deposition.

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

    KAUST Repository

    Morlanés, Natalia

    2016-04-12

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

  7. Spinel Metal Oxide-Alkali Carbonate-Based, Low-Temperature Thermochemical Cycles for Water Splitting and CO_2 Reduction

    OpenAIRE

    Xu, Bingjun; Bhawe, Yashodhan; Davis, Mark E.

    2013-01-01

    A manganese oxide-based, thermochemical cycle for water splitting below 1000 °C has recently been reported. The cycle involves the shuttling of Na+ into and out of manganese oxides via the consumption and formation of sodium carbonate, respectively. Here, we explore the combinations of three spinel metal oxides and three alkali carbonates in thermochemical cycles for water splitting and CO_2 reduction. Hydrogen evolution and CO_2 reduction reactions of metal oxides with a given alkali carbona...

  8. Low Temperature Performance of Selective Catalytic Reduction of NO with NH3 under a Concentrated CO2 Atmosphere

    OpenAIRE

    Xiang Gou; Chunfei Wu; Kai Zhang; Guoyou Xu; Meng Si; Yating Wang; Enyu Wang; Liansheng Liu; Jinxiang Wu

    2015-01-01

    Selective catalytic reduction of NOx with NH3 (NH3-SCR) has been widely investigated to reduce NOx emissions from combustion processes, which cause environmental challenges. However, most of the current work on NOx reduction has focused on using feed gas without CO2 or containing small amounts of CO2. In the future, oxy-fuel combustion will play an important role for power generation, and this process generates high concentrations of CO2 in flue gas. Therefore, studies on the SCR process unde...

  9. The KCaSrTa5O15 photocatalyst with tungsten bronze structure for water splitting and CO2 reduction.

    Science.gov (United States)

    Takayama, Tomoaki; Tanabe, Kentaro; Saito, Kenji; Iwase, Akihide; Kudo, Akihiko

    2014-11-28

    KCaSrTa5O15 with tungsten bronze structure and a band gap of 4.1 eV showed activity for water splitting without cocatalysts. The activity was improved by loading the NiO cocatalyst. The apparent quantum yield of optimized NiO-loaded KCaSrTa5O15 was 2.3% at 254 nm for water splitting. When CO2 gas was bubbled into the reactant aqueous solution, Ag cocatalyst-loaded KCaSrTa5O15 produced CO and H2 as reduction products of CO2 and H2O, respectively, and O2 as an oxidation product of H2O. The carbon source of CO was confirmed to be CO2 molecules by using (13)CO2. The ratio of the number of electrons to that of holes calculated from the amounts of products (CO, H2 and O2) was almost unity. Additionally, the ratio of the turnover number of electrons consumed for CO production to the total number of an Ag atom of the cocatalyst that was the active site for CO2 reduction was 8.6 at 20 h. These results indicate that water was consumed as an electron donor for this photocatalytic CO2 reduction in an aqueous medium. Thus, KCaSrTa5O15 with tungsten bronze structure has arisen as a new photocatalyst that is active for water splitting and CO2 reduction utilizing water as an electron donor.

  10. Monodisperse Au nanoparticles for selective electrocatalytic reduction of CO2 to CO.

    Science.gov (United States)

    Zhu, Wenlei; Michalsky, Ronald; Metin, Önder; Lv, Haifeng; Guo, Shaojun; Wright, Christopher J; Sun, Xiaolian; Peterson, Andrew A; Sun, Shouheng

    2013-11-13

    We report selective electrocatalytic reduction of carbon dioxide to carbon monoxide on gold nanoparticles (NPs) in 0.5 M KHCO3 at 25 °C. Among monodisperse 4, 6, 8, and 10 nm NPs tested, the 8 nm Au NPs show the maximum Faradaic efficiency (FE) (up to 90% at -0.67 V vs reversible hydrogen electrode, RHE). Density functional theory calculations suggest that more edge sites (active for CO evolution) than corner sites (active for the competitive H2 evolution reaction) on the Au NP surface facilitates the stabilization of the reduction intermediates, such as COOH*, and the formation of CO. This mechanism is further supported by the fact that Au NPs embedded in a matrix of butyl-3-methylimidazolium hexafluorophosphate for more efficient COOH* stabilization exhibit even higher reaction activity (3 A/g mass activity) and selectivity (97% FE) at -0.52 V (vs RHE). The work demonstrates the great potentials of using monodisperse Au NPs to optimize the available reaction intermediate binding sites for efficient and selective electrocatalytic reduction of CO2 to CO.

  11. Reduction of CO2-TO-graphite conversion time of organic materials for 14C AMS

    DEFF Research Database (Denmark)

    Thomsen, M.S.; Gulliksen, S.

    1992-01-01

    that reduces the impurity content of CO2 produced by combustion of organic material. We found that using water during combustion reduces the average time for graphite conversion of CO2 from organic matter from >3 h to ca. 2 h. This is the time for graphite production from CO2 obtained by acid hydrolysis...

  12. Photo-reduction of CO2 Using a Rhenium Complex Covalently Supported on a Graphene/TiO2 Composite.

    Science.gov (United States)

    Cui, Shi-Cong; Sun, Xue-Zhong; Liu, Jin-Gang

    2016-07-07

    One of the promising solutions for decreasing atmospheric CO2 is artificial photosynthesis, in which CO2 can be photoconverted into solar fuels. In this study, a rhenium complex Re(PyBn)(CO)3 Cl (PyBn=1-(2-picolyl)-4-phenyl-1H-1,2,3-triazole) was covalently grafted onto the surface of reduced graphene oxide (rGO). This was further combined with TiO2 to fabricate a novel catalyst composite TiO2 -rGO-Re(PyBn)(CO)3 Cl for CO2 photo-reduction. This hybrid composite demonstrated high selectivity conversion of CO2 into CO under xenon-lamp irradiation. Compared with the unsupported homogeneous catalyst Re(PyBn)(CO)3 Cl, the covalent immobilized catalyst composite TiO2 -rGO-Re(PyBn)(CO)3 Cl enhanced the turnover number six times and significantly improved catalyst stability. During the process of CO2 photo-reduction, intermediate species with lifetimes longer than hundreds of microseconds were observed and the formation of CO products was revealed using timeresolved infrared spectroscopy. A plausible mechanism for CO2 photo-reduction by the TiO2 -rGO-Re(PyBn)(CO)3 Cl catalyst composite has been suggested. The obtained results have implications for the future design of efficient catalyst composites for CO2 photo-conversion.

  13. Photocatalytic Reduction of CO2 over Heterostructure Semiconductors into Value-Added Chemicals.

    Science.gov (United States)

    Guo, Ling-Ju; Wang, Yan-Jie; He, Tao

    2016-08-01

    Photoreduction of CO2 , which utilizes solar energy to convert CO2 into hydrocarbons, can be an effective means to overcome the increasing energy crisis and mitigate the rising emissions of greenhouse gas. This article covers recent advances in the CO2 photoreduction over heterostructure-based photocatalysts. The fundamentals of CO2 photoreduction and classification of the heterostructured photocatalysts are discussed first, followed by the latest work on the CO2 photoreduction over heterostructured photocatalysts in terms of the classification of the coupling semiconductors. Finally, a brief summary and a perspective on the challenges in this area are presented.

  14. The postural reduction in middle cerebral artery blood velocity is not explained by PaCO2

    DEFF Research Database (Denmark)

    Immink, R V; Secher, N H; Roos, C M

    2006-01-01

    In the normocapnic range, middle cerebral artery mean velocity (MCA Vmean) changes approximately 3.5% per mmHg carbon-dioxide tension in arterial blood (PaCO2) and a decrease in PaCO2 will reduce the cerebral blood flow by vasoconstriction (the CO2 reactivity of the brain). When standing up MCA...... Vmean and the end-tidal carbon-dioxide tension (PETCO2) decrease, suggesting that PaCO2 contributes to the reduction in MCA Vmean. In a fixed body position, PETCO2 tracks changes in the PaCO2 but when assuming the upright position, cardiac output (Q) decreases and its distribution over the lung changes...

  15. Reduction of CO 2 concentration in a zinc/air battery by absorption in a rotating packed bed

    Science.gov (United States)

    Cheng, Hsu-Hsiang; Tan, Chung-Sung

    The reduction of CO 2 concentration in a gas stream containing 500 ppm of CO 2 by a technique combining chemical absorption with Higee (high gravity) was investigated in this study. Using a 2.0 L aqueous amine-based solution to treat the feed gas with a flow rate which varied from 12.9 to 20.6 L min -1, piperazine (PZ) was found to be more effective than 2-(2-aminoethylamino) ethanol (AEEA) and monoethanolamine (MEA) for reducing the CO 2 concentration to a level below 20 ppm. The effects of temperature, rotating speed, amine solution flow rate, and gas flow rate on the removal efficiency of CO 2 were systematically examined. The results indicated that the proposed compact device could effectively reduce CO 2 to a level below 20 ppm, as required by a zinc/air battery, for a long period of time using PZ and its mixture with AEEA and MEA as the absorbents.

  16. Technology priorities for transport in Asia: assessment of economy-wide CO2 emissions reduction for Lebanon

    DEFF Research Database (Denmark)

    Dhar, Subash; Marpaung, Charles O. P.

    2015-01-01

    mitigations actions (NAMA) given their strong contribution for development and therefore a methodology based on in-put out-put decomposition analysis is proposed for analysing economy wide CO2 emissions reductions. The methodology has been applied for the transport sector of Lebanon where alternative fuels......,improvement to cars (private and taxis) and buses for public transport were prioritized by stakeholders. The economy-wide CO2 emission reduce by 2,269 thousand tons by 2020 if the prioritized technologies are implemented in Lebanon. Fuel mix effect and structural effect would reduce CO2 emission by 2,611 thousand...

  17. Preparation of copper oxide modified boron-doped diamond electrodes and its preliminary study for CO2 reduction

    Science.gov (United States)

    Yetri, N. Y.; Ivandini, T. A.; Gunlazuardi, J.

    2017-04-01

    Preparation of boron-doped diamond (BDD) modified with Cu2O (Cu2O-BDD) electrodes was conducted to study the electrochemical reduction of CO2. The electrodes were prepared by electrochemical reduction using a solution containing 1mM Cu(CH3COO)2 and 0.1 M CH3COONa (1:1) at pH 5.7 for 60 s. The electrodeposition of Cu2O at BDD surface was performed by chronoamperometry technique at -0.4 V (vs Ag/AgCl). SEM-EDS and XPS were utilized to characterize the electrodes. At Cu2O-BDD electrodes, cyclic voltammetry of dissolved CO2 in 0.1 M NaCl solution exhibited a reduction peak at around -1.3 V (vs Ag/AgCl), indicated the possibility for application in electrochemical reduction of CO2.

  18. Electrochemical CO2 reduction on Cu2O-derived copper nanoparticles: Controlling the catalytic selectivity of hydrocarbons

    NARCIS (Netherlands)

    Kas, Recep; Kortlever, R.; Milbrat, Alexander; Koper, M.T.M.; Mul, Guido; Baltrusaitis, Jonas

    2014-01-01

    The catalytic activity and hydrocarbon selectivity in electrochemical carbon dioxide (CO2) reduction on cuprous oxide (Cu2O) derived copper nanoparticles is discussed. Cuprous oxide films with [100], [110] and [111] orientation and variable thickness were electrodeposited by reduction of copper(II)

  19. Metal-free Nanoporous Carbon as a Catalyst for Electrochemical Reduction of CO2 to CO and CH4.

    Science.gov (United States)

    Li, Wanlu; Seredych, Mykola; Rodríguez-Castellón, Enrique; Bandosz, Teresa J

    2016-03-21

    S-doped and dual S,N-doped polymer-derived carbons were studied as electrocatalysts for the reduction of CO2. Higher Faradaic efficiencies for conversion to CO and CH4 were obtained for S,N-doped carbon than its S-doped counterpart. The former showed a maximum Faradaic efficiency of 11.3% for CO and 0.18% for CH4 formation. The S,N-nanoporous carbon was better at decreasing the overpotential of the reduction process. The pyridinic nitrogen groups were found to be actively participating in binding CO2. The quaternary nitrogen and thiophenic groups were also involved in the reduction process. It is proposed that the positively charged sites on the carbon atoms, adjacent to pyridinic nitrogen, stabilize the CO2(.-) and COOH* intermediates, promoting the formation of CO. The surface basicity of the catalysts improved the CO2 reduction selectivity when competing with H2 evolution. N2 adsorption measurements suggested that ultra-micropores enhance the reduction of CO2 to CH4.

  20. Contribution of winter fluxes to the annual CH4, CO2 and N2O emissions from freshwater marshes in the Sanjiang Plain

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Wetlands at the interface of the terrestrial and aquatic ecosystems are intensive sites for mineralization of organic matter,but the contribution of winter season fluxes of CH4, CO2 and N2O from wetland ecosystems to annual budgets is poorly known. By using the static opaque chamber and GC techniques, fluxes of CH4, CO2 and N2O at two freshwater marshes in the Sanjiang Plain were measured during the winter seasons of 2002/2003 and 2003/2004 with contrasting snow conditions and flooding regimes. The results showed that there were significant interannual and spatial differences in CH4, CO2 and N2O fluxes. The Carex lasiocarpa marsh emitted more CH4 and CO2 while absorbed less N2O than the Deyeuxia angustifolia marsh during the winter seasons. Over the winter season,emissions of CH4, CO2 and N2O ranged from 0.42 to 2.41 gC/m2, from 24.13 to 50.16 gC/m2, and from -25.20 to -148.96 mgN/m2,respectively. The contributions of winter season CH4 and CO2 emission to the annual budgets were 2.32%-4.62% and 22.17%-27.97%, respectively. Marshes uptake N2O during the freezing period, while release N2O during the thawing period. The winter uptake equaled to 13.70%-86.69% of the growing-season loss. We conclude that gas exchange between soil/snow and the atmosphere in the winter season contributed greatly to the annual budgets and cannot be ignored in a cool temperate freshwater marsh in Northeast China.

  1. Energy in the Netherlands. Optimized pathways to CO2 reduction in the Dutch context

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-09-15

    This document reports the findings of research undertaken by the Energy Forum NL (EFNL) which consists of companies active in different parts of the energy sector. The group strives for a more long-term, stable energy policy and investment climate in the Netherlands, one that will help realize overall climate ambitions. This report is part of the group's contribution to the energy debate in the Netherlands; it lays out a fact-based, objective analysis of the potential energy mix if one assumes a continued focus on carbon abatement. In this report, the Energy Forum NL provides pathways that show how the Netherlands can best contribute to the EU target of 80% CO2e emission reduction by 2050 compared to 1990. They particularly focus on the goal for the next 20 years: reducing CO2e emissions by 40% by 2030 compared to 1990. The Forum selected 40% as a midway target for 80% in 2050; this falls within the EU ambition of 40%-44% in 2030.1 The period beyond 2030, which is much more uncertain, is modeled in less detail. However, the Forum took care to not let the choice of any pathway during 2010-2030 lock a pathway after 2030 in or out. A 'least cost' approach, which works across sectors, is used to reduce emissions. In a 'least cost' approach, all emission reduction measures are ranked on costs and implemented progressively (starting from the cheapest) until the targeted abatement level is reached. In addition, a few developing technologies are implemented even if they are more expensive than alternatives. This choice prevents technology lock-in, ensures a more versatile, resilient energy system and provides a reasonable starting position for the period post-2030. The report assumes a pan-European approach for the power sector, which is the key sector in the Emissions Trading Scheme (ETS); in this case, Dutch abatement options 'compete' with those in other EU countries. For the other sectors it uses a national approach. Non-cost factors

  2. Reduction of Bromate by Cobalt-Impregnated Biochar Fabricated via Pyrolysis of Lignin Using CO2 as a Reaction Medium.

    Science.gov (United States)

    Cho, Dong-Wan; Kwon, Gihoon; Ok, Yong Sik; Kwon, Eilhann E; Song, Hocheol

    2017-04-19

    In this study, pyrolysis of lignin impregnated with cobalt (Co) was conducted to fabricate a Co-biochar (i.e., Co/lignin biochar) for use as a catalyst for bromate (BrO3(-)) reduction. Carbon dioxide (CO2) was employed as a reaction medium in the pyrolysis to induce desired effects associated with CO2; (1) the enhanced thermal cracking of volatile organic compounds (VOCs) evolved from the thermal degradation of biomass, and (2) the direct reaction between CO2 and VOCs, which resulted in the enhanced generation of syngas (i.e., H2 and CO). This study placed main emphases on three parts: (1) the role of impregnated Co in pyrolysis of lignin in the presence of CO2, (2) the characterization of Co/lignin biochar, and (3) evaluation of catalytic capability of Co-lignin biochar in BrO3(-) reduction. The findings from the pyrolysis experiments strongly evidenced that the desired CO2 effects were strengthened due to catalytic effect of impregnated Co in lignin. For example, the enhanced generation of syngas from pyrolysis of Coimpregnated lignin in CO2 was more significant than the case without Co impregnation. Moreover, pyrolysis of Coimpregnated lignin in CO2 led to production of biochar of which surface area (599 m(2) g(-1)) is nearly 100 times greater than the biochar produced in N2 (6.6 m(2) g(-1)). Co/lignin biochar produced in CO2 also showed a great performance in catalyzing BrO3(-) reduction as compared to the biochar produced in N2.

  3. A highly selective copper-indium bimetallic electrocatalyst for the electrochemical reduction of aqueous CO2to CO

    KAUST Repository

    Rasul, Shahid

    2014-12-23

    The challenge in the electrochemical reduction of aqueous carbon dioxide is in designing a highly selective, energy-efficient, and non-precious-metal electrocatalyst that minimizes the competitive reduction of proton to form hydrogen during aqueous CO2 conversion. A non-noble metal electrocatalyst based on a copper-indium (Cu-In) alloy that selectively converts CO2 to CO with a low overpotential is reported. The electrochemical deposition of In on rough Cu surfaces led to Cu-In alloy surfaces. DFT calculations showed that the In preferentially located on the edge sites rather than on the corner or flat sites and that the d-electron nature of Cu remained almost intact, but adsorption properties of neighboring Cu was perturbed by the presence of In. This preparation of non-noble metal alloy electrodes for the reduction of CO2 provides guidelines for further improving electrocatalysis.

  4. An Incentive-Based Solution of Sustainable Mobility for Economic Growth and CO2 Emissions Reduction

    Directory of Open Access Journals (Sweden)

    Manuel Herrador

    2015-05-01

    Full Text Available “Incentivized Sustainable Mobility” is a conceptual business model which involves four stakeholders: citizens, municipalities, commerce and mobility services. A platform named “ISUMO” (Incentivized Sustainable Mobility provides technological support to this business model, integrating a set of metaservices that unifies the existing ICTs of transportation plus a unique patented QR-based (Quick Response low-cost charging device for electric vehicles. Essentially, the system tracks and registers citizens’ transportation activities (anonymously and voluntarily and evaluates each through a scoring system while their ecological footprint is calculated. Afterwards, citizens are able to exchange their accumulated points for discount QR coupons, to be redeemed in the associated commerce in order to purchase their products or services. The breakthrough of this business model is that it enhances awareness of sustainable mobility practices, increasing their attractiveness as perceived by the stakeholders with diverse benefits; citizens (and indirectly, the municipalities initiate a new consumption pattern of “coupons culture” linked to sustainable mobility, the urban economy is stimulated, and the use of mobility services grows, providing a new business opportunity regarding electric vehicles. It is expected that continuous exploration of the model and implementation will contribute to sustainable social and economic development aiming at CO2 emissions reduction, headline targets of the Europe 2020 strategy.

  5. Highly efficient supramolecular photocatalysts for CO2 reduction using visible light.

    Science.gov (United States)

    Sato, Shunsuke; Koike, Kazuhide; Inoue, Haruo; Ishitani, Osamu

    2007-04-01

    We report the most efficient homogeneous photocatalyst yet for CO(2) reduction using a wide range of visible-light wavelength. We synthesized new Ru(II)-Re(I) binuclear complexes with 1,3-bis(4'-methyl-[2,2']bipyridinyl-4-yl)-propan-2-ol (bpyC3bpy) as a bridge ligand, specifically [Ru-ReP(OEt)(3)](3+) and [Ru-Repy](3+) where a P(OEt)(3) or pyridine ligand coordinates on the Re site. Their photocatalytic activities were compared with [Ru-ReCl](2+), which has a Cl(-) ligand on the Re site and has recently been reported as a much better photocatalyst (Phi = 0.12, TN(CO) = 160) than a 1:1 mixed system of the corresponding Ru(II) and Re(I) mononuclear complexes. The best photocatalyst was [Ru-ReP(OEt)(3)](3+), for which Phi = 0.21 and TN(CO) = 232. A mechanistic study clearly showed that [Ru-ReP(OEt)(3)](3+) is rapidly converted into the solvento complex [Ru-ReSol](3+), (Sol = DMF or TEOA) which is the actual photocatalyst. Although similar rapid ligand substitution occurs with other supramolecules, the pyridine and Cl(-) anions accelerate the decomposition of the supramolecular photocatalysts.

  6. Carbon dioxide sequestration by mineral carbonation. Feasibility of enhanced natural weathering as a CO2 emission reduction technology

    Energy Technology Data Exchange (ETDEWEB)

    Huijgen, W.J.J. [ECN Biomass, Coal and Environmental Research, Petten (Netherlands)

    2007-07-01

    A possible technology that can contribute to the reduction of carbon dioxide emissions is CO2 sequestration by mineral carbonation. The basic concept behind mineral CO2 sequestration is the mimicking of natural weathering processes in which calcium or magnesium containing minerals react with gaseous CO2 and form solid calcium or magnesium carbonates. Potential advantages of mineral CO2 sequestration compared to, e.g., geological CO2 storage include (1) the permanent and inherently safe sequestration of CO2, due to the thermodynamic stability of the carbonate product formed and (2) the vast potential sequestration capacity, because of the widespread and abundant occurrence of suitable feedstock. In addition, carbonation is an exothermic process, which potentially limits the overall energy consumption and costs of CO2 emission reduction. However, weathering processes are slow, with timescales at natural conditions of thousands to millions of years. For industrial implementation, a reduction of the reaction time to the order of minutes has to be achieved by developing alternative process routes. The aim of this thesis is an investigation of the technical, energetic, and economic feasibility of CO2 sequestration by mineral carbonation. In Chapter 1 the literature published on CO2 sequestration by mineral carbonation is reviewed. Among the potentially suitable mineral feedstock for mineral CO2 sequestration, Ca-silicates, more particularly wollastonite (CaSiO3), a mineral ore, and steel slag, an industrial alkaline solid residue, are selected for further research. Alkaline Ca-rich residues seem particularly promising, since these materials are inexpensive and available near large industrial point sources of CO2. In addition, residues tend to react relatively rapidly with CO2 due to their (geo)chemical instability. Various process routes have been proposed for mineral carbonation, which often include a pre-treatment of the solid feedstock (e.g., size reduction and

  7. Reduction of CO2 Emissions in Houses of Historic and Visual Importance

    NARCIS (Netherlands)

    Van Hal, A.; Dulski, B.; Postel, A.M.

    2010-01-01

    According to the ‘Climate Programme’ the municipality of Amsterdam has the ambition to reduce the CO2 emissions within the city limits by 40% in the year 2025 compared to the year 1990. To realize this ambition substantial CO2 savings have to be realized at the 375,000 current houses in the city. A

  8. Mass transfer characteristics in structured packing for CO2 emission reduction processes

    NARCIS (Netherlands)

    Van Elk, E. P.; Raynal, L.; Versteeg, G. F.; van Loo, S.

    2007-01-01

    Acid gas treating and CO2 capture from flue gas by absorption have gained wide importance over the past few decades. With the implementation of more stringent environmental regulations and the awareness of the greenhouse effect, the need for efficient removal of acid gases such as CO2 (carbon

  9. Incentives for subcontractors to adopt CO2 emission reporting and reduction techniques

    NARCIS (Netherlands)

    Scholtens, Bert; Kleinsmann, Renske

    2011-01-01

    We investigate the incentives for subcontractors (couriers) of a transport and logistics company to report about their CO2 emissions and to implement CO2 reducing technologies. Furthermore, we try to find out whether these incentives differ between British and Dutch couriers. We find that several in

  10. Mass transfer characteristics in structured packing for CO2 emission reduction processes

    NARCIS (Netherlands)

    Van Elk, E. P.; Raynal, L.; Versteeg, G. F.; van Loo, S.

    2007-01-01

    Acid gas treating and CO2 capture from flue gas by absorption have gained wide importance over the past few decades. With the implementation of more stringent environmental regulations and the awareness of the greenhouse effect, the need for efficient removal of acid gases such as CO2 (carbon dioxid

  11. A Consideration on Service Business Model for Saving Energy and Reduction of CO2 Emissions Using Inverters

    Science.gov (United States)

    Kosaka, Michitaka; Yabutani, Takashi

    This paper considers the effectiveness of service business approach for reducing CO2 emission. “HDRIVE” is a service business using inverters to reduce energy consumption of motor drive. The business model of this service is changed for finding new opportunities of CO2 emission reduction by combining various factors such as financial service or long-term service contract. Risk analysis of this business model is very important for giving stable services to users for long term. HDRIVE business model is found to be suitable for this objective. This service can be applied to the industries such as chemical or steel industry effectively, where CO2 emission is very large, and has the possibility of creating new business considering CDM or trading CO2 emission right. The effectiveness of this approach is demonstrated through several examples in real business.

  12. Can the envisaged reductions of fossil fuel CO2 emissions be detected by atmospheric observations?

    Science.gov (United States)

    Levin, Ingeborg; Rödenbeck, Christian

    2008-03-01

    The lower troposphere is an excellent receptacle, which integrates anthropogenic greenhouse gases emissions over large areas. Therefore, atmospheric concentration observations over populated regions would provide the ultimate proof if sustained emissions changes have occurred. The most important anthropogenic greenhouse gas, carbon dioxide (CO(2)), also shows large natural concentration variations, which need to be disentangled from anthropogenic signals to assess changes in associated emissions. This is in principle possible for the fossil fuel CO(2) component (FFCO(2)) by high-precision radiocarbon ((14)C) analyses because FFCO(2) is free of radiocarbon. Long-term observations of (14)CO(2) conducted at two sites in south-western Germany do not yet reveal any significant trends in the regional fossil fuel CO(2) component. We rather observe strong inter-annual variations, which are largely imprinted by changes of atmospheric transport as supported by dedicated transport model simulations of fossil fuel CO(2). In this paper, we show that, depending on the remoteness of the site, changes of about 7-26% in fossil fuel emissions in respective catchment areas could be detected with confidence by high-precision atmospheric (14)CO(2) measurements when comparing 5-year averages if these inter-annual variations were taken into account. This perspective constitutes the urgently needed tool for validation of fossil fuel CO(2) emissions changes in the framework of the Kyoto protocol and successive climate initiatives.

  13. Enhanced selective photocatalytic CO2 reduction into CO over Ag/CdS nanocomposites under visible light

    Science.gov (United States)

    Zhu, Zezhou; Qin, Jiani; Jiang, Min; Ding, Zhengxin; Hou, Yidong

    2017-01-01

    Photocatalytic reduction of carbon dioxide can convert chemically inert carbon dioxide into useful chemical fuel in a mild manner. Herein, Ag-CdS nanocomposites were prepared by photodeposition method and examined for photocatalytic CO2 reduction under visible light. Meanwhile, the nanocomposites were characterized by XRD, SEM, TEM, XPS, DRS and PL in detail. The results show that, the deposition of Ag improves the photocatalytic performance of CdS, especially in the selectivity of CO2-to-CO. The highest photocatalytic activity is achieved over 1.0 wt.% Ag/CdS, with an increase by 3 times in comparison to CdS. In this reaction system, Ag can serve as electron trap as well as active site for CO2 reduction, which is probably responsible for the enhanced activity and selectivity of CO2 to CO over Ag/CdS. The possible mechanism of CO2 photoreduction over Ag/CdS was proposed in view of the abovementioned analysis.

  14. Novel Catalytic Reactor for CO2 Reduction via Sabatier Process Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Precision Combustion, Inc. (PCI) proposes to develop a novel, efficient, and lightweight catalytic Sabatier CO2 methanation unit, capable of converting a mixture of...

  15. Respiratory Dialysis: Reduction in Dependence on Mechanical Ventilation by Venovenous Extracorporeal CO2 Removal

    Science.gov (United States)

    2011-06-01

    console. Arterial tension of oxy- gen ( PaO2 , mm Hg) and CO2 (PaCO2, mm Hg) were measured at baseline, 2 hrs after insertion of the Hemolung and every 6 hrs... PaO2 was lower at 2 hrs, whereas PaCO2 was higher at 48 and 72 hrs after inser- tion when compared to baseline values (Table 1). The pH was unchanged...Tidal volume, mL 650 14 556 24 576 9 574 15 578 15 .087 .084 .16 .18 PaO2 , mm Hg 96 2 77 5 a 103 8 97 16 112 8 .04 .94 .55 .08 PaCO2

  16. Faraday efficiency and mechanism of electrochemical surface reactions: CO2 reduction and H2 formation on Pt(111).

    Science.gov (United States)

    Hussain, Javed; Jónsson, Hannes; Skúlason, Egill

    2016-12-22

    An atomic scale model of the electrical double layer is used to calculate the mechanism and rate of electrochemical reduction of CO2 as well as H2 formation at a Pt(111) electrode. The water layer contains solvated protons and the electrode has excess electrons at the surface. Density functional theory within the generalized gradient approximation is used to describe the electronic structure while the mechanism and activation energy of the various elementary reactions is obtained by calculating minimum energy paths using the nudged elastic band method. The applied electrical potential is deduced from the calculated work function. The optimal reaction mechanism for CO2 reduction to either methane or methanol is found and the estimated rate compared with that of the competing reaction, H2 formation. When the free energy of only the intermediates and reactants is taken into account, not the activation energy, Pt(111) would seem to be a good electrocatalyst for CO2 reduction, significantly better than Cu(111). This, however, contradicts experimental findings. Detailed calculations reported here show that the activation energy for CO2 reduction is high for both Heyrovsky and Tafel mechanisms on Pt(111) in the relevant range of applied potential. The rate-limiting step of the Heyrovsky mechanism, *COOH + H(+) + e(-) → *CO + H2O, is estimated to have an activation energy of 0.95 eV at -0.9 V vs. standard hydrogen electrode. Under the same conditions, the activation energy for H2 formation is estimated to be only 0.5 eV. This explains why attempts to reduce CO2 using platinum electrodes have produced only H2. A comparison is made with analogous results for Cu(111) [J. Hussain et al., Procedia Comput. Sci., 2015, 51, 1865] where a reaction mechanism with low activation energy for CO2 electroreduction to methane was identified. The difference between the two electrocatalysts is discussed.

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

    KAUST Repository

    Chen, Jiawei

    2016-04-04

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

  18. Carbon Supported Engineering NiCo2O4 Hybrid Nanofibers with Enhanced Electrocatalytic Activity for Oxygen Reduction Reaction

    Directory of Open Access Journals (Sweden)

    Diab Hassan

    2016-09-01

    Full Text Available The design of cheap and efficient oxygen reduction reaction (ORR electrocatalysts is of a significant importance in sustainable and renewable energy technologies. Therefore, ORR catalysts with superb electrocatalytic activity and durability are becoming a necessity but still remain challenging. Herein, we report C/NiCo2O4 nanocomposite fibers fabricated by a straightforward electrospinning technique followed by a simple sintering process as a promising ORR electrocatalyst in alkaline condition. The mixed-valence oxide can offer numerous accessible active sites. In addition, the as-obtained C/NiCo2O4 hybrid reveals significantly remarkable electrocatalytic performance with a highly positive onset potential of 0.65 V, which is only 50 mV lower than that of commercially available Pt/C catalysts. The analyses indicate that C/NiCo2O4 catalyst can catalyze O2-molecules via direct four electron pathway in a similar behavior as commercial Pt/C catalysts dose. Compared to single NiCo2O4 and carbon free NiCo2O4, the C/NiCo2O4 hybrid displays higher ORR current and more positive half-wave potential. The incorporated carbon matrices are beneficial for fast electron transfer and can significantly impose an outstanding contribution to the electrocatalytic activity. Results indicate that the synthetic strategy hold a potential as efficient route to fabricate highly active nanostructures for practical use in energy technologies.

  19. A DFT-based genetic algorithm search for AuCu nanoalloy electrocatalysts for CO2 reduction

    DEFF Research Database (Denmark)

    Lysgaard, Steen; Mýrdal, Jón Steinar Garðarsson; Hansen, Heine Anton

    2015-01-01

    Using a DFT-based genetic algorithm (GA) approach, we have determined the most stable structure and stoichiometry of a 309-atom icosahedral AuCu nanoalloy, for potential use as an electrocatalyst for CO2 reduction. The identified core–shell nano-particle consists of a copper core interspersed...

  20. Chinese Public’s Willingness to Pay for CO2 Emissions Reductions: A Case Study from Four Provinces/Cities

    Directory of Open Access Journals (Sweden)

    Duan Hong-Xia

    2014-01-01

    Citation: Duan, H.-X., Lü, Y.-L., Li, Y., 2014. Chinese public’s willingness to pay for CO2 emissions reductions: A case study from four provinces/cities. Adv. Clim. Change Res. 5(2, doi: 10.3724/SP.J.1248.2014.100.

  1. NiCo2O4/N-doped graphene as an advanced electrocatalyst for oxygen reduction reaction

    Science.gov (United States)

    Zhang, Hui; Li, Huiyong; Wang, Haiyan; He, Kejian; Wang, Shuangyin; Tang, Yougen; Chen, Jiajie

    2015-04-01

    Developing low-cost catalyst for high-performance oxygen reduction reaction (ORR) is highly desirable. Herein, NiCo2O4/N-doped reduced graphene oxide (NiCo2O4/N-rGO) hybrid is proposed as a high-performance catalyst for ORR for the first time. The well-formed NiCo2O4/N-rGO hybrid is studied by cyclic voltammetry (CV) curves and linear-sweep voltammetry (LSV) performed on the rotating-ring-disk-electrode (RDE) in comparison with N-rGO-free NiCo2O4 and the bare N-rGO. Due to the synergistic effect, the NiCo2O4/N-rGO hybrid exhibits significant improvement of catalytic performance with an onset potential of -0.12 V, which mainly favors a direct four electron pathway in ORR process, close to the behavior of commercial carbon-supported Pt. Also, the benefits of N-incorporation are investigated by comparing NiCo2O4/N-rGO with NiCo2O4/rGO, where higher cathodic currents, much more positive half-wave potential and more electron transfer numbers are observed for the N-doping one, which should be ascribed to the new highly efficient active sites created by N incorporation into graphene. The NiCo2O4/N-rGO hybrid could be used as a promising catalyst for high power metal/air battery.

  2. Assessment of Energy Efficiency Improvement and CO2 Emission Reduction Potentials in India's Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, III, William R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hasanbeigi, Ali [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Xu, Tengfang [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-12-03

    India’s cement industry is the second largest in the world behind China with annual cement production of 168 Mt in 2010 which accounted for slightly greater than six percent of the world’s annual cement production in the same year. To produce that amount of cement, the industry consumed roughly 700 PJ of fuel and 14.7 TWh of electricity. We identified and analyzed 22 energy efficiency technologies and measures applicable to the processes in the Indian cement industry. The Conservation Supply Curve (CSC) used in this study is an analytical tool that captures both the engineering and the economic perspectives of energy conservation. Using a bottom-up electricity CSC model and compared to an electricity price forecast the cumulative cost-effective plant-level electricity savings potential for the Indian cement industry for 2010- 2030 is estimated to be 83 TWh, and the cumulative plant-level technical electricity saving potential is 89 TWh during the same period. The grid-level CO2 emissions reduction associated with cost-effective electricity savings is 82 Mt CO2 and the electric grid-level CO2 emission reduction associated with technical electricity saving potential is 88 Mt CO2. Compared to a fuel price forecast, an estimated cumulative cost-effective fuel savings potential of 1,029 PJ with associated CO2 emission reduction of 97 Mt CO2 during 2010-2030 is possible. In addition, a sensitivity analysis with respect to the discount rate used is conducted to assess the effect of changes in this parameter on the results. The result of this study gives a comprehensive and easy to understand perspective to the Indian cement industry and policy makers about the energy efficiency potential and its associated cost over the next twenty years.

  3. Inhibition by corrins of the ATP-dependent activation and CO2 reduction by the methylreductase system in Methanobacterium bryantii.

    Science.gov (United States)

    Whitman, W B; Wolfe, R S

    1987-01-01

    Corrins inhibited the ATP-dependent activation of the methylreductase system and the methyl coenzyme M-dependent reduction of CO2 in extracts of Methanobacterium bryantii resolved from low-molecular-weight factors. The concentrations of cobinamides and cobamides required for one-half of maximal inhibition of the ATP-dependent activation were between 1 and 5 microM. Cobinamides were more inhibitory at lower concentrations than cobamides. Deoxyadenosylcobalamin was not inhibitory at concentrations up to 25 microM. The inhibition of CO2 reduction was competitive with respect to CO2. The concentration of methylcobalamin required for one-half of maximal inhibition was 5 microM. Other cobamides inhibited at similar concentrations, but diaquacobinamide inhibited at lower concentrations. With respect to their affinities and specificities for corrins, inhibition of both the ATP-dependent activation and CO2 reduction closely resembled the corrin-dependent activation of the methylreductase described in similar extracts (W. B. Whitman and R. S. Wolfe, J. Bacteriol. 164:165-172, 1985). However, whether the multiple effects of corrins are due to action at a single site is unknown. PMID:3098736

  4. Studies of surface processes of electrocatalytic reduction of CO2 on Pt(210), Pt(310) and Pt(510)

    Institute of Scientific and Technical Information of China (English)

    FAN; ChunJie; FAN; YouJun; ZHEN; ChunHua; ZHENG; QingWei; SUN; ShiGang

    2007-01-01

    Surface processes of CO2 reduction on Pt(210), Pt(310), and Pt(510) electrodes were studied by cyclic voltammetry. Different surface structures of these platinum single crystal electrodes were obtained by various treatment conditions. The experimental results illustrated that the electrocatalytic activity of Pt single crystal electrodes towards CO2 reduction is decreased in an order of Pt(210)>Pt(310)>Pt(510), i.e., with the decrease of (110) step density on well-defined surfaces. When the surfaces were reconstructed due to oxygen adsorption, the catalytic activity of all the three electrodes has been enhanced to a certain extent. Although the activity order remains unchanged, the electrocatalytic activity has been enhanced more significantly as the density of (110) step sites is more intensive on the Pt single crystal surface. It has revealed that the more open the surface structure is, the more active the Pt single crystal electrode will be, and the easier for the electrode to be transformed into a surface structure that exhibits higher activity under external inductions. However, the relatively ordered surfaces of Pt single crystal electrode are comparatively stable under the same external inductions. The present study has gained knowledge on the interaction between CO2 and Pt single crystal electrode surfaces at a microscopic level, and thrown new insight into understanding the surface processes of electrocatalytic reduction of CO2.

  5. Photocatalytic Reduction of CO2 by Nano-Sized ZnS Supported on Silica and Polyvinyl Alcohol

    Institute of Scientific and Technical Information of China (English)

    陈静; 刘引烽; 桑文斌; 华家栋; 孟中岩

    2003-01-01

    Nanosized photocatalyst ZnS particles supported on silica and polyvinyl alcohol was successfully prepared by complex trans-formation method. The photoc~jtic reduction of CO2 was carried out in the presence of nanosized ZnS catalyst irradiated by a high-pressure mercury-vapor lamp to give the main products of formaldehyde and ethanol. The catalytic ability of ZnS characterized by the uptaken rate of CO2 volume in the reaction system depended upon the preparing conditions of nanosized ZnS catalysts. Decreasing the concentration of Na2 S and increasing the molar ratio of oxygen in the PVA to Zn2 + could result in the decreasing of the size of ZnS particles but could not result in the monotonous increasing of the reduction rate of CO2. The mechanism of reduction of CO2 may be related to the H atoms and OH radicals, which form from H2O by transmission of the electron-hole pairs from irradiated the naaosized ZnS.

  6. Risk of multiple interacting tipping points should encourage rapid CO2 emission reduction

    Science.gov (United States)

    Cai, Yongyang; Lenton, Timothy M.; Lontzek, Thomas S.

    2016-05-01

    Evidence suggests that several elements of the climate system could be tipped into a different state by global warming, causing irreversible economic damages. To address their policy implications, we incorporated five interacting climate tipping points into a stochastic-dynamic integrated assessment model, calibrating their likelihoods and interactions on results from an existing expert elicitation. Here we show that combining realistic assumptions about policymakers’ preferences under uncertainty, with the prospect of multiple future interacting climate tipping points, increases the present social cost of carbon in the model nearly eightfold from US$15 per tCO2 to US$116 per tCO2. Furthermore, passing some tipping points increases the likelihood of other tipping points occurring to such an extent that it abruptly increases the social cost of carbon. The corresponding optimal policy involves an immediate, massive effort to control CO2 emissions, which are stopped by mid-century, leading to climate stabilization at industrial levels.

  7. Direct reduction process using fines and with reduced CO2 emission

    CSIR Research Space (South Africa)

    Morrison, A

    2004-08-01

    Full Text Available ferroalloy CO2 emissions from 3.0 to 2.5 Mt/year. However, the cost of biocarbon is about double that of fossil fuel. The 1997 Kyoto Protocol requires signatories to reduce CO2 emissions to 7% below 1990 levels between 2008 and 2012 and methods.... 8. ‘Gmelin handbook’, Mn-C8, Compounds, 145–147; 1982. 9. BHP Billiton/Samancor Chrome, personal communication. 10. ‘Materials technology annual report’, Sintef, 1998 (www.sintef.no). 11. Kyoto Protocol, UNFCCC, Dec. 1997, Agenda Item 5. 12...

  8. NOx reduction using amine reclaimer wastes (ARW) generated in post combustion CO2 capture

    DEFF Research Database (Denmark)

    Botheju, Deshai; Glarborg, Peter; Tokheim, Lars-Andre

    2012-01-01

    Amine reclaimer wastes (ARW) generated in CO2 capture processes demand suitable disposal means. Such wastes contain remaining amine, NH3 and other degradation compounds. This study investigated the potential of using ARW as a NOx reducing agent, under laboratory conditions in a flow reactor....... A simulated flue gas containing about 500 ppm of NO and 5% O2 was injected with liquid ARW under different stoichiometric ratios (TN/NO – total N to nitric oxide ratio) and temperatures. The ARW was obtained from a distillation monoethanolamine reclaimer in an industrial CO2 capture facility with a coal fired...

  9. NiCo2O4 spinel/ordered mesoporous carbons as noble-metal free electrocatalysts for oxygen reduction reaction and the influence of structure of catalyst support on the electrochemical activity of NiCo2O4

    Science.gov (United States)

    Bo, Xiangjie; Zhang, Yufan; Li, Mian; Nsabimana, Anaclet; Guo, Liping

    2015-08-01

    Three ordered mesoporous carbons (OMCs) with different structures are used as catalyst supports for growth of NiCo2O4 spinel. The high surface area of OMCs provides more active sites to adsorb metal precursors. The porous structure confines the growth of NiCo2O4 and supplies more efficient transport passage for reactant molecules to access the active sites. Due to the structural characteristics of OMCs and catalytic properties of NiCo2O4, NiCo2O4/OMCs composites are highly active, cheap, and selective noble metal-free electrocatalysts for the oxygen reduction reaction (ORR) in alkaline solution. The electrochemical activity of NiCo2O4 supported on three OMCs with different structures, surface areas, pore sizes, pore volumes, and defective sites is studied. NiCo2O4/OMCs composites may be further used as efficient and inexpensive noble metal-free ORR catalysts in alkaline solution.

  10. Influence of Operational Parameters on the Photocatalytic Activity of Powdered TiO2 for the Reduction of CO2

    Directory of Open Access Journals (Sweden)

    Oman Zuas

    2014-07-01

    Full Text Available In this report, the results from a study on the influence of operational parameters on TiO2 photocatalytic activity for CO2 reduction under an ultraviolet-visible (UV-vis illumination are presented. The results indicated that the TiO2 was found to be active for CO2 reduction with CH3OH as the major products, while other minor products (CO, CH4, and C2H4 were also detected. In addition, the formation of such reduction products was obviously influenced by the operational parameters. Under this study, the optimum operational parameters for CO2 reduction at 298 °K were determined to be: NaOH concentration 0.2 M, TiO2 dosage 2 g/L, volume of the reaction media 75 mL, the pressure of system 800 kPa. It was also found that the increase in UV-vis illumination time have increased the yield of product formation. A possible reaction pathway for the formation of the reduction products is also discussed.

  11. Tiny crystalline grain nanocrystal NiCo2O4/N-doped graphene composite for efficient oxygen reduction reaction

    Science.gov (United States)

    Wan, Li-li; Zang, Guo-long; Wang, Xin; Zhou, Le-an; Li, Tian; Zhou, Qi-xing

    2017-03-01

    Oxygen reduction reaction (ORR) plays an important role in green energy conversion, although catalysts are necessary for overcoming its sluggish kinetic. Herein, a nanocrystal NiCo2O4/N-doped graphene composite material showing high ORR electrocatalytic activity is prepared. The resulting NiCo2O4/N-doped graphene composite (NiCo2O4-NG/C) combines the advantages of both component materials and shows enhanced ORR electrocatalytic activity (i.e., more positive peak potential and half-wave potential compared with NiCo2O4) while having higher diffusion-limited current density values (-5.7 mA cm-2, 1600 rpm), better tolerance to methanol, and improved stability than 20 wt% Pt/C. NiCo2O4 anchored on N-doped graphene are demonstrated to be nanocrystal with tiny crystalline grain (diameter < 5 nm) and result in large surface area, thereby allowing more active sites to be exposed. Moreover, the potential exposure of high-index planes may be also responsible for the observed high activity of these materials.

  12. Climate Change Mitigation Pathways for Southeast Asia: CO2 Emissions Reduction Policies for the Energy and Transport Sectors

    Directory of Open Access Journals (Sweden)

    Lew Fulton

    2017-07-01

    Full Text Available As of June 2017, 150 countries have ratified the Paris Climate Agreement. This agreement calls for, among other things, strong reductions in CO2 emissions by 2030 and beyond. This paper reviews the Nationally Determined Contribution (NDCs plans of six Association of Southeast Asian Nations (ASEAN countries and compares their current and projected future CO2 levels across sectors, and their stated targets in the context of their economic and demographic situations. This comparison reveals wide variations in the types of targets, with the “ambition” level changing as the perspective changes from total CO2 to CO2/capita and per unit gross domestic product (GDP. We also review national plans as stated in NDCs and find that while there are many types of policies listed, few are quantified and no attempts are made to score individual or groups of policies for their likelihood in achieving stated targets. We conclude that more analysis is needed to better understand the possible impacts of current policies and plans on CO2 emissions, and whether current plans are adequate to hit targets. Considerations on better aligning targets are also provided.

  13. Accelerating CO2-Emission Reductions via Corporate Programmes; Analysis of an Existing Corporate Programme

    NARCIS (Netherlands)

    Manser, J.; Handgraaf, M.J.J.; Schubert, R.; Gsottbauer, E.; Cornielje, M.; Lede, E.

    2013-01-01

    This working paper analyzes and assesses the COYou2 Program of the company Swiss Re. This corporate program allows employees to claim subsidies for the realization of various activities reducing their energy consumption and CO2-emissions at home. Examples of such activities are the purchase of a hyb

  14. Accelerating CO2-Emission Reductions via Corporate Programmes; Analysis of an Existing Corporate Programme

    NARCIS (Netherlands)

    Manser, J.; Handgraaf, M.J.J.; Schubert, R.; Gsottbauer, E.; Cornielje, M.; Lede, E.

    2013-01-01

    This working paper analyzes and assesses the COYou2 Program of the company Swiss Re. This corporate program allows employees to claim subsidies for the realization of various activities reducing their energy consumption and CO2-emissions at home. Examples of such activities are the purchase of a

  15. Acoustic waves in transversely excited atmospheric CO2 laser discharges: effect on performance and reduction techniques

    CSIR Research Space (South Africa)

    von Bergmann, HM

    2008-08-01

    Full Text Available Results are presented on the influence of acoustic waves on the performance of high-repetition-rate TEA CO2 lasers. It is shown that acoustic waves generated inside the laser cavity lead to nonuniform discharges, resulting in a deterioration...

  16. Briefly Discussing the Discharge Reduction of CO2 and Its Recovery-Utilization%试论CO2的减排与回收利用

    Institute of Scientific and Technical Information of China (English)

    王祥光

    2008-01-01

    介绍了国内几种从工业燃料燃烧的排放气中回收CO2的工艺流程、技术参数和装置特点;分别论述了5种Co2回收利用技术:以焦炭为原料、CO:为气化剂制CO;以CO2、纯氧、焦炭为原料制CO;以CO2与烃催化转化制CO;以CO2和H:为原料生产甲醇或直接生产二甲醚.

  17. Highly efficient visible light photocatalytic reduction of CO2 to hydrocarbon fuels by Cu-nanoparticle decorated graphene oxide.

    Science.gov (United States)

    Shown, Indrajit; Hsu, Hsin-Cheng; Chang, Yu-Chung; Lin, Chang-Hui; Roy, Pradip Kumar; Ganguly, Abhijit; Wang, Chen-Hao; Chang, Jan-Kai; Wu, Chih-I; Chen, Li-Chyong; Chen, Kuei-Hsien

    2014-11-12

    The production of renewable solar fuel through CO2 photoreduction, namely artificial photosynthesis, has gained tremendous attention in recent times due to the limited availability of fossil-fuel resources and global climate change caused by rising anthropogenic CO2 in the atmosphere. In this study, graphene oxide (GO) decorated with copper nanoparticles (Cu-NPs), hereafter referred to as Cu/GO, has been used to enhance photocatalytic CO2 reduction under visible-light. A rapid one-pot microwave process was used to prepare the Cu/GO hybrids with various Cu contents. The attributes of metallic copper nanoparticles (∼4-5 nm in size) in the GO hybrid are shown to significantly enhance the photocatalytic activity of GO, primarily through the suppression of electron-hole pair recombination, further reduction of GO's bandgap, and modification of its work function. X-ray photoemission spectroscopy studies indicate a charge transfer from GO to Cu. A strong interaction is observed between the metal content of the Cu/GO hybrids and the rates of formation and selectivity of the products. A factor of greater than 60 times enhancement in CO2 to fuel catalytic efficiency has been demonstrated using Cu/GO-2 (10 wt % Cu) compared with that using pristine GO.

  18. Spatiotemporal variations in growing season exchanges of CO2, H2O,and sensible heat in agricultural fields of the Southern GreatPlains

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Marc L.; Billesbach, David P.; Berry, Joseph A.; Riley,William J.; Torn, Margaret S.

    2007-06-13

    Climate, vegetation cover, and management create fine-scaleheterogeneity in unirrigated agricultural regions, with important but notwell-quantified consequences for spatial and temporal variations insurface CO2, water, and heat fluxes. We measured eddy covariance fluxesin seven agricultural fields--comprising winter wheat, pasture, andsorghum--in the U.S. Southern Great Plains (SGP) during the 2001-2003growing seasons. Land-cover was the dominant source of variation insurface fluxes, with 50-100 percent differences between fields planted inwinter-spring versus fields planted in summer. Interannual variation wasdriven mainly by precipitation, which varied more than two-fold betweenyears. Peak aboveground biomass and growing-season net ecosystem exchange(NEE) of CO2 increased in rough proportion to precipitation. Based on apartitioning of gross fluxes with a regression model, ecosystemrespiration increased linearly with gross primary production, but with anoffset that increased near the time of seed production. Because theregression model was designed for well-watered periods, it successfullyretrieved NEE and ecosystem parameters during the peak growing season,and identified periods of moisture limitation during the summer. Insummary, the effects of crop type, land management, and water limitationon carbon, water, and energy fluxes were large. Capturing the controllingfactors in landscape scale models will be necessary to estimate theecological feedbacks to climate and other environmental impactsassociated with changing human needs for agricultural production of food,fiber, and energy.

  19. Promotional effect of surface hydroxyls on electrochemical reduction of CO2 over SnOx/Sn electrode

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Chaonan; Han, Jinyu; Zhu, Xinli; Liu, Xiao; Wang, Hua; Mei, Donghai; Ge, Qingfeng

    2016-11-01

    Tin oxide (SnOx) formation on tin-based electrode surfaces during CO2 electrochemical reduction can have a significant impact on the activity and selectivity of the reaction. In the present study, density functional theory (DFT) calculations have been performed to understand the role of SnOx in CO2 reduction using a SnO monolayer on the Sn(112) surface as a model for SnOx. Water molecules have been treated explicitly and considered actively participating in the reaction. The results showed that H2O dissociates on the perfect SnO monolayer into two hydroxyl groups symmetrically on the surface. CO2 energetically prefers to react with the hydroxyl, forming a bicarbonate (HCO3(t)*) intermediate, which can then be reduced to either formate (HCOO*) by hydrogenating the carbon atom or carboxyl (COOH*) by protonating the oxygen atom. Both steps involve a simultaneous C-O bond breaking. Further reduction of HCOO* species leads to the formation of formic acid in the acidic solution at pH < 4, while the COOH* will decompose to CO and H2O via protonation. Whereas the oxygen vacancy (VO) in the monolayer maybe formed by the reduction of the monolayer, it can be recovered by H2O dissociation, resulting in two embedded hydroxyl groups. However, the hydroxylated surface with two symmetric hydroxyls is energetically more favorable for CO2 reduction than the hydroxylated VO surface with two embedded hydroxyls. The reduction potential for the former has a limiting-potential of -0.20 V (RHE), lower than that for the latter (-0.74 V (RHE)). Compared to the pure Sn electrode, the formation of SnOx monolayer on the electrode under the operating conditions promotes CO2 reduction more effectively by forming surface hydroxyls, thereby, providing a new channel via COOH* to the CO formation, although formic acid is still the major reduction product. The work was supported in part by National Natural Sciences Foundation of China (Grant #21373148 and #21206117). The High Performance Computing

  20. Charcoal injection in blast furnaces (Bio-PCI: CO2 reduction potential and economic prospects

    Directory of Open Access Journals (Sweden)

    Cristobal Feliciano-Bruzual

    2014-07-01

    Full Text Available The steel industry is under pressure to reduce its CO2 emissions, which arise from the use of coal. In the long-term, the injection of pulverized particles of charcoal from biomass through blast furnace tuyeres, in this case called Bio-PCI, is an attractive method from both an environmental and metallurgical viewpoint. The potential of Bio-PCI has been assessed in terms of its CO2 abatement potential and economic viewpoint. A cost objective function has been used to measure the impact of biochar substitution in highly fuel-efficient BF among the top nine hot metal producers; estimations are based on the relevant cost determinants of ironmaking. This contribution aims to shed light on two strategic questions: Under what conditions is the implementation of Bio-PCI economically attractive? Additionally, where is such a techno-economic innovation likely to be taken up the earliest? The results indicate the potential for an 18–40% mitigation of CO2. Findings from the economic assessment show that biochar cannot compete with fossil coal on price alone; therefore, a lower cost of biochar or the introduction of carbon taxes will be necessary to increase the competitiveness of Bio-PCI. Based on the current prices of raw materials, electricity and carbon taxes, biochar should be between 130.1 and 236.4 USD/t and carbon taxes should be between 47.1 and 198.7 USD/t CO2 to facilitate the substitution of Bio-PCI in the examined countries. In regard to implementation, Brazil, followed by India, China and the USA appeared to be in a better position to deploy Bio-PCI.

  1. U.S. onroad transportation CO2 emissions analysis comparing highly resolved CO2 emissions and a national average approach : mitigation options and uncertainty reductions

    Science.gov (United States)

    Mendoza, D. L.; Gurney, K. R.

    2011-12-01

    The transportation sector is the second largest CO2 emitting economic sector in the United States, accounting for 32.3% of the total U.S. emissions in 2002. Within the transportation sector, the largest component (80%) is made up of onroad emissions. In order to accurately quantify future emissions and evaluate emissions regulation strategies, analysis must account for spatially-explicit fleet distribution, driving patterns, and mitigation strategies. Studies to date, however, have either focused on one of these three components, have been only completed at the national scale, or have not explicitly represented CO2 emissions instead relying on the use of vehicle miles traveled (VMT) as an emissions proxy. We compare a high resolution onroad emissions data product (Vulcan) to a national averaging of the Vulcan result. This comparison is performed in four groupings: light duty (LD) and heavy duty (HD) vehicle classes, and rural and urban road classes. Two different bias metrics are studied: 1) the state-specific, group-specific bias and 2) the same bias when weighted by the state share of the national group-specific emissions. In the first metric, we find a spread of positive and negative biases for the LD and HD vehicle groupings and these biases are driven by states having a greater/lesser proportion of LD/HD vehicles within their total state fleet than found from a national average. The standard deviation of these biases is 2.01% and 0.75% for the LD and HD groupings, respectively. These biases correlate with the road type present in a state, so that biases found in the urban and LD groups are both positive or both negative, with a similar relationship found between biases of the rural and HD groups. Additionally, the road group bias is driven by the distribution of VMT on individual road classes within the road groupings. When normalized by national totals, the state-level group-specific biases reflect states with large amounts of onroad travel that deviate

  2. Band gap engineered, oxygen-rich TiO2 for visible light induced photocatalytic reduction of CO2.

    Science.gov (United States)

    Tan, Lling-Lling; Ong, Wee-Jun; Chai, Siang-Piao; Mohamed, Abdul Rahman

    2014-07-04

    A facile and dopant-free strategy was employed to fabricate oxygen-rich TiO2 (O2-TiO2) with enhanced visible light photoactivity. Such properties were achieved by the in situ generation of oxygen through the thermal decomposition of the peroxo-titania complex. The O2-TiO2 photocatalyst exhibited high photoactivity towards CO2 reduction under visible light.

  3. Evaluation of partial clinker replacement by sugar cane bagasse ash: CO2 emission reductions and potential for carbon credits

    OpenAIRE

    E. M. R. Fairbairn; De Paula,T. P.; G. C. Cordeiro; Americano,B. B.; Toledo Filho,R. D.

    2012-01-01

    This work presents a study about the viability of possible CO2 emissions reductions scenarios for the cement manufacturing through the implementation of Clean Development Mechanisms (CDM) associated with the partial replacement of cement by sugar cane bagasse ash (SCBA). Studies on the thermal, chemical and mechanical behavior of concretes containing 5 to 20% of ash indicated that there is improvement on the performance of all analyzed properties and that the ash can be used as admixture on t...

  4. Regional CO2 and latent heat surface fluxes in the Southern Great Plains: Measurements, modeling, and scaling

    Energy Technology Data Exchange (ETDEWEB)

    Riley, W. J.; Biraud, S.C.; Torn, M.S.; Fischer, M.L.; Billesbach, D.P.; Berry, J.A.

    2009-08-15

    Characterizing net ecosystem exchanges (NEE) of CO{sub 2} and sensible and latent heat fluxes in heterogeneous landscapes is difficult, yet critical given expected changes in climate and land use. We report here a measurement and modeling study designed to improve our understanding of surface to atmosphere gas exchanges under very heterogeneous land cover in the mostly agricultural U.S. Southern Great Plains (SGP). We combined three years of site-level, eddy covariance measurements in several of the dominant land cover types with regional-scale climate data from the distributed Mesonet stations and Next Generation Weather Radar precipitation measurements to calibrate a land surface model of trace gas and energy exchanges (isotope-enabled land surface model (ISOLSM)). Yearly variations in vegetation cover distributions were estimated from Moderate Resolution Imaging Spectroradiometer normalized difference vegetation index and compared to regional and subregional vegetation cover type estimates from the U.S. Department of Agriculture census. We first applied ISOLSM at a 250 m spatial scale to account for vegetation cover type and leaf area variations that occur on hundred meter scales. Because of computational constraints, we developed a subsampling scheme within 10 km 'macrocells' to perform these high-resolution simulations. We estimate that the Atmospheric Radiation Measurement Climate Research Facility SGP region net CO{sub 2} exchange with the local atmosphere was -240, -340, and -270 gC m{sup -2} yr{sup -1} (positive toward the atmosphere) in 2003, 2004, and 2005, respectively, with large seasonal variations. We also performed simulations using two scaling approaches at resolutions of 10, 30, 60, and 90 km. The scaling approach applied in current land surface models led to regional NEE biases of up to 50 and 20% in weekly and annual estimates, respectively. An important factor in causing these biases was the complex leaf area index (LAI) distribution

  5. Applicability of CDM to civil engineering projects case study on reduction of CO2 emission by port extension

    Energy Technology Data Exchange (ETDEWEB)

    Sekimoto, T. [Penta-Ocean Construction Co. LTD, Yonku-cho 1534-1, Nishinasuno-machi, Nasu, Tochigi, 329-2746 (Japan)

    2003-07-01

    This paper investigates the applicability of CDM to civil engineering projects through a case study on the project to extend Port Samainda in Indonesia. The goal of this project is to improve the physical distribution system of the port so that it can accommodate increasing future demand for the cargo transportation. Based on the project report by JICA (2002), we first outline the predicted demand for the cargo transportation and select possible three options in which a cargo vessel with different capabilities and respective port facilities are assigned. For each option, CO2 emissions from both cargo and dredging vessels are predicted and compared. It is found that the total CO2 emission may be reduced significantly by introducing a large-draft vessel and deep navigation channels. This feature becomes more prominent if a traveling distance of the cargo vessels is long enough so that CO2 emissions from cargo vessels dominates those of dredging vessels. This observation supports the applicability of CDM to civil engineering projects because reduction of the CO2 emission is attained by improving distribution systems through civil engineering works such as extension of the port and the maintenance dredging. Finally, we discuss future problems to be investigated for the practical application of CDM to a civil engineering project.

  6. Reduction of transpiration and altered nutrient allocation contribute to nutrient decline of crops grown in elevated CO(2) concentrations.

    Science.gov (United States)

    McGrath, Justin M; Lobell, David B

    2013-03-01

    Plants grown in elevated [CO(2) ] have lower protein and mineral concentrations compared with plants grown in ambient [CO(2) ]. Dilution by enhanced production of carbohydrates is a likely cause, but it cannot explain all of the reductions. Two proposed, but untested, hypotheses are that (1) reduced canopy transpiration reduces mass flow of nutrients to the roots thus reducing nutrient uptake and (2) changes in metabolite or enzyme concentrations caused by physiological changes alter requirements for minerals as protein cofactors or in other organic complexes, shifting allocation between tissues and possibly altering uptake. Here, we use the meta-analysis of previous studies in crops to test these hypotheses. Nutrients acquired mostly by mass flow were decreased significantly more by elevated [CO(2) ] than nutrients acquired by diffusion to the roots through the soil, supporting the first hypothesis. Similarly, Mg showed large concentration declines in leaves and wheat stems, but smaller decreases in other tissues. Because chlorophyll requires a large fraction of total plant Mg, and chlorophyll concentration is reduced by growth in elevated [CO(2) ], this supports the second hypothesis. Understanding these mechanisms may guide efforts to improve nutrient content, and allow modeling of nutrient changes and health impacts under future climate change scenarios.

  7. Uncertainty-averse TRANSCO planning for accommodating renewable energy in CO2 reduction environment

    DEFF Research Database (Denmark)

    Zhang, Chunyu; Ding, Yi; Wang, Qi

    2015-01-01

    strategic planning to handle the uncertainty challenges from the intermittent renewable energy resources. In this paper, a stochastic multi-period multi-objective transmission planning (MPMOTP) model is proposed to reduce correlated uncertainties from renewable energy generation, conventional generation......The concern of the environment and energy sustainability requests a crucial target of CO2 abatement and results in a relatively high penetration of renewable energy generation in the transmission system. For maintaining system reliability and security, the transmission company (TRANSCO) has to make...

  8. Electrochemical reduction of CO2 and H2O into fuels: Cell types and kinetic barriers

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg

    2013-01-01

    of production rate/cost. Production rate is determined mainly by electrode kinetics. Therefore, parallel to improving the electrodes of these electrolyser cells, other cell types, which have faster electrode kinetics, can electrolyse CO2 and have potential lower investment costs, are being researched......), and may be operated above 800 °C. A short review of the various types is presented, and the limitations of the kinetics are described. The pros and cons of high temperature and pressure as measures to increase the electrode kinetics are discussed. Naturally, the reaction rates increase with temperature...

  9. Energy Conservation and CO2 Emission Reduction Using Cogeneration Based on Gas Microturbine

    Directory of Open Access Journals (Sweden)

    Arezoo Khalili

    2013-09-01

    Full Text Available Daily increasing propagation of environmental pollutants, such as CO2 as the most prevailing greenhouse gas, has resulted in global warming and climate changes in the past decades. Therefore, essentiality of the optimum utilization of limited sources of energy which in turn leads to emission abatement in energy conversion process is being widely under consideration. Cogeneration, regarding energy conservation and efficiency enhancement, is known to be a noticeable and overriding strategy in substantiation of energy consumption management goal. This study deals with performance evaluation of a microturbine-based cogeneration plant and its effects on efficiency and environmental aspects by using a simulator code.

  10. CO2在Au25团簇修饰玻碳电极上的电催化还原%The electrochemical reduction of CO2 on Au25 modified electrode

    Institute of Scientific and Technical Information of China (English)

    李伟; 金葆康

    2015-01-01

    Au25 modified glassy carbon electrode (GCE) was prepared and characterized by AC impedance .Cyclic voltammetry and IR spectroelectrochemistry were utilized to investigate the electrochemical reaction process of CO2 at GCE and Au25 modified GCE . The experimental results suggested that Au25 modified electrode had effective catalytic activity in the electrochemical reduction of CO2 .Au25 could reduce the overpotential in the reduction of CO2 .Finally ,the mechanism of electrochemical reduction of CO2 is studied at GCE and Au25 modified GCE .%制备A u25团簇修饰玻碳电极,利用电化学阻抗对其进行表征。通过循环伏安法与红外光谱电化学法,分别研究CO2在玻碳电极与Au25团簇修饰玻碳电极上的电化学还原过程,分析CO2还原过程在两者上的差异。电化学和现场红外差谱结果表明:Au25团簇修饰电极对CO2具有良好的电催化还原活性,降低了CO2电化学还原过电位,探讨了CO2在Au25团簇修饰玻碳电极的电化学还原的反应机制。

  11. Theoretic Insight into CO2 Reduction at Active Sites of Molybdenum and Tungsten Enzymes: a {\\pi} Interaction between CO2 and Tungsten Bis-Dithiolene Complexes

    CERN Document Server

    Yan, Yong

    2014-01-01

    Active sites of molybdenum and tungsten enzymes, particularly mononuclear tungsten formate dehydrogenase (FDH) have been theoretically investigated towards their interaction with CO2. Obvious {\\pi} interaction has been found between the 2e reduced metallodithiole moiety and the molecular CO2. This weak {\\pi} bonding is predicated both at gas phase, noted as -6.0 kcal/mol and aqueous solvation level, -3.6 kcal/mol. Such interaction is not only limited to CO2, but also to the CO2 reduced product, i.e. formate, in the form of anion- {\\pi} interaction, noted as -6.8 kcal/mol and -4.1 kcal/mol respectively in gas and aqueous solvation model. The Bailar twisted angles from 60o to 0o, governing structure preference of tungsten dithiolene from octahedron to triangle prism in their restricted structures, has been explored to evaluate such {\\pi} in-terrelations with CO2 and formate. An octahedral structure with 3 kcal/mol energy lower is preferred over the triangle prismatic when such interactions are concerned.

  12. Progress of the electrochemical reduction of CO2 in aqueous electrolyte%水溶液中电化学还原CO2的研究进展

    Institute of Scientific and Technical Information of China (English)

    张现萍; 黄海燕; 靳红利; 俞英; 陈英敦

    2015-01-01

    CO2作为一种潜在的碳资源,寻找一种有效的方法转移利用 CO2一直是社会关注的焦点.水溶液中电化学方法转化固定 CO2可在室温和常压下进行,通过选择不同电极和电极电势来改变产物、调控反应速率和选择性,因而具有潜在的优势.本文综述了水溶液中电化学还原 CO2的发展现状,介绍了水溶液中电还原 CO2的基本原理和电极上发生的主要反应;总结了水溶液中金属电极、气体扩散电极(GDEs)和复合电极等不同电极材料对 CO2还原产物的种类、选择性以及电流效率的影响;讨论了温度、CO2分压等还原反应条件对反应速率和电流效率的影响.展望了水溶液中电还原CO2技术的发展前景,认为利用水基溶液中丰富的[H],增强CO2还原产物的燃料化程度,将在环境保护、资源利用和经济效益方面具有极大价值,符合绿色化学发展理念.%AsCO2 is a vital reagent for the production of useful chemicals,it is high time to find an efficient way to make use of it. The electrochemical reduction of CO2,which can be conducted under the ambient conditions and converse CO2 into various products,provides a promising future both for the utilization of CO2 and for the human beings. The products,the reaction rate and the selectivity of the reaction can be adjusted by conducting the reaction on different electrodes and at different over potentials. This paper highlights the progress of the electrochemical reduction of CO2 in aqueous electrolyte and summarizes the mechanism of electrochemical reduction of CO2 proposed by various workers and introduces the main reactions occurred during the reduction process. Studies carried out on different kinds of electrodes,such as metal electrodes,gas diffusion electrodes (GDEs) and composite electrodes and so on,have also been reviewed. The products,the selectivity of the reaction and the currency during the process of reduction,also vary with the materials

  13. Photocatalytic reduction of CO2 by CuxO nanocluster loaded SrTiO3 nanorod thin film

    Science.gov (United States)

    Shoji, Shusaku; Yin, Ge; Nishikawa, Masami; Atarashi, Daiki; Sakai, Etsuo; Miyauchi, Masahiro

    2016-08-01

    Photocatalytic carbon dioxide (CO2) conversion into carbon monoxide (CO) using H2O as an electron donor was achieved by the strontium titanate (SrTiO3: STO) nanorod thin films loaded with amorphous copper oxide (CuxO) nanoclusters. The loading of the CuxO-cocatalysts onto STO nanorods clearly improved the photocatalytic activity compared to bare STO nanorods. The CuxO-cocatalysts are composed of abundant and non-toxic elements, and can be loaded by using a simple and economical method. Our findings demonstrate that CuxO nanoclusters function as a general cocatalyst and can be used in combination with various semiconductors to construct low-cost and efficient photocatalytic CO2 reduction systems.

  14. Assessment of Energy Efficiency Improvement and CO2 Emission Reduction Potentials in India's Iron and Steel Industry

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, III, William R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hasanbeigi, Ali [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sathaye, Jayant [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Xu, Tengfang [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-12-03

    India’s 2010 annual crude steel production was 68 Mt which accounted for nearly five percent of the world’s annual steel production in the same year. In 2007, roughly 1600 PJ were consumed by India’s iron and steel industry to produce 53 Mt of steel. We identified and analyzed 25 energy efficiency technologies and measures applicable to the processes in the Indian iron and steel industry. The Conservation Supply Curve (CSC) used in this study is an analytical tool that captures both the engineering and the economic perspectives of energy conservation. Using a bottom-up electricity CSC model and compared to an electricity price forecast the cumulative plant-level cost-effective electricity savings potential for the Indian iron and steel industry for 2010-2030 is estimated to be 66 TWh, and the cumulative plant-level technical electricity saving potential is only slightly greater than 66 TWh for the same period. The primary energy related CO2 emissions reduction associated with cost-effective electricity savings is 65 Mt CO2. Compared to a fuel price forecast, an estimated cumulative cost-effective fuel savings potential of 768 PJ with associated CO2 emission reduction of 67 Mt CO2 during 2010-2030 is possible. In addition, a sensitivity analysis with respect to the discount rate used is conducted to assess the effect of changes in this parameter on the results. The result of this study gives a comprehensive and easy to understand perspective to the Indian iron and steel industry and policy makers about the energy efficiency potential and its associated cost.

  15. Can a reduction of solar irradiance counteract CO2-induced climate change? – Results from four Earth system models

    Directory of Open Access Journals (Sweden)

    M. Lawrence

    2012-01-01

    Full Text Available In this study we compare the response of four state-of-the-art Earth system models to climate engineering under scenario G1 of the GeoMIP and IMPLICC model intercomparison projects. In G1, the radiative forcing from an instantaneous quadrupling of the CO2 concentration, starting from the preindustrial level, is balanced by a reduction of the solar constant. Model responses to the two counteracting forcings in G1 are compared to the preindustrial climate in terms of global means and regional patterns and their robustness. While the global mean surface air temperature in G1 remains almost unchanged, the meridional temperature gradient is reduced in all models compared to the control simulation. Another robust response is the global reduction of precipitation with strong effects in particular over North and South America and northern Eurasia. It is shown that this reduction is only partly compensated by a reduction in evaporation so that large continental regions are drier in the engineered climate. In comparison to the climate response to a quadrupling of CO2 alone the temperature responses are small in experiment G1. Precipitation responses are, however, of comparable magnitude but in many regions of opposite sign.

  16. Reduction mechanism of high-chromium vanadium-titanium magnetite pellets by H2-CO-CO2 gas mixtures

    Science.gov (United States)

    Tang, Jue; Chu, Man-sheng; Li, Feng; Tang, Ya-ting; Liu, Zheng-gen; Xue, Xiang-xin

    2015-06-01

    The reduction of high-chromium vanadium-titanium magnetite as a typical titanomagnetite containing 0.95wt% V2O5 and 0.61wt% Cr2O3 by H2-CO-CO2 gas mixtures was investigated from 1223 to 1373 K. Both the reduction degree and reduction rate increase with increasing temperature and increasing hydrogen content. At a temperature of 1373 K, an H2/CO ratio of 5/2 by volume, and a reduction time of 40 min, the degree of reduction reaches 95%. The phase transformation during reduction is hypothesized to proceed as follows: Fe2O3 → Fe3O4 → FeO → Fe; Fe9TiO15 + Fe2Ti3O9 → Fe2.75Ti0.25O4 → FeTiO3 → TiO2; (Cr0.15V0.85)2O3 → Fe2VO4; and Cr1.3Fe0.7O3 → FeCr2O4. The reduction is controlled by the mixed internal diffusion and interfacial reaction at the initial stage; however, the interfacial reaction is dominant. As the reduction proceeds, the internal diffusion becomes the controlling step.

  17. Development and Choice of Carbon Dioxide Reduction Technology in Manned Spaceflight%载人航天CO2还原技术的发展与选择

    Institute of Scientific and Technical Information of China (English)

    史乔升; 杨春信

    2014-01-01

    CO2还原是目前国际空间站CO2处理的一个重要环节.CO2还原技术不仅可以实现对人体代谢产生的CO2进行处理,还可以与电解水技术结合起来实现氧气的再生.空间站所采用的CO2还原技术包括Sabatier、Bosch、CO2电解、CO2热解等还原方法.经过三十多年的理论与实验研究,最终Sabatier还原法被确定为国际空间站的CO2还原方案.然而,Sabatier方法的循环闭合度较低,难以应用在宇宙深空探测等更长期的载人航天任务中.其他可实现完全闭合的还原法仍有可能在技术充分发展后,取代Sabatier成为性能更优的还原技术.%CO2 reduction is an important part of the international space station CO2 treatment.CO2 reduction technology can not only remove the CO2 generated by human metabolism process,but also be combined with electrolyzed water technology together to achieve oxygen regeneration.CO2 reduction technology used in space station includes Sabatier,Bosch,CO2 electrolysis and CO2 pyrolysis.After thirty years of theoretical and experimental research,Sabatier reduction was ultimately identified as the CO2 reduction method in the International Space Station.However,because of its low closure,Sabatier method is difficult to be applied in even longer manned space missions such as the deep space exploration.Other methods that can accomplish complete close reduction may take the place of Sabatier method after their maturity and become superior reduction technologies.

  18. 沼液培养的普通小球藻对CO2的去除%Reduction of CO2 by Chlorella vulgaris Cultured in Biogas Slurry

    Institute of Scientific and Technical Information of China (English)

    王钦琪; 李环; 王翠; 韦萍

    2011-01-01

    The use of microalgae for CO2 fixation and wastewater treatment has been one of the most important research fields of microalgal utilization. In this study, Chlorella vulgaris was cultivated in nutritious effluent from methane zymolysis, and after domestication, C. Vulgaris grew well in different concentrations of biogas slurry. C. Vulgaris had excellent growth and tolerance to high concentrations of CO2, and the largest biomass productivity was obtained at the aeration of 1.5% CO2. Therefore, the CO2 reduction by C. Vulgaris in biogas slurry was investigated. The results showed that increasing the growth rate of C. Vulgaris and CO2 concentration could enhance the amount of CO2 reduction by C. Vulgaris, and reducing the aeration also improved the removal efficiency of CO2 The CO2 removal efficiency reached 30.61% when the cultures were aerated with 1.5% CO2 at a rate of 60 mL min-1. Furthermore, When the cultures were aerated with 10% CO2 at a rate of 100 mL min-1, the maximum reduction amount of CO2 was 279.7 mg L-1 h-1. A six series-wound photobioreactor was used to reduce CO2 in crude biogas by C. Vulgaris. The results revealed that the reduction amount of CO2 was similar in the single photobioreactor and in the six series-wound photobioreactor [(205.80 ± 13.20) mg L-1 h-1]. But the reduction rate in the latter was 60.32% ± 3.73%, about six times higher than that in the former. The above results indicated that C. Vulgaris had a remarkable removal effect on the CO2 in biogas. Fig 4, Tab 2, Ref 17%利用微藻同定CO2和处理污水已成为微藻应用的一个重要研究方向.利用营养丰富的沼气发酵废液培养小球藻,藻种经驯化后在不同浓度沼液中能良好生长.小球藻在高浓度的CO2中有较好的生长和较强的耐受能力,在l.5%CO2通气下生物量最高.在此基础上考察了沼液中小球藻对CO2的去除情况.结果表明,提高小球藻生长速率和CO2浓度可以增加小球藻对CO2的去除量,降低通气也可提高CO

  19. Novel windows for "solar commodities": a device for CO2 reduction using plasmonic catalyst activation.

    Science.gov (United States)

    Navarrete, Alexander; Muñoz, Sergio; Sanz-Moral, Luis M; Brandner, Juergen J; Pfeifer, Peter; Martín, Ángel; Dittmeyer, Roland; Cocero, María J

    2015-01-01

    A novel plasmonic reactor concept is proposed and tested to work as a visible energy harvesting device while allowing reactions to transform CO2 to be carried out. Particularly the reverse water gas shift (RWGS) reaction has been tested as a means to introduce renewable energy into the economy. The development of the new reactor concept involved the synthesis of a new composite capable of plasmonic activation with light, the development of an impregnation method to create a single catalyst reactor entity, and finally the assembly of a reaction system to test the reaction. The composite developed was based on a Cu/ZnO catalyst dispersed into transparent aerogels. This allows efficient light transmission and a high surface area for the catalyst. An effective yet simple impregnation method was developed that allowed introduction of the composites into glass microchannels. The activation of the reaction was made using LEDs that covered all the sides of the reactor allowing a high power delivery. The results of the reaction show a stable process capable of low temperature transformations.

  20. Simultaneous studies on solar energy storage by CO2 reduction to HCOOH with Brilliant Green dye removal photoelectrochemically

    Directory of Open Access Journals (Sweden)

    V.S.K. Yadav

    2016-12-01

    Full Text Available The simultaneous study on photoelectrochemical CO2 reduction with Brilliant Green (BG dye removal was studied in the present work. Experimental studies were done in aqueous solutions of sodium and potassium based electrolytes using a cathode [Zinc (Zn and Tin (Sn] and a common cobalt oxide (Co3O4 anode electrocatalyst. The influence of reaction with electrolyte concentration for the both catalysts was shown clearly with respect to time. The selected electrocatalysts were able to reduce CO2 to formic acid (HCOOH along with high BG dye removal. With Sn as cathode, the maximum BG dye removal was obtained to be KHCO3–[95.9% (10 min–0.2 M], NaHCO3–[98.6% (15 min–0.6 M]. Similarly for Zn, KHCO3–[99.8% (10 min–0.4 M], NaHCO3–[99.9% (20 min–0.8 M] were observed respectively. Finally, the results have proven that higher efficiencies for BG dye removal were obtained along with HCOOH formation, which might be a better alternate for water purification and to decrease the atmospheric CO2 concentrations.

  1. Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 1. Sulfate from confining beds as an oxidant in microbial CO2 production

    Science.gov (United States)

    Chapelle, F.H.; McMahon, P.B.

    1991-01-01

    A primary source of dissolved inorganic carbon (DIC) in the Black Creek aquifer of South Carolina is carbon dioxide produced by microbially mediated oxidation of sedimentary organic matter. Groundwater chemistry data indicate, however, that the available mass of inorganic electron acceptors (oxygen, Fe(III), and sulfate) and observed methane production is inadequate to account for observed CO2 production. Although sulfate concentrations are low (approximately 0.05-0.10 mM) in aquifer water throughout the flow system, sulfate concentrations are greater in confining-bed pore water (0.4-20 mM). The distribution of culturable sulfate-reducing bacteria in these sediments suggests that this concentration gradient is maintained by greater sulfate-reducing activity in sands than in clays. Calculations based on Fick's Law indicate that possible rates of sulfate diffusion to aquifer sediments are sufficient to explain observed rates of CO2 production (about 10-5 mmoll-1 year-1), thus eliminating the apparent electron-acceptor deficit. Furthermore, concentrations of dissolved hydrogen in aquifer water are in the range characteristic of sulfate reduction (2-6 nM), which provides independent evidence that sulfate reduction is the predominant terminal electron-accepting process in this system. The observed accumulation of pyrite- and calcite-cemented sandstones at sand-clay interfaces is direct physical evidence that these processes have been continuing over the history of these sediments. ?? 1991.

  2. Technology priorities for transport in Asia: assessment of economy-wide CO2 emissions reduction for Lebanon

    DEFF Research Database (Denmark)

    Dhar, Subash; Marpaung, Charles O. P.

    2015-01-01

    This paper analyses the technology choices of countries that prioritized transport as a sector in Asia under the Technology Needs Assessment project. The countries used a wide variety of criteria to prioritize technologies which were related to the benefits technologies would provide, costs...... mitigations actions (NAMA) given their strong contribution for development and therefore a methodology based on in-put out-put decomposition analysis is proposed for analysing economy wide CO2 emissions reductions. The methodology has been applied for the transport sector of Lebanon where alternative fuels...

  3. Manganese Tricarbonyl Complexes with Asymmetric 2-Iminopyridine Ligands: Toward Decoupling Steric and Electronic Factors in Electrocatalytic CO2 Reduction.

    Science.gov (United States)

    Spall, Steven J P; Keane, Theo; Tory, Joanne; Cocker, Dean C; Adams, Harry; Fowler, Hannah; Meijer, Anthony J H M; Hartl, František; Weinstein, Julia A

    2016-12-19

    Manganese tricarbonyl bromide complexes incorporating IP (2-(phenylimino)pyridine) derivatives, [MnBr(CO)3(IP)], are demonstrated as a new group of catalysts for CO2 reduction, which represent the first example of utilization of (phenylimino)pyridine ligands on manganese centers for this purpose. The key feature is the asymmetric structure of the redox-noninnocent ligand that permits independent tuning of its steric and electronic properties. The α-diimine ligands and five new Mn(I) compounds have been synthesized, isolated in high yields, and fully characterized, including X-ray crystallography. Their electrochemical and electrocatalytic behavior was investigated using cyclic voltammetry and UV-vis-IR spectroelectrochemistry within an OTTLE cell. Mechanistic investigations under an inert atmosphere have revealed differences in the nature of the reduction products as a function of steric bulk of the ligand. The direct ECE (electrochemical-chemical-electrochemical) formation of a five-coordinate anion [Mn(CO)3(IP)](-), a product of two-electron reduction of the parent complex, is observed in the case of the bulky DIPIMP (2-[((2,6-diisopropylphenyl)imino)methyl]pyridine), TBIMP (2-[((2-tert-butylphenyl)imino)methyl]pyridine), and TBIEP (2-[((2-tert-butylphenyl)imino)ethyl]pyridine) derivatives. This process is replaced for the least sterically demanding IP ligand in [MnBr(CO)3(IMP)] (2-[(phenylimino)methyl]pyridine) by the stepwise formation of such a monoanion via an ECEC(E) mechanism involving also the intermediate Mn-Mn dimer [Mn(CO)3(IMP)]2. The complex [MnBr(CO)3(IPIMP)] (2-[((2-diisopropylphenyl)imino)methyl]pyridine), which carries a moderately electron donating, moderately bulky IP ligand, shows an intermediate behavior where both the five-coordinate anion and its dimeric precursor are jointly detected on the time scale of the spectroelectrochemical experiments. Under an atmosphere of CO2 the studied complexes, except for the DIPIMP derivative, rapidly

  4. Electrochemical reduction of CO2 by binuclear Co and Ni complexes

    NARCIS (Netherlands)

    Mackor, A.; Koster, T.P.M.; Collin, J.P.; Jouaiti, A.; Sauvage, J.P.

    1989-01-01

    Several bis(metal) complexes of biscyclam 2 (Me=Co,Ni) were prepared by Fabbrizzi’s method and they were electrochemically characterised, using a rotating ring-disk electrode. It was confirmed that these complexes have no special advantage for the electrocatalytic reduction of C02. A second class of

  5. Deep CO2 emission reductions in a global bottom-up model approach

    NARCIS (Netherlands)

    Deetman, Sebastiaan; Hof, Andries; van Vuuren, Detlef P.

    2015-01-01

    Most studies that explore deep GHG emission reduction scenarios assume that climate goals are reached by implementing least-cost emission mitigation options, typically by implementing a global carbon tax. Although such a method provides insight into total mitigation costs, it does not provide much i

  6. Chemical Reduction of CO2 to Different Products during Photo Catalytic Reaction on TiO2 under Diverse Conditions: an Overview

    Institute of Scientific and Technical Information of China (English)

    G.R.Dey

    2007-01-01

    The chemical reduction of CO2 remains a challenge with respect to the reversal of the oxidative degradation of any organic materials.The conversion of CO2 into useful substances is essential in developing alternative fuels and various raw materials for different industries.This also aids in preventing the continuous rise in tropospheric temperature due to the green house effect of CO2.In this article an overview of the growth taken place so far in the field of CO2 chemical reduction is presented.The discussion comprises of photochemical methods for the development of different products,viz.CO,CH3OH and CH4,through chemical reduction of CO2.This includes the use of photo catalysts,mainly TiO2,and the role of a hole scavenger(such as 2-propan01) for this purpose.

  7. Biological/biomedical accelerator mass spectrometry targets. 1. optimizing the CO2 reduction step using zinc dust.

    Science.gov (United States)

    Kim, Seung-Hyun; Kelly, Peter B; Clifford, Andrew J

    2008-10-15

    Biological and biomedical applications of accelerator mass spectrometry (AMS) use isotope ratio mass spectrometry to quantify minute amounts of long-lived radioisotopes such as (14)C. AMS target preparation involves first the oxidation of carbon (in sample of interest) to CO 2 and second the reduction of CO 2 to filamentous, fluffy, fuzzy, or firm graphite-like substances that coat a -400-mesh spherical iron powder (-400MSIP) catalyst. Until now, the quality of AMS targets has been variable; consequently, they often failed to produce robust ion currents that are required for reliable, accurate, precise, and high-throughput AMS for biological/biomedical applications. Therefore, we described our optimized method for reduction of CO 2 to high-quality uniform AMS targets whose morphology we visualized using scanning electron microscope pictures. Key features of our optimized method were to reduce CO 2 (from a sample of interest that provided 1 mg of C) using 100 +/- 1.3 mg of Zn dust, 5 +/- 0.4 mg of -400MSIP, and a reduction temperature of 500 degrees C for 3 h. The thermodynamics of our optimized method were more favorable for production of graphite-coated iron powders (GCIP) than those of previous methods. All AMS targets from our optimized method were of 100% GCIP, the graphitization yield exceeded 90%, and delta (13)C was -17.9 +/- 0.3 per thousand. The GCIP reliably produced strong (12)C (-) currents and accurate and precise F m values. The observed F m value for oxalic acid II NIST SRM deviated from its accepted F m value of 1.3407 by only 0.0003 +/- 0.0027 (mean +/- SE, n = 32), limit of detection of (14)C was 0.04 amol, and limit of quantification was 0.07 amol, and a skilled analyst can prepare as many as 270 AMS targets per day. More information on the physical (hardness/color), morphological (SEMs), and structural (FT-IR, Raman, XRD spectra) characteristics of our AMS targets that determine accurate, precise, and high-hroughput AMS measurement are in the

  8. Simulation and prediction of CO2 emission reductions of biogas industry in China%中国沼气产业对减排CO2的模拟与预测

    Institute of Scientific and Technical Information of China (English)

    杨艳丽; 李光全; 张培栋

    2013-01-01

      沼气是中国可再生能源建设的重点项目,可提供清洁能源替代化石燃料燃烧,减少温室气体排放,对缓解全球变暖趋势具有重要意义。该文利用复合回归模型对中国沼气行业的CO2减排量(CO2 ER)与生物质资源、农村用能结构以及沼气利用现状等指标之间的数值关系进行模拟分析,结果表明:中国户用沼气行业的CO2减排量与沼气池使用量存在显著的线性关系(R2=0.992),与户均产气量存在明显的S函数关系(R2=0.677),大中型沼气工程行业的CO2减排量与池容之间存在显著的线性关系(R2=0.977);经多元线性回归和曲线拟合所得到的复合回归模型对户用沼气行业 CO2减排量的拟合较好,各种替代情景下误差率均在5%以内;对大中型沼气工程行业CO2减排量的模拟在2006年后呈现较好的拟合效果,各种替代情景下误差率均在2%以内。依据《可再生能源发展‘十二五’规划》进行预测,2015年中国沼气行业可减少CO2排放6.18×107~1.38×108t。加强沼气科技研发,促使沼气工业化、规模化发展以及提升沼气利用品味,是保持沼气利用CO2减排重要地位的有效途径。%Biogas project is a key program to renewable energy construction in China. As a daily-consumed energy for livelihood, biogas can substitute traditional energy and provide clean energy for rural residents, which can reduce the emissions of greenhouse gases such as CO2, CH4, et al. The CO2 emissions by biogas utilization are always calculated by IPCC methods, while, the CO2 emissions reduction (CO2 ER) by biogas utilization should be calculated by many indexes, such as living energy structure, biogas development conditions, the calorific value, used way, converting efficiency and carbon emissions coefficient of biogas and substituted fuel. It is a complicated process with large amount of manpower and material resources consumed

  9. EAF Gas Waste Heat Utilization and Discussion of the Energy Conservation and CO2 Emissions Reduction

    Science.gov (United States)

    Yang, Ling-zhi; Zhu, Rong; Ma, Guo-hong

    2016-02-01

    As a large number of energy was taken away by the high temperature furnace gas during the EAF smelting process, a huge economic and environmental benefits would obtained to recycle and utilize. In this paper, the energy of the EAF was analyzed theoretically with the hot metal ratio of 50%. Combined with the utilization of the gas waste heat during the scrap preheating, electricity generation, production of steam and production of coal gas processes, the effect of the energy saving and emission was calculated with comprehensive utilization of the high temperature furnace gas. An optimal scheme for utilization of the waste heat was proposed based on the calculation. The results show that the best way for energy saving and carbon reduction is the production of coal gas, while the optimal scheme for waste heat utilization is combined the production of coal gas with the scrap preheating, which will save 170 kWh/t of energy and decrease 57.88 kg/t of carbon emission. As hot metal ratio in EAF steelmaking is often more than 50%, which will produce more EAF gas waste heat, optimizing EAF gas waste heat utilization will have more obvious effect on energy saving and emission reduction.

  10. Structure Effects on the Energetics of the Electrochemical Reduction of CO2 by Copper Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Durand, William

    2011-08-19

    Polycrystalline copper electrocatalysts have been experimentally shown to be capable of reducing CO{sub 2} into CH{sub 4} and C{sub 2}H{sub 4} with relatively high selectivity, and a mechanism has recently been proposed for this reduction on the fcc(211) surface of copper, which was assumed to be the most active facet. In the current work, we use computational methods to explore the effects of the nanostructure of the copper surface and compare the effects of the fcc(111), fcc(100) and fcc(211) facets of copper on the energetics of the electroreduction of CO{sub 2}. The calculations performed in this study generally show that the intermediates in CO{sub 2} reduction are most stabilized by the (211) facet, followed by the (100) facet, with the (111) surface binding the adsorbates most weakly. This leads to the prediction that the (211) facet is the most active surface among the three in producing CH{sub 4} from CO{sub 2}, as well as the by-products H{sub 2} and CO. HCOOH production may be mildly enhanced on the more close-packed surfaces ((111) and (100)) as compared to the (211) facet, due to a change in mechanism from a carboxyl intermediate to a formate intermediate. The results are compared to experimental data on these same surfaces; the predicted trends in voltage requirements are consistent between the experimental and computational data.

  11. Consequences of Market-Based Measures CO2-emission Reduction Maritime Transport for the Netherlands; Gevolgen Market Based Measures CO2-emissiereductie zeevaart voor Nederland

    Energy Technology Data Exchange (ETDEWEB)

    Wortelboer-van Donselaar, P.; Kansen, M.; Moorman, S. [Kennisinstituut voor Mobiliteitsbeleid KiM, Den Haag (Netherlands); Faber, J.; Koopman, M.; Smit, M. [CE Delft, Delft (Netherlands)

    2013-11-15

    The introduction of Market Based Measures (MBMs) to reduce the CO2 emissions of international sea shipping will have relatively limited economic effects for the Netherlands. Moreover, these effects are largely in line with those in other countries. For the Netherlands, however, the manner in which MBMS are organised and enforced is likely to be particularly important, given the importance of ports to the Dutch economy, the country's relatively large bunker sector, and the fact that Dutch shipowners operate relatively small vessels and on a relatively small scale. MBMs include pricing measures in the form of tax or trade systems, as well as other market-related proposals. In this research study, the consequences are analysed of four international MBM proposals for the Netherlands [Dutch] Om de CO2-uitstoot van de internationale zeevaartsector terug te dringen worden momenteel zogeheten Market Based Measures (MBMs), zoals bijvoorbeeld het veilen van emissierechten of het invoeren van een heffing, overwogen. De invoering van de MBMs zal voor Nederland relatief beperkte economische effecten hebben. Deze effecten wijken bovendien niet bijzonder af van die voor andere landen. De wijze waarop de MBMs worden georganiseerd en gehandhaafd, is voor Nederland mogelijk wel van onderscheidend belang. Dit gezien het belang van de havens voor de Nederlandse economie, de relatief grote bunkersector, en de relatief kleine schepen en kleinschaligheid van de Nederlandse reders.

  12. Cadmium-Aluminum Layered Double Hydroxide Microspheres for Photocatalytic CO2Reduction

    KAUST Repository

    Saliba, Daniel

    2016-03-30

    We report the synthesis of cadmium-aluminum layered double hydroxide (CdAl LDH) using the reaction-diffusion framework. As the hydroxide anions diffuse into an agar gel matrix containing the mixture of aluminum and cadmium salts at a given ratio, they react to give the LDH. The LDH self-assembles inside the pores of the gel matrix into a unique spherical-porous shaped microstructure. The internal and external morphologies of the particles are studied by electron microscopy and tomography revealing interconnected channels and a high surface area. This material is shown to exhibit a promising performance in the photoreduction of carbon dioxide using solar light. Moreover, the palladium-decorated version shows a significant improvement in its reduction potential at room temperature. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Cadmium-Aluminum Layered Double Hydroxide Microspheres for Photocatalytic CO2 Reduction.

    Science.gov (United States)

    Saliba, Daniel; Ezzeddine, Alaa; Sougrat, Rachid; Khashab, Niveen M; Hmadeh, Mohamad; Al-Ghoul, Mazen

    2016-04-21

    We report the synthesis of cadmium-aluminum layered double hydroxide (CdAl LDH) using the reaction-diffusion framework. As the hydroxide anions diffuse into an agar gel matrix containing the mixture of aluminum and cadmium salts at a given ratio, they react to give the LDH. The LDH self-assembles inside the pores of the gel matrix into a unique spherical-porous shaped microstructure. The internal and external morphologies of the particles are studied by electron microscopy and tomography revealing interconnected channels and a high surface area. This material is shown to exhibit a promising performance in the photoreduction of carbon dioxide using solar light. Moreover, the palladium-decorated version shows a significant improvement in its reduction potential at room temperature.

  14. The Origin of the Catalytic Activity of a Metal Hydride in CO2 Reduction.

    Science.gov (United States)

    Kato, Shunsuke; Matam, Santhosh Kumar; Kerger, Philipp; Bernard, Laetitia; Battaglia, Corsin; Vogel, Dirk; Rohwerder, Michael; Züttel, Andreas

    2016-05-10

    Atomic hydrogen on the surface of a metal with high hydrogen solubility is of particular interest for the hydrogenation of carbon dioxide. In a mixture of hydrogen and carbon dioxide, methane was markedly formed on the metal hydride ZrCoHx in the course of the hydrogen desorption and not on the pristine intermetallic. The surface analysis was performed by means of time-of-flight secondary ion mass spectroscopy and near-ambient pressure X-ray photoelectron spectroscopy, for the in situ analysis. The aim was to elucidate the origin of the catalytic activity of the metal hydride. Since at the initial stage the dissociation of impinging hydrogen molecules is hindered by a high activation barrier of the oxidised surface, the atomic hydrogen flux from the metal hydride is crucial for the reduction of carbon dioxide and surface oxides at interfacial sites.

  15. Photocatalytic CO2 Reduction by Periodic Mesoporous Organosilica (PMO) Containing Two Different Ruthenium Complexes as Photosensitizing and Catalytic Sites.

    Science.gov (United States)

    Kuramochi, Yusuke; Sekine, Masato; Kitamura, Kyohei; Maegawa, Yoshifumi; Goto, Yasutomo; Shirai, Soichi; Inagaki, Shinji; Ishida, Hitoshi

    2017-08-01

    A periodic mesoporous organosilica (PMO) containing 2,2'-bipyridine (bpy) ligands within the framework (BPy-PMO) has great potential for designing novel catalysts by modifying metal complexes. A photosensitizing site (Ru(PS)) was introduced by treating cis-[Ru(bpy)2 (dimethylsulfoxide)Cl]Cl with BPy-PMO. Then a catalytic site (Ru(Cat)) was brought in Ru(PS)x -BPy-PMO by reaction with a ruthenium polymer [Ru(CO)2 Cl2 ]n . The stepwise modification of BPy-PMO successfully affords a novel photocatalyst Ru(PS)x -Ru(Cat)y -BPy-PMO. The molar fractions (x, y) of Ru(PS) and Ru(Cat) were determined by energy dispersive X-ray (EDX) measurement and quantification of the amount of CO emitted in the photo-decarbonylation of Ru(Cat), respectively. Photochemical CO2 reduction (λex >430 nm) by Ru(PS)x -Ru(Cat)y -BPy-PMO in a CO2 -saturated N,N-dimethylacetamide/water solution containing 1-benzyl-1,4-dihydronicotinamide catalytically produced CO and formate. The total turnover frequency of CO and formate reached more than 162 h(-1) on x=0.11 and y=0.0055. The product selectivity (CO/formate) became large when the ratio of Ru(PS)-to-Ru(Cat) (x/y) was increased. The photocatalysts can be recycled at least three times without losing their catalytic activity, demonstrating that the Ru(PS) and Ru(Cat) units were strongly immobilized on the BPy-PMO framework. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Fixation of CO2 by electrocatalytic reduction to synthesis of dimethyl carbonate in ionic liquid using effective silver-coated nanoporous copper composites

    Institute of Scientific and Technical Information of China (English)

    Xuan Yun Wang; Su Qin Liu; Ke Long Huang; Qiu Ju Feng; De Lai Ye; Bing Liu; Jin Long Liu; Guan Hua Jin

    2010-01-01

    With high surface area, open porosity and high efficiency, a catalyst was prepared and firstly employed in electrocatalytic reduction of CO2 and electrosynthesis of dimethyl carbonate (DMC). The electrochemical property for electrocatalytic reduction of CO2 in ionic liquid was studied by cyclic voitammogram (CV). The effects of various reaction variables like temperature, working potential and cathode materials on the electrocatalytic performance were also investigated. 80% yield of DMC was obtained under the optimal reaction conditions.

  17. Surface-Plasmon-Enhanced Photodriven CO2 Reduction Catalyzed by Metal-Organic-Framework-Derived Iron Nanoparticles Encapsulated by Ultrathin Carbon Layers.

    Science.gov (United States)

    Zhang, Huabin; Wang, Tao; Wang, Junjie; Liu, Huimin; Dao, Thang Duy; Li, Mu; Liu, Guigao; Meng, Xianguang; Chang, Kun; Shi, Li; Nagao, Tadaaki; Ye, Jinhua

    2016-05-01

    Highly efficient utilization of solar light with an excellent reduction capacity is achieved for plasmonic Fe@C nanostructures. By carbon layer coating, the optimized catalyst exhibits enhanced selectivity and stability applied to the solar-driven reduction of CO2 into CO. The surface-plasmon effect of iron particles is proposed to excite CO2 molecules, and thereby facilitates the final reaction activity.

  18. Evaluation of different catalysts and development of a new catalyst for the reduction of CO2 to graphite

    Science.gov (United States)

    Tschekalinskij, Alexander; Schindler, Matthias; Kretschmer, Wolfgang

    2016-02-01

    We present an evaluation of different catalysts, methods and parameters for the catalytic reduction of CO2 for 14C-AMS graphite targets for radiocarbon measurement at the Physical Institute of the University Erlangen-Nuremberg in Germany. Currently 10 μm iron powder is used as a catalyst to reduce carbon dioxide to graphite following our standard protocol. An optimal catalyst should provide a short reduction time, no additional fractionation effects, a good reduction yield, lack sintering and should not contain any amounts of both "dead" and "modern" carbon. Seven purchasable catalysts have been evaluated regarding this criteria. Further, the method using zinc and titanium hydride instead of hydrogen gas and the water-trap has been applied to our system and the effect of the water-trap temperature on the reduction time has been tested. A self-made catalyst was produced using aluminum oxide impregnated with iron nitrate. The results of this study indicate three good catalysts and show the success of the applied methods on standard samples like Ox II and Alfa graphite.

  19. Turning on the Protonation-First Pathway for Electrocatalytic CO2 Reduction by Manganese Bipyridyl Tricarbonyl Complexes.

    Science.gov (United States)

    Ngo, Ken T; McKinnon, Meaghan; Mahanti, Bani; Narayanan, Remya; Grills, David C; Ertem, Mehmed Z; Rochford, Jonathan

    2017-02-22

    Electrocatalytic reduction of CO2 to CO is reported for the complex, {fac-Mn(I)([(MeO)2Ph]2bpy)(CO)3(CH3CN)}(OTf), containing four pendant methoxy groups, where [(MeO)2Ph]2bpy = 6,6'-bis(2,6-dimethoxyphenyl)-2,2'-bipyridine. In addition to a steric influence similar to that previously established [Sampson, M. D. et al. J. Am. Chem. Soc. 2014, 136, 5460-5471] for the 6,6'-dimesityl-2,2'-bipyridine ligand in [fac-Mn(I)(mes2bpy)(CO)3(CH3CN)](OTf), which prevents Mn(0)-Mn(0) dimerization, the [(MeO)2Ph]2bpy ligand introduces an additional electronic influence combined with a weak allosteric hydrogen-bonding interaction that significantly lowers the activation barrier for C-OH bond cleavage from the metallocarboxylic acid intermediate. This provides access to the thus far elusive protonation-first pathway, minimizing the required overpotential for electrocatalytic CO2 to CO conversion by Mn(I) polypyridyl catalysts, while concurrently maintaining a respectable turnover frequency. Comprehensive electrochemical and computational studies here confirm the positive influence of the [(MeO)2Ph]2bpy ligand framework on electrocatalytic CO2 reduction and its dependence upon the concentration and pKa of the external Brønsted acid proton source (water, methanol, trifluoroethanol, and phenol) that is required for this class of manganese catalyst. Linear sweep voltammetry studies show that both phenol and trifluoroethanol as proton sources exhibit the largest protonation-first catalytic currents in combination with {fac-Mn(I)([(MeO)2Ph]2bpy)(CO)3(CH3CN)}(OTf), saving up to 0.55 V in overpotential with respect to the thermodynamically demanding reduction-first pathway, while bulk electrolysis studies confirm a high product selectivity for CO formation. To gain further insight into catalyst activation, time-resolved infrared (TRIR) spectroscopy combined with pulse-radiolysis (PR-TRIR), infrared spectroelectrochemistry, and density functional theory calculations were used to establish

  20. Reduction of Aldehydes by Fe-H2O-CO2 System in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    HUANG Xi-zhe; JIANG Huan-feng

    2008-01-01

    @@ 1 Introduction Nowadays,green chemistry has received in creased attention.The use of water and scCO2 as a solvent or reagent is an important field for organic reactions and green chemistry both in laboratory and industry[1-4]. The reduction of aldehydes to the corresponding alcohols is an important reaction in organic synthesis and an important step in the synthesis of biologically active compounds[5,6].A number of reducing systems utilized have been developed for this purpose,including H2 catalyzed by metals[7,8],NaBH4[9],and Al-MFn-H2O[10].However,all the procedures suffered from many disadvantages,such as moisture-sensitive,low chemoselectivity,presence of a pyrophoric expensive catalyst and lack of environmentally benign processes.

  1. Selectivity on Etching: Creation of High-Energy Facets on Copper Nanocrystals for CO2 Electrochemical Reduction.

    Science.gov (United States)

    Wang, Zhenni; Yang, Guang; Zhang, Zhaorui; Jin, Mingshang; Yin, Yadong

    2016-04-26

    Creating high-energy facets on the surface of catalyst nanocrystals represents a promising method for enhancing their catalytic activity. Herein we show that crystal etching as the reverse process of crystal growth can directly endow nanocrystal surfaces with high-energy facets. The key is to avoid significant modification of the surface energies of the nanocrystal facets by capping effects from solvents, ions, and ligands. Using Cu nanocubes as the starting material, we have successfully demonstrated the creation of high-energy facets in metal nanocrystals by controlled chemical etching. The etched Cu nanocrystals with enriched high-energy {110} facets showed significantly enhanced activity toward CO2 reduction. We believe the etching-based strategy could be extended to the synthesis of nanocrystals of many other catalysts with more active high-energy facets.

  2. Synthesis of Hierarchical (BiO)2CO3 Nanosheets Microspheres toward Efficient Photocatalystic Reduction of CO2 into CO

    Science.gov (United States)

    Yang, Huohai; Bai, Yang; Chen, Ting; Shi, Xian; Zhu, Yu-chuan

    2016-04-01

    In this paper, hierarchical (BiO)2CO3 nanosheets microspheres were synthesized with dry ice as carbon source, and characterized by X-ray diffraction (XRD) patterns, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM) and UV-vis diffuse reflectance spectra (DRS). The photocatalytic results showed that (BiO)2CO3 display much higher photocatalytic activity than BiOCl and TiO2 for photocatalystic reduction of CO2 under UV-visible light. The photocatalytic mechanism study revealled that (BiO)2CO3 display better separation efficiency of photoinduced charge carriers due to the large interlayer spacing (1.3675 nm).

  3. Facile synthesis of Bi2S3 nanoribbons for photocatalytic reduction of CO2 into CH3OH

    Science.gov (United States)

    Jin, Jiarui; He, Tao

    2017-02-01

    The bismuth sulfide (Bi2S3) nanoribbons with different length-to-width ratio are successfully prepared using a simple solvothermal technique. Their crystal structures, morphologies, as well as the optical absorption are characterized by powder X-ray diffraction, transmission electron microscope, UV-vis diffuse-reflection spectroscopy and nitrogen adsorption. The electron microscopy observation shows that the molar ratio of Bi and S source greatly influences the size of the as-prepared Bi2S3 nanoribbons and, thereby, the length-to-width ratio. The Bi2S3 nanocatalysts with the largest length-to-width ratio exhibits the highest activity for photocatalytic reduction of CO2 into methanol because it has the most negative potential of conduction band, the largest BET specific surface area and lowest recombination of photogenerated charge carriers.

  4. Large CO2 reductions via offshore wind power matched to inherent storage in energy end-uses

    Science.gov (United States)

    Kempton, Willett; Archer, Cristina L.; Dhanju, Amardeep; Garvine, Richard W.; Jacobson, Mark Z.

    2007-01-01

    We develop methods for assessing offshore wind resources, using a model of the vertical structure of the planetary boundary layer (PBL) over water and a wind-electric technology analysis linking turbine and tower limitations to bathymetry and continental shelf geology. These methods are tested by matching the winds of the Middle-Atlantic Bight (MAB) to energy demand in the adjacent states (Massachusetts through North Carolina, U.S.A.). We find that the MAB wind resource can produce 330 GW average electrical power, a resource exceeding the region's current summed demand for 73 GW of electricity, 29 GW of light vehicle fuels (now gasoline), and 83 GW of building fuels (now distillate fuel oil and natural gas). Supplying these end-uses with MAB wind power would reduce by 68% the region's CO2 emissions, and reduce by 57% its greenhouse gas forcing. These percentages are in the range of the global reductions needed to stabilize climate.

  5. 中国电力行业CO2减排潜力及其贡献因素%Factors contributing to CO2 emission reduction potential of the power sector in China

    Institute of Scientific and Technical Information of China (English)

    顾佰和; 谭显春; 穆泽坤; 曾元

    2015-01-01

    Reducing carbon emissions from the power sector is of great importance for China in moving towards a low-carbon economy. Key issues include how to scientifically analyze potential for reductions, identifying a feasible transition strategy, and developing effective policies and measures to achieve goals. Many studies have explored future CO2 emissions from the power sector, but few have quantitatively analyzed factors associated with CO2 emission reduction potential, and research has thus failed to propose targeted policy solutions. This study was built on a CO2 emissions accounting model with a bottom-up approach. Factors that impact the CO2 emissions, i.e., terminal electricity consumption, low-carbon power production, thermal power efficiency, and line loss rate, were included in the model. The LMDI method was used to measure the weight of the contribution from each factor. Three scenarios, i.e. a Business As Usual (BAU) Scenario, a Current Policy (CP) Scenario, and a Low-carbon ( LC) Policy Scenario, were developed to stimulate emission reductions by the sector during the period 2015—2020. The study results reveal that CO2 emissions from China′s power sector will continue to grow under all three scenarios over the period of 2010 to 2020, with annual growth rates of 10.7% (BAU), 6.5% (CP) and 4.5%( LC) . As the Current Policy Scenario was based on existing plans and policies for the power sector, we believe that it should be possible to achieve the 2701 Mt CO2 emission reduction forecast under CP. As the Low-carbon Policy Scenario requires more radical policies to be adopted in the power sector, we believe that the forecast 3688 Mt reduction by 2020 ( down to only 4720 Mt ) is likely to be the upper limit of CO2 emission reductions possible for the sector. By further studying all the factors that contribute to CO2 emission reduction potential, we found that the most influential factor driving the growth of CO2 emissions from the sector until 2020 is terminal

  6. The CO2 Reduction Potential of Combined Heat and Power in California's Commercial Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Stadler, Michael; Marnay, Chris; Cardoso, Goncalo; Lipman, Tim; Megel, Olivier; Ganguly, Srirupa; Siddiqui, Afzal; Lai, Judy

    2009-11-16

    The Ernest Orlando Lawrence Berkeley National Laboratory (LBNL) is working with the California Energy Commission (CEC) to determine the potential role of commercial sector distributed generation (DG) with combined heat and power (CHP) capability deployment in greenhouse gas emissions (GHG) reductions. CHP applications at large industrial sites are well known, and a large share of their potential has already been harvested. In contrast, relatively little attention has been paid to the potential of medium-sized commercial buildings, i.e., ones with peak electric loads ranging from 100 kW to 5 MW. We examine how this sector might implement DG with CHP in cost minimizing microgrids that are able to adopt and operate various energy technologies, such as solar photovoltaics (PV), on-site thermal generation, heat exchangers, solar thermal collectors, absorption chillers, and storage systems. We apply a mixed-integer linear program (MILP) that minimizes a site's annual energy costs as its objective. Using 138 representative mid-sized commercial sites in California (CA), existing tariffs of three major electricity distribution ultilities plus a natural gas company, and performance data of available technology in 2020, we find the GHG reduction potential for this CA commercial sector segment, which represents about 35percent of total statewide commercial sector sales. Under the assumptions made, in a reference case, this segment is estimated to be capable of economically installing 1.4 GW of CHP, 35percent of the California Air Resources Board (CARB) statewide 4 GW goal for total incremental CHP deployment by 2020. However, because CARB's assumed utilization is far higherthan is found by the MILP, the adopted CHP only contributes 19percent of the CO2 target. Several sensitivity runs were completed. One applies a simple feed-in tariff similar to net metering, and another includes a generous self-generation incentive program (SGIP) subsidy for fuel cells. The feed

  7. 分解炉内不同CO2体积分数下的煤粉及煤焦还原NO特性%NO Reduction by Coal and Char at Different CO2 Concentrations in Cement Precalciner

    Institute of Scientific and Technical Information of China (English)

    吕刚; 陆继东; 刘智湘; 薛锦添; 谢新华; 曾阔; 胡芝娟

    2012-01-01

    The reduction of NO by two types of coal and one type of char at different CO2 concentrations in a suspension reactor has been investigated in a high temperature gas solid reactor of industry precalciner. The effects of cement raw meal, limestone and the production of raw meal decomposition on the reduction of NO under different CO2 concentrations were also discussed. The results show that, with the increase of CO2 concentration, the rates of NO reduction by coal and char increase, while the valley value of NO concentration decreases. Cement raw meal, limestone and the production of raw meal decomposition have positive effect on the reduction of NO, and the production of raw meal decomposition shows the strongest catalytic activity. However, the catalytic activity of cement raw meal, limestone and the production of raw meal decomposition becomes weaker with the increase of CO2 concentration.%利用高温气固悬浮实验台对水泥行业中两种典型煤粉及一种煤焦在不同CO2体积分数的气氛下对NO的还原特性进行了实验研究,并考察了添加生料、石灰石及生料分解产物对煤焦及煤粉还原NO的影响特性.研究结果表明,气氛中CO2体积分数升高,煤焦及煤粉对NO的还原速率均增大,NO气体体积分数的谷值降低.水泥生料及石灰石对煤粉及煤焦还原NO的反应具有正催化作用;而水泥生料的分解产物对NO还原的正催化作用最强.随着气氛中CO2体积分数的升高,添加生料、石灰石及生料分解产物对煤焦及煤粉还原NO的促进作用相对减弱.

  8. 2020年我国水泥行业CO2排放趋势与减排路径分析%Analysis on CO2 Emission Trend and Emission Reduction Path of China's Cement Industry in 2020

    Institute of Scientific and Technical Information of China (English)

    蒋小谦; 康艳兵; 刘强; 赵盟

    2012-01-01

    我国水泥行业的CO2排放仅次于电力行业,约占全国排放总量的15%.分析水泥行业的CO2排放趋势和减排路径对实现我国温室气体排放控制目标有着重要的现实意义.本文从影响水泥行业排放的主要影响因素着手,分析了水泥产量和单耗的现状及未来发展趋势,计算了水泥行业的历史排放、发展趋势以及减排潜力,指出了实现减排潜力面临的挑战和障碍,以及相应的措施建议.%CO2 emission from China's cement industry is only second to power industry, accounted for 15% of total national emissions. Analysis on CO2 emission trend and emission reduction path of cement industry is significant to the realization of GHG emissions control target in China. From the perspective of major influencing factors, this paper analyzes the status and future trend of cement production and energy consumption per unit of product, calculates history and future emissions as well as emission reduction potentials, also analyzes challenges and obstacles, and proposes appropriate measures recommendations.

  9. Fiscal 1996 survey of potential international cooperation for a long-term scenario on CO2 reduction; 1996 nendo CO2 sakugen ni kakawaru choki shinario ni kansuru kokusai kyoryoku kanosei chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    For the purpose of working out a CO2 reduction scenario and a CO2 policy introduction scenario, a survey was conducted of comparisons between ten and several models which are world-known and models of the New Earth 21, potential international cooperation to be carried out in the future, etc. The survey included organizations which are developing CO2 policy evaluation models, survey reports made in the past, details of literature for the analysis and arrangement. From the result, details of the questionnaire survey and organizations to be surveyed were decided on for the questionnaire survey. Objects for the survey were 7 countries and 22 organizations, and survey items were places for information exchange, sending/receiving of researchers, exchange of input data, comparative calculation based on the common database, joint research work, economy, the carbon tax, impact, renewable energy, how to handle and think of the carbon isolation, etc. As a result of the survey, proposed were a workshop on CO2 reduction, a comparative study of simulation models, etc. 25 refs., 50 figs., 12 tabs.

  10. Measures for global environmental issues using information communication. Results of trial calculation of CO2 reduction reported by the Telecommunication Council; Joho tsushin wo katsuyoshita chikyu kankyo mondai eno taio. Denki tsushin shingikai toshin no CO2 sakugen shisan kekka

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, T. [Ministry of Posts and Telecommunications, Tokyo (Japan)

    1998-11-01

    Telework is an effective work style using information communication without commutation, and ITS is an integrated traffic system such as advanced navigation. Effects of the CO2 emission reduction by these information communication systems were calculated as a trial. Reduction of CO2 4.06 million ton was obtained, which is equivalent to about 7% of the reduction target 56.5 million ton in Japan by 2010. For the items, were obtained 1.29 million ton (MT) by telework, 1.1 MT by ITS, 0.53 MT by the reduction of paper consumption/rejection using LAN, and 0.5 MT by the alternation of movements for international business using Internet (reduction of overseas official trips). In addition, were obtained 0.36 MT by the energy saving with enhanced efficiency of office environment using advanced information communication such as building management information systems, 0.25 MT by the electronic publication and newspaper for the reduction of paper consumption/rejection using electronic media such as CD-ROM, and 0.03 MT by the remote education and at-home education systems. The trial calculations were conducted only for these seven systems, and only for the direct effects using these systems. Accordingly, the result is only a part of the whole. These systems promote to realize a society with reduced environmental loads. 2 tabs.

  11. Potential reduction of CO2 emissions and low carbon scenario for the Brazilian industrial sector for 2030; Potencial de reducao de emissoes de Co2 e cenario de baixo carbono para o setor industrial brasileiro para 2030

    Energy Technology Data Exchange (ETDEWEB)

    Henriques Junior, Mauricio F. [Instituto Nacional de Tecnologia (INT), Rio de Janeiro, RJ (Brazil)], email: mauricio.henriques@int.gov.br; Schaeffer, Roberto [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil)], email: roberto@ppe.ufrj.br

    2010-07-01

    This study discusses the potential for reducing carbon dioxide (CO2) emissions from energy use by the Brazilian industrial sector in a low-carbon scenario over a horizon until 2030. It evaluates the main mitigation measures, the quantities of this gas avoided and the respective abatement costs. In relation to a benchmark scenario projected for 2030, the reduction of CO2 emissions estimated here can reach 40% by adopting energy efficiency measures, materials recycling, cogeneration, shifting from fossil fuels to renewable or less carbon content sources, and eliminating the use of biomass from deforestation. The set of measures studied here would bring cumulative emissions reductions of nearly 1.5 billion tCO2 over a period of 20 years (2010-2030). This would require huge investments, but the majority of them would have significant economic return and negative abatement costs. However, in the cases there would be low economic attractiveness and higher abatement costs, thus requiring more effective incentives and a collective effort, from both the public and private sectors. (author)

  12. Reversible potentials for steps in methanol and formic acid oxidation to CO2; adsorption energies of intermediates on the ideal electrocatalyst for methanol oxidation and CO2 reduction.

    Science.gov (United States)

    Anderson, Alfred B; Asiri, Haleema Aied

    2014-06-14

    Quantum chemical theory is used to identify the reasons for platinum's limitations as an electrocatalyst for oxidizing methanol at fuel cell anodes. The linear Gibbs energy relation (LGER) method is employed to predict reversible potentials for reaction steps for intermediates on the electrode surface. In this procedure, standard reversible potentials are calculated for the reactions in bulk solution phase and then they are perturbed using calculated adsorption bond strengths to the electrode surface, yielding the equilibrium potentials for each electron transfer step for adsorbed intermediates. Adsorption properties of ideal electrocatalysts for the methanol oxidation are found by imposing the condition that the reversible potential of each electron transfer step equals that for the overall reaction. The adsorption bond strengths that provide the ideal properties also apply to formic acid oxidation and carbon dioxide reduction. It is instructive to think of the ideal electrocatalyst as a lens that focusses the reversible potentials for the n individual electron transfer steps to the reversible potential for the n-electron process. It is found that the ideal catalyst will adsorb many intermediates, including HOOC, CO, OCH, HOC, HOCH, HOCH2, and OCH3 more weakly than platinum, and OOCH and OH more strongly. For example, for one possible pathway it is necessary to weaken adsorption bond strengths for HOCH2, HOCH, OCH, HOOC by about 0.5 eV, weaken adsorption CO by about 1.1 eV and strengthen OH adsorption by about 0.6 eV. These results imply a need for developing new multi-component catalysts.

  13. Tin oxide dependence of the CO2 reduction efficiency on tin electrodes and enhanced activity for tin/tin oxide thin-film catalysts.

    Science.gov (United States)

    Chen, Yihong; Kanan, Matthew W

    2012-02-01

    The importance of tin oxide (SnO(x)) to the efficiency of CO(2) reduction on Sn was evaluated by comparing the activity of Sn electrodes that had been subjected to different pre-electrolysis treatments. In aqueous NaHCO(3) solution saturated with CO(2), a Sn electrode with a native SnO(x) layer exhibited potential-dependent CO(2) reduction activity consistent with previously reported activity. In contrast, an electrode etched to expose fresh Sn(0) surface exhibited higher overall current densities but almost exclusive H(2) evolution over the entire 0.5 V range of potentials examined. Subsequently, a thin-film catalyst was prepared by simultaneous electrodeposition of Sn(0) and SnO(x) on a Ti electrode. This catalyst exhibited up to 8-fold higher partial current density and 4-fold higher faradaic efficiency for CO(2) reduction than a Sn electrode with a native SnO(x) layer. Our results implicate the participation of SnO(x) in the CO(2) reduction pathway on Sn electrodes and suggest that metal/metal oxide composite materials are promising catalysts for sustainable fuel synthesis.

  14. Study on Shanghai Residents’ Willingness to Pay for CO2 Emission Reduction in Electric Power Industry%上海居民对电力行业CO2减排支付意愿研究

    Institute of Scientific and Technical Information of China (English)

    刘骏

    2016-01-01

    The article uses CVM contingent valuation method to build up Logit regression model based on 5436 units survey data in order to estimate Shanghai residents’ willingness to pay for CO2 emission reduction strategy instead of coal-fired power generation. The result shows that most of Shanghai residents hold supportive attitude to pay for CO2 emission reduction strategy. Rate of support to use natural gas-fired power generation instead of coal-fired power generation is 7 times as much as to use nuclear power generation instead of coal-fired power generation. It figures out that increased natural gas power generation contributes to realization of emission reduction targets. Otherwise, the model shows that age, income level, education level and residence period of Shanghai residents as four social economic characteristics significantly affect results of their willingness to pay for CO2 emission reduction strategy.%利用条件价值评估法,对5436组有效调查问卷数据,建立Logit回归模型,估算上海地区民众对代替煤电进行CO2减排策略的支付意愿。结果表明,大多数上海民众对CO2减排策略持支持的态度,对天然气发电代替煤电的支付意愿大约是核电代替煤电的7倍,并发现增加天然气发电更加有利于减排目标的实现。另外模型显示,居民的年龄、收入水平、受教育程度、居住年限等四项社会经济特征显著影响着支付意愿结果。

  15. Role of Pyridine as a Biomimetic Organo-Hydride for Homogeneous Reduction of CO2 to Methanol

    CERN Document Server

    Lim, Chern-Hooi; Hynes, James T; Musgrave, Charles B

    2014-01-01

    We use quantum chemical calculations to elucidate a viable homogeneous mechanism for pyridine-catalyzed reduction of CO2 to methanol. In the first component of the catalytic cycle, pyridine (Py) undergoes a H+ transfer (PT) to form pyridinium (PyH+) followed by an e- transfer (ET) to produce pyridinium radical (PyH0). Examples of systems to effect this ET to populate the LUMO of PyH+(E0calc ~ -1.3V vs. SCE) to form the solution phase PyH0 via highly reducing electrons include the photo-electrochemical p-GaP system (ECBM ~ -1.5V vs. SCE at pH= 5) and the photochemical [Ru(phen)3]2+/ascorbate system. We predict that PyH0 undergoes further PT-ET steps to form the key closed-shell, dearomatized 1,2-dihydropyridine (PyH2) species. Our proposed sequential PT-ET-PT-ET mechanism transforming Py into PyH2 is consistent with the mechanism described in the formation of related dihydropyridines. Because it is driven by its proclivity to regain aromaticity, PyH2 is a potent recyclable organo-hydride donor that mimics the ...

  16. The "Origin-of-Life Reactor" and Reduction of CO2 by H2 in Inorganic Precipitates.

    Science.gov (United States)

    Jackson, J Baz

    2017-08-01

    It has been suggested that inorganic membranes were forerunners of organic membranes at the origin of life. Such membranes, interposed between alkaline fluid in submarine vents and the more acidic Hadean ocean, were thought to house inorganic molecular machines. H(+) flowed down the pH gradient (ΔpH) from ocean to vent through the molecular machines to drive metabolic reactions for early life. A set of experiments was performed by Herschy et al. (J Mol Evol 79:213-227, 2014) who followed earlier work to construct inorganic precipitate membranes which, they argued, would be transected by a ΔpH. They supposed that inorganic molecular machines might assemble by chance in the precipitate membranes, and be capable of using the ΔpH to drive unfavourable reduction of CO2 by H2 to formate and formaldehyde. Indeed, these workers detected both of these compounds in their origin-of-life reaction vessel and contend this was proof of principle for their hypothesis. However, it is shown here by a straightforward calculation that the formate produced was only that which reached on approach to equilibrium without any driving force from ΔpH. We conclude that the reaction was facilitated by isotropic catalysts in the precipitate membrane but not by an anisotropic ΔpH-driven molecular machine.

  17. Outline of possible climate measures. Local Climate Agenda. CO2 reduction, employment, cost for the government and living expenses; Verkenning mogelijke klimaatmaatregelen. Lokale Klimaatagenda. CO2-reductie, werkgelegenheid, kosten voor de overheid en woonlasten

    Energy Technology Data Exchange (ETDEWEB)

    Elzenga, H. [Planbureau voor de Leefomgeving PBL, Den Haag (Netherlands); Tigchelaar, C.; Menkveld, M.; Lensink, S. [ECN Beleidsstudies, Petten (Netherlands)

    2013-03-15

    The Environmental Assessment Agency (PBL) and the Energy research Centre of the Netherlands (ECN) estimated the effects of eight policy measures for the year 2020 on renewable energy, energy saving, CO2 reduction, cost to the government, employment and living expenses. The goal was for the Local Climate Agenda to identify several cost-effective policies The Local Climate Agenda is a joint agenda of representatives of local authorities and of the Dutch government [Dutch] Het Planbureau voor de Leefomgeving en het Energieonderzoek Centrum Nederland (ECN) hebben de effecten in 2020 geraamd van een achttal beleidsmaatregelen op hernieuwbare energie, energiebesparing, CO2-reductie, kosten voor de overheid, werkgelegenheid en woonlasten. Het doel was om ten behoeve van de Lokale Klimaatagenda 'Werk maken van klimaat' een aantal kosteneffectieve beleidsmaatregelen te identificeren. Deze Klimaatagenda is een gezamenlijke agenda van zowel vertegenwoordigers van decentrale overheden als van het Rijk.

  18. Performance evaluation of non-thermal plasma on particulate matter, ozone and CO2 correlation for diesel exhaust emission reduction

    DEFF Research Database (Denmark)

    Babaie, Meisam; Davari, Pooya; Talebizadeh, Poyan

    2015-01-01

    This study is seeking to investigate the effect of non-thermal plasma technology in the abatement of particulate matter (PM) from the actual diesel exhaust. Ozone (O3) strongly promotes PM oxidation, the main product of which is carbon dioxide (CO2). PM oxidation into the less harmful product (CO2...

  19. Effects of elevated CO2 concentration and nitrogen supply on biomass and active carbon of freshwater marsh after two growing seasons in Sanjiang plain, Northeast China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Guangying; LIU Jingshuang; WANG Yang; DOU Jingxin; DONG Xiaoyong

    2009-01-01

    An experiment was carried out with treatments differing in nitrogen supply (0, 5 and 15 g N/m2) and CO2 level (350 and 700 μmol/mol) using OTC (open top chamber) equipment to investigate the biomass of Calamagrostis angustifolia and soil active carbon contents after two years. The results showed that elevated CO2 concentration increased the biomass of C. angustifolia and the magnitude of response varied with each growth period. Elevated CO2 concentration has increased aboveground biomass by 16.7% and 17.6% during the jointing and heading periods and only 3.5% and 9.4% during dough and maturity periods. The increases in belowground biomass due to CO2 elevation was 26.5%, 34.0% and 28.7% during the heading, dough and maturity periods, respectively. The response of biomass to enhanced CO2 concentration differed in N levels. Both the increase of aboveground biomass and belowground biomass were greater under high level of N supply (15 g N/m2). Elevated CO2 concentration also increased the allocation of biomass and carbon in root. Under elevated CO2 concentration, the average values of active carbon tended to increase. The increases of soil active soil contents followed the sequence of Microbial biomass carbon (10.6%) > dissolved organic carbon (7.5%) > oxidable labile carbon (6.6%) > carbohydrate carbon (4.1%). Stepwise regressions indicated there were significant correlations between the soil active carbon contents and plant biomass. Particularly, microbial carbon, oxidable labile carbon and carbohydrate carbon were found to be correlated with belowground biomass, while dissolved organic carbon has correlation with aboveground biomass. Therefore, increased biomass was regarded as the main driving force for the increase in soil active organic carbon under elevated CO2 concentration.

  20. Modeling Effects of Bicarbonate Release on Carbonate Chemistry and pH of the North Sea: A Pilot Study for Atmospheric CO2 Reduction

    Science.gov (United States)

    Lettmann, K.; Kirchner, J.; Schnetger, B.; Wolff, J. O.; Brumsack, H. J.

    2016-12-01

    Rising CO2-emissions accompanying the industrial revolution are the main drivers for climate change and ocean acidification. Several methods have been developed to capture CO2 from effluents and reduce emission. Here, we consider a promising approach that mimics natural limestone weathering: CO2 in effluent gas streams reacts with calcium carbonate in a limestone suspension. The resulting bicarbonate-rich solution can be released into natural systems. In comparison to classical carbon capture and storage (CCS) methods this artificial limestone weathering is cheaper and does not involve using toxic chemical compounds. Additionally there is no need for the controversially discussed storage of CO2 underground. The reduction of CO2-emissions becomes more important for European industries as the EU introduced a system that limits the amount of allowable CO2-emissions. Therefore, large CO2 emitters are forced to find cheap methods for emission reduction, as they often cannot circumvent CO2-production. The method mentioned above is especially of interest for power plants located close to the coast that are already using seawater for cooling purposes. Thus, it is important to estimate the environmental effects if several coastal power plants will release high amounts of bicarbonate-rich waters into coastal waters, e.g. the North Sea. In a first pilot study, the unstructured-grid finite-volume community ocean model (FVCOM) was combined with a chemical submodul (mocsy 2.0) to model the hydrodynamic circulation and mixing of bicarbonate-rich effluents from a gas power plant located at the German North Sea coast. Here, we present the first preliminary results of this project, which include modelled changes of the North Sea carbonate system and changes in pH value after the introduction of these bicarbonate-rich waters on short time scales up to one year.

  1. Compact, Lightweight Adsorber and Sabatier Reactor for CO2 Capture and Reduction for Consumable and Propellant Production

    Science.gov (United States)

    Junaedi, Christian; Hawley, Kyle; Walsh, Dennis; Roychoudhury, Subir; Busby, Stacy A.; Abney, Morgan B.; Perry, Jay L.; Knox, James C.

    2012-01-01

    The utilization of CO2 to produce (or recycle) life support consumables, such as O2 and H2O, and to generate propellant fuels is an important aspect of NASA's concept for future, long duration planetary exploration. One potential approach is to capture and use CO2 from the Martian atmosphere to generate the consumables and propellant fuels. Precision Combustion, Inc. (PCI), with support from NASA, continues to develop its regenerable adsorber technology for capturing CO2 from gaseous atmospheres (for cabin atmosphere revitalization and in-situ resource utilization applications) and its Sabatier reactor for converting CO2 to methane and water. Both technologies are based on PCI's Microlith(R) substrates and have been demonstrated to reduce size, weight, and power consumption during CO2 capture and methanation process. For adsorber applications, the Microlith substrates offer a unique resistive heating capability that shows potential for short regeneration time and reduced power requirements compared to conventional systems. For the Sabatier applications, the combination of the Microlith substrates and durable catalyst coating permits efficient CO2 methanation that favors high reactant conversion, high selectivity, and durability. Results from performance testing at various operating conditions will be presented. An effort to optimize the Sabatier reactor and to develop a bench-top Sabatier Development Unit (SDU) will be discussed.

  2. Photocatalytic reduction of CO2 over Ag/TiO2 nanocomposites prepared with a simple and rapid silver mirror method

    Science.gov (United States)

    Yu, Bingcheng; Zhou, Yong; Li, Peng; Tu, Wenguang; Li, Ping; Tang, Lanqin; Ye, Jinhua; Zou, Zhigang

    2016-06-01

    The photocatalytic reduction of CO2 over Ag/TiO2 composites prepared with a simple silver mirror reaction method was investigated under UV-visible irradiation in both gas-phase (CO2 + water vapor) and aqueous solution (CO2-saturated NaHCO3 solution) systems. The as-prepared Ag/TiO2 nanocomposite exhibits efficient photocatalytic activity due to the surface plasmonic resonance and electron sink effect of the Ag component, which was found to be closely related to the size and loading amount of Ag. The rapid silver method is effective at curbing the size of Ag, so photocatalytic activity can be improved. Diverse organic chemical products were detected, including mainly methane and methanol as well as a small amount of C2 and C3 species such as acetaldehyde and acetone. Possible photocatalytic mechanisms were proposed. This artificial photosynthesis process may give a prosperous route to the removal of CO2 while simultaneously converting CO2 to valuable fuels based on highly efficient photocatalysts.The photocatalytic reduction of CO2 over Ag/TiO2 composites prepared with a simple silver mirror reaction method was investigated under UV-visible irradiation in both gas-phase (CO2 + water vapor) and aqueous solution (CO2-saturated NaHCO3 solution) systems. The as-prepared Ag/TiO2 nanocomposite exhibits efficient photocatalytic activity due to the surface plasmonic resonance and electron sink effect of the Ag component, which was found to be closely related to the size and loading amount of Ag. The rapid silver method is effective at curbing the size of Ag, so photocatalytic activity can be improved. Diverse organic chemical products were detected, including mainly methane and methanol as well as a small amount of C2 and C3 species such as acetaldehyde and acetone. Possible photocatalytic mechanisms were proposed. This artificial photosynthesis process may give a prosperous route to the removal of CO2 while simultaneously converting CO2 to valuable fuels based on highly

  3. Exhaust Gas Recirculation in Gas Turbines for Reduction of CO2 Emissions; Combustion Testing with Focus on Stability and Emissions

    Directory of Open Access Journals (Sweden)

    Johan E. Hustad

    2005-12-01

    Full Text Available Exhaust gas recirculation can be applied with the intention of reducing CO2 emissions. When a fraction of the exhaust gas is injected in the entry of a gas turbine, the amount of CO2 in the exhaust gas not being recirculated will be higher and less complicated to capture. However, with this change in combustion air composition, especially the reduced concentration of oxygen, the combustion process will be affected. The lower oxygen concentration decreases the stability and the increased amount of CO2, H2O and N2 will decrease the combustion temperature and thus, the NOx emissions. Testing has been performed on a 65 kW gas turbine combustor, to investigate the effect of adding N2, CO2 and O2 in the combustion process, with focus on stability and emissions of NOx. Results show that adding N2 and CO2 decreases the NOx emissions, whereas O2 addition increases the NOx emissions. The tests have been performed both in a diffusion flame (pilot burner and a premixed flame (main burner, and for additives being injected with the fuel or with the air stream. Addition into the fuel stream is proven to affect the NOx emissions the most. The stability limits of the flames are indicated with respect to mass-based additive-to-fuel ratios.

  4. CO2电化学还原研究进展%Advances in Electrochemical Reduction of Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    陶映初; 吴少晖; 张曦

    2001-01-01

    The transformation and mechanism of carbon dioxide by electrochemical methods in hydroxygen solvent and organic solvent have been studied.The fastness of carbon dioxide organic complex and transfer of carbon dioxide by such photoelectrochemical methods as photoelectric cell,photocatalyzation and resemble photosynthesis are described in detail for the purpose of approach a rational and efficient method to alleviate greenhouse effect.%综述了利用电化学方法研究CO2在水溶剂、非水溶剂中的转化情况和机理,以及将CO2固定在有机络合物中或用光电化学、光催化还原CO2及仿光合作用转移CO2的最新研究情况,旨在寻求一种合理、高效的CO2转化方法以缓解温室效应。

  5. Formulation of a Network and the Study of Reaction Paths for the Sustainable Reduction of CO2 Emissions

    DEFF Research Database (Denmark)

    Frauzem, Rebecca; Kongpanna, Pichayapan; Roh, Kosan

    carbonate (DMC) [2]. In this work, through a computer-aided framework for process network synthesis-design, a network of conversion processes that all use emitted CO2 is investigated. CO2 is emitted into the environment from various sources: power generation, industrial processes, transportation...... and commercial processes. Within these there are high-purity emissions and low-purity emissions. Rather than sending these to the atmosphere, it is possible to collect them and use them for other purposes. Targeting some of the largest contributors: power generation, manufacturing, chemical industry...... through the reactions. Studies and detailed simulations have been performed on CO2 conversion to methanol, synthesis gas processes, dimethyl carbonate production, and other processes. The detailed simulations are performed on the paths that are selected based on basic calculations on each path. Then...

  6. CO2-induced pH reduction increases physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus

    Science.gov (United States)

    Hu, Menghong; Lin, Daohui; Shang, Yueyong; Hu, Yi; Lu, Weiqun; Huang, Xizhi; Ning, Ke; Chen, Yimin; Wang, Youji

    2017-01-01

    The increasing usage of nanoparticles has caused their considerable release into the aquatic environment. Meanwhile, anthropogenic CO2 emissions have caused a reduction of seawater pH. However, their combined effects on marine species have not been experimentally evaluated. This study estimated the physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus under high pCO2 (2500–2600 μatm). We found that respiration rate (RR), food absorption efficiency (AE), clearance rate (CR), scope for growth (SFG) and O:N ratio were significantly reduced by nano-TiO2, whereas faecal organic weight rate and ammonia excretion rate (ER) were increased under nano-TiO2 conditions. High pCO2 exerted lower effects on CR, RR, ER and O:N ratio than nano-TiO2. Despite this, significant interactions of CO2-induced pH change and nano-TiO2 were found in RR, ER and O:N ratio. PCA showed close relationships among most test parameters, i.e., RR, CR, AE, SFG and O:N ratio. The normal physiological responses were strongly correlated to a positive SFG with normal pH and no/low nano-TiO2 conditions. Our results indicate that physiological functions of M. coruscus are more severely impaired by the combination of nano-TiO2 and high pCO2.

  7. Localized innovation, localized diffusion and the environment : an analysis of reductions of CO(2) emissions by passenger cars

    NARCIS (Netherlands)

    Los, B.; Verspagen, B.

    2009-01-01

    We investigate technological change with regard to CO(2) emissions by passenger cars, using a Free Disposal Hull methodology to estimate technological frontiers. We have a sample of cars available in the UK market in the period 2000-2007. Our results show that the rates of technological change (fron

  8. Localized innovation, localized diffusion and the environment : an analysis of reductions of CO(2) emissions by passenger cars

    NARCIS (Netherlands)

    Los, B.; Verspagen, B.

    We investigate technological change with regard to CO(2) emissions by passenger cars, using a Free Disposal Hull methodology to estimate technological frontiers. We have a sample of cars available in the UK market in the period 2000-2007. Our results show that the rates of technological change

  9. Assessing the potential impact of the CO2 performance ladder on the reduction of carbon dioxide emissions in the Netherlands

    NARCIS (Netherlands)

    Rietbergen, M.G.; Blok, K.

    2013-01-01

    Green public procurement is often promoted as a tool to reduce energy use and CO2 emissions in the supply chains of public entities. However, only a limited number of studies has quantitatively assessed the environmental impacts of green public procurement schemes. The aim of this paper was to asses

  10. First 2 years of Atmospheric CO2 measurements in the Estany Llong plain (2100 masl, Parc Nacional d'Aigüestortes i Estany de Sant Maurici, Pyrenees, Catalonia, Spain).

    Science.gov (United States)

    Curcoll, Roger; Recolons, Montserrat; Font, Anna; Agraz, Laura; Parga, Elena; Bacardit, Montse; Camarero, Lluís.; Pueyo, Salva; Rodó, Xavier; Morguí, Josep Anton

    2010-05-01

    Since April 2009, air samples are being taken bi-weekly at 10 GMT in the plain of the Estany Llong at 2100 masl. Estany Llong air sampling site (ELL, 42°34'29''N 0°57'17''E) is a remote site situated in the SW principal valley of the Parc Nacional d'Aigüestortes i Estany de Sant Maurici. New Flask-sampling equipment for Remote Mountain Sites was developed by the Institut Català de Ciències del Clima (IC3) to allow flask sampling in extreme weather conditions and carrying the sampling equipment for more than 10 km without damaging flasks. Dry Air analysis for CO2 are done at the Laboratory of IC3 using two coupled modified IRGA Licor-7000, where both pressure and flow are externally controlled. Far away from populated areas, ELL site acts as a remote site, but it is also responding to discrete events as snow melting, summer cattle breeding on pastures and trekking frequentation. Series of CO2 obtained are included as part of Long Term Ecological Research (LTER) at the Parc Nacional d'Aigüestortes i Estany de Sant Maurici. In the long term, these measurements show the mountain ecosystems contribution and geomorphologic influence on the CO2 budget of the air masses crossing a mountain range.

  11. Selective photocatalytic reduction of CO2 to methanol in CuO-loaded NaTaO3 nanocubes in isopropanol

    Directory of Open Access Journals (Sweden)

    Tianyu Xiang

    2016-06-01

    Full Text Available A series of NaTaO3 photocatalysts were prepared with Ta2O5 and NaOH via a hydrothermal method. CuO was loaded onto the surface of NaTaO3 as a cocatalyst by successive impregnation and calcination. The obtained photocatalysts were characterized by XRD, SEM, UV–vis, EDS and XPS and used to photocatalytically reduce CO2 in isopropanol. This worked to both absorb CO2 and as a sacrificial reagent to harvest CO2 and donate electrons. Methanol and acetone were generated as the reduction product of CO2 and the oxidation product of isopropanol, respectively. NaTaO3 nanocubes loaded with 2 wt % CuO and synthesized in 2 mol/L NaOH solution showed the best activity. The methanol and acetone yields were 137.48 μmol/(g·h and 335.93 μmol/(g·h, respectively, after 6 h of irradiation. Such high activity could be attributed to the good crystallinity, morphology and proper amount of CuO loading, which functioned as reductive sites for selective formation of methanol. The reaction mechanism was also proposed and explained by band theory.

  12. Methane Production Pathways in a California Rice Paddy: Isotopic Evidence for Substantial CO2 Reduction as Cause for Isotopically Light Emitted CH4 Carbon

    Science.gov (United States)

    Tyler, S. C.; McMillan, A. M.; Bearden, K.; Chidthaisong, A.; Macalady, J.

    2003-12-01

    We report measurements of δ 13C of emitted CH4 and sediment CH4 and CO2 during the 1999 rice-growing season near Maxwell, CA. Two treatments, one with rice straw incorporated from the previous season and one without rice straw were studied. The δ 13C value of emitted CH4 was consistently lighter isotopically (-67‰ to -83‰ throughout the season) in both straw incorporated and straw removed (burned) plots than in fields we have studied in Texas, Kenya, and Japan. Measured isotopic values of the production zone CH4 were compared to a two-point mixing curve representative of isotopic CH4 produced from either pure methyl-group fermentation or CO2 reduction pathways to partition the production pathways and to track seasonal changes in the production processes. Our sediment CH4 and CO2 isotope data indicate that fermentation was rarely the dominant methanogenic pathway - on the contrary CO2 reduction with H2 was more prevalent than fermentation methanogenesis throughout most of the season. The relatively isotopically light CH4 emitted by the paddy fields is also a product of oxidation and stem-transport processes which have isotopic effects of their own. These effects are discussed in context with the methanogenic isotope effects to provide a complete picture of the paddy field CH4 carbon isotope system.

  13. Effect of Ni+2-substituted Fe2TiO5 on the H2-reduction and CO2 Catalytic Decomposition Reactions at 500℃

    Institute of Scientific and Technical Information of China (English)

    M.H.Khedr

    2006-01-01

    CO2 is a major component of the greenhouse gases, which causes the global warming. To reduce CO2 gas,high activity nanosized Ni+2 substituted Fe2TiO5 samples were synthesized by conventional ceramic method.The effect of the composition of the synthesized ferrite on the H2-reduction and CO2-catalytic decomposition was investigated. Fe2TiO5 (iron titanate) phase that has a nanocrystallite size of ~80 nm is formed as a result of heating Fe2O3 and TiO2 while the addition of NiO leads to the formation of new phases (~80 nm)NiTiO3 and NiFe2O4, but the mixed solid of NiO and Fe2O3 results in the formation of NiFe2O4 only.Samples with Ni+2=0 shows the lowest reduction extent (20%); as the extent of Ni+2 increases, the extent of reduction increases. The increase in the reduction percent is attributed to the presence of NiTiO3 and NiFe2O4 phases, which are more reducible phases than Fe2TiO5. The CO2 decomposition reactions were monitored by thermogravimetric analysis (TGA) experiments. The oxidation of the H2-reduced Ni+2 substituted Fe2TiO5 at 500℃ was investigated. As Ni+2 increases, the rate of reoxidation increases. Samples with the highest reduction extents gave the highest reoxidation extent, which is attributed to the highly porous nature and deficiency in oxygen due to the presence of metallic Fe, Ni and/or FeNi alloy. X-ray diffraction (XRD) and transmission electron microscopy (TEM) of oxidized samples show also the presence of carbon in the sample containing Ni+2>0, which appears in the form of nanotubes (25 nm).

  14. Facile preparation of ordered mesoporous MnCo2O4 for low-temperature selective catalytic reduction of NO with NH3

    Science.gov (United States)

    Qiu, Mingying; Zhan, Sihui; Yu, Hongbing; Zhu, Dandan; Wang, Shengqiang

    2015-01-01

    Ordered mesoporous MnCo2O4 nanomaterials were successfully prepared through the nanocasting route using SBA-15 and KIT-6 as hard templates. These mesoporous nanomaterials were characterized using XRD, BET, TEM, NH3-TPD, H2-TPR, NO-TPD, XPS and DRIFT. The low temperature selective catalytic reduction (SCR) activity of NO with NH3 was investigated, which revealed that 3D-MnCo2O4 using KIT-6 as a template can totally clean all NO over a wide temperature range of 100-250 °C with a gas hourly space velocity (GHSV) of 32 000 h-1, while 2D-MnCo2O4 with SBA-15 as a template had 95% conversion rate at the same condition. 3D-MnCo2O4 showed the best performance to clean NO due to its typical three-dimensional porous structure, large specific surface area, abundant active surface oxygen species and Lewis acid sites. All the results indicate that a novel, cheap catalyst for catalytic removal of NO can be designed by controlling the morphology at the nanoscale.Ordered mesoporous MnCo2O4 nanomaterials were successfully prepared through the nanocasting route using SBA-15 and KIT-6 as hard templates. These mesoporous nanomaterials were characterized using XRD, BET, TEM, NH3-TPD, H2-TPR, NO-TPD, XPS and DRIFT. The low temperature selective catalytic reduction (SCR) activity of NO with NH3 was investigated, which revealed that 3D-MnCo2O4 using KIT-6 as a template can totally clean all NO over a wide temperature range of 100-250 °C with a gas hourly space velocity (GHSV) of 32 000 h-1, while 2D-MnCo2O4 with SBA-15 as a template had 95% conversion rate at the same condition. 3D-MnCo2O4 showed the best performance to clean NO due to its typical three-dimensional porous structure, large specific surface area, abundant active surface oxygen species and Lewis acid sites. All the results indicate that a novel, cheap catalyst for catalytic removal of NO can be designed by controlling the morphology at the nanoscale. Electronic supplementary information (ESI) available: Low-angle XRD

  15. Reduction of CO2 emissions from road transport in cities impact of dynamic route guidance system on greenhouse gas emission

    CERN Document Server

    Markiewicz, Michal

    2017-01-01

    Michal Markiewicz presents the outcomes of his research regarding the influence of dynamic route guidance system on overall emission of carbon dioxide from road transport in rural areas. Sustainable transportation in smart cities is a big challenge of our time, but before electric vehicles replace vehicles that burn fossil fuels we have to think about traffic optimization methods that reduce the amount of greenhouse gas emissions. Contents Comparison of Travel Time Measurements Using Floating Car Data and Intelligent Infrastructure Integration of Cellular Automata Traffic Simulator with CO2 Emission Model Impact of Dynamic Route Guidance System on CO2 Emission Naxos Vehicular Traffic Simulator Target Groups Lecturers and students of computer science, transportation and logistics Traffic engineers The Author Dr. Michal Markiewicz defended his PhD thesis in computer science at the University of Bremen,TZI Technologie-Zentrum Informatik und Informationstechnik, Germany. Currently, he is working on commercializat...

  16. Subsidence and carbon loss in drained tropical peatlands: reducing uncertainty and implications for CO2 emission reduction options

    Directory of Open Access Journals (Sweden)

    A. Idris

    2011-09-01

    Full Text Available Conversion of tropical peatlands to agriculture leads to a release of carbon from previously stable, long-term storage, resulting in land subsidence that can be a surrogate measure of CO2 emissions to the atmosphere. We present an analysis of recent large-scale subsidence monitoring studies in Acacia and oil palm plantations on peatland in SE Asia, and compare the findings with previous studies. Subsidence in the first 5 years after drainage was found to be 142 cm, of which 75 cm occurred in the first year. After 5 years, the subsidence rate in both plantation types, at average water table depths of 0.7 m, remained constant at around 5 cm yr−1. Bulk density profiles indicate that consolidation contributes only 7 % to total subsidence, in the first year after drainage, and that the role of compaction is also reduced quickly and becomes negligible after 5 years. Over 18 years after drainage, 92 % of cumulative subsidence was caused by peat oxidation. The average rate of carbon loss over the first 5 years was 178 t ha−1 yr−1 CO2eq, which reduced to 73 t ha−1 yr−1 CO2eq over subsequent years, resulting in an average loss of 100 t ha−1 yr−1 CO2eq annualized over 25 years. Part of the observed range in subsidence and carbon loss values is explained by differences in water table depth, but vegetation cover and addition of fertilizers also influence peat oxidation. A relationship with groundwater table depth shows that subsidence and carbon loss are still considerable even at the highest water table levels theoretically possible in plantations. This implies that improved water management will reduce these impacts by only 20 % at most, relative to current conditions, and that high rates of carbon loss and land subsidence should be accepted as inevitable consequences of conversion of forested tropical peatlands to other land uses.

  17. Porous dendritic copper: an electrocatalyst for highly selective CO 2 reduction to formate in water/ ionic liquid electrolyte

    OpenAIRE

    Huan, Tran Ngoc; Simon, Philippe; Rousse, Gwenaëlle; Génois, Isabelle; Artero, Vincent; Fontecave, Marc

    2016-01-01

    International audience; Copper is currently extensively studied because it provides promising electrodes for carbon dioxide electroreduction. The original combination, reported here, of a nanostructured porous dendritic Cu-based material, characterized by electron microcopy (SEM, TEM) and X-ray diffraction methods, and a water/ionic liquid mixture as the solvent, contributing to CO 2 solubilization and activation, results in a remarkably efficient (large current densities at low overpotential...

  18. Direct assembly synthesis of metal complex-semiconductor hybrid photocatalysts anchored by phosphonate for highly efficient CO2 reduction.

    Science.gov (United States)

    Suzuki, Tomiko M; Tanaka, Hiromitsu; Morikawa, Takeshi; Iwaki, Masayo; Sato, Shunsuke; Saeki, Shu; Inoue, Masae; Kajino, Tsutomu; Motohiro, Tomoyoshi

    2011-08-14

    Hybrid photocatalysts consisting of a ruthenium complex and p-type photoactive N-doped Ta(2)O(5) anchored with an organic group were successfully synthesized by a direct assembly method. The photocatalyst anchored by phosphonate exhibited excellent photoconversion activity of CO(2) to formic acid under visible-light irradiation with respect to the reaction rate and stability. This journal is © The Royal Society of Chemistry 2011

  19. Effect of a 1 kW Polymer Electrode Fuel Cell system for residential usage on Reduction of CO2 emission

    Directory of Open Access Journals (Sweden)

    Toshiro Kobayashi

    2013-06-01

    Full Text Available In the present paper, the reduction of carbon dioxide by using a Polymer Electrode membrane Fuel Cell (PEFC power generation system for residential usage was verified. The consumption of electric and heat energy of a family introduced PEFC system in Okayama prefecture was recorded for more than one month, then the data were analyzed in comparison with the cases where only commercial electricity is used and electricity and kerosene are used in combination. Furthermore, theeffect of the capacity of hot water tank and the usage of nighttime electric power was estimated. As a result, it was found that the PEFC contributed to reduce CO2 emission more than 22%, 27%and 42% forthe family compared with the electricity-kerosene combined usage and the all-electric usages with and without nighttime electric power respectively. Further it has been suggested that further reduction of CO2 emission is possible by optimizing the demand balance of hot water and electricity.

  20. Optimization of Electricity Generation Schemes in the Java-Bali Grid System with Co2 Reduction Consideration

    Directory of Open Access Journals (Sweden)

    Farizal Farizal

    2016-08-01

    Full Text Available This research considers the problem of reducing CO2 emissions from the Java-Bali power grid system that consists of a variety of power-generating plants: coal-fired, natural gas, oil, and renewable energy (PV, geothermal, hydroelectric, wind, and landfill gas. The problem is formulated as linear programming and solved using LINGO 10. The model was developed for a nation to meet a specified CO2 emission target. Two carbon dioxide mitigation options are considered in this study, i.e. fuel balancing and fuel switching. In order to reduce the CO2 emissions by 26% in 2021, State Electric Supply Company (PLN has to generate up to 30% of electricity from renewable energy (RE, and the cost of electricity (COE is expected to increase to 617.77 IDR per kWh for a fuel balancing option, while for fuel switching option, PLN has to generate 29% of electricity from RE, and the COE is expected to increase to 535.85 IDR per kWh.

  1. Photocatalytic Reduction of CO2 by ZnO Micro/nanomaterials with Different Morphologies and Ratios of {0001} Facets

    Science.gov (United States)

    Liu, Xiaodi; Ye, Liqun; Liu, Shanshan; Li, Yinping; Ji, Xiaoxu

    2016-12-01

    ZnO microspheres, ZnO microflowers and ZnO nanorods are successfully synthesized via a convenient solvothermal method in distilled water-ethanol mixed medium. The as-prepared ZnO micro/nanomaterials are characterized by XRD, SEM, TEM, HRTEM, XPS, BET, and UV-Vis. The morphologies and exposed facets of the ZnO micro/nanomaterials can be controlled by simply changing the volume ratio of distilled water to ethanol, and their formation mechanisms are also proposed. In addition, the photocatalytic activities of the ZnO samples are investigated towards the photoreduction of CO2 to CO. It is found that ZnO nanorods with high ratio of {0001} facets and large surface areas possess higher CO formation rate (3.814 μmol g-1 h-1) in comparison with ZnO microspheres and ZnO microflowers (3.357 and 1.627 μmol g-1 h-1, respectively). The results can not only provide an important indication about the influence of the {0001} facets on the activity of CO2 photoreduction over ZnO, but also demonstrate a strategy for tuning the CO2 photoreduction performance by tailoring the surface structures of ZnO micro/nanomaterials.

  2. Self-doped Ti(3+)-TiO2 as a photocatalyst for the reduction of CO2 into a hydrocarbon fuel under visible light irradiation.

    Science.gov (United States)

    Sasan, Koroush; Zuo, Fan; Wang, Yuan; Feng, Pingyun

    2015-08-28

    Self-doped TiO2 shows visible light photocatalytic activity, while commercial TiO2 (P25) is only UV responsive. The incorporation of Ti(3+) into TiO2 structures narrows the band gap (2.90 eV), leading to significantly increased photocatalytic activity for the reduction of CO2 into a renewable hydrocarbon fuel (CH4) in the presence of water vapour under visible light irradiation.

  3. The Reductive Activation of CO2 Across a Ti=Ti Double Bond: Synthetic, Structural, and Mechanistic Studies

    Science.gov (United States)

    2015-01-01

    The reactivity of the bis(pentalene)dititanium double-sandwich compound Ti2Pn†2 (1) (Pn† = 1,4-{SiiPr3}2C8H4) with CO2 is investigated in detail using spectroscopic, X-ray crystallographic, and computational studies. When the CO2 reaction is performed at −78 °C, the 1:1 adduct 4 is formed, and low-temperature spectroscopic measurements are consistent with a CO2 molecule bound symmetrically to the two Ti centers in a μ:η2,η2 binding mode, a structure also indicated by theory. Upon warming to room temperature the coordinated CO2 is quantitatively reduced over a period of minutes to give the bis(oxo)-bridged dimer 2 and the dicarbonyl complex 3. In situ NMR studies indicated that this decomposition proceeds in a stepwise process via monooxo (5) and monocarbonyl (7) double-sandwich complexes, which have been independently synthesized and structurally characterized. 5 is thermally unstable with respect to a μ-O dimer in which the Ti–Ti bond has been cleaved and one pentalene ligand binds in an η8 fashion to each of the formally TiIII centers. The molecular structure of 7 shows a “side-on” bound carbonyl ligand. Bonding of the double-sandwich species Ti2Pn2 (Pn = C8H6) to other fragments has been investigated by density functional theory calculations and fragment analysis, providing insight into the CO2 reaction pathway consistent with the experimentally observed intermediates. A key step in the proposed mechanism is disproportionation of a mono(oxo) di-TiIII species to yield di-TiII and di-TiIV products. 1 forms a structurally characterized, thermally stable CS2 adduct 8 that shows symmetrical binding to the Ti2 unit and supports the formulation of 4. The reaction of 1 with COS forms a thermally unstable complex 9 that undergoes scission to give mono(μ-S) mono(CO) species 10. Ph3PS is an effective sulfur transfer agent for 1, enabling the synthesis of mono(μ-S) complex 11 with a double-sandwich structure and bis(μ-S) dimer 12 in which the Ti

  4. Climate Change and employment. Impact on employment in the European Union-25 of climate change and CO2 emission reduction measures by 2030

    Energy Technology Data Exchange (ETDEWEB)

    Dupressoir, S.; Belen Sanchez, A.; Bobe, P.; Hoefele, V. (and others)

    2007-05-15

    This study was intended provide an analysis of the potential costs and benefits for employment of the policies and measures against climate change as well as of the manifestations of the consequences of climate change in Europe. This report comprises two divisions. The first, entitled 'Impact of climate change', attempts to determine the potential impact on employment in Europe of the consequences of climate change (Part 1). The second, entitled 'Impact of CO2 emission reduction measures', analyses the potential implications for employment of climate-change prevention policies in the EU with time-horizons of 2012 and 2030 (Parts 2 to 4). The conclusions and recommendations of the study appear in four parts : Part 1 analyses the potential consequences for employment of climatic warming in Europe; Part 2 presents the objectives, the hypotheses and the methodology of the 'impact of CO2 emission reduction measures' division; Part 3 analyses the foreseeable effects of CO2 emission reduction measures on employment in Europe; Part 4 offers general (or sector-wide) recommendations for measures and policies to promote positive effects and prevent negative effects. The concluding part discusses the uncertainties and identifies the questions deserving further investigation.

  5. Quantifying co-benefits of source-specific CO2 emission reductions in Canada and the US: An adjoint sensitivity analysis

    Science.gov (United States)

    Zhao, S.; Soltanzadeh, M.; Pappin, A. J.; Hakami, A.; Turner, M. D.; Capps, S.; Henze, D. K.; Percell, P.; Bash, J. O.; Napelenok, S. L.; Pinder, R. W.; Russell, A. G.; Nenes, A.; Baek, J.; Carmichael, G. R.; Stanier, C. O.; Chai, T.; Byun, D.; Fahey, K.; Resler, J.; Mashayekhi, R.

    2016-12-01

    Scenario-based studies evaluate air quality co-benefits by adopting collective measures introduced under a climate policy scenario cannot distinguish between benefits accrued from CO2 reductions among sources of different types and at different locations. Location and sector dependencies are important factors that can be captured in an adjoint-based analysis of CO2 reduction co-benefits. The present study aims to quantify how the ancillary benefits of reducing criteria co-pollutants vary spatially and by sector. The adjoint of USEPA's CMAQ was applied to quantify the health benefits associated with emission reduction of criteria pollutants (NOX) in on-road mobile, Electric Generation Units (EGUs), and other select sectors on a location-by-location basis across the US and Canada. These health benefits are then converted to CO2 emission reduction co-benefits by accounting for source-specific emission rates of criteria pollutants in comparison to CO2. We integrate the results from the adjoint of CMAQ with emission estimates from 2011 NEI at the county level, and point source data from EPA's Air Markets Program Data and National Pollutant Release Inventory (NPRI) for Canada. Our preliminary results show that the monetized health benefits (due to averted chronic mortality) associated with reductions of 1 ton of CO2 emissions is up to 65/ton in Canada and 200/ton in US for mobile on-road sector. For EGU sources, co-benefits are estimated at up to 100/ton and 10/ton for the US and Canada respectively. For Canada, the calculated co-benefits through gaseous pollutants including NOx is larger than those through PM2.5 due to the official association between NO2 exposure and chronic mortality. Calculated co-benefits show a great deal of spatial variability across emission locations for different sectors and sub-sectors. Implications of such spatial variability in devising control policy options that effectively address both climate and air quality objectives will be discussed.

  6. Potential Analysis of Industrial Waste Gas Recycling in CO2 Emission Reduction%工业废气再利用的碳减排潜力分析

    Institute of Scientific and Technical Information of China (English)

    都基峻; 田刚; 谭玉玲; 龙红艳; 张凡; 石应杰

    2015-01-01

    There was significant correlation between China′s industrial waste gas emission and carbon emission, and it is necessary to further study the waste gas emission reduction which is the important approach and key breakthrough point to realize carbon emission reduction.A carbon emission reduction calculation method was set up for the waste heat utilization, the waste pressure utilization and the recycling of waste gas with heat value based on the energy balance principle.The current technologies of waste gas recycling of sintering machine, cement kiln cooperative treatment of domestic wastes and municipal sludge, and exhaust gas cascade utilization of electrolytic aluminum industry to coal-fired power plants were introduced.The corresponding carbon emission reductions by waste gas recycling in these industries were calculated and analyzed.The results showed that the industrial waste gas recycling technologies could reduce emission of waste gas volume and thus reduce emission of CO2 , contributing to almost 25%of the total carbon emission reduction in China.The technologies should play an important role in waste gas emission and CO2 emission reduction, and be the important approach to realize carbon emission reduction target in 2020.Therefore, the development of the waste gas recycling technologies should be strengthened.%中国CO2排放量与工业废气排放量之间具有很高的相关性,废气量减排是实现CO2减排的重要手段和切入点,有必要开展深入研究。根据能量平衡的原理,建立了余热利用、余压利用和含热值气体再利用等碳减排计算方法,简述了现有的钢铁烧结机烟气循环技术、水泥窑协同处理生活垃圾和市政污泥技术以及电解铝烟气阶梯利用于火电厂技术,并对以上主要行业废气再利用的碳减排量进行了计算和分析。结果表明,主要工业行业的废气再利用技术可以减少废气量排放,进而减少CO2排放,对于实现中国CO

  7. Effects of CO2-induced pH reduction on the exoskeleton structure and biophotonic properties of the shrimp Lysmata californica.

    Science.gov (United States)

    Taylor, Jennifer R A; Gilleard, Jasmine M; Allen, Michael C; Deheyn, Dimitri D

    2015-06-01

    The anticipated effects of CO2-induced ocean acidification on marine calcifiers are generally negative, and include dissolution of calcified elements and reduced calcification rates. Such negative effects are not typical of crustaceans for which comparatively little ocean acidification research has been conducted. Crustaceans, however, depend on their calcified exoskeleton for many critical functions. Here, we conducted a short-term study on a common caridean shrimp, Lysmata californica, to determine the effect of CO2-driven reduction in seawater pH on exoskeleton growth, structure, and mineralization and animal cryptic coloration. Shrimp exposed to ambient (7.99 ± 0.04) and reduced pH (7.53 ± 0.06) for 21 days showed no differences in exoskeleton growth (percent increase in carapace length), but the calcium weight percent of their cuticle increased significantly in reduced pH conditions, resulting in a greater Ca:Mg ratio. Cuticle thickness did not change, indicating an increase in the mineral to matrix ratio, which may have mechanical consequences for exoskeleton function. Furthermore, there was a 5-fold decrease in animal transparency, but no change in overall shrimp coloration (red). These results suggest that even short-term exposure to CO2-induced pH reduction can significantly affect exoskeleton mineralization and shrimp biophotonics, with potential impacts on crypsis, physical defense, and predator avoidance.

  8. Mesoporous NiCo2O4 Nanoplates on Three-Dimensional Graphene Foam as an Efficient Electrocatalyst for the Oxygen Reduction Reaction.

    Science.gov (United States)

    Tong, Xili; Chen, Shuai; Guo, Congxiu; Xia, Xinhui; Guo, Xiang-Yun

    2016-01-21

    Catalysts for the oxygen reduction reaction (ORR) are highly important in fuel cells and metal-air batteries. Cheap ORR catalysts with ultrahigh electrochemical activity, selectivity, and stability are extremely desirable but still remain challenging. Herein, mesoporous NiCo2O4 nanoplate (NP) arrays on three-dimensional (3D) graphene foam are shown to be a highly economical ORR catalyst. This mesoporous mixed-valence oxide can provide more electrocatalytic active sites with increased accessible surface area. In addition, graphene-foam-supported NiCo2O4 NP arrays have a 3D hierarchical porous structure, which is of great benefit to ion diffusion and electron transfer. As a result, the mesoporous NiCo2O4 NP arrays/graphene foam catalyst exhibits outstanding ORR performance with the four-electron reduction of O2 to H2O in alkaline media. Furthermore, the mesoporous catalyst shows enhanced electrocatalytic activity with a half-wave potential of 0.86 V vs RHE and better stability compared with a commercial Pt/C catalyst.

  9. Kinetics of Reduction of CaO-FeO x -MgO-PbO-SiO2 Slags by CO-CO2 Gas Mixtures

    Science.gov (United States)

    Jahanshahi, Sharif; Wright, Steven

    2017-08-01

    Kinetics of the reaction of lead slags (PbO-CaO-SiO2-FeO x -MgO) with CO-CO2 gas mixtures was studied by monitoring the changes in the slag composition when a stream of CO-CO2 gas mixture was blown on the surface of thin layers of slags (3 to 10 mm) at temperatures in the range of 1453 K to 1593 K (1180 °C to 1320 °C). These measurements were carried out under conditions where mass transfer in the gas phase was not the rate-limiting step and the reduction rates were insensitive to factors affecting mass transfer in the slag phase. The results show simultaneous reduction of PbO and Fe2O3 in the slag. The measured specific rate of oxygen removal from the melts varied from about 1 × 10-6 to 4 × 10-5 mol O cm-2 s-1 and was strongly dependent on the slag chemistry and its oxidation state, partial pressure of CO in the reaction gas mixture, and temperature. The deduced apparent first-order rate constant increased with increasing iron oxide content, oxidation state of the slag, and temperature. The results indicate that under the employed experimental conditions, the rate of formation of CO2 at the gas-slag interface is likely to be the rate-limiting step.

  10. Strongly visible-light responsive plasmonic shaped AgX:Ag (X = Cl, Br) nanoparticles for reduction of CO2 to methanol.

    Science.gov (United States)

    An, Changhua; Wang, Jizhuang; Jiang, Wen; Zhang, Meiyu; Ming, Xijuan; Wang, Shutao; Zhang, Qinhui

    2012-09-21

    Plasmonic shaped AgX:Ag (X = Cl, Br) nanoparticles have been synthesized by a facile and versatile glycerol-mediated solution route. The as-prepared AgX:Ag nanoparticles exhibit regular shapes, i.e., cube-tetrapod-like AgCl:Ag nanoparticles and AgBr:Ag nanoplates. Compared with the pristine AgX, AgX:Ag nanocomposites display stronger absorption in the visible region due to the surface plasmon resonance of silver nanoparticles. The calculation of bandgaps and band positions indicates the as-achieved AgX:Ag nanoparticles can be used as a class of potential photocatalyst for the reduction of CO(2). For example, reduction of CO(2) under visible light irradiation with the assistance of the anisotropic AgX:Ag nanoparticles yields as much as 100 μmol methanol in the products. Furthermore, the AgX:Ag nanoparticles can maintain its structure and activity after 3 runs of reactions. Therefore, the present route opens an avenue to acquire plasmonic photocatalysts for conversion of CO(2) into useful organic compounds.

  11. Enhanced Photocatalytic Reduction of CO2 to CO through TiO2 Passivation of InP in Ionic Liquids.

    Science.gov (United States)

    Zeng, Guangtong; Qiu, Jing; Hou, Bingya; Shi, Haotian; Lin, Yongjing; Hettick, Mark; Javey, Ali; Cronin, Stephen B

    2015-09-21

    A robust and reliable method for improving the photocatalytic performance of InP, which is one of the best known materials for solar photoconversion (i.e., solar cells). In this article, we report substantial improvements (up to 18×) in the photocatalytic yields for CO2 reduction to CO through the surface passivation of InP with TiO2 deposited by atomic layer deposition (ALD). Here, the main mechanisms of enhancement are the introduction of catalytically active sites and the formation of a pn-junction. Photoelectrochemical reactions were carried out in a nonaqueous solution consisting of ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM]BF4), dissolved in acetonitrile, which enables CO2 reduction with a Faradaic efficiency of 99% at an underpotential of +0.78 V. While the photocatalytic yield increases with the addition of the TiO2 layer, a corresponding drop in the photoluminescence intensity indicates the presence of catalytically active sites, which cause an increase in the electron-hole pair recombination rate. NMR spectra show that the [EMIM](+) ions in solution form an intermediate complex with CO2(-), thus lowering the energy barrier of this reaction.

  12. Theoretical Insights into the Impact of Ru Catalyst Anchors on the Efficiency of Photocatalytic CO2 Reduction on Ta2O5.

    Science.gov (United States)

    Akimov, Alexey V; Jinnouchi, R; Shirai, S; Asahi, R; Prezhdo, Oleg V

    2015-06-18

    We present a computational study of the dynamical and electronic structure origins of the impact of anchoring groups, PO3H2, COOH, and OH, on the efficiency of photochemical CO2 reduction in Ru(di-X-bpy)(CO)2Cl2/Ta2O5 systems. Recent experimental studies indicate that the efficiency may not directly correlate with the driving force for electron transfer (ET) in these systems, prompting the need for further investigation of the role of anchor groups. Our analysis shows that there are at least two key roles of the anchor in determining the efficiency of CO2 reduction by the Ru complex. First, depending on local steric interactions, different tilting angles and their fluctuations may emerge for different anchors, affecting the magnitude of the donor-acceptor coupling. Second, depending on localization of acceptor states on the anchor, determined by the anchor's tendency to form conjugate subsystems, the yields of ET to the catalytic center may vary, directly affecting the photocatalytic efficiency. Finally, our calculations indicate that surface modeling with N-doping and many-body effects are needed to describe the ET process in the systems properly. N-doping imparts the Ta2O5 surface with a dipole moment, while Coulomb and exchange contributions to the electron-hole interaction can produce excitons that should be taken into account.

  13. Increased Use of Natural Gas for Power Generation in the U.S. and the Resulting Reductions in Emissions of CO2, NOx and SO2

    Science.gov (United States)

    De Gouw, J. A.; Parrish, D. D.; Trainer, M.

    2013-12-01

    Over the past decades, natural gas has increasingly replaced coal as a fuel for electrical power generation in the U.S. As a result, there have been significant reductions in the emissions of carbon dioxide (CO2), nitrogen oxides (NOx) and sulfur dioxide (SO2). Power plant emissions are continuously measured at the stack using continuous emissions monitoring systems (CEMS) required by the EPA. Previous studies using airborne measurements have shown these CEMS measurements to be accurate. Here, we use annual emissions since 1995 from all point sources included in the CEMS database to quantify the changes in CO2, NOx and SO2 emissions that have resulted from the changing use of fuels and technologies for power generation. In 1997, 83% of electrical power in the CEMS database was generated from coal-fired power plants. In 2012, the contribution from coal had decreased to 59%, and natural gas contributed 34% of the electrical power. Natural gas-fired power plants, in particular those equipped with combined cycle technology, emit less than 50% of CO2 per kWh produced compared to coal-fired plants. As a result of the increased use of natural gas, total CO2 emissions from U.S. power plants have decreased since 2008. In addition, natural gas-fired power plants emit less NOx and far less SO2 per kWh produced than coal-fired power plants. The increased use of natural gas has therefore led to significant emissions reductions of NOx and SO2 in addition to those obtained from the implementation of emissions control systems on coal-fired power plants. The increased use of natural gas for power generation has led to significant reductions in CO2 emissions as well as improvements in U.S. air quality. We will illustrate these points with examples from airborne measurements made using the NOAA WP-3D aircraft in the Southeastern U.S. in 2013 as part of the NOAA Southeast Nexus (SENEX) study. The emissions reductions from U.S. power plants due to the increased use of natural gas will

  14. Nitrate reduction during ground-water recharge, Southern High Plains, Texas

    Science.gov (United States)

    Fryar, Alan E.; Macko, Stephen A.; Mullican, William F., III; Romanak, Katherine D.; Bennett, Philip C.

    2000-01-01

    In arid and semi-arid environments, artificial recharge or reuse of wastewater may be desirable for water conservation, but NO 3- contamination of underlying aquifers can result. On the semi-arid Southern High Plains (USA), industrial wastewater, sewage, and feedlot runoff have been retained in dozens of playas, depressions that focus recharge to the regionally important High Plains (Ogallala) aquifer. Analyses of ground water, playa-basin core extracts, and soil gas in an 860-km 2 area of Texas suggest that reduction during recharge limits NO 3- loading to ground water. Tritium and Cl - concentrations in ground water corroborate prior findings of focused recharge through playas and ditches. Typical δ15N values in ground water (>12.5‰) and correlations between δ15N and ln CNO -3-N suggest denitrification, but O 2 concentrations ≥3.24 mg l -1 indicate that NO 3- reduction in ground water is unlikely. The presence of denitrifying and NO 3--respiring bacteria in cores, typical soil-gas δ15N values water can still exceed drinking-water standards, as observed in the vicinity of one playa that received wastewater. Therefore, continued ground-water monitoring in the vicinity of other such basins is warranted.

  15. CO2减排及封存利用技术概况及发展%General Sitiation and Development of Discharge-Reduction and Sealing-up-Utilization Technology of CO2

    Institute of Scientific and Technical Information of China (English)

    李现勇

    2008-01-01

    减缓以至最终控制能源生产利用过程中CO2的排放量,是全球能源生产面临的重大挑战.文章从提高能源利用效率和转化效率以及CO2的捕集、分离和利用两个方面介绍了国内外CO2减排技术,如洗煤技术、高效清洁煤技术等,以及分离捕集CO2、封存利用CO2的各种方法.对CO2减排技术的发展方向还作了探讨.

  16. Reduction of CO2 emission from transportation activities in the area of Pasar Besar in Malang City

    Science.gov (United States)

    Sari, K. E.; Sulistyo, D. E.; Utomo, D. M.

    2017-06-01

    The number of vehicles increases every year. Where vehicles are the largest contributor to air pollution up to 70%-80%, while 20%-30% caused by industrial activities. The increasing number of vehicles which perform movements will result in more emissions of vehicles in the free air of the city. Traffic is also influenced by the presence of land use. One of the types of land use that have considerable influence against the movement of traffic is trade. Along with the development of transport activities in the area of Pasar Besar Malang city (the Biggest Traditional Market in Malang), it will cause problems such as traffic jam and air pollution. Therefore, the need for proper handling of the problem of traffic jam and air pollution in the area of Pasar Besar that is to identify the performance of road traffic around area of Pasar Besar and calculate the quantity of CO2 emissions based on the footprint of transport on the area of Pasar Besar. Where is produced that level of service roads on its way around area of Pasar Besar have an average value between LOS A and B, while the quantity of CO2 emissions is based on the footprint of transport on area of Pasar Besar that is amounting to 4,551.42 tons/year. The magnitude of the emissions have exceeded the standard of composition in the air so that the need for recommendations. Recommendations in this research is in the form of simulated users of private vehicle redirects to public transportation based on the level of willingness to switch by the users of private vehicles. The selected simulation that is the second of four simulations with the output of emissions amounting to 3,952.91 tons/year in which can reduce emissions amounting to 598.51 tons/year or approximately 13.15%.

  17. An Estimation of Reduction of the Primary Energy and the CO2 Emission in Residential PEFC Co-Generation System with Li-ion Battery Modules

    Science.gov (United States)

    Maeda, Kazushige; Yonemori, Hideto; Yasaka, Yasuyoshi

    This paper presents the effects of introduction of residential polymer electrolyte fuel cell (PEFC) co-generation system with batteries in comparison with conventional systems that consist of a gas boiler and electric power from commercial grid, by computer simulation. The PEFC co-generation system in commercial use provides the average primary energy saving rate of 12.7% and CO2 reduction rate of 15.4% with respect to the conventional system. Addition of 8.0-kWh batteries to the PEFC system results in limited improvements of 0.8 points and 0.9 points in the reduction rates, respectively, yielding 13.5% and 16.3%, when using a conventional operation planning method. A new operation planning method is proposed in order to make a precise control of charging and discharging the batteries. The average primary energy saving rate reaches up to 16.9% by the improvement of 4.2 points, and CO2 reduction rate reaches up to 20.4% by the improvement of 5.0 points in the PEFC co-generation system with 8.0-kWh batteries using the new operation planning method. The new method can thus realize a substantial improvement in reduction rates. Furthermore, it is shown that the suitable battery module capacity for the residential PEFC co-generation system is 4.0kWh.

  18. CO2 Emission Reduction and Its Utilization Applied in Indirect Coal Liquefaction Project%煤间接液化项目中CO2的减排及利用

    Institute of Scientific and Technical Information of China (English)

    李俊诚; 李龙; 刘万洲; 金嘉璐; 赵金立

    2012-01-01

    The CO2 emitted from large CTL (Coal to Liquid) Projects is high in purity and intensive. Through selection of advanced process technologies, reasonable optimization of processes and use of the heat and the high heat-value tail gas, not only the energy efficiency can be improved, coal consumption reduced, but also the CO2 emission can be reduced. In addition, based on the identification of the CO2 emission sources, its load and concentration, reasonable use of CO2 was identified. Then an economic evaluation model of CO2 from the CTL project applied in EOR (Enhance Oil Recovery) was built to prove its economic feasibility.%针对大型煤炭间接液化项目中CO2纯度高、排放集中的特点,通过技术选择、工艺优化和对工艺过程中产生的余热和高热值尾气进行充分利用,可大幅减少CO2排放.通过对CO2排放源进行识别,有针对性地确定其合理的利用方式;通过建立煤炭间接液化工厂排放CO2用于驱油的经济评价模型,对其应用经济可行性进行了论证.

  19. Dynamic photocatalytic reduction of CO2 to CO in a honeycomb monolith reactor loaded with Cu and N doped TiO2 nanocatalysts

    Science.gov (United States)

    Tahir, Muhammad; Tahir, Beenish

    2016-07-01

    Cordierite honeycomb monoliths loaded with N/TiO2 and Cu/TiO2 nanocatalysts for dynamic photocatalytic CO2 reduction with H2 to CO in a continuous photoreactor illuminated with UV-light irradiations have been investigated. The nanocatalysts, loaded over the monoliths channels using sol-gel dip-coating method, were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), N2 adsorption-desorption, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance and photoluminescence (PL) analysis. Crystalline and anatase TiO2 structure with nanoparticles evenly supported over the cordierite monolith channels were observed. Cu and N presented over TiO2, shifted band gap energy towards visible region and hindered charges recombination rate. Loading Cu and N greatly improved TiO2 photoactivity for dynamic CO2 reduction to CO. Due to high photoactivity and selectivity, Cu/TiO2 assisted system yielded 14 times higher CO than the N/TiO2 and 64 times the amount of copper observed over pure TiO2 in a continuous operation of photoreactor. This significant improvement in Cu/TiO2 activity was noticeable due to efficient trapping and transport of electrons by Cu-metal. With unique properties, N/TiO2 showed good activity for continuous CO2 reduction to CH4. In addition, a photocatalytic reaction mechanism is proposed to understand the experimental results over Cu and N modified TiO2 catalysts in a continuous operation of photoreactor.

  20. Estimation of CO2 reduction by parallel hard-type power hybridization for gasoline and diesel vehicles.

    Science.gov (United States)

    Oh, Yunjung; Park, Junhong; Lee, Jong Tae; Seo, Jigu; Park, Sungwook

    2017-10-01

    The purpose of this study is to investigate possible improvements in ICEVs by implementing fuzzy logic-based parallel hard-type power hybrid systems. Two types of conventional ICEVs (gasoline and diesel) and two types of HEVs (gasoline-electric, diesel electric) were generated using vehicle and powertrain simulation tools and a Matlab-Simulink application programming interface. For gasoline and gasoline-electric HEV vehicles, the prediction accuracy for four types of LDV models was validated by conducting comparative analysis with the chassis dynamometer and OBD test data. The predicted results show strong correlation with the test data. The operating points of internal combustion engines and electric motors are well controlled in the high efficiency region and battery SOC was well controlled within ±1.6%. However, for diesel vehicles, we generated virtual diesel-electric HEV vehicle because there is no available vehicles with similar engine and vehicle specifications with ICE vehicle. Using a fuzzy logic-based parallel hybrid system in conventional ICEVs demonstrated that HEVs showed superior performance in terms of fuel consumption and CO2 emission in most driving modes. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Honeycomb Cupric Oxide and Hematite Nanotubes Synergism Photoelectro-reduction CO2%蜂窝状CuO和Fe2O3纳米管协同光电还原CO2

    Institute of Scientific and Technical Information of China (English)

    王祜英; 徐金凤; 井华; 张军; 李培强; 路福绥

    2013-01-01

    annealed under oxygen atmosphere with the flow rate of 60 sccm then heated to 300 ℃ with the rate of 3 ℃.min-1 and maintained at 300 ℃ for 2 h.Then cooled to room temperature with the rate of 3 ℃.min-1.Then the CuO HCs/Fe2O3 NTs catalysis was obtained.The SEM images showed that CuO HCs distributed uniformly on the surface of Fe2O3 NTs that arranged in order were volcano-like.Measured by UV-vis DRS (ultraviolet-visible diffuse reflection spectrum) and valence band photoemission spectrum,its band energy has been narrowed from 2.03 eV to 1.84 eV after CuO decorating.It also has admirable photocatalytic and electrocatalytic reduction performance.The main product of photoelectrocatalytic CO2 reduction identified by chromatography was methanol and its concentration reached 3.77 mmol/L after 6 h.The study has some guidance and reference significance for photoelectrocatalytic CO2 reduction.

  2. Effects on CO2 Reduction Potential of the Accelerated Introduction of Plug-in Hybrid Electric Vehicle in the Market

    Science.gov (United States)

    Shinoda, Yukio; Yabe, Kuniaki; Tanaka, Hideo; Akisawa, Atsushi; Kashiwagi, Takao

    In this paper we consider that there are two economical social behaviors when new technologies are introduced. One is on the short-term economic basis, the other one is on the long-tem economic basis. If we consider a learning curve on the technology, it is more economical than short-term behavior to accelerate the introduction of the technology much wider in the earlier term than that on short-term economic basis. The costs in the accelerated term are higher, but the introduction costs in the later terms are cheaper by learning curve. This paper focuses on the plug-in hybrid electric vehicles (PHEVs). The ways to derive the results on short-term economic basis and the results on long-term economic basis are shown. The result of short-term behaviors can be derived by using the iteration method in which the battery costs in every term are adjusted to the learning curve. The result of long-term behaviors can be derived by seeking to the way where the amount of battery capacity is increased. We also estimate that how much subsidy does it need to get close to results on the long-term economic basis when social behavior is on the short-term economic basis. We assume subsidy for PHEV's initial costs, which can be financed by charging fee on petroleum consumption. In that case, there is no additional cost in the system. We show that the greater the total amount of money to that subsidy is, the less the amount of both CO2 emissions and system costs.

  3. Synthesis, characterization and enhanced photocatalytic CO2 reduction activity of graphene supported TiO2 nanocrystals with coexposed {001} and {101} facets.

    Science.gov (United States)

    Xiong, Zhuo; Luo, Ying; Zhao, Yongchun; Zhang, Junying; Zheng, Chuguang; Wu, Jeffrey C S

    2016-05-11

    It is known that the combination of TiO2 and graphene and the control of TiO2 crystal facets are both effective routes to improve the photocatalytic performance of TiO2. Here, we report the synthesis and the photocatalytic CO2 reduction performance of graphene supported TiO2 nanocrystals with coexposed {001} and {101} facets (G/TiO2-001/101). The combination of TiO2 and graphene enhanced the crystallinity of TiO2 single nanocrystals and obviously improved their dispersion on graphene. The "surface heterojunction" formed by the coexposed {001} and {101} facets can promote the spatial separation of photogenerated electrons and holes toward different facets and the supports of graphene can further enhance the separation through accelerated electron migration from TiO2 to graphene. The G/TiO2-001/101 exhibited high photocatalytic CO2-reduction activity with a maximum CO yield reaching 70.8 μmol g(-1) h(-1). The enhanced photocatalytic activity of the composites can be attributed to their high surface area, good dispersion of TiO2 nanoparticles, and effective separation of excited charges due to the synergy of graphene supports and the co-exposure of {001} and {101} facets.

  4. Photocatalytic CO2 reduction over B4C/C3N4 with internal electric field under visible light irradiation.

    Science.gov (United States)

    Zhang, Xiaojie; Wang, Lei; Du, Quanchao; Wang, Zhiyong; Ma, Shuguo; Yu, Miao

    2016-02-15

    Boron carbide/graphitic carbon nitride (B4C/g-C3N4) p-n hetero-junction photocatalyst with an internal electric field was synthesized by a facile solvent evaporation method and characterized by field emission scanning electron microscope (FESEM), UV-Vis diffuse reflectance spectra (UV-Vis DRS), photoluminescence spectra (PL), etc. Photocatalytic activity of the composite B4C/g-C3N4 loaded with Pt co-catalyst was evaluated using CO2 conversion to CH4 with H2 as the hydrogen source and reductant under visible light irradiation. The coupling of p-type B4C with n-type g-C3N4 significantly improved the performance of photocatalytic CO2 reduction; with the optimum B4C mass fraction of 1/6, the composite photocatalyst showed approximately 6 and 8 times higher CH4 generation rate than g-C3N4 and B4C, respectively. The enhancement was attributed to efficient photo-excited electron/hole separation due to the formation of internal electric field at the p-B4C/n-C3N4 interface.

  5. Self-doped Ti3+-TiO2 as a photocatalyst for the reduction of CO2 into a hydrocarbon fuel under visible light irradiation

    Science.gov (United States)

    Sasan, Koroush; Zuo, Fan; Wang, Yuan; Feng, Pingyun

    2015-08-01

    Self-doped TiO2 shows visible light photocatalytic activity, while commercial TiO2 (P25) is only UV responsive. The incorporation of Ti3+ into TiO2 structures narrows the band gap (2.90 eV), leading to significantly increased photocatalytic activity for the reduction of CO2 into a renewable hydrocarbon fuel (CH4) in the presence of water vapour under visible light irradiation.Self-doped TiO2 shows visible light photocatalytic activity, while commercial TiO2 (P25) is only UV responsive. The incorporation of Ti3+ into TiO2 structures narrows the band gap (2.90 eV), leading to significantly increased photocatalytic activity for the reduction of CO2 into a renewable hydrocarbon fuel (CH4) in the presence of water vapour under visible light irradiation. Electronic supplementary information (ESI) available: Experimental details, XPS, XRD and SEM images. See DOI: 10.1039/c5nr02974k

  6. Solar irradiance reduction to counteract radiative forcing from a quadrupling of CO2: climate responses simulated by four earth system models

    Directory of Open Access Journals (Sweden)

    M. Lawrence

    2012-06-01

    Full Text Available In this study we compare the response of four state-of-the-art Earth system models to climate engineering under scenario G1 of two model intercomparison projects: GeoMIP (Geoengineering Model Intercomparison Project and IMPLICC (EU project "Implications and risks of engineering solar radiation to limit climate change". In G1, the radiative forcing from an instantaneous quadrupling of the CO2 concentration, starting from the preindustrial level, is balanced by a reduction of the solar constant. Model responses to the two counteracting forcings in G1 are compared to the preindustrial climate in terms of global means and regional patterns and their robustness. While the global mean surface air temperature in G1 remains almost unchanged compared to the control simulation, the meridional temperature gradient is reduced in all models. Another robust response is the global reduction of precipitation with strong effects in particular over North and South America and northern Eurasia. In comparison to the climate response to a quadrupling of CO2 alone, the temperature responses are small in experiment G1. Precipitation responses are, however, in many regions of comparable magnitude but globally of opposite sign.

  7. Reduction of CO2 to low carbon alcohols on CuO FCs/Fe2O3 NTs catalyst with photoelectric dual catalytic interfaces.

    Science.gov (United States)

    Li, Peiqiang; Wang, Huying; Xu, Jinfeng; Jing, Hua; Zhang, Jun; Han, Haixiang; Lu, Fusui

    2013-12-01

    In this paper, the CuO FCs/Fe2O3 NTs catalyst was obtained after Fe2O3 nanotubes (Fe2O3 NTs) were decorated with CuO flower clusters (CuO FCs) by the pulse electrochemical deposition method. The in situ vertically aligned Fe2O3 NTs were prepared on the ferrous substrate by a potentiostatic anodization method. The SEM result showed the volcano-like Fe2O3 NTs were arranged in order and the CuO FCs constituted of flaky CuO distributed on the Fe2O3 NTs surface uniformly. After CuO FCs were loaded on Fe2O3 NTs, the absorption of visible light was enhanced noticeably, and its band gap narrowed to 1.78 eV from 2.03 eV. The conduction band and valence band locating at -0.73 eV and 1.05 eV, respectively were further obtained. In the PEC reduction of CO2 process, methanol and ethanol were two major products identified by chromatography. Their contents reached 1.00 mmol L(-1) cm(-2) and 107.38 μmol L(-1) cm(-2) after 6 h, respectively. This high-efficiency catalyst with photoelectric dual catalytic interfaces has a great guidance and reference significance for CO2 reduction to liquid carbon fuels.

  8. Impact of Overlapping Fe/TiO2 Prepared by Sol-Gel and Dip-Coating Process on CO2 Reduction

    Directory of Open Access Journals (Sweden)

    Akira Nishimura

    2016-01-01

    Full Text Available Fe-doped TiO2 (Fe/TiO2 film photocatalyst was prepared by sol-gel and dip-coating process to extend its photoresponsivity to the visible spectrum. To promote the CO2 reduction performance with the photocatalyst, some types of base materials used for coating Fe/TiO2, which were netlike glass fiber and Cu disc, were investigated. The characterization of prepared Fe/TiO2 film coated on netlike glass fiber and Cu disc was analyzed by SEM and EPMA. In addition, the CO2 reduction performance of Fe/TiO2 film coated on netlike glass disc, Cu disc, and their overlap was tested under a Xe lamp with or without ultraviolet (UV light, respectively. The results show that the concentration of produced CO increases by Fe doping irrespective of base material used under the illumination condition with UV light as well as that without UV light. Since the electron transfer between two overlapped photocatalysts is promoted, the peak concentration of CO for the Fe/TiO2 double overlapping is approximately 1.5 times as large as the Fe/TiO2 single overlapping under the illumination condition with UV light, while the promotion ratio is approximately 1.1 times under that without UV light.

  9. SrTiO3的合成及其光催化还原CO2的性能%Synthesis of SrTiO3and its performance in photocatalytic reduction of CO2

    Institute of Scientific and Technical Information of China (English)

    尹晓红; 董虹志; 李会亮; 秦士跃; 隋丹丹

    2012-01-01

    In this paper,a perovskite type of Ag/SrTiO3 was prepared hydrothermally and used for photocatalytic reduction of C02 in methanol under illumination of UV light The loaded nanoparticles of Ag decreased the recombination probability of electron-hole pairs and increased the photocatalytic activity. The effects of loaded amount of Ag, loading procedure and surfactant on their catalytic activities were found. After combining the SEM.TEM and HRTEM analysis on morphology and the particle size,as well as the UV-vis measurement on irritation characteristics of the catalysts,we obtained an optimal catalyst of 5wt% Ag/SrTiO3with higher catalytic activity by a one step hydrothermal method.%本文采用水热合成法制备钙钛矿型半导体光催化剂钛酸锶,紫外光激发下,在甲醇溶液中还原CO2制得甲酸甲酯,并通过负载Ag降低了电子与空穴的复合几率,有效地提高了光催化活性.同时,发现了Ag的负载量、负载方法以及表面活性剂对光催化活性的影响规律.借助XRD分析了催化剂的晶型并计算出颗粒的粒径,SEM、TEM、HRTEM观测了催化剂颗粒的形貌,UV-vis吸收光谱检测了其光激发特性.最终,获得了一步水热法制备Ag含量为5wt%的Ag/SrTiO3具有较高催化活性的优化实验结果.

  10. Analysis of Potential Energy Saving and CO2 Emission Reduction of Home Appliances and Commercial Equipments in China

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Nan; Fridley, David; McNeil, Michael; Zheng, Nina; Letschert, Virginie; Ke, Jing

    2011-04-01

    China has implemented a series of minimum energy performance standards (MEPS) for over 30 appliances, voluntary energy efficiency label for 40 products and a mandatory energy information label that covers 19 products to date. However, the impact of these programs and their savings potential has not been evaluated on a consistent basis. This paper uses modeling to estimate the energy saving and CO{sub 2} emission reduction potential of the appliances standard and labeling program for products for which standards are currently in place, under development or those proposed for development in 2010 under three scenarios that differ in the pace and stringency of MEPS development. In addition to a baseline 'Frozen Efficiency' scenario at 2009 MEPS level, the 'Continued Improvement Scenario' (CIS) reflects the likely pace of post-2009 MEPS revisions, and the likely improvement at each revision step. The 'Best Practice Scenario' (BPS) examined the potential of an achievement of international best practice efficiency in broad commercial use today in 2014. This paper concludes that under 'CIS', cumulative electricity consumption could be reduced by 9503 TWh, and annual CO{sub 2} emissions of energy used for all 37 products would be 16% lower than in the frozen efficiency scenario. Under a 'BPS' scenario for a subset of products, cumulative electricity savings would be 5450 TWh and annual CO{sub 2} emissions reduction of energy used for 11 appliances would be 35% lower.

  11. Highly selective and active CO2 reduction electrocatalysts based on cobalt phthalocyanine/carbon nanotube hybrid structures

    Science.gov (United States)

    Zhang, Xing; Wu, Zishan; Zhang, Xiao; Li, Liewu; Li, Yanyan; Xu, Haomin; Li, Xiaoxiao; Yu, Xiaolu; Zhang, Zisheng; Liang, Yongye; Wang, Hailiang

    2017-01-01

    Electrochemical reduction of carbon dioxide with renewable energy is a sustainable way of producing carbon-neutral fuels. However, developing active, selective and stable electrocatalysts is challenging and entails material structure design and tailoring across a range of length scales. Here we report a cobalt-phthalocyanine-based high-performance carbon dioxide reduction electrocatalyst material developed with a combined nanoscale and molecular approach. On the nanoscale, cobalt phthalocyanine (CoPc) molecules are uniformly anchored on carbon nanotubes to afford substantially increased current density, improved selectivity for carbon monoxide, and enhanced durability. On the molecular level, the catalytic performance is further enhanced by introducing cyano groups to the CoPc molecule. The resulting hybrid catalyst exhibits >95% Faradaic efficiency for carbon monoxide production in a wide potential range and extraordinary catalytic activity with a current density of 15.0 mA cm−2 and a turnover frequency of 4.1 s−1 at the overpotential of 0.52 V in a near-neutral aqueous solution. PMID:28272403

  12. Highly selective and active CO2 reduction electrocatalysts based on cobalt phthalocyanine/carbon nanotube hybrid structures

    Science.gov (United States)

    Zhang, Xing; Wu, Zishan; Zhang, Xiao; Li, Liewu; Li, Yanyan; Xu, Haomin; Li, Xiaoxiao; Yu, Xiaolu; Zhang, Zisheng; Liang, Yongye; Wang, Hailiang

    2017-03-01

    Electrochemical reduction of carbon dioxide with renewable energy is a sustainable way of producing carbon-neutral fuels. However, developing active, selective and stable electrocatalysts is challenging and entails material structure design and tailoring across a range of length scales. Here we report a cobalt-phthalocyanine-based high-performance carbon dioxide reduction electrocatalyst material developed with a combined nanoscale and molecular approach. On the nanoscale, cobalt phthalocyanine (CoPc) molecules are uniformly anchored on carbon nanotubes to afford substantially increased current density, improved selectivity for carbon monoxide, and enhanced durability. On the molecular level, the catalytic performance is further enhanced by introducing cyano groups to the CoPc molecule. The resulting hybrid catalyst exhibits >95% Faradaic efficiency for carbon monoxide production in a wide potential range and extraordinary catalytic activity with a current density of 15.0 mA cm-2 and a turnover frequency of 4.1 s-1 at the overpotential of 0.52 V in a near-neutral aqueous solution.

  13. Analysis of Potential Energy Saving and CO2 Emission Reduction of Home Appliances and Commercial Equipments in China

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Nan; Fridley, David; McNeil, Michael; Zheng, Nina; Letschert, Virginie; Ke, Jing

    2011-04-01

    China has implemented a series of minimum energy performance standards (MEPS) for over 30 appliances, voluntary energy efficiency label for 40 products and a mandatory energy information label that covers 19 products to date. However, the impact of these programs and their savings potential has not been evaluated on a consistent basis. This paper uses modeling to estimate the energy saving and CO{sub 2} emission reduction potential of the appliances standard and labeling program for products for which standards are currently in place, under development or those proposed for development in 2010 under three scenarios that differ in the pace and stringency of MEPS development. In addition to a baseline 'Frozen Efficiency' scenario at 2009 MEPS level, the 'Continued Improvement Scenario' (CIS) reflects the likely pace of post-2009 MEPS revisions, and the likely improvement at each revision step. The 'Best Practice Scenario' (BPS) examined the potential of an achievement of international best practice efficiency in broad commercial use today in 2014. This paper concludes that under 'CIS', cumulative electricity consumption could be reduced by 9503 TWh, and annual CO{sub 2} emissions of energy used for all 37 products would be 16% lower than in the frozen efficiency scenario. Under a 'BPS' scenario for a subset of products, cumulative electricity savings would be 5450 TWh and annual CO{sub 2} emissions reduction of energy used for 11 appliances would be 35% lower.

  14. THE POSSIBILITIES OF CO2 EMISSION REDUCTION IN THE PROCESS OF STEEL CHARGE HEATING THROUGH THE SELECTION OF HEATING RATE

    Directory of Open Access Journals (Sweden)

    Barbara Halusiak

    2015-08-01

    Full Text Available The reduction of carbon dioxide emission is an important aspect of the economic policy of each country. Institutions promoting environmental protection seek to reduce the level of greenhouse gas emissions. One of the main emitters of harmful gases to the atmosphere is the steelmaking sector. The heating technology used in metallurgical works contributes to the amount of emitted carbon dioxide that forms as a result of the loss of steel and the combustion of fuel, whose thermal energy is used during the course of the charge heating process in the heating furnace. Achieving the imposed ecological targets by not exceeding the specified emission level is possible by implementing appropriate pollutant emission reducing technologies in the metallurgical industry. Based on numerical computation results, the effect of heating rate on the emission of carbon dioxide has been determined in the paper. This study demonstrates that by selecting the appropriate steel charge heating technology the emissions of greenhouse gases can be substantially reduced.

  15. Analysis of Potential Energy Saving and CO2 Emission Reduction of Home Appliances and Commercial Equipments in China

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Nan; Fridley, David; McNeill, Michael; Zheng, Nina; Letschert, Virginie; Ke, Jing; Saheb, Yamina

    2010-06-07

    China is now the world's largest producer and consumer of household appliances and commercial equipment. To address the growth of electricity use of the appliances, China has implemented a series of minimum energy performance standards (MEPS) for 30 appliances, and voluntary energy efficiency label for 40 products. Further, in 2005, China started a mandatory energy information label that covers 19 products to date. However, the impact of these standard and labeling programs and their savings potential has not been evaluated on a consistent basis. This research involved modeling to estimate the energy saving and CO{sub 2} emission reduction potential of the appliances standard and labeling program for products for which standards are currently in place, or under development and those proposed for development in 2010. Two scenarios that have been developed differ primarily in the pace and stringency of MEPS development. The 'Continued Improvement Scenario' (CIS) reflects the likely pace of post-2009 MEPS revisions, and the likely improvement at each revision step considering the technical limitation of the technology. The 'Best Practice Scenario' (BPS) examined the potential of an achievement of international best practice MEPS in 2014. This paper concludes that under the 'CIS' of regularly scheduled MEPS revisions to 2030, cumulative electricity consumption could be reduced by 9503 TWh, and annual CO{sub 2} emissions would be 16% lower than in the frozen efficiency scenario. Under a 'BPS' scenario for a subset of products, cumulative electricity savings would be 5450 TWh and annual CO{sub 2} emissions reduction would be 35% lower than in the frozen scenario.

  16. Analysis of Potential Energy Saving and CO2 Emission Reduction of Home Appliances and Commercial Equipments in China

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Nan; Fridley, David; McNeill, Michael; Zheng, Nina; Letschert, Virginie; Ke, Jing; Saheb, Yamina

    2010-06-07

    China is now the world's largest producer and consumer of household appliances and commercial equipment. To address the growth of electricity use of the appliances, China has implemented a series of minimum energy performance standards (MEPS) for 30 appliances, and voluntary energy efficiency label for 40 products. Further, in 2005, China started a mandatory energy information label that covers 19 products to date. However, the impact of these standard and labeling programs and their savings potential has not been evaluated on a consistent basis. This research involved modeling to estimate the energy saving and CO{sub 2} emission reduction potential of the appliances standard and labeling program for products for which standards are currently in place, or under development and those proposed for development in 2010. Two scenarios that have been developed differ primarily in the pace and stringency of MEPS development. The 'Continued Improvement Scenario' (CIS) reflects the likely pace of post-2009 MEPS revisions, and the likely improvement at each revision step considering the technical limitation of the technology. The 'Best Practice Scenario' (BPS) examined the potential of an achievement of international best practice MEPS in 2014. This paper concludes that under the 'CIS' of regularly scheduled MEPS revisions to 2030, cumulative electricity consumption could be reduced by 9503 TWh, and annual CO{sub 2} emissions would be 16% lower than in the frozen efficiency scenario. Under a 'BPS' scenario for a subset of products, cumulative electricity savings would be 5450 TWh and annual CO{sub 2} emissions reduction would be 35% lower than in the frozen scenario.

  17. Experimental and Modeling Study on de-NOx Characteristics of Selective Non-catalytic Reduction in O2/CO2 Atmosphere

    Institute of Scientific and Technical Information of China (English)

    Hui Li; Kuihua Han⁎; Hongtao Liu; Chunmei Lu

    2014-01-01

    An experimental study of thermal de-NOx using NH3 as reductant in O2/CO2 atmosphere with the effect of SO2 and different additives was performed in a drop tube furnace. Results show that the optimum temperature win-dow is 841-1184 °C, and the optimum reaction temperature is about 900 °C with a de-NOx efficiency of 95.4%. A certain amount of SO2 has an inhibiting effect on NO reduction. The effect of additives, including Na2CO3, C2H5OH and FeCl3, on NO reduction by NH3 is also explored. The addition of Na2CO3 and FeCl3 is useful to widen the tem-perature window and shift the reaction to lower temperature for the efficiency is increased from 30.5%to 74.0%and 67.4%respectively at 800 °C. Qualitatively, the modeling results using a detailed kinetic modeling mecha-nism represent well most of the process features. The effect of Na2CO3, C2H5OH and FeCl3 addition can be reproduced well by the Na2CO3, C2H5OH and Fe(CO)5 sub-mechanism respectively. The reaction mechanism analysis shows that the effects of these additives on NO reduction are achieved mainly by promoting the produc-tion of OH radicals at lower temperature.

  18. Preparation of CdS@CeO2 core/shell composite for photocatalytic reduction of CO2 under visible-light irradiation

    Science.gov (United States)

    Ijaz, Sana; Ehsan, Muhammad Fahad; Ashiq, Muhammad Naeem; Karamat, Nazia; He, Tao

    2016-12-01

    Present work demonstrates fabrication of CdS@CeO2 core/shell composite and its application in the photocatalytic reduction of CO2 under visible-light irradiation (λ ≥ 420 nm). CdS@CeO2 composite has been successfully prepared by two-step chemical method, while CeO2 and CdS have been synthesized by one-step hydrothermal method. X-ray diffraction analysis confirms the formation of fluorite cubic structure of CeO2 and cubic phase of CdS. High resolution transmission electron microscopy and scanning electron microscopy reveal the microsphere morphology of CdS, while CeO2 (shell) is in the form of spherical particles that surround the CdS (core) in case of the composite. X-ray photoelectron spectroscopy has been used to confirm the composition, oxidation state of the elements and valance band of the obtained materials. The CdS@CeO2 core/shell composite and CdS can convert CO2 into methane and methanol under visible-light irradiation. The CdS@CeO2 composite shows higher yield for both methane and methanol than CdS due to low recombination rate of photogenerated electron/hole pairs, as well as a larger BET specific surface area. Moreover, the CdS@CeO2 core/shell composite also shows improved stability upon photocatalysis.

  19. Facile synthesis of highly active reduced graphene oxide-CuI catalyst through a simple combustion method for photocatalytic reduction of CO2 to methanol

    Science.gov (United States)

    Zhang, Wenjun; Li, Yingjie; Zhang, Xiaoxiong; Li, Cuiluo

    2017-09-01

    We report a facile combustion method synthesis of reduced graphene oxide/CuI composites as a photocatalyst, in which CuI nanoparticles were homogeneously distributed on the surface of reduced graphene oxide (rGO), showing a good visible light response. The rGO-supported and unsupported CuI hybrids were tested over the photocatalytic reduction of CO2 for methanol evolution in visible light. In the current study rGO-CuI composites have shown excellent yields (19.91 μmol g-cat-1). rGO provides a light-weight, charge complementary and two-dimensional material that interacts effectively with the CuI nanoparticles.

  20. Analysis of influencing factors and reduction measures of CO2 emissions in integrated steel works%钢铁联合企业CO2排放影响因素与减排措施分析

    Institute of Scientific and Technical Information of China (English)

    刘颖昊; 刘涛; 丁晓; 黄志甲

    2009-01-01

    以某钢铁联合企业的产品生命周期清单模型为平台,同时利用Tornado Chart工具,计算得到对企业CO2排放影响较大的因素,然后分析得到此种结果的原因,提出相应的减排措施.结果表明:转炉流程对于钢铁企业的影响要大于电炉流程;对该企业CO2排放有重大影响和相关影响的因素是高炉煤气(BFG)的CO2排放系数,炼钢的铁水比和连铸的钢水单耗.相应的可以采取脱除BFG中CO2,降低炼钢的铁水比和优化产品结构选取环境负荷小的生产线等措施.

  1. Upgraded biogas from municipal solid waste for natural gas substitution and CO2 reduction--a case study of Austria, Italy, and Spain.

    Science.gov (United States)

    Starr, Katherine; Villalba, Gara; Gabarrell, Xavier

    2015-04-01

    Biogas is rich in methane and can be further purified through biogas upgrading technologies, presenting a viable alternative to natural gas. Landfills and anaerobic digestors treating municipal solid waste are a large source of such biogas. They therefore offer an attractive opportunity to tap into this potential source of natural gas while at the same time minimizing the global warming impact resulting from methane emissions in waste management schemes (WMS) and fossil fuel consumption reduction. This study looks at the current municipal solid waste flows of Spain, Italy, and Austria over one year (2009), in order to determine how much biogas is generated. Then it examines how much natural gas could be substituted by using four different biogas upgrading technologies. Based on current waste generation rates, exploratory but realistic WMS were created for each country in order to maximize biogas production and potential for natural gas substitution. It was found that the potential substitution of natural gas by biogas resulting from the current WMS seems rather insignificant: 0.2% for Austria, 0.6% for Italy and 0.3% for Spain. However, if the WMS is redesigned to maximize biogas production, these figures can increase to 0.7% for Austria, 1% for Italy and 2% for Spain. Furthermore, the potential CO2 reduction as a consequence of capturing the biogas and replacing fossil fuel can result in up to a 93% reduction of the annual national waste greenhouse gas emissions of Spain and Italy.

  2. CO2在[bmim]BF4/[bmim]PF6中的电化学还原研究%Electrochemical reduction of CO2 in binary ionic liquid bmim BF4/ bmim PF6

    Institute of Scientific and Technical Information of China (English)

    毛信表; 任淑鹰; 张寅旭; 马淳安

    2014-01-01

    对离子液体[bmim]BF4和[bmim]PF6进行了二元复配,测定了不同复配比例离子液体的电导率及红外光谱图,研究了CO2在单一离子液体和二元离子液体[bmim] BF4/[bmim] PF6中的电化学还原行为.结果表明,铜电极上,CO2在单一离子液体和二元离子液体中发生不可逆的电化学还原反应,生成物为CO1-,通过调节[bmim]BF4/[bmim]PF6的体积比,得到了性能较好的二元离子液体,对CO2的电化学还原有显著促进作用.

  3. Contribution to Conversion of CO2 to fuel by electro-photo-catalytic reduction in hydro-genocarbonated aqueous solution tion

    Science.gov (United States)

    Nezzal, Ghania; Benammar, Souad; Hamouni, Samia; Meziane, Dalila; Naama, Sabrina; Abdessemed, Djamel

    2015-04-01

    Referring to the last World Conference COPENHAGEN (2010), endorsed by the United Nations,to '' RISKS OF CLIMATE CHANGES ', states had not reached an agreement to work fairly, in an international program, to limit Carbon dioxide emissions into the atmosphere, to put off it, to the next (in 2015), the right decisions, despite the recommendations of the 'IPCC'. Based on the natural reaction of photosynthesis, which converts carbon dioxide in the presence of water and sun, to '' OSA'' ', it is natural that scientists believe to implement an artificial conversion of CO2 in a renewable energy faster. Our contribution focuses on the same goals, by a different line. In this perspective, nano-materials, catalysts, pervaporation membranes, pervaporation unit, and a photo-reactor prototype, have been made. A summary of the preliminary results presented: For example, are given the concentrations of the various species present in a aqueous solution of sodium hydrogen carbonate, 0.5M, saturated with CO2, at standard temperature and pressure: (CO2) = 1M; (H2CO3) = 0,038M; (HCO3-) = 0,336M; (CO3 --) = 0,34M; pH = 7.33, an overall concentration = 1,714M, more than three times that of the initial solution. It is in such conditions that the conversion of carbon dioxide by the hydrogen produced in situ by electrolysis, in fuel, must be done in the presence of catalyst, under UV radiation. For electrodes, a nano-porous layer was formed on their surface to receive the suitable catalyst. These lats prepared, are made of porous supports (montmorillonite, aluminum and silicon oxides) into which are inserted the metal precursor, by impregnation interactive, in Iron, cobalt, nickel salt solutions, cobalt, nickel. Their performance has been identified by the reduction of para- nitrophenol, to para-aminophenol in aqueous medium in the presence of sodium borohydride. This is the catalyst 'Cobalt supported by SiO2'' that gave the best conversion, 99.5% instead of 99.7%, for a platinum catalyst

  4. Structure, Optical Properties, and Photocatalytic Activity towards H2 Generation and CO2 Reduction of GaN Nanowires via Vapor-Liquid-Solid Process

    Directory of Open Access Journals (Sweden)

    Hong Pang

    2014-01-01

    Full Text Available High quality single crystalline GaN nanowires with large aspect ratio (>100 are synthesized on n-type Si (111 substrate via Au-catalyzed vapor-liquid-solid process. Morphology, crystal structure, and optical property of the as-synthesized GaN nanowires are characterized by means of X-ray diffraction, scanning/transmission electron microscopy, UV-vis diffuse reflection spectroscopy, and room temperature photoluminescence. The results indicate that the as-prepared GaN nanowires with a large aspect ratio are well crystallized in the hexagonal wurtzite structure, and a slight blue shift appears in both the absorption edge and emission peak probably due to the quantization effect. Photocatalytic H2 evolution over the as-prepared GaN nanowires is performed with the incorporation of Pt or Rh as the cocatalyst, exhibiting greatly enhanced capability compared to the GaN powder tested under the same conditions. Moreover, photocatalytic CO2 reduction over the GaN nanowires is also successfully realized using Pt or Rh as the cocatalyst, depending on which the products show a strong selectivity inherently related to the reductive electrons transferred by cocatalyst.

  5. Grain size reduction due to fracturing and subsequent grain-size-sensitive creep in a lower crustal shear zone in the presence of a CO2-bearing fluid

    Science.gov (United States)

    Okudaira, Takamoto; Shigematsu, Norio; Harigane, Yumiko; Yoshida, Kenta

    2017-02-01

    To understand rheological weakening in the lower continental crust, we studied mylonites in the Paleoproterozoic Eidsfjord anorthosite, northern Norway. The zones of anorthositic mylonites range from a few millimeters to several meters thick, and include ultramylonites and protomylonites. They contain syn-kinematic metamorphic minerals, including Cl-bearing amphibole and scapolite. Thermodynamic analysis reveals that syn-deformational hydration reactions occurred at ∼600 °C and ∼700 MPa under CO2-bearing conditions. The protomylonites contain many fragmented plagioclase porphyroclasts. The fractures in porphyroclasts are filled with fine-grained plagioclase, suggesting that fracturing is a common mechanism of grain size reduction. The anorthite contents of fine-grained polygonal matrix plagioclase are different from those of porphyroclastic plagioclase, suggesting that the matrix grains nucleated and grew during syn-kinematic metamorphism. Plagioclase aggregates in the matrices of mylonites do not exhibit a distinct crystallographic preferred orientation, which implies that the dominant deformation mechanism was grain-size-sensitive creep. Consequently, in the lower crustal anorthositic mylonites, grain size reduction occurred via fracturing, rather than through dynamic recrystallization, leading to grain-size-sensitive creep. The syn-kinematic recrystallization of minor phases at plagioclase grain boundaries may suppress the growth of plagioclase and contribute to the development of grain-size-sensitive creep.

  6. Heterologous Expression of the Clostridium carboxidivorans CO Dehydrogenase Alone or Together with the Acetyl Coenzyme A Synthase Enables both Reduction of CO2 and Oxidation of CO by Clostridium acetobutylicum.

    Science.gov (United States)

    Carlson, Ellinor D; Papoutsakis, Eleftherios T

    2017-08-15

    With recent advances in synthetic biology, CO2 could be utilized as a carbon feedstock by native or engineered organisms, assuming the availability of electrons. Two key enzymes used in autotrophic CO2 fixation are the CO dehydrogenase (CODH) and acetyl coenzyme A (acetyl-CoA) synthase (ACS), which form a bifunctional heterotetrameric complex. The CODH/ACS complex can reversibly catalyze CO2 to CO, effectively enabling a biological water-gas shift reaction at ambient temperatures and pressures. The CODH/ACS complex is part of the Wood-Ljungdahl pathway (WLP) used by acetogens to fix CO2, and it has been well characterized in native hosts. So far, only a few recombinant CODH/ACS complexes have been expressed in heterologous hosts, none of which demonstrated in vivo CO2 reduction. Here, functional expression of the Clostridium carboxidivorans CODH/ACS complex is demonstrated in the solventogen Clostridium acetobutylicum, which was engineered to express CODH alone or together with the ACS. Both strains exhibited CO2 reduction and CO oxidation activities. The CODH reactions were interrogated using isotopic labeling, thus verifying that CO was a direct product of CO2 reduction, and vice versa. CODH apparently uses a native C. acetobutylicum ferredoxin as an electron carrier for CO2 reduction. Heterologous CODH activity depended on actively growing cells and required the addition of nickel, which is inserted into CODH without the need to express the native Ni insertase protein. Increasing CO concentrations in the gas phase inhibited CODH activity and altered the metabolite profile of the CODH-expressing cells. This work provides the foundation for engineering a complete and functional WLP in nonnative host organisms.IMPORTANCE Functional expression of CO dehydrogenase (CODH) from Clostridium carboxidivorans was demonstrated in C. acetobutylicum, which is natively incapable of CO2 fixation. The expression of CODH, alone or together with the C. carboxidivorans acetyl

  7. Effect of Organic and Inorganic Fertilizer on the Emission of CO2 and N2O from the Summer Maize Field in the North China Plain%长期施用有机肥与化肥氮对华北夏玉米N2O和CO2排放的影响

    Institute of Scientific and Technical Information of China (English)

    李燕青; 唐继伟; 车升国; 温延臣; 孙文彦; 赵秉强

    2015-01-01

    chemical fertilizer and organic fertilizer in greenhouse gas (GHG) emission in the field. The present research will be helpful in establishing GHG emission reduction measures.[Method] In a 8 year field experiment, CO2 and N2O emission flux from the Fluvo-aquic soil of summer maize were measured for 5 months (from June to October in 2014) by using a static chamber-gas chromatograph technique, and GHG effect and total season emission were also estimated.[Result] Both the chemical fertilizer treatments and the organic fertilizer treatments had similar N2O emission curves. A temporary peak of N2O emission flux occurred after fertilization, and then the curves became stable. Under equal N rates, the N2O flux of chemical fertilizer treatments were significantly higher than that of organic fertilization treatments, but organic fertilization treatments were higher than chemical fertilizer treatments in a stable phase after the peaks. Chemical fertilizer had little influence on CO2 emission curves. Continuous peaks of CO2 emission flux occurred after application of organic fertilization. Both the organic fertilizer and chemical fertilizer can increase the emission of N2O. The emission of N2O increased with the increase of nitrogen application. Under equal N rates, total N2O emissions of chemical fertilizer treatments were significantly higher than organic fertilizer treatments. Application of organic fertilizer significantly increased CO2 emissions, but the effect of chemical fertilizer on CO2 emissions were not significant. When the N fertilizer rate was 240 kg·hm-2, both the chemical fertilizer treatments and organic fertilizer treatments had high level yields and a minimum GHGI, that were 0.27, 0.63 kg·hm-2. Treatments with a higher N rates than 240 kg·hm-2 had large GHGI values.[Conclusion]Application of more chemical or organic fertilizer would increase the emission of more greenhouse gas. Due to the carbon sequestration effect of the organic fertilizer, organic fertilizer

  8. Photocatalytic reduction of CO2 with Ag modified TiO2 under UV irradiation%Ag修饰TiO2催化剂紫外光催化还原CO2的研究

    Institute of Scientific and Technical Information of China (English)

    何志桥; 韩晶; 宋爽

    2014-01-01

    采用水解煅烧法制备了不同Ag修饰量的TiO2催化剂(Ag-TiO2).利用X射线衍射(XRD)、X射线光电子光谱(XPS)、透射电子显微镜(TEM)、比表面积测试(BET)和紫外-可见漫反射光谱(UV-vis)等技术分别对纯TiO2和Ag-TiO2样品进行了分析表征.探讨了在紫外光照射的CO2/NaOH水溶液中Ag-TiO2光催化还原CO2反应.研究表明:Ag-TiO2的光利用能力和碳转化能力都较纯TiO2的高,当Ag修饰量为1.0%时达到最大值,其产物量的大小顺序依次为H2>CH4>CH3OH>CO>HCHO.

  9. Photo-induced CO2 reduction by CH4/H2O to fuels over Cu-modified g-C3N4 nanorods under simulated solar energy

    Science.gov (United States)

    Tahir, Beenish; Tahir, Muhammad; Amin, Nor Aishah Saidina

    2017-10-01

    Copper modified polymeric graphitic carbon nitride (Cu/g-C3N4) nanorods for photo-induced CO2 conversion with methane (CH4) and water (H2O) as reducing system under simulated solar energy has been investigated. The nanocatalysts, synthesized by pyrolysis and sonication, were characterized by XRD, FTIR, Raman analysis, XPS, SEM, N2 adsorption-desorption and PL spectroscopy. The presence of Cu2+ ions over the g-C3N4 structure inhibited charge carriers recombination process. The results indicated that photo-activity and selectivity of Cu/g-C3N4 photo-catalyst for CO2 reduction greatly dependent on the type of CO2-reduction system. CO2 was efficiently converted to CH4 and CH3OH with traces of C2H4 and C2H6 hydrocarbons in the CO2-water system. The yield of the main product, CH4 over 3 wt.% Cu/g-C3N4 was 109 μmole g-cata.-1 h-1 under visible light irradiation, significantly higher than the pure g-C3N4 catalyst (60 μmole/g.cat). In photo-induced CO2-CH4 reaction, CO and H2 were detected as the main products with smaller amount of hydrocarbons. The highest efficiency was detected over 3 wt.%Cu-loading of g-C3N4 and at optimal CH4/CO2 feed ratio of 1.0. The maximum yield of CO and H2 detected were 142 and 76 μmole g-catal.-1 h-1, respectively at selectivity 66.6% and 32.5%, respectively. Significantly enhanced CO2/CH4 reduction over Cu/g-C3N4 was attributed to its polymeric structure with efficient charge transfer property and inhibited charges recombination rate. A proposed photo-induced reaction mechanism, corroborated with the experimental data, was also deliberated.

  10. From CO2 to cell: energetic expense of creating biomass using the Calvin-Benson-Bassham and reductive citric acid cycles based on genome data.

    Science.gov (United States)

    Mangiapia, Mary; Scott, Kathleen

    2016-04-01

    The factors driving the dominance of the Calvin-Benson-Bassham cycle (CBB) or reductive citric acid cycle (rCAC) in autotrophic microorganisms in different habitats are debated. Based on costs for synthesizing a few metabolic intermediates, it has been suggested that the CBB poses a disadvantage due to higher metabolic cost. The purpose of this study was to extend this estimate of cost from metabolite synthesis to biomass synthesis. For 12 gammaproteobacteria (CBB) and five epsilonproteobacteria (rCAC), the amount of ATP to synthesize a gram of biomass from CO2 was calculated from genome sequences via metabolic maps. The eleven central carbon metabolites needed to synthesize biomass were all less expensive to synthesize via the rCAC (66%-89% of the ATP needed to synthesize them via CBB). Differences in cell compositions did result in differing demands for metabolites among the organisms, but the differences in cost to synthesize biomass were small among organisms that used a particular pathway (e.g. rCAC), compared to the difference between pathways (rCAC versus CBB). The rCAC autotrophs averaged 0.195 moles ATP per g biomass, while their CBB counterparts averaged 0.238. This is the first in silico estimate of the relative expense of both pathways to generate biomass. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. CO2-Neutral Fuels

    NARCIS (Netherlands)

    Goede, A.; van de Sanden, M. C. M.

    2016-01-01

    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

  12. CO2-Neutral Fuels

    Science.gov (United States)

    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.

  13. CO2-Neutral Fuels

    NARCIS (Netherlands)

    Goede, A.; van de Sanden, M. C. M.

    2016-01-01

    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

  14. Identification of Possible Pathways for C-C Bond Formation during Electrochemical Reduction of CO2: New Theoretical Insights from an Improved Electrochemical Model.

    Science.gov (United States)

    Goodpaster, Jason D; Bell, Alexis T; Head-Gordon, Martin

    2016-04-21

    We have carried out a periodic Kohn-Sham density functional theory investigation of the pathways by which carbon-carbon bonds could be formed during the electrochemical reduction of CO2 on Cu(100) using a model that includes the effects of the electrochemical potential, solvent, and electrolyte. The electrochemical potential was set by relating the applied potential to the Fermi energy and then calculating the number of electrons required by the simulation cell for that specific Fermi energy. The solvent was included as a continuum dielectric, and the electrolyte was described using a linearized Poisson-Boltzmann model. The calculated potential of zero charge for a variety of surfaces agrees with experiment to within a mean average error of 0.09 V, thereby validating the assumptions of the model. Analysis of the mechanism for C-C bond formation revealed that at low-applied potential, C-C bond formation occurs through a CO dimer. However, at high applied potentials, a large activation barrier blocks this pathway; therefore, C-C bond formation occurs through reaction of adsorbed CHO and CO. Rate parameters determined from our calculations were used to simulate the kinetics of ethene formation during the electrochemical reduction of CO over a Cu(100) surface. An excellent match was observed between previously reported measurements of the partial current for ethene formation as a function of applied voltage and the variation in the partial current for C-C bond formation predicted by our microkinetic model. The electrochemical model reported here is simple, fairly easy to implement, and involves only a small increase in computational cost over calculations neglecting the effects of the electrolyte and the applied field. Therefore, it can be used to study the effects of applied potential and electrolyte composition on the energetics of surface reactions for a wide variety of electrochemical reactions.

  15. Reduced-order modeling with sparse polynomial chaos expansion and dimension reduction for evaluating the impact of CO2 and brine leakage on groundwater

    Science.gov (United States)

    Liu, Y.; Zheng, L.; Pau, G. S. H.

    2016-12-01

    A careful assessment of the risk associated with geologic CO2 storage is critical to the deployment of large-scale storage projects. While numerical modeling is an indispensable tool for risk assessment, there has been increasing need in considering and addressing uncertainties in the numerical models. However, uncertainty analyses have been significantly hindered by the computational complexity of the model. As a remedy, reduced-order models (ROM), which serve as computationally efficient surrogates for high-fidelity models (HFM), have been employed. The ROM is constructed at the expense of an initial set of HFM simulations, and afterwards can be relied upon to predict the model output values at minimal cost. The ROM presented here is part of National Risk Assessment Program (NRAP) and intends to predict the water quality change in groundwater in response to hypothetical CO2 and brine leakage. The HFM based on which the ROM is derived is a multiphase flow and reactive transport model, with 3-D heterogeneous flow field and complex chemical reactions including aqueous complexation, mineral dissolution/precipitation, adsorption/desorption via surface complexation and cation exchange. Reduced-order modeling techniques based on polynomial basis expansion, such as polynomial chaos expansion (PCE), are widely used in the literature. However, the accuracy of such ROMs can be affected by the sparse structure of the coefficients of the expansion. Failing to identify vanishing polynomial coefficients introduces unnecessary sampling errors, the accumulation of which deteriorates the accuracy of the ROMs. To address this issue, we treat the PCE as a sparse Bayesian learning (SBL) problem, and the sparsity is obtained by detecting and including only the non-zero PCE coefficients one at a time by iteratively selecting the most contributing coefficients. The computational complexity due to predicting the entire 3-D concentration fields is further mitigated by a dimension

  16. China urban resident's willingness to pay for carbon dioxide emission reductions%我国城镇居民对CO2减排的支付意愿调查研究

    Institute of Scientific and Technical Information of China (English)

    曾贤刚

    2011-01-01

    The factors which affect Chinese urban resident's willingness to pay (WTP) for CO2 emission reductions were investigated by using contingent valuation method (CVM).China urban resident's WTP was 132 yuan/year for reducing CO2emissions by 30% until the year 2050, 216 yuan/year for a reduction of 60%, and 264 yuan/year for a reduction of 85%.Through the general regression model analysis, it was found that the urban resident's education level, household's annual per capita income, job type, city location, cognitive level on climate change and environmental awareness were closely correlated with the WTP, and how the costs for reducing CO2 emissions should be shared among countries also had significant impact on the WTP.%运用权变评价法(CVM)调查了我国城镇居民对CO2减排的支付意愿.结果表明,我国城镇居民愿意为到2050年全球CO2_减排30%而每年支付132元;减排60%而每年支付216元;减排85%而每年支付264元.一般线性同归模型分析结果显示,城镇居民的受教育程度、家庭年收入、职业类型、所在城市、对气候变化的认知程度和环境意识,都对CO2减排的支付意愿有显著影响;而且不同的CO2减排成本分配方案对人们的支付意愿也有显著影响.

  17. Water as a Direct Hydrogen Donor in Supercritical Carbon Di-oxide: A Novel and Efficient Zn-H2O-CO2 System for Chemo selective Reduction of Nitrobenzenes to Anilines

    Institute of Scientific and Technical Information of China (English)

    JIANG Huan-Feng; DONG Yao-Sen

    2008-01-01

    An eco-friendly and cheap Zn-H2O-CO2 system was presented for chemoselective reduction of nitrobenzenes to anilines with high yields (80%-97% isolated yields) in supercritical carbon dioxide. This process brings together the very important green chemistry technologies--the use of carbon dioxide as a solvent and the use of water as a hydrogen donor.

  18. CO2 -Responsive polymers.

    Science.gov (United States)

    Lin, Shaojian; Theato, Patrick

    2013-07-25

    This Review focuses on the recent progress in the area of CO2 -responsive polymers and provides detailed descriptions of these existing examples. CO2 -responsive polymers can be categorized into three types based on their CO2 -responsive groups: amidine, amine, and carboxyl groups. Compared with traditional temperature, pH, or light stimuli-responsive polymers, CO2 -responsive polymers provide the advantage to use CO2 as a "green" trigger as well as to capture CO2 directly from air. In addition, the current challenges of CO2 -responsive polymers are discussed and the different solution methods are compared. Noteworthy, CO2 -responsive polymers are considered to have a prosperous future in various scientific areas.

  19. 基于LCA的高炉喷吹废塑料节能减排研究%LCA Analysis on Energy Consumption and CO2 Reduction of Injecting Plastic Into BF

    Institute of Scientific and Technical Information of China (English)

    刘颖昊; 刘涛

    2012-01-01

    基于LCA评价方法结合高炉喷吹废塑料技术开展节能减排研究,进行高炉喷吹废塑料情景下钢铁主要产品能耗和CO2气体减排分析.高炉喷吹废塑料后铁水、热轧卷和冷轧卷的能耗在钢厂边界内部有小幅度增加,随着喷吹比例的提高,增加幅度上升;而生命周期能耗有所减少,减少幅度随着喷吹比例的提高而增加;铁水、热轧卷和冷轧卷在钢厂边界内的CO2排放以及生命周期CO2排放都有不同程度的减少,随着喷吹比例的提高,CO2减排幅度迅速增加.%Combined with the injecting waste plastic into BF technology, LCA methodology was used to do analysis of the energy consumption and CO2 reduction of main products in steelworks. After injecting waste plastic into BF, the energy consumption of hot metal, hot rolling coil and cold rolling coil will have small increase in the boundary of steelworks. With a higher proportion of injection, the rate of increase is increased. The energy consumption of steel product will decrease in the boundary of whole life cycle. The rate of decrease is reduced with increasing injection ratio. The CO2 emission of hot metal, hot rolling coil and cold rolling coil will decrease both in the boundary of steelworks and the whole life cycle. Along with higher injection ratio, CO2 emissions reduction rate will be rapidly increased.

  20. CO2 laser modeling

    Science.gov (United States)

    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.

  1. Elevated pCO(2 )favours nitrate reduction in the roots of wild-type tobacco (Nicotiana tabacum cv. Gat.) and significantly alters N-metabolism in transformants lacking functional nitrate reductase in the roots.

    Science.gov (United States)

    Kruse, Jörg; Hetzger, Ilka; Hänsch, Robert; Mendel, Ralf-R; Walch-Liu, Pia; Engels, Christof; Rennenberg, Heinz

    2002-12-01

    The impact of elevated pCO(2 )on N-metabolism of hydroponically grown wild-type and transformed tobacco plants lacking root nitrate reduction was studied in order to elucidate the effects on (i) nitrate uptake, (ii) long-distance transport of N, (iii) nitrate reduction with emphasis on root-NR, and (iv) the allocation of N between the root and shoot. The findings were related to alterations of growth rates. At elevated pCO(2 )the wild type exhibited higher growth rates, which were accompanied by an increase of NO(3)(-)-uptake per plant, due to a higher root:shoot ratio. Furthermore, elevated pCO(2 )enhanced nitrate reduction in the roots of the wild type, resulting in enhanced xylem-loading of organic N (amino-N) to supply the shoot with sufficient nitrogen, and decreased phloem-transport of organic N in a basipetal direction. Transformed tobacco plants lacking root nitrate reduction were smaller than the wild type and exhibited lower growth rates. Nitrate uptake per plant was decreased in transformed plants as a consequence of an impeded root growth and, thus, a significantly decreased root:shoot ratio. Surprisingly, transformed plants showed an altered allocation of amino-N between the root and the shoot, with an increase of amino-N in the root and a substantial decrease of amino-N in the shoot. In transformed plants, xylem-loading of nitrate was increased and the roots were supplied with organic N via phloem transport. Elevated pCO(2 )increased shoot-NR, but only slightly affected the growth rates of transformed plants, whereas carbohydrates accumulated at elevated pCO(2 )as indicated by a significant increase of the C/N ratio in the leaves of transformed plants. Unexpectedly, the C/N balance and the functional equilibrium between root and shoot growth was disturbed dramatically by the loss of nitrate reduction in the root.

  2. Vaporization reduction characteristics of aqueous ammonia solutions by the addition of ethylene glycol, glycerol and glycine to the CO2 absorption process

    Institute of Scientific and Technical Information of China (English)

    Jong-Beom Seo; Soo-Bin Jeon; Je-Young Kim; Gang-Woo Lee; Jong-Hyeon Jung; Kwang-Joong Oh

    2012-01-01

    Aqueous ammonia(NH3)solution can be used as an alternative absorption for the control of CO2 emitted from flue gases due to its high absorption capacity,fast absorption rate and low corrosion problem.The emission of CO2 from iron and steel plants requires much attention,as they are higher than those emitted from power plants at a single point source.In the present work,low concentration ammonia liquor,9 wt.%,was used with various additives to obtain the kinetic properties using the blast furnace gas model.Although a solution with a high ammonia concentration enables high CO2 absorption efficiency,ammonium ions are lost as ammonia vapor,resulting in reduced CO2 absorption due to the lower concentration of the ammonia absorbent.To decrease the vaporization of ammonia,ethylene glycol,glycerol and glycine,which contain more than one hydroxyl radical,were chosen.The experiments were conducted at 313 K similar to the CO2 absorption conditions for the blast furnace gas model.

  3. Vaporization reduction characteristics of aqueous ammonia solutions by the addition of ethylene glycol, glycerol and glycine to the CO2 absorption process.

    Science.gov (United States)

    Seo, Jong-Beom; Jeon, Soo-Bin; Kim, Je-Young; Lee, Gang-Woo; Jung, Jong-Hyeon; Oh, Kwang-Joong

    2012-01-01

    Aqueous ammonia (NH3) solution can be used as an alternative absorption for the control of CO2 emitted from flue gases due to its high absorption capacity, fast absorption rate and low corrosion problem. The emission of CO2 from iron and steel plants requires much attention, as they are higher than those emitted from power plants at a single point source. In the present work, low concentration ammonia liquor, 9 wt.%, was used with various additives to obtain the kinetic properties using the blast furnace gas model. Although a solution with a high ammonia concentration enables high CO2 absorption efficiency, ammonium ions are lost as ammonia vapor, resulting in reduced CO2 absorption due to the lower concentration of the ammonia absorbent. To decrease the vaporization of ammonia, ethylene glycol, glycerol and glycine, which contain more than one hydroxyl radical, were chosen. The experiments were conducted at 313 K similar to the CO2 absorption conditions for the blast furnace gas model.

  4. CO2NNIE

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Andersen, Ove; Lewis-Kelham, Edwin

    2015-01-01

    We propose a system for calculating the personalized annual fuel consumption and CO2 emissions from transportation. The system, named CO2NNIE, estimates the fuel consumption on the fastest route between the frequent destinations of the user. The travel time and fuel consumption estimated are based......% of the actual fuel consumption (4.6% deviation on average). We conclude, that the system provides new detailed information on CO2 emissions and fuel consumption for any make and model....

  5. Wearable CO2 sensor

    OpenAIRE

    Radu, Tanja; Fay, Cormac; Lau, King-Tong; Waite, Rhys; Diamond, Dermot

    2009-01-01

    High concentrations of CO2 may develop particularly in the closed spaces during fires and can endanger the health of emergency personnel by causing serious physiological effects. The proposed prototype provides real-time continuous monitoring of CO2 in a wearable configuration sensing platform. A commercially available electrochemical CO2 sensor was selected due to its selectivity, sensitivity and low power demand. This was integrated onto an electronics platform that performed signal capture...

  6. Explaining Dutch emissions of CO2; a decomposition analysis

    OpenAIRE

    Alex Hoen; Machiel Mulder

    2003-01-01

    Decomposition of CO2 data of the Netherlands shows that much progress has been made with reduction of CO2 emissions by changing to less CO2 intensive technologies. Moreover, demand shifted to products that are produced with less CO2 emission. Further, shifts in the inputs needed in the production process also managed to decrease the CO2 emissions. These effects, however, were more than compensated by increased CO2 emission due to economic growth. Especially growth in exports led to substantia...

  7. Material and Structural Performance Evaluations of Hwangtoh Admixtures and Recycled PET Fiber-Added Eco-Friendly Concrete for CO2 Emission Reduction

    OpenAIRE

    Bon-Min Koo; Jang-Ho Jay Kim; Sung-Bae Kim; Sungho Mun

    2014-01-01

    In order to reduce carbon dioxide (CO2) emissions and produce an eco-friendly construction material, a type of concrete that uses a minimal amount of cement, yet still retains equivalent properties to ordinary cement concrete, has been developed and studied all over the world. Hwangtoh, a type of red clay broadly deposited around the world, has traditionally been considered an eco-friendly construction material, with bonus advantages of having health and cost benefits. Presently, Hwangtoh is ...

  8. Material and Structural Performance Evaluations of Hwangtoh Admixtures and Recycled PET Fiber-Added Eco-Friendly Concrete for CO2 Emission Reduction

    OpenAIRE

    Bon-Min Koo; Jang-Ho Jay Kim; Sung-Bae Kim; Sungho Mun

    2014-01-01

    In order to reduce carbon dioxide (CO2) emissions and produce an eco-friendly construction material, a type of concrete that uses a minimal amount of cement, yet still retains equivalent properties to ordinary cement concrete, has been developed and studied all over the world. Hwangtoh, a type of red clay broadly deposited around the world, has traditionally been considered an eco-friendly construction material, with bonus advantages of having health and cost benefits. Presently, Hwangtoh is ...

  9. Water-soluble IrIII N-heterocyclic carbene based catalysts for the reduction of CO2 to formate by transfer hydrogenation and the deuteration of aryl amines in water.

    Science.gov (United States)

    Azua, Arturo; Sanz, Sergio; Peris, Eduardo

    2011-03-28

    Two new water-soluble [IrI(2)(AcO)(bis-NHC)] complexes (NHC=N-heterocyclic carbene) incorporating a sulfonate functionality have been synthesized. The two complexes have been tested in the reduction of CO(2) with H(2) and iPrOH, and their activity has been compared with similar species without the sulfonate moiety. In both reactions, the complex with the two abnormally bound NHCs shows the best catalytic efficiencies, due to the higher σ-electron-donor character of the ligand. Remarkably, the activities obtained for the reduction of CO(2) under the transfer hydrogenation conditions are the best reported to date in terms of TON value (max. TON=2700). The two new complexes have also shown very good activity in the selective deuteration of arylamines, a process that is known to proceed through a chelate assisted N-directed process.

  10. Development of reactor configurations for an electrofuels platform utilizing genetically modified iron oxidizing bacteria for the reduction of CO2 to biochemicals.

    Science.gov (United States)

    Guan, Jingyang; Berlinger, Sarah A; Li, Xiaozheng; Chao, Zhongmou; Sousa E Silva, Victor; Banta, Scott; West, Alan C

    2017-03-10

    Electrofuels processes are potentially promising platforms for biochemical production from CO2 using renewable energy. When coupled to solar panels, this approach could avoid the inefficiencies of photosynthesis and there is no competition with food agriculture. In addition, these systems could potentially be used to store intermittent or stranded electricity generated from other renewable sources. Here we develop reactor configurations for continuous electrofuels processes to convert electricity and CO2 to isobutyric acid (IBA) using genetically modified (GM) chemolithoautotrophic Acidithiobacillus ferrooxidans. These cells oxidize ferrous iron which can be electrochemically reduced. During two weeks of cultivation on ferrous iron, stable cell growth and continuous IBA production from CO2 were achieved in a process where media was circulated between electrochemical and biochemical rectors. An alternative process with an additional electrochemical cell for accelerated ferrous production was developed, and this system achieved an almost three-fold increase in steady state cell densities, and an almost 4-fold increase in the ferrous iron oxidation rate. Combined, this led to an almost 8-fold increase in the steady state volumetric productivity of IBA up to 0.063±0.012mg/L/h, without a decline in energy efficiency from previous work. Continued development of reactor configurations which can increase the delivery of energy to the genetically modified cells will be required to increase product titers and volumetric productivities.

  11. CO2 blood test

    Science.gov (United States)

    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 ...

  12. CO2 laser resurfacing.

    Science.gov (United States)

    Fitzpatrick, R E

    2001-07-01

    The CO2 Laser offers a variety of unique features in resurfacing facial photodamage and acne scarring. These include hemostasis, efficient removal of the epidermis in a single pass, thermally induced tissue tightening, and safe, predictable tissue interaction. Knowledge of these mechanisms will result in the capability of using the CO2 laser effectively and safely whether the goal is superficial or deep treatment.

  13. 水泥工业CO2减排及利用技术进展%Technical Progress of Emission-reduction and Utilization of Carbon Dioxide in Cement Industry

    Institute of Scientific and Technical Information of China (English)

    马忠诚; 汪澜

    2011-01-01

    Emission-reduction exists potentially in cement industry, which is the key industry for carbon dioxide emission. Carbonate decomposition, fuel combustion and electric power consumption, etc. Which discharge carbon dioxide in cement industry, are introduced. A series of methods for decreasing carbon dioxide emission in cement industry, such as improving energy utilization, using alternative raw materials and fuels, developing new low carbone-mission binding materials, etc. Are expounded. Finally, several technologies for recycling of carbon dioxide, such as separation, capture, storage, fixation, etc. Are suggested.%水泥工业是CO2排放的重点行业,减排潜力巨大.全面介绍了水泥生产中碳酸盐分解、燃料燃烧和电力消耗等方面CO2的排放情况;详细阐述了水泥生产中通过提高能源利用率、使用替代原燃料、开发新型低碳排放的胶凝材料等措施实现CO2减排的方法,提出了对水泥工业CO2排放实施的分离、捕集、封存、固定等回收利用技术.

  14. Evaluation of the effect of a CO2 laser and fluoride on the reduction of carious lesions progression in primary teeth: an in vitro study

    Science.gov (United States)

    Zancopé, Bruna R.; Cesar, Marina M. C.; Rodrigues, Lidiany K. A.; Nobre-dos-Santos, Marinês

    2014-02-01

    This study aimed at investigating if CO2 laser irradiation (λ =10.6μm - 11.3 J/cm2) combined with fluoridated products, enhances the CaF2 formation on enamel surface and inhibits lesion progression of demineralized primary enamel. Thus, 135 demineralized primary enamel specimens (DES) were allocated to 9 groups (n=15) as follows: 1- DES only, 2- DES + pH cycling (control), 3- 1.23% acidulated phosphate fluoride gel (APF), 4- 1.23% fluoride foam (FF), 5- 5% fluoride varnish (FV), 6- CO2 Laser (L), 7 - Laser during APF application, 8-Laser during FF application and 9-Laser during FV application. Except for the demineralized enamel group, all specimens were submitted to a 7 day pH cycling regime. The knoop hardness number (KHN) was determined by cross-sectional microhardness analysis. After treatments application, three specimens of each group had their surface examined for CaF2 formation by scanning electron microscopy (SEM). The data was analyzed by ANOVA and Student's t-test (α= 0.05). Enamel mineral loss (ΔS) for groups 1 to 9 were respectively,(8,676.28+/-1,077.46b),(12,419.54+/-1,050.21a),(8,156.80+/-1,279.90b),(8,081.32+/-1,019.69b),(8,820.86+/-1,805. 99b),(8,723.45+/-1,167.14b),(9,003.17+/-796.90b),(8.229,03+/-961.25b),(9,023.32+/-1,1069b). The results showed statistically significant difference between control and all treatments groups (p0.05). SEM observations showed evidences of melting, fusion and calcium fluoride formation on enamel surface. In conclusion, laser irradiation alone or combined with fluoridated products inhibited lesion progression of demineralized primary enamel surface. However, no synergistic effect was observed when CO2 laser irradiation and fluoridated products application were combined.

  15. Economic crisis results in a worldwide reduction of CO2 emissions; Wirtschaftskrise beschert Rueckgang der weltweiten CO{sub 2}-Emissionen

    Energy Technology Data Exchange (ETDEWEB)

    Ziesing, Hans-Joachim

    2010-09-15

    The Copenhagen climate conference of December 2009 was not successful. On the other hand, 2009 was the first year when CO2 emissions decreased by 1.3 percent worldwide. The decrease was most pronounced win the industrialized countries of the West (7 percent) and in the transformation countries (nearly 9 percent). On the other hand, threshold countries and developing countries together showed an increase in the range of 4.5 percent. At the same time, climate-relevant gaseous emission sin total decreased by 6 percent in the industrialized countries. However, this is not the result of climate protection measures but of the global economic crisis. (orig.)

  16. PM2.5 from the Guanzhong Plain: Chemical composition and implications for emission reductions

    Science.gov (United States)

    Niu, Xinyi; Cao, Junji; Shen, Zhenxing; Ho, Steven Sai Hang; Tie, Xuexi; Zhao, Shuyu; Xu, Hongmei; Zhang, Ting; Huang, Rujin

    2016-12-01

    Atmospheric particulate matter (PM) affects important environmental issues including air quality, regional and global climates, and human health. A one-year sampling campaign for PM2.5 was conducted at six locations in Guanzhong Plain, including the cities of Xi'an, Weinan and Baoji, from March 2012 to March 2013. The 24-h average PM2.5 mass concentration was 134.7 μg m-3, that substantially exceeds the National Ambient Air Quality Standard level of 35 μg m-3. The highest loadings of both organic and elemental carbon (OC and EC) occurred in winter: EC co-varied with OC but showed less variability, presumably due to more stable emissions. The greatest contributions of secondary inorganic ions (SO42-, NO3- and NH4+) to the total quantified ions also were seen in winter, presumably due to gaseous precursors from coal combustion and biomass burning. Two high PM episodes occurred, one in the autumn and the other in winter. During the autumn episode, regional pollution from biomass burning raised the concentrations of secondary ions while coal combustion was a strong influence during the winter episode. Modeling simulations suggest that the control measures on both primary emissions and secondary aerosol precursors including SO2, NOx, and NH3 are needed to reduce the PM levels of the region.

  17. Atmospheric Fossil Fuel CO2 Tracing By 14C In Some Chinese Cities

    Science.gov (United States)

    Zhou, W.; Niu, Z.; Zhu, Y., Sr.

    2016-12-01

    CO2 plays an important role in global climate as a primary greenhouse gas in the atmosphere. Moreover, it has been shown that more than 70% of global fossil fuel CO2 (CO2ff) emissions are concentrated in urban areas (Duren and Miller, 2012). Our study focuses on atmospheric CO2ff concentrations in 15 Chinese cities using accelerator mass spectrometer (AMS) to measure 14C. Our objectives are: (1) to document atmospheric CO2ff concentrations in a variety of urban environments, (2) to differentiate the spatial-temporal variations in CO2ff among these cities, and (3) to ascertain the factors that control the observed variations. For about two years (winter 2014 to winter 2016), the CO2ff concentrations we observed from all sites varied from 5.1±4.5 ppm to 65.8±39.0 ppm. We observed that inland cities display much higher CO2ff concentrations and overall temporal variations than coastal cities in winter, and that northern cities have higher CO2ff concentrations than those of southern cities in winter. For inland cities relatively high CO2ff values are observed in winter and low values in summer; while seasonal variations are not distinct in the coastal cities. No significant (p > 0.05) differences in CO2ff values are found between weekdays and weekends as was shown previously in Xi'an (Zhou et al., 2014). Diurnal CO2ff variations are plainly evident, with high values between midnight and 4:00 am, and during morning and afternoon rush hours (Niu et al., 2016). The high CO2ff concentrations in northern inland cities in winter results mainly from the substantial consumption of fossil fuels for heating. The high CO2ff concentrations seen in diurnal measurements result mainly from variations in atmospheric dispersion, and from vehicle emissions related to traffic flows. The inter-annual variations in CO2ff in cities could provide a useful reference for local governments to develop policy around the effect of energy conservation and emission reduction strategies.

  18. Outsourcing CO2 Emissions

    Science.gov (United States)

    Davis, S. J.; Caldeira, K. G.

    2009-12-01

    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 consumption of goods and services in each country. This consumption-based emissions inventory differs from the production-based inventory because of imports and exports of goods and services that, either directly or indirectly, involved CO2 emissions. Using the latest available data and reasonable assumptions regarding trans-shipment of embodied carbon through third-party countries, we developed a global consumption-based CO2 emissions inventory and have calculated associated consumption-based energy and carbon intensities. We find that, in 2004, 24% of CO2 emissions are effectively outsourced to other countries, with much of the developed world outsourcing CO2 emissions to emerging markets, principally China. Some wealthy countries, including Switzerland and Sweden, outsource over half of their consumption-based emissions, with many northern Europeans outsourcing more than three tons of emissions per person per year. The United States is both a big importer and exporter of emissions embodied in trade, outsourcing >2.6 tons of CO2 per person and at the same time as >2.0 tons of CO2 per person are outsourced to the United States. These large flows indicate that CO2 emissions embodied in trade must be taken into consideration when considering responsibility for increasing atmospheric greenhouse gas concentrations.

  19. Redesigning the network of pedestrian spaces in the function of reduction of CO2 emission. Case study: Pančevo and Vršac

    Directory of Open Access Journals (Sweden)

    Đukić Aleksandra

    2012-01-01

    Full Text Available Research problem. The research problem is the increase of GHG and CO2 emissions in the transport sector, i.e. the intensification of urban transport activity in Serbia during the last 15 years. Focusing on redesigning of pedestrian networks as well as understanding the connections between urban design and pedestrian movement, the walkable environment could be achieved. In addition, as a direct result, a contribution would be made to a decrease of GHG and CO2 emission. Methodology. The following methods were used: analysis of the readability of open spaces, analysis of contents, rhythm and transparency on the ground floor of buildings and analysis of the intensity of use of open spaces using the Space Syntax method. Results. The results show a proportional relation between characteristics on ground floors of buildings and the intensity of pedestrian movement. Also, they enable the establishing of general recommendations for designing the immediate pedestrian environment and upgrading the quality of open public spaces. Conclusion. The improvement of the quality of pedestrian environment would have as its direct consequence greater use of open public spaces, and thus also increased intensity of pedestrian movement. In this manner, people would face a better quality and broader selection of contents and spaces.

  20. Energy- and CO2-reduction potentials by anaerobic treatment of wastewater and organic kitchen wastes in consideration of different climatic conditions.

    Science.gov (United States)

    Weichgrebe, D; Urban, I; Friedrich, K

    2008-01-01

    The classical municipal wastewater treatment in Germany consists of an aerobic carbon and nitrogen elimination and mostly an anaerobic sludge treatment. Organic kitchen wastes from separate waste collection as well as yard wastes are converted mostly in composting plants to soil conditioner. With these conventional types of treatment, the energy potential in waste and wastewater is lost due to aerobic material conversion. In this article three scenarios for the treatment of municipal wastewater and waste are compared on the subject of energy efficiency and useable potential: Sc1. the classical wastewater treatment and the composting of the organic waste fraction, Sc2. the anaerobic treatment of wastewater combined with deammonification and the digestion of the organic waste fraction, and Sc3. a mutual anaerobic treatment of wastewater and waste as co-digestion with deammonification. The calculation of energy and CO2-balance considers different climatic conditions. In case of using anaerobic treatment, not only the energy balance will be positive, also the CO2-balance is improved by the substitution of fossil fuels with generated biogas.

  1. Assessment of the impact of emissions reductions on air quality over North China Plain

    Science.gov (United States)

    Han, Xiao; Zhang, Meigen

    2016-04-01

    The production rate of secondary pollutants was highly non-linear with the emission intensity of their precursors. In this study, the air quality modeling system RAMS-CMAQ with zero-out sensitivity test was applied to conduct source sensitivity approaches of PM2.5 for four source categories (industry, power plants, transport, and residential) over the North China Plain (NCP) in January and July of 2013. The results show that the residential and industry emission sector were the greatest contributors to domain-wide PM2.5 in January and July, respectively. The largest variation could exceed 200 μg m-3 attributed to the residential sector in January when a heavy pollution period appeared, and could reach 40-60 μg m-3 attributed to the industry sector in July in the heavy pollution area, respectively. The nonlinear relationship between the secondary pollutant formation and its precursors was reflected by this source sensitivity approaches, as the summation of the secondary pollutant variations attributed to the four sources was obviously different from the simulated baseline concentration and the mass burden of nitrate would increase upon removal of the power plants or transport emission sector in the heavy pollution regions in January. Further analysis indicated that the improvement of atmospheric oxidation capacity due to emission sector removal coupled with the sufficient precursor nitrogen oxide under severe pollution background should be the main reason of the negative variation of nitrate appeared in the sensitivity test. This feature indicates that the atmospheric oxidation capacity is an important impact factor in determining the production rate of nitrate formation, and could further influence the variation feature of PM2.5 mass burden during the pollution episode. Thus, it is suggested that the comprehensive pollution control strategies should be implemented based on the specific pollution condition. Additionally, the nonlinearity of secondary pollutants

  2. Trend survey of the global environment adaptation type industrial technology. Trend survey of global environment related studies (researches on measureds for reduction of environmental load of CO2); Chikyu kankyo tekiogata sangyo gijutsu doko chosa. Chikyu kankyo kanren kenkyu doko no chosa (nisanka tanso no kankyo fuka teigensaku ni kansuru chosa kenkyu)

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    The paper studies the measures for reduction of environmental load of CO2 from the standpoint of chemical technology. As for methanol synthesis from CO2, accelerating of the reaction using Cu base compound catalyst is reported. Also, CO2 is methanated at high speed by low temperature waste heat using Ni-La2O3-Ru catalyst. Discussions are given on the subject for development of catalyst reaction relating to hydrogen production technology by methane reforming reaction using steam or CO2. Synthesis of polymetric materials by use of CO2 is also described. The paper mentions that it is indispensable to design high-function electrode and elucidate the reaction mechanism of electrochemical CO2 reduction for electrochemical and photochemical CO2 reduction measures. Moreover, in case of using solar energy, it is required to study photovoltaic excitation process in semiconductor electrode/ electrolyte solution interface. For production of hydrogen from CO2 by photosynthetic organisms and solar energy, the problem is control of inhibiting effect of oxygen combinedly produced. Described are production of polyhydroxy butyric acid and biodegradable polymer from CO2 and hydrogen by bacteria, and CO2 fixation imitating the enzyme reaction. 267 refs., 79 figs., 32 tabs.

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

    Science.gov (United States)

    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.

  4. BiOCl/g-C3N4异质结催化剂可见光催化还原CO2%BiOCl/g-C3N4 heterojunction catalyst for efficient photocatalytic reduction of CO2 under visible light

    Institute of Scientific and Technical Information of China (English)

    何志桥; 陈锦萍; 童丽丽; 汤俊涛; 陈建孟; 宋爽

    2016-01-01

    BiOCl/g-C3N4 heterojunction catalyst was synthesized by a hydrothermal method using KCl, Bi(NO3)3 and g-C3N4 as precursors, over which the photocatalytic reduction of CO2 under visible light irradiation was conducted. The catalytic activity and the stability during CO2 photoreduction was studied. Moreover, effects of molar ratio of BiOCl to g-C3N4, usage amount of catalyst and illumination intensity on the photocatalytic reduction of CO2 was investigated. It suggests that the BiOCl/g-C3N4 heterojunction catalysts showed much enhanced photocatalytic activities for the reduction of gaseous CO2 with water vapor in comparison with BiOCl and g-C3N4. The BiOCl/g-C3N4 catalyst with molar ratio of 1:1 exhibited the highest photocatalytic activity for CO2 reduction under the optimal conditions of 0.1 g catalyst and 2.413×10−6 einstein·min−1·cm−2 of illumination intensity. Moreover, the catalyst maintained stable performance even after five cycles of test. Techniques of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller analyses and UV-vis absorption spectroscopy were conducted on the catalyst, and it is speculated that the effective separation of photogenerated electrons and holes due to the formation of p-n heterojunctions between BiOCl and g-C3N4 accounted for the improved photocatalytic activities of BiOCl/g-C3N4.%以KCl、Bi(NO3)3和类石墨氮化碳(g-C3N4)为前体,采用水热法成功制备了BiOCl/g-C3N4异质结光催化剂,并进行可见光催化还原CO2,考察了催化剂的活性及稳定性,同时研究BiOCl:g-C3N4(摩尔比)、催化剂用量和光照强度对光催化还原CO2的影响。结果表明,在水蒸气的存在下,BiOCl/g-C3N4较纯BiOCl和g-C3N4具有更高的光催化还原CO2活性,在催化剂用量为0.1 g,光照强度为2.413×10−6 einstein·min−1·cm−2,BiOCl:g-C3N4摩尔比为1:1的异质结催化剂显

  5. CO2 emissions in the steel industry

    Directory of Open Access Journals (Sweden)

    M. Kundak

    2009-07-01

    Full Text Available Global CO2 emissions caused by the burning of fossil fuels over the past century are presented. Taking into consideration the total world production of more than 1,3 billion tons of steel, the steel industry produces over two billion tons of CO2. Reductions in CO2 emissions as a result of technological improvements and structural changes in steel production in industrialized countries during the past 40 years are described. Substantial further reductions in those emissions will not be possible using conventional technologies. Instead, a radical cutback may be achieved if, instead of carbon, hydrogen is used for direct iron ore reduction. The cost and the ensuing CO2 generation in the production of hydrogen as a reducing agent from various sources are analysed.

  6. CO2-strategier

    DEFF Research Database (Denmark)

    Jørgensen, Michael Søgaard

    2008-01-01

    I 2007 henvendte Lyngby-Taarbæk kommunens Agenda 21 koordinator sig til Videnskabsbutikken og spurgte om der var interesse for at samarbejde om CO2-strategier. Da Videnskabsbutikken DTU er en åben dør til DTU for borgerne og deres organisationer, foreslog Videnskabsbutikken DTU at Danmarks...... Naturfredningsforening’s lokalkomité for Lyngby blev en del af samarbejdet for at få borgerne i kommunen involveret i arbejdet med at udvikle strategier for reduktion af CO2. Siden sommeren 2007 har Videnskabsbutikken DTU, Lyngby-Taarbæk kommune og Danmarks Naturfredningsforening i Lyngby-Taarbæk samarbejdet om analyse...... og innovation i forhold til CO2-strategier....

  7. Selective photocatalytic reduction of CO2 by H2O/H2 to CH4 and CH3OH over Cu-promoted In2O3/TiO2 nanocatalyst

    Science.gov (United States)

    Tahir, Muhammad; Tahir, Beenish; Saidina Amin, Nor Aishah; Alias, Hajar

    2016-12-01

    Photocatalytic CO2 reduction by H2O and/or H2 reductant to selective fuels over Cu-promoted In2O3/TiO2 photocatalyst has been investigated. The samples, prepared via a simple and direct sol-gel method, were characterized by XRD, SEM, TEM, XPS, N2 adsorption-desorption, UV-vis diffuse reflectance, Raman and PL spectroscopy. Cu and In loaded into TiO2, oxidized as Cu2+ and In3+, promoted efficient separation of photo-generated electron/hole pairs (e-/h+). The results indicate that the reduction rate of CO2 by H2O to CH4 approached to 181 μmol g-1 h-1 using 0.5% Cu-3% In2O3/TiO2 catalyst, a 1.53 fold higher than the production rate over the 3% In2O3/TiO2 and 5 times the amount produced over the pure TiO2. In addition, Cu was found to promote efficient production of CH3OH and yield rate reached to 68 μmol g-1 h-1 over 1% Cu-3% In2O3/TiO2 catalyst. This improvement was attributed to charge transfer property and suppressed recombination rate by Cu-metal. More importantly, H2 reductant was less favorable for CH4 production, yet a significant amount of CH4 and CH3OH were obtained using a mixture of H2O/H2 reductant. Therefore, Cu-loaded In2O3/TiO2 catalyst has shown to be capable for methanol production, whereas product selectivity was greatly depending on the amount of Cu-loading and the type of reductant. A photocatalytic reaction mechanism was proposed to understand the experimental results over the Cu-loaded In2O3/TiO2 catalyst.

  8. Simulating ocean acidification and CO2 leakages from carbon capture and storage to assess the effects of pH reduction on cladoceran Moina mongolica Daday and its progeny.

    Science.gov (United States)

    Wang, Zaosheng; Wang, Youshao; Yan, Changzhou

    2016-07-01

    In order to evaluate the effects of pH reduction in seawater as a result of increasing levels of atmospheric CO2, laboratory-scale experiments simulating the scenarios of ocean acidification (OA) and CO2 leakages of carbon capture and storage (CCS) were performed using the model organism Moina mongolica Daday. The LpH50s calculated in cladoceran toxicity tests showed that M. mongolica exhibited intermediate sensitivity to OA, which varied among species and with ontogeny, when compared with different phyla or classes of marine biota. Survival, reproduction and fecundity of parthenogenetic females were evaluated after 21-day exposures. Results showed that increased acidity significantly reduced the rate of reproduction of M. mongolica resulting in a decreased intrinsic rate of natural increase (rm) across the gradients of pH reduction. The analysis of macromolecule contents in neonates suggested that nutritional status in progeny from all broods were significantly reduced as seawater pH decreased, with increasing magnitude in latter broods, except the contents of protein from two former broods and lipids from the first brood. Our findings clearly showed that for this ecologically and economically important fish species, the negative effects of pH reduction on both "quantity" and "quality" of progeny may have far-reaching implications, providing direct evidence that OA could influence the energetic transfer of marine food web and ecosystem functions in acidified oceans in the future.

  9. Statistical analysis of thermal efficiency in industrial furnaces in Japan and determination of CO2 reduction amount realized by improving the efficiency; Nippon no kogyoro ni okeru netsukoritsu no tokeiteki kaiseki to sono kaizen ni yoru CO2 sakugenryo no suitei

    Energy Technology Data Exchange (ETDEWEB)

    Iwabayashi, T.; Matsuhashi, T.; Ishitani, H. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering; Tanabe, K. [The Energy Conservation Center Japan, Tokyo (Japan); Tanaka, R. [The Japan Industrial Furnace Manufacturers Association, Tokyo (Japan); Takashima, T.

    1997-01-30

    Analyses and evaluations were given on heating furnaces and heat treatment furnaces used in the Japanese steel and iron industry to calculate amounts of energy and CO2 that could be reduced by introducing a new furnace. The analyses have derived factors affecting thermal efficiency of the heating furnaces by using regression analysis. Discussions were given on a high-temperature air combustion system and a stored heat combustion system as new furnace technologies. As a result, it was disclosed that the current fuel consumption could be reduced to about 40% to 80% only by performing air pre-heating ideally and suppressing heat loss from furnace walls. This concept is sufficiently payable in terms of economy. It was also revealed that fuel consumption could be reduced to about 12% to 36% and CO2 discharge could be reduced in proportion with reduction in the fuel consumption, if ideal preheating can be carried out on materials to be heated. Furthermore, a result was obtained that the present thermal efficiency of 26.86% in nonferrous industries such as for copper and aluminum could be increased up to 53.37%. 10 refs., 19 figs., 1 tab.

  10. In vitro study of the effect of a pulsed 10.6μm CO2 laser and fluoride on the reduction of carious lesions progression in bovine root dentin

    Science.gov (United States)

    Parisotto, Thaís M.; Sacramento, Patrícia A.; Alves, Marcelo C.; Puppin-Rontani, Regina M.; Gavião, Maria Beatriz D.; Nobre-dos-Santos, Marin"s.

    2010-02-01

    The aim of the present study was to evaluate the combined in vitro effects a pulsed 10.6 μm CO2 laser and fluoride on the reduction of carious lesion progression in root dentin. Sixty five slabs of previously demineralized bovine root dentin were assigned into five groups (n=13): control (no treatment), acidulated phosphate fluoride gel 1.23% (FFA), CO2 Laser (L), FFA+L, L+FFA. The lasered groups were irradiated with 4.0J/cm2. After a 7 day pH cycling regime, the knoop hardness number (KHN) was determined by cross-sectional microhardness testing (5g, 5s, 10-60 μm, 10 μm interval). The data was analyzed by ANOVA and Student's t-test (α= 0.05). A significant interaction between KHN and the indentation depths was found (p0.05). At 30 μm, the KHN was significantly higher than the control only in the FFA group (KHN:15.35+/-1.16). At 40 μm, the groups FFA (KHN: 15.87+/-3.76), L (KHN: 15.57+/-5.71) and L+FFA (KHN:15.50+/-5.08) were capable of significantly inhibiting caries progression, however they did not differ each other (p>0.05). At depths of 50-60 μm, only group L (KHN:17.05+/-1.29/18.26+/-1.30) differed statistically from the control (KHN:13.43+/-1.24/13.81+/-1.25), but not from the other groups. In conclusion, CO2 laser alone was able to inhibit caries progression in the deepest layers. However, no synergistic effect was obtained when CO2 laser irradiation and FFA application and were combined.

  11. Analyzing Agricultural Sustainability Indicators,Under Energy Subsidy Reduction Policy(Case Study of Qorveh Plain

    Directory of Open Access Journals (Sweden)

    H. Balali

    2016-03-01

    Full Text Available Introduction: Generally, subsidies are the amounts of government payments in order to provide all society members with minimum well-being. In several countries such as Iran, the agriculture sector is supported by different methods to achieve goals such as increasing farmers' income, supporting domestic producers and eliminating dependence on imports, preserving employment and reducing poverty. A significant part of agriculture subsidies has been allocated to energy resources, chemical fertilizers, seeds, agriculture machines, vaccines, animal toxins, the interest on bank loans, insurance fees, certain airplane services, distributing young saplings, and government guaranteed purchase of products. However, examining the subsidies system in Iran reveals that most government payments are in the agriculture sector and more specifically on energy resources. Recently, the extra low cost of energy in the agriculture sector, which has had certain government supports, has resulted in low productivity and environmental damage, and has resulted in increased demand for agricultural products due to population growth, changes in life pattern, deviation in energy cost in agricultural sector, environment destruction and influences on sustainable agriculture indicators. Moreover, among different production units, agriculture has the closest relationship with the environment. This relationship is a mutual.On the one hand, erosion and destruction of the environment along with pollution growth and shortage of water resources negatively influences the production and efficiency of agricultural products, and on the other hand, agricultural pollutants and irregular use of chemical fertilizers in this sector impose indispensable damages to the environment.This study aims to apply a partial equilibrium model in order to examine direct and indirect effects of reduction of energy subsidies on economic and environmental indicators of agricultural sustainability in the Qorveh

  12. Material and Structural Performance Evaluations of Hwangtoh Admixtures and Recycled PET Fiber-Added Eco-Friendly Concrete for CO2 Emission Reduction

    Directory of Open Access Journals (Sweden)

    Bon-Min Koo

    2014-08-01

    Full Text Available In order to reduce carbon dioxide (CO2 emissions and produce an eco-friendly construction material, a type of concrete that uses a minimal amount of cement, yet still retains equivalent properties to ordinary cement concrete, has been developed and studied all over the world. Hwangtoh, a type of red clay broadly deposited around the world, has traditionally been considered an eco-friendly construction material, with bonus advantages of having health and cost benefits. Presently, Hwangtoh is not commonly used as a modern construction material due to properties such as low strength and high rates of shrinkage cracking. Recent studies, however, have shown that Hwangtoh can be used as a mineral admixture to improve the strength of concrete. In addition, polyethylene terephthalate (PET fibers recycled from PET bottle waste can be used to control shrinkage cracks in Hwangtoh concrete. Therefore, in this study, performance verification is conducted on newly developed Hwangtoh concrete mixed with short recycled PET fibers. The results show that Hwangtoh concrete has compressive strength, elastic modulus, and pH properties that are similar to these features in ordinary cement concrete. The properties of carbonation depth and creep strain of Hwangtoh concrete, however, are larger and smaller, respectively, than in ordinary cement concrete. According to flexural tests, reinforced concrete (RC specimens cast with Hwangtoh admixtures (with and without PET fibers possess similar or better capacities than ordinary RC specimens. The addition of PET fibers significantly improves the structural ductility of RC specimens under normal environmental conditions. However, the implementations of the concrete in aggressive environment must be carefully considered, since a previous study result indicates degradation of its durability performance in aggressive environments, such as seawater [1]. The results of this study validate the possibility of using eco

  13. CO2-neutral fuels

    Science.gov (United States)

    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

  14. CO2-neutral fuels

    Directory of Open Access Journals (Sweden)

    Goede A. P. H.

    2015-01-01

    Full Text Available 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

  15. Elevated CO2 and Soil Nitrogen Cycling

    Science.gov (United States)

    Hofmockel, K.; Schlesinger, W.

    2002-12-01

    Although forests can be large terrestrial carbon sinks, soil fertility can limit carbon sequestration in response to increased atmospheric CO2. During five years of CO2 fertilization (ambient + 200ppm) at the Duke Free-Air CO2 Enrichment (FACE) site, net primary production increased significantly by an average of 25% in treatment plots. Total nitrogen in the foliar canopy increased by 16%, requiring an additional 1.3 g N m-2yr-1 to be taken up from soils under elevated CO2. Mechanisms supporting increased nitrogen acquisition have not been identified. Here we report on biological N-fixation rates, using the acetylene reduction assay, in litter and mineral soil during three years of the CO2 enrichment experiment. Lack of a significant CO2 treatment effect on acetylene reduction indicates that carbon is not directly limiting biological N fixation. Nutrient addition experiments using a complete block design with glucose, Fe, Mo and P indicate biological N fixation is co-limited by molybdenum and carbon. These results suggest even if elevated atmospheric CO2 enhances below-ground carbon availability via root exudation, biological nitrogen fixation may not be stimulated due to micronutrient limitations. Assessment of future carbon sequestration by forest stands must consider limitations imposed by site fertility, including micronutrients.

  16. Structurally simple complexes of CO2

    OpenAIRE

    Murphy, Luke J.; Robertson, Katherine N.; Richard A. Kemp; TUONONEN, Heikki; Clyburne, Jason A. C.

    2015-01-01

    The ability to bind CO2 through the formation of low-energy, easily-broken, bonds could prove invaluable in a variety of chemical contexts. For example, weak bonds to CO2 would greatly decrease the cost of the energy-intensive sorbent-regeneration step common to most carbon capture technologies. Furthermore, exploration of this field could lead to the discovery of novel CO2 chemistry. Reduction of complexed carbon dioxide might generate chemical feedstocks for the preparation of value-added p...

  17. Nanoparticle-based concretes for the restoration of historical and contemporary buildings: a new way for CO2 reduction in architecture

    Science.gov (United States)

    Greco, Enrico; Ciliberto, Enrico; Verdura, Pietro Damiano; Lo Giudice, Elio; Navarra, Giuseppe

    2016-05-01

    The production of the cement is a highly energy-intensive process and contributes to the release of pollutants into the atmosphere due to both the chemical reactions occurring in the kiln and, in most cases, the burning of fossil fuels for power production. So, the reduction of the cement content in a concrete would be indirectly useful to decrease the pollutant emissions in the atmosphere. The results of our investigation indicate that the replacement levels of cement by the 4 % of nanoparticles show a positive increasing of many physical and chemical properties allowing a relevant saving of cement content inside a concrete mixture. The compressive strengths, tensile splitting, propagations of ultrasonic pulses and water permeability tests were investigated on different models and realistic structures by the ISO EN rules. The influence of the nanoparticles on physical and mechanical properties was measured at different ripening times. Both silica and iron oxides make cement pastes harder and accelerated hydration processes of the cements. A remarkable decreasing in water permeability was also observed showing that nanoconcretes can be used as innovative restoration systems for cement-based historical and contemporary artefacts in order to avoid carbonation processes. Moreover, a smaller quantity of cement binder inside the mortar causes relevant positive effects on the reduction of carbon dioxide emission in the atmosphere.

  18. Reaction Mechanisms of CO2 Reduction to Formaldehyde Catalyzed by Hourglass Ru, Fe, and Os Complexes: A Density Functional Theory Study

    Directory of Open Access Journals (Sweden)

    Chunhua Dong

    2016-12-01

    Full Text Available The reaction mechanisms for the reduction of carbon dioxide to formaldehyde catalyzed by bis(tricyclopentylphosphine metal complexes, [RuH2(H2(PCyp32] (1Ru, [FeH2(H2(PCyp32] (1Fe and [OsH4(PCyp32] (1Os, were studied computationally by using the density functional theory (DFT. 1Ru is a recently reported highly efficient catalyst for this reaction. 1Fe and 1Os are two analogues of 1Ru with the Ru atom replaced by Fe and Os, respectively. The total free energy barriers of the reactions catalyzed by 1Ru, 1Fe and 1Os are 24.2, 24.0 and 29.0 kcal/mol, respectively. With a barrier close to the experimentally observed Ru complex, the newly proposed iron complex is a potential low-cost catalyst for the reduction of carbon dioxide to formaldehyde under mild conditions. The electronic structures of intermediates and transition states in these reactions were analyzed by using the natural bond orbital theory.

  19. CO2 Interaction with Geomaterials (Invited)

    Science.gov (United States)

    Romanov, V.; Howard, B. H.; Lynn, R. J.; Warzinski, R. P.; Hur, T.; Myshakin, E. M.; Lopano, C. L.; Voora, V. K.; Al-Saidi, W. A.; Jordan, K. D.; Cygan, R. T.; Guthrie, G. D.

    2010-12-01

    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 #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

  20. Electrochemical CO2 reduction to formic acid on crystalline SnO2 nanosphere catalyst with high selectivity and stability%高选择性和稳定性SnO2纳米催化剂上 CO2电化学还原为甲酸

    Institute of Scientific and Technical Information of China (English)

    付奕舒; 李亚楠; 张霞; 刘予宇; 周晓东; 乔锦丽

    2016-01-01

    A novel catalyst for CO2 electroreduction based on nanostructured SnO2 was synthesized using a facile hydrothermal self‐assembly method. The electrochemical activity showed that the catalyst gave outstanding catalytic activity and selectivity in CO2 electroreduction. The catalytic activity and formate selectivity depended strongly on the electrolyte conditions. A high faradaic efficiency, i.e., 56%, was achieved for formate formation in KHCO3 (0.5 mol/L). This is attributed to control of formate production by mass and charge transfer processes. Electrolysis experiments using SnO2‐50/GDE (an SnO2‐based gas‐diffusion electrode, where 50 indicates the 50%ethanol content of the electrolyte) as the catalyst, showed that the electrolyte pH also affected CO2 reduction. The optimum electrolyte pH for obtaining a high faradaic efficiency for formate production was 8.3. This is mainly because a neutral or mildly alkaline environment maintains the oxide stability. The fara‐daic efficiency for formate production declined with time. X‐ray photoelectron spectroscopy showed that this is the result of deposition of trace amounts of fluoride ions on the SnO2‐50/GDE surface, which hinders reduction of CO2 to formate.%作为最重要的还原产品,甲酸是 CO2还原中非常有价值的液体燃料.已有研究报道, Sn类金属电极对甲酸生成有很好的催化活性,所用电解液均为 KHCO3溶液(0.5 mol/L),但多数研究没有对其电解液条件的影响给出清晰解释.一般而言,电解液 pH值会影响 H2O和 CO2还原的电极电势,酸性环境有利于氢析出,碱性环境则不利于甲酸形成.在中性偏碱性环境, CO2电解可以提供维持氧化物稳定性的可能性.同时,电解质浓度也极大地影响甲酸形成.研究表明,当在固定床反应器中使用 Sn颗粒电极,在 KHCO3溶液(0.5 mol/L)中甲酸的法拉第效率比 K2CO3溶液(0.1 mol/L)的法拉第效率更大.我们研究组通过简单的水热自组装法

  1. Biogenic hydrogen conversion of de-oiled jatropha waste via anaerobic sequencing batch reactor operation: process performance, microbial insights, and CO2 reduction efficiency.

    Science.gov (United States)

    Kumar, Gopalakrishnan; Lin, Chiu-Yue

    2014-01-01

    We report the semicontinuous, direct (anaerobic sequencing batch reactor operation) hydrogen fermentation of de-oiled jatropha waste (DJW). The effect of hydraulic retention time (HRT) was studied and results show that the stable and peak hydrogen production rate of 1.48 L/L ∗ d and hydrogen yield of 8.7 mL H2/g volatile solid added were attained when the reactor was operated at HRT 2 days (d) with a DJW concentration of 200 g/L, temperature 55 °C, and pH 6.5. Reduced HRT enhanced the production performance until 1.75 d. Further reduction has lowered the process efficiency in terms of biogas production and hydrogen gas content. The effluent from hydrogen fermentor was utilized for methane fermentation in batch reactors using pig slurry and cow dung as seed sources. The results revealed that pig slurry was a feasible seed source for methane generation. Peak methane production rate of 0.43 L CH4/L ∗ d and methane yield of 20.5 mL CH4/g COD were observed at substrate concentration of 10 g COD/L, temperature 30 °C, and pH 7.0. PCR-DGGE analysis revealed that combination of cellulolytic and fermentative bacteria were present in the hydrogen producing ASBR.

  2. Biogenic Hydrogen Conversion of De-Oiled Jatropha Waste via Anaerobic Sequencing Batch Reactor Operation: Process Performance, Microbial Insights, and CO2 Reduction Efficiency

    Directory of Open Access Journals (Sweden)

    Gopalakrishnan Kumar

    2014-01-01

    Full Text Available We report the semicontinuous, direct (anaerobic sequencing batch reactor operation hydrogen fermentation of de-oiled jatropha waste (DJW. The effect of hydraulic retention time (HRT was studied and results show that the stable and peak hydrogen production rate of 1.48 L/L*d and hydrogen yield of 8.7 mL H2/g volatile solid added were attained when the reactor was operated at HRT 2 days (d with a DJW concentration of 200 g/L, temperature 55°C, and pH 6.5. Reduced HRT enhanced the production performance until 1.75 d. Further reduction has lowered the process efficiency in terms of biogas production and hydrogen gas content. The effluent from hydrogen fermentor was utilized for methane fermentation in batch reactors using pig slurry and cow dung as seed sources. The results revealed that pig slurry was a feasible seed source for methane generation. Peak methane production rate of 0.43 L CH4/L*d and methane yield of 20.5 mL CH4/g COD were observed at substrate concentration of 10 g COD/L, temperature 30°C, and pH 7.0. PCR-DGGE analysis revealed that combination of celluloytic and fermentative bacteria were present in the hydrogen producing ASBR.

  3. 华北平原杨树人工林5种植被类型土壤CO2通量研究%Soil CO2 Flux of Five Types of Vegetation in Poplar Plantation of Chinese North Plain Region

    Institute of Scientific and Technical Information of China (English)

    高东; 鲁绍伟; 饶良懿; 杨晓菲; 耿绍波; 李文斌

    2010-01-01

    利用Licor-8100土壤CO2通量测定系统对华北平原地区5种不同密度和类型杨树人工林2009年10月份的土壤呼吸通量进行了观测、比较和分析.结果表明:(1)在短时间尺度上,它们的土壤呼吸通量有显著的差别,表现出明显的空间异质性.其大小顺序为:8 m行宽林间小藜、牛筋草地>2 m行宽林问苍耳地>8 m行宽林间水蓼、灰灰菜地>8 m行宽林间苍耳地>2 m宽林间裸地,其中平均值最大呼吸通量为3.23 μmol/(m2·s),最小为1.87μmol/(m2·s).(2)造成各植被类型和密度土壤呼吸差异的因素有土壤草根密度、与杨树的距离和地表空气流通性.(3)5种类型和密度的土壤呼吸通量的日变化过程并不一致,除8 m行宽林间小藜、牛筋草地和8 m行宽林间水蓼、灰灰菜地的呼吸通量与温度有较一致的规律,呈单峰型外,其余无明显的变化规律.(4)在较大时间尺度上,空气温度,土壤含水率和空气湿度有显著的相关关系;随着空气温度、土壤含水率和空气湿度的下降,土壤呼吸通量在一个月内呈逐渐的下降趋势.

  4. On Leakage from Geologic Storage Reservoirs of CO2

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Application of CO2 in BOF%转炉应用CO2技术

    Institute of Scientific and Technical Information of China (English)

    万雪峰; 曹东; 刘祥; 朱晓雷; 廖相巍

    2015-01-01

    By the thermodynamic analysis of top blowing CO2 in the converter,combined with laboratory simulation re-sult of top blowing O2+CO2 mixture gas in converter,some key parameters of CO2 used in converter were established. It is concluded that although pure CO2 injected in the converter could achieve decarburize,the drop of temperature was rath-er large. When the CO2 supplying intensity was 3.0 m3/(t·min),the reduction of temperature was 15.1℃/min;By blow-ing O2+CO2 mixture gas,temperature balance could be realized,but the largest theoretical proportion of CO2 in mixture gas was 79.1%;with the increase of CO2 proportion,the carbon and oxygen product of molten steel at the blowing end was reduced,under the condition of φ(CO2)∶φ(O2)=1∶1,the carbon and oxygen product could be controlled in the range of (25~32)×10-8.%通过对转炉顶吹CO2的热力学分析,结合实验室模拟转炉顶吹O2+CO2混合气体试验结果,确立了CO2在转炉中应用的关键参数。得出在转炉中顶吹纯CO2虽可脱碳,但温降较大,顶吹CO2供气强度为3.0 m3/(t·min)时,钢液温降速率为15.1℃/min;通过喷吹O2+CO2混合气体可实现温度平衡,但CO2配比的最大理论比例为79.1%;随着混合气体中CO2比例增大,吹炼终点钢液碳氧积降低,当φ(CO2)∶φ(O2)=1∶1时可控碳氧积为(25~32)×10-8。

  6. CO2 emissions from Super-light Structures

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl; Bagger, Anne

    2011-01-01

    rise to a substantial reduction of the CO2 emission in the construction phase. The present paper describes how the CO2 emission is reduced when using Super-light technology instead of traditional structural components. Estimations of the CO2 emissions from a number of projects using various...... construction methods suggest that building with Super-light structures may cut the CO2 emission in half, compared to traditional concrete structures, and reduce it to 25% compared to traditional steel structures....

  7. CO2 laser preionisation

    Science.gov (United States)

    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. The Abundance of Atmospheric CO2 in Ocean Exoplanets: a Novel CO2 Deposition Mechanism

    Science.gov (United States)

    Levi, A.; Sasselov, D.; Podolak, M.

    2017-03-01

    We consider super-Earth sized planets which have a water mass fraction large enough to form an external mantle composed of high-pressure water-ice polymorphs and also lack a substantial H/He atmosphere. We consider such planets in their habitable zone, so that their outermost condensed mantle is a global, deep, liquid ocean. For these ocean planets, we investigate potential internal reservoirs of CO2, the amount of CO2 dissolved in the ocean for the various saturation conditions encountered, and the ocean-atmosphere exchange flux of CO2. We find that, in a steady state, the abundance of CO2 in the atmosphere has two possible states. When wind-driven circulation is the dominant CO2 exchange mechanism, an atmosphere of tens of bars of CO2 results, where the exact value depends on the subtropical ocean surface temperature and the deep ocean temperature. When sea-ice formation, acting on these planets as a CO2 deposition mechanism, is the dominant exchange mechanism, an atmosphere of a few bars of CO2 is established. The exact value depends on the subpolar surface temperature. Our results suggest the possibility of a negative feedback mechanism, unique to water planets, where a reduction in the subpolar temperature drives more CO2 into the atmosphere to increase the greenhouse effect.

  9. CdSeTe NSs/TiO2 NTs Photoelectric Catalytic Reduction of CO2%CdSeTe NSs/TiO2 NTs的制备及其光电催化还原CO2的应用

    Institute of Scientific and Technical Information of China (English)

    井华; 王祜英; 徐金凤; 睢晓娜; 胡海涛; 李培强; 尹洪宗

    2013-01-01

    reflection spectrum), it got the band gap of the as-prepared catalyst material, 1.48 eV. Processing XPS (X-ray photoelectron spectroscopy) data by Linear extrapolation, we got its valence band located at 1.02 eV. So we could deduce that the conduction band minimum (CBM) was located at -0.46 eV. Under light irradiation, the photoelectrocatalytic reduction performance for CO2 had a significant improvement compared with TiO2 NTs, it expressed as the great increase of reduction current density. In the photoelectrocatalytic reduction of CO2 process, methanol was the major product identified by gas chromatography, and the excellent reduction mechanism was explained from the following three aspects: energy band match, electron high transport ability and the stability of catalyst material.

  10. Nitrogen-doped TiO2 microsheets with enhanced visible light photocatalytic activity for CO2 reduction%氮自掺杂暴露(001)晶面TiO2微米片的可见光光催化CO2还原性能增强

    Institute of Scientific and Technical Information of China (English)

    Maxwell Selase Akple; 刘敬祥; 秦志扬; S. Wageh; Ahmed. A. Al-Ghamdi; 余家国; 刘升卫

    2015-01-01

    Nitrogen‐doped anatase TiO2 microsheets with 65%(001) and 35%(101) exposed faces were fab‐ricated by the hydrothermal method using TiN as precursor in the presence of HF and HCl. The samples were characterized by scanning electron microscopy, X‐ray diffraction, N2 adsorption, X‐ray photoelectron spectroscopy, UV‐visible spectroscopy, and electrochemical impedance spectroscopy. Their photocatalytic activity was evaluated using the photocatalytic reduction of CO2. The N‐doped TiO2 sample exhibited a much higher visible light photocatalytic activity for CO2 reduction than its precursor TiN and commercial TiO2 (P25). This was due to the synergistic effect of the formation of surface heterojunctions on the TiO2 microsheet surface, enhanced visible light absorption by nitro‐gen‐doping, and surface fluorination.%化石能源的使用可产生大量CO2,带来严重的温室效应。光催化CO2还原生产太阳燃料技术既有望缓解温室效应,又可以将低能量密度的太阳能转化为高能量密度的化学能储存起来方便使用。高效光催化材料的开发是发展光催化技术的关键。迄今,在已开发的所有半导体光催化材料中, TiO2仍是广泛研究的明星材料。在实际使用中, TiO2的光催化效率仍受限于其极弱的可见光利用率和较高的电子-空穴复合几率。近年来,越来越多的研究表明TiO2的结构与形貌特征极大地影响其光催化效率。尤其, TiO2的外露晶面设计与晶面效应研究引起了广泛关注。由于具有较高表面能和较多表面不饱和键,起初大多数理论和实验研究认为锐钛矿TiO2(001)晶面是光催化活性晶面。后来,越来越多研究表明并非锐钛矿TiO2(001)晶面的暴露比例越高其光催化活性就越高。最近,我们发现锐钛矿TiO2(001)晶面与(101)晶面在调控光催化CO2还原性能上具有良好的协同效应。密度泛函理论计算表明,锐钛矿TiO2的(001)晶面与(101)

  11. Double trouble: subsidence and CO2 respiration due to 1,000 years of Dutch coastal peatlands cultivation

    Science.gov (United States)

    Erkens, Gilles; van der Meulen, Michiel J.; Middelkoop, Hans

    2016-05-01

    Coastal plains are amongst the most densely populated areas in the world. Many coastal peatlands are drained to create arable land. This is not without consequences; physical compaction of peat and its degradation by oxidation lead to subsidence, and oxidation also leads to emissions of carbon dioxide (CO2). This study complements existing studies by quantifying total land subsidence and associated CO2 respiration over the past millennium in the Dutch coastal peatlands, to gain insight into the consequences of cultivating coastal peatlands over longer timescales. Results show that the peat volume loss was 19.8 km3, which lowered the Dutch coastal plain by 1.9 m on average, bringing most of it below sea level. At least 66 % of the volume reduction is the result of drainage, and 34 % was caused by the excavation and subsequent combustion of peat. The associated CO2 respiration is equivalent to a global atmospheric CO2 concentration increase of ~0.39 ppmv. Cultivation of coastal peatlands can turn a carbon sink into a carbon source. If the path taken by the Dutch would be followed worldwide, there will be double trouble: globally significant carbon emissions and increased flood risk in a globally important human habitat. The effects would be larger than the historic ones because most of the cumulative Dutch subsidence and peat loss was accomplished with much less efficient techniques than those available now.

  12. Photocatalytic Reduction of CO2 by CdS/C-TiO2 Composite Photocatalyst%CdS/C-TiO2复合光催化剂光催化还原CO2性能研究

    Institute of Scientific and Technical Information of China (English)

    李贤达; 单雯妍; 白雪峰

    2012-01-01

    A series of CdS/C-TiO2 photocatalysts were synthesized via precipitation-hydrothermal method. The crystal structure, morphology and photoelectric properties of above-prepared photocatalysts were characterized by X-ray diffraction (XRD), UV-Vis diffusive reflectance spectroscopy (DRS), field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy(XPS). The influences of quality ratio of citric acid (CA)/TiO2 on photocatalytic activity of CdS/C-TiO2 photocatalysts were investigated. The results demonstrated that C-doping had great effects on the crystal structure and micro-morphology. The photocatalytic activity was enhanced by doping; the highest yield of methanoic acid and methyl aldehyde in the catalytic reduction of CO2 reached 533u,mol/(g-h) when the quality ratio of CA to TiO2 was 3/1 under the irradiation of UV light.%采用沉淀-水热法制备了CdS/C-TiO2系列复合光催化剂,通过XRD、UV-Vis、FESEM、XPS等分析手段对催化剂晶体结构、形貌及光电性能进行了表征,考察了柠檬酸(CA)/TiO2质量比R对CdS/C-TiO2复合光催化剂光催化性能的影响.实验结果表明,碳掺杂影响催化剂的晶体结构及其微观形貌,掺杂后光催化活性显著提高.在紫外光照射下进行光催化还原CO2反应,当CA/TiO2质量比R=3/1时,催化活性最高,还原产物HCOOH和HCHO总收率达到533μmol/(g·h).

  13. Reducing CO2 emission from bitumen upgrading

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, John

    2011-07-15

    The treatment of sand oil can result in significant CO2 emission. Ceramatec Inc. has developed a technology to reduce the emission of CO2 during the upgrading of feedstocks bearing heteroatoms. This technology can be applied to kerogen derived oil (shale oil) and heavy oil as well as to bitumen from oil sands. Metallic sodium is used as the reducing and heteroatom scavenging agent. Hydrogen, methane or other hydrocarbons may be used to cap radicals formed in the process. But using methane can lead to lower material and capital costs, greater product yield, and lower CO2 emission. During the upgrading process, the aromatic constituents remain in the product, after treatment with sodium and removal of sulphur, nitrogen and metals. Aromatic saturation is not required with sodium, so less hydrogen is needed which leads to reduced CO2 emission. The reason is that CO2 is emitted in the steam methane reforming (SMR) process where hydrogen is produced. An example is introduced to demonstrate the reduction of CO2 emission from hydrogen production. Another advantage of the sodium/methane upgrading process is the incorporation of methane into the fuel. In addition, the total acid number, TAN, becomes negligible in the sodium upgrading processes. Ceramatec has also developed a process for the recovery of sodium from the sodium salts generated in the sodium/methane upgrading process.

  14. Kosten en baten CO2-emissiereductie maatregelen

    NARCIS (Netherlands)

    Daniels, B.; Tieben, B.; Weda, J.; Hekkenberg, M.; Smekens, K.; Vethman, P.

    2012-01-01

    The Dutch Ministry of Infrastructure and the Environment has requested the Energy Research Centre of the Netherlands (ECN) and SEO Economic Research (SEO) to investigate the costs and benefits of a broad range of technical measures to realise CO2 emission reductions. The research aims to identify th

  15. Effect Analysis of Furnace Slag Project of Bayi Steel to Reduction CO2 Emission in Xinjiang Region%八钢矿渣微粉项目对促进我区工业CO2减排的分析

    Institute of Scientific and Technical Information of China (English)

    李涛; 臧疆文

    2010-01-01

    CO2减排是我国实现清洁化生产中长期规划中的一项重要内容.通过论述矿渣微粉是实现CO2减排的主要途径,指出八钢建设矿渣微粉项目,不仅能够有效地降低八钢工业固体废弃物的排放和环境污染问题,而且对新疆工业CO2减排具有重要意义.

  16. A cost effective CO2 strategy

    DEFF Research Database (Denmark)

    by the Ministry of Transport, with the Technical University of Denmark as one of the main contributors. The CO2-strategy was to be based on the principle of cost-effectiveness. A model was set up to assist in the assessment. The model consists of a projection of CO2-emissions from road and rail modes from 2020...... are evaluated according to CO2 reduction potential and according to the ‘shadow price’ on a reduction of one ton CO2. The shadow price reflects the costs (and benefits) of the different measures. Comparing the measures it is possible to identify cost effective measures, but these measures are not necessarily......, a scenario-part and a cost-benefit part. Air and sea modes are not analyzed. The model adopts a bottom-up approach to allow a detailed assessment of transport policy measures. Four generic areas of intervention were identified and the likely effect on CO2 emissions, socioeconomic efficiency and other...

  17. Modern digital plain-radiography of the whole spine in scoliosis patients. Dose reduction and quality criteria; Moderne digitale Radiografie der Ganzwirbelsaeule bei Skoliose. Dosisreduktion und Qualitaetskriterien

    Energy Technology Data Exchange (ETDEWEB)

    Kloth, Jost Karsten; Stiller, W.; Kauczor, H.U.; Weber, M.A. [Universitaetsklinik Heidelberg (Germany). Diagnostische und Interventionelle Radiologie; Wiedenhoefer, B.; Ewerbeck, V. [Universitaetsklinik Heidelberg (Germany). Orthopaedische Universitaetsklinik; Burkholder, I. [StaBiL, Statistische und Biometrische Loesungen, Zweibruecken (Germany)

    2013-01-15

    To reduce the radiation exposure of plain radiographs of the entire spine depending on specific indications, since these are frequently performed examinations of children and young adults with scoliosis and to determine objective quality control criteria to ensure accurate assessment. In this prospective randomized study 323 patients underwent plain-radiography of the entire spine with standard and 50 % reduced dose. In an experimental pilot-study this target-dose was determined using an Alderson-Phantom. The evaluation of the experimental radiographs, as well as, the randomized plain-radiographs was conducted using the following criteria: endplates (Cobb-angle), spinal process and pedicel (rotation), lateral margin of the vertebral body (lateral alignment), identification of C7 / S1 (perpendicular). Two radiologists evaluated these criteria using a score ranging from 1 (definitely assessable) to 4 (not assessable). If one single criteria was evaluated with a score of 3 or more points or more than 2 criteria with 2 points, the radiograph was scored as ''not assessable''. The statistical analysis was conducted as a non-inferiority-trial. Seven (2.4 %) of the 290 examined x-rays were scored as not assessable. There was no statistic inferiority between the examinations with standard or reduced dose, while singular assessment of the defined criteria was likewise dose-independent. Plain-radiography of the total spine in patients with scoliosis can be performed with a dose reduction of 50 % without a loss of validity. The obtained quality control criteria were clinically applicable. (orig.)

  18. CO2-adapted legumes ameliorate but do not prevent the negative effect of elevated CO2 on nitrogen fixation

    Science.gov (United States)

    Newton, P.; Bowatte, S.; Lieffering, M.; Li, F.

    2015-12-01

    The response of biological nitrogen fixation (BNF) to climate and elevated CO2 (eCO2) is a key uncertainty in modelling C cycle projections. In addition, as BNF provides 50% of the nitrogen (N) input to agricultural production and as ecosystem responses to eCO2 are strongly influenced by N availability then the eCO2 impact on BNF is central to modelling legume-based system responses to climate change. Greater photoassimilate production under eCO2 should lead to enhanced BNF and this response is a feature of ecosystem models thus providing the N inputs necessary to provide continuing stimulation of NPP. FACE experiments provide a 'realistic' environment for eCO2 studies; however, even if run for multiple years, they still may not capture adaptation to eCO2 particularly in ecosystems dominated by perennial species. We tested the effect of eCO2 on BNF and the potential importance of adaption by growing legumes that had been exposed to high or ambient CO2 concentrations at a natural CO2 spring in a long-running (16 year) FACE experiment on grassland. BNF was significantly lower under eCO2 but the reduction was less marked where plants had originated in a high CO2 environment. An ecosystem model run with reduced BNF proved a better fit to the experimental data for the FACE experiment than where BNF was enhanced or unchanged under eCO2.

  19. Synthesis of Supported TiO2/SBA-15 Catalysts and Their Performance on Photocatalytic Reduction of CO2%负载型TiO2/SBA-15的制备及其光催化还原CO2性能

    Institute of Scientific and Technical Information of China (English)

    王会香; 姜东; 吴东; 李德宝; 孙予罕

    2012-01-01

    the highly disper- sion Of TiO2 on SBA-15. The obtained TiO2/SBA-15 catalysts have been characterized by X-ray diffraction (XRD), Raman spectrum, Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), nitrogen adsorption and UV-Visible diffuse reflectance spectroscopy (UV-Vis). Above results indicate that the TiO2/SBA-15 catalysts exhibit large specific surface area and TiO2 on SBA-15 supporter is anatase phase, they are both play important roles in photocata- lytic application. In the current manuscript, the photocatalytic reduction of CO2 under UV light irradiation as a prober reac- tion was used to investigate the photocatalytic performance of TiO2/SBA-15 catalysts. It was found that the obtained catalysts performed high photocatalytic capacity for CO2 reduction, especially when the loading amount of TiO2 was around 16.5 wt% [n(COOH)/n(TB)=3], the methanol production got maximum which could reach 80 gmol/g-catalyst after 6 h UV light irra- diation. Compared with the catalysts which synthesized through simple impregnation method, our TiO2/SBA-15 catalysts showed the higher activity in photocatalytic reduction of CO2, owing to the better dispersion and crystallization.

  20. A cost effective CO2 strategy

    DEFF Research Database (Denmark)

    , a scenario-part and a cost-benefit part. Air and sea modes are not analyzed. The model adopts a bottom-up approach to allow a detailed assessment of transport policy measures. Four generic areas of intervention were identified and the likely effect on CO2 emissions, socioeconomic efficiency and other...... concerns of the potential measures within those intervention areas: • Reductions in the need to travel • Improved efficiency of the transport system • Improved fuel efficiency of transport activities • Reduced CO2 intensity of the fuels Within each area a number of measures were analysed. The measures...

  1. Toxic emissions and devaluated CO2-neutrality

    DEFF Research Database (Denmark)

    Czeskleba-Dupont, Rolf

    with a climate policy whose goals of CO2-reduction were made operational by green-wash. Arguments are given for the devaluation of CO2- neutrality in case of burning wood. Alternative practices as storing C in high quality wood products and/or leaving wood in the forest are recommended. A counter......-productive effect of dioxin formation in the cooling phase of wood burning appliances has been registered akin to de-novo-synthesis in municipal solid waste incinerators. Researchers, regulators and the public are, however, still preoccupied by notions of oven design and operation parameters, assuming that dioxin...

  2. Forecasting global atmospheric CO2

    Directory of Open Access Journals (Sweden)

    A. Agustí-Panareda

    2014-05-01

    Full Text Available A new global atmospheric carbon dioxide (CO2 real-time forecast is now available as part of the pre-operational Monitoring of Atmospheric Composition and Climate – Interim Implementation (MACC-II service using the infrastructure of the European Centre for Medium-Range Weather Forecasts (ECMWF Integrated Forecasting System (IFS. One of the strengths of the CO2 forecasting system is that the land surface, including vegetation CO2 fluxes, is modelled online within the IFS. Other CO2 fluxes are prescribed from inventories and from off-line statistical and physical models. The CO2 forecast also benefits from the transport modelling from a state-of-the-art numerical weather prediction (NWP system initialized daily with a wealth of meteorological observations. This paper describes the capability of the forecast in modelling the variability of CO2 on different temporal and spatial scales compared to observations. The modulation of the amplitude of the CO2 diurnal cycle by near-surface winds and boundary layer height is generally well represented in the forecast. The CO2 forecast also has high skill in simulating day-to-day synoptic variability. In the atmospheric boundary layer, this skill is significantly enhanced by modelling the day-to-day variability of the CO2 fluxes from vegetation compared to using equivalent monthly mean fluxes with a diurnal cycle. However, biases in the modelled CO2 fluxes also lead to accumulating errors in the CO2 forecast. These biases vary with season with an underestimation of the amplitude of the seasonal cycle both for the CO2 fluxes compared to total optimized fluxes and the atmospheric CO2 compared to observations. The largest biases in the atmospheric CO2 forecast are found in spring, corresponding to the onset of the growing season in the Northern Hemisphere. In the future, the forecast will be re-initialized regularly with atmospheric CO2 analyses based on the assimilation of CO2 satellite retrievals, as they

  3. HyGenSys: a Flexible Process for Hydrogen and Power Production with Reduction of CO2 Emission HyGenSys : un procédé flexible de production d’hydrogène et d’électricité avec réduction des émissions de CO2

    Directory of Open Access Journals (Sweden)

    Giroudière F.

    2010-09-01

    Full Text Available This paper presents the latest development of HyGenSys, a new sustainable process and technology for the conversion of natural gas to hydrogen and power. The concept combines a specific steam reforming reactor-exchanger with a gas turbine. The heat necessary for the steam reforming reaction comes from hot pressurized flue gases produced in a gas turbine instead of a conventional furnace. Thanks to this high level of heat integration, the overall efficiency is improved and the natural gas consumption is reduced which represents an advantage with regard to economics and CO2 emission reduction. In addition to the efficient HyGenSys process scheme itself, the technology of the reactorexchanger also offers a high level of heat integration for even more energy saving. Two main alternatives are examined in order to meet two different requirements. The first one, named HyGenSys-0, focuses on the hydrogen production for the refining and petrochemical application. The second one named HyGenSys-1, concerns the centralized power production with pre-combustion CO2capture. In that case, the produced hydrogen is fully used to fuel a power gas turbine. HyGenSys-1 has been developed and optimised in CACHET, a European Community funded project. The CACHET electrical power objective was 400 MW at the minimum. HyGenSys-0 and HyGenSys-1 are described in detail with challenges and advantages compared to existing technologies. For both alternatives, the heart of the technology is the reactor-exchanger. The reactor-exchanger design relies on an innovative arrangement of bayonet tubes that allows, at large scale, multiple heat exchanges between hot pressurized flue gas, natural gas feed and hydrogen rich stream produced. Cet article présente les développements récents d’HyGenSys, nouvel éco-procédé de conversion du gaz naturel en hydrogène et électricité. Le concept combine un réacteur-échangeur spécifique de reformage à la vapeur avec une turbine à gaz

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

    Science.gov (United States)

    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

  5. India Co2 Emissions

    Science.gov (United States)

    Sharan, S.; Diffenbaugh, N. S.

    2010-12-01

    created a balance in between the “developed” and developing countries. If India was producing the same amounts of emissions per capita as the it would have a total of 20 billion metric tons of CO2 emissions annually.

  6. CO2 as a refrigerant

    CERN Document Server

    2014-01-01

    A first edition, the IIR guide “CO2 as a Refrigerant” highlights the application of carbon dioxide in supermarkets, industrial freezers, refrigerated transport, and cold stores as well as ice rinks, chillers, air conditioning systems, data centers and heat pumps. This guide is for design and development engineers needing instruction and inspiration as well as non-technical experts seeking background information on a specific topic. Written by Dr A.B. Pearson, a well-known expert in the field who has considerable experience in the use of CO2 as a refrigerant. Main topics: Thermophysical properties of CO2 – Exposure to CO2, safety precautions – CO2 Plant Design – CO2 applications – Future prospects – Standards and regulations – Bibliography.

  7. CO2 utilization: Developments in conversion processes

    Directory of Open Access Journals (Sweden)

    Erdogan Alper

    2017-03-01

    The potential utilization of CO2, captured at power plants, should also been taken into consideration for sustainability. This CO2 source, which is potentially a raw material for the chemical industry, will be available at sufficient quality and at gigantic quantity upon realization of on-going tangible capture projects. Products resulting from carboxylation reactions are obvious conversions. In addition, provided that enough supply of energy from non-fossil resources, such as solar [1], is ensured, CO2 reduction reactions can produce several valuable commodity chemicals including multi-carbon compounds, such as ethylene and acrylic acid, in addition to C1 chemicals and polymers. Presently, there are only few developing technologies which can find industrial applications. Therefore, there is a need for concerted research in order to assess the viability of these promising exploratory technologies rationally.

  8. Photocatalytic Reduction of CO2 with H2O on Pt(Cu)-CdS/Titanate Nanotube%Pt(Cu)-CdS/钛酸纳米管光催化转化CO2和H2O的研究

    Institute of Scientific and Technical Information of China (English)

    张传照; 陈威; 李曹龙; 贺学智; 袁坚; 上官文峰

    2011-01-01

    Titanate nanotube (TINT) was made from commercial titanium dioxide powder (P25, Degussa) through hydrothermal- ultrasonic method. Then CdS combined TiNT was prepared via simple ion exchange. Co-catalyst Pt or Cu was loaded by wet impregnation method. The photocatalytic reduction of CO2 and H2O vapor on the catalysts was investigated at room temperature and atmospheric pressure. The morphology, crystal structure, photon absorption property and surface area of synthesized samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-Vis DRS and BET, etc. The experiment result shows that the specific surface area of titanate nanotube is 274.6 m^2/g, which is 4 times more than that of P25. The main photocatalytie products on CdS/TiNT are carbon monoxide and methane. After loaded with Pt or Cu, the yield of carbon monoxide (0.32 umol · h^- · gTi^ -1 ) is almost 1. 5 times of the yield of CdS/TiNT and the yield of methane(0.13 umol · h^- · gTi^ -1 ) is increased about 3 times compared with that of samples without Pt or Cu loading.%以商业P25为前躯体,用强碱水热超声法合成钛酸纳米管(TiNT),以其为载体采用离子交换法制备CdS复合钛酸纳米管(CdS/TiNT),再用浸渍法负载共催化剂Pt或Cu.对上述样品进行光催化转化CO2和H2O的实验研究,并采用透射电子显微镜(TEM)、X射线衍射(XRD)、紫外可见漫反射(UV—Vis DRS)、比表面分析(BET)等测试方法对催化剂的形貌、晶相、吸光性和比表面等物理性能进行表征.结果表明:钛酸纳米管TiNT的比表面积达到274.6m^2/g,为P25的四倍多.经CdS复合后的CdS/TiNT剂具有可见光响应.光催化转化二氧化碳和水蒸气的主要产物为CO和CH4,负载Pt或Cu后的Pt(Cu)-CdS/TiTNT其CO的产率(0.32μmol·h^-1·g^-1)是负载前的1.5倍,CH4的产率(0.13μmol·h~·g^-1)则提升了近3倍.

  9. 2020年我国钢铁行业C02排放趋势和减排路径分析%Analysis on CO2 Emission Trend and Emission Reduction Path of China's Steel and Iron Industry in 2020

    Institute of Scientific and Technical Information of China (English)

    袁敏; 康艳兵; 刘强; 赵盟

    2012-01-01

    我国钢铁行业CO2排放占全国排放总量的近20%,分析钢铁行业的CO2排放趋势和减排路径对我国控制温室气体排放有着重要的现实意义.本文从影响钢铁行业排放的主要影响因素着手,分析了钢铁产量和工序能耗的现状及未来发展趋势,测算了2010 -2020年钢铁行业排放趋势和减排潜力,同时给出了减排途径和各种减排措施的贡献度,并提出了相关政策建议.%CO2 emission from China's steel and iron industry accounts for nearly 20% of total national emissions. Analysis on CO2 emission trend and emission reduction path of steel and iron industry is significant to control CO2 emissions in China. From the perspective of major influencing factors, this paper analyzes the status and future trend of steel and iron production and energy consumption per unit of product, calculates historical and future emissions as well as emission reduction potentials, and also analyzes reduction paths and contributions of various reduction measures, finally proposes appropriate policy recommendations.

  10. Reducing CO2 from shipping – do non-CO2 effects matter?

    Directory of Open Access Journals (Sweden)

    M. S. Eide

    2013-04-01

    Full Text Available Shipping is a growing sector in the global economy, and it contributions to global CO2 emissions are expected to increase. CO2 emissions from the world shipping fleet will likely be regulated in the near future, and studies have shown that significant emission reductions can be achieved at low cost. Regulations are being discussed for both existing ships as well as for future additions to the fleet. In this study a plausible CO2 emission reduction inventory is constructed for the cargo fleet existing in 2010, as well as for container ships, bulk ships and tankers separately. In the reduction inventories, CO2 emissions are reduced by 25–32% relative to baseline by applying 15 technical and operational emission reduction measures in accordance with a ship-type-specific cost-effectiveness criterion, and 9 other emission compounds are changed as a technical implication of reducing CO2. The overall climate and environmental effects of the changes to all 10 emission components in the reduction inventory are assessed using a chemical transport model, radiative forcing (RF models and a simple climate model. We find substantial environmental and health benefits with up to 5% reduction in surface ozone levels, 15% reductions in surface sulfate and 10% reductions in wet deposition of sulfate in certain regions exposed to heavy ship traffic. The major ship types show distinctly different contributions in specific locations. For instance, the container fleet contributes 50% of the sulfate decline on the west coast of North America. The global radiative forcing from a 1 yr emission equal to the difference between baseline and reduction inventory shows an initial strong positive forcing from non-CO2 compounds. This warming effect is due to reduced cooling by aerosols and methane. After approximately 25 yr, the non-CO2 forcing is balanced by the CO2 forcing. For the global mean temperature change, we find a shift from warming to cooling after approximately 60

  11. Reducing CO2 from shipping - do non-CO2 effects matter?

    Science.gov (United States)

    Eide, M. S.; Dalsøren, S. B.; Endresen, Ø.; Samset, B.; Myhre, G.; Fuglestvedt, J.; Berntsen, T.

    2013-04-01

    Shipping is a growing sector in the global economy, and it contributions to global CO2 emissions are expected to increase. CO2 emissions from the world shipping fleet will likely be regulated in the near future, and studies have shown that significant emission reductions can be achieved at low cost. Regulations are being discussed for both existing ships as well as for future additions to the fleet. In this study a plausible CO2 emission reduction inventory is constructed for the cargo fleet existing in 2010, as well as for container ships, bulk ships and tankers separately. In the reduction inventories, CO2 emissions are reduced by 25-32% relative to baseline by applying 15 technical and operational emission reduction measures in accordance with a ship-type-specific cost-effectiveness criterion, and 9 other emission compounds are changed as a technical implication of reducing CO2. The overall climate and environmental effects of the changes to all 10 emission components in the reduction inventory are assessed using a chemical transport model, radiative forcing (RF) models and a simple climate model. We find substantial environmental and health benefits with up to 5% reduction in surface ozone levels, 15% reductions in surface sulfate and 10% reductions in wet deposition of sulfate in certain regions exposed to heavy ship traffic. The major ship types show distinctly different contributions in specific locations. For instance, the container fleet contributes 50% of the sulfate decline on the west coast of North America. The global radiative forcing from a 1 yr emission equal to the difference between baseline and reduction inventory shows an initial strong positive forcing from non-CO2 compounds. This warming effect is due to reduced cooling by aerosols and methane. After approximately 25 yr, the non-CO2 forcing is balanced by the CO2 forcing. For the global mean temperature change, we find a shift from warming to cooling after approximately 60 yr. The major ship

  12. 1998 investigation report. Basic investigation for promotion of joint projects, 'Investigation on Russian CO2 reduction conditions'; 1998 nendo Roshiakoku CO{sub 2} sakugen anken chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    A feasibility study was conducted for a project assuming modernization of a manufacturing plant and improvement of power generation facilities in Russia, with the aim of 'joint implementation' in reducing the greenhouse effect gas by utilizing technologies mutually between advanced nations. The project is to replace obsolete an open hearth furnace and cupola with electric furnaces in connection with the cast steel and forged steel production facilities of Uralmash, a largest-scale Russian heavy machinery manufacturer, to change surface hardening equipment for rolling roll products from a combustion method to a low frequency induction heating method, and to enhance efficiency of the power generation equipment of a public corporation which supplies electric power to Uralmash. Through a field study and a technological investigation, the social background of the project was examined such as the situation of the Russian Federation, its environment and the present state of Sveldorv province; then, examined were the specifications of the facilities, project cost, cost performance, CO2 reduction expected, environmental influence, etc., in the case where the modernization project of Uralmash was implemented. (NEDO)

  13. Regional Allocation of CO2 Intensity Reduction Targets Based on Cluster Analysis%基于聚类分析的碳强度目标分解研究

    Institute of Scientific and Technical Information of China (English)

    杨源; 蔡闻佳; 王灿; 王思强

    2012-01-01

    基于地区聚类分析得到了我国2020年碳强度目标分解方案.根据各地区在经济能力、排放水平和减排潜力上的相似程度,将我国30个省区分成6类.按照公平原则,经济最发达的第1、2类地区减排目标最高,分别为55%和65%,但是其减排潜力较小;按照效率原则,减排潜力较大的第3、5类地区减排目标最高,分别为48%和61%,但是其经济相对落后;综合分解方案显示减排潜力最大的第5类地区,以及属于工业与排放大省的第2,3类地区的减排目标最高,分别为54%、49%和49%.而在这3种分解方案下,经济能力、排放水平与减排潜力都较低的第4类与第6类地区减排指标最高不超过40%.经济能力与减排潜力在空间上存在一定程度的错位,导致仅通过碳强度目标的分解无法较好地兼顾公平与效率,还需要建立配套的市场机制和政策工具.%To meet China's CO2 intensity target of 40%-45% reduction by 2020 from 2005 level, a regional allocation method based on cluster analysis was developed. The 30 provinces were classified into 6 groups based on economy, emission and reduction potential indicators. Under equity principle, the two most developed groups are assigned the highest reduction targets (55% and 65% respectively), however their reduction potential is limited. Under efficiency principle, the 2 groups with highest reduction potential take the highest targets (48% and 61% respectively), but their economy is relatively backward. When equity and efficiency are equally weighted, the 5th group with prominent reduction potential takes the highest target (54%), and the 2nd and 3rd groups with large industry scale take the second highest target (49%). Whereas under the 3 allocation schemes, the targets are not greater than 40% for the 4th and 6th group, which have relatively low economic ability, emission and reduction potential. Due to inconsistency between economic ability and reduction

  14. CO2 emission benefit of diesel (versus gasoline) powered vehicles.

    Science.gov (United States)

    Sullivan, J L; Baker, R E; Boyer, B A; Hammerle, R H; Kenney, T E; Muniz, L; Wallington, T J

    2004-06-15

    Concerns regarding global warming have increased the pressure on automobile manufacturers to decrease emissions of CO2 from vehicles. Diesel vehicles have higher fuel economy and lower CO2 emissions than their gasoline counterparts. Increased penetration of diesel powered vehicles into the market is a possible transition strategy toward a more sustainable transportation system. To facilitate discussions regarding the relative merits of diesel vehicles it is important to have a clear understanding of their CO2 emission benefits. Based on European diesel and gasoline certification data, this report quantifies such CO2 reduction opportunities for cars and light duty trucks in today's vehicles and those in the year 2015. Overall, on a well-to-wheels per vehicle per mile basis, the CO2 reduction opportunity for today's vehicles is approximately 24-33%. We anticipate that the gap between diesel and gasoline well-to-wheel vehicle CO2 emissions will decrease to approximately 14-27% by the year 2015.

  15. Study of Photocatalytic Reduction of CO2 with H2O Vapor on CuOx/TiO2%CuOx/TiO2光催化水蒸气还原CO2反应研究

    Institute of Scientific and Technical Information of China (English)

    洪益娟; 张钦辉; 于建国

    2011-01-01

    以商品TiO-P25为原料,通过浸渍法负载一定量过渡金属Cu,得到一系列不同含量的CuO/TiO光催化剂.利用X射线衍射(XRD),X-射线光电子能谱(XPS),BET,高分辨率透射镜(HRTEM),X射线荧光光谱(XRF)和光致发光光谱(PL)等方法对催化剂进行了详细表征,在自建的光催化反应器中评价了气态水光催化还原CO反应的活性和CH收率.结果表明负载CuO后的TiO纳米材料光催化性能显著提高,其中1%CuO/TiO样品紫外光照72 h后,CH生成量达到了24.86 μmd·gn.同时,CuO负载量、反应温度、反应时间等因素对CH收率均有显著影响.%Using TiO2-P25 as a main material, CuOx loaded TiO2-P25 photocatalysts were prepared via wet impregnation method. The catalysts were characterized with powder X-Ray Diffraction (XRD), XPS, BET, High-Resolution Transmission Electron Microscopy (HRTEM), X-Ray Fluorescence Spectrometry (XRF) and photoluminescence (PL). The photoactivity of the catalysts was tested by photocatalytic reduction of CO2 with H2O vapor to produce chemically valuable compound including CH4 in self-build experimental set up. The experiment results suggested that the photocatalytic activity of TiO2 was improved remarkably with the loading of CuOx on the catalyst surface. The CH4 yield on 1% CuOx/TiO2 reached 24.86 mol · gTi-1 after 72 h UV irradiation, and the CuOx loading amount, the reaction temperature, reaction time also had great effect on CH4 yield.

  16. Particulate matters emitted from maize straw burning for winter heating in rural areas in Guanzhong Plain, China: Current emission and future reduction

    Science.gov (United States)

    Sun, Jian; Shen, Zhenxing; Cao, Junji; Zhang, Leiming; Wu, Tingting; Zhang, Qian; Yin, Xiuli; Lei, Yali; Huang, Yu; Huang, R.-J.; Liu, Suixin; Han, Yongming; Xu, Hongmei; Zheng, Chunli; Liu, Pingping

    2017-02-01

    Maize straw smoldering in "Heated Kang" is the traditional way for heating in winter in rural areas of Guanzhong Plain. This smolder procedure produced large quantities of pollutants and got more and more concern from both public and researchers. In this study, on-site measurements of straw smoldering in a residence with a Chinese 'Heated Kang' (Scenario 1) were done to determine the emissions factors (EFs) for pollutants. Moreover, EFs of pollutants from an advanced stove fired with maize straw (Scenario 2) and maize-straw pellet (Scenario 3) had been conducted in a laboratory to find the new measure to reduce the pollution emissions. The results showed that the EFs of PM2.5 for three scenarios were 38.26 ± 13.94 g·kg- 1, 17.50 ± 8.29 g·kg- 1 and 2.95 ± 0.71 g·kg- 1, respectively. Comparing EFs of pollutants from 3 scenarios indicates that both briquetting of straw and advanced stove with air distribution system could efficiently reduce pollutants emission especially for Scenario 3. In detail, EFs of PM2.5, OC, EC and water soluble ions all have over 90% reduction between Scenarios 1 and 3. All particle-size distributions were unimodal, and all peaked in particle sizes advanced stoves for residential heating could reduce PM2.5 emission from 48.3 Gg to 3.59 Gg, OC from 19.0 Gg to 0.91 Gg, EC from 1.7 Gg to 0.17 Gg and over 90% reduction on total water soluble ions in the whole region. A box model simulation for the Guanzhong Plain indicated that this conversion would lead to a 7.7% reduction in PM2.5 (from 130 to 120 μg·m- 3) in normal conditions and a 14.2% reduction (from 350 to 300 μg·m- 3) in hazy conditions. The results highlighted that the straw pellets burning in advanced stove can effectively reduce pollutants emitted and improve the energy use efficiency in comparison with maize straw smoldering in "Heated Kang". The study supplies an effective measure to reduce the rural biomass burning emission, and this method can be used in not only Guanzhong

  17. Estimado de la reducción de la emisión de co2 por accione de ahorro de electricidad en las condiciones de Cuba;Estimation of reduction of CO2 emission by electric power saving project in the Cuba conditions

    Directory of Open Access Journals (Sweden)

    Irina Salazar - Fonseca et all.

    2010-11-01

    Full Text Available Este trabajo expone los resultados del estudio realizado a las numerosas vías que existen para el cálculo del factor de emisión de CO2 a nivel mundial. A partir de una amplia búsqueda de información, se obtuvo la metodología propuesta para el cálculo del factor de emisión de CO2 para proyectos de ahorro de energía eléctrica, teniendo en cuenta las particularidades de la matriz energética del país en cuestión. La metodología propuesta es el resultado de las modificaciones realizadas a la metodología ACM 0002, que es la aprobada por la Junta Ejecutiva del Mecanismo de Desarrollo Limpio (MDL. A partir de los datos reales del consumo de combustible para la electricidad en Cuba en los años 2007 y 2008, se calcula el factor de emisión de CO2, obteniéndose un valor igual a 0,795 y 0,794 t CO2/MWh, respectivamente. Estos resultados evidencian el paulatino desarrollo hacia fuentes de energía mas limpias que se ha realizado en ese periodo en el país, caracterizado por la entrada en funcionamiento de varios emplazamientos de Fuel-oil.This work exposes result of accomplished study to the many manners that exist for the calculation of CO2 emission factor in the world. Latter a ample quest of information, the proposed methodology was obtained for calculation of CO2 emission factor for electric power saving project, taking the particularities of electrical systems into account country. The proposed methodology is results of modifications realized to the methodology ACM 0002, this are the approved in Executive Board of the Clean Development Mechanism (CDM. Whit the real data of fuel consumption for the electricity in Cuba in the years 2007 and 2008, CO2 emission factor is calculated, obtained an equal value to 0.795 and 0.794 tCO2/MWh, respectively. These aftermath evidence the gradual development to cleaning sources of energy that success in period at the country, characterized for the entrance in functioning of several Fuel

  18. CO2 storage capacity estimation: Methodology and gaps

    Science.gov (United States)

    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

  19. Reaction Mechanisms for the Electrochemical Reduction of CO2 to CO and Formate on the Cu(100) Surface at 298K from Quantum Mechanics Free Energy Calculations with Explicit Water.

    Science.gov (United States)

    Cheng, Tao; Xiao, Hai; Goddard, William A

    2016-10-11

    Copper is the only elemental metal that reduces a significant fraction of CO2 to hydrocarbons and alcohols, but the atomistic reaction mechanism that controls the product distributions are not known because it has not been possible to detect the reaction intermediates on the electrode surface experimentally, or carry out Quantum Mechanics (QM) calculations with a realistic description of the electrolyte (water). Here, we carry out Quantum Mechanics (QM) calculations with an explicit description of water on the Cu(100) surface (experimentally shown to be stable under CO2RR conditions) to examine the initial reaction pathways to form CO and formate (HCOO(-)) from CO2 through free energy calculations at 298K and pH 7. We find that CO formation proceeds from physisorbed CO2 to chemisorbed CO2 (*CO2(δ-)), with a free energy barrier of ΔG(‡)=0.43 eV, the rate determining step (RDS). The subsequent barriers of protonating *CO2(δ-) to form COOH* and then dissociating COOH* to form *CO are 0.37 eV and 0.30 eV, respectively. HCOO(-) formation proceeds through a very different pathway in which physisorbed CO2 reacts directly with a surface H* (along with electron transfer), leading to ΔG(‡) = 0.80 eV. Thus, the competition between CO formation and HCOO(-) formation occurs in the first electron transfer step. On Cu(100), the RDS for CO formation is lower, making CO the predominant product. Thus, to alter the product distribution we need to control this first step of CO2 binding, which might involve alloying or changing the structure at the nanoscale.

  20. Enzymes in CO2 Capture

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Gladis, Arne; Thomsen, Kaj

    of carbon capture is the application of enzymes for acceleration of typically slow ternary amines or inorganic carbonates. There is a hidden potential to revive currently infeasible amines which have an interesting low energy consumption for regeneration but too slow kinetics for viable CO2 capture. The aim......The enzyme Carbonic Anhydrase (CA) can accelerate the absorption rate of CO2 into aqueous solutions by several-fold. It exist in almost all living organisms and catalyses different important processes like CO2 transport, respiration and the acid-base balances. A new technology in the field...... of this work is to discuss the measurements of kinetic properties for CA promoted CO2 capture solvent systems. The development of a rate-based model for enzymes will be discussed showing the principles of implementation and the results on using a well-known ternary amine for CO2 capture. Conclusions...

  1. CO2 Sequestration short course

    Energy Technology Data Exchange (ETDEWEB)

    DePaolo, Donald J. [Lawrence Berkeley National Laboratory; Cole, David R [The Ohio State University; Navrotsky, Alexandra [University of California-Davis; Bourg, Ian C [Lawrence Berkeley National Laboratory

    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).

  2. Photocatalytic Reduction of CO2 over Sulfied-Loaded ZnO/ZnAl2O4 Composite Hollow Sphere%硫化物负载ZnO/ZnAl2O4复合空心球及其光催化还原CO2

    Institute of Scientific and Technical Information of China (English)

    张丽; 张秀秀; 戴超华; 欧阳杰; 阎建辉

    2016-01-01

    ZnO/ZnAl2O4 nanocomposites were successfully synthetized by a facile one-pot hydrothermal process. CuS, CdS and Bi2S3 were loaded on the ZnO/ZnAl2O4by an impregnation process to investigate their photocatalytic activi-ties under simulated sunlight irradiation. The as-prepared samples were characterized by XRD, SEM, TEM, BET and FLtechniques. Meanwhile, photocatalytic reduction of CO2 from water over the samples was explored using NaOH and Na2SO3 as sacrificial reagents.The effects of the type and the amount of sulfideson photocatalytic reduction effi-ciency were investigated. The results indicated that Bi2S3-loading lowered down the photocatalytic activity of ZnO/ZnAl2O4, while CuS or CdS loading enhanced the photocatalytic activity. After ZnO/ZnAl2O4 loaded with 1wt% CuS, the maximum yield of 8.21 mmol/gcat methanol within 6 h was obtained, which increased by up to 3.2 times as compared to ZnO/ZnAl2O4under the same conditions. The photocatalytic mechanism of the as-prepared CuS/ZnO/ZnAl2O4were preliminarily discussed.%采用一步水热法制备了ZnO/ZnAl2O4纳米复合物,通过浸渍法负载CuS、CdS和Bi2S3对其进行修饰,并在模拟太阳光照射下研究负载样品的光催化活性。用XRD、SEM、TEM、BET和FL等技术对所得样品进行表征,以NaOH 和Na2SO3作为光催化还原二氧化碳过程的牺牲剂,考察了硫化物种类及其负载量对ZnO/ZnAl2O4光催化还原活性的影响。结果表明,负载CuS和CdS均可提高ZnO/ZnAl2O4光催化还原活性,而负载Bi2S3却有所降低。当CuS负载量为1wt%时,样品光催化还原活性最佳,反应6 h后所得还原产物甲醇的生成量为8.21 mmol/gcat,在相同条件下较原样提高了约3.2倍。对CuS/ZnO/ZnAl2O4的光催化机理进行了初步探讨。

  3. Adsorption of CO2 by alginate immobilized zeolite beads

    Science.gov (United States)

    Suratman, A.; Kunarti, E. S.; Aprilita, N. H.; Pamurtya, I. C.

    2017-03-01

    Immobilized zeolit in alginate beads for adsorption of CO2 was developed. Alginate immobilized zeolit beads was generated by dropping the mixture of Na-alginate and zeolite solution into Ca2+ solution. The adsorption efficacy such as the influence of contact time, mass of zeolite, flowrate of CO2, and mass of adsorbent was evaluated. The adsorption of CO2 onto alginate immobilized zeolit beads was investigated by performing both equilibrium and kinetic batch test. Bead was characterized by FTIR and SEM. Alginate immobilized zeolit beads demonstrated significantly higher sorption efficacy compared to plain alginate beads and zeolite with 0.25 mmol CO2 adsorbed /g adsorbent. Optimum condition was achieved with mass composition of alginate:zeolite (3:1), flowrate 50 mL/min for 20 minutes. The alginate immobilized zeolit beads showed that adsorption of CO2 followed Freundlich isotherm and pseudo second order kinetic model. Adsorption of CO2 onto alginate immobilized zeolite beads is a physisorption with adsorption energy of 6.37 kJ/mol. This results indicates that the alginate immobilized zeolit beads can be used as promising adsorbents for CO2.

  4. Geothermal energy combined with CO2 sequestration: An additional benefit

    NARCIS (Netherlands)

    Salimi, H.; Wolf, K.H.A.A.; Bruining, J.

    2012-01-01

    In this transition period from a fossil-fuel based society to a sustainable-energy society, it is expected that CO2 capture and subsequent sequestration in geological formations plays a major role in reducing greenhouse gas emissions. An alternative for CO2 emission reduction is to partially replace

  5. CO2 Abatement In The Iron And Steel Industry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-01-15

    The iron and steel industry is the largest industrial source of CO2 emissions due to the energy intensity of steel production, its reliance on carbon-based fuels and reductants, and the large volume of steel produced -- over 1414 Mt in 2010. With the growing concern over climate change, steel makers are faced with the challenge of finding ways of lowering CO2 emissions without seriously undermining process efficiency or considerably adding to costs. This report examines ways of abating CO2 emissions from raw materials preparation (coking, sintering and pelletising plants) through to the production of liquid steel in basic oxygen furnaces and electric arc furnaces. Direct reduction and smelting reduction processes are covered, as well as iron making in a blast furnace. A range of technologies and measures exist for lowering CO2 emissions including minimising energy consumption and improving energy efficiency, changing to a fuel and/or reducing agent with a lower CO2 emission factor (such as wood charcoal), and capturing the CO2 and storing it underground. Significant CO2 reductions can be achieved by combining a number of the available technologies. If carbon capture and storage is fitted than steel plants could become near zero emitters of CO2.

  6. Geothermal energy combined with CO2 sequestration: An additional benefit

    NARCIS (Netherlands)

    Salimi, H.; Wolf, K.H.A.A.; Bruining, J.

    2012-01-01

    In this transition period from a fossil-fuel based society to a sustainable-energy society, it is expected that CO2 capture and subsequent sequestration in geological formations plays a major role in reducing greenhouse gas emissions. An alternative for CO2 emission reduction is to partially replace

  7. Costs, safety and uncertainties of CO2 infrastructure development

    NARCIS (Netherlands)

    Knoope, M.M.J.

    2015-01-01

    To avoid drastic climate change, strong reductions in CO2 emissions are required. Carbon capture and storage (CCS) is a potential mitigation measure. With CCS, CO2 from industrial and energy related sources is captured from flue gases and subsequently transported with pipelines and / or ships to geo

  8. Photocatalytic Reduction of CO2 over TiO2 Nanotube Arrays Covered with Si Thin Film%TiO2纳米管阵列覆盖Si薄膜光催化还原CO2性能的研究

    Institute of Scientific and Technical Information of China (English)

    刘有松; 张斌; 朱蕾; 常晓峰; 李健生; 姬广斌

    2011-01-01

    本工作采用CVD法在阳极氧化TiO2纳米管阵列膜表面沉积一层非晶Si膜,通过退火后得到晶化了的Si膜/TiO2纳米管阵列的复合结构,并初步就其光催化还原CO2制备碳氢化合物的活性进行研究.拉曼光谱(Raman)、X射线衍射(XRD)、场发射扫描电镜(FE-SEM)、高分辨透射电子显微镜(TEM)等微结构表征结果表明所制备的TiO2纳米管阵列的厚度为270 nm左右,管直径约为70 nm,管壁厚度约为16 nm.覆盖的Si膜已晶化,其厚度约为300 nm.通过高效液相色谱(HPLC)及总有机碳(TOC)来检测光催化还原液相产物中的甲酸及总有机碳含量,发现负载Si膜后的TiO2纳米管阵列光催化性能有所提高,在装有400cut滤光片氙灯照射2h下TOC含量从21.2 mg·L-1增长到29.5 mg· L-1,表明Si与TiO2的复合可有效的提高光催化还原CO2的活性,这可能与该异质结结构可增加对光的吸收并且可降低光生空穴-电子对复合有关.光催化循环实验表明所制得的催化剂在循环5次后仍可保持91.6%的催化活性.%In the current study, the composite structure of Si(thin film)/TiO2(nanotube arrays) has been fabricated via annealing amorphous TiO2 (nanotube arrays, synthesized by anodizing titanium foil) on which was coated by Si film through chemical vapor deposition (CVD) method, and the photocatalytic reduction of C02 for hydrocarbon compounds (such like formic acid) conversion on as-prepared Si/TiC^ structure has been initially investigated as well .The structure of Si/TiO2 nanotube arrays was characterized by X-ray powder ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectra (Raman) and transmission electron microscopy (TEM). The length, diameter and wall thickness of as-prepared TiO2 nanotube arrays were measured at about 270 nm, 70 nm and 16 nm, respectively. The thickness of the crystallized Si film was tested at around 300 nm. The amount total organic carbon as well as formic acid produced in

  9. Connecting CO2. Feasibility study CO2 network Southwest Netherlands; Connecting CO2. Haalbaarheidsstudie CO2-netwerk Zuidwest-Nederland

    Energy Technology Data Exchange (ETDEWEB)

    Rutten, M.

    2009-06-10

    An overview is given of supply and demand of CO2 in the region Southwest Netherlands and the regions Antwerp and Gent in Belgium. Also attention is paid to possible connections between these regions [Dutch] Een inventarisatie wordt gegeven van vraag en aanbod van CO2 in de regio Zuidwest- Nederland en de regios Antwerpen en Gent in Belgie. Ook worden mogelijke koppelingen tussen de regios besproken.

  10. The reversibility of CO2 induced climate change

    Science.gov (United States)

    Wu, Peili; Ridley, Jeff; Pardaens, Anne; Levine, Richard; Lowe, Jason

    2015-08-01

    This paper investigates the reversibility of CO2 induced climate change and in particular the potential impacts of different rates of CO2 reduction using a coupled climate model. Atmospheric CO2 concentration is ramped up by 0.5 %/year from the preindustrial value to 4×CO2 and then ramped down from 2×CO2 to 4×CO2 with different rates. How the response of the climate system is affected by the peak atmospheric CO2 concentration and the rate of long term decline is vital information for those considering hypothetical geoengineering options to remove CO2. Major components of the climate system including global mean surface air temperature and precipitation, contribution of thermal expansion to global sea level rise, loss of the Arctic sea ice, weakening of the Atlantic meridional overturning circulation (AMOC) and the South Asia monsoon are analyzed. We have found no `tipping points' or thresholds beyond which CO2 induced climate change in these components become irreversible within this model under the specific scenarios. However, there are strong inertias and path-dependent hysteresis in the climate system linked through oceanic memory. Initially the strengthened global hydrological cycle accelerates further in response to a CO2 ramp-down before weakening. Thermal expansion of the oceans continues for many decades after CO2 concentration starts to decrease. A 0.5 %/year reduction from 4×CO2 could see a further 25 % sea level rise. The weakening of the AMOC is reversible, but the build-up of highly saline subtropical waters during global warming drives an overshoot of the AMOC after the CO2 ramp-down and extends the warming of the northern high latitudes by many decades. The South Asia monsoon strengthens in response to a CO2 ramp-up marked by an increase in summer monsoon rainfall. This increase reverses rapidly following a CO2 ramp-down, displaying an undershoot in monsoon rainfall for rapid CO2 reductions.

  11. Synthesis and Design of a Sustainable CO2 Utilization Network

    DEFF Research Database (Denmark)

    Frauzem, Rebecca; Gani, Rafiqul

    In response to increasing regulations and concern about the impact of greenhouse gases on the environment, carbon dioxide (CO2) emissions are targeted for reduction. One method is the conversion of CO2 to useful compounds via chemical reactions. However, conversion is still in its infancy...... a superstructure-based approach a network of utilization alternatives is created linking CO2 and other raw materials with various products using processing blocks. This will then be optimized and verified for sustainability. Detailed design has also been performed for a case study on the methanol synthesis...... processing block. CO2 conversion processes show promise as an additional method for the sustainable reduction of CO2 emissions....

  12. Evaluation of the CO2 Poisoning Effect on a Highly Active Cathode SrSc(0.175)Nb(0.025)Co(0.8)O(3-δ) in the Oxygen Reduction Reaction.

    Science.gov (United States)

    Zhang, Yuan; Yang, Guangming; Chen, Gao; Ran, Ran; Zhou, Wei; Shao, Zongping

    2016-02-10

    A solid oxide fuel cell (SOFC) is a highly efficient device for converting chemical energy to electrical energy. In addition to the efforts to reduce the operating temperature of SOFCs to below 600 °C, research studies of the basic mechanism of CO2 poisoning on cathode materials are envisioned to improve the operation of dual-chamber SOFCs using ambient air. In this work, we comparatively studied the CO2 poisoning effect on two highly active perovskites SrSc(0.175)Nb(0.025)Co(0.8)O(3-δ) (SSNC) and Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) (BSCF), using complementary characterization techniques, e.g., powder X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), CO2-temperature-programmed desorption (CO2-TPD), and electrochemical impedance spectroscopy (EIS). The SSNC cathode shows better tolerance to CO2 as compared with BSCF, which is attributed to the absence of Ba, higher average metal-oxygen bond energy (ABE) of SSNC, and the higher acidity of Nb(5+) cations, whereas the oxygen vacancy concentration plays a less important role.

  13. Sourcing hydrocarbons in CO2-rich in hydrothermal systems

    OpenAIRE

    Fiebig, J; F. Tassi; D'Alessandro, W.; A. B. Woodland

    2009-01-01

    Methane (CH4) emanating from a continental volcanichydrothermal system in Nisyros, Greece, is processed through the abiogenic reduction of mantle- and marine limestonederived CO2 [1]. Evidence for the occurrence of abiogenic hydrothermal reduction of CO2 is from the chemical and carbon isotopic equilibrium patterns. We have further characterized this abiogenic methane (C1) source for the concentrations of ethane (C2) and propane (C3), as well as for the hydrogen isotop...

  14. First-Principles Study of Photochemical Activation of CO2 by Ti-based Oxides

    Science.gov (United States)

    He, Haiying; Zapol, Peter; Curtiss, Larry

    2013-03-01

    The photochemical conversion of CO2 and H2O into energy-bearing hydrocarbon fuels provides an attractive way of mitigating the green-house gas CO2 and utilizing solar energy as a sustainable energy source. However, due to the high reduction potential and chemical inertness of CO2 molecules, the conversion rate of CO2 is impractically low. The activation of CO2 is critical in facilitating further reactions. By carrying out first-principles calculations of reaction pathways from CO2 to CO2-anions on Ti-based oxides including zeolites in the presence of photoexcited electrons, we have studied the initial step of CO2 activation via 1e transfer. It is shown that the CO2 reactivity of these surfaces strongly depends on the crystal structure, surface orientation, and presence of defects. This opens a new dimension in surface structure modification to enhance the CO2 adsorption and reduction on semiconductor surfaces.

  15. Preliminary study of a potential CO2 reservoir area in Hungary

    Science.gov (United States)

    Sendula, Eszter; Király, Csilla; Szabó, Zsuzsanna; Falus, György; Szabó, Csaba; Kovács, István; Füri, Judit; Kónya, Péter; Páles, Mariann; Forray, Viktória

    2014-05-01

    Since the first international agreement in 1997 (the Kyoto Protocol) the reduction of greenhouse gas emission has a key role in the European Union's energy and climate change policy. Following the Directive 2009/31/EC we are experiencing a significant change in the Hungarian national activity. Since the harmonization procedure, which was completed in May 2012, the national regulation obligates the competent authority to collect and regularly update all geological complexes that are potential for CO2 geological storage. In Hungary the most abundant potential storage formations are mostly saline aquifers of the Great Hungarian Plain (SE-Hungary), with sandstone reservoir and clayey caprock. The Neogene basin of the Great Hungarian Plain was subsided and then filled by a prograding delta system from NW and NE during the Late Miocene, mostly in the Pannonian time. The most potential storage rock was formed as a fine-grained sandy turbidite interlayered by thin argillaceous beds in the deepest part of the basin. It has relatively high porosity, depth and more than 1000 m thickness. Providing a regional coverage for the sandy turbidite, a 400-500 m thick argillaceous succession was formed in the slope environment. The composition, thickness and low permeability is expected to make it a suitable, leakage-safe caprock of the storage system. This succession is underlain by argillaceous rocks that were formed in the basin, far from sediment input and overlain by interfingering siltstone, sandstone and claystone succession formed in delta and shoreline environments and in the alluvial plain. Core samples have been collected from the potential reservoir rock and its cap rock in the Great Hungarian Plain's succession. The water compositions of the studied depth were known from well-log database. Using the information, acquired from these archive documents, we have constructed input data for geochemical modeling in order to to study the effect of pCO2 injection in the potential

  16. Water-in-Supercritical CO2 Microemulsion Stabilized by a Metal Complex.

    Science.gov (United States)

    Luo, Tian; Zhang, Jianling; Tan, Xiuniang; Liu, Chengcheng; Wu, Tianbin; Li, Wei; Sang, Xinxin; Han, Buxing; Li, Zhihong; Mo, Guang; Xing, Xueqing; Wu, Zhonghua

    2016-10-17

    Herein we propose for the first time the utilization of a metal complex for forming water-in-supercritical CO2 (scCO2 ) microemulsions. The water solubility in the metal-complex-stabilized microemulsion is significantly improved compared with the conventional water-in-scCO2 microemulsions stabilized by hydrocarbons. Such a microemulsion provides a promising route for the in situ CO2 reduction catalyzed by a metal complex at the water/scCO2 interface.

  17. In-situ synthesis of CoPc /TiO2 photo-catalyst and study of photo-catalysis reduction of CO2%原位合成CoPc/TiO2 光催化剂及其光催化还原CO2的研究

    Institute of Scientific and Technical Information of China (English)

    谢明明; 赵志换; 王志忠

    2007-01-01

    采用原位化学合成的新方法,在TiO2凝胶基质合成过程中以邻苯二腈为原料,通过其四聚反应将钴酞菁(CoPc)在TiO2表面原位合成,得到均匀掺杂的CoPc/TiO2光催化剂.将其用于可见光下还原CO2反应,以CO2还原效率为考察指标,用正交实验对此光催化剂的制备条件进行了优化,得出催化剂的最佳制备条件是:CoPc的负载量为TiO2的3%,焙烧温度为200 ℃,pH=1,搅拌时间为12 h.用此CoPc/TiO2光催化剂在可见光照射下,水溶液中即可光还原CO2为甲醇、甲醛、甲酸等产物,在光照反应10 h后总产量最高可达2 903.83 μmol/g催化剂.另外,采用紫外可见漫反射光谱证实了CoPc在TiO2表面的成功掺杂.

  18. Influence of Reaction Medium on CO2 Photocatalytic Reduction Yields Over Zns-MMT / Vliv Reakčního Prostření Na Výtěžky Fotokatalytické Redukce CO2 V Přítomnosti Zns-MMT

    Directory of Open Access Journals (Sweden)

    Reli Martin

    2012-10-01

    Full Text Available Redukce CO2 pomocí fotokatalyzátorů je jedna z nejslibnějších metod, jelikož CO2 může být redukován na užitečné sloučeniny ozařováním UV zářením při pokojové teplotě a tlaku. Tato práce byla zaměřena na posouzení vlivu reakčních prostředí na výtěžky fotokatalytické redukce CO2 v přítomnosti nanočástic ZnS nanesených na montmorillonit (ZnS-MMT. Byla testována čtyři různá reakční prostředí, NaOH, NaOH+Na2SO3 (1:1, NH4OH, NH4OH+Na2SO3 (1:1. Výtěžky v obou fázích, plynné (CH4 a CO i kapalné (CH3OH, byly vyšší v čistém hydroxidu sodném než v hydroxidu amonném. Přídavek Na2SO3 zvýšil výtěžky methanolu a to díky zamezení oxidace vznikajícího methanolu zpět na oxid uhličitý. Výtěžky plynné fáze se však po přídavku Na2SO3 snížily. Nejlepším z testovaných reakčních prostředí pro fotokatalytickou redukci CO2 byl roztok hydroxidu sodného.

  19. ACCURACY OF CO2 SENSORS

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Integrated Geophysical Monitoring Program to Study Flood Performance and Incidental CO2 Storage Associated with a CO2 EOR Project in the Bell Creek Oil Field

    Science.gov (United States)

    Burnison, S. A.; Ditty, P.; Gorecki, C. D.; Hamling, J. A.; Steadman, E. N.; Harju, J. A.

    2013-12-01

    The Plains CO2 Reduction (PCOR) Partnership, led by the Energy & Environmental Research Center, is working with Denbury Onshore LLC to determine the effect of a large-scale injection of carbon dioxide (CO2) into a deep clastic reservoir for the purpose of simultaneous CO2 enhanced oil recovery (EOR) and to study incidental CO2 storage at the Bell Creek oil field located in southeastern Montana. This project will reduce CO2 emissions by more than 1 million tons a year while simultaneously recovering an anticipated 30 million barrels of incremental oil. The Bell Creek project provides a unique opportunity to use and evaluate a comprehensive suite of technologies for monitoring, verification, and accounting (MVA) of CO2 on a large-scale. The plan incorporates multiple geophysical technologies in the presence of complementary and sometimes overlapping data to create a comprehensive data set that will facilitate evaluation and comparison. The MVA plan has been divided into shallow and deep subsurface monitoring. The deep subsurface monitoring plan includes 4-D surface seismic, time-lapse 3-D vertical seismic profile (VSP) surveys incorporating a permanent borehole array, and baseline and subsequent carbon-oxygen logging and other well-based measurements. The goal is to track the movement of CO2 in the reservoir, evaluate the recovery/storage efficiency of the CO2 EOR program, identify fluid migration pathways, and determine the ultimate fate of injected CO2. CO2 injection at Bell Creek began in late May 2013. Prior to injection, a monitoring and characterization well near the field center was drilled and outfitted with a distributed temperature-monitoring system and three down-hole pressure gauges to provide continuous real-time data of the reservoir and overlying strata. The monitoring well allows on-demand access for time-lapse well-based measurements and borehole seismic instrumentation. A 50-level permanent borehole array of 3-component geophones was installed in a

  1. Assessing the effectiveness of winter cover crop on nitrate reduction in two-paired sub-basins on the Coastal Plain of the Chesapeake Bay Watershed

    Science.gov (United States)

    Lee, S.; Yeo, I. Y.; Sadeghi, A. M.; Mccarty, G.; Hively, W. D.; Lang, M. W.

    2014-12-01

    Best management practices (BMPs) have been widely adopted to improve water quality throughout the Chesapeake Bay Watershed (CBW). Winter cover crops (WCC) use has been highlighted for the reduction of nitrate leaching over the fallow season. Although various WCC practices are currently conducted in local croplands, the water quality improvement benefits of WCC have not been studied thoroughly at the watershed scale. The objective of this study is to assess the long-term impacts of WCC on reducing nitrate loadings using a processed-based watershed model, Soil and Water Assessment Tool (SWAT). Remote sensing based estimates of WCC biomass will be used to calibrate plant growth processes of SWAT and its nutrient cycling. The study will be undertaken in two-paired agricultural watersheds in the Coastal Plain of CBW. Multiple WCC practice scenarios will be prepared to investigate how nitrate loading varies with crop species, planting dates, and implementation areas. The performance of WCC on two-paired watersheds will be compared in order to understand the effects of different watershed characteristics on nitrate uptake by crops. The results will demonstrate the nitrate reduction efficiency of different WCC practices and identify the targeting area for WCC implementation at the watershed scale. This study will not only integrate remote sensing data into the physically based model but also extend our understandings of WCC functions. This will provide key information for effective conservation decision making. Key words: Water quality, Chesapeake Bay Watershed, Winter Cover Crop, Soil and Water Assessment Tool (SWAT)

  2. Ultrasound-assisted CO2 flooding to improve oil recovery.

    Science.gov (United States)

    Hamidi, Hossein; Sharifi Haddad, Amin; Mohammadian, Erfan; Rafati, Roozbeh; Azdarpour, Amin; Ghahri, Panteha; Ombewa, Peter; Neuert, Tobias; Zink, Aaron

    2017-03-01

    CO2 flooding process as a common enhanced oil recovery method may suffer from interface instability due to fingering and gravity override, therefore, in this study a method to improve the performance of CO2 flooding through an integrated ultraosund-CO2 flooding process is presented. Ultrasonic waves can deliver energy from a generator to oil and affect its properties such as internal energy and viscosity. Thus, a series of CO2 flooding experiments in the presence of ultrasonic waves were performed for controlled and uncontrolled temperature conditions. Results indicate that oil recovery was improved by using ultrasound-assisted CO2 flooding compared to conventional CO2 flooding. However, the changes were more pronounced for uncontrolled temperature conditions of ultrasound-assisted CO2 flooding. It was found that ultrasonic waves create a more stable interface between displacing and displaced fluids that could be due to the reductions in viscosity, capillary pressure and interfacial tension. In addition, higher CO2 injection rates, increases the recovery factor in all the experiments which highlights the importance of injection rate as another factor on reduction of the fingering effects and improvement of the sweep efficiency.

  3. AMESCO General Study Environmental Impacts CO2-storage. Public summary

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-15

    The AMESCO study aims to supply environmental background information on CO2-storage in the Netherlands for the broad group of initiators and other stakeholders. By bringing together the information from the scientific world, companies and authorities and by analysing relevant policies it is intended to eludicate: which are the possible environmental effects of CO2-injection and storage; which are the possibilities for risk reduction or mitigation; which existing legislation is of relevance for CO2-storage in the deep surface; where are the gaps in knowledge and legislation with regard to CO2-storage. The report produced during the AMESCO study should be seen as a broad answer to the four questions mentioned above. In specific projects the report can be used as a background document during permitting procedures. This background information has to be supplemented with location specific information. The report can also be used as input for an environmental impact assessment (EIA). For practical reasons the AMESCO study was performed with the following scope limitations: (1) Focus on potential impacts and risks resulting from the storage of CO2; (2) Only consider CO2-storage in gas reservoirs; (3) Only consider onshore projects; (4) Only consider permanent storage; (5) Consider alternative options for CO2-storage in gas reservoirs; but not other forms of CO2-emission reduction. The scope is limited to depleted gas fields, from which the economically recoverable resources have already been taken.

  4. Electrocatalytic recycling of CO2 and small organic molecules.

    Science.gov (United States)

    Lee, Jaeyoung; Kwon, Youngkook; Machunda, Revocatus L; Lee, Hye Jin

    2009-10-05

    As global warming directly affects the ecosystems and humankind in the 21st century, attention and efforts are continuously being made to reduce the emission of greenhouse gases, especially carbon dioxide (CO2). In addition, there have been numerous efforts to electrochemically convert CO2 gas to small organic molecules (SOMs) and vice versa. Herein, we highlight recent advances made in the electrocatalytic recycling of CO2 and SOMs including (i) the overall trend of research activities made in this area, (ii) the relations between reduction conditions and products in the aqueous phase, (iii) the challenges in the use of gas diffusion electrodes for the continuous gas phase CO2 reduction, as well as (iv) the development of state of the art hybrid techniques for industrial applications. Perspectives geared to fully exploit the potential of zero-gap cells for CO2 reduction in the gaseous phase and the high applicability on a large scale are also presented. We envision that the hybrid system for CO2 reduction supported by sustainable solar, wind, and geothermal energies and waste heat will provide a long term reduction of greenhouse gas emissions and will allow for continued use of the abundant fossil fuels by industries and/or power plants but with zero emissions.

  5. The CO2nnect activities

    Science.gov (United States)

    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

  6. Achieving Negative CO2 Emissions by Protecting Ocean Chemistry

    Science.gov (United States)

    Cannara, A.

    2016-12-01

    Industrial Age CO2 added 1.8 trillion tons to the atmosphere. About ¼ has dissolved in seas. The rest still dissolves, bolstered by present emissions of >30 gigatons/year. Airborne & oceanic CO2 have induced sea warming & ocean acidification*. This paper suggests a way to induce a negative CO2-emissions environment for climate & oceans - preserve the planet`s dominant CO2-sequestration system ( 1 gigaton/year via calcifying sea life**) by promptly protecting ocean chemistry via expansion of clean power for both lime production & replacement of CO2-emitting sources. Provide natural alkali (CaO, MgO…) to oceans to maintain average pH above 8.0, as indicated by marine biologists. That alkali (lime) is available from past calcifying life's limestone deposits, so can be returned safely to seas once its CO2 is removed & permanently sequestered (Carbfix, BSCP, etc.***). Limestone is a dense source of CO2 - efficient processing per mole sequestered. Distribution of enough lime is possible via cargo-ship transits - 10,000 tons lime/transit, 1 million transits/year. New Panamax ships carry 120,000 tons. Just 10,000/transit allows gradual reduction of present & past CO2 emissions effects, if coupled with combustion-power reductions. CO2 separation from limestone, as in cement plants, consumes 400kWHrs of thermal energy per ton of output lime (or CO2). To combat yearly CO2 dissolution in seas, we must produce & distribute about 10gigatons of lime/year. Only nuclear power produces the clean energy (thousands of terawatt hours) to meet this need - 1000 dedicated 1GWe reactors, processing 12 cubic miles of limestone/year & sequestering CO2 into a similar mass of basalt. Basalt is common in the world. Researchers*** report it provides good, mineralized CO2 sequestration. The numbers above allow gradual CO2 reduction in air and seas, if we return to President Kennedy's energy path: http://tinyurl.com/6xgpkfa We're on an environmental precipice due to failure to eliminate

  7. Reducing cement's CO2 footprint

    Science.gov (United States)

    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.

  8. Monitoring subsurface CO2 storage

    NARCIS (Netherlands)

    Winthaegen, P.; Arts, R.; Schroot, B.M.

    2005-01-01

    An overview is given of various currently applied monitoring techniques for CO2 storage. Techniques are subdivided in correspondence to their applicability for monitoring three distinct realms. These are: - the atmosphere and the near-surface; - the overburden (including faults and wells); - the

  9. Diamino protic ionic liquids for CO2 capture.

    Science.gov (United States)

    Vijayraghavan, R; Pas, Steven J; Izgorodina, Ekaterina I; MacFarlane, Douglas R

    2013-12-14

    A series of multifunctional protic ionic liquids (PILs), some of which are based on a combination of primary and tertiary amines in the same moiety coupled with a carboxylic acid, have been synthesised and employed for CO2 capture, yielding absorption capacities comparable to standard absorbents. In contrast to traditional amine absorbers, CO2 was found to desorb at lower temperatures and hence could result in a significant reduction in both the energy required to strip the absorber of CO2 and the thermally activated degradation mechanisms, which in traditional absorbers result in the loss of absorber and the production of toxic compounds. The lower basicity of the amine sites resultant from PIL formation decreases the binding energy of the CO2 to the absorber. The weaker basicity is also evidenced by lower pH of the PIL CO2 absorbers, which reduces common corrosion problems associated with traditional amine absorbers.

  10. Excitation of CO2/+/ by electron impact on CO2

    Science.gov (United States)

    Mentall, J. E.; Coplan, M. A.; Kushlis, R. J.

    1973-01-01

    Consideration of a discrepancy concerning the correct value of the cross section for excitation of the CO2(+) B state by electron impact on CO2. It is suggested that the reason for the disparate results obtained by various authors for the B state can be traced to a calibration error due to scattered light. In particular, the tungsten filament lamps used in the experiments cited have very low intensity at wavelengths below 3000 A where the B state emissions occur, so that even a small amount of scattered light in the spectrometer will produce a large error in the measured cross section. In a remeasurement of the cross section for excitation of the B state at an energy of 150 eV it was found that at 2900 A the scattered light signal, if uncorrected for, would introduce an error of about 50%.

  11. Research on CO2 Quality Pipeline Transportation Based on Yanchang Oilfield CCUS

    Directory of Open Access Journals (Sweden)

    Yang Yongchao

    2017-01-01

    Full Text Available CO2 capture,utilization and storage (CCUS is now recognized as an important technology in the global scope of CO2 emission reduction, pipeline transportation is the main center to connect the capture point and the use storage point, the first issue to CO2 pipeline transportation is to solve CO2 source quality research. Yanchang Oilfield has the advantages of CCUS, its coal chemical capture of CO2 contains different impurities. In the CO2 pipeline transportation, the impurity content in CO2 is based on its end use and the actual situation of pipeline. The impurities will affect the efficiency of CO2-EOR, the choice of CO2 state equation, the changes of CO2 phase diagram and the capacity of pipeline transportation.

  12. A Quantitative Investigation of CO2 Sequestration by Mineral Carbonation

    CERN Document Server

    Mohammad, Muneer

    2015-01-01

    Anthropogenic activities have led to a substantial increase in carbon dioxide (CO2), a greenhouse gas (GHG), contributing to heightened concerns of global warming. In the last decade alone CO2 emissions increased by 2.0 ppm/yr. globally. In the year 2009, United States and China contributed up to 43.4% of global CO2 emissions. CO2 capture and sequestration have been recognized as promising solutions to mitigate CO2 emissions from fossil fuel based power plants. Typical techniques for carbon capture include post-combustion capture, pre-combustion capture and oxy-combustion capture, which are under active research globally. Mineral carbonation has been investigated as a suitable technique for long term storage of CO2. Sequestration is a highly energy intensive process and the additional energy is typically supplied by the power plant itself. This leads to a reduction in net amount of CO2 captured because of extra CO2 emitted. This paper presents a quantitative analysis of the energy consumption during sequestra...

  13. Synthesis of Ag/N-TiO2/SBA-15 Photocatalysts and Photocatalytic Reduction of CO2 under Visible Light irradiation%Ag/N-TiO2/SBA-15光催化剂的制备及其可见光催化还原CO2

    Institute of Scientific and Technical Information of China (English)

    高梦语; 姜东; 孙德魁; 侯博; 李德宝

    2014-01-01

    以钛酸四正丁酯(TB),羧基改性的SBA-15 (COOH/SBA-15),尿素和AgNO3为原料,利用溶剂热及焙烧处理制得Ag/N-TiO2/SBA-15催化剂.采用X射线衍射(XRD),低温N2吸脱附,X射线光电子能谱(XPS),紫外可见漫反射光谱(UV-vis DRS),荧光(PL)光谱,电感耦合等离子体原子发射光谱(ICP)和元素分析(EA)等表征.结果显示:Ag/N-TiO2/SBA-15样品具有介孔结构,TiO2以单一的锐钛矿晶型均匀的分散在载体表面,Ag以单质形态沉积在TiO2表面,N则掺入到TiO2晶格中,并以取代N(O-Ti-N)和间隙N(Ti-O-N)两种方式共存.Ag/N-TiO2/SBA-15催化剂中单质Ag既可以捕获光生电子提高量子效率,又促进了TiO2对可见光的吸收.N掺杂拓宽了TiO2吸收光谱的吸收范围,并且适量的N掺杂有助于光生电荷的分离,提高了光催化效率.以光催化还原CO2为探针反应,考察了催化剂在可见光下的催化活性.结果表明:Ag/N-TiO2/SBA-15系列催化剂均表现出了可见光催化还原CO2性能,发现当Ag的质量分数为2%,N与Ti的物质的量比为3时,催化剂光催化活性最佳,产物甲醇产量高达45.7 μmol·g-1·h-1.

  14. Fang CO2 med Aminosyrer

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai

    2010-01-01

    Med såkaldte “carbon capture-teknikker” er det muligt at rense røgen fra kulfyrede kraftværker, således at den er næsten helt fri for drivhusgassen CO2. Kunsten er at gøre processen tilstrækkeligt billig. Et lovende fangstredskab i denne proces er aminosyrer.......Med såkaldte “carbon capture-teknikker” er det muligt at rense røgen fra kulfyrede kraftværker, således at den er næsten helt fri for drivhusgassen CO2. Kunsten er at gøre processen tilstrækkeligt billig. Et lovende fangstredskab i denne proces er aminosyrer....

  15. Effect of Calcination Temperature and Calcination Time on the Kaolinite/TIO2 Composite for Photocatalytic Reduction of Co2/ Vliv Kalcinační Teploty A Doby Kalcinace Na Kompozit Kaolinit/TIO2 Pro Fotokatalytickou Redukci Co2

    Directory of Open Access Journals (Sweden)

    Reli Martin

    2012-12-01

    Full Text Available Kompozit kaolinit/TiO2 (60 hm% TiO2 byl připraven termální hydrolýzou suspenze surového kaolinu v síranu titanylu a kalcinován při různých teplotách (600, 650 a 700°C a po různou dobu (1, 2 a 3 h. Získaný vzorek byl charakterizován pomocí XRPD, N2 fyzikální adsorpcí a SEM, a testován na fotokatalytickou redukci CO2. Rozdíl kalcinačních podmínek neovlivnil složení fáze TiO2, pouze se mírně pozměnila specifická povrchová plocha a výrazně byla ovlivněna velikost krystalitu kompozitu kaolinit/TiO2. Vyšší teplota a delší doba kalcinace vedly k vyšší krystalitě prášku. Fotokatalytické výsledky ukázaly, že velikost krystality určuje účinnost fotokatalyzítoru kaolinit/TiO2

  16. Techno-Economic Assessment of a Biomass-Based Cogeneration Plant with CO2 Capture and Storage

    OpenAIRE

    Uddin, N

    2004-01-01

    Reduction of CO2 emissions from energy systems could be achieved through: CO2 capture and storage, energy savings, fuel switching among fossil fuels, increased use of renewable energy sources, and nuclear power. In addition, atmospheric CO2 reduction could also be achieved through increasing the carbon stock in soils and standing biomass. The CO2 capture and storage option for mitigating CO2 emissions from biomass-based cogeneration plants, considering critical aspects such future development...

  17. CO2 Exsolution from CO2 Saturated Water: Core-Scale Experiments and Focus on Impacts of Pressure Variations.

    Science.gov (United States)

    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.

  18. 一种高效节能降耗的碳碱法制造硼砂新工艺%A new process of producing borax by CO2 -soda method with high efficiency, energy saving, and consumption reduction

    Institute of Scientific and Technical Information of China (English)

    胡德生; 逯双佳; 仲剑初

    2011-01-01

    通过对现行的碳碱法制硼砂的工艺过程进行分析,提出碳解过程可分为反应初期、主反应期和反应末期3个阶段.反应初期和末期吸收速率大于反应速率;主反应期开始吸收速率大于反应速率,后期二者相当.针对反应过程的特点,提出了改进碳解反应的核心是提高碳解的二氧化碳压力和适当提高温度,并对现行工艺进行了改进.改进后的工艺技术指标为:硼矿碳解率90%、碳解时间9h、二氧化碳利用率大于96%、蒸汽消耗(以1 t硼砂计)1 292 kg.改进后的碳碱法工艺与原工艺比,反应时间缩短了1/2,能耗显著减少,二氧化碳减排效果明显,有助于提高环境质量.%According to the analysis on the production of borax by CO2 - soda process, the reaction in this process can be divided into three parts: initial, main, and final reaction stages. The adsorption rate is faster than the reaction rates in the initial-and final-reaction stages,while the adsorption rate is first faster than reaction rate and then gradually become the same in the main reaction stage. Based on these characters of this process,the measurements for raising CO2 partial pressure and reaction temperature were made to improve this process. The suitable process conditions were as follows: the carbonate decomposing rate for B2O3 in ascharite was 90% , reaction time was 9 h,CO2 recovery rate was more than 96% and steam consumption was 1 292 kg (1 t borax). Compared with old process, the reaction time of new process has been shorted to half one of old process and energy consumption has also been reduced significantly. The new process can reduce CO2 emission and improve environmental quality.

  19. Reactivity of CO2 Activated on Transition Metals and Sulfur Ligands.

    Science.gov (United States)

    Kobayashi, Katsuaki; Tanaka, Koji

    2015-06-01

    Dicationic dicarbonyl [Ru(bpy)2(CO)2](2+) (bpy = 2,2'- bipyridyl) exists as equilibrium mixtures with [Ru(bpy)2(CO)(COOH)](+) and [Ru(bpy)2(CO)(CO2)](0) depending on the pH in H2O. Those three complexes work as the precursors to CO, HCOOH production, and CO2 carrier, respectively, in electro- and photochemical CO2 reduction in aqueous solutions. However, [Ru(bpy)2(CO)2](2+) loses the catalytic activity toward CO2 reduction under aprotic conditions because [Ru(bpy)2(CO)2](2+) is not regenerated from [Ru(bpy)2(CO)(CO2)](0) in the absence of proton sources. Analogous monocarbonylruthenium complexes such as [Ru(tpy)(bpy)(CO)](2+) and [Ru(bpy)2(qu)(CO)](2+) catalyze CO2 reduction in the absence and presence of proton sources. Both complexes are reproduced through oxide transfer from the corresponding Ru-CO2 to CO2 in CO2 reduction and produce the same amount of CO and CO3(2-) in the absence of proton donors. The reduction of CO2 catalyzed by polypyridylrhenium complexes in the presence of proton sources takes place via essentially the similar mechanism as that in the case of ruthenium complexes. On the other hand, CO evolution in CO2 reduction under aprotic conditions is ascribed to the dissociation of CO from a dimeric Re-C(O)OC(O)O-Re scaffold. Visible-light irradiation to a catalytic system composed of [Ru(bpy)2(CO)2](2+)/[Ru(bpy)3](2+)/Me2NH2(+)/Me2NH as the catalyst, photosensitizer, proton donor, and nucleophile in addition to the electron donor, respectively, in CO2-saturated CH3CN selectively produces N,N-dimethylformamide without concomitant CO and HCOOH formation. Structurally robust μ3-S of reduced metal-sulfur clusters provides a suitable site for reductive activation of CO2 with retention of the framework. Indeed, CO2 activated on μ3-S of [Fe6Mo2S8(SEt)3](5-) is fixed at the carbonyl carbon of thioesters trapped on a neighboring iron of the cluster, and α-keto acids are produced catalytically. Furthermore, two-electron reduction of [(CpMen)3M3S3](2+) (n

  20. European Community Can Reduce CO2 Emissions by Sixty Percent : A Feasibility Study

    NARCIS (Netherlands)

    Mot, E.; Bartelds, H.; Esser, P.M.; Huurdeman, A.J.M.; Laak, P.J.A. van de; Michon, S.G.L.; Nielen, R.J.; Baar, H.J.W. de

    1993-01-01

    Carbon dioxide (CO2) emissions in the European Community (EC) can be reduced by roughly 60 percent. A great many measures need to be taken to reach this reduction, with a total annual cost of ECU 55 milliard. Fossil fuel use is the main cause of CO2 emissions into the atmosphere; CO2 emissions are t

  1. Efficient CO2 capture and photoreduction by amine-functionalized TiO2.

    Science.gov (United States)

    Liao, Yusen; Cao, Shao-Wen; Yuan, Yupeng; Gu, Quan; Zhang, Zhenyi; Xue, Can

    2014-08-11

    Amine-functionalization of TiO2 nanoparticles, through a solvothermal approach, substantially increases the affinity of CO2 on TiO2 surfaces through chemisorption. This chemisorption allows for more effective activation of CO2 and charge transfer from excited TiO2 , and significantly enhances the photocatalytic rate of CO2 reduction into methane and CO.

  2. Carbon Emission Reduction Based on the Utilization of Microalgae and its Fixation of CO2%基于微藻资源化利用的碳减排技术

    Institute of Scientific and Technical Information of China (English)

    郑赞永; 曾旭; 震林

    2014-01-01

    Microalgae is one of the promising biodiesel resources, which possesses some merits, for example, higher photosynthesis rates, zero net carbon, shorter growth cycle, easy to feed, high content of oil, etc. Microalgae biodiesel has attracted a lot of attention based on the couple of utilization of microalgae and its fixation of CO 2. The literature of the filtration, cultivation and the reactor development of the microalgae technology, and the microalgae utilization technology were reviewed. Finally, perspectives of the microalgae biodiesel technique were also discussed.%微藻具有光合效率高、零净碳值、生长周期短、易培养、油含量高等优点,是一种极具前景的生物柴油原料。将微藻资源化利用与碳减排耦合的微藻生物柴油技术研究已受到政府和企业的广泛关注。综述了微藻高效固定CO2技术中微藻种类的筛选、培育、生长反应器及其系统的开发,微藻资源化利用的技术种类,展望了基于微藻资源化利用的碳减排技术的发展前景。

  3. Comparison of CO2 emission between COREX and blast furnace iron-making system.

    Science.gov (United States)

    Hu, Changqing; Han, Xiaowei; Li, Zhihong; Zhang, Chunxia

    2009-01-01

    Steel works faced increasing demand to minimize the emission of GHGs. The CO2 emissions of COREX and blast furnace iron-making system were compared. It is point out that COREX contribute little to CO2 emission reduction. Comparing to conventional blast furnace iron-making system, direct CO2 emissions of COREX is higher. Considering the credits of export gases for power generation, the total CO2 emission of COREX have advantages only when the COREX is joined with high-efficiency generating units which efficiency is greater than 45% and CO2 emission factor of the grid is higher than 0.9 kgCO2/kWh.

  4. RODZAJE METOD SEKWESTRACJI CO2

    Directory of Open Access Journals (Sweden)

    Zofia LUBAŃSKA

    Full Text Available Z pojęciem ochrony środowiska wiąże się bardzo szeroko w ostatnim czasie omawiane zagadnienie dotyczące ograniczenia emisji CO2. Konsekwencją globalnych zmian klimatu wywołanego przez ludzi jest wzrost stężenia atmosferycznego gazów cieplarnianych, które powodują nasilający się efekt cieplarniany. Wzrasta na świecie liczba ludności, a co za tym idzie wzrasta konsumpcja na jednego mieszkańca, szczególnie w krajach szeroko rozwiniętych gospodarczo. Protokół z Kioto ściśle określa działania jakie należy podjąć w celu zmniejszenia stężenia dwutlenku węgla w atmosferze. Pomimo maksymalnej optymalizacji procesu spalania paliw kopalnianych wykorzystywanych do produkcji energii, zastosowania odnawialnych źródeł energii zmiana klimatu jest nieunikniona i konsekwentnie będzie postępować przez kolejne dekady. Prognozuje się, że duże znaczenie odegra nowoczesna technologia, która ma za zadanie wychwycenie CO2 a następnie składowanie go w odpowiednio wybranych formacjach geologicznych (CCS- Carbon Capture and Storage. Eksperci są zgodni, że ta technologia w niedalekiej przyszłości stanie się rozwiązaniem pozwalającym ograniczyć ogromną ilość emisji CO2 pochodzącą z procesów wytwarzania energii z paliw kopalnych. Z analiz Raportu IPCC wynika, iż technologia CSS może się przyczynić do ok. 20% redukcji emisji dwutlenku węgla przewidzianej do 2050 roku [3]. Zastosowanie jej napotyka na wiele barier, nie tylko technologicznych i ekonomicznych, ale także społecznych. Inną metodą dającą ujemne źródło emisji CO2 jest możliwość wykorzystania obszarów leśnych o odpowiedniej strukturze drzewostanu. Środkiem do tego celu, oprócz ograniczenia zużycia emisjogennych paliw kopalnych (przy zachowaniu zasad zrównoważonego rozwoju może być intensyfikacja zalesień. Zwiększanie lesistości i prawidłowa gospodarka leśna należy do najbardziej efektywnych sposobów kompensowania

  5. Surface Condensation of CO2 onto Kaolinite

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. The Value of CO2-Geothermal Bulk Energy Storage to Reducing CO2 Emissions Compared to Conventional Bulk Energy Storage Technologies

    Science.gov (United States)

    Ogland-Hand, J.; Bielicki, J. M.; Buscheck, T. A.

    2016-12-01

    Sedimentary basin geothermal resources and CO2 that is captured from large point sources can be used for bulk energy storage (BES) in order to accommodate higher penetration and utilization of variable renewable energy resources. Excess energy is stored by pressurizing and injecting CO2 into deep, porous, and permeable aquifers that are ubiquitous throughout the United States. When electricity demand exceeds supply, some of the pressurized and geothermally-heated CO2 can be produced and used to generate electricity. This CO2-BES approach reduces CO2 emissions directly by storing CO2 and indirectly by using some of that CO2 to time-shift over-generation and displace CO2 emissions from fossil-fueled power plants that would have otherwise provided electricity. As such, CO2-BES may create more value to regional electricity systems than conventional pumped hydro energy storage (PHES) or compressed air energy storage (CAES) approaches that may only create value by time-shifting energy and indirectly reducing CO2 emissions. We developed and implemented a method to estimate the value that BES has to reducing CO2 emissions from regional electricity systems. The method minimizes the dispatch of electricity system components to meet exogenous demand subject to various CO2 prices, so that the value of CO2 emissions reductions can be estimated. We applied this method to estimate the performance and value of CO2-BES, PHES, and CAES within real data for electricity systems in California and Texas over the course of a full year to account for seasonal fluctuations in electricity demand and variable renewable resource availability. Our results suggest that the value of CO2-BES to reducing CO2 emissions may be as much as twice that of PHES or CAES and thus CO2-BES may be a more favorable approach to energy storage in regional electricity systems, especially those where the topography is not amenable to PHES or the subsurface is not amenable to CAES.

  7. Energy efficiency and CO2 emissions in Swedish manufacturing industries

    Energy Technology Data Exchange (ETDEWEB)

    Pardo Martinez, C.I. [Faculty of Environmental Engineering, University of La Salle, Bogota (Colombia); Silveira, S [Energy and Climate Studies, Department of Energy Technology, KTH, Stockholm (Sweden)

    2013-02-15

    This paper analyses the trends in energy consumption and CO2 emissions as a result of energy efficiency improvements in Swedish manufacturing industries between 1993 and 2008. Using data at the two-digit level, the performance of this sector is studied in terms of CO2 emissions, energy consumption, energy efficiency measured as energy intensity, value of production, fuel sources, energy prices and energy taxes. It was found that energy consumption, energy intensity and CO2 emission intensity, measured as production values, have decreased significantly in the Swedish manufacturing industries during the period studied. The results of the decomposition analysis show that output growth has not required higher energy consumption, leading to a reduction in both energy and CO2 emission intensities. The role of structural changes has been minor, and the trends of energy efficiency and CO2 emissions have been similar during the sample period. A stochastic frontier model was used to determine possible factors that may have influenced these trends. The results demonstrate that high energy prices, energy taxes, investments and electricity consumption have influenced the reduction of energy and CO2 emission intensities, indicating that Sweden has applied an adequate and effective energy policy. The study confirms that it is possible to achieve economic growth and sustainable development whilst also reducing the pressure on resources and energy consumption and promoting the shift towards a low-carbon economy.

  8. Costs of mitigating CO2 emissions from passenger aircraft

    Science.gov (United States)

    Schäfer, Andreas W.; Evans, Antony D.; Reynolds, Tom G.; Dray, Lynnette

    2016-04-01

    In response to strong growth in air transportation CO2 emissions, governments and industry began to explore and implement mitigation measures and targets in the early 2000s. However, in the absence of rigorous analyses assessing the costs for mitigating CO2 emissions, these policies could be economically wasteful. Here we identify the cost-effectiveness of CO2 emission reductions from narrow-body aircraft, the workhorse of passenger air transportation. We find that in the US, a combination of fuel burn reduction strategies could reduce the 2012 level of life cycle CO2 emissions per passenger kilometre by around 2% per year to mid-century. These intensity reductions would occur at zero marginal costs for oil prices between US$50-100 per barrel. Even larger reductions are possible, but could impose extra costs and require the adoption of biomass-based synthetic fuels. The extent to which these intensity reductions will translate into absolute emissions reductions will depend on fleet growth.

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

    Science.gov (United States)

    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

  10. Metal-Organic Frameworks for CO2 Chemical Transformations.

    Science.gov (United States)

    He, Hongming; Perman, Jason A; Zhu, Guangshan; Ma, Shengqian

    2016-12-01

    Carbon dioxide (CO2 ), as the primary greenhouse gas in the atmosphere, triggers a series of environmental and energy related problems in the world. Therefore, there is an urgent need to develop multiple methods to capture and convert CO2 into useful chemical products, which can significantly improve the environment and promote sustainable development. Over the past several decades, metal-organic frameworks (MOFs) have shown outstanding heterogeneous catalytic activity due in part to their high internal surface area and chemical functionalities. These properties and the ability to synthesize MOF platforms allow experiments to test structure-function relationships for transforming CO2 into useful chemicals. Herein, recent developments are highlighted for MOFs participating as catalysts for the chemical fixation and photochemical reduction of CO2 . Finally, opportunities and challenges facing MOF catalysts are discussed in this ongoing research area. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. A rapid transition from ice covered CO2-rich waters to a biologically mediated CO2 sink in the eastern Weddell Gyre

    Directory of Open Access Journals (Sweden)

    W. Geibert

    2008-03-01

    Full Text Available Circumpolar Deep Water (CDW, locally called Warm Deep Water (WDW, enters the Weddell Gyre in the southeast, roughly at 25° E to 30° E. In December~2002 and January 2003} we studied the effect of entrainment of WDW on the fugacity of carbon dioxide (fCO2 and dissolved inorganic carbon (DIC in Weddell Sea surface waters. Ultimately the fCO2 difference across the sea surface drives CO2 air-sea fluxes. Deep CTD sections and surface transects of fCO2 were made along the Prime Meridian, a northwest-southeast section, and along 17° E to 23° E during cruise ANT XX/2 on FS Polarstern. Upward movement and entrainment of WDW into the winter mixed layer had significantly increased DIC and fCO2 below the sea ice along 0° W and 17° E to 23° E, notably in the southern Weddell Gyre. Nonetheless, the ice cover largely prevented outgassing of CO2 to the atmosphere. During and upon melting of the ice, biological activity rapidly reduced surface water fCO2 by up to 100 μatm, thus creating a sink for atmospheric CO2. Despite the tendency of the surfacing WDW to cause CO2 supersaturation, the Weddell Gyre may well be a CO2 sink on an annual basis due to this effective mechanism involving ice cover and ensuing biological fCO2 reduction. Dissolution of calcium carbonate (CaCO3 in melting sea ice may also play a role in this rapid reduction of surface water fCO2. The CO2 source tendency deriving from the upward movement of "pre-industrial" CDW is declining, as atmospheric CO2 levels continue to increase, and thus the CO2 sink of the Weddell Gyre will continue to increase as well (provided the upward movement of WDW does not change significantly.

  12. Translating crustacean biological responses from CO2 ...

    Science.gov (United States)

    Many studies of animal responses to ocean acidification focus on uniformly conditioned age cohorts that lack complexities typically found in wild populations. These studies have become the primary data source for predicting higher level ecological effects, but the roles of intraspecific interactions in re-shaping biological, demographic and evolutionary responses are not commonly considered. To explore this problem, I assessed responses in the mysid Americamysis bahia to bubbling of CO2-enriched and un-enriched air into the seawater supply in flow-through aquariums. I conducted one experiment using isolated age cohorts and a separate experiment using intact populations. The seawater supply was continuously input from Narragansett Bay (Rhode Island, USA). The 28-day cohort study was maintained without resource or spatial limitations, whereas the 5-month population study consisted of stage-structured populations that were allowed to self-regulate. These differences are common features of experiments and were intentionally retained to demonstrate the effect of methodological approaches on perceptions of effect mechanisms. The CO2 treatment reduced neonate abundance in the cohort experiment (24% reduction due to a mean pH difference of −0.27) but not in the population experiment, where effects were small and were strongest for adult and stage 1 survival (3% change due to a mean pH difference of −0.25). I also found evidence of competition in the population exper

  13. Does leaf photosynthesis adapt to CO2-enriched environments? An experiment on plants originating from three natural CO2 springs.

    Science.gov (United States)

    Onoda, Yusuke; Hirose, Tadaki; Hikosaka, Kouki

    2009-01-01

    Atmospheric CO2 elevation may act as a selective agent, which consequently may alter plant traits in the future. We investigated the adaptation to high CO2 using transplant experiments with plants originating from natural CO2 springs and from respective control sites. We tested three hypotheses for adaptation to high-CO2 conditions: a higher photosynthetic nitrogen use efficiency (PNUE); a higher photosynthetic water use efficiency (WUE); and a higher capacity for carbohydrate transport from leaves. Although elevated growth CO2 enhanced both PNUE and WUE, there was no genotypic improvement in PNUE. However, some spring plants had a higher WUE, as a result of a significant reduction in stomatal conductance, and also a lower starch concentration. Higher natural variation (assessed by the coefficient of variation) within populations in WUE and starch concentration, compared with PNUE, might be responsible for the observed population differentiation. These results support the concept that atmospheric CO2 elevation can act as a selective agent on some plant traits in natural plant communities. Reduced stomatal conductance and reduced starch accumulation are highlighted for possible adaptation to high CO2.

  14. Geological Storage of CO2. Site Selection Criteria; Almacenamiento Geologico de CO2. Criterios de Selecci0n de Emplazamientos

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, C.; Martinez, R.; Recreo, F.; Prado, P.; Campos, R.; Pelayo, M.; Losa, A. de la; Hurtado, A.; Lomba, L.; Perez del Villar, L.; Ortiz, G.; Sastre, J.; Zapatero, M. A.; Suarez, I.; Arenillas, A.

    2007-09-18

    In year 2002 the Spanish Parliament unanimously passed the ratification of the Kyoto Protocol, signed December 1997, compromising to limiting the greenhouse gas emissions increase. Later on, the Environment Ministry submitted the Spanish National Assignment Emissions Plan to the European Union and in year 2005 the Spanish Greenhouse Gas market started working, establishing taxes to pay in case of exceeding the assigned emissions limits. So, the avoided emissions of CO2 have now an economic value that is promoting new anthropogenic CO2 emissions reduction technologies. Carbon Capture and Storage (CCS) are among these new technological developments for mitigating or eliminate climate change. CO2 can be stored in geological formations such as depleted oil or gas fields, deep permeable saline water saturated formations and unmailable coal seams, among others. This report seeks to establish the selection criteria for suitable geological formations for CO2 storage in the Spanish national territory, paying attention to both the operational and performance requirements of these storage systems. The report presents the physical and chemical properties and performance of CO2 under storage conditions, the transport and reaction processes of both supercritical and gaseous CO2, and CO2 trapping mechanisms in geological formations. The main part of the report is devoted to geological criteria at watershed, site and formation scales. (Author) 100 refs.

  15. Geological Storage of CO2. Site Selection Criteria; Almacenamiento Geologico de CO2. Criterios de Seleccion de Emplazamientos

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, C.; Martinez, R.; Recreo, F.; Prado, P.; Campos, R.; Pelayo, M.; Losa, A. de la; Hurtado, A.; Lomba, L.; Perez del Villar, L.; Ortiz, G.; Sastre, J.

    2006-07-01

    In year 2002 the Spanish Parliament unanimously passed the ratification of the Kyoto Protocol, signed December 1997, compromising to limiting the greenhouse gas emissions increase. Later on, the Environment Ministry submitted the Spanish National Assignment Emissions Plan to the European Union and in year 2005 the Spanish Greenhouse Gas market started working, establishing taxes to pay in case of exceeding the assigned emissions limits. So, the avoided emissions of CO2 have now an economic value that is promoting new anthropogenic CO2 emissions reduction technologies. Carbon Capture and Storage (CCS) are among these new technological developments for mitigating or eliminate climate change. CO2 can be stored in geological formations such as depleted oil or gas fields, deep permeable saline water saturated formations and unmineable coal seams, among others. This report seeks to establish the selection criteria for suitable geological formations for CO2 storage in the Spanish national territory, paying attention to both the operational and performance requirements of these storage systems. The report presents the physical and chemical properties and performance of CO2 under storage conditions, the transport and reaction processes of both supercritical and gaseous CO2, and CO2 trapping mechanisms in geological formations. The main part of the report is devoted to geological criteria at watershed, site and formation scales. (Author) 100 ref.

  16. Cost evaluation of CO2 sequestration by aqueous mineral carbonation

    Energy Technology Data Exchange (ETDEWEB)

    Huijgen, W.J.J. [Energy Research Centre of The Netherlands, P.O. Box 1, 1755 ZG Petten (Netherlands); Comans, R.N.J. [Wageningen University, Department of Soil Quality, P.O. Box 8005, 6700 EC Wageningen (Netherlands); Witkamp, G.J. [Delft University of Technology, Laboratory for Process Equipment, Leeghwaterstraat 44, 2628 CA Delft (Netherlands)

    2007-05-15

    A cost evaluation of CO2 sequestration by aqueous mineral carbonation has been made using either wollastonite (CaSiO3) or steel slag as feedstock. First, the process was simulated to determine the properties of the streams as well as the power and heat consumption of the process equipment. Second, a basic design was made for the major process equipment, and total investment costs were estimated with the help of the publicly available literature and a factorial cost estimation method. Finally, the sequestration costs were determined on the basis of the depreciation of investments and variable and fixed operating costs. Estimated costs are 102 and 77 euro/ton CO2 net avoided for wollastonite and steel slag, respectively. For wollastonite, the major costs are associated with the feedstock and the electricity consumption for grinding and compression (54 and 26 euro/ton CO2 avoided, respectively). A sensitivity analysis showed that additional influential parameters in the sequestration costs include the liquid-to-solid ratio in the carbonation reactor and the possible value of the carbonated product. The sequestration costs for steel slag are significantly lower due to the absence of costs for the feedstock. Although various options for potential cost reduction have been identified, CO2 sequestration by current aqueous carbonation processes seems expensive relative to other CO2 storage technologies. The permanent and inherently safe sequestration of CO2 by mineral carbonation may justify higher costs, but further cost reductions are required, particularly in view of (current) prices of CO2 emission rights. Niche applications of mineral carbonation with a solid residue such as steel slag as feedstock and/or a useful carbonated product hold the best prospects for an economically feasible CO2 sequestration process.

  17. CyclicCO2R: production of cyclic carbonates from CO2 using renewable feedstocks

    NARCIS (Netherlands)

    Kimball, E.; Schuurbiers, C.A.H.; Zevenbergen, J.F.; Håkonsen, S.F.; Heyn, R.; Offermans, W.; Leitner, W.; Ostapowicz, T.; Müller, T. E.; Mul, G.; North, M.; Ngomsik-Fanselow, A.F.; Sarron, E.; Sigurbjörnsson, O.; Schäffner, B.

    2013-01-01

    The consortium behind CyclicCO2R wants to kick-start the implementation of CO2 utilization technologies by converting CO2 into a high value-added product, thus providing a showcase that inspires industry to further develop technologies utilizing CO2 as a sustainable raw material and valorizing CO2

  18. CyclicCO2R: production of cyclic carbonates from CO2 using renewable feedstocks

    NARCIS (Netherlands)

    Kimball, E.; Schuurbiers, C.A.H.; Zevenbergen, J.F.; Håkonsen, S.F.; Heyn, R.; Offermans, W.; Leitner, W.; Ostapowicz, T.; Müller, T. E.; Mul, G.; North, M.; Ngomsik-Fanselow, A.F.; Sarron, E.; Sigurbjörnsson, O.; Schäffner, B.

    2013-01-01

    The consortium behind CyclicCO2R wants to kick-start the implementation of CO2 utilization technologies by converting CO2 into a high value-added product, thus providing a showcase that inspires industry to further develop technologies utilizing CO2 as a sustainable raw material and valorizing CO2 i

  19. Simulated effect of calcification feedback on atmospheric CO2 and ocean acidification

    Science.gov (United States)

    Zhang, Han; Cao, Long

    2016-01-01

    Ocean uptake of anthropogenic CO2 reduces pH and saturation state of calcium carbonate materials of seawater, which could reduce the calcification rate of some marine organisms, triggering a negative feedback on the growth of atmospheric CO2. We quantify the effect of this CO2-calcification feedback by conducting a series of Earth system model simulations that incorporate different parameterization schemes describing the dependence of calcification rate on saturation state of CaCO3. In a scenario with SRES A2 CO2 emission until 2100 and zero emission afterwards, by year 3500, in the simulation without CO2-calcification feedback, model projects an accumulated ocean CO2 uptake of 1462 PgC, atmospheric CO2 of 612 ppm, and surface pH of 7.9. Inclusion of CO2-calcification feedback increases ocean CO2 uptake by 9 to 285 PgC, reduces atmospheric CO2 by 4 to 70 ppm, and mitigates the reduction in surface pH by 0.003 to 0.06, depending on the form of parameterization scheme used. It is also found that the effect of CO2-calcification feedback on ocean carbon uptake is comparable and could be much larger than the effect from CO2-induced warming. Our results highlight the potentially important role CO2-calcification feedback plays in ocean carbon cycle and projections of future atmospheric CO2 concentrations. PMID:26838480

  20. Simulated effect of calcification feedback on atmospheric CO2 and ocean acidification

    Science.gov (United States)

    Zhang, Han; Cao, Long

    2016-02-01

    Ocean uptake of anthropogenic CO2 reduces pH and saturation state of calcium carbonate materials of seawater, which could reduce the calcification rate of some marine organisms, triggering a negative feedback on the growth of atmospheric CO2. We quantify the effect of this CO2-calcification feedback by conducting a series of Earth system model simulations that incorporate different parameterization schemes describing the dependence of calcification rate on saturation state of CaCO3. In a scenario with SRES A2 CO2 emission until 2100 and zero emission afterwards, by year 3500, in the simulation without CO2-calcification feedback, model projects an accumulated ocean CO2 uptake of 1462 PgC, atmospheric CO2 of 612 ppm, and surface pH of 7.9. Inclusion of CO2-calcification feedback increases ocean CO2 uptake by 9 to 285 PgC, reduces atmospheric CO2 by 4 to 70 ppm, and mitigates the reduction in surface pH by 0.003 to 0.06, depending on the form of parameterization scheme used. It is also found that the effect of CO2-calcification feedback on ocean carbon uptake is comparable and could be much larger than the effect from CO2-induced warming. Our results highlight the potentially important role CO2-calcification feedback plays in ocean carbon cycle and projections of future atmospheric CO2 concentrations.

  1. 低分压CO2回收新技术捕集水泥窑气中CO2的侧线试验%Bypass experiment for capturing CO2 from cement furnace flue gas by low pressure CO2 recovery technology

    Institute of Scientific and Technical Information of China (English)

    黄汉根

    2011-01-01

    A bypass experiment facility for capturing CO2 from cement furnace flue gas is designed. A self-developed blended amine is used for CO2 capturing. The experimental results show that the CO2 volume content in the purified gas is lower than 1.41%, while the CO2 purity of the product gas is higher than 99 %. Using this technology, CO2 emission reduction can be realized. At the same time, CO2 product with high purity can be produced. This technology can be used as an effective technological support for enterprises to reduce CO2 emission.%设计了一套水泥窑气CO2捕集的侧线试验装置,利用自主研发的复合胺溶剂捕集窑气中的CO2.试验结果表明.新型复合胺溶剂能使净化气中CO2体积分数降至1.41%以下,产品气中CO2体积分数达到99%以上.采用该技术,可实现CO2减排并获得高纯度的CO2产品气,为企业的CO2减排提供技术支持.

  2. Energy consumption and CO2 emissions in Iran, 2025.

    Science.gov (United States)

    Mirzaei, Maryam; Bekri, Mahmoud

    2017-04-01

    Climate change and global warming as the key human societies' threats are essentially associated with energy consumption and CO2 emissions. A system dynamic model was developed in this study to model the energy consumption and CO2 emission trends for Iran over 2000-2025. Energy policy factors are considered in analyzing the impact of different energy consumption factors on environmental quality. The simulation results show that the total energy consumption is predicted to reach 2150 by 2025, while that value in 2010 is 1910, which increased by 4.3% yearly. Accordingly, the total CO2 emissions in 2025 will reach 985million tonnes, which shows about 5% increase yearly. Furthermore, we constructed policy scenarios based on energy intensity reduction. The analysis show that CO2 emissions will decrease by 12.14% in 2025 compared to 2010 in the scenario of 5% energy intensity reduction, and 17.8% in the 10% energy intensity reduction scenario. The results obtained in this study provide substantial awareness regarding Irans future energy and CO2 emission outlines.

  3. CO2 Virtual Science Data Environment API

    Data.gov (United States)

    National Aeronautics and Space Administration — The CO2 Virtual Data Environment is a comprehensive effort at bringing together the models, data, and tools necessary to perform research on atmospheric CO2.This...

  4. Why capture CO2 from the atmosphere?

    National Research Council Canada - National Science Library

    Keith, David W

    2009-01-01

    Air capture is an industrial process for capturing CO2 from ambient air; it is one of an emerging set of technologies for CO2 removal that includes geological storage of biotic carbon and the acceleration of geochemical weathering...

  5. Plains Traveler

    Science.gov (United States)

    2006-01-01

    10 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a dust devil traveling across a plain west-southwest of Schiaparelli Crater, in far eastern Sinus Meridiani. The dust devil is casting a shadow toward the northeast, just south (below) of an egg-shaped crater. Location near: 6.4oS, 349.3oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Southern Summer

  6. Utopia Plain

    Science.gov (United States)

    2006-01-01

    5 March 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a dark-toned, cratered plain in southwest Utopia Planitia. Large, light-toned, windblown ripples reside on the floors of many of the depressions in the scene, including a long, linear, trough. Location near: 30.3oN, 255.3oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  7. Stomatal response of Pinus sylvestriformis to elevated CO2 concentrations during the four years of exposure

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yu-mei; HAN Shi-jie; LIU Ying; JIA Xia

    2005-01-01

    Four-year-old Pinus sylvestriformis were exposed for four growing seasons in open top chambers to ambient CO2 concentration (approx. 350 μmol·mol-1) and high CO2 concentrations (500 and 700 μmol·mol-1) at Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences at Antu Town, Jilin Province, China (42oN, 128oE). Stomatal response to elevated CO2 concentrations was examined by stomatal conductance (gs), ratio of intercellular to ambient CO2 concentration (ci/ca) and stomatal number. Reciprocal transfer experiments of stomatal conductance showed that stomatal conductance in high-[CO2]-grown plants increased in comparison with ambient-[CO2]-grown plants when measured at their respective growth CO2 concentration and at the same measurement CO2 concentration (except a reduction in 700 μmol·mol-1 CO2 grown plants compared with plants on unchambered field when measured at growth CO2 concentration and 350 μmol·mol-1CO2). High-[CO2]-grown plants exhibited lower ci/ca ratios than ambient-[CO2]-grown plants when measured at their respective growth CO2 concentration. However, ci/ca ratios increased for plants grown in high CO2 concentrations compared with control plants when measured at the same CO2 concentration. There was no significant difference in stomatal number per unit long needle between elevated and ambient CO2. However, elevated CO2 concentrations reduced the total stomatal number of whole needle by the decline of stomatal line and changed the allocation pattern of stomata between upper and lower surface of needle.

  8. Zn-Mn-Al层状水滑石基复合氧化物光催化还原二氧化碳%Photocatalytic Reduction of CO2 by Composite Oxide Derived from Zn-Mn-Al Ternary Layered Double Hydroxides

    Institute of Scientific and Technical Information of China (English)

    严彬彬; 金献华; 谭广华; 陈燕; 张丽

    2015-01-01

    ZnMnAl-LDHs have been prepared via hydrothermal method. ZnMnAl mixed-metal oxide photocatalyst was derived from a ternary hydrotalcite-like precursor followed by controllable calcination temperature. The as-prepared samples were characterized by X-ray diffraction (XRD). The effects of the molar ratio of metal ion in the material, calcination before and after and calcination temperature on the structure and morphology of the as-prepared samples were investigated in detail. The results indicated that a single layered double hydroxide (LDH) precursor leads to a well-crystalline ternary oxide photocatalyst. The photocatalyst shows superior photocatalytic reduction of CO2 compared to the photodegradation of methyl orange (MO) under simulated sunlight irradiation. When the mass ratio of NaOH to NaCO3 is 1.6:5.04, the amount of photocatalyst is 1 g/L, the highest methanol yield can be obtained in 6 hours, most chromatographic area reached 89.7%. The present work demonstrated their potential as photocatalysts for photocatalytic CO2 reduction.%采用水热法制备ZnMnAl-CO3类水滑石,再经焙烧制备纳米锌锰铝三元复合金属氧化物光催化剂.采用X射线衍射表征了催化剂的组成结构.在模拟太阳光下,通过光催化降解甲基橙和还原CO2来考察样品的光催化活性,并探讨论了各种金属离子比、焙烧前后及焙烧温度对光催化活性的影响.结果表明:当锌、锰和铝的摩尔比为3:1:1、400℃焙烧时所得的样品,具有很强的CO2还原活性,明显优于对甲基橙的降解.当NaOH与Na2SO3的质量比为1.6:5.04时,催化剂加入量为1g/L,反应6h所得CO2的主要还原产物甲醇最多,峰面积达89.7%,说明该样品对减排温室气体具有潜在的应用前景.

  9. Calculating subsurface CO2 storage capacities

    NARCIS (Netherlands)

    Meer, B. van der; Egberts, P.

    2008-01-01

    Often we need to know how much CO2 we can store in a certain underground space, or how much such space we need to store a given amount of CO2. In a recent attempt (Bradshaw et al., 2006) to list various regional and global estimates of CO2 storage capacity (Figure 1), the estimates reported are ofte

  10. Calculating subsurface CO2 storage capacities

    NARCIS (Netherlands)

    Meer, B. van der; Egberts, P.

    2008-01-01

    Often we need to know how much CO2 we can store in a certain underground space, or how much such space we need to store a given amount of CO2. In a recent attempt (Bradshaw et al., 2006) to list various regional and global estimates of CO2 storage capacity (Figure 1), the estimates reported are

  11. EVs and post 2020 CO2 targets for passenger cars

    NARCIS (Netherlands)

    Smokers, R.T.M.; Verbeek, M.; Zyl, S. van

    2013-01-01

    This paper analyses what post 2020 targets may be necessary for the European CO2 legislation for passenger cars in order to reach the overall sectoral goal of 60% reduction of transport's greenhouse gas emissions by 2050 relative to 1990, as defined in the European Commission's White Paper. The requ

  12. An overview on non-CO2 greenhouse gases

    NARCIS (Netherlands)

    Pulles, T.; Amstel, van A.R.

    2010-01-01

    Non-CO2 greenhouse gases, included in the Kyoto Protocol, are methane (CH4), nitrous oxide (N2O), hexafluorocarbons (HFC), perfluorinated compounds (PFC) and sulphur hexafluoride (SF6). Together they account for about 25% of the present global greenhouse gas emissions. Reductions in emissions of the

  13. Mineral CO2 sequestration by steel slag carbonation

    NARCIS (Netherlands)

    Huijgen, W.J.J.; Comans, R.N.J.

    2005-01-01

    Mineral CO2 sequestration, i.e., carbonation of alkaline silicate Ca/Mg minerals, analogous to natural weathering processes, is a possible technology for the reduction of carbon dioxide emissions to the atmosphere. In this paper, alkaline Ca-rich industrial residues are presented as a possible feeds

  14. CO2 exsolution - challenges and opportunities in subsurface flow management

    Science.gov (United States)

    Zuo, Lin; Benson, Sally

    2014-05-01

    for storage security. Falta et al. [2013] show that if carbonated brine migrates upwards and exsolution occurs, brine migration would be greatly reduced and limited by the presence of exsolved CO2 and the consequent low relatively permeability to brine. Similarly, if an exsolved CO2 phase were to evolve in seals, for example, after CO2 injection stops, the effect would be to reduce the permeability to brine and the CO2 would have very low mobility. This flow blocking effect is also studied with water/oil/CO2 [Zuo et al., 2013]. Experiments show that exsolved CO2 performs as a secondary residual phase in porous media that effectively blocks established water flow paths and deviates water to residual oil zones, thereby increasing recovery. Overall, our studies suggest that CO2 exsolution provides an opportunity for mobility control in subsurface processes. However, the lack of simulation capability that accounts for differences between gas injection and gas exsolution creates challenges for modeling and hence, designing studies to exploit the mobility reduction capabilities of CO2 exsolution. Using traditional drainage multiphase flow parameterization in simulations involving exsolution will lead to large errors in transport rates. Development of process dependent parameterizations of multiphase flow properties will be a key next step and will help to unlock the benefits from gas exsolution. ACKNOWLEDGEMENT This work is funded by the Global Climate and Energy Project (GCEP) at Stanford University. This work was also supported by U.S. EPA, Science To Achieve Results (STAR) Program, Grant #: 834383, 2010-2012. REFERENCES Falta, R., L. Zuo and S.M. Benson (2013). Migration of exsolved CO2 following depressurization of saturated brines. Journal of Greenhouse Gas Science and Technology, 3(6), 503-515. Zuo, L., S.C.M. Krevor, R.W. Falta, and S.M. Benson (2012). An experimental study of CO2 exsolution and relative permeability measurements during CO2 saturated water

  15. CO2 Capture for Cement Technology

    OpenAIRE

    2013-01-01

    Production of cement is an energy intensive process and is the source of considerable CO2emissions. Itis estimated that the cement industry contributes around 8% of total global CO2emissions. CO2is oneof the major greenhouse gases. In the atmosphere, the CO2concentration has increased from 310 ppmvin 1960 to 390 ppmv in 2012, probably due to human activity. A lot of research is being carried out forreducing CO2emissions from large stationary sources. Ofwhich, the carbonate looping process is ...

  16. Forest succession at elevated CO2

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Heterogeneous catalytic conversion of CO2: a comprehensive theoretical review

    Science.gov (United States)

    Li, Yawei; Chan, Siew Hwa; Sun, Qiang

    2015-05-01

    The conversion of CO2 into fuels and useful chemicals has been intensively pursued for renewable, sustainable and green energy. However, due to the negative adiabatic electron affinity (EA) and large ionization potential (IP), the CO2 molecule is chemically inert, thus making the conversion difficult under normal conditions. Novel catalysts, which have high stability, superior efficiency and low cost, are urgently needed to facilitate the conversion. As the first step to design such catalysts, understanding the mechanisms involved in CO2 conversion is absolutely indispensable. In this review, we have summarized the recent theoretical progress in mechanistic studies based on density functional theory, kinetic Monte Carlo simulation, and microkinetics modeling. We focus on reaction channels, intermediate products, the key factors determining the conversion of CO2 in solid-gas interface thermocatalytic reduction and solid-liquid interface electrocatalytic reduction. Furthermore, we have proposed some possible strategies for improving CO2 electrocatalysis and also discussed the challenges in theory, model construction, and future research directions.

  18. Continuous Vocalization during Kendo Exercises Suppresses Expiration of CO2.

    Science.gov (United States)

    Arikawa, H; Terada, T; Takahashi, T; Kizaki, K; Imai, H; Era, S

    2015-06-01

    One distinctive trait of kendo, the Japanese martial art of fencing, is the execution of sustained, high-effort vocalizations during actions. The purpose of this study was to determine the effect of these vocalizations on respiratory functions. First, the intensity of 3 kendo exercises was quantified by measuring oxygen uptake (V̇O2) and comparing it with V̇O2max measured during treadmill tests of 8 university kendo athletes. Respiratory variables of these 8 athletes were then analyzed using a portable breath gas analyzer during the most intensive kendo exercise, kakari-keiko, with and without vocalization. Breathing frequency (fB) increased regardless of vocalization, but in trials with vocalization, fB and ventilation were significantly lower, and expiration time was significantly longer. Components of expired gases were also affected by vocalization. Although there was no significant difference in oxygen uptake, vocalization yielded a reduction in carbon dioxide output (V̇CO2) and an increase in fraction of end-tidal carbon dioxide (FetCO2). We thus conclude that these vocalizations greatly affect expiration breathing patterns in kendo. Moreover, repetition of kakari-keiko caused a reduction in V̇CO2 and an increase in FetCO2 and CO2 storage. We consider the possibility that the sustained high-effort vocalizations of kendo also increase cerebral blood flow.

  19. Residual CO2 trapping in Indiana limestone.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  1. Amine scrubbing for CO2 capture.

    Science.gov (United States)

    Rochelle, Gary T

    2009-09-25

    Amine scrubbing has been used to separate carbon dioxide (CO2) from natural gas and hydrogen since 1930. It is a robust technology and is ready to be tested and used on a larger scale for CO2 capture from coal-fired power plants. The minimum work requirement to separate CO2 from coal-fired flue gas and compress CO2 to 150 bar is 0.11 megawatt-hours per metric ton of CO2. Process and solvent improvements should reduce the energy consumption to 0.2 megawatt-hour per ton of CO2. Other advanced technologies will not provide energy-efficient or timely solutions to CO2 emission from conventional coal-fired power plants.

  2. Reduction of soluble nitrogen and mobilization of plant nutrients in soils from U.S. northern Great Plains agroecosystems by phenolic compounds

    Science.gov (United States)

    Phenolic plant secondary metabolites actively participate in a broad range of important reactions that affect livestock, plants and soil. In soil, phenolic compounds can affect nutrient dynamics and mobility of metals but their role in northern Great Plains agroecosystems is largely unknown. We eval...

  3. Agroecosystem productivity in a warmer and CO2 enriched atmosphere

    Science.gov (United States)

    Bernacchi, Carl; Köhler, Iris; Ort, Donald; Long, Steven; Clemente, Thomas

    2017-04-01

    A number of in-field manipulative experiments have been conducted that address the response of key ecosystem services of major agronomic species to rising CO2. Global warming, however, is inextricably linked to rising greenhouse gases in general, of which CO2 is the most dominant. Therefore, agroecosystem functioning in future conditions requires an understanding of plant responses to both rising CO2 and increased temperatures. Few in-field manipulative experiments have been conducted that supplement both heating and CO2 above background concentrations. Here, the results of six years of experimentation using a coupled Free Air CO2 Enrichment (FACE) technology with variable output infrared heating arrays are reported. The manipulative experiment increased temperatures (+ 3.5˚ C) and CO2 (+ 200 μmol mol-1) above background levels for on two major agronomic crop species grown throughout the world, Zea mays (maize) and Glycine max (soybean). The first phase of this research addresses the response of plant physiological parameters to growth in elevated CO2 and warmer temperatures for maize and soybean grown in an open-air manipulative experiment. The results show that any increase in ecosystem productivity associated with rising CO2 is either similar or is offset by growth at higher temperatures, inconsistent with the perceived benefits of higher CO2 plus warmer temperatures on agroecosystem productivity. The second phase of this research addresses the opportunity to genetically modify soybean to allow for improved productivity under high CO2 and warmer temperatures by increasing a key photosynthetic carbon reduction cycle enzyme, SPBase. The results from this research demonstrates that manipulation of the photosynthetic pathway can lead to higher productivity in high CO2 and temperature relative to the wild-type control soybean. Overall, this research advances the understanding of the physiological responses of two major crops, and the impact on ecosystem services

  4. Extraction of stevia glycosides with CO2 + water, CO2 + ethanol, and CO2 + water + ethanol

    Directory of Open Access Journals (Sweden)

    A. Pasquel

    2000-09-01

    Full Text Available Stevia leaves are an important source of natural sugar substitute. There are some restrictions on the use of stevia extract because of its distinctive aftertaste. Some authors attribute this to soluble material other than the stevia glycosides, even though it is well known that stevia glycosides have to some extent a bitter taste. Therefore, the purpose of this work was to develop a process to obtain stevia extract of a better quality. The proposed process includes two steps: i Pretreatment of the leaves by SCFE; ii Extraction of the stevia glycosides by SCFE using CO2 as solvent and water and/or ethanol as cosolvent. The mean total yield for SCFE pretreatment was 3.0%. The yields for SCFE with cosolvent of stevia glycosides were below 0.50%, except at 120 bar, 16°C, and 9.5% (molar of water. Under this condition, total yield was 3.4%. The quality of the glycosidic fraction with respect to its capacity as sweetener was better for the SCFE extract as compared to extract obtained by the conventional process. The overall extraction curves were well described by the Lack extended model.

  5. 钢铁生产CO2过程排放分析%Analysis of CO2 emissions of iron and steel making process

    Institute of Scientific and Technical Information of China (English)

    卢鑫; 白皓; 赵立华; 李宁; 李洪福

    2012-01-01

    钢铁生产成为大气中温室气体CO2的一大来源,准确测算钢铁生产CO2过程排放量是评估企业或行业减排的保障.建立基于CO2排放模块的CO2排放模型,选定国内典型钢铁生产企业进行分析,发现炼铁工序的CO2排放占总流程的60%左右,同时进一步分析了整体CO2排放强度与吨钢能耗的关系及工序CO2排放强度的分布.%The iron and steel making process has become one of the main sources of greenhouse gas CO2 in atmosphere, and the accurate calculation of CO2 emission in iron and steel making process will be the foundation to evaluate the emission reduction of specific enterprise and industry. With the CO2 emission model based on the CO2 emission module and the data from the selective typical iron and steel making plants in China, it was found that the CO2 emission of iron making process account for about 60% of total emission. Further, the relationship between total CO2 emission intensity and energy consumption intensity and the distribution of different process CO2 emission were analyzed.