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‣ Descarbonização do regime energetico dominante : perspectivas para a economia do hidrogenio no Brasil; Descarbonization of dominant energetic regime : perspectives on economy of hydrogen in Brazil

Sandra Simm Rohrich
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 11/08/2008 Português
Relevância na Pesquisa
37.463445%
Nas últimas décadas o desenvolvimento tecnológico do setor energético tem evoluído em relação às preocupações ambientais, sendo que estas também têm influenciado as opções por determinadas tecnologias energéticas. No contexto atual, os combustíveis fósseis e o motor de combustão caracterizam o regime energético dominante, realidade que apresenta constante crescimento no consumo de energia e leva a debates relacionados à segurança energética, ao esgotamento das fontes fósseis e à necessidade de descarbonizá-Ias. Por conseguinte, a necessidade de diminuir as emissões de C02 justifica a transição para opções energéticas mais amenas para o meio ambiente e que também possam fornecer energia para aplicações estacionárias e veiculares. A opção analisada nesta Tese é o hidrogênio como vetor energético e a célula a combustível como sistema de conversão, pressupondo que, se a inserção dessas tecnologias se efetivar, poderá influenciar toda a estrutura da sociedade e levar ao estabelecimento da Economia do Hidrogênio. Para tanto, as ações internacionais apresentam iniciativas oriundas da lnternational Partnership for the Hydrogen Economy (IPHE) e da lnternational Energy Agency (IEA). Ambas influenciam as orientações brasileiras provenientes das instituições de pesquisa e o desenvolvimento de políticas públicas. No Brasil existem dois documentos formais que tratam da Economia do Hidrogênio...

‣ Analise tecnica e economica da inserção da tecnologia de produção de hidrogenio a partir da reforma de etanol para geração de energia eletrica com celulas a combustivel; Technical and economical analysis of the introduction of the technology of hydrogen production from ethanol reforming for the generation of electric energy with fuel cells

Daniel Gabriel Lopes
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 19/02/2009 Português
Relevância na Pesquisa
37.3833%
Este trabalho apresenta uma análise técnica e econômica da utilização do processo de reforma de etanol para produção de hidrogênio e da utilização deste hidrogênio para produção de energia elétrica em uma célula a combustível do tipo PEMFC de 5,0 kW. A análise técnica se fundamenta em dados experimentais, inéditos, obtidos do protótipo de um reformador de etanol desenvolvido a partir de uma parceria entre o Laboratório de Hidrogênio da UNICAMP e a empresa Hytron, levando-se em consideração as principais características do funcionamento real do que representa o estado da arte desta tecnologia no Brasil. A metodologia utilizada para realização da análise econômica foi desenvolvida para se determinar os valores de referência relativos ao custo do hidrogênio produzido (30,34 R$/kg) e da energia elétrica gerada (2,30 R$/kWh) e indicar metas para a inserção futura destas tecnologias. Os resultados obtidos permitiram que se concluísse que os atuais custos de geração do hidrogênio produzido pelo protótipo do reformador de etanol são economicamente competitivos, assim como o custo de geração da energia elétrica com utilização deste hidrogênio na célula a combustível quando comparado com a aplicação de outras tecnologias alternativas...

‣ Influence of disinfectant technologies on red bell peppers safety

Alexandre, E. M. C.; Fundo, J. F.; Pedro, D. Santos; Brandão, T. R. S.; Silva, C. L. M.
Fonte: Universidade Católica Portuguesa Publicador: Universidade Católica Portuguesa
Tipo: Conferência ou Objeto de Conferência
Publicado em //2006 Português
Relevância na Pesquisa
37.440562%
The development of innovative technologies, promoting fruits and vegetables safety to reduce the risk of related food-borne diseases, is an actual concern. Several sanitizing agents for washing fruits and vegetables may be used to reduce the risk of microbial contamination. Traditional washing technologies utilize chlorine and hydrogen peroxide as sanitizing agents for fresh produce. More recently, ozone is being used as an innovative food processing technology that guarantees product safety, also increasing shelf life of fruits and vegetables. Its main advantage, when compared to traditional disinfectant technologies, relies on its potent antimicrobial action and non-toxic products decomposition. The objective of this work was to study the effectiveness of three sanitizing agents (sodium hypochlorite - used in a commercial available solution AMUKINA, hydrogen peroxide and ozone in aqueous solutions), on the reduction of Listeria innocua inoculated on red bell peppers. Results showed that ozone treatment allowed bacteria reductions identical to the ones attained with the traditional disinfectant solutions. On average, aqueous ozone allowed a decimal reduction of 2 cycles in Listeria innocua counts.

‣ Environmental impact of road transport in Portugal and effects of hydrogen technologies penetration

Travassos, Maria Antónia; Sá, A. I. Correia de; Luz, Paulo P. da; Rangel, C. M.
Fonte: International Workshop,Advances in Fuel Cells and the Hydrogen Economy Publicador: International Workshop,Advances in Fuel Cells and the Hydrogen Economy
Tipo: Conferência ou Objeto de Conferência
Publicado em 15/02/2008 Português
Relevância na Pesquisa
67.326904%
Road traffic is one of the transportation sectors with faster growth due to the of vehicle fleets increase and a strong investment in road infrastructure and also one of the most important emitters of greenhouse gases (GHGs).With introduction, in this sector, of a new renewable fuel, like hydrogen, a reduction of the reported pollutant is foreseen. In this work, an analysis of the environmental benefits resulting from the introduction of hydrogen on road transport in Portugal is made. Impact is analyzed mainly looking at the pollutant emissions provided by road transport at the point of use. The software chosen to calculate the emissions associated to road transport is the COPERT program (version IV) since it provides a detailed methodology for each specific pollutant related to the vehicle fleet of a region or country, as well as the driving conditions and fuel consumption.

‣ Penetration of hydrogen technologies: study on the environmental impact of road transport in Portugal

Travassos, Maria Antónia; Sá, A. I. Correia de; Luz, Paulo P. da; Rangel, C. M.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em 24/09/2008 Português
Relevância na Pesquisa
57.28506%
Road traffic is one of the transportation sectors with faster growth and also one of the most important emitters of greenhouse gases (GHGs). In this work, an analysis of the environmental benefits resulting from the introduction of hydrogen on road transport in Portugal is made. Impact is analyzed mainly looking at the pollutant emissions provided by road transport at the point of use. Emissions associated to road transport have been estimated using the software COPERT (version 4), since it provides a detailed methodology for each specific pollutant related to the vehicle fleet of a region or country, as well as the driving conditions and fuel consumption. Passenger cars, light duty vehicles and public transport buses are the vehicles categories in which the hydrogen technology is foreseen. The hydrogen penetration rates (moderate and high) are extracted from the European Project HYWAYS. Two trends are then considered, which give penetration rates of 40.0 % and 74.5 % in 2050 for the moderate and high scenarios respectively.

‣ Hydrogen energy power system for a stand-alone weekend-home application

Rangel, C. M.; Bozukov, Latchezar N.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em 01/04/2009 Português
Relevância na Pesquisa
37.221348%
With an increase in renewable energies penetration and a market potential for the introduction of hydrogen into stand-alone energy systems, aspects related with the immaturity of some of the technologies which integrate the hydrogen sub-system, represent important unresolved technical issues, entailing unavailable components or availability at high costs. As a consequence, there is a growing initiative in the development and implementation of such a systems, that may demonstrate improved energy efficiency, response time, and safety in the storage option looking for an increase in the energy round-trip efficiency of the hydrogen subsystem. In this work, a novel demonstration of a Hydrogen Weekend Bungalow powered as a standalone renewable hydrogen energy system is presented. The main system components are: 1.25 kW PV Solar Panel with DC- hydrogen generator; 10 Nm3 Hydrogen Storage tank on the base of metal hydrides; Novel Hydrogen Cooker - 2 x 1000W and Hydrogen Refrigerator –power - 50W; Fuel Cell 500 – 1000 W with Converter - 48 V DC - 220 VAC, 1.5 kW ; Hydrogen and water control system. During the day, electricity from PV panels is collected and stored as hydrogen. The Fuel Cell is supplied from hydrogen from a vessel containing a metallic hydride storage solution. The hydrogen storage tank is able to supply a novel Hydrogen Kitchen and Fuel Cell with hydrogen for production of minimum 10 kWh electricity and/or 20 kWh thermal power in total. Hydrogen can be directly converted to thermal energy by hydrogen burners being of a simple...

‣ Hydrogen production by alkaline water electrolysis

Santos,Diogo M. F.; Sequeira,César A. C.; Figueiredo,José L.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 Português
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37.43217%
Water electrolysis is one of the simplest methods used for hydrogen production. It has the advantage of being able to produce hydrogen using only renewable energy. To expand the use of water electrolysis, it is mandatory to reduce energy consumption, cost, and maintenance of current electrolyzers, and, on the other hand, to increase their efficiency, durability, and safety. In this study, modern technologies for hydrogen production by water electrolysis have been investigated. In this article, the electrochemical fundamentals of alkaline water electrolysis are explained and the main process constraints (e.g., electrical, reaction, and transport) are analyzed. The historical background of water electrolysis is described, different technologies are compared, and main research needs for the development of water electrolysis technologies are discussed.

‣ Prioritisation of Research and Development for modelling the safe production, storage, delivery and use of hydrogen.

BARALDI Daniele; PAPANIKOLAOU EFTHYMIA; HEITSCH Matthias; MORETTO Pietro; CANT Stewart; ROEKAERTS Dirk; DOROFEEV Sergey; KOTCHOURKO Alexei; MIDDHA Prankul; TCHOUVELEV Andrej; LEDIN Stephan; WEN Jennifer; VENETSANOS Alexandros; MOLKOV Vladimir
Fonte: Publications Office of the European Union Publicador: Publications Office of the European Union
Tipo: JRC Reference Reports Formato: Printed
Português
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37.792827%
Hydrogen is expected to play an important role in the energy mix of a future low carbon society, (the European Strategic Energy Technology Plan of the European Commission (COM 2007 - 723) and in the Hydrogen, Fuel Cells & Infrastructure Technologies Program-Multi-Year Research, Development, and Demonstration Plan of the USA Department of Energy (DoE 2007). Hydrogen safety issues must be addressed in order to ensure that the wide spread deployment and use of hydrogen and fuel cell technologies can occur with the same or lower level of hazards and associated risk compared to the conventional fossil fuel technologies. Hydrogen safety is a EU Policy relevant issue as it is stated in the priority 3 Action 2 (Continuous improvement in safety and security) of the EU “Energy 2020 A strategy for competitive, sustainable and secure energy”: “The same security and safety considerations will also be upheld in the development and deployment of new energy technologies (hydrogen safety, safety of CO2 transportation network, CO2 storage, etc…)” Computational Fluid Dynamics (CFD) is one of the tools to investigate safety issues related to the production, storage, delivery and use of hydrogen. CFD techniques can provide a wealthy amount of information on the dynamics of hypothetical hydrogen accident and its consequences. The CFD-based consequence analysis is then used in risk assessments. This report describes the output of a workshop organised at the Institute for Energy and Transport (JRC) in Petten...

‣ The hydrogen value chain: applying the automotive role model of the hydrogen economy in the aerospace sector to increase performance and reduce costs

FRISCHAUF NORBERT; ACOSTA IBORRA Beatriz; HARSKAMP Frederik; MORETTO Pietro; MALKOW Thomas; HONSELAAR M; STEEN Marc; HOVLAND Scott; HUFENBACH Bernhard; SCHAUTZ Max; WITTIG Manfred; SOUCEK Alexander
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Articles in Journals Formato: Online
Português
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Hydrogen will assume a key role in Europe’s effort to adopt its energy dependent society to satisfy its needs without releasing vast amounts of greenhouse gases. The paradigm shift is so paramount that one speaks of the ‘‘Hydrogen Economy’’, as the energy in this new and ecological type of economy is to be distributed by hydrogen. However, H2 is not a primary energy source but rather an energy carrier, a means of storing, transporting and distributing energy, which has to be generated by other means. Various H2 storage methods are possible; however industries’ favourite is the storage of gaseous hydrogen in high pressure tanks. The biggest promoter of this storage methodology is the automotive industry, which is currently preparing for the generation change from the fossil fuel internal combustion engines to hydrogen based fuel cells. The current roadmaps foresee a market roll-out by 2015, when the hydrogen supply infrastructure is expected to have reached a critical mass. The hydrogen economy is about to take off as being demonstrated by various national mobility strategies, which foresee several millions of electric cars driving on the road in 2020. Fuel cell cars are only one type of ‘‘electric car’’, battery electric as well as hybrid cars – all featuring electric drive trains – are the others. Which type of technology is chosen for a specific application depends primarily on the involved energy storage and power requirements. These considerations are very similar to the ones in the aerospace sector...

‣ SELECTIVITY AND RESISTANCE TO POISONS OF COMMERCIAL HYDROGEN SENSORS

PALMISANO VALERIO; WEIDNER RONNEFELD Eveline; BRETT Lois; BONATO CHRISTIAN; HARSKAMP Frederik; MORETTO Pietro; POST Matthew; BURGESS Robert; RIVKIN Carl; BUTTNER William
Fonte: Committee of WHEC2014 Publicador: Committee of WHEC2014
Tipo: Articles in periodicals and books Formato: Online
Português
Relevância na Pesquisa
37.358542%
The European Commission and the U.S. Department of Energy both recognize the key role hydrogen technologies will play in securing a safe, clean and secure energy supply in the future. Considering the potential implications on the safety and operation of hydrogen applications, the selectivity and resistance to poisoning of hydrogen sensors is a valid concern of the sensor user. The resistance of hydrogen sensors to chemical contaminants such as SO2, H2S, NO2 and hexamethyldisiloxane (HMDS) has been investigated for catalytic, MOSFET, electrochemical and thermal conductivity sensors [1,2]. These sensor platforms are among the most commonly used for the detection of hydrogen. The evaluation protocols were based on the recommendations of ISO 26142 [3]. Permanent alteration of the sensor response to the target analyte (H2) was rarely observed following exposure to potential poisons at the concentrations specified. Although a shift in the baseline response was often observed during exposure to the potential poisons, only in a few cases did this shift persist after removal of the contaminants. Overall, the resistance to poisoning of the sensors was good. However, a change in sensitivity to hydrogen was observed in the electrochemical platform after exposure to NO2 and for a catalytic sensor during exposure to SO2.; JRC.F.2-Energy Conversion and Storage Technologies

‣ Membrane technologies for hydrogen and carbon monoxide recovery from residual gas streams; Tecnologías de membranas para la recuperación de hidrógeno y monóxido de carbono de gases residuales

David, Oana Cristina
Fonte: Universidad de Cantabria Publicador: Universidad de Cantabria
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
37.1416%
ABSTRACT: This PhD thesis work is aimed to the separation and recovery of valuable gases from industrial residual gas streams by means of membrane technology. In this thesis, a case of study is defined as the tail gas generated in the manufacturing of carbon black. It is envisaged that membrane technology will allow to obtain H2 enriched permeate stream when polymeric membranes are used and CO can be obtained as permeate gas stream when facilitated transport - supported liquid membranes are used. Chapter I of this thesis gives a brief introduction over different gas separation methods and shows the industrial sources and importance of H2 and CO. Chapter II and III of this thesis deal with the study of polymeric membrane based separation of hydrogen from mixed gas streams composed of H2, CO, N2 and CO2 at different operation conditions, using dense and hollow fiber membranes prepared with a commercial glassy polymer, Matrimid. In chapter IV a comprehensive look at the reaction mechanism and the equilibrium parameters obtained from the experimental characterization of the physical and chemical solubility of carbon monoxide 1-Hexyl-3-methylimidazolium chlorocuprate ionic liquid is presented. Finally, in Chapter V overall conclusions of the entire work are made. Also prospects for further research are included.; RESUMEN: Esta tesis doctoral está enfocada hacia la separación y recuperación de hidrogeno y monóxido de carbono de efluentes gaseosos residuales procedentes de procesos industriales de combustión mediante la tecnología de membranas. Se ha definido como caso de estudio la corriente de gases generada en la fabricación de negro de carbono. Se espera que el uso de tecnologías de separación con membranas permita obtener en el lado del permeado de la membrana una corriente enriquecida en hidrógeno al emplear una membrana polimérica y una corriente enriquecida en monóxido de carbono mediante el transporte facilitado a través de una membrana líquida soportada. El Capítulo I de la tesis contiene una introducción sobre los distintos métodos de separación de gases y presenta las fuentes e importancia industrial de H2 y CO. Los capítulos II y III de la tesis abarcan el estudio de la separación selectiva de hidrógeno a partir de corrientes gaseosas compuestas por mezclas de H2...

‣ Ultrapurificación de peróxido de hidrógeno; Ultrapurification of hydrogen peroxide

Abejón Elías, Ricardo
Fonte: Universidade de Cantabria Publicador: Universidade de Cantabria
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
37.152383%
RESUMEN: El descubrimiento y empleo de los semiconductores ha influido de forma decisiva en las profundas modificaciones que han vivido las sociedades avanzadas como consecuencia de la revolución tecnológica de la segunda mitad del siglo XX. De este modo se ha configurado la actual sociedad global, donde las tecnologías de la información y la comunicación se han constituido como el elemento característico e imprescindible del desarrollo científico y tecnológico en el que se basan las actuales formas de vida. Las industrias que emplean materiales semiconductores o fabrican productos basados en los mismos demandan reactivos de calidad electrónica caracterizados por su limitado contenido en impurezas. Entre los reactivos de este tipo con mayor demanda se encuentra el peróxido de hidrógeno. Los procesos de ultrapurificación de peróxido de hidrógeno son necesarios para poder alcanzar los niveles de calidad exigidos por el sector, específicamente en lo referido a impurezas metálicas. La revisión del estado del arte con respecto a las tecnologías disponibles para la ultrapurificación de peróxido de hidrógeno presenta diferentes alternativas que incluyen la destilación, la adsorción, el intercambio iónico y las tecnologías de membranas. El empleo de membranas de ósmosis inversa aparece como una opción prometedora desde el punto de vista del uso más sostenible de los recursos naturales (materiales...

‣ Research Priorities and Progress in Hydrogen Energy Research in the EU

MORETTO PIETRO; MARTIN-BERMEJO Joaquin
Fonte: J. Wiley & Sons Publicador: J. Wiley & Sons
Tipo: Articles in books Formato: Printed
Português
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37.3833%
The European Commission (EC) fosters and funds under its multi-annual work programme - currently the Seventh Framework Programme (2007-1013) - research, development and demonstration activities on hydrogen and fuel cells. It has also successfully mobilised key European stakeholders via the establishment and operation of the industry-led European Hydrogen and Fuel Cell Technology Platform and most recently with the launching of its follow-up, the Fuel Cells and Hydrogen Joint Technology Initiative (JTI), a long-term public-private Joint Undertaking to be funded by the European community and an Industry Grouping. . The aim of this joint undertaking is through integrated, focused actions to explore the potential and accelerate the development and deployment of these key technologies at European level, with a vision of clean, affordable and secure energy systems based on hydrogen as an energy carrier and fuel cells as energy converters. The presentation highlights some illustrative EC co-financed R&D projects on hydrogen technologies and their key achievements. It also includes a brief overview of the enabling supporting functions assumed in this research field by the Commission's Joint Research Centre and in particular by the Institute for Energy. An outlook on hydrogen energy research and respective priorities in the Seventh Framework Programme and under the Fuel Cells and Hydrogen JTI...

‣ Viability of Current and Emerging Technologies for Domestic Solid Waste Treatment and Disposal : Implications on Dioxin and Furan Emissions

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Economic & Sector Work :: Other Environmental Study; Economic & Sector Work
Português
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37.42664%
This study was undertaken to identify and assess the technologies available worldwide for treatment and disposal of municipal solid waste (MSW), and to make a general assessment of the applicability of these technologies to various waste management 'settings' within the Latin American and Caribbean (LAC) Region. Each technology was evaluated for a number of key attributes, including demonstrated commercial viability, economics, institutional factors, sustainability metrics, and environmental attributes, including emissions of dioxins and furans. The study focused on the waste treatment technologies that have been commercially demonstrated worldwide; however, selected alternative and emerging technologies were also considered. After profiling the available waste management technologies, an assessment was then made of the general applicability of these technologies to various characteristic settings found within the LAC region. Technology applicability assessment at specific locations within the LAC region will require detailed...

‣ Technical and Economic Assessment of Off-grid, Mini-grid and Grid Electrification Technologies

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Publications & Research :: ESMAP Paper; Publications & Research
Português
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37.42664%
This report is part of the Energy and Water Department's commitment to providing new techniques and knowledge which complement the direct investment and other assistance to electrification as provided by the International Bank for Reconstruction and Development (IBRD) and the International Development Association (IDA). The purpose of this report is to convey the results of an assessment of the current and future economic readiness of electric power generation alternatives for developing countries. The objective of the technical and economic assessment was to systematically characterize the commercial and economic prospects of renewable and fossil fuel-fired electricity generation technologies now, and in the near future. The study was designed to cover the widest possible range of electrification applications faced by energy services delivery and power system planners, whether supply is provided through grid networks or stand-alone or mini-grid configurations. The assessment was conducted using a standard approach and is presented in a consistent fashion for each power generation technology configuration. The assessment time frame includes current status and forecast development trends over the period 2005-15...

‣ Advanced Biofuel Technologies : Status and Barriers

Cheng, Jay J.; Timilsina, Govinda R.
Fonte: Banco Mundial Publicador: Banco Mundial
Tipo: Publications & Research :: Policy Research Working Paper
Português
Relevância na Pesquisa
37.161313%
Large-scale production of crop based (first generation) biofuels may not be feasible without adversely affecting global food supply or encroaching on other important land uses. Because alternatives to liquid fossil fuels are important to develop in order to address greenhouse gas mitigation and other energy policy objectives, the potential for increased use of advanced (non-crop, second generation) biofuel production technologies has significant policy relevance. This study reviews the current status of several advanced biofuel technologies. Technically, it would be possible to produce a large portion of transportation fuels using advanced biofuel technologies, specifically those that can be grown using a small portion of the world's land area (for example, microalgae), or those grown on arable lands without affecting food supply (for example, agricultural residues). However, serious technical barriers limit the near-term commercial application of advanced biofuels technologies. Key technical barriers include low conversion efficiency from biomass to fuel...

‣ Prospects for hydrogen storage in graphene

Tozzini, Valentina; Pellegrini, Vittorio
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/07/2012 Português
Relevância na Pesquisa
37.173948%
Hydrogen-based fuel cells are promising solutions for the efficient and clean delivery of electricity. Since hydrogen is an energy carrier, a key step for the development of a reliable hydrogen-based technology requires solving the issue of storage and transport of hydrogen. Several proposals based on the design of advanced materials such as metal hydrides and carbon structures have been made to overcome the limitations of the conventional solution of compressing or liquefying hydrogen in tanks. Nevertheless none of these systems are currently offering the required performances in terms of hydrogen storage capacity and control of adsorption/desorption processes. Therefore the problem of hydrogen storage remains so far unsolved and it continues to represent a significant bottleneck to the advancement and proliferation of fuel cell and hydrogen technologies. Recently, however, several studies on graphene, the one-atom-thick membrane of carbon atoms packed in a honeycomb lattice, have highlighted the potentialities of this material for hydrogen storage and raise new hopes for the development of an efficient solid-state hydrogen storage device. Here we review on-going efforts and studies on functionalized and nanostructured graphene for hydrogen storage and suggest possible developments for efficient storage/release of hydrogen at ambient conditions.

‣ Structure and Morphology Control in Carbon Nanomaterials for Nanoelectronics and Hydrogen Storage

McNicholas, Thomas Patrick
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação Formato: 72691400 bytes; application/pdf
Publicado em //2009 Português
Relevância na Pesquisa
37.149727%

Carbon nanomaterials have a wide range of promising and exciting applications. One of the most heavily investigated carbon nanomaterial in recent history has been the carbon nanotube. The intense interest in carbon nanotubes can be attributed to the many exceptional characteristics which give them great potential to revolutionize modern mechanical, optical and electronic technologies. However, controlling these characteristics in a scalable fashion has been extremely difficult. Although some progress has been made in controlling the quality, diameter distribution and other characteristics of carbon nanotube samples, several issues still remain. The two major challenges which have stood in the way of their mainstream application are controlling their orientation and their electronic characteristics. Developing and understanding a Chemical Vapor Deposition based carbon nanotube synthesis method has been the major focus of the research presented here. Although several methods were investigated, including the so-called "fast-heating, slow-cooling" and large feeding gas flowrate methods, it was ultimately found that high-quality, perfectly aligned carbon nanotubes from a variety of metal catalysts could be grown on quartz substrates. Furthermore...

‣ Vehicle & infrastructure relationships in hydrogen transportation networks: Development of the H2VISION modeling tool

Meyer, Patrick
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado Formato: 2275415 bytes; application/pdf
Português
Relevância na Pesquisa
47.208203%
The political instability of acquiring oversea oil resources, the need to reduce greenhouse gas emissions, and the desire for inexpensive energy have recently driven a shift of focus towards hydrogen energy. It has become increasingly evident that there are significant barriers facing the development of a hydrogen-based energy system – a system commonly referred to as the “hydrogen economy”. The small quantities of hydrogen fuel cell vehicles that have been deployed to date are not numerous enough to facilitate the growth of a substantial refueling infrastructure. Additionally, the underdeveloped and extremely limited infrastructure has imposed significant convenience costs upon consumers. These convenience costs, in turn, inhibit further purchases of hydrogen fuel cell vehicles – creating what has been dubbed the “chicken and egg” phenomenon. To analyze the vehicle-infrastructure chicken and egg phenomenon and assist in the creation of future hydrogen-related policies, this thesis presents the H2VISION systems model. H2VISION is designed to explore: (1) the role of various government policies aimed at hydrogen deployment (vehicle procurement, monetary incentives, or mass-station building); (2) the specific role of government as a first-use and innovative adopter of hydrogen technologies; (3) the effect of consumer preferences regarding vehicles and convenience costs regarding infrastructure on hydrogen markets; and (4) the short- and long-term results of mainstream hydrogen technology diffusion. Using H2VISION...

‣ Environmental impact assessment of the penetration of hydrogen technologies in Portugal's road transport

Travassos, Maria Antónia; Sá, A. I. Correia de; Luz, Paulo P. da; Rangel, C. M.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em 01/04/2009 Português
Relevância na Pesquisa
57.28506%
Road traffic is one of the transportation sectors with faster growth and also one of the most important emitters of greenhouse gases (GHGs). In this work, an analysis of the environmental benefits resulting from the introduction of hydrogen on road transport in Portugal is made. Impact is analyzed mainly looking at the pollutant emissions provided by road transport at the point of use. Emissions associated to road transport have been estimated using the software COPERT (version 4), since it provides a detailed methodology for each specific pollutant related to the vehicle fleet of a region or country, as well as the driving conditions and fuel consumption. Passenger cars, light duty vehicles and public transport buses are the vehicles categories in which the hydrogen technology is foreseen. The hydrogen penetration rates (moderate and high) are extracted from the European Project HYWAYS. Two trends are then considered, which give penetration rates of 40.0 % and 74.5 % in 2050 for the moderate and high scenarios respectively.