bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methanol from fossil and renewable resources
Authors: Edinger R. , Isenberg G. , Höhlein B. 
Published: December 2010

AbstractToday, methanol is primarily used for the purposes of the chemical industry. Methanol as an energy carrier and fuel option could enlarge our energy sources for future mobility. Since methanol can be derived from both fossil and renewable resources, it has the option of allowing an economically viable transition to CO2‐reduced mobility. Methanol from wastes, residues, and biomass could support the fuel market for industrialized and developing nations. For fuel cell vehicle applications, methanol constitutes a liquid fuel that can be conveniently stored under atmospheric conditions. For internal combustion and hybrid vehicle propulsion, blending methanol to conventional fuels promises higher fuel quality and, when produced from renewable resources, significantly lower carbon dioxide emissions in the well‐to‐wheel context. For providing future‐oriented transport and mobility, a fuel source shift from fossil to renewable resources is necessary to achieve global atmospheric protection goals as suggested by the United Nations and the European Union.
Solar and wind energy coupled with electrolysis and fuel cells
Authors: Wurster R. , Schindler J. 
Published: December 2010

Abstract
The types and typical capacity ranges of photovoltaic energy conversion, solar thermal electric power generation and wind power generation are outlined, including their respective energy generation costs. Energy potentials for solar and wind power generation suitable for renewable hydrogen production are presented for selected world key areas (North America, Europe and Asia) and illustrated in various tables.
All technologies directly and indirectly necessary for the generation of hydrogen from renewable electricity based energy sources are presented. This includes electricity transmission and conditioning; hydrogen production via electrolysis; hydrogen compression and compressed storage, respectively; its liquefaction and cryogenic storage; hydrogen transportation, either in compressed gaseous form through pipelines or in liquid form via tanker ship and trailers, and finally hydrogen use in fuel cells.

Centralized and distributed settings of renewable hydrogen generation and utilization are described with the focus on distributed settings. Wind/hydrogen energy systems in the 1 kW
e
–5 MW
e
capacity range are used as an example to explain the implications of system layouts for system availability, investment cost reduction and target markets.

Strategies for the build‐up of renewable electricity/hydrogen systems for power generation and fuel supply are developed, outlining in particular hydrogen's unique capability of facilitating the widespread introduction of a vehicle fuel of defined quality derived from renewable sources into future vehicle fuel markets. The requirements for a coordinated approach will be outlined.
Ammonia crackers
Authors: Hacker V. , Kordesch K. 
Published: December 2010

AbstractAnhydrous ammonia is discussed as an easy to handle and commercially widely available energy carrier. Facilities for storage and transport by sea and land from ammonia producers to major customers are available throughout the world. Pure liquid ammonia, stored in low pressure vessels, is comparable in energy density as well as in price with methanol. Ammonia is cracked on‐site or on‐board into hydrogen and nitrogen. Traces of residual ammonia in the feed stream have to be removed when an acidic electrolyte fuel cell is used. For alkaline fuel cells no gas purification is necessary.
Catalyst development for water–gas shift
Authors: Ladebeck J. R. , Wagner J. P. 
Published: December 2010

AbstractIn the industrial production of hydrogen and of synthesis gas the water gas shift reaction represents an essential step for the overall process efficiency of the process by increasing the hydrogen yield and by adjusting the desired ratio of hydrogen and carbon monoxide for a subsequent synthesis step. In addition to that in fuel cell technology it is absolutely necessary to decrease the CO content of the fuel hydrogen due to the limited CO tolerance of present day fuel cell anodes. To be successful applying water gas shift catalysts in hydrogen production for fuel cells especially in automotive systems some major obstacles of the commercial Cu/Zn/Al catalyst systems must be overcome. Major new demands are reduction of volume and weight by two to three orders of magnitude, oxidation resistance and improved tolerance for steam condensation and poisons, here mainly sulfur present in gas feedstock and in gasoline. Precious metal catalyst systems on rare earth metal oxides are most promising and could fulfill the requirements in nonstationary applications were conventional catalysts are not applicable.
PROXcatalysts
Authors: Shore L. , Farrauto R. J. 
Published: December 2010

AbstractThe proton exchange membrane fuel cell uses a Pt‐based catalytic anode and operates at about 80 °C. The hydrogen that is oxidized at the fuel cell anode can be obtained from reforming a hydrocarbon fuel. Depending on the reforming model, the hydrogen stream may initially contain almost 10% CO (dry basis). Since carbon monoxide adsorbs strongly on precious metals, one of the most important requirements for successful operation of this fuel cell is that the CO concentration be reduced to <10 ppm (99.99% conversion) to protect the Pt anode from CO poisoning and deactivation.The task of CO removal is a multi‐stage process within the fuel reformer. The primary CO converter is a water gas shift (WGS) reactor, where the CO is reacted with water to yield equimolar concentrations of CO2and H2. Because of both thermodynamic and kinetic limitations, WGS normally yields a stream with 0.2–0.5% CO. The most effective mechanism for further CO removal is oxidation with air injection. Because of the very high ratio of hydrogen to carbon monoxide (>100 : 1), the catalyst needs to be highly selective. Therefore, the process is called selective oxidation or preferential oxidation (PROX).The objective of the PROX reaction is high CO conversion to CO2without excessive hydrogen oxidation (to water). This article discusses the details of the PROX reaction, catalytic materials currently being investigated and alternative approaches to CO removal.
Hydrogen safety, codes and standards for vehicles and stationary applications
Authors: Scheffler G. , Wurster R. , Schindler J. 
Published: December 2010

Abstract
General safety characteristics and considerations of hydrogen systems are presented herein as they relate to fuel cell power generators.
The use of hydrogen in “town gas” dates back to the 1800s. From these early applications to current industrial and aerospace uses, an excellent safety record has been established with hydrogen. As we move forward towards new applications, it is essential that the developers of new equipment recognize the practices currently used by the hydrogen industry and adapt these practices to the development of new products. This article describes design processes and work practices required for the safe operation of hydrogen systems. Furthermore, relevant codes, standards and regulations are compiled and discussed from both North American and European perspectives.
In North America, standards already exist for industrial hydrogen systems and stationary fuel cell power plants. These standards are being revised to expand applicability and new standards are being written for new products, such as fuel cell powered vehicles and portables. Additionally, codes, standards and regulations are being developed to address the installation of hydrogen systems and fuel cell power plants.
Among the regulations and standards addressed from the European perspective are the International Organization for Standardization the International Electrotechnical Commission, European Commission Council Directives and European Accord Europeen Relatif au Transport International des Marchandises Dangereuses Par Route (ADR) regulations.
For vehicles and related infrastructure systems and components different regulations or standards are applicable. In North America, self‐certification is the standard procedure to bring vehicles on public roads, whereas in Europe, a whole vehicle type approval is performed either on the basis of an European Economic Community directive or an Economic Commission for Europe regulation, not based on any standards. For the future harmonized certification of hydrogen road vehicles in Europe, work initiated by the European Integrated Hydrogen Project are addressed.
For the approval of stationary hydrogen systems and components, as an example, German jurisdiction and permission procedures for hydrogen refueling stations, the applicable pressure vessel regulations, the type approval and recurrent testing are explained as required instruments.
Graphite–based bipolar plates
Authors: Roßberg K. , Trapp V. 
Published: December 2010

Abstract
Composites of polymer binders and conductive particles (e.g., graphite powder) are an interesting alternative bipolar plate material, since they are less expensive than pure graphite and less corrosion‐sensitive than metals. By appropriate choice of both components these composite materials can be tailored to meet the requirements of good high‐volume processability (e.g., by injection‐molding) and adequate behavior under fuel cell operation. Another graphite‐based bipolar plate material is graphite foil which is obtained by pressing expanded natural graphite. Both graphite based bipolar plate materials described in this chapter can be considered as “specialists” for different fuel cell applications. Graphite foil is especially attractive for lightweight fuel cell applications, e.g., in the portable and automotive field. For both kinds of bipolar plates, material issues are discussed and the processing technologies are described. Furthermore, techniques to reduce the contact resistance of molded graphite/polymer composite bipolar plates and to increase the gas‐tightness of graphite foil are indicated. The strong influence of the specifications of the starting materials and the processing conditions on the product quality is pointed out.
Ptalloys as oxygen reduction catalysts
Authors: Thompsett D. 
Published: December 2010

AbstractThe use of carbon‐supported Pt alloy catalysts for phosphoric acid fuel cells (PAFC) is well established. In comparison with Pt‐only catalysts, Pt alloy catalysts offer greater oxygen reduction activity and durability. In contrast, the introduction of Pt alloy catalysts for proton exchange membrane fuel cells (PEMFC) is in its infancy, despite having been shown to offer better performance to Pt‐only catalysts. Since the first reports of the use of Pt alloys as cathode catalysts in PEMFCs in 1992, surprisingly little further work has been reported. However, carbon‐supported Pt alloys have been shown to give superior performance to Pt in practical fuel cell hardware, as well as showing good durability. The mechanisms for enhanced activity of Pt alloys for oxygen reduction have been debated for the last 20 years, with many ideas proposed. However, more recently, the use of in situ characterization techniques, especially X‐ray adsorption spectroscopy, has shed light on the differences between Pt and Pt alloys at the potentials of oxygen reduction. It has been shown that alloys show differences in electronic and structural properties, as well as inhibited chemisorption of oxygenated species and stability of surfaces to reconstruction.
Manufacture of electrocatalyst powders by a spray‐based production platform
Authors: Hampden‐Smith M. , Atanassova P. , Atanassov P. , Kodas T. 
Published: December 2010

AbstractThis chapter describes a spray‐based method to manufacture electrocatalyst powders for fuel cell and related applications. The attributes of this process are compared to traditional solution precipitation/impregnation methods as well as non‐powder‐based electrocatalyst production methods. The spray‐based process described here results in formation of unique spherical, micrometer‐sized aggregates consisting of sub‐micrometer electrocatalyst particles where the nanometer sized active phases (Pt, PtRu, metal alloys, metal oxides, composite and anchored molecular compounds) are highly dispersed on the surface of carbon supports. The advantages of this method to manufacture electrocatalyst powders are described in terms of process economics and performance.
Mechanisms of membrane degradation
Authors: LaConti A. B. , Hamdan M. , McDonald R. C. 
Published: December 2010

AbstractIntroduction of proton‐exchange membranes as solid electrolytes has permitted the development of fuel cells that utilize hydrogen, reformate gas and methanol as reactants. Modern fuel cells have extended service life and reliability and increased power and energy density. The need for fuel cell operating in excess of 5000 h for transportation and 30 000 h for stationary applications has led to extensive investigations of the failure modes in an effort to understand the primary mechanical, chemical and electrochemical mechanisms. This chapter reviews the progress in understanding the limitations of fuel cell operation with historical and current state‐of‐the‐art membranes and suggests directions for achieving further improvement.
System design for vehicle applications:GM/opel
Authors: Masten D. A. , Bosco A. D. 
Published: December 2010

AbstractPolymer electrolyte membrane fuel cells (PEMFCs) offer the promise of low or emissions‐free, high efficiency vehicle power trains. However, many challenges and trade‐offs are inherent in the adoption of the PEMFC stack to a complete production automotive system. In this chapter, major vehicle requirements are considered. A brief survey of the characteristics of direct hydrogen fuel cell systems, some permutations to the basic system and the options available to a system designer, as well as a more detailed discussion of some of the key trade‐offs, are presented.
Special applications usingPEM‐technology
Authors: LaConti A. B. , Swette L. 
Published: December 2010

AbstractProton‐exchange or polymer electrolyte membrane (PEM) water electrolyzers, because of their superior performance reliability and long life, have been selected for use for advanced Navy and NASA oxygen life‐support applications. Some of the characteristics of PEM electrolyzers using liquid water anode or cathode feeds, as well as water vapor cathode feeds, are described. There has also been significant progress in the development of high‐energy‐density regenerative PEM fuel cells for NASA space and high‐altitude, solar‐powered aircraft applications. Small PEM electrolyzers that supply up to 1200 cm3H2 min−1have been sold commercially for over 25 years to replace gas cylinders and supply high‐purity hydrogen in laboratories and in the field for flame ionization detector‐based gas chromatographic applications. Also, larger PEM electrolyzers ranging from 1 m3H2 h−1to 20 m3H2 h−1have been sold commercially for cylinder replacement and on‐site hydrogen generation applications such as electrical generator cooling, electronic and metal processing and corrosion prevention. Recent emphasis has been on development of advanced water electrolyzers that generate hydrogen for storage at elevated pressure (up to 17.2 MPa) and oxygen at near‐ambient pressure. These advanced electrolyzers do not require a separate high‐pressure gas containment vessel or high‐pressure liquid water feed pump. Possible alternative applications of this technology are in the fuel cell and related fields for energy storage, power backup, power boosting and refueling. The extension of the above PEM technologies to some electrochemical gas concentrator/compressor applications is reviewed.
Transport/kinetic limitations and efficiency losses
Authors: Müller J. , Frank G. , Colbow K. , Wilkinson D. 
Published: December 2010

AbstractThe following contribution explores many of the fundamental aspects of the direct methanol fuel cell (DMFC). In particular, the electrochemical and physical processes that occur in the unit cell and the techniques used to study these phenomena are discussed. This information leads to a clearer picture of the breakdown and relative importance of the various contributions to the overall efficiency loss in a DMFC. The short introduction provides a brief perspective on the historical development of the DMFC and compares the present day performance to the conventional hydrogen/air fuel cell. A discussion of some of the analytical tools used to study the DMFC and probe the various processes, particularly under automotive operating conditions, follows. Techniques such as a.c. impedance spectroscopy under operating load conditions and gas chromatography for measuring methanol and carbon dioxide crossover, will be discussed in detail. The unit cell processes that typically dominate the performance characteristics of a DMFC under automotive operating conditions include: kinetic limitations at the anode and to a lesser extent at the cathode, mass transport limitations at the cathode and methanol and water crossover through the membrane from the anode to the cathode. By quantifying the various cell processes occurring by considering the overall mass flow and material balance, a more complete quantitative picture of the performance limitations of the DMFC expressed in terms of the relative contributions of the efficiency losses can be formulated. The contributions of the anode and cathode to the total efficiency losses are roughly comparable, unlike hydrogen/air fuel cells. Finally, in conclusion, this contribution will summarize some of the key findings and provide an outlook to the future.
New materials for
DMFC
MEAs
Authors: Neergat M. , Friedrich K. A. , Stimming U. 
Published: December 2010

Abstract
In recent years, the progress in the development of direct methanol fuel cells (DMFCs) for various applications has been enormous. It is probable that DMFC systems will soon be available as commercial products, especially in the low power range (<100 W). The materials currently used are, however, not optimized for the DMFC application. With this contribution we focus on the material aspects of the “active” components of the membrane electrode assembly (MEA). These components are the catalysts for the anode and cathode, the polymer membrane electrolyte and the diffusion layers. However, material issues regarding bipolar plates and other components of a stack are also discussed at the end of the review. After an introduction in which the basic concepts and processes of DMFCs are portrayed the main issues in DMFC development are discussed. Next, the specific demands that the materials must fulfil in DMFCs are presented. A discussion of the recent developments in membrane research and development follows, which is the crucial component regarding the goal to improve DMFC performance and fuel utilization. Therefore, we have devoted a considerable part of the chapter to this issue of new membrane materials. The catalysts and their reactivity are also an important issue in DMFC development. Both anode and cathode activities are crucial; we discuss mainly the systems that are already being used in MEAs. General considerations follow regarding electrode structure, catalyst utilization and porosity of the electrode. We also show in this contribution that besides the properties of the materials, the electrode structure also has a major influence on the processes in DMFCs.
DMFCsystem design for portable applications
Authors: Narayanan S. R. , Valdez T. I. , Rohatgi N. 
Published: December 2010

AbstractDirect methanol fuel cells (DMFCs) in portable applications are expected to provide substantially higher energy density and longer operating times over advanced batteries. The time threshold of advantage of using a fuel cell instead of a battery is almost independent of the power level, and is determined by the power density of the fuel cell and its operating efficiency. The various requirements for portable fuel cells that determine system design are defined with examples. The system design process and analysis methods are illustrated. The characteristics of cells and stacks required for system design are described. The dependence of DMFC stack performance on airflow rate, methanol concentration and temperature are necessary for developing closed loop mathematical models for system design. Such a closed loop system model has been developed and the consequences of varying airflow rate on water recovery, thermal management and overall system performance have been analyzed. Using this model, the effect of crossover rate on the overall efficiency, power density and the operating methanol concentrations have also been investigated. Effect of components on the overall power budget and design issues relating to start‐up and transient response are also discussed.
Electrolyte and material challenges
Authors: Hoffmann J. , Yuh C.‐Y. , Godula Jopek A. 
Published: December 2010

AbstractThis chapter sets its focus on the properties of known electrolytes as well as on new improved approaches. So far, most developers have favored two electrolyte mixtures, the lithium potassium carbonate (Li/K 62 : 38 mol%) and the lithium sodium carbonate (Li/Na 52 : 48 or 60 : 40 mol%). The published properties of these mixtures, in spite of the fact that many of them have been measured under different experimental conditions, are compared and discussed. The molten carbonate fuel cell (MCFC) community is separated into two main groups, which differ mainly in the gas compositions and utilization applied. Since the properties of the electrolyte are influenced significantly by these operating conditions, the electrolyte itself, which is in contact with most of the cell components, may also vary in how it interacts with the components. Therefore, the corrosion of the hardware material (bipolar plate, current collectors, electrodes, matrix, internal reforming catalyst), the evaporation of the electrolyte components and finally the electrochemical properties depend on the operation conditions and have a significant influence on the performance and lifetime of carbonate fuel cell systems. Experimental observations describing effects arising from interaction of the electrolyte with other components are also discussed in this chapter.
System design
Authors: Farooque M. , Ghezel‐Ayagh H. 
Published: December 2010

AbstractCarbonate fuel cell systems promise to provide high efficiency ultra‐clean power generation from a variety of gaseous, liquid and solid carbonaceous fuels. Designs of power generation units have been developed for natural gas, biogas, coal, ethanol and petroleum distillate fuels. The carbonate fuel cell, because of its high operating temperature (550–700 °C), allows significant system simplification by integrating the internal reforming feature into the fuel cell stack as well as use of the by‐product heat in an efficient bottoming cycle. Simple cycle sub‐megawatt and MW class natural gas systems promising efficiencies of 45–60% lowest heat value (LHV) are being developed for distributed power generation applications. Natural gas‐fueled power plant concepts with efficiencies over 70% (LHV) have also been developed using carbonate fuel cells integrated with gas turbines. The carbonate fuel cell system promises unique efficiency advantages with high carbon dioxide containing medium and low Btu fuels such as coal gas and biogas. This is in lieu of carbon dioxide being a reactant in carbonates fuel cells as opposed to other types of fuel cells. This advantage coupled with internal reforming capability allows configuration of high efficiency power plant systems based on the carbonate fuel cell.