Discovering the Mechanism of H2 Adsorption on Aromatic Carbon Nanostructures to Develop Adsorbents for Vehicular Applications

2004 ◽  
Vol 837 ◽  
Author(s):  
A. C. Dillon ◽  
J. L. Blackburn ◽  
P. A. Parilla ◽  
Y. Zhao ◽  
Y-H. Kim ◽  
...  
Keyword(s):  
Binding Energy ◽  
Hydrogen Storage ◽  
Carbon Nanostructures ◽  
Hydrogen Adsorption ◽  
Iron Catalyst ◽  
The United States ◽  
Department Of Energy ◽  
United States Department ◽  
Iron Particles ◽  
Aromatic Carbon

ABSTRACTHydrogen adsorption has been observed with a binding energy of ∼ 50 kJ /mol on as-synthesized carbon multi-wall nanotubes (MWNTs). The MWNTs are virtually free of non-nanotube carbon impurities but contain residual iron catalyst particles. The MWNTs are also highly graphitic. No hydrogen adsorption is observed at near ambient temperatures for purified MWNTs that are free of iron particles. However, hydrogen adsorption is also not observed on bare iron particles even following reduction in the presence of hydrogen at 775 K. These results imply that a special synergy occurs when small iron particles or atoms are in intimate contact with sp2-hybridized aromatic carbon. Interestingly, reducing the as-synthesized MWNTs in H2 at 573 K results in an increased hydrogen capacity. Understanding this hydrogen storage mechanism could facilitate the economical engineering of a hydrogen storage material that meets the United States Department of Energy targets for vehicular fuel cell applications. Recent theoretical studies have shown that an iron ad atom forms a complex with a C36 fullerene and shares charge with four carbon atoms of a bent five-membered ring. Three H2 ligands then coordinate with the iron forming a stable 18-electron organometallic complex. Here the binding energy of the molecular hydrogen ligands is ∼43 kJ /mol. These theoretical results could possibly explain the unique hydrogen storage properties of MWNTs that are grown with an iron catalyst.

Study of the Influence of the V in the Zr2Fe Alloy from Hydrogen Storage on Thermodynamic Properties

2019 ◽  
Vol 31 ◽  
pp. 22-29 ◽  
Author(s):  
Alejandro Martinez ◽  
Darío Peña ◽  
Daniela Bellon
Keyword(s):  
Solid State ◽  
Hydrogen Storage ◽  
Room Temperature ◽  
The United States ◽  
Department Of Energy ◽  
Synthesis Process ◽  
United States Department ◽  
Stoichiometric Ratio ◽  
Desorption Kinetic ◽  
Multi Phase

Hydrogen storage in its solid state is one of the main challenges for mobile and stationary applications. Some metal hydrides are potential candidates for energy storage. This is an experimental research, which represents a contribution to the study of Hydrogen storage in its solid state, by studying the influence of the proportional substitution of V for Zr in the stoichiometric ratio Zr2-XVXFe (X=0.0, 0.1 y 0.2). Results indicate that the synthesis process generates a multi-phase type microstructure, and the absorption and desorption kinetic is less than 5 minutes at room temperature, in line with the parameters established by the United States Department of Energy; however, it is clear that the desorption capacity decreases.

An Overview of the Direct Energy Conversion Proof of Principle Power Production Program

2004 ◽  
Author(s):  
D. King ◽  
G. Rochau ◽  
D. Oscar ◽  
C. Morrow ◽  
P. Tsvetkov ◽  
...  
Keyword(s):  
Energy Conversion ◽  
The United States ◽  
Department Of Energy ◽  
Future Research ◽  
United States Department ◽  
Commercial Development ◽  
Direct Energy Conversion ◽  
Project Description ◽  
Direct Energy ◽  
Proof Of Principle

The United States Department of Energy, Nuclear Energy Research Initiative (NERI) Direct Energy Conversion Proof of Principle (DECPOP) project has as its goal the development of a direct energy conversion process suitable for commercial development. We define direct energy conversion as any fission process that returns usable energy without an intermediate thermal process. A prior Direct Energy Conversion (DEC) project [1] has been completed and indicates that a viable direct energy device is possible if several technological issues can be overcome. The DECPOP program is focusing on two of the issues: charged particle steering and high voltage hold-off. This paper reports on the progress of the DECPOP project. Two prototype concepts are under development: a Fission Electric Cell using magnetic insulation and a Fission Fragment Magnetic Collimator using magnetic fields to direct fission fragments to collectors. Included in this paper are a short project description, an abbreviated summary of the work completed to date, a description of ongoing and future project activities, and a discussion of the potential for future research and development.

Investigation of the Down-Scaling Effects on the Low Swirl Burner and its Application to Microturbines

2018 ◽  
Author(s):  
Alex Frank ◽  
Peter Therkelsen ◽  
Miguel Sierra Aznar ◽  
Vi H. Rapp ◽  
Robert K. Cheng ◽  
...  
Keyword(s):  
Power Systems ◽  
Power Plants ◽  
Energy Savings ◽  
The United States ◽  
Primary Energy ◽  
Department Of Energy ◽  
Small Scale ◽  
United States Department ◽  
Scaling Effects ◽  
Swirl Burner

About 75% of the electric power generated by centralized power plants feeds the energy needs from the residential and commercial sectors. These power plants waste about 67% of primary energy as heat emitting 2 billion tons of CO2 per year in the process (∼ 38% of total US CO2 generated per year) [1]. A study conducted by the United States Department of Energy indicated that developing small-scale combined heat and power systems to serve the commercial and residential sectors could have a significant impact on both energy savings and CO2 emissions. However, systems of this scale historically suffer from low efficiencies for a variety of reasons. From a combustion perspective, at these small scales, few systems can achieve the balance between low emissions and high efficiencies due in part to the increasing sensitivity of the system to hydrodynamic and heat transfer effects. Addressing the hydrodynamic impact, the effects of downscaling on the flowfield evolution were studied on the low swirl burner (LSB) to understand if it could be adapted to systems at smaller scales. Utilizing particle image velocimetry (PIV), three different swirlers were studied ranging from 12 mm to 25.4 mm representing an output range of less than 1 kW to over 23 kW. Results have shown that the small-scale burners tested exhibited similar flowfield characteristics to their larger-scale counterparts in the non-reacting cases studied. Utilizing this data, as a proof of concept, a 14 mm diameter LSB with an output of 3.33 kW was developed for use in microturbine operating on a recuperated Brayton cycle. Emissions results from this burner proved the feasibility of the system at sufficiently lean mixtures. Furthermore, integration of the newly developed LSB into a can style combustor for a microturbine application was successfully completed and comfortably meet the stringent emissions targets. While the analysis of the non-reacting cases was successful, the reacting cases were less conclusive and further investigation is required to gain an understanding of the flowfield evolution which is the subject of future work.

Pressure Isotherms of Hydrogen Adsorption in Carbon Nanostructures

2001 ◽  
Vol 706 ◽  
Author(s):  
Xiaohong Chen ◽  
Urszula Dettlaff-Weglikowska ◽  
Miroslav Haluska ◽  
Martin Hulman ◽  
Siegmar Roth ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Activated Carbon ◽  
Hydrogen Storage ◽  
Carbon Nanostructures ◽  
Room Temperature ◽  
Storage Capacity ◽  
Hydrogen Adsorption ◽  
Single Wall Carbon Nanotubes ◽  
Hydrogen Storage Capacity ◽  
Carbon And Graphite

AbstractThe hydrogen adsorption capacity of various carbon nanostructures including single-wall carbon nanotubes, graphitic nanofibers, activated carbon, and graphite has been measured as a function of pressure and temperature. Our results show that at room temperature and a pressure of 80 bar the hydrogen storage capacity is less than 1 wt.% for all samples. Upon cooling, the capacity of hydrogen adsorption increases with decreasing temperature and the highest value was observed to be 2.9 wt. % at 50 bar and 77 K. The correlation between hydrogen storage capacity and specific surface area is discussed.

H2S and HS- Adsorption on a Charged Cu Surface in an Electrolyte: Effect of Ionic Strength

1997 ◽  
Vol 492 ◽  
Author(s):  
W. D. Wilson ◽  
C. M. Schaldach
Keyword(s):  
Ionic Strength ◽  
The United States ◽  
Binding Energies ◽  
Department Of Energy ◽  
Molecular Surface ◽  
Double Layers ◽  
Real Surface ◽  
United States Department ◽  
Surface Charges ◽  
Hartree Fock

ABSTRACTWe present a method for the calculation of the binding and rotational energies of neutral (H2S) and charged (HS-) molecules impinging upon a charged (Cu <100>) surface in the presence of an electrolyte. A molecular surface is constructed surrounding the H2S and HS- molecules forming boundary elements. A coupled Schrödinger-Poisson-Boltzmann iterative procedure treats the electronic structure of the molecules at the 6–31G**/MP2 level of theory and includes solvation effects through the single and double layers of charge induced by the electronic distribution. The molecule, together with its charged layers, forms a Molecular Single and Double Layer (MSDL), an object which then interacts with a Gouy-Chapman plane within the electrolyte. The additional induced charge at the molecular surface resulting from this electric field is obtained by solving a second set of boundary element equations. Repulsive interactions between the atoms of the molecule and those of the surface are obtained using a rigid-ion Hartree-Fock method. Binding energies of the molecule to the surface are determined as a function of the real surface charge imposed and also the ionic strength of the solution. It is found that surface charges can completely (180°) reorient these molecules and that the counterions in the solution can completely screen binding effects of even large surface charges.Work supported by the United States Department of Energy under contract #DE-AC04–94AL85000.

Application of SPSLIFE to Preliminary Design Evaluation and Life Assessment of CSGT Components

1995 ◽  
Vol 117 (3) ◽  
pp. 424-431
Author(s):  
A. Saith ◽  
P. F. Norton ◽  
V. M. Parthasarathy
Keyword(s):  
Gas Turbines ◽  
Computer Code ◽  
The United States ◽  
Department Of Energy ◽  
Life Assessment ◽  
Design Evaluation ◽  
United States Department ◽  
Preliminary Design ◽  
Detail Design ◽  
Stage 1

The Ceramic Stationary Gas Turbine (CSGT) Program has utilized the SPSLIFE computer code to evaluate the preliminary design of ceramic components. The CSGT program is being performed under the sponsorship of the United States Department of Energy, Office of Industrial Technology, to improve the performance of stationary gas turbines in cogeneration through the selective replacement of hot section components with ceramic parts. Preliminary design evaluation and life assessment results are presented here for the following components: (1) Stage 1 turbine blade, (2) Stage 1 turbine nozzle, and (3) combustor inner liner. From the results of the analysis, recommendations are made for improving the life and reliability of the components. All designs were developed in Phase I (preliminary design) of the CSGT program and will be optimized in Phase II (detail design) of the program.

The AGT101 Advanced Automotive Gas Turbine

1982 ◽  
Author(s):  
R. A. Rackley ◽  
J. R. Kidwell
Keyword(s):  
United States ◽  
Gas Turbine ◽  
The United States ◽  
Gas Turbine Engine ◽  
Development Project ◽  
Single Stage ◽  
Department Of Energy ◽  
Inlet Temperature ◽  
United States Department ◽  
Turbine Engine

The Garrett/Ford Advanced Gas Turbine Powertrain System Development Project, authorized under NASA Contract DEN3-167, is sponsored by and is part of the United States Department of Energy Gas Turbine Highway Vehicle System Program. Program effort is oriented at providing the United States automotive industry the technology base necessary to produce gas turbine powertrains competitive for automotive applications having: (1) reduced fuel consumption, (2) multi-fuel capability, and (3) low emissions. The AGT101 powertrain is a 74.6 kW (100 hp), regenerated single-shaft gas turbine engine operating at a maximum turbine inlet temperature of 1644 K (2500 °F), coupled to a split differential gearbox and Ford automatic overdrive production transmission. The gas turbine engine has a single-stage centrifugal compressor and a single-stage radial inflow turbine mounted on a common shaft. Maximum rotor speed is 10,472 rad/sec (100,000 rpm). All high-temperature components, including the turbine rotor, are ceramic. AGT101 powertrain development has been initiated, with testing completed on many aerothermodynamic components in dedicated test rigs and start of Mod I, Build 1 engine testing.

Application of Spslife to Preliminary Design Evaluation and Life Assessment of CSGT Components

1994 ◽  
Author(s):  
Arun Saith ◽  
Paul F. Norton ◽  
Vijay M. Parthasarathy
Keyword(s):  
Gas Turbines ◽  
Computer Code ◽  
The United States ◽  
Department Of Energy ◽  
Life Assessment ◽  
Design Evaluation ◽  
United States Department ◽  
Preliminary Design ◽  
Detail Design ◽  
Stage 1

The Ceramic Stationary Gas Turbine (CSGT) Program has utilized the SPSLIFE computer code to evaluate the preliminary design of ceramic components. The CSGT program is being performed under the sponsorship of the United States Department of Energy, Office of Industrial Technology, to improve the performance of stationary gas turbines in cogeneration through the selective replacement of hot section components with ceramic parts. Preliminary design evaluation and life assessment results are presented here for the following components: (1) Stage 1 Turbine Blade, (2) Stage 1 Turbine Nozzle, and (3) Combustor Inner Liner. From the results of the analysis, recommendations are made for improving the life and reliability of the components. All designs were developed in Phase I (preliminary design) of the CSGT program and will be optimized in Phase II (detail design) of the program.

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