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Electron Charged Graphite-based Hydrogen Storage Material

Description: The electron-charge effects have been demonstrated to enhance hydrogen storage capacity using materials which have inherent hydrogen storage capacities. A charge control agent (CCA) or a charge transfer agent (CTA) was applied to the hydrogen storage material to reduce internal discharge between particles in a Sievert volumetric test device. GTI has tested the device under (1) electrostatic charge mode; (2) ultra-capacitor mode; and (3) metal-hydride mode. GTI has also analyzed the charge distribution on storage materials. The charge control agent and charge transfer agent are needed to prevent internal charge leaks so that the hydrogen atoms can stay on the storage material. GTI has analyzed the hydrogen fueling tank structure, which contains an air or liquid heat exchange framework. The cooling structure is needed for hydrogen fueling/releasing. We found that the cooling structure could be used as electron-charged electrodes, which will exhibit a very uniform charge distribution (because the cooling system needs to remove heat uniformly). Therefore, the electron-charge concept does not have any burden of cost and weight for the hydrogen storage tank system. The energy consumption for the electron-charge enhancement method is quite low or omitted for electrostatic mode and ultra-capacitor mode in comparison of other hydrogen storage methods; however, it could be high for the battery mode.
Date: March 14, 2012
Creator: 0812, Dr. Chinbay Q. Fan R&D Manager Office of Technology and Innovations Phone: 847 768
Partner: UNT Libraries Government Documents Department

Markov Model of Accident Progression at Fukushima Daiichi

Description: On March 11, 2011, a magnitude 9.0 earthquake followed by a tsunami caused loss of offsite power and disabled the emergency diesel generators, leading to a prolonged station blackout at the Fukushima Daiichi site. After successful reactor trip for all operating reactors, the inability to remove decay heat over an extended period led to boil-off of the water inventory and fuel uncovery in Units 1-3. A significant amount of metal-water reaction occurred, as evidenced by the quantities of hydrogen generated that led to hydrogen explosions in the auxiliary buildings of the Units 1 & 3, and in the de-fuelled Unit 4. Although it was assumed that extensive fuel damage, including fuel melting, slumping, and relocation was likely to have occurred in the core of the affected reactors, the status of the fuel, vessel, and drywell was uncertain. To understand the possible evolution of the accident conditions at Fukushima Daiichi, a Markov model of the likely state of one of the reactors was constructed and executed under different assumptions regarding system performance and reliability. The Markov approach was selected for several reasons: It is a probabilistic model that provides flexibility in scenario construction and incorporates time dependence of different model states. It also readily allows for sensitivity and uncertainty analyses of different failure and repair rates of cooling systems. While the analysis was motivated by a need to gain insight on the course of events for the damaged units at Fukushima Daiichi, the work reported here provides a more general analytical basis for studying and evaluating severe accident evolution over extended periods of time. This work was performed at the request of the U.S. Department of Energy to explore 'what-if' scenarios in the immediate aftermath of the accidents.
Date: November 11, 2012
Creator: A., Cuadra; R., Bari; Cheng, L-Y; Ginsberg, T.; Lehner, J.; Martinez-Guridi, G. et al.
Partner: UNT Libraries Government Documents Department

Characterization of Environmental Stability of Pulsed Laser Deposited Oxide Ceramic Coatings

Description: A systematic investigation of candidate hydrogen permeation materials applied to a substrate using Pulsed Laser Deposition has been performed. The investigation focused on application of leading permeation-resistant materials types (oxide, carbides, and metals) on a stainless steel substrate. and evaluation of the stability of the applied coatings. Type 304L stainless steel substrates were coated with aluminum oxide, chromium oxide, and aluminum. Characterization of the coating-substrate system adhesion was performed using scratch adhesion testing and microindentation. Coating stability and environmental susceptibility were evaluated for two conditions-air at 350 degrees Celsius and Ar-H2 at 350 degrees Celsius for up to 100 hours. Results from this study have shown the pulsed laser deposition process to be an extremely versatile technology that is capable of producing a sound coating/substrate system for a wide variety of coating materials.
Date: March 2, 2004
Creator: ADAMS, THADM
Partner: UNT Libraries Government Documents Department

Caustic Precipitation of Plutonium and Uranium with Gadolinium as a Neutron Poison

Description: The caustic precipitation of plutonium (Pu) and uranium (U) from Pu and U containing waste solutions has been investigated to determine whether gadolinium (Gd) could be used as a neutron poison for precipitation with greater than a fissile mass containing both Pu and enriched U. Precipitation experiments were performed using both actual samples and simulant solutions with a range of 2.6-5.16 g/L U and 0-4.3 to 1 U to Pu. Analyses were performed on solutions at intermediate pH to determine the partitioning of elements for accident scenarios. When both Pu and U were present in the solution, precipitation began at pH 4.5 and by pH 7, 99 percent of Pu and U had precipitated. When complete neutralization was achieved at pH greater than 14 with 1.2 M excess OH-, greater than 99 percent of Pu, U, and Gd had precipitated. At pH greater than 14, the particles sizes were larger and the distribution was a single mode. The ratio of hydrogen to fissile atoms in the precipitate was determined after both settling and centrifuging and indicates that sufficient water was associated with the precipitates to provide the needed neutron moderation for Gd to prevent a criticality in solutions containing up to 4.3 to 1 U to Pu and up to 5.16 g/L U.
Date: April 14, 2005
Creator: ANN, VISSER
Partner: UNT Libraries Government Documents Department

Hydrogen Storage Properties of Magnesium Base Nanostructured Composite Materials

Description: In this work, nanostructured composite materials have been synthesized using the mechanical alloying process. The new materials produced have been investigated by X-ray diffraction (XRD), transition electron microscope (TEM), scanning electron microscope (SEM) and electron energy dispersion spectrum (EDS) for their phase compositions, crystal structure, grain size, particle morphology and the distribution of catalyst element. Hydrogen storage capacities and the hydriding-dehydriding kinetics of the new materials have been measured at different temperatures using a Sieverts apparatus. It is observed that mechanical alloying accelerates the hydrogenation kinetics of the magnesium based materials at low temperature, but a high temperature must be provided to release the absorbed hydrogen from the hydrided magnesium based materials. It is believed that the dehydriding temperature is largely controlled by the thermodynamic configuration of magnesium hydride. Doping Mg-Ni nano/amorphous composite materials with lanthanum reduces the hydriding and dehydriding temperature. Although the stability of MgH2 can not be easily reduced by ball milling alone, the results suggest the thermodynamic properties of Mg-Ni nano/amorphous composite materials can be alternated by additives such as La or other effective elements. Further investigation toward understanding the mechanism of additives will be rewarded.
Date: April 30, 2004
Creator: AU, M
Partner: UNT Libraries Government Documents Department

Hydrogen Storage Properties of the Tetrahydrofuran Treated Magnesium

Description: The electronic structure, crystalline feature and morphology of the tetrahydrofuran (THF) treated magnesium, along with its hydriding and dehydriding properties have been investigated. The THF treated magnesium absorbs 6.3 wt per cent hydrogen at 723K and 3.5 MPa. After hydrogenation, in addition to the expected MgH2, a new less-stable hydride phase appears at 673K, but not at a lower temperature. Desorption produces 5.5 wt per cent hydrogen at 723K against a back pressure of 1.3 Pa after 20 cycles of hydriding-dehydriding. The THF treatment improves the kinetics of hydrogen absorption and desorption significantly. From 723K to 623K, the THF treated Mg demonstrates acceptable reaction rates. XPS studies show that tetrahydrofuran treatment causes the electronic energy state of the magnesium surface atoms to change, but the XRD studies show the crystal structure remains unchanged. Metallographic observation of the bulk hydrides of THF treated magnesium reveal they are poly-crystalline wi th the wide-spreading slip bands and twins within the crystals, indicating the phase transformation upon hydriding causes serious stress and distortion. It appears this microstructural deformation explains the much higher energy requirements (higher pressure and temperature) for magnesium hydrogenation than the simple lattice expansion that accompany hydrogen uptake for LaNi5 and FeTi.
Date: May 25, 2004
Creator: AU, MING
Partner: UNT Libraries Government Documents Department

Fermi LAT Observation of Diffuse Gamma-Rays Produced through Interactions Between Local Interstellar Matter and High Energy Cosmic Rays

Description: Observations by the Large Area Telescope (LAT) on the Fermi mission of diffuse {gamma}-rays in a mid-latitude region in the third quadrant (Galactic longitude l from 200{sup o} to 260{sup o} and latitude |b| from 22{sup o} to 60{sup o}) are reported. The region contains no known large molecular cloud and most of the atomic hydrogen is within 1 kpc of the solar system. The contributions of {gamma}-ray point sources and inverse Compton scattering are estimated and subtracted. The residual {gamma}-ray intensity exhibits a linear correlation with the atomic gas column density in energy from 100 MeV to 10 GeV. The measured integrated {gamma}-ray emissivity is (1.63 {+-} 0.05) x 10{sup -26} photons s{sup -1}sr{sup -1} H-atom{sup -1} and (0.66 {+-} 0.02) x 10{sup -26} photons s{sup -1}sr{sup -1} H-atom{sup -1} above 100 MeV and above 300 MeV, respectively, with an additional systematic error of {approx}10%. The differential emissivity from 100 MeV to 10 GeV agrees with calculations based on cosmic ray spectra consistent with those directly measured, at the 10% level. The results obtained indicate that cosmic ray nuclei spectra within 1 kpc from the solar system in regions studied are close to the local interstellar spectra inferred from direct measurements at the Earth within {approx}10%.
Date: March 30, 2012
Creator: Abdo, A.A.; /Naval Research Lab, Wash., D.C. /Federal City Coll.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. et al.
Partner: UNT Libraries Government Documents Department

THE IMPACT OF TRACE ADDITIVES ON THE APPARENT SOLUBILITY OF HYDROGEN IN HEAVY OIL AND RELATED FEEDSTOCKS AT LOW AND HIGH TEMPERATURES

Description: A systematic investigation was conducted to provide an accurate determination of hydrogen solubility in liquid media in temperatures in the range of 25-250 C and pressures in the range of 0.5-8 MPa. Results were obtained by an indirect gas solubility measurement method. The method was intended for use with high-resolution camera. The hydrogen solubility measurements were indirect and were based on pressure changes at constant temperature and measured volumes. Since the volume of the view cell was fixed the volume available for the vapor phase could be determined by measuring the location of the liquid-vapor interface. The interface was located to within the height of one pixel using high-resolution camera, which added {+-} 0.4 ml to the uncertainty of the vapor volume. Liquid-liquid interface locations were measured with equal precision. The accuracy of the method was illustrated through hydrogen solubility measurements in hexadecane and tetralin, which were in close agreement with the values available in the literature. Hydrogen solubilities in Athabasca bitumen vacuum bottoms (ABVB) were reported over a broad range of temperatures (80-250 C) and pressures (0.5-8 MPa).
Date: September 1, 2002
Creator: Abedi, Jalal
Partner: UNT Libraries Government Documents Department

The H II Region of a Primordial Star

Description: The concordance model of cosmology and structure formation predicts the formation of isolated very massive stars at high redshifts in dark matter dominated halos of 10{sup 5} to 10{sup 6} Msun. These stars photo-ionize their host primordial molecular clouds, expelling all the baryons from their halos. When the stars die, a relic H II region is formed within which large amounts of molecular hydrogen form which will allow the gas to cool efficiently when gravity assembles it into larger dark matter halos. The filaments surrounding the first star hosting halo are largely shielded and provide the pathway for gas to stream into the halo when the star has died. We present the first fully three dimensional cosmological radiation hydrodynamical simulations that follow all these effects. A novel adaptive ray casting technique incorporates the time dependent radiative transfer around point sources. This approach is fast enough so that radiation transport, kinetic rate equations, and hydrodynamics are solved self-consistently. It retains the time derivative of the transfer equation and is explicitly photon conserving. This method is integrated with the cosmological adaptive mesh refinement code enzo, and runs on distributed and shared memory parallel architectures. Where applicable the three dimensional calculation not only confirm expectations from earlier one dimensional results but also illustrate the multi-fold hydrodynamic complexities of H II regions. In the absence of stellar winds the circumstellar environments of the first supernovae and putative early gamma-ray bursts will be of low density {approx}1 cm{sup -3}. Albeit marginally resolved, ionization front instabilities lead to cometary and elephant trunk like small scale structures reminiscent of nearby star forming regions.
Date: June 7, 2006
Creator: Abel, Tom; Wise, John H.; /KIPAC, Menlo Park; Bryan, Greg L. & /Columbia U., Astron. Astrophys.
Partner: UNT Libraries Government Documents Department

Development of an electrochemical hydrogen separator

Description: The electrochemical hydrogen separator (EHS), under development at ERC, has several attractive features: The operating temperature (150[degree]C--200[degree]C) is higher than those associated with the currently available devices and is compatible with the low temperature shift reactors. The EHS can operate at atmospheric as well as elevated pressures and the product H[sub 2] is available at the feed stream pressure. High hydrogen recovery factor: 90% H[sub 2] recovery from feed streams containing less than 10% hydrogen is feasible. High hydrogen purity: The product H[sub 2] purity is >99% (dry basis) and is virtually independent of H[sub 2] concentration in the feed gas. The process is continuous. Low energy cost: Depending upon the operating conditions, the energy requirement varies between 2 to 6 kWh/1000 SCF of recovered hydrogen.
Date: January 1, 1992
Creator: Abens, S.; Fruchtman, J. & Kush, A.
Partner: UNT Libraries Government Documents Department

Development of an electrochemical hydrogen separator

Description: The EHS is an electrochemical hydrogen separator based on the uniquely reversible nature of hydrogen oxidation-reduction reactions in electrochemical systems. The principle and the hardware concept are shown in Figure 1. Hydrogen from the mixed gas stream is oxidized to H{sup +} ions, transported through a cation transport electrolyte membrane (matrix) under an applied electric field and discharged in a pure hydrogen state on the cathode. The cation transfer electrolyte membrane provides a barrier between the feed and product gases. The EHS design is an offshoot of phosphoric acid fuel cell development. Although any proton transfer electrolyte can be used, the phosphoric acid based system offers a unique advantage because its operating temperature of {approximately}200{degree}C makes it tolerant to trace CO and also closely matches the water-shift reactor exit gas temperature ({approximately}250{degree}C). Hydrogen-containing streams in coal gasification systems have large carbon monoxide contents. For efficient hydrogen recovery, most of the CO must be converted to hydrogen by the low temperature water-shift reaction (Figure 2). Advanced coal gasification and gas separation technologies offer an important pathway to the clean utilization of coal resources.
Date: September 1, 1993
Creator: Abens, S.; Fruchtman, J. & Kush, A.
Partner: UNT Libraries Government Documents Department

Development of an electrochemical hydrogen separator

Description: The electrochemical hydrogen separator (EHS), under development at ERC, has several attractive features: The operating temperature (150{degree}C--200{degree}C) is higher than those associated with the currently available devices and is compatible with the low temperature shift reactors. The EHS can operate at atmospheric as well as elevated pressures and the product H{sub 2} is available at the feed stream pressure. High hydrogen recovery factor: 90% H{sub 2} recovery from feed streams containing less than 10% hydrogen is feasible. High hydrogen purity: The product H{sub 2} purity is >99% (dry basis) and is virtually independent of H{sub 2} concentration in the feed gas. The process is continuous. Low energy cost: Depending upon the operating conditions, the energy requirement varies between 2 to 6 kWh/1000 SCF of recovered hydrogen.
Date: November 1, 1992
Creator: Abens, S.; Fruchtman, J. & Kush, A.
Partner: UNT Libraries Government Documents Department

Cornell Fuel Cell Institute: Materials Discovery to Enable Fuel Cell Technologies

Description: The discovery and understanding of new, improved materials to advance fuel cell technology are the objectives of the Cornell Fuel Cell Institute (CFCI) research program. CFCI was initially formed in 2003. This report highlights the accomplishments from 2006-2009. Many of the grand challenges in energy science and technology are based on the need for materials with greatly improved or even revolutionary properties and performance. This is certainly true for fuel cells, which have the promise of being highly efficient in the conversion of chemical energy to electrical energy. Fuel cells offer the possibility of efficiencies perhaps up to 90 % based on the free energy of reaction. Here, the challenges are clearly in the materials used to construct the heart of the fuel cell: the membrane electrode assembly (MEA). The MEA consists of two electrodes separated by an ionically conducting membrane. Each electrode is a nanocomposite of electronically conducting catalyst support, ionic conductor and open porosity, that together form three percolation networks that must connect to each catalyst nanoparticle; otherwise the catalyst is inactive. This report highlights the findings of the three years completing the CFCI funding, and incudes developments in materials for electrocatalyts, catalyst supports, materials with structured and functional porosity for electrodes, and novel electrolyte membranes. The report also discusses developments at understanding electrocatalytic mechanisms, especially on novel catalyst surfaces, plus in situ characterization techniques and contributions from theory. Much of the research of the CFCI continues within the Energy Materials Center at Cornell (emc2), a DOE funded, Office of Science Energy Frontier Research Center (EFRC).
Date: June 29, 2012
Creator: Abruna, H.D. & DiSalvo, Francis J.
Partner: UNT Libraries Government Documents Department

Vehicular Storage of Hydrogen in Insulated Pressure Vessels

Description: This paper describes the development of an alternative technology for storing hydrogen fuel onboard automobiles. Insulated pressure vessels are cryogenic-capable pressure vessels that can accept cryogenic liquid fuel, cryogenic compressed gas or compressed gas at ambient temperature. Insulated pressure vessels offer advantages over conventional H{sub 2} storage approaches. Insulated pressure vessels are more compact and require less carbon fiber than GH{sub 2} vessels. They have lower evaporative losses than LH{sub 2} tanks, and are much lighter than metal hydrides. After outlining the advantages of hydrogen fuel and insulated pressure vessels, the paper describes the experimental and analytical work conducted to verify that insulated pressure vessels can be used safely for vehicular H{sub 2} storage. The paper describes tests that have been conducted to evaluate the safety of insulated pressure vessels. Insulated pressure vessels have successfully completed a series of DOT, ISO and SAE certification tests. A draft procedure for insulated pressure vessel certification has been generated to assist in a future commercialization of this technology. An insulated pressure vessel has been installed in a hydrogen fueled truck and it is currently being subjected to extensive testing.
Date: January 3, 2005
Creator: Aceves, S M; Berry, G D; Martinez-Frias, J & Espinosa-Loza, F
Partner: UNT Libraries Government Documents Department

Evaluation of insulated pressure vessels for cryogenic hydrogen storage

Description: This paper presents an analytical and experimental evaluation of the applicability of insulated pressure vessels for hydrogen-fueled light-duty vehicles. Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH?) or ambient-temperature compressed hydrogen (CH2). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The purpose of this work is to verify that commercially available aluminum-lined, fiber- wrapped vessels can be used for cryogenic hydrogen storage. The paper reports on previous and ongoing tests and analyses that have the purpose of improving the system design and assure its safety.
Date: March 1, 1999
Creator: Aceves, S M; Garcia-Villazana, O & Martinez-Frias, J
Partner: UNT Libraries Government Documents Department

Certification Testing and Demonstration of Insulated Pressure Vessels for Vehicular Hydrogen Storage

Description: Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen or ambient-temperature compressed hydrogen. This flexibility results in multiple advantages with respect to compressed hydrogen tanks or low-pressure liquid hydrogen tanks. Our work is directed at verifying that commercially available aluminum-lined, fiber-wrapped pressure vessels can be safely used to store liquid hydrogen. A series of tests have been conducted, and the results indicate that no significant vessel damage has resulted from cryogenic operation. Future activities include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for certification of insulated pressure vessels.
Date: May 22, 2002
Creator: Aceves, S M; Martinez-Frias, J & Espinosa-Loza, F
Partner: UNT Libraries Government Documents Department

Performance Evaluation Tests of Insulated Pressure Vessels for Vehicular Hydrogen Storage

Description: Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen or ambient-temperature compressed hydrogen. This flexibility results in multiple advantages with respect to compressed hydrogen tanks or low-pressure liquid hydrogen tanks. Our work is directed at verifying that commercially available aluminum-lined, fiber-wrapped pressure vessels can be safely used to store liquid hydrogen. A series of tests have been conducted, and the results indicate that no significant vessel damage has resulted from cryogenic operation. Future activities include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for certification of insulated pressure vessels.
Date: March 1, 2002
Creator: Aceves, S M; Martinez-Frias, J & Espinoza-Loza, F
Partner: UNT Libraries Government Documents Department

Certification Testing and Demonstration of Insulated Pressure Vessels for Vehicular Hydrogen and Natural Gas Storage

Description: We are working on developing an alternative technology for storage of hydrogen or natural gas on light-duty vehicles. This technology has been titled insulated pressure vessels. Insulated pressure vessels are cryogenic-capable pressure vessels that can accept either liquid fuel or ambient-temperature compressed fuel. Insulated pressure vessels offer the advantages of cryogenic liquid fuel tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for fuel liquefaction and reduced evaporative losses). The work described in this paper is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen or LNG. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Future activities include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for obtaining insulated pressure vessel certification.
Date: May 22, 2002
Creator: Aceves, S M; Martinez-Frias, J; Espinosa-Loza, F; Schaffer, R & Clapper, W
Partner: UNT Libraries Government Documents Department

Insulated Pressure Vessels for Vehicular Hydrogen Storage: Analysis and Performance Evaluation

Description: Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH{sub 2}) or ambient-temperature compressed hydrogen (CH{sub 2}). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Required future tests are described that will prove that no technical barriers exist to the safe use of aluminum-fiber vessels at cryogenic temperatures. Future activities also include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for obtaining certification for insulated pressure vessels.
Date: June 26, 2001
Creator: Aceves, S M; Martinez-Frias, J; Garcia-Villazana, O & Espinosa-Loza, F
Partner: UNT Libraries Government Documents Department

Performance and Certification Testing of Insulated Pressure Vessels for Vehicular Hydrogen Storage

Description: Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH2) or ambient-temperature compressed hydrogen (CH2). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Required future tests are described that will prove that no technical barriers exist to the safe use of aluminum-fiber vessels at cryogenic temperatures. Future activities also include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for obtaining certification for insulated pressure vessels.
Date: June 3, 2001
Creator: Aceves, S M; Martinez-Frias, J; Garcia-Villazana, O & Espinosa-Loza, F
Partner: UNT Libraries Government Documents Department

A Comprehensive Study of Surface Chemistry for Application to Engine NOx Aftertreatment

Description: This work focuses on developing a scientific understanding of the processes associated with NO{sub x} trap operation. NO{sub x} traps are the most advanced technology for achieving future emissions standards with diesel engines. Successful development of NO{sub x} traps will allow widespread use of diesel engines in light-duty vehicles, reducing oil imports by as much as 60%. Diesel engines have a high efficiency and low maintenance that makes them the ideal choice for transportation applications. Use of diesel engines in all light-duty vehicles would reduce oil consumption in the USA by 30% and oil imports by 60%, considerably improving our energy security. For heavy trucks, there is no viable alternative to diesel engines. Only diesel engines can provide the necessary high efficiency and long life. These benefits are offset by high emission of pollutants. Diesel engines have high emissions of NO{sub x} and particulate matter. Over the last 20 years, EPA has been reducing allowable emissions from diesel engines, and NO{sub x} emissions are scheduled to be cut by a factor of 10 over the next 7 years. The target NO{sub x} emissions for year 2010 is 0.20 g/hp-hr. This value is well below 1 g/hp-hr, which has been identified by one of the authors (Pitz [1]) as the minimum possible NO{sub x} emissions that can be obtained in a diesel engine with satisfactory combustion and without exhaust aftertreatment. An 80% efficient aftertreatment system is therefore necessary for achieving the 2010 NO{sub x} emissions regulation. Achieving this level of diesel aftertreatment efficiency is a daunting task, and one that will require a strong research effort. Manufacturing diesel after treatment systems with 80% efficiency for model year 2010 is an extremely difficult task. Our advanced analysis tools (computational chemistry linked with fluid mechanics and heat transfer) can be used to analyze ...
Date: February 19, 2004
Creator: Aceves, S M; Piggot, T; Pitz, W; Mundy, C; Kuo, W & Havstad, M
Partner: UNT Libraries Government Documents Department

Analysis of experimental hydrogen engine data and hydrogen vehicle performance and emissions simulation

Description: This paper reports the engine and vehicle simulation and analysis done at Lawrence Livermore (LLNL) as a part of a joint optimized hydrogen engine development effort. Project participants are: Sandia National Laboratory, California (SNLC), responsible for experimental evaluation; Los Alamos National Laboratory (LANL), responsible for detailed fluid mechanics engine evaluations, and the University of Miami, responsible for engine friction reduction. Fuel cells are considered as the ideal power source for future vehicles, due to their high efficiency and low emissions. However, extensive use of fuel cells in light-duty vehicles is likely to be years away, due to their high manufacturing cost. Hydrogen-fueled, spark-ignited, homogeneous-charge engines offer a near-term alternative to fuel cells. Hydrogen in a spark-ignited engine can be burned at very low equivalence ratios, so that NO{sub x} emissions can be reduced to less than 10 ppm without catalyst. HC and CO emissions may result from oxidation of engine oil, but by proper design are negligible (a few ppm). Lean operation also results in increased indicated efficiency due to the thermodynamic properties of the gaseous mixture contained in the cylinder. The high effective octane number of hydrogen allows the use of a high compression ratio, further increasing engine efficiency.
Date: September 1996
Creator: Aceves, S. M.
Partner: UNT Libraries Government Documents Department