The Experts below are selected from a list of 87 Experts worldwide ranked by ideXlab platform
Peter Wasserscheid - One of the best experts on this subject based on the ideXlab platform.
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Liquid organic Hydrogen carriers (LOHCs): Toward a Hydrogen-free Hydrogen economy
Accounts of Chemical Research, 2017Co-Authors: Patrick Preuster, Christian Papp, Peter WasserscheidAbstract:ConspectusThe need to drastically reduce CO2 emissions will lead to the transformation of our current, carbon-based energy system to a more sustainable, renewable-based one. In this process, Hydrogen will gain increasing importance as secondary energy vector. Energy storage requirements on the TWh scale (to bridge extended times of low wind and sun harvest) and global logistics of renewable energy equivalents will create additional driving forces toward a future Hydrogen economy. However, the nature of Hydrogen requires dedicated infrastructures, and this has prevented so far the introduction of Elemental Hydrogen into the energy sector to a large extent. Recent scientific and technological progress in handling Hydrogen in chemically bound form as liquid organic Hydrogen carrier (LOHC) supports the technological vision that a future Hydrogen economy may work without handling large amounts of Elemental Hydrogen. LOHC systems are composed of pairs of Hydrogen-lean and Hydrogen-rich organic compounds that st...
Nilufer Kucukdeveci - One of the best experts on this subject based on the ideXlab platform.
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development of the high performance magnesium based Hydrogen storage alloy
International Journal of Hydrogen Energy, 2012Co-Authors: Mustafa Anik, Fatma Karanfil, Nilufer KucukdeveciAbstract:Abstract Series of MgNi type alloys with Ti, Al, Zr, Pd and Co additive elements were synthesized by mechanical alloying and their electrochemical Hydrogen storage characteristics were investigated. Systematical alloy designing indicated that Mg 0.80 Ti 0.15 Al 0.05 Zr 0.05 Ni 0.95 alloy has the best electrode performance. The atomic fractions in this alloy were believed to be optimum to get the reasonable amount of Hydrogen storage with the improved cyclic stability. Titanium was estimated to enter into Mg(OH) 2 layer during the discharging process and make this barrier layer more penetrable by Elemental Hydrogen. Al and/or Al-oxides were predicted to dissolve selectively throughout the barrier hydroxide layer and thus reduce the stability of this layer. The main contribution of Zr was estimated to arise from its large atomic size that Zr atoms can create extra sites for the Elemental Hydrogen in the alloy structure. As the alloy charge transfer resistances decreased, the alloy retention rates increased. Improvement in the alloy capacity retaining rate was also closely related with the Hydrogen diffusion coefficients in the alloy.
Wolfgang Arlt - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic evaluation of potential organic Hydrogen carriers
Energy technology, 2013Co-Authors: Karsten Muller, Johannes Volkl, Wolfgang ArltAbstract:Hydrogen storage is a technology of major interest for the energy systems of the future. Fluctuations in power production by renewable energy technologies necessitate the storage of energy. Because most storage technologies suffer from low storage densities and capacities as well as high costs, chemical storage by using Hydrogen is meaningful. [1, 2] Hydrogen is currently produced mainly by conversion of fossil fuels (steam reforming). In the future the production of Hydrogen through the electrolysis of water, using electricity from wind or solar power, is likely to contribute substantially to the total Hydrogen production volume. Furthermore, Hydrogen could be produced via other renewable sources of energy, such as biomass [3] or photocatalytic water splitting. [4, 5] A number of issues have to be addressed in order to store Hydrogen. For Elemental Hydrogen high pressures or very low temperatures must be applied. This causes additional energy demands and consequently a drop in overall efficiency. The energy demand of liquefaction consumes about 30 % of the lower heating value of Hydrogen. The energy demand of compressing Hydrogen is lower (about 12 % for 350 bar; about 15 % for 700 bar) and the overall efficiency for compressed Hydrogen is thus higher. [6] Furthermore, for liquid Hydrogen significant amounts are lost by evaporation during storage. There again, the storage densities of compressed Hydrogen are lower than for liquid Hydrogen. To overcome the limitations associated with Elemental Hydrogen, its conversion into another form is advisable. Three basic types of conversion exist:
Dugstad Arne - One of the best experts on this subject based on the ideXlab platform.
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Corrosion of armor wire steel in the annulus of flexible pipes at near neutral pH
2019Co-Authors: Campos Tatiane, Seiersten Marion, Gomes, José Antônio, Palencsar Simona, Dugstad ArneAbstract:Stress corrosion cracking (SCC) of carbon steel may occur at near neutral pH in deoxygenated solutions with high bicarbonate concentration. Similar conditions are encountered in the annular space of flexible pipes when it is filled with CO2 containing condensed water or seawater. The CO2 diffuses from the bore into the annulus through the polymer sheets. Corrosion of the armor wires in contact with the water will result in high levels of Fe2+ and bicarbonate (HCO3-). Several studies have indicated that SCC may occur in solutions with high HCO3- concentration by production of Elemental Hydrogen during the corrosion reaction. The objective of the present study was to investigate if such conditions can persist for sufficiently long time in the annulus of flexible pipes to induce SCC of armor wire steel. It implies that the nucleation and growth of siderite (FeCO3) is so slow that the solution remains supersaturated for days to weeks. The results show that it is possible. At temperature lower than 40 °C and CO2 partial pressure of 10-5 kPa the saturation ratios (SR) of siderite can remain much higher than 1 and maintain a near-neutral pH for several hundred hours. However, the corrosion rate of armor wire steel at these conditions is low. Siderite precipitates at the steel surface and the cathodic reaction rate becomes diffusion controlled. Paper reproduced with permission from CORROSION/2019 Annual Conference and Exhibition. www.nace.orgpublishedVersio
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Corrosion of armor wire steel in the annulus of flexible pipes at near neutral pH
2019Co-Authors: Campos Tatiane, Seiersten Marion, Gomes, José Antônio, Palencsar Simona, Dugstad ArneAbstract:Stress corrosion cracking (SCC) of carbon steel may occur at near neutral pH in deoxygenated solutions with high bicarbonate concentration. Similar conditions are encountered in the annular space of flexible pipes when it is filled with CO2 containing condensed water or seawater. The CO2 diffuses from the bore into the annulus through the polymer sheets. Corrosion of the armor wires in contact with the water will result in high levels of Fe2+ and bicarbonate (HCO3-). Several studies have indicated that SCC may occur in solutions with high HCO3- concentration by production of Elemental Hydrogen during the corrosion reaction. The objective of the present study was to investigate if such conditions can persist for sufficiently long time in the annulus of flexible pipes to induce SCC of armor wire steel. It implies that the nucleation and growth of siderite (FeCO3) is so slow that the solution remains supersaturated for days to weeks. The results show that it is possible. At temperature lower than 40 °C and CO2 partial pressure of 10-5 kPa the saturation ratios (SR) of siderite can remain much higher than 1 and maintain a near-neutral pH for several hundred hours. However, the corrosion rate of armor wire steel at these conditions is low. Siderite precipitates at the steel surface and the cathodic reaction rate becomes diffusion controlled. Paper reproduced with permission from CORROSION/2019 Annual Conference and Exhibition. www.nace.or
Patrick Preuster - One of the best experts on this subject based on the ideXlab platform.
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Liquid organic Hydrogen carriers (LOHCs): Toward a Hydrogen-free Hydrogen economy
Accounts of Chemical Research, 2017Co-Authors: Patrick Preuster, Christian Papp, Peter WasserscheidAbstract:ConspectusThe need to drastically reduce CO2 emissions will lead to the transformation of our current, carbon-based energy system to a more sustainable, renewable-based one. In this process, Hydrogen will gain increasing importance as secondary energy vector. Energy storage requirements on the TWh scale (to bridge extended times of low wind and sun harvest) and global logistics of renewable energy equivalents will create additional driving forces toward a future Hydrogen economy. However, the nature of Hydrogen requires dedicated infrastructures, and this has prevented so far the introduction of Elemental Hydrogen into the energy sector to a large extent. Recent scientific and technological progress in handling Hydrogen in chemically bound form as liquid organic Hydrogen carrier (LOHC) supports the technological vision that a future Hydrogen economy may work without handling large amounts of Elemental Hydrogen. LOHC systems are composed of pairs of Hydrogen-lean and Hydrogen-rich organic compounds that st...