The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Thomas Turek - One of the best experts on this subject based on the ideXlab platform.
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Alkaline Water Electrolysis Powered by Renewable Energy: A Review
Processes, 2020Co-Authors: Jörn Brauns, Thomas TurekAbstract:Alkaline Water electrolysis is a key technology for large-scale hydrogen production powered by renewable energy. As conventional electrolyzers are designed for operation at fixed process conditions, the implementation of fluctuating and highly intermittent renewable energy is challenging. This contribution shows the recent state of system descriptions for Alkaline Water electrolysis and renewable energies, such as solar and wind power. Each component of a hydrogen energy system needs to be optimized to increase the operation time and system efficiency. Only in this way can hydrogen produced by electrolysis processes be competitive with the conventional path based on fossil energy sources. Conventional Alkaline Water electrolyzers show a limited part-load range due to an increased gas impurity at low power availability. As explosive mixtures of hydrogen and oxygen must be prevented, a safety shutdown is performed when reaching specific gas contamination. Furthermore, the cell voltage should be optimized to maintain a high efficiency. While photovoltaic panels can be directly coupled to Alkaline Water electrolyzers, wind turbines require suitable converters with additional losses. By combining Alkaline Water electrolysis with hydrogen storage tanks and fuel cells, power grid stabilization can be performed. As a consequence, the conventional spinning reserve can be reduced, which additionally lowers the carbon dioxide emissions.
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process modelling of an Alkaline Water electrolyzer
International Journal of Hydrogen Energy, 2017Co-Authors: P Haug, Bjarne Kreitz, Thomas TurekAbstract:Abstract In this paper a model for the prediction of the product gas purity in Alkaline Water electrolysis is proposed. For the estimation of the exhaust gas compositions the operating conditions, such as current density, electrolyte flow rate, concentration and temperature as well as process management possibilities are considered. The development of the model relies on a classical process engineering approach and depicts the electrolysis cell through coupled continuously stirred-tank reactors. Furthermore, the mass transport phenomena between the phases are considered through the application of Reynolds and Sherwood correlations. Finally, the validation of the model is performed through experiments, which are carried out in a lab-scale electrolyzer with a 150 cm 2 zero-gap cell and KOH electrolyte at atmospheric pressure. This investigation reveals that gas purity in Alkaline Water electrolysis is mainly affected by mixing the anodic and cathodic electrolyte cycles, which transport dissolved electrolysis products into the opposite half cell compartments. However, this transport mechanism can be significantly reduced by adjustment of the operating conditions of the electrolyzer.
Peter M. Kopittke - One of the best experts on this subject based on the ideXlab platform.
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Overhead-irrigation with saline and Alkaline Water: deleterious effects on foliage of Rhodes grass and leucaena
Agricultural Water Management, 2016Co-Authors: Federico D.f. Cicchelli, Neal W. Menzies, J. Bernhard Wehr, Scott A. Dalzell, Peter M. KopittkeAbstract:Abstract Saline and Alkaline Water represents a potentially valuable resource provided its irrigation does not decrease plant growth. Although the adverse effects of salts within the rooting environment are well-studied, comparatively little is known regarding the direct effects of overhead-irrigation of saline and Alkaline Water on plant foliage. The present study examined the potential deleterious effects of saline (electrical conductivity, EC, ≤15 dS m−1) and Alkaline (≤2000 mg L−1, CaCO3 equivalent) Water on foliage of Rhodes grass (Chloris gayana cv. Reclaimer) and leucaena (Leucaena leucocephala ssp. glabrata cv. Tarramba) under a range of growing-conditions. Foliage of leucaena was sensitive, with necrosis and chlorosis evident for saline Water at an EC ≥3 dS m−1 and Alkaline Water containing ≥500 mg L−1 (CaCO3 equivalent). For leucaena, this damage to the foliage reduced relative shoot fresh mass and chlorophyll fluorescence for saline-treatments, but alkalinity did not reduce relative shoot fresh mass or chlorophyll fluorescence in any treatment. In contrast to leucaena, relative shoot fresh mass of Rhodes grass was not reduced by foliar-applied salinity in any treatment (nor did alkalinity reduce growth of Rhodes grass). It was noted that growing conditions influenced the magnitude of the deleterious effects, with salinization of the soil slightly increasing tolerance to foliar-applied saline Water for leucaena. This study has demonstrated that whilst saline and Alkaline Water can potentially be used for overhead irrigation, differences in observed tolerance exist between plant species, and are influenced by growing conditions.
Federico D.f. Cicchelli - One of the best experts on this subject based on the ideXlab platform.
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Overhead-irrigation with saline and Alkaline Water: deleterious effects on foliage of Rhodes grass and leucaena
Agricultural Water Management, 2016Co-Authors: Federico D.f. Cicchelli, Neal W. Menzies, J. Bernhard Wehr, Scott A. Dalzell, Peter M. KopittkeAbstract:Abstract Saline and Alkaline Water represents a potentially valuable resource provided its irrigation does not decrease plant growth. Although the adverse effects of salts within the rooting environment are well-studied, comparatively little is known regarding the direct effects of overhead-irrigation of saline and Alkaline Water on plant foliage. The present study examined the potential deleterious effects of saline (electrical conductivity, EC, ≤15 dS m−1) and Alkaline (≤2000 mg L−1, CaCO3 equivalent) Water on foliage of Rhodes grass (Chloris gayana cv. Reclaimer) and leucaena (Leucaena leucocephala ssp. glabrata cv. Tarramba) under a range of growing-conditions. Foliage of leucaena was sensitive, with necrosis and chlorosis evident for saline Water at an EC ≥3 dS m−1 and Alkaline Water containing ≥500 mg L−1 (CaCO3 equivalent). For leucaena, this damage to the foliage reduced relative shoot fresh mass and chlorophyll fluorescence for saline-treatments, but alkalinity did not reduce relative shoot fresh mass or chlorophyll fluorescence in any treatment. In contrast to leucaena, relative shoot fresh mass of Rhodes grass was not reduced by foliar-applied salinity in any treatment (nor did alkalinity reduce growth of Rhodes grass). It was noted that growing conditions influenced the magnitude of the deleterious effects, with salinization of the soil slightly increasing tolerance to foliar-applied saline Water for leucaena. This study has demonstrated that whilst saline and Alkaline Water can potentially be used for overhead irrigation, differences in observed tolerance exist between plant species, and are influenced by growing conditions.
R.l. Leroy - One of the best experts on this subject based on the ideXlab platform.
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Separator materials for use in Alkaline Water electrolysers
International Journal of Hydrogen Energy, 2003Co-Authors: R. Renaud, R.l. LeroyAbstract:Abstract Separator materials suitable for use in industrial Alkaline Water electrolysers are surveyed, including both inorganic and organic materials. The properties which make asbestos diaphragms unsuitable for use above 100°C are also reviewed. In summary, potassium titanate and polyantimonic acid separator materials perform well in high-temperature alkali. Oxide-coated metallic diaphragms merit further attention. Polysulfone and polyphenylene sulfide polymers are promising, but will need definite improvement in their wettability. Asbestos stabilization by silicate electrolyte additions may be viable.
J. Bernhard Wehr - One of the best experts on this subject based on the ideXlab platform.
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Overhead-irrigation with saline and Alkaline Water: deleterious effects on foliage of Rhodes grass and leucaena
Agricultural Water Management, 2016Co-Authors: Federico D.f. Cicchelli, Neal W. Menzies, J. Bernhard Wehr, Scott A. Dalzell, Peter M. KopittkeAbstract:Abstract Saline and Alkaline Water represents a potentially valuable resource provided its irrigation does not decrease plant growth. Although the adverse effects of salts within the rooting environment are well-studied, comparatively little is known regarding the direct effects of overhead-irrigation of saline and Alkaline Water on plant foliage. The present study examined the potential deleterious effects of saline (electrical conductivity, EC, ≤15 dS m−1) and Alkaline (≤2000 mg L−1, CaCO3 equivalent) Water on foliage of Rhodes grass (Chloris gayana cv. Reclaimer) and leucaena (Leucaena leucocephala ssp. glabrata cv. Tarramba) under a range of growing-conditions. Foliage of leucaena was sensitive, with necrosis and chlorosis evident for saline Water at an EC ≥3 dS m−1 and Alkaline Water containing ≥500 mg L−1 (CaCO3 equivalent). For leucaena, this damage to the foliage reduced relative shoot fresh mass and chlorophyll fluorescence for saline-treatments, but alkalinity did not reduce relative shoot fresh mass or chlorophyll fluorescence in any treatment. In contrast to leucaena, relative shoot fresh mass of Rhodes grass was not reduced by foliar-applied salinity in any treatment (nor did alkalinity reduce growth of Rhodes grass). It was noted that growing conditions influenced the magnitude of the deleterious effects, with salinization of the soil slightly increasing tolerance to foliar-applied saline Water for leucaena. This study has demonstrated that whilst saline and Alkaline Water can potentially be used for overhead irrigation, differences in observed tolerance exist between plant species, and are influenced by growing conditions.
