The Experts below are selected from a list of 10524 Experts worldwide ranked by ideXlab platform
R. B. Merie - One of the best experts on this subject based on the ideXlab platform.
-
Solid acids as fuel cell electrolytes
Nature, 2001Co-Authors: Sossina M. Haile, C. R I Chisholm, Dane A. Boysen, R. B. MerieAbstract:Fuel cells are attractive alternative to combustion engines for electrical power generation because of their very high efficiencies and low pollution levels. Polymer electrolyte membrane fuel cells are generally considered to be the most viable approach for mobile applications. However, these membranes require humid operating conditions, which limit the temperature of operation to less than 100°C; they are also permeable to methanol and hydrogen, which lowers fuel efficiency. Solid, inorganic, acid compounds (or simply, solid acids) such as CsHSO 4 and Rb 3 H(SeO 4 ) 2 have been widely studied because of their high proton coductivities and phase-transition behaviour. For fuel-cell applications they offer the advantages of anhydrous proton transpot and high-temperature stability (up to 250°C). Until now, however, solid acids have not been considered viable fuel-cell electrolyte alternatives owing to their solubility in water and extreme ductility at raised temperatures (above approximately 125° C). Here we show that a cell made of CsHSO 4 electrolyte membrane (about 1.5 mm thick) operating at 150-160°C in a H 2 /O 2 configuration exhibits promising electrochemical performances: open circuit voltages of 1.11V and current densities of 44 mA cm -2 at short circuit. Moreover, the solid-acid properties were not affected by exposure to humid atmospheres. Although these initial results show promise for applications, the use of solid acids in fuel cells will require the development of fabrication techniques to reduce electrolyte thickness, and an assessment of possible Sulphur Reduction following prolonged exposure to hydrogen.
M Michael Golombok - One of the best experts on this subject based on the ideXlab platform.
-
Sulphur and viscosity Reductions in heavy hydrocarbons by subcritical water processing
Journal of Petroleum Science and Engineering, 2019Co-Authors: Michel Cuijpers, Michael Boot, Ng Niels Deen, M Michael GolombokAbstract:Abstract Viscosity and Sulphur content are two important properties of heavy hydrocarbons for downstream processing. Both properties can be significantly reduced in value by processing in subcritical water. Subcritical water has advantages over steam recovery methods in terms of viscosity and Sulphur Reduction as well as energy consumption. In order to understand the mechanism of subcritical water treatment, the chemical structure of pre- and post-processed heavy hydrocarbons are compared to each other. For subcritical water processing, viscosity Reduction coincides with a Reduction in average molecular weight, average carbon chain length between branching points, and Sulphur content, along with an increase in volatility and H2S production. This suggests that not only are C C bonds cracked, but also C S-(C) bonds. Subsequent comparison of subcritical water results with those obtained for pyrolysis treatment shows that the former is faster and more effective.
Golombok M Michael - One of the best experts on this subject based on the ideXlab platform.
-
Sulphur and viscosity Reductions in heavy hydrocarbons by subcritical water processing
Elsevier, 2019Co-Authors: Cuijpers, Mcm Michel, Boot, Md Michael, Deen, Ng Niels, Golombok M MichaelAbstract:\u3cp\u3eViscosity and Sulphur content are two important properties of heavy hydrocarbons for downstream processing. Both properties can be significantly reduced in value by processing in subcritical water. Subcritical water has advantages over steam recovery methods in terms of viscosity and Sulphur Reduction as well as energy consumption. In order to understand the mechanism of subcritical water treatment, the chemical structure of pre- and post-processed heavy hydrocarbons are compared to each other. For subcritical water processing, viscosity Reduction coincides with a Reduction in average molecular weight, average carbon chain length between branching points, and Sulphur content, along with an increase in volatility and H\u3csub\u3e2\u3c/sub\u3eS production. This suggests that not only are C–C bonds cracked, but also C–S-(C) bonds. Subsequent comparison of subcritical water results with those obtained for pyrolysis treatment shows that the former is faster and more effective.\u3c/p\u3
Sossina M. Haile - One of the best experts on this subject based on the ideXlab platform.
-
Solid acids as fuel cell electrolytes
Nature, 2001Co-Authors: Sossina M. Haile, C. R I Chisholm, Dane A. Boysen, R. B. MerieAbstract:Fuel cells are attractive alternative to combustion engines for electrical power generation because of their very high efficiencies and low pollution levels. Polymer electrolyte membrane fuel cells are generally considered to be the most viable approach for mobile applications. However, these membranes require humid operating conditions, which limit the temperature of operation to less than 100°C; they are also permeable to methanol and hydrogen, which lowers fuel efficiency. Solid, inorganic, acid compounds (or simply, solid acids) such as CsHSO 4 and Rb 3 H(SeO 4 ) 2 have been widely studied because of their high proton coductivities and phase-transition behaviour. For fuel-cell applications they offer the advantages of anhydrous proton transpot and high-temperature stability (up to 250°C). Until now, however, solid acids have not been considered viable fuel-cell electrolyte alternatives owing to their solubility in water and extreme ductility at raised temperatures (above approximately 125° C). Here we show that a cell made of CsHSO 4 electrolyte membrane (about 1.5 mm thick) operating at 150-160°C in a H 2 /O 2 configuration exhibits promising electrochemical performances: open circuit voltages of 1.11V and current densities of 44 mA cm -2 at short circuit. Moreover, the solid-acid properties were not affected by exposure to humid atmospheres. Although these initial results show promise for applications, the use of solid acids in fuel cells will require the development of fabrication techniques to reduce electrolyte thickness, and an assessment of possible Sulphur Reduction following prolonged exposure to hydrogen.
Erling Rytter - One of the best experts on this subject based on the ideXlab platform.
-
Effect of nickel and vanadium on Sulphur Reduction of FCC naphtha
Applied Catalysis A: General, 2000Co-Authors: Trond Myrstad, B. Seljestokken, Hege Engan, Erling RytterAbstract:Abstract A number of solutions to reduce Sulphur in fluid catalytic cracking (FCC) naphtha have been suggested. One of these is to reduce the Sulphur content in the FCC reactor by using an FCC catalyst or an FCC catalyst additive. In most of the published laboratory investigations within this field, steam-deactivated, metal-free FCC catalysts have been used. This study discusses the effects of nickel and vanadium present on the FCC catalyst with respect to the Sulphur level in FCC naphtha. The effects of these metals are discussed both in the absence and the presence of a Sulphur-Reduction additive. The study shows that the Sulphur level in FCC naphtha is significantly lower when testing with metal-impregnated catalysts as in the case when testing the catalysts in the absence of metals. The study also shows that, when mixed with metal-impregnated catalysts, the effect of a Sulphur-Reduction additive is prohibited.
-
Sulphur Reduction of fluid catalytic cracking (FCC) naphtha by an in situ Zn/Mg(Al)O FCC additive
Applied Catalysis A: General, 1999Co-Authors: Trond Myrstad, B. Seljestokken, Hege Engan, Erling RytterAbstract:Abstract A number of solutions for the Reduction of Sulphur in fluid catalytic cracking (FCC) naphtha have been suggested. One possible solution would be to use an FCC catalyst or an FCC catalyst additive which could reduce the Sulphur content in the FCC naphtha in situ in the cracker itself. Through this work, it has been shown that an FCC-additive made by impregnating zinc on a hydrotalcite-like material is able to give a significant Reduction of naphtha Sulphur in MAT experiments, while the hydrotalcite material itself gives only a minor Reduction of naphtha Sulphur. It has also been shown that the additive has no effect on catalyst activity, but gives an unwanted increase in the production of coke.
