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A simple miniaturized methanol-feed control for fuel cells
P. G. P. ANG, H. H. EWE, E. W. JUST1 and A. W. KALBERLAH, Institut fiir Technische Physik, Technische Universitlt, Mendelssohnstrasse lB, D-33 Braunschweig, West Germany. A simple miuiaturized methanol-feed (1972).
control for fuel cells: Energy Conversion 12, 65-68
Summary-For fuel cells operating with liquid feeds dissolved in the electrolyte a control of fuel concentration is indispensable. For this purpose we have constructed a fuel control device, which is able to control the CHaOH concentration in the electrolyte reliably and differs from constructions published already by its simplicity and smallness. The sensor consists of a simple compartment inserted in the electrolyte circulation of the fuel cell and containing two electrodes. In the case of alkaline electrolytes the anode consists of a nickel sheet, and the cathode of a Raney nickel DSK electrode. If no fuel is dissolved in the electrolyte oxygen evolution occurs at the anode. No oxygen evolution occurs if the electrolyte contains dissolved fuel as, for example, methanol, but instead of this the CHaOH is oxidized anodically, whereby the anode potential and measuring voltage between cathode and anode is decreased. This voltage change is used as measuring signal for injection of fuel. Potentiodynamic experiments have confirmed that the oxide NiOOH is a very active catalyst for the anodic oxidation of methanol. The influences of the various operating parameters, e.g. temperature, KOH and K&03 concentration are investigated, and eliminated without use of a computer. Besides methanol even hydrazine reacts in a similar manner with the nickel sheet anode and, therefore, this simple transducer may also be used for hydrazine concentration control. Platinum anodes are also well suited, but too expensive. For acid electrolytes lead is a good and cheap anode electrode material. For the automatic control of fuel concentration using the above described sensor a miniaturized inexpensive reliable electronic construction is described, and in conclusion compared with other systems published previously by other authors. Key words: dissolved fuel fuel cells
G. ANGELINO, Italy.
fuel control device
methanol
hydrazine
Istituto di Macchine, Politecnico, Piazza Leonardo da Vinci, 32-Milano,
The potential role of jet compression in high temperature energy conversion: Energy Conversion 12, 69-75 (1972). Summary-In power cycles the possibility of handling working fluids at very high temperatures and pressures by a preliminary reduction of both these parameters through a mixing process is discussed. In order to attain the highest effectiveness with respect to total temperature reduction and, at the same time, in order to restrain within acceptable limits the losses which are intrinsically associated with any mixing process, the best working fluid combination is found to be that of a high molecular weight metal vapor, acting as driving fluid and of a light gas serving as auxiliary fluid. In the case of the uranium-hydrogen combination, for instance, the addition of 5% hydrogen at 2700°K to a uranium vapor jet at a total temperature of 6000°K and at a static temperature of 4000°K gives rise to a mixture which retains the greatest part of the mechanical energy of the metal vapor jet and whose total temperature is of only 3300°K. Total pressure and Mach number undergo a similarly important reduction. After the mixing process has altered, in the desired direction, the thermodynamic parameters at which fluid power is available, an MHD or a mechanical device utilizes the energy of the mixture. In addition to the description of the basic characteristics of uranium-hydrogen cycles, the performance of other cycles, suitable for a lower temperature level and employing bismuth as working fluid and helium as auxiliary gas are reported. Key words: high temperature uranium as working fluid drop
Rankine cycles cavity reactor mixing bismuth as working fluid
...
n1
nuclear space power total temperature
control for fuel cells: Energy Conversion 12, 65-68
Summary-For fuel cells operating with liquid feeds dissolved in the electrolyte a control of fuel concentration is indispensable. For this purpose we have constructed a fuel control device, which is able to control the CHaOH concentration in the electrolyte reliably and differs from constructions published already by its simplicity and smallness. The sensor consists of a simple compartment inserted in the electrolyte circulation of the fuel cell and containing two electrodes. In the case of alkaline electrolytes the anode consists of a nickel sheet, and the cathode of a Raney nickel DSK electrode. If no fuel is dissolved in the electrolyte oxygen evolution occurs at the anode. No oxygen evolution occurs if the electrolyte contains dissolved fuel as, for example, methanol, but instead of this the CHaOH is oxidized anodically, whereby the anode potential and measuring voltage between cathode and anode is decreased. This voltage change is used as measuring signal for injection of fuel. Potentiodynamic experiments have confirmed that the oxide NiOOH is a very active catalyst for the anodic oxidation of methanol. The influences of the various operating parameters, e.g. temperature, KOH and K&03 concentration are investigated, and eliminated without use of a computer. Besides methanol even hydrazine reacts in a similar manner with the nickel sheet anode and, therefore, this simple transducer may also be used for hydrazine concentration control. Platinum anodes are also well suited, but too expensive. For acid electrolytes lead is a good and cheap anode electrode material. For the automatic control of fuel concentration using the above described sensor a miniaturized inexpensive reliable electronic construction is described, and in conclusion compared with other systems published previously by other authors. Key words: dissolved fuel fuel cells
G. ANGELINO, Italy.
fuel control device
methanol
hydrazine
Istituto di Macchine, Politecnico, Piazza Leonardo da Vinci, 32-Milano,
The potential role of jet compression in high temperature energy conversion: Energy Conversion 12, 69-75 (1972). Summary-In power cycles the possibility of handling working fluids at very high temperatures and pressures by a preliminary reduction of both these parameters through a mixing process is discussed. In order to attain the highest effectiveness with respect to total temperature reduction and, at the same time, in order to restrain within acceptable limits the losses which are intrinsically associated with any mixing process, the best working fluid combination is found to be that of a high molecular weight metal vapor, acting as driving fluid and of a light gas serving as auxiliary fluid. In the case of the uranium-hydrogen combination, for instance, the addition of 5% hydrogen at 2700°K to a uranium vapor jet at a total temperature of 6000°K and at a static temperature of 4000°K gives rise to a mixture which retains the greatest part of the mechanical energy of the metal vapor jet and whose total temperature is of only 3300°K. Total pressure and Mach number undergo a similarly important reduction. After the mixing process has altered, in the desired direction, the thermodynamic parameters at which fluid power is available, an MHD or a mechanical device utilizes the energy of the mixture. In addition to the description of the basic characteristics of uranium-hydrogen cycles, the performance of other cycles, suitable for a lower temperature level and employing bismuth as working fluid and helium as auxiliary gas are reported. Key words: high temperature uranium as working fluid drop
Rankine cycles cavity reactor mixing bismuth as working fluid
...
n1
nuclear space power total temperature