IMPROVEMENT OF THE PROCESS OF OBTAINING THE HYDROGEN BY USING SODIUM BOROHYDRIDE
Abstract
The process of hydrogen obtaining by hydrolysis of a suspension of sodium borohydride (NaBH4) in mineral oil has been developed, which, in combination with fuel cells, is intended for use in power plants of unmanned aerial vehicles (UMAVs). The created process allows to avoid a possible UMAVs explosion in the event of using the previously developed sodium borohydride hydrolysis process stabilized with caustic soda solution.
A comparison of the characteristics of these two technological processes is given.
For the alkaline process during the use of a capacitive reactor, the calculation method is made taking into account the calculation sequence of evaporators with natural circulation, thermodynamic and kinetic patterns of reactions, as well as test data of experimental reactors.
For NaBH4 oil suspension hydrolysis devices, a method recommended by the standards for calculating film evaporators is proposed.
The replacement of the capacitive reactor and related alkaline systems with a film device is justified, which will allow to increase the controllability of the UMAVs power plant and improve the heat release into the environment. The film apparatus provides a two to three times increase in the intensity of heat and mass transfer between phases.
The kinetics of the process of interaction of NaBH4 oil suspension with water was studied in a volume reactor
1,13×10–3 m3 (inner diameter 72×10–3 m3, length 0,24 m).
The use of NaBH4 oil suspensions for obtaining hydrogen allows to eliminate overheating and organize a uniform process. At the same time, it is possible to increase efficiency by reducing hydrogen losses during storage and eliminating NaBH4. The oil is regenerated and reused. The study of the hydrolysis of NaBH4 oil suspensions was carried out within the limits of changing the parameters corresponding to the operating modes of autonomous installations.
It is shown that NaBH4/oil mass ratios of 1:8 and 1:5 are optimal. 15% suspension of NaBH4 (ratio 1:5) is more viscous, therefore, 10% suspension of NaBH4 (ratio 1:8) is recommended for use.
References
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