New Possibilities for Generating Oxygen and Hydrogen Using Electrolysis in Microgravity

Abstract

During short-term space mission years, the regeneration of air and provision of water is carried out on the basis of stocks, but their mass increases in direct proportion to flight duration and the number of members of the new crew. Therefore, in long orbital space missions to reduce cargo traffic of cargo ships is necessary to use systems based on regeneration oxygen, hydrogen, and water from waste products human activity. This is the recovery of drinking water from the condensate of atmospheric moisture and urine, obtaining oxygen and hydrogen by electrolysis of purified condensate or crew urine. The fundamental possibility of regenerative life support for a person, who finds located in a confined space, has been experimentally confirmed in long-term ground tests. Today on the International Space Station (ISS), the Russian module is equipped with an upgraded system "Electron-VM" for the production of oxygen and hydrogen on the basis of water electrolysis, containing liquid alkali, with increased capacity (80 ... 160 l / h), which allows providing oxygen up to six people. Water electrolysis system OGS operates in the American module of the ISS for oxygen production delivered to the ISS in 2008. The system is based on solid polymer electrolytes, which is its advantage; however, it requires additional water purification. The previously conducted theoretical description of the mechanism of formation of negatively charged electrolysis bubbles of hydrogen and oxygen under microgravity conditions confirmed experimentally, made it possible to establish the horizontal movement of negatively charged electrolysis hydrogen bubbles in a liquid from the cathode, where they were formed, to the anode due to the arising electrostatic force of attraction between the bubbles and the anode, and the horizontal movement of positively charged electrolysis oxygen bubbles in the liquid, from the anode, where they were formed to the cathode due to the arising electrostatic attraction force between the bubbles and the cathode. As a result, a concentrated gas-liquid mixture: oxygen bubbles + water is formed in the near-anode zone along the entire length of the anode; a concentrated gas-liquid mixture: oxygen bubbles + water is formed along the entire length of the cathode. Due to the conical shape of the developed electrolyzer and its outlets, under microgravity conditions, the separation draining of two gas-liquid mixtures into different ampules is carried out. These two different ampules, equipped with static separators, permit to separately obtain oxygen and hydrogen gases in microgravity that opening new possibilities of generating oxygen and hydrogen gases using electrolysis in microgravity capable of operating on the International Space Station. The paper presents an electrolyzer, designed on the basis of previously obtained theoretical data, confirmed experimentally, permitting economically and simply separately generate oxygen and hydrogen gases on the ISS.