Automatic control system of O2

The Institute of Biophysics SB RAS is developing a physical experimental model of a closed ecosystem (EMCS) simulating mass-exchange flows in the presence of a calculated proportion of human metabolism. The model is de- signed to check the compatibility of the higher plant link with the biological and physicochemical links in the process- ing of organic wastes that are being developed. In this connection, the EMCS does not contain a number of auxiliary reactors (decomposition of urea, nitrification of ammonia and synthesis of hydrogen peroxide), the direct interaction of which with the plant link is either excluded, or do not have a negative impact on cultivated plants. The absence of these reactors leads to an imbalance in the flow of substances in the system; in particular, excess oxygen is formed as a result of the process of “wet combustion” of organic wastes in hydrogen peroxide. To compensate for the model gas balance, a special gas circuit is developed in which oxygen is removed by binding to hydrogen obtained by electrolysis of off- system water. To control this process, an automatic gas concentration monitoring system has been developed that allows maintaining the concentration of hydrogen in a safe range without an operator's presence, stopping the process by achieving the required oxygen concentration, and also recording the sensor readings into the database for further processing. In addition to the proposed methodological approach, the developed control system can be used in full- scale biotechnical life-support systems to monitor the oxygen / hydrogen composition of a gas medium in a gas circuit of other physicochemical processes, for example, in the synthesis of hydrogen peroxide and ammonia nitrification.