MODERN BIOTECHNOLOGIES AND EQUIPMENT FOR OBTAINING HYDROGEN (REVIEW)

Abstract

Comparative characteristics of the composition of the gas formed during the combustion of methane and hydrogen are provided. It is emphasized that hydrogen is the only fuel that does not pollute the environment and can be used as one of the possible ways to overcome the global energy crisis. The purpose of the work is an analytical review of modern biotechnologies for obtaining hydrogen.In modern conditions, considerable attention is paid to the development of ecologically clean biotechnologies for obtaininghydrogen from various wastes. The raw material for its production can be natural and wastewater, solid waste from the food,woodworking and agricultural industries.The biotechnologies of obtaining hydrogen from various production wastes, in particular cellulose wastes using the technologyof two-stage fermentation in anaerobic reactors, are considered. At the first stage, the process of destruction of high-polymericcompounds into low-polymeric compounds took place. The main technological parameters of the first stage of anaerobic fermentation: pH 5-6; mesophilic conditions (35±5o C). The duration of the process is 5 days. In the reactors of the 2nd stage, at neutral pH values of 7-8, the process of hydrogen production and subsequent destruction of cellulose-containing waste took place. Examples of hydrogen production in the process of photosynthesis of green algae, cyanobacteria, and purple algae in industrial photo bioreactors of closed and open types are given. The rates of hydrogen release by different types of algae and bacteria aregiven. It is indicated that in order to achieve stable production of bio hydrogen, photo bioreactors must be made in the form of hermetic structures with a large-area transparent case.When designing an industrial photoautotrophic cultivator under sunlight conditions, the intensity of solar radiation at the beginning and end of daylight is taken into account. Technologies for obtaining hydrogen using bio electrochemical systems and photo electrochemical microbial fuel cells are considered.