CC BY
10
УДК 662.767.2
Sultanov B.S. assistant
faculty of«Medicinal and Biological Chemistry» Ferghana Medical Institute of Public Health
Uzbekistan, Ferghana
UTILIZATION OF AGRICULTURAL WASTE IN THE PRODUCTION
OF BIOGAS
Annotation. This article discusses the production process of biogas through bacterial bacteria. Battery systems consist of reactors in which the substrate is fermented before it is discharged. The periodic production of biogas includes the supply of the starting material, the seed material and the discharge of the finished product into the reactor. Such a system has a rather high labor intensity, requires the presence of several reactors for the discharge of the source gas and a tank for storing manure in the tank.
Keywords: bioreactor, biogas, hydrogen sulfide, dehumidifier, drying, carbon dioxide, absorber.
The raw materials for the production of biogas are, first of all, a variety of organic waste from the agro-industrial complex, which is rich in cellulose and other polysaccharides. The conversion of organic waste into biogas occurs as a result of a whole complex of complex biochemical transformations. This process is called the fermentation of biomass. It occurs only thanks to bacteria and is carried out in special technological installations of fermenters. Biogas plants are also equipment for processing manure and other organic waste.
Currently, a fairly large number of technologies for producing biogas have been developed and applied, based on the use of various variations in temperature, humidity, bacterial mass concentrations, duration of bioreactions, and so on, while the methane content in biogas varies depending on the chemical composition of raw materials and can range from 50 to 90%. Organic matter disintegrates in bioreactors.
A significant part of the components passes into the gas and into the solution. Fermentation is called methane because one of the main end products of the decomposition of organic substances is methane [1].
The general scheme of methane fermentation is proposed by Barker. He considers the whole process to consist of two phases. In the first phase (acidic or hydrogen fermentation), acids (acetic, formic, lactic, butyric, propionic, etc.), alcohols (ethyl, propyl, butyl, etc.), gases (carbon dioxide, hydrogen, hydrogen sulfide, ammonia), amino acids, glycerin, etc. are formed from complex organic substances with the participation of water. This decay is carried out by ordinary saprophytic anaerobic bacteria, which are widespread in nature, multiply rapidly,
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and live at a pH of 4.5-7. Acid fermentation is characterized by the abundant formation and release of acids, which is accompanied by acidification of the medium and a decrease in pH to 5-4.5, as well as the appearance of an unpleasant putrid odor [2].
In the second phase (alkaline or methane fermentation), methane-forming bacteria carry out the further decomposition of substances formed in the first phase. By this releases a gas consisting of methane, carbon dioxide, hydrogen, and nitrogen. The Barker scheme does not have a strict thermodynamic basis. However, the idea of two phases of the process is quite convenient for conducting technological control, and this is widely used in practice [3].
Other researchers believe that three stages should be distinguished in the anaerobic destruction of organic matter, and three physiological groups are distinguished bacteria. At the first stage, a heterogeneous group of anaerobic bacteria, the so-called "primary" anaerobes, are subjected to enzymatic hydrolysis of complex multi-carbon substances representing the main classes of organic compounds - proteins, lipids, and polysaccharides. At the same time, together with the bacteria that carry out the hydrolysis of polymers, they function as microorganisms that break down monosaccharides, organic acids, alcohols, and methanol. The result of the activity of these microorganisms is the formation of hydrogen, carbon dioxide, low molecular weight fatty acids, and alcohols, as well as some other compounds.
References:
1. Blagutina V.V. Bioresources // Chemistry and life, 2007. No. 1. pp. 36-39.
2. Malofeev V.M. Biotechnology and environmental protection: Textbook. M.: Publishing House Arktos, 1998. 188 p.
3. Marinenko E.E. Fundamentals of obtaining and using biofuels to address energy conservation and environmental protection issues in housing and communal services and agriculture: Study guide. Volgograd: VolgGASA, 2003. 100 p.
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