Biogas

Biogas is a methane-rich gas. The methane content is from 50 to 85%. It also contains 15 to 40% carbon dioxide, nitrogen, hydrogen, oxygen and hydrogen sulphide. Biogas is obtained as a result of fermentation processes in anaerobic environment (without oxygen) of biological products at strictly determined temperatures. The initial raw materials used for the production of biogas include waste from animal farms - manure, litter (a mixture of manure and straw), waste water from washing, food wastes. These materials contain organic and non-organic materials and therefore are a suitable environment for the development of microorganisms. They represent a serious issue due to the fact that they may accumulate and pollute the environment. During their natural fermentation is released methane which is a greenhouse gas and accounts for 7 to 10% of the global methane pollution. The energy content of biogas is around 22 600 KJ/m or 5400 ccal/m (1 KJ = 4 185 ccal). The caloricity of 1 kg of methane corresponds to the one of 1,18 kg of black oil, i.e. 1m of methane = 1l of black oil bearing in mind that one cubic meter of methane at atmospheric pressure and a temperature of 15ºC has a mass of 718 grams. Out of 1 kg of biomass (as dry matter) may be obtained 200 to 1200 litres of biogas depending on the composition of the biomass and the conditions of the fermentation. Biogas may be used for the production of electrical energy, heat energy and methane. The biogas installations and their fermentation tanks in particular serve to store the methane obtained during the fermentation. The carbon dioxide which accompanies methane in biogas composition is not more than the one which is produced during the natural fermentation of wastes. The residual products of methanogenic fermentation are water and deodorized and decontaminated biological fertilizer with a higher concentration of minerals and micro-elements and an easier to absorb by plants form of nitrogen.

The company is planning to process a sufficient amount of land in order to satisfy its need for feedstock necessary for reaching the production capacity of 100 000 t/y of biodiesel as well as the corresponding sowing turnover. As a result of this activity around 150 000 t/y dry biomass is generated to be used for production of biogas. The process of anaerobic decomposition is performed in bioreactors operating in thermophilic mode.

carbohydrates ________                                                                                                                             СО2
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fats ________________ | ___hydrolysis ____ acidogenesis ____ acetogenesis ____ methanogenesis
                                            |                                                                                                                              |

proteins _____________|                                                                                                                           СН4 

It is used for co-generation and internal technological needs. A module for purification of biogas until receiving biomethane (intended for use as transportation fuel) is under construction.

After the releasing of biogas, the secondary biomass is analyzed, its nutritious properties are established (CB, volatile, pH, P, K, N) and is used for fertilizing agricultural land thereby substituting artificial mineral fertilizers.