Energy balance of small scale biogas system for family farming agriculture

• Ano de defesa: 2017
• Autor(a) principal: Praciano, Aline Castro
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Palavras-chave em Português: Esterco bovino; Poder calorífico superior; Energias renováveis
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/40067

Biogas is an important renewable energy in the rural areas, for it can be generated from the manure of livestock, such as bovines, swine, goats, sheep and birds. This biofuel can be converted into electric and thermal energy, which allows several economic and environmental gains for rural areas, especially for the family agriculture because of the savings resulted from the reduction of costs with electricity and gas for cookery (LGP - Liquefied Gas of Petroleum). Beyond that, benefits to the environment such as the reduction of Greenhouse Gas Emission (GGE), deforestation of the biome caatinga, contamination of soil and aquifers. The electricity generated by biogas can be used in several sectors of agriculture such as illumination for agricultural, zootechnical and residential facilities, agricultural equipment operations, such as motor pumps, forage, and milking machines. This biofuel can also be used for generating thermal energy, which takes the place of cooking gas or firewood for cookery or for animal welfare by heating the sheds, as for swine and poultry. In the present study, we assessed the biogas production from bovine manure, the methane concentration of crude and purified biogas (filters of in silica gel and activated carbon) by gas chromatography, the conversion from biogas to electric and thermal energy, the consumption of biogas of a 0.33 HP irrigation motor pump, 12, 16 and, 24 W LED bulbs, and a two-flame stove, we determined the calorific value of fresh and digested manure, and of the bio-fertilizer, and we conducted the chemical evaluation of the bio-fertilizer. The study aimed to evaluate the energy balance of the converting thermodynamic system from bovine manure into biogas generated in a PVC (polyvinyl chloride) tubular digester plant and the energy efficiency by determining the higher calorific power of products involved. The assessed thermodynamic system had energy balance of 142.75 MJ and energy efficiency of 89.30%.