Estudo da produção do biogás e a aplicação de uma análise exergoeconômica para um sistema de cogeração usando biometano

Abstract

The present work addresses the energetic and exergoeconomic analysis of a cogeneration system that uses biomethane for energy generation and absorption refrigeration. This system consists of biodigesters, a Leon Heimer generator set with a power of 100 kW and an ACF60-00 absorption refrigerator from the ROBUR brand. Two types of biodigesters were developed for the production of biomethane: one with 5 containers in series and the other using a 200-liter drum. The latter demonstrated the capacity to produce biogas, while the former did not demonstrate this capacity; both were evaluated over a two-month period. Furthermore, purifying filters connected to the biodigesters were implemented to convert biogas into biomethane. To assess the effectiveness of the purifiers, the temperature was measured in the solid regions of the flame using a 20A800G Cativ 12V 640X480 FLKTI480PRO9HZBR Fluke thermal camera, measuring an average temperature of 33ºC, which promotes the activity of mesophilic anaerobic microorganisms in the methanogenesis process, contributing to increase the concentration of methane in biogas. The theoretical estimate demonstrated that, from 133.33 kg of organic matter introduced into the biodigester, 95.6% of the waste was used, resulting in 17,471.748 liters of biogas and 292.47 kg of biofertilizer. In relation to the energy and exergoeconomic analysis, the production of 32.0396 kWh of electrical energy and 23.9093 kWh of cold energy was found. Finally, in order to reduce the period of return on investment (ROI) of the cogeneration system, an exergoeconomic analysis was carried out considering a volume 50 times greater than the biodigester, resulting in an ROI of 7 years