Avaliação do processo de cogeração de energia em uma ETE com produção de biogás

Abstract

The process of energy cogeneration from the energetic use of biogas produced in sewage treatment plants (STPs) has been shown to be a promising practice to leverage sanitary sewage services in Brazil. In this context, the present work had the objective of investigating the possibility of using biogas, produced in UASB reactors of a medium-sized STP, for the realization of the energy cogeneration process. For this purpose, the electric power potential of the motor-generator set was compared to the energy demand of the STP. It was also raised if the thermal potential arising from the hot exhaust gases from the electric power generation system would be sufficient for the thermal drying of the sludge produced in the treatment plant itself. For the biogas and energy production estimates, ProBio 1.0 software was used, which took into account all the possible conversion routes of the organic matter inside a UASB reactor. Thus, the STP under study had a biogas production of (2,443 ± 1,236) Nm3.d-1 and a potential of electric power generation of (5,968 ± 3,020) kWh.d-1. With a power to be installed equal to 250 kW, the operation of the motor-generator set would compensate the station’s electric energy demand by approximately 51%, avoiding a cost of R$ 533,390.61 during the investigation period. In addition, the use of the thermal potential from the hot exhaust gases of the motor generator set, which is (4,241 ± 2,172) kWh.d-1, would supply about 41% of the energy demand required for the thermal drying of the sludge.