Estudo da transferência de calor em biodigestores do tipo plug-flow com três tipos diferentes de cores de gasômetros e inserção de isolante térmico

Abstract

Biogas is one of the branches of renewable energy that is advancing today, mainly due to studies, projects and laws that are being created to further encourage this technology. This work aims to demonstrate the functioning of heat transfer in plug-flow type digesters. It is known that these have large areas for capturing solar radiation, resulting in heat gain internally. In this way, this study verified the effect of the color of the gasometer canvas, in addition to the addition of thermal insulation in the biodigesters, in order to analyze the energy gain due to solar radiation, besides verifying which is the best case for the biodigesters covered lagoon type operate at higher temperatures and are more stable. For this, four biodigesters with dimensions of 2.1x0.7x0.4 m were built and analyzed, with three types of tarpaulins with and without thermal insulation being applied, one with white tarpaulin and one with black tarpaulin without insulation and the other two with tarpaulins transparent and black with the addition of thermal insulation, all being operated in the same conditions of the environment. The experiment was carried out in the city of Foz do Iguaçu, between the period 02/09/2019 until 03/10/2019, where it obtained as a result that the biodigester of transparent gasometer with thermal insulator had the highest average temperature, but also the greatest variation This fact occurred mainly because of the temperature difference between the environment, the soil and the biomass. The black gasometer biodigester and the addition of insulation had the second highest average temperature and thermal variation. The black gasometer and white gasometer digesters, on the other hand, had the lowest average temperatures and thermal variations respectively, with the white canvas biodigester being the most thermally stable. In addition, it was found that the greatest heat loss occurs from biomass to biogas.