Estudo do bio-óleo e carvão obtido a partir do lodo de tratamento de esgoto sanitário por conversão à baixa temperatura.

Abstract

The present study discusses an alternative to mitigate Sewage Sludge – SS problem. This residue adversely affects the environment in various ways, highlighting pollution of surface and groundwater. It aimed to use the biomass present in the SS for fuel production (Biooil and coal). It was an experimental study with biomass obtained from the Estação Experimental de Tratamento Biológico de Esgotos Sanitários – EXTRABES, located in the city of Campina Grande – PB. The experiment was conducted in two stages: first corresponding to thermogravimetric and kinetic study of the SS; second, obtainment of biooil and coal originated from the pyrolysis of SS, conducted at LABCOM, installed at the Fluminense Federal University – FFU. The results obtained from the thermogravimetric study in the three heating rates 5, 10 and 15oC min-1, found a thermal stability at 30°C on atmospheres of synthetic air and N2. In the kinetic study the following parameters were determined: Activation Energy (Ea), frequency factor (A-1), standard deviation (sd) and linear coefficient (r), that were calculated by thermogravimetry by the Coats-Redern (CR); Madhusudanan (MD); Van Krevelen (VK) and Horowitz-Metzger (HM) methods. The FTIR spectrums from the SS sample presented bands related to water, organic matter and silicon oxides. The biooil was obtained through the conversion at low temperature process, in nitrogen atmosphere, reaching 380oC with holding time of 2h. The pyrolysis process of the SS resulted in 9% of biooil, 57% of coal and 34% of pyrolysis water. It was observed that the biooil obtained is a complex mixture of aliphatic hydrocarbons, aromatics, steroids, nitrogenous and oxygenated compounds, which was identified by the FTIR, RMN 1H, CG-EM techniques. The coal presented low superficial area, not being considered a potentially good catalytic support, by the Langmuir methodology, SLANG 0,748 m2.g-1 as well as the BET, SBET = 0,695m2.g-1. The results confirm that the Conversion at Low Temperature is a promising technique, for both the destination of the SS as well as for the obtainment of biofuels.