Estudo do processo de pirólise termoquímica para produção de bio-óleo a partir do lodo de esgoto

Abstract

Due to the need to reduce emissions of greenhouse gases, the need for new sources of energy and minimization of environmental impacts caused by sewage sludge is evident. In this context the following work is directed to evaluate the bio- oil production, from thermochemical pyrolysis of the dry sewage sludge in the natural drying bed in a fixed bed reactor. The biomass was characterized by immediate and instrumental analysis (Elementary Analysis, C-200 Colorimetric Pump, Thermo gravimetric Analysis, phmetro, Conductivity Meter and Soxhlet Extractor). A TGA-simulated pyrolysis study was performed to evaluate the thermal stability of the organic matter degradation range (164,75 to 535,87 °C) under inert atmosphere. In the process of thermochemical pyrolysis, the influence of the variables: final temperature (450 to 550 °C), heating rate (10 to 30 °C / min), pyrolysis time (120 to 180 min) using a central composite design factorial 23) (DCC), accompanied by a response surface methodology, to determine the ideal conditions for the production of bio-oil. The bio-oil obtained was characterized by classical and instrumental analytical techniques. The maximum yield of the bio-oil was of the order of 16.20% m / m obtained under the temperature conditions of 550 °C, rate of 30 °C / min and time of 120 min. The lowest yield of the solid fraction was of the order of 53.75% m / m under the conditions of temperature 550 °C, rate 30 °C / min and time of 180 min. The bio-oil showed the following characteristics: pH (between 7.66 and 9.68), density (between 0.99 and 0.98 g/cm3), viscosity (between 53.37 and 56.40 cSt), (between 31.37 and 37.82 Mj/kg), corrosivity (1b), humidity (between 2.84% and 6.48% m/m) and average chemical composition equal to CH1,54N0,07O0,12. The results of the thermo gravimetric analysis (TGA) showed that the bio-oil contains a considerable amount of light compounds with boiling point <350 ° C corresponding to 85.04% of the mass of the bio-oil analyzed.