Pirólise de casca de soja in natura e hidrolisada

Abstract

The study aimed to evaluate the obtaining of bio-oil and bio-char through the pyrolysis process from fresh soybean hulls hydrolyzed by subcritical water. The biomass was characterized according to its lignocellulosic composition, particle size and high heating value. The subcritical water hydrolysis experiments were carried out at different temperature conditions (230 ºC and 260 ºC), in order to evaluate the difference in the yield of fermentable sugars in the hydrolyzed solution. Using high performance liquid chromatography analysis, the highest yield of sugars (2.67 g sugars/100 g of biomass) was obtained using a temperature of 230 °C. The pyrolysis procedures for fresh soybean hulls and the solid remaining from hydrolysis used temperature (400 °C and 600 °C) and heating rate (30 and 60 °C/min) as variables. The yields of bio-oil, bio-char and bio-gas were analyzed. The pyrolysis process at 600 °C with a heating rate of 60 °C/min, using remaining solids from SWH, resulted in the highest yield of bio-oil (38.80%). Using Fourier transform infrared spectroscopy (FTIR) in bio-oil samples, it was possible to observe the presence of functional groups characteristic of compounds such as carboxylic acids, phenols, alcohols, ketones and aldehydes. For the bio-char samples, the functional groups observed by FTIR were mainly hydroxyls, methyl and aromatic groups. The highest calorific value presented by the bio-char samples was 28.9 MJ/kg for the conditions of 600 °C and 60 °C/min with hydrolysis solid co-product.