Avaliação da pirólise catalítica do resíduo da indústria cervejeira

Abstract

The large availability of agro-industrial waste and the search for alternative sources of energy generation and chemical compounds become the pyrolysis an attractive strategy. Pyrolysis consists of the thermal conversion of biomass, by breaking of the components: extractives, hemicellulose, cellulose and lignin for coal, bio-oil and gas production. These products have a higher energy density than in nature biomass. Thus, the objective of this work was to study the catalytic and noncatalytic pyrolysis of malt bagasse by analyzing the effect of pyrolysis temperature and magnesium chloride concentration on product yields and main characteristics. They were evaluated as physical and chemical properties of biomass through particle size distribution, density and employing the analyzes: elemental, immediate, Fourier transform infrared spectroscopic (FTIR), lignocellulosic and thermogravimetric composition. Degradation kinetics have been estimated using a Differential Avoidance Algorithm. Reparametrized global reaction model and reparametrized independent parallel reaction model were employed based on dynamic thermogravimetry (TGA) data. TGA was performaed for pure malt bagasse with heating rate of 10, 20, 30, 40 and 50 K / min, while for a catalyst biomass, tests were performed at 40 K / min, at 5 and 10% additive mass concentrations. Pyrolysis was performed in a fixed bed and the experimental scenario was determined through a three-level factorial design, with temperatures of 723, 773 and 823 K and concentration of magnesium chloride of 0, 5 and 10%. Yields of products were determined by gravimetry. Coal characterization made by FTIR and organic fraction of the liquid product characterized by gas chromatography coupled to the mass spectrometer (CGMS). The results of biomass characterization showed in promising to use malt bagasse in the pyrolysis process. In addition, the results indicated lower activation energy than other biomasses, a fact that makes possible an application in pyrolysis processes. The presence of magnesium chloride had a catalytic effect on the thermal decomposition process. The variables were significant in the product generation process. Bio-oil yield was maximized by higher temperatures and increased additive concentration. As well as yield, the presence of additive favored the selectivity of pyrolytic products, forming mostly esters. Finally, the increase in additive favored coal production, associated with lower temperatures. As for gases, there was a significant reduction with the use of the catalyst.