Analysis of Thermal and Catalytic Pyrolysis Processes in Belém: A Socioeconomic Perspective

This study aims to assess the by-products generated through the thermal and catalytic pyrolysis of the organic matter and paper fractions of municipal solid waste (MSW) in different socioeconomic regions, through the yields of reaction products (bio-oil, biochar, H2O, and gas), acid value and chemical composition of bio-oils, and characterization of biochar, on a laboratory scale. The organic matter and paper segregated from the gravimetric composition of the total waste sample were subjected to drying, crushing, and sieving pre-treatment. The experiments were carried out at 450 °C and 1.0 atmosphere, and at 400 °C and 475 °C and 1.0 atmosphere, using a basic catalyst, Ca(OH)2, at 10.0% by mass, in discontinuous mode. The bio-oil was characterized by acidity value and the chemical functions present in the bio-oil identified by FT-IR, NMR, and composition by GC-MS. The biochar was characterized by SEM/EDS and XRD. The bio-oil yield increased with the addition of the catalyst and the pyrolysis temperature. For catalytic pyrolysis, bio-char and gas yields increased slightly with the Ca(OH)2 content, while bio-oil and H2O phases remained constant. The GC-MS of the liquid reaction products identified the presence of hydrocarbons and oxygenates, as well as nitrogen-containing compounds, including amides and amines. The acidity of the bio-oil decreased with the addition of the basic catalyst in the process. The concentration of hydrocarbons in the bio-oil appeared with the addition of the catalyst in the catalytic pyrolysis process as the catalytic deoxygenation of fatty acid molecules occurred, through decarboxylation/decarbonylation, producing aliphatic and aromatic hydrocarbons, introducing the basic catalyst into the thermal process.