Viabilidade técnica no reuso de resíduos da indústria de alimento e energia na produção de biodiesel

Abstract

The search for new renewable energy sources has triggered a series of researches focused on the biodiesel production process. In the midst of these researches, the current scenario points to a potential in the production of these biofuels with the use of waste. These residues may come from animal fat or from production processes. The production of biodiesel from these raw materials minimizes the use of high added value oilseed plants, and removes the cost of treatment of these residues, bringing a sustainability character to the entire chain. The main objective of this work is to investigate two different residues from the biodiesel production process, with the purpose of reusing these residues as raw material to the existing process. The investigated waste was transferred by a food and energy industry located in the Upper Uruguay region. The residues have different characteristics because they originate in different production processes. The first residue investigated was collected from the effluent treatment plant at the company's unit in Porto Real - RJ and is dark brown, characterized by having a high acid load. The second residue investigated was collected from the treatment plant at the Erechim - RS unit and is gray in color, characterized by containing high water concentration and soybean meal remnants. Regarding the characterization of the residue of the Porto Real unit, the results of the analyses were 3% moisture, 1577.29 μmol/ml of free fatty acids, 97.02/ % of oils and greases, 1.2 pH. These residues underwent different pre-treatment stages and were submitted to biodiesel production on a laboratory bench scale. The percentage of esters produced in a preliminary assay using sodium hydroxide as catalyst was 62.9%. For the residue collected in the Erechim unit, 94% moisture was obtained. This high concentration of water is characteristic of the enzymatic esterification used in the refining process of soybean oil, which originated this second residue. The concentration of free fatty acids found was 115 μmol/ml, Oils and greases 10.62/%, 5.52 pH. The preliminary tests of biodiesel production showed a percentage of ethers 87.40/%. These results indicate that the residues have the potential for reuse in biodiesel production and that these adjustments should still be made in the production process that generates this waste, leading to a more sustainable process minimizing the impact of waste generation on the environment.