Valorization of waste cooking oils through conversion processes catalysed by choline hydroxide

• Autor(a) principal: Gué, Yara
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10198/24732
• topic: Biodiesel production; Transesterification; Ionic liquids; Choline Hydroxide; Response surface methodology; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

Biodiesel is a biofuel produced from renewable biomass through the reaction of transesterification of triglycerides through an alcohol in the presence of a catalyst. Interest in this fuel is related to the search for alternatives to petroleum-based energy sources. This is associated with several environmental benefits, such as a reduction in the emission of pollutants. However, due to the high cost associated with its usual raw material, such as edible vegetable oils, biodiesel is currently not economically viable. Therefore, it is necessary to reduce the final price of this fuel. One of the ways to reduce costs will be the use of cheaper raw materials in the production process, such as used oils or non-edible ones. One of the main features of these cheaper raw materials is their low quality com-pared to edible oils. This low quality is associated with a high content of free fatty acids (FFA) and/or water. The FFAs present in the raw material must be converted into bio-diesel, also known as fatty acid metal esters (Fatty Acid Methyl Esters: FAME) by a transesterification reaction. In the present study, the use of the choline hydroxide catalyst in the production of biodiesel through the transesterification reaction, in a waste cooking oil (WCO) with acid-ity manipulation, is evaluated. The influence of the main operation parameters: tempera-ture, molar ratio WCO/methanol, catalyst dosage and oleic acid (OA) incorporation for control of acidity, was studied using a response surface methodology based in a Box-Behnken Design (BBD), evaluating two main responses: FAME content and the yield of the reaction. The most relevant factors were the molar ratio between waste cooking oil and methanol, catalyst dosage and incorporation of oleic acid. For main responses: FAME content and yield. It was possible to define the ideal conditions that lead to the greatest possible FAME content and the highest possible yield. The optimal condition to obtain 85.4% FAME content and 73.7% of yield was estimated at 63ºC, molar ratio of 1:13, 1.5wt% of catalyst and 0.5wt% of OA incorporation.