Advances on kinetics and thermodynamics of non-catalytic supercritical methanol transesterification of some vegetable oils to biodiesel
| Autor: | Nuria García-Martínez, Joaquín Quesada-Medina, María del Mar Durán-del-Amor, Pedro Andreo-Martínez |
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| Přispěvatelé: | Departamento de Ingeniería Química |
| Rok vydání: | 2018 |
| Předmět: |
Order of reaction
020209 energy Energy Engineering and Power Technology 02 engineering and technology chemistry.chemical_compound Reaction rate constant 020401 chemical engineering 0202 electrical engineering electronic engineering information engineering medicine 0204 chemical engineering Biodiesel Renewable Energy Sustainability and the Environment Chemistry Transesterification Supercritical fluid Supercritical methanol Kinetics Fuel Technology Nuclear Energy and Engineering Chemical engineering 66 - Ingeniería tecnología e industria química. Metalurgia [CDU] Castor oil Biodiesel production Thermodynamics Methanol Vegetable oils medicine.drug |
| Zdroj: | DIGITUM: Depósito Digital Institucional de la Universidad de Murcia Universidad de Murcia DIGITUM. Depósito Digital Institucional de la Universidad de Murcia instname |
| Popis: | © . This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the Accepted Manuscript version of a Published Work that appeared in final form in Energy Conversion and Management. To access the final edited and published work see https://doi.org/10.1016/j.enconman.2018.07.069. Kinetic and thermodynamic parameters of the non-catalytic supercritical methanol transesterification reaction of castor, jatropha, pongamia, tobacco, soybean and jojoba oils to biodiesel production were evaluated in the present study. The experiments were conducted in an 83 ml closed batch reactor at different temperatures (250–350 °C) and reaction times (15–90 min), and at optimal methanol-to-oil molar ratios (15:1 in the case of jojoba wax-oil and 43:1 for the rest of the oils). The pressure reached in the reactor ranged from 10 to 43 MPa. Integral method was used to determine appropriated reaction orders by an adjustment of experimental data to pseudo-zero, pseudo-first and pseudo-second order kinetic equations using Levenberg-Marquardt algorithm. Pseudo-first-order kinetic equation was found to be the most appropriate to describe the supercritical transesterification reaction of the vegetable oils studied. Rate constants and Arrhenius parameters were calculated, the activation energy followed the sequence: castor oil < jatropha oil < tobacco oil < pongamia oil < soybean oil < jojoba wax-oil. It is difficult to explain the behavior of jojoba and castor oils in relation to that of the rest of vegetable oils because they have a very different structure and fatty acid composition, respectively. However, the aforementioned sequence observed for the rest of vegetable oils (jatropha, tobacco, pongamia and soybean oils), which have a similar structure and fatty acid composition, can be attributed to the content of linolenic acid in the oil: the higher the content of linolenic acid, the higher the activation energy and the lower the reaction rate. Finally, thermodynamic study showed that the non-catalytic supercritical methanol transesterification reaction is non-spontaneous (endergonic) and endothermic in nature. |
| Databáze: | OpenAIRE |
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