Design and analysis of agitator types in a pressurized batch reactor for in-situ transesterification

• Main Author: Chiu, Glenn Matthew K.
• Format: text
• Language: English
• Published: Animo Repository 2018
• Subjects: Chemical reactors; Mixing machinery; Esterification; Materials Science and Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/7021
• Institution: De La Salle University

Subcritical in-situ transesterification (SCW-ISTE) is one of the more recently developed processes that consumes less energy and is more environmental friendly than conventional methods. Diving deeper into this process, the fluid dynamics of the liquid mixture is an area of interest not studied before due to the solid, thick metal enclosure of the reactor vessel. It was determined that the mixing characteristics of the agitator being used has shown to influence biodiesel yield based from literature review. As commercialization of this biofuel production process is of importance in order to contribute to biofuel demand in a nation-wide scale, this study considers a reactor vessel working volume of around 1.5L, which is relatively larger than typical laboratory batch- type sizes. This work will be accomplished using computational fluid dynamics software, where the study is divided into 3 parts. The first stage represents the initial condition of the system, where the biomass particles are the main reactants present in the fluid mixture. Stage 2 and 3 represent the stage wherein the lipids in the biomass have been fully extracted, and the system has already reached a 26.3% and 52.61% FAME conversion, respectively. Design of experiments (DOE) was implemented for this study, which follows a 2k full factorial design. Statistical analysis was performed to determine the most applicable agitator design for the SCW-ISTE process. The factors for the DOE are set to continuous and are the blade angle, disc diameter, and mixing speed. On the other hand, the fluid simulation result’s concentration and velocity profiles are the responses. Finally, the combinations of range for the agitator design factors that produces satisfactory mixing characteristics were determined from the simulated results. Although the blade angle and mixing speed only have statistically significant effects on Stage 2’s axial velocity, they are still seen to produce notable effects on the responses based on the numerical models’ results.