Dynamic analysis and simulation on continuous flow processing of biodiesel production in single-mode microwave cavity

Abstract

A comprehensive physics-based model is developed to understand and explain the process of continuous production of biodiesel via the application of microwaves. Microwave assisted biodiesel production is a complex interplay of electromagnetics, reaction between different components and heat and mass transfer in a tube for continuous manufacturing. The multiphysics model is based on a single mode cavity operating at 2450 MHz. Material properties required for multiphysics modeling are assumed as bivariate functions of reaction solution's component and temperature in this work. An elaborate experimental system was developed to validate the multiphysics model through temperature measurements carried out for different initial velocities of the reacting components. Excellent agreement was found between experimental values and model predictions with a maximum relative error of 0.908%. The model developed is elaborate from the point of view of physics which can explain the process of microwave-assisted production of biodiesel and it's very important for optimize the process before scaling up. Also, due to fluid flow, presence of hot spots and thermal runaway caused by the short penetration depth of the microwaves and relative long term microwave heating can be done away with especially for large scale.

Continuous-Flow Microwave Reactor for High-Performance Heating of a Dynamic Chemical Reaction System

“…The chemicals used for the esterification reaction were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. The relative permittivity of chemical reactions is expressed as follows: , where and are the real and imaginary parts of the relative permittivity at temperature T 0 , and α′( C ), α″( C ), β′( C ), and β″( C ) are the functions of a reactant concentration.…”

“…Biodiesel can be produced by oleic acid and methanol as the main reactants via a typical esterification reaction. The reaction can be expressed as follows: 31,32…”

“…Biodiesel can be produced by oleic acid and methanol as the main reactants via a typical esterification reaction. The reaction can be expressed as follows: , The chemical reaction kinetic equation for biodiesel synthesis can be described as where and are the initial concentrations of oleic acid and methanol, respectively. denotes the concentration of water, k 1 indicates the forward reaction rate constant, and k –1 is the reverse reaction rate constant.…”

“…Biodiesel can be produced by oleic acid and methanol as the main reactants via a typical esterification reaction. The reaction can be expressed as follows: , RCOOH + normalC normalH 3 OH ↔ RCOOC normalH 3 + normalH 2 normalO The chemical reaction kinetic equation for biodiesel synthesis can be described as − normald ( C RCOOH 0 − C normalH 2 O ) normald t = k 1 ( C RCOOH 0 − C normalH 2 O ) ( C C normalH 3 OH 0 − C normalH 2 O ) − k − 1 C H 2 normalO 2 where C RCOOH 0 and C CH 3 OH 0 are the initial concentrations of oleic acid and methanol, respectively. C H 2 normalO denotes the concentration of water, k 1 indicates the forward reaction rate constant, and k –1 is the reverse reaction rate constant.…”

A Temperature-Control System for Continuous-Flow Microwave Heating Using a Magnetron as Microwave Source

“…By slowly turning the knob, the metal can be moved forward or backward slowly. In the experiment, after the reactant is filled with quartz tube, by moving the metal wall from left end (right outer wall of quartz tube) to right end and reading the reflect power from the power meter at the same time, a minimal reflect power can be detected and the metal wall in this position, which can make the electromagnetic energy density of the standing wave in the reaction pipe to be maximal, will be used throughout the heating process [24].…”