Biodiesel Production by Reactive Flash: A Numerical Simulation

Alejandro Regalado-Méndez,Reyna Natividad,Rubí Romero,Sigurd Skogestad

doi:10.1155/2016/7843081

Abstract

Reactive flash (RF) in biodiesel production has been studied in order to investigate steady-state multiplicities, singularities, and effect of biodiesel quality when the RF system approaches to bubble point. The RF was modeled by an index-2 system of differential algebraic equations, the vapor split (ϕ) was computed by modified Rachford-Rice equation and modified Raoult’s law computed bubble point, and the continuation analysis was tracked on MATCONT. Results of this study show the existence of turning points, leading to a unique bubble point manifold,(xBiodiesel,T)=(0.46,478.41 K), which is a globally stable flashing operation. Also, the results of the simulation in MATLAB® of the dynamic behavior of the RF show that conversion of triglycerides reaches 97% for a residence time of 5.8 minutes and a methanol to triglyceride molar flow ratio of 5 : 1.

Highlights

In the last decade, biofuels production has been worldwide motivated by the need of reducing greenhouse gases in order to slow down climate change
The set of differential algebraic equations (DAEs) system is conformed by 8 differential equations and 12 algebraic constraints, which come from mass and energy balances and thermodynamic considerations, respectively
The index-2 system of DAEs was solved by using ode15i MATLAB toolbox when Q = −100 K mol−1

Summary

Introduction

Biofuels production has been worldwide motivated by the need of reducing greenhouse gases in order to slow down climate change. Biofuels production has been encouraged by the unstable oil prices, the reduction of petroleum reserves, and environmental penalties in stationary and mobile sources of pollution. In this context, biodiesel emerges as a viable renewable energy alternative to petroleum diesel. RD have many advantages, which include reduced capital cost, complete conversion in equilibrium-limited reactions, heat integration, and reduced waste generation [3, 4] This makes of RD a rather complex hybrid process because of the interactions between reaction and phase equilibrium.

Methods

Results

Conclusion