Simulation of continuous catalytic conversion of glycerol into lactic acid in a microreactor system: A CFD study

Abstract

Hand in hand with the flourish of the biodiesel industry, glycerol (GLY) as an inconvenient by-product has generated environmental and sustainability concerns. Devising measures for efficient transformation of GLY into value-added products is a promising solution. In this contribution, the transformation of GLY to lactic acid (LA) as a valuable chemical was investigated in a continuous process for industrial applications. In this regard, a catalytic method using heterogeneous Cu nanoparticles in NaOH solution was studied in a microreactor by a CFD simulation. A seven-inlet micromixer comprising an optimized mixing unit was incorporated for uniform distribution of the species. The effects of various parameters upon the process performance were considered and the optimum points were determined. Also, the extent of the influence of each variable on LA yield was evaluated using sensitivity analysis techniques. While higher LA yield could be obtained at extreme scenarios, optimum values of the Re and temperature for obtaining the maximum performance under sensible operating conditions were determined to be 0.108 and 510.1 K which led to the optimum yields of 67.8% and 59.5%, respectively. Moreover, the sensitivity analysis revealed that the molar ratio of OH−/GLY and temperature were the most and least significant parameters, respectively.