Kinetics of glycerol dehydration-hydrogenation reaction in the vapor phase in a fixed bed down flow tubular reactor over a bi-functional Cu-Zn/MgO catalyst

Abstract

Kinetic models were developed for the vapor phase hydrogenolysis of glycerol in a fixed bed down flow tubular reactor over a highly stable bi-functional Cu-Zn/MgO catalyst. The kinetic experiments were conducted at atmospheric pressure, at different temperatures (200–220 °C), and contact time (W/FGo) (101.5–609 kgcat. h kmol−1), respectively. The Langmuir-Hinshelwood-Hougen-Watson (LHHW) and Eley-Rideal (ER) type kinetic models were tried considering a two-step glycerol dehydration-hydrogenation process. The model equations were solved in MATLAB by using the ode23 function and the kinetic parameters were optimized by using the genetic algorithm optimization technique. The activation energy for the dehydration and hydrogenation steps was found to be 57.73 ± 10 kJ/mol and 156.71 ± 10 kJ/mol from LHHW kinetic model and 82.6 ± 8.3 kJ/mol and 146.2 ± 3.9 kJ/mol from ER kinetic model, respectively. Results demonstrated that both the models were fitted very well with the experimental data generated. However, the parity plots of the simulated and experimental partial pressure of glycerol, acetol, and 1,2-PD suggested that ER model was more appropriate as compared to the LHHW model.