Langmuir–Hinshelwood kinetic study for palm oil catalytic cracking over Al-MCM-41

Abstract

Palm oil catalytic cracking over a mesoporous aluminosilicate material (Al-MCM-41) containing 5 % alumina was studied in order to evaluate the Langmuir–Hinshelwood (LH) kinetic parameters. The Al-MCM-41 catalyst was prepared by the sol–gel technique and was characterized by X-ray diffraction and nitrogen adsorption techniques. The Brunauer–Emmett–Teller surface area of the catalyst was found to be 1,278 m²g⁻¹. A 400 mL stirred batch autoclave reactor was used for catalytic cracking of 100 g refined palm oil and 1 g catalyst at a reaction temperature ranging from 573 to 673 K. The pressure–time data at different reaction temperatures were analyzed statistically in order to minimize experimental errors in the recorded pressures, whereas the statistically predicted pressure data were used to calculate the kinetic parameters. It was found that the fitting quality of the statistical model data using the LH model is similar to that of the raw experimental data. However, the values of the predicted parameters are significantly different. The estimated activation energy from LH kinetics was found to be 87 and 112 kJ mol⁻¹ calculated from statistical model data and raw experimental data, respectively. The predicted parameters obtained from statistical model data are found to be more accurate as the influence of experimental error is minimized prior to data analysis.