Biodiesel production in the presence of heterogeneous catalyst of alumina: Study of kinetics and thermodynamics

Abstract

In the current research, biodiesel production was investigated in the presence of solid catalysts of K 2 CO 3 /Al 2 O 3 by transesterification of rapeseed oil. The specifications of produced fatty acid methyl esters like viscosity and flash point were studied, and it was noted that they complied with the requirements of ASTM D6751. In addition, the kinetic and thermodynamic parameters were explored considering the temperature changes between 318.15 and 348.15 K. Mass transfer resistance (external diffusion or internal diffusion) over the catalyst was neglected with regard to theWeisz-Prater criterion and Mears criterion. The kinetic models containing Eley-Rideal, Langmuir-Hinshelwood, pseudo-first-order, pseudo-second-order, and -order models were investigated. Corrected Akaike information criterion was utilized to find the best model fitted with the experimental data. The greatest illustration for the K 2 CO 3 /Al 2 O 3 -catalyzed reaction was the nonlinear model with an order of = 1.287 and the activation energy of 12.12 kJ/mol. Using transition state theory (Eyring-Polanyi equation), the activation Gibbs free energy, activation enthalpy, and activation entropy were calculated at different temperatures. The equilibrium thermodynamic properties depicted that this process is endothermic and spontaneous toward biodiesel production and tends to be irreversible. K E Y W O R D Salumina, heterogeneous catalyst, kinetics, thermodynamic, transesterification 472

Advances in morphology-controlled alumina and its supported Pd catalysts: synthesis and applications

“…As mentioned above, the abundant surface sites and excellent thermal stability of alumina make it able to serve as a distinguished and versatile support for Pd nanoparticles. 28 The alumina-supported Pd catalysts are extensively employed in industrial-scale catalytic processes. The performance can be influenced by several factors, including morphology, composition, surface nature of the alumina support, the particle size, active phase, and surface structure of active metals, as well as the interaction between the active metals and supports and their corresponding catalytic microenvironment.…”

Study on Kinetics and Reaction Parameters of Biodiesel Production from Sunflower Oil and Methanol Using Zinc Oxide Supported Calcium Oxide

“…The numerous kinetic studies were performed to investigate reaction conditions and mechanisms in presence of heterogeneous catalysts [18][19][20][21][22]. Since the reaction proceeds in liquid phase with solid catalyst the reaction steps were consisted of adsorption, surface reaction desorption.…”

“…In this study, the following Eley-Rideal model was considered in order to investigate reaction mechanism where the surface reaction was rate-limiting step [19][20][21].…”

“…The kinetics of transesterification by using heterogeneous catalysts were generally investigated as pseudo-order reaction with considering overall reaction because of excessive methanol concentration assumed unchanged during the reaction [18]. Eley-Rideal and Langmuir-Hinshelwood models were also investigated by researchers [19][20][21] as like other heterogeneously catalyzed reactions which involves three familiar steps (adsorption, surface reaction and desorption). The five different kinetic models were investigated by Gholipour Zanjani et al [20].…”

“…Eley-Rideal and Langmuir-Hinshelwood models were also investigated by researchers [19][20][21] as like other heterogeneously catalyzed reactions which involves three familiar steps (adsorption, surface reaction and desorption). The five different kinetic models were investigated by Gholipour Zanjani et al [20]. In their study, nonlinear α-order kinetic model with respect to triglyceride found better than pseudo order, Eley-Rideal and Langmuir-Hinshelwood models for the transesterification of rapeseed oil with methanol by using K 2 CO 3 /Al 2 O 3 catalyst.…”