Kinetic Modeling Studies of Heterogeneously Catalyzed Biodiesel Synthesis Reactions

Efficient and Stable Rice Husk Bioderived Silica Supported Cu2S-FeS for One Pot Esterification and Transesterification of a Malaysian Palm Fatty Acid Distillate

A novel heterogeneous catalyst composite (CuS-FeS/SiO2) derived from rice husk silica was engineered following pyrolysis, chemical precipitation, and chemical redox technique. The resulting catalyst was applied to the conversion of palm fatty acid distillate to biodiesel. The presence of CuS and FeS on the catalyst was verified using X-ray diffraction and Fourier transform infrared spectroscopy, nitrogen physisorption, scanning electron microscopy (FESEM) with energy dispersive X-ray (EDS) spectroscopy, and temperature-programmed desorption of NH3 (TPD-NH3), inductively coupled plasma-atomic emission spectrometry (ICP-AES), and TGA; a specific surface area of approximately 40 m2·g−1 was identified. The impact of independent variables, i.e., reaction temperature, reaction duration, methanol:oil ratio and catalyst concentration were evaluated with respect to the efficacy of the esterification reaction. The greatest efficiency of 98% with a high productivity rate of 2639.92 µmol·g−1·min−1 with k of 4.03 × 10−6 mole·S−1 was achieved with the following parameters: temperature, 70 °C; duration, 180 min; catalyst loading, 2 wt.%; and methanol to oil ratio, 15:1. The CuS-FeS/SiO2 catalyst showed relatively high stability indicated by its ability to be reused up to five times.

Reaction rate law model and reaction mechanism covering effect of plasma role on the transesterification of triglyceride and methanol to biodiesel over a continuous flow hybrid catalytic-plasma reactor

This study investigated predictions of reaction mechanisms and reaction rate law model covering effect of plasma role on the heterogeneous catalytic reaction of triglyceride and methanol to produce biodiesel (fatty acid methyl ester - FAME or fatty acid alkyl ester – FAAE) over a continuous flow hybrid catalytic-plasma reactor. This catalytic reaction was carried out in a dielectric-barrier discharge plasma reactor over 5 wt% K₂O/CaO–ZnO catalyst under conditions of atmospheric pressure and the reactor temperature of 65 °C. During the hybrid catalytic-plasma reaction system, the voltage, the catalyst diameter, and the Weight Hourly Space Velocity (WHSV) were kept constant at 5 kV, 5 mm, and 1.186/min, respectively. It was found that transesterification reaction with the hybrid roles of catalytic and plasma achieved 77.2% biodiesel yield. Kinetic studies of this transesterification reaction over a continuous flow hybrid catalytic-plasma reactor suggested following Eley-Rideal mechanism model, where the methanol adsorbed on the catalyst surface reacted with triglycerides in bulk phase to produce an adsorbed methyl ester and glycerol in bulk phase. The possible reaction rate law model found is: -r_TG = r_ME = r_s = (0.0078∗(0.0061∗C_TG∗C_M³–3.0302 × 10⁻⁶∗C_ME³∗C_G))/(0.1827∗C_M+ 0.0145∗C_ME+1)³ gmol/gcat.min. This reaction rate law model was useful to design reactor of the hybrid catalytic-plasma chemical reaction system for biodiesel production.

Ultrasound-assisted biodiesel production using heterogeneous base catalyst and mixed non-edible oils

In the present study, the ultrasound-assisted biodiesel production from mixed feedstock of non-edible oils in presence of KI impregnated ZnO as a catalyst in batch reactor was investigated. The production was optimized by using two approaches (1) feedstock optimization and (2) process parameters optimization. Various non-edible oils at optimum volumetric ratio were blended and used as feedstock for transesterification reaction. Biodiesel yield was optimized by Box-Behnken statistical design. The maximum triglyceride conversion of 92.35 ± 1.08% was achieved at optimized conditions of catalyst loading = 7% (w/w); alcohol/oil molar ratio = 11.68:1 and reaction temperature = 59 °C. Transesterification process with mechanical agitation was used as base case for identification of role of sonication in the process. The transesterification process was analysed for kinetic behaviour using pseudo first order kinetics and Eley-Rideal mechanism based model. Overall activation energy of transesterification process for mechanically agitated and ultrasound-assisted systems was calculated as 135.4 and 123.65 kJ/mol, respectively. However, the sum of activation energies of three reaction steps of Eley-Rideal mechanism (64.69 kJ/mol and 46.63 kJ/mol, for mechanically agitated and ultrasound-assisted system, respectively) was much lower. This discrepancy is attributed to mass transfer limitations in the system, even in presence of sonication.

Lipase immobilised on silica monoliths as continuous-flow microreactors for triglyceride transesterification

Lipase immobilised on silica monoliths has been prepared and applied as biocatalytic continuous-flow microreactors for the transesterification of tributyrin as a model bio-oil component.

Kinetics of Transesterification of Safflower Oil to Obtain Biodiesel Using Heterogeneous Catalysis

The kinetics of the transesterification of safflower oil and methanol catalyzed by K2O/NaX was studied and modeled. The influence of the oil-methanol initial molar ratio and amount of catalyst were investigated to achieve a maximum triglycerides conversion (99 %) and a final methyl esters content of 94 % ±1. A kinetic model based on an Eley–Rideal mechanism was found to best fit the experimental data when assuming methanol adsorption as determining step. Other models derived from Langmuir – Hinshelwood – Hougen –Watson (LHHW) mechanisms were rejected based on statistical analysis, mechanistic considerations and physicochemical interpretation of the estimated parameters.

On the relationship between the basicity of a surface and its ability to catalyze transesterification in liquid and gas phases: the case of MgO

The influence of the basic properties of MgO is not the same for liquid and for gas phase transesterification.