Transesterification of canola oil as biodiesel over Na/Zr-SBA-15 catalysts: Effect of zirconium content

A series of mesoporous Zr-SBA-15-supported Na catalysts was prepared and applied to the heterogeneous catalysis of canola oil transesterification. The effects of Si/Zr ratio, reaction time, and percentage of Na loading on the conversion to fatty acid methyl esters (FAME) were studied. The dependence of the textural structure and chemical properties of Zr-SBA-15 supports on Zr content was investigated using small-angle X-ray diffraction, Brunauer–Emmett–Teller analysis, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The results obtained from FTIR and TEM indicate that the incorporation of Zr atoms into the SBA-15 structure facilitated the formation of Brönsted acid sites and decreased the particle size of Na species. Catalysts with a higher Zr content enhanced the FAME yield. The optimum conditions determined were as follows: reaction temperature of 70 °C, 15 wt.% Na, reaction time of 6 h, and 12% catalyst content (wt.% oil) with a methanol/oil molar ratio of 6:1. The optimum conditions resulted in a FAME yield of up to 99%.     

Application of the factorial design of experiments to biodiesel production from lard

Synthesis of biodiesel from lard was carried out using potassium hydroxide as a catalyst. A 3² factorial design of experiments was used. The effects of agitation speed and catalyst concentration were studied. A regression model was obtained to predict the methyl ester concentration and adequately describe the experimental range studied.     

Tribological Characteristics of Calophyllum inophyllum–Based TMP (Trimethylolpropane) Ester as Energy-Saving and Biodegradable Lubricant

The purpose of this research is an experimental study of Calophyllum inophyllum (CI)-based trymethylolpropane (TMP) ester as an energy-saving and biodegradable lubricant and compare it with commercial lubricant and paraffin mineral oil using a four-ball tribometer. CI-based TMP ester is a renewable lubricant that is nonedible, biodegradable, and nontoxic and has net zero greenhouse gases. The TMP ester was produced from CI oil, which has high lubricity properties such as higher density, higher viscosity at both 40°C and 100°C and higher viscosity index (VI). Experiments were conducted during 3,600 s with constant load of 40 kg and constant sliding speed of 1,200 rpm at temperatures of 50, 60, 70, 80, 90, and 100°C for all three types of lubricant. The results show that CI TMP ester had the lowest coefficient of friction (COF) as well as lower consumption of energy at all test temperatures, but the worn surface roughness average (R_a) and wear scar diameter were higher compared to paraffin mineral oil and commercial lubricant. Before 80°C, CI TMP ester actually has a higher flash temperature parameter (FTP) than paraffin mineral oil and as the temperature increases, the FTP of TMP ester decreases. The worn surfaces of the stationary balls were analyzed by scanning electron microscopy (SEM) and results show that CI TMP ester has the highest wear compared to paraffin mineral oil and lowest wear compared to commercial lubricant. However, CI TMP ester is environmentally desired, competitive to commercial lubricant, and its use should be encouraged.     

Optimization of the activity of CaO/Al2O3 catalyst for biodiesel production using response surface methodology

In this work the response surface methodology (RSM) in conjunction with the central composite design (CCD) were used to optimize the activity of CaO/Al₂O₃ solid catalysts for the production of biodiesel. In order to measure the catalyst activity, we used palm oil as a representative raw material for the conversion to biodiesel. The biodiesel production was carried out in a batch laboratory scale reactor. The results showed that both the calcination temperature and the amount of calcium oxide loaded on the support had significant positive effects on the biodiesel yield. The maximum basicity and biodiesel yield obtained were about 194 μmol/g and 94%, respectively. Overall, the catalyst showed high performance at moderate operating conditions and its activity was maintained after two cycles.     

Intensification of biodiesel production from vegetable oils using ultrasonic-assisted process: Optimization and kinetic

Intensification of biodiesel production process using low frequency ultrasonic irradiation (20 kHz, 200 W) is elucidated in this study. Effects of five process variables in an ultrasonic-assisted reactor catalyzed by SrO through transesterification of vegetable oils are investigated. RSM was employed and the optimum conditions were at an ultrasonic pulse on of 9 s followed by 2 s of pulse off within a reaction time of 30.7 min. The optimum ultrasonic power was found to be 130 W using an oil amount of 52 g (R² = 0.97). The model was applicable to different types of oil with errors less than 10%. FFA content was responsible for the different yields obtained with different oils. Three steps of the transesterification process were measured to obtain the kinetic study. The results revealed that the reaction followed a second-order kinetic. The activation energies varied between 70.63 kJ/mol and 136.93 kJ/mol showing relatively high coefficient of determinations.     

Process Parameter Optimization in Jatropha Methyl Ester Yield Using Taguchi Technique

Among all alternate fuel sources available, the biodiesel of Jatropha curcas appears to be a potential fuel as it widely exists in Asia. The Jatropha methyl ester (JME) is produced by transesterification process. In the transesterification process, alkyl group of ester exchanges with that of an alcohol. This work focuses on optimizing various parameters like quantities of methanol, KOH, and stirrer speed, which influence high JME yield. Based on L₉ orthogonal array, experiments are conducted by using Taguchi technique. All the nine combinations of L₉ orthogonal array are experimentally done for extraction of JME, and then it is used for analysis in Taguchi technique. The analysis of maximum yield is done on the basis of “larger is better” signal to noise ratio (S/N ratio). The best combination in the L₉ orthogonal array is found to be methanol (110 ml), KOH (1.306 gm), and stirrer speed (1200 rpm). The influence of methanol, KOH, and stirrer speed on the yield is found by analysis of variance (ANOVA). Based on the results of ANOVA, it is found that the influence of methanol, KOH, and stirrer speed on the yield are obtained as 70.10%, 20.35%, and 5.78%, respectively.     

Nonlinear model predictive control of biodiesel production via transesterification of used vegetable oils

The economic performance of an industrial scale semi-batch reactor for biodiesel production via transesterification of used vegetable oils is investigated by simulation using nonlinear model predictive control (NMPC) technology. The objective is to produce biodiesel compliant to the biodiesel standards at the minimum costs. A first-principle model is formulated to describe the dynamics of the reactor mixture temperature and composition. The feed oil and mixture composition are characterized using a pseudo-component approach, and the thermodynamic properties are estimated from group contribution methods. The dynamic model is used by the NMPC framework to predict the optimal control profiles, where a multiple shooting based dynamic optimization problem is solved at every sampling time. Simulation results with the economic performance of an industrial scale semi-batch reactor are presented for control configurations manipulating the methanol feed flow rate and the heat duty.     

Synthesis and Characterization of Amorphous Nano‐Alumina Powders with High Surface Area for Biodiesel Production

Nano‐alumina powders containing yttrium oxide were synthesized via the sol‐gel method using aluminum chloride hexahydrate as catalyst precursor. Fourier transform infrared analysis showed the presence of Al‐O and Al‐O‐Al bands in the powder structure and X‐ray diffraction spectra proved that the alumina was in the amorphous phase. The amorphous nano‐alumina powders were shown to be mesoporous with a high surface area, and both spherical and slit‐shaped particles were found in the calcined powder. A high percentage of conversion of oil to biodiesel was obtained in the transesterification reaction and the synthesized nano‐alumina powders could be easily regenerated for further use. The amorphous nano‐alumina powder can thus be recommended for use as active catalyst in the transesterification reaction for biodiesel production on the industrial scale.     

Biodiesel production in a jet flow stirred reactor

The rate of biodiesel formation was assessed in a transesterification reactor stirred with a dual jet flow close loop. A blend of 85% of soybean and 15% of sunflower oil, methanol and NaOH were used to study the rate of conversion from vegetable oil to methyl esters. A 9 l cylindrical reactor with conical bottom discharge connected to two centrifugal pumps for fluid recirculation through dual opposite radial jet flows in its upper part was developed for the experiment. The system did not require a heating supply due that the frictional effect inside the recirculation hoses and nozzles produced self heating of the inlet fluid to the reactor. Four different diameters of ejector corresponding to initial Reynolds Number (Re) ranging between 1300 and 6470 were tested to assess the reactor heating profile along with the kinetics of biodiesel formation. Clear performance differences among ejector diameters and Reynolds Number values were observed showing that higher Re result in low relative conversion times along with higher final temperature in the reactor. For 98% of relative conversion to biodiesel, the ejector with Re = 6470 showed 88% reduction in transesterification time with respect to an ejector delivering a Re = 1300 and without requiring any external heat source.     

Optimization of conversion of waste rapeseed oil with high FFA to biodiesel using response surface methodology

In the present study, waste rapeseed oil with high free fatty acids (FFA) was used as feedstock for producing biodiesel. In the pretreatment step, FFA was reduced by distillation refining method. Then, biodiesel was produced by alkaline-catalyzed transesterification process, which was designed according to the 2⁴ full-factorial central composite design. The response surface methodology (RSM) was used to optimize the conditions for the maximum conversion to biodiesel and understand the significance and interaction of the factors affecting the biodiesel production. The results showed that catalyst concentration and reaction time were the limiting conditions and little variation in their value would alter the conversion. At the same time, there was a significant mutual interaction between catalyst concentration and reaction time.The biodiesel produced in the present experiment was analyzed by gas chromatography/mass spectrometry (GC/MS), which showed that it mainly contained six fatty acid methyl esters. In addition, the diesel indexes analysis showed that most of the fuel properties were in reasonable agreement with the 0# diesel standard of China (GB252-2000) and the biodiesel standard of America (ASTM D6751).