جستجوی مقالات مرتبط با کلیدواژه « ترانس استریفیکاسیون » در نشریات گروه « مکانیک »

Due to the increasing environmental pollution and the reduction of fossil fuel resources, the choice of a suitable alternative for non-renewable fuels has been given much attention. Among several alternative fuels, biodiesel is also clean and is produced from renewable sources. In this work, the mathematical modelling and optimization of the catalytic transesterification process for producing soybean oil biodiesel by MATLAB software and differential evolution algorithm has been investigated. The potassium hydroxide was selected as a homogenous catalyst for transesterification reactions in a batch reactor. Based on the experimental data, a model has been proposed to predict the biodiesel production in the catalyst concentration range of (0.4-1wt%), methanol to oil molar ratio range of (5-12) and temperature range of (25-65 °C). In addition, the unknown kinetic parameters of this model have been calculated. There was a good consistency between the model and experimental data. The modeling results showed that there is a relationship between biodiesel yield and effective parameters (temperature, oil to alcohol molar ratio and catalyst concentration). By increasing the temperature and oil to alcohol molar ratio and decreasing the catalyst concentration, the yield of biodiesel increases. Finally, the model was assisted to find the optimal conditions of transesterification reaction to maximize biodiesel yield. In the optimal conditions (catalyst concentration of 0.4501 wt%, molar ratio of methanol to oil of 15 and temperature of 70°C) the biodiesel yield reached 96.87%.

In recent years, due to the favorable climate conditions of Iran, rapeseed cultivation has increased significantly. Iran's canola production was 145,900 tons per year in 2010, which reached 174,999 tons per year in 2013. The purpose of this study was to investigate the possibility of biodiesel production from non-edible rapeseed oil using ultrasonic device. In this research, four different factors such as molar ratio, reaction time, pulse and amplitude were considered at three levels. Statistical analysis using Designe Exeprt software, response surface method (RSM) and Box Behnken layout was used to identify the optimal conditions of the process. After analyzing the data and optimizing the biodiesel production process, the biodiesel yield was 89.26% under the optimized conditions, i.e., a methanol-to-oil molar ratio of 4.87:1, pulse of 0.99 s, amplitude 73.5%, and a reaction time of 3.77 min. The biodiesel prepared from None-edible rapeseed oil complies with the criteria dictated by EN 14112 standards. So, the produced biodiesel from none-edible rapeseed can be used as an alternative fuel for a diesel engine.

In this study, the effective parameters on the amount of biodiesel production from date seed oil via three heating methods of conventional, microwave, and ultrasonic were assessed. In order to carry out the biodiesel production process, the esterification reaction using sulfuric acid as catalyst was firstly performed to reduce the free fatty acid content of date seed oil to the standard amount for transesterification reaction. The results showed that 1 wt.% of catalyst and 8-9 molar ratios of methanol to oil were the optimum amount for all of biodiesel production methods. In other words, utilized method has no effect on the amount of catalyst and methanol in the reaction. The temperature of 56 °C was selected as an optimum temperature in the conventional heating method and the power of around 300 W provided the highest yield in both microwave and ultrasonic methods. However, the major different was in the reduction of reaction time. It decreased from 90 min for conventional method to equilibrium point 7.5 and 3 min for ultrasonic and microwave methods, respectively. According to energy consumption, microwave method was known more suitable than ultrasonic method. The results of modeling presented that suggested models were in good agreement with the experimental values. Methanol/oil molar ratio and reaction temperature in the conventional method, amount of catalyst and methanol in the microwave method and power of ultrasonic waves in the ultrasonic method had the highest influence on the conversion of date seed oil to biodiesel.

The purpose of the present study is to produce biodiesel from fish waste oil and methanol by combination of mechanical stirrer and microwave as a technique to accelerate this. In this research, a microwave system was used including microwave source, stirrer, spiral tube and decantor. With the help of this system, the effect of molar ratio of alcohol to oil (4 to 1, 6 to 1 and 8 to 1), catalyst concentration (0.5, 1 and 1.5 weight percent of oil), reaction time (5, 15 and 25 min) and microwave time (0.5, 1.5 and 2.5 min) on the conversion of fatty acid to methyl ester. For analyzing the obtained results, the response surface method and Box Behnken layout were used in Design Expert 10.0 software. After analyzing the data and optimizing the biodiesel production reaction, it was found that the highest percentage of biodiesel conversion (92.62%) was found in the catalyst concentration of 1.13%, the reaction time of 24.61, the molar ratio of alcohol to oil of 5.55 and the microwave time of 0.5 minute. The regression model between independent variables and dependent variable (percent conversion) was obtained as a quadratic equation with R2 = 0.9953.

Biodiesel, due to its environmental benefits and similar properties with diesel, is considered as a fossil fuel alternative. Rapeseed oil is used to produce biodiesel in presence of K2CO3/Al2O3. For catalyst preparation K2CO3 was loaded on the Al2O3 as support using impregnation. Taguchi’s experimental setup was used in a completely randomized design with two replications for transesterification reaction and investigating the effects of reaction time, temperature and catalyst concentration on biodiesel production efficiency and to optimize the number of experiments. Also, molar ratio of 15 to 1 (alcohol:oil), catalyst concentrations of 0.5, 1, 1.5, 2, 3 and 5 wt.%, reaction temperatures of 55, 65 and 75 °C, reaction times of 0.5, 1, 1.5, 2, 2.5 and 3 hr. and stirring rate of 600 rpm was used for transesterification reaction. Highest biodiesel yield (99%) was obtained by transesterification process at 65 °C using 2 wt. % of K2CO3/Al2O3 for 2 hr. Comparing these results to other researcher’s results shows that the loading ratio of K2CO3 compared to KNO3 and Ca(NO3)2 can increase the biodiesel production efficiency in alumina-based catalysts. Analysis of variance analysis with regard to catalyst, reaction time and temperature variables indicates that temperature changes have no significant effect on the efficiency of methyl ester production, but the effects of time and catalyst concentration on the reaction rate is quite significant.

In recent years, coinciding with the expansion of biofuel production, attempts have also been made to optimize production processes. In this study, Response Surface Methodology (RSM) was used to investigation the transesterification reaction of rapeseed oil for biodiesel production. Three main factors in order to convert triglycerides into fatty acid methyl esters (FAME) were applied according to a central composite design. These factors were catalyst concentration (NaOH), reaction temperature and time. The yield of methyl ester as the first response was determined using NMR method. The second response was the commercial cost of production. The results showed that the best conditions for producing biodiesel in constant the molar ratio of 1: 6 oil: methanol were the temperature of 47.27 oC, NaOH concentration of 1.24 %wt/wt and reaction time of 30 min. At these optimum conditions, the yield of methyl ester and cost of production is 77.67% and 67 ¢, respectively. Also, some chemical and physical properties of biodiesel were compared with petro-diesel fuel. According to the results, biodiesel fuel is a suitable substitute for petro-diesel fuel.

In this research, biodiesel was initially produced from waste vegetable oil by transesterification reaction. The main properties of this fuel were compared with the ASTM D-6751 standard.then, performance of MF-399 tractor engine was tested and evaluated by using 5 to 25 percent biodiesel and diesel blends. Test results showed that, the power and torque of MF-399 tractor engine were increased, using biodiesel and diesel blends. This is because of good combustion of biodiesel due to high oxygen content of this fuel. There was also a slight increase in the fuel consumption and specific fuel consumption of biodiesel and diesel blends due to low calorific value of biodiesel. Results show that the B5D95 blend has the best performance and the lowest increase in specific fuel consumption among the other blends. The fuel consumption and specific fuel consumption of B25D75 was lower than the B20D80 blend. Therefore, if the goal is using high amount of biodiesel, B25D75 blend is recommended for use in MF-399 tractor engine.