Microwave enhanced transesterification of soybean oil and waste cooking oil

• Main Authors: Yung-Hung Chang, 張永宏
• Other Authors: 蕭明謙
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/z5akmz

碩士 === 崑山科技大學 === 環境工程研究所 === 97 === The fossil fuels is limited, therefore, the development of renewable energy is imperative. Biodiesel is defined as the fatty acid methyl esters made by transesterification of a refined oil or waste cooking oil. In this study, the use of soybean oil and waste cooking oil as a reactant, through open and closed method to microwave transesterification reaction, the use of homogeneous and heterogeneous catalysis production biodiesel. In soybean oil as raw material, in an open microwave, the use of nano calcium oxide catalytic reaction, the optimum conditions was as follows: molar ratio of methanol to oil is 7:1 with CaO concentration of 3 wt% and reaction time for 1 hour. The conversion of soybean oil into biodiesel was achieved 96.63% for 1 hour. In closed microwave, oil and alcohols are not totally miscible, so their reaction takes place at the interface and it is a very slow process, therefore, used of two different ways to reaction, first, the use of ultrasonic to be a mixture, and the other was to added solvent. The used ultrasonic optimum conditions was as follows: molar ratio of methanol to oil is 6:1 with NaOH concentration of 1 wt% and reaction time for 2 minutes, conversion was reached 97.68%. Added co-solvents the optimum conditions was as follows: molar ratio of methanol to oil is 12:1 with NaOH concentration of 1 wt% and reaction time for 2 minutes, biodiesel conversion of 97.36%. In the presence results, whether open or closed microwave, the use of soybean oil as raw materials, biodiesel conversion are conformed the Taiwan CNS 15072 standard value of 96.5%. Waste cooking oil as raw materials, the use of two different ways to reaction, one of which is to added co-solvents, and the other is to added co-solvents and the use of ultrasound to promote mixed. Added co-solvents, the high acid value (4.36 mg KOH /g) of waste cooking oil can be reduced to less than 2 mg KOH/g by acid catalyzed reaction for 7.5 minutes reaction time. The second step by transesterification reaction with a total reaction time of 9 minutes, the biodiesel conversion reached 97.38%. Besides, added co-solvents and the use of ultrasound to promote mixed, the acid-catalyzed conditions was as follows: ultrasound after 1 minutes, molar ratio of methanol to oil is 9:1 with H2SO4 concentration of 1 wt% and microwave reaction temperature to 60 ℃, reaction time 5 minutes, the acid value of waste cooking oil decreased to 2 mg KOH/g, then, followed by alkali-catalyzed reaction, the reaction time to spend a total of 8 minutes, and biodiesel conversion up to 99.01%. Preparation of four different acidic ionic liquids under closed microwave and catalyze soybean oil with methanol for transesterification to product biodiesel. The results showed that microwave power at 300 W, soybean oil-methnaol molar ratio of 15:1, ionic liquid concentration of 4 wt%, reaction temperature at 150 ℃, reaction for 60 minutes, [SO3H-BMIM] [HSO4] with better catalytic activity, and biodiesel conversion rate of up to 97%. Transesterification reaction of the activation energy for the 18.21 kJ / mole, the product of ionic liquids with easy separation, has good stability, and friendly to the environment. In this study, soybean oil and waste cooking oil production biodiesel to conformed Taiwan CNS 15072 standard value of 96.5%. The microwave irradiation method is provides efficient reduce the reaction time, increase in conversion and reduced the energy consumption, to achieve of energy saving and carbon reduction.