Thread Content
Research on the catalytic preparation of biodiesel using magnetic solid catalysts. Biodiesel is an environmentally friendly fuel that can replace mineral diesel; it has a very low sulfur content, low levels of aromatic hydrocarbons, a high oxygen content, a high cetane number, a high flash point, and produces less exhaust gas； The exhaust gases released after combustion contain low levels of particulate matter (PM), total hydrocarbons (HC), and carbon monoxide. Compared to other alternative fuels such as natural gas, liquefied petroleum gas, and ethanol, using biodiesel systems requires less investment; there is basically no need to make any changes to existing engines, fueling equipment, storage facilities, or maintenance equipment ； It can be used as fuel, or it can be mixed with diesel in any proportion as an additive. Supium sebiferum (I. ) Roxb is a plant of the genus Supium in the Euphorbiaceae family. It is a woody oil-bearing tree species unique to China, and due to its high oil content in the seeds, it is listed as one of China’s four major woody oil-bearing plants. It can serve as a source of edible oil as well as industrial oil, and it can also be used as a fuel oil. It boasts strong adaptability, good water resistance, and rapid growth; it is an inexhaustible renewable oil source with great potential for development, offering high economic and social benefits. It has been cultivated in our country for over 1,000 years, and records of the Chinese tallow tree can be found in the work written by Jia Sixie in 534 AD. Currently, the catalysts used in the conventional production of biodiesel are mostly homogeneous catalysts, typically NaOH, KOH, metal alkoxides, and concentrated H2SO4. The use of substances such as NaOH as catalysts is mainly due to their low cost and availability, but they have serious drawbacks: not only is the post-treatment process complex, but they also easily cause environmental pollution through waste generation ； As catalysts, enzymes have the disadvantages of being expensive, prone to deactivation, and requiring long reaction times. http://www.cqvip.com Issue 3: Chen Wenwei et al.: Research on the catalytic preparation of biodiesel using magnetic solid catalysts = === == === == === == === === === == === == === == === ===== === === ⋯ = === == === == ==: == === == : — — — — 1 Materials and Methods 1.1 Materials: Toona sinensis oil (from Dawu County, Hubei), anhydrous methanol, FeSO4·7H2O, Fe2(SO4)3·xH2O, Mg(NO3)2·6H2O, Al(NO3)3·9H2O, NaOH, Na2CO3, and H3PO4 (85%); all reagents were of analytical grade. 1.2 Main instruments and equipment: Agilent 6890N gas chromatograph (FID detector) ； HP—INNOWaX capillary column) ； Shanghai Yarong Rotary Evaporator RE52—98 ； TDL-15-A centrifuge ； FA2004N electronic balance. 1.3 Experimental Principle The raw Chinese toon oil contains certain amounts of free fatty acids and a very small amount of water; if methylation is carried out directly, the esterification rate is low. Therefore, it is necessary to remove these components first ； Then, the castor and catalpa oil was subjected to transesterification using a magnetic solid catalyst. CH2OOCR1 → CHOOCR2 + 3CH3OH → CH2COOR3; magnetic solid catalyst. CH2OH, CHOH + CH2OH; R1COOCH3, R2COOCH3, R3COOCH3. 1.4 Pretreatment of Euphorbia cerifera oil: The pretreatment of Euphorbia cerifera oil is carried out using a medium-temperature wet degumming process. A certain amount of crude oil is heated to 80E, then 0.1% H3PO4 is added and mixed with it. After that, 4% water at the same temperature is added; the mixture is stirred for a certain period of time before demulsification takes place. The mixture is then allowed to stand at a constant temperature, separated, and washed with water at 80E until it reaches a neutral pH. Finally, centrifugation is used for separation, resulting in the treated castor oil that is ready for use. 1.5 Preparation of magnetic solid catalysts: FeSO4·7H2O and Fe2(SO4)3·xH2O were added to distilled water in a 1:2 ratio and dissolved to form an aqueous solution. This solution was then poured into a round-bottom three-necked flask; the temperature was maintained at 65°C, and 20% ammonia water was added. After stirring, the mixture was allowed to stand for 60 minutes, resulting in an oil-black precipitate. The precipitate was washed repeatedly until it became neutral and free of SO4²⁻ ions, after which it was set aside for use. A certain amount of magnetic matrix is added to a round-bottomed three-necked flask, followed by the addition of second-distilled water, with vigorous stirring ； A certain amount of Mg(NO3)2·6H2O and AI(NO3)3·9H2O in a molar ratio of 3:1 was taken to prepare a nitrate salt solution ； An additional amount of NaOH and Na2CO3 was used to prepare a solution; these two solutions were then added drop by drop to the flask mentioned above. After all the drops had been added, the temperature was raised to 65°C, and stirring continued for 18 hours. The mixture was then filtered, and washed repeatedly until it reached neutrality. The resulting product was dried under vacuum at 80°C for 12 hours. Finally, the above samples were calcined in a muffle furnace (500Y3) for 10 hours to be converted into composite oxides, which served as the magnetic solid catalysts. 1.6 Process route and technology for the methylation of Elaeocarpus and Catalpa oils: Methanol, methanol recovery; water; magnetic solid catalyst; glycerol phase; tl, I, f (refined separately); bio-diesel. Figure 1 shows the process for the methylation of Elaeocarpus and Catalpa oils. A certain amount of pre-treated Elaeocarpus and Catalpa oil is placed in a 500 ml flask, heated to a specific temperature in a water bath, then methanol and the self-made magnetic solid catalyst are added, followed by stirring. Sampling is taken at regular intervals for gas chromatographic analysis. After the reaction is complete, it is cooled and separated into layers; the upper layer is taken for distillation and washing, and biodiesel fractions are obtained through vacuum distillation. VIP Information http://www.cqvip.com Fujian Forestry Science and Technology, Volume 33, 1.7 Analysis of Biodiesel Products: The contents of various fatty acid methyl esters in biodiesel were determined using capillary gas chromatography. The chromatography column is installed using a split-injection method. The column temperature is raised using a programmed heating profile: the initial temperature is 150°C, maintained for 1 minute; then it increases at a rate of 15°C per minute until reaching 225°C, after which it rises at a rate of 50°C per minute to the final temperature of 280°C, where it is maintained for 7 minutes ； Injector temperature 220°C ； Detector temperature 300°C ； Carrier gas N2. Methyl undecanoate is used as the internal standard, and the internal standard method is employed to quantify the content of methyl fatty acid esters in the oil of Elaeocarpus serratus. 2 Results and Discussion 2.1 Analysis of the castor-toon oil biodiesel product The fatty acid methyl ester pattern of the castor-toon oil biodiesel is shown in Figure 2. As can be seen from the figure, the main components of the Elaeocarpus serratus oil biodiesel are the methyl esters of fatty acids C16:0, C18:0, C18:1, C18:2, and C18:3. 2.2 Orthogonal experiment on the methylation of Elaeocarpus and Catalpa oil In this study, an orthogonal experiment with 4 factors and 3 levels was employed to optimize the conditions for the ester exchange reaction, thereby determining the optimal conditions for this reaction. Several values: 7, 75, 88, 59, 9.5; 10 minutes. Figure 2: Gas chromatogram of the methyl esters of fatty acids in the oil obtained from Elaeocarpus and Catalpa trees. 1. C16:0, 2. C18:0, 3. C18:1, 4. C18:2, 5. C18:3. Table 1: Results of the orthogonal experimental design regarding the factor ‘water’ F. * “- Po.01(2,8) = 8.65 ； Fo．o5(2,8)=4.46. Data analysis shows that factors D (reaction temperature), c (mole ratio of alcohol to oil), A (reaction time), and B (amount of magnetic solid catalyst) have a highly significant impact on the esterification rate of biodiesel. Based on the esterification rate, the optimal process conditions for producing biodiesel were determined to be A2B2CaD2: an alcohol-to-oil molar ratio of 10:1, a reaction temperature of 60°C, a dosage of 4.0% magnetic solid catalyst, and a reaction time of 2.5 hours. Thus, through the orthogonal experiment, the esterification rate under the optimized process was found to be 95.59%. Therefore, it is feasible to produce biodiesel using magnetic solid catalysts. Vip Information http://www.cqvip.com Issue 3 Chen Wenwei, et al.: Research on the Catalytic Preparation of Biodiesel Using Magnetic Solid Catalysts · 13 · 3 Conclusions 1) Biodiesel is an excellent alternative to mineral diesel. By developing the biodiesel industry and combining it with the restoration of forests through the use of Jatropha, a woody oil-bearing plant unique to China, biofuel raw material bases can be established. This approach can increase farmers’ incomes and improve their living standards, while also promoting economic and social development in rural areas and surrounding regions, thus playing an important role in revitalizing agriculture ； It can also reduce environmental pollution and make an important contribution to China’s oil security. 2) The preparation of biodiesel using magnetic solid catalysts is successful and feasible. Magnetic solid catalysts are efficient and environmentally friendly catalytic materials; they consist of a magnetic matrix supported on a solid catalyst, endowing them with dual functions – both magnetic properties and basic catalytic properties. This catalyst possesses high catalytic activity ； It can be easily separated and recovered from the reaction system, and possesses renewability ； It is environmentally friendly and does not cause corrosion to the reaction equipment. 3) The main components of the biodiesel prepared from the oil of Elaeocarpus and Catalpa are methyl fatty acid esters of C16:0, C18:0, C18:1, C18:2, and C18:3 ； Meets biodiesel requirements. 4) Optimal process conditions: alcohol-to-oil molar ratio of 10:1, reaction temperature of 60°C, amount of magnetic solid catalyst used at 4.0%, and reaction time of 2.5 hours ； The esterification rate is 95.59%.