Study on New Technique of Biodiesel Production and Its Value-increment from Chinese Tallow Kernel Oil
|School||Huazhong University of Science and Technology|
|Keywords||Chinese kernel oil Fusel oil Biodiesel Dimmer Polyamide hardener|
Biodiesel, a typical "green energy", is a promising alternative for petroleum diesel. Biodiesel has many advantages, such as low content of sulfur and aroma hydrocarbon, high content of oxygen, high value of cetane number, flash point and ignition, less emission of hazardous exhaustion gases. At present, the main obstacles for biodiesel industrialization in our country are lacking of feedstock oil and high production cost. In the present study, enzymatic transesterification of biodiesel production was investigated from Chinese kernel oil and fusel oil as acyl acceptor in solvent-free and tert-butanol system, respectively. Furthermore, a new technology was employed to product dimmer acid from Chinese kernel oil biodiesel. Finally, optimization of parameters, like amid/acid ratio, reaction time and temperature, for polyamide resin preparation were conducted from dimmer acid. The characteristics of polyamide resin hardener were analyzed using DSC, IR, heat resistance tests and machnical property tests. Main experimental results were as follows:(1) Physic-chemical characteristics and fatty acid compositions of Chinese kernel oil were determined by gas chromatography-mass spectrometry (GC-MS) and thin layer chromatography (TLC) methods. The results showed that neutral lipid was the major composition, accounting for 99%. Meanwhile, the oil included a little glycolipids and phospholipids, accounting for 0.22% and 0.99%, respectively. There were 6 kinds of triglycerides in the feedstock oil, with 92% unsaturated triglycerides. The compositions of fatty acid were different for neutral lipid, glycolipids and phopholipids, respectively, but the main fatty acid composes of 18 carbons. 1.1-cis- dodecane acid and heptadecanoic acid were found in Chinese kernel oil, which were rarely found in natural oils and fats.(2) Enzymatic transesterification of biodiesel production was conducted from Chinese kernel oil and fusel oil in solvent-free and tert-butanol systems, respectively. The results showed that the maximal conversion rate of biodiesel was up to 98.3% and 76.3% from Chinese kernel oil and fusel oil catalyzed by combined lipases of Novozym 435 and Lipozyme TLIM in the solvent-free and tert-butanol system,, respectively. The effect of ratio of Novozym 435 to Lipozyme TLIM on biodiesel yield was significant and the optimal ratio of Novozym 435 to Lipozyme TLIM was 2:4.(3) The operational parameters, such as reaction temperature, reaction time and the ratio of urea to esters, cooling temperature, were optimized in the present work. The results showed that the optimum conditions were: reaction temperature 4°C, the ratio of fatty acid methyl ester to urea 1:1.5, reaction time15h and cooling at room temperature. The unsaturated fatty acid methyl ester with purity of 88% and total yield of 54.27% was obtained under the optimum conditions. The method employed in our work could be used in other feedstock oils to enrich unsaturated fatty acid. For example, the unsaturated fatty acid methyl ester of Chinese kernel oil, tung oil and tea oil respectively increase by 21%, 48% and 104% under the optimum conditions.(4) The operational parameters, such as reaction temperature, reaction time and dosage of catalyst, were optimized in the present work. The results showed that the optimum conditions were: bentonite dosage 12%, LiCl dosage 5%, reaction temperature 220°C and reactione time 6h. The dimmer acid yield of 75.2% was obtained under these optimum conditions.(5) The polyamide hardener was prepared from Chinese kernel oil. Differential scanning calorimetry (DSC), heat resistance tests and mechanical property tests were used to determine the appropriate weight ratio of this kind of polyamide and epoxy resin curing system. The results indicated that the optimum weight ratio of the curing system of polyamide to epoxy resin was 0.6:1.0. The curing reaction was completed most thoroughly under the optimum curing system. The characteristics of the product of polyamide and epoxy resin were analyzed in this work, and the results suggested that the heat resistance of the system was the highest and the resistantabilities of the impact, bending and shearing were the strongest. It was concluded that the characteristics of the fine chemical products from Chinese kernel oil was satisfactory.