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Concentration of α-Linoleic Acid of Perilla Oil by gradient cooling Urea Inclusion

Agricultural Sciences in China 2009年第6期8卷 685-690页

作者： GU Hai-bo MA Xue-yi WU Jing-bo ZHANG Qi YUAN Wen-bing CHEN Yi-ping Key Study Center of the National Ministry of Education for Tropical Resources Utilization/Hainan Provincial Key Labortary of Fine Chemistry Haikou 570228 P.R. China State Key Laboratory of Applied Organic Chemistry Lanzhou University Lanzhou 730000 P.R.China Department of Chemistry and Chemical Engineering Jiangsu University Zhenjiang 212013 P.R.China

In this study, production of ct-linoleic acid concentrated from crude perilla oil by gradient cooling urea inclusion was optimized. The fatty acid composition was determined after ethyl esterification by gas chromatography （GC）. In this process, orthogonal experiment was carried out. Under optimum conditions, the maximum amount of α-linoleic acid （91.5%） was obtained at a urea to fatty acid ratio of 3, a solvent to fatty acids ratio of 7, a reaction temperature of 348 K and a crystallization time of 690 min. A simple method of gradient cooling urea inclusion was used to purify α-linolenic acid by using urea to form inclusion complexes with the saturated and the less unsaturated fatty acids, which enhanced the purity of α-linoleic acid ethyl ester by above 90%.

关键词： gradient cooling α-linoleic acid urea inclusion fatty acid perilla oil

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Numerical simulation on gradient cooling behavior of jumbo slab ingot

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China Foundry 2013年第2期10卷 87-91页

作者： Lü Nan Jin Yonglong Li Shengli Ai Xingang Yuan Xiaoguang School of Materials and Metallurgy University of Science and Technology Liaoning Tangshan Iron and Steel Group Corporation Shenyang University of Technology

Shrinkage porosity defect is often found in an air cooled jumbo steel ingot, which will influence the quality of the final rolled plates. In practical production, some rolled plates are frequently rejected due to the serious shrinkage porosity of the ingot. To improve the quality of the ingot, a new cooling method, gradient cooling process （in which the upper part of the ingot is air cooled and the lower part is spray cooled） was put forward in this study. The solidification behaviors for a 60 t jumbo slab ingot under gradient cooling condition were simulated using the ProCast software, and the results were compared with those of an ingot by air cooling condition. The solidifying tendency, temperature field and distribution of shrinkage porosities in the ingot under different cooling conditions were analyzed. Simulation results show that under gradient cooling condition the solidification of the slab ingot progresses in an upward manner along the vertical z axis and in a centripetal manner along the horizontal x and y axes. gradient cooling can efficiently reduce shrinkage porosity of the jumbo slab ingot by optimizing the solidification sequence, and making the position of shrinkage porosity move from near the middle height of the ingot （under air cooling condition） towards the head of the ingot; and the secondary shrinkage is eliminated. In addition, the solidification time of the ingot under gradient cooling is 7.3 h in this simulation, which is 2.7 h faster than that under air cooling. A 60 t jumbo slab ingot was successfully produced under gradient cooling condition. The ingot was rolled to a plate with a thickness of 100 mm and length of 18,000 mm, and ultrasonic flaw detection was performed. Some porosity was found along the axis of the plate at 4,900 position of the defect is moved towards the head with the simulated result. - 6,000 mm from the head of the plate, indicating that the of the ingot. This distribution trend of the defect is consistent

关键词： gradient cooling slab ingot temperature field shrinkage numerical simulation

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