Research On The Separation Technology Of Fatty Acid Produced By Soybean Oil Foots

Soybean oil foots is the by-product in the process of preparation of Soybean oil.It contains lecithin,neutral oil etc.It can be utilized to prepare fatty acids,which is wildly used in daily chemical industry,medical industry,and plastic industry etc.In this word,the methods of vacuum distillation and low temperature crystallization are used to separating the fatty acids which is prepared by Soybean oil foots,in order to obtain the unsaturated fatty acids product.Firstly the method of vacuum distillation was used.The operating conditions of the column were;operating pressure is 90Pa,the diameter of the column is 25mm,the height of tower is 3m,the filler used is Dixon ring(2×2,316L stainless steel),and the operation mode is batch distillation.But after many works on this process,none product can be obtained by this process,because the unsaturated fatty acid will get bad seriously in this process due to the high temperature in tower.Then the methods of low temperature crystallization was used.methanol,ethanol and n-hexane were used as the solvent of fatty acids,and the crystallization mode is gradient low temperature crystallization:the solution will firstly crystallize 5 ?,at then at 0? and-5 ? respectively.Then the solvent was vaporized from filtrate and finally the product was obtained.N-hexane was a better solvent compared anther two solvents.By a series of single factor experiments,the optimum amount of n-hexane is 2 times than the mass of raw fatty acids.By this solvent,finally the unsaturated fatty acids product was obtained,the content of unsaturated fatty acids in the product can be 96.4%,the yield can reach to 70.3%,And the reusing of precipitate that was produced in the process of low temperature crystallization was also researched.The scheme is:make the precipitate dissolved by a certain amount of solvent(same as the solvent used before)again and then make it crushed in 5 ?,the filtrate can be added to the previous separating process,the filter residue is the product that is rich in saturated fatty acids after vaporizing the solvent.