Preliminary Research On Vacuum Batch Distillation Of C18 Fatty Acid Methyl Esters

There are lots of valuable fatty acid esters,which are important to our daily life,in the lipids of plant,animal and waste cooking oil.Not only are these fatty acid esters able to be used for preparing the biodiesel which can meet our growing demand of fossil fuels and energy,but also they play an irreplaceable role in many fields,such as daily chemical industry,medicine and health products.Due to the special application of fatty acid esters with specific structure,obtaining the high content/pure fatty acid esters is the research hotspot and difficulty in the field of the separation and purification of functional lipids.To explore and study the effect of high vacuum batch distillation on the separation of C18 fatty acids esters,the oil which is rich in stearic acid,oleic acid and linoleic acid is employed as the raw material.In the meantime,a simple and convenient method of the extractant-screening for high vacuum extraction batch distillation(HVED)has been put forward and introduced.Based on the mentioned above,the contents of this research mean a lot to the separation of fatty acids and provide a new way to purify the substances,which are thermo-sensitive or similar in the physical characteristics as well.A comprehensive analysis and study of the raw material's physicochemical properties has been done in this paper.The fatty glyceride with high boiling temperature in the palm oil was transformed into fatty acid methyl ester catalyzed by CaO in order that the process of distillation can be achieved efficiently and the content of the fatty acids was able to be analyzed easily.Besides,the content of the crude oil and products can be determined by the method combining the GC with GC-MS and NMR.On account of those,the whole process of this research can be accepted as an accurate and reliable work.Then,the reflux and condenser pressure of the process of high vacuum batch distillation have been investigated and the changing trend of the content of the C18 has been analyzed simultaneously.Upon completion of the first distillation,the separation process can result in producing the mixture of the methyl oleate and methyl linoleate with the content of 98% and the recovery of 15%~50%.As for the each content of the methyl esters,the content of methyl oleate and methyl linoleate were around 85% and 13% respectively.Subsequently,the first distillation products were separated by the batch distillation column as the second distillation raw material.The content of methyl oleate in the distillate can reach around 92% and the substances remaining in the bottom mainly consist of the methyl stearate and methyl oleate.Moreover,the process of the high vacuum distillation was simulated by Aspen Plus 8.8 and the parameters of the methyl esters were estimated with the assistance of that.The data of the simulation of the high vacuum batch match well with those of the experiments.Additionally,the effects of reflux,condenser pressure and other 3 factors on the content of the methyl esters in the distillate of the continuous rectification were investigated by the Aspen Plus.The appropriate operating conditions of this high vacuum continuous rectification were obtained.Based on the optimized conditions mentioned above,the content of methyl oleate can reach above 90%.In order to improve the degree of separation of mixture,the extraction distillation and the COSMO-SAC model utilized to select proper extraction agents were proposed by this research.Meanwhile,the extraction performance of reagents simulated by Aspen Plus were also used to prove the feasibility of employing that model so that ionic liquids can be chosen suitably as the extraction agents of the high vacuum distillation in the near future.