Separation Of N-hexane-isopropanol Mixed System By Liquid-liquid Extraction

In this paper the properties and uses of n-hexane and IPA was reviewed, the difficulties in separating and purifying n-hexane-IPA mixed system was analyzed and the research status of separating n-hexane-IPA system at home and abroad was summarized. On the basis of the research above, the advantages and disadvantages of the extractive distillation method and liquid-liquid extraction method was compared and the method of liquid-liquid extraction was put forward to separate n-hexane-IPA mixed system. According to the principle of the selection of extraction agent and the combination of n-hexane and IPA dissolve characteristics, water was determined as liquid-liquid extraction agent through the analysis and comparison experiment.The extraction ability of water as extraction agent to separate n-hexane-IPA system from the perspective of thermodynamics was investigated. The determination conditions of liquid-liquid equilibrium data was optimized by the experiment. On this basis, the liquid-liquid equilibrium data of n-hexane - IPA - water ternary system at 20 ?, 30 ? and 40 ? was measured and the model parameters of the NRTL and UNIQUAC equation was associated. The error of the simulation results and experimental results was analyzed. The results showed that the UNIQUAC and NRTL model can be well associated with the ternary liquid-liquid equilibrium system.On the basis of simulation calculation, multilevel cross-flow extraction experiment was carried out under the comprehensive influence of the solvent ratio and extraction flow. The results showed that under the condition of solvent ratio S: F = 0.8:1, the content of n-hexane in the extraction phase was above 99.50% with the secondary cross-flow extraction and recovery rate of IPA was over 99.50% at the same time.Further more, the continuous countercurrent liquid-liquid extraction process was simulated and carried out. The turntable extraction tower was used to separate n-hexane-IPA mixed system and the effect of continuous counter-current extraction solvent ratio on the results was investigated. The result showed that the theory of series rotary extraction tower for magnitude 4, the solvent ratio (S: F) for 1:1, the content of n-hexane was 99.43% through a continuous extraction.In view of the separation of IPA-water mixture in extraction phase, the scheme of extractive distillation separation process was put forward to achieve the efficiently recycle of IPA in this paper.The methods of multilevel cross-flow liquid-liquid extraction and reflux turntable extraction paper using water as extracting agent to separate n-hexane-IPA binary system process was put forward in this paper and the technological parameters of the two methods was designed and optimized. The work of this paper realized efficiently recycle of n-hexane-IPA system and provided basic data for the design of industrial separation device.