Evaluation Of Thermodynamic Model For Alcohol Separation Process Of Fischer-Tropsch Synthesis Water

F-T synthesis reaction produces large amounts of water and lots of oxygen-containing by-products.The water can not be discharged directly because the oxygen-containing by-products dissolved in the water.Commonly,the distillation method can be used in seperating such waste water,while the basic problem for designing the distillation equipment is the phase equilibrium data.At present,the current lack of the equilibrium data for separating the alcohol in F-T process,are mainly about the long-chain alcohols.Therefore,the basic phase equilibrium data,physical property estimation and thermodynamic method are still need to be obtained by vapor liquid equilibrium experiments.And then the reliable thermodynamic method can be found in these systems.The dissertation is mainly for the system of water-alcohol/alcohol binary systems parameters,and the binary phase equilibrium data of ethanol-2-pentanol,ethanol-heptanol,2-pentanol-heptanol,methanol-hexanol,ethanol-hexanol under atmospheric pressure were measured by circular glass vapor-liquid equilibrium device.Then the ternery system of ethanol-2-pentanol-heptanol and methanol-ethanol-hexanol were further determined.The binary parameters of activity coefficient models of Wilson,NRTL and UNIQUAC were obtained by regression of these binary phase equilibrium datas.Furethermore,the VLE data of ternary systems were predicted using these binary parameters and compared with the obtained experimental results.The results show that the above-mentioned systems can be calculated by NRTL,NRTL-HOC,Wilson,Wilson-HOC,UNIQUAC,UNIQUAC-HOC activity coefficient models.When calculated by NRTL-HOC model,the average deviation of temperature in ethanol-2-pentanol-heptanol ternary VLE system is about 1.0 °C and the average deviation of VLE data is 4.2569%.The average deviation of temperature in methanol-ethanol-hexanol ternary system is 1.0 °C and the average deviation is 3.4687%.When calculated by UNIQUAC-HOC activity coefficient model,the average deviation of temperature is 1.0 °C and the average deviation of VLE data is 3.5412%.The results also show that in the long-chained alcohol systems,the calculated deviations with the experimental values can be smaller through the correction of Hayden-O'Connell state equation in vapor phase,and the average deviation of VLE data generally is no more than 5.5%.It can be seen that the calculation in long-chained alcohol systems,it should be considered deviation between the ideal system and the real one.By the determination and calculation of phase equilibrium data of the alcohol-water and alcohol-alcohol systems,the results can provide reliable phase equilibrium data and activity coefficient model parameter for alcohol/water-alcohol systems,and can also provide reliable thermodynamic datas used in the calculation of alcohol separation process in the treatment of F-T synthesis water process.