Separation Of Saturated Alkanes From High Temperature Fischer Tropsch Synthetic Oil

High temperature Fischer Tropsch synthetic oil's main components are saturated n-alkanes and isoalkanes though hydrofining,and the main components of the product are saturated n-alkanes and isoalkanes with the same carbon number after single carbon separation in the pilot distillation column,The purification and separation of n-alkane model feedstock with high mass fraction were studied by urea complexation method,and the crystal characteristics of different guest molecular complexes were characterized and analyzed.(1)In this paper,the urea's solubility in seven pure solvents and two mixed solvents were measured under the condition of atmospheric pressure and 283.15 K-323.15 K through laser dynamic monitoring technology.The phase equilibrium parameters were fitted by Apelblat model,van't Hoff model,Wilson model and NRTL thermodynamic model,The thermodynamic parameters of the mixture were calculated.(2)Based on the phase equilibrium parameters of urea,80%nhexadecane and 20%i-hexadecane were used as model feedstocks for purification and separation of urea;Using i-propanol as activator,the highest yield was 91.98%under the conditions of urea/raw oil 6,urea/activator 0.7,urea/water 2 and reaction temperature 150C;Under the conditions of urea/raw oil 4,urea/activator 0.7,urea/water 1.6 and temperature 15?,the highest purity is expected to reach 99%or above.(3)The channel structure and melting state of C16 complex crystal cell at different temperatures were simulated by molecular dynamics;The crystal characteristics,crystal stability and complex efficiency of C12,C15 and C18 complexes were studied by XRD,DSC,IR and optical microscope.(4)A pilot scale distillation column was designed and installed by Aspen Plus process simulation software.The refined hydrotreated high temperature Fischer Tropsch synthetic oil was separated by vacuum distillation,and the purity of mono alkanes below C20 was about 99%;During the pilot test,the actual temperature of the tower bottom is generally higher than the simulation value,which is related to the actual reflux ratio,reflux temperature at the top of the tower,pressure drop of the whole tower and air tightness of the unit.