Detailed Separation And Non-catalytic Oxidation Modification Of Fischer Tropsch Wax

As the main intermediate product in the process of coal-to-oil,Fischer-Tropsch wax is usually converted into liquid oil for sale by domestic coal-to-oil enterprises.However,the separated and modified Fischer-Tropsch wax can obtain higher added value as a high-end chemical.Herein,the hydrofined Fischer Tropsch wax was used as raw materials,and the fine separation and non-catalytic oxidation modification were applied for the hydrofined Fischer Tropsch wax,which could provide theoretical guidance for obtaining value-added chemicals from Fischer-Tropsch wax.（1）The chemical composition of Fischer-Tropsch wax was studied.The n-alkanes in Fischer Tropsch wax have high content and wide distribution of carbon number,and the carbon number is up to C₈₅.While the content of isoalkanes and alkenes is relatively less.Moreover,the content of alkanes with carbon number above C₅₀in Fischer-Tropsch wax is14.49%,which is the ideal raw material for making high-end Fischer-Tropsch wax.（2）The Fischer-Tropsch wax was separated by step vacuum distillation.The influence of the distillation pressure,temperature,and time on the extraction rate and final distillation point of FT-1 and FT-2 were explored.The results are as follows:The desired FT-1 can be separated at a distillation pressure of 1 Torr,cut-off temperature of 250℃,and condensation temperature of 60℃.The desired FT-2 can be separated at a distillation pressure of 1 Torr,cut-off temperature of 300℃,and condensation temperature of 80℃.（3）n-heptane and n-hexadecane were selected as extraction solvents to extract heavy phase wax obtained by vacuum distillation.The influences of the ratio of wax to solvent,extraction temperature,and extraction time on the composition of the extract were studied respectively.The results showed that the FT-3 could be separated when the ratio of wax to solvent was 2:1,the extraction temperature was 90℃,and the extraction time was 20minutes;FT-4 and FT-5 were obtained at the ratio of wax to solvent of 3:1,extraction temperature of 100℃,and extraction time of 30 minutes.（4）Finally,the non-catalytic oxidation modification of FT-3 and FT-5 were explored.The results are as follows:as for FT-3,when the reaction temperature is 140℃,the reaction time is 6 hours,the intensity of ultraviolet is 6 m W/cm²and the oxygen flow rate is 300 m L min^-1,the oxidation wax with an acid value of 16.1 mg KOH/g and a saponification value of41.9 mg KOH/g can be obtained.With regard for FT-5,when the reaction temperature is150℃,the reaction time is 7 hours,the intensity of ultraviolet is 6 m W/cm²and the oxygen flow rate is 350 m L min^-1,the oxidation wax with an acid value of 14.2 mg KOH/g and a saponification value of 37.1 mg KOH/g can be obtained.