Study On Removal Of Alkaline Nitrides In Simulated Oil By Functional Acidic Liquid

The standards on the nitrogen content in fuel oils are put forward by the countries around the world because of the stringent regulations on the environment, for this reason, there are more requirements for fuel oil denitrogenation technology. The extraction denitrogenation technology with ionic liquids (ILs) has many advantages such as simple techniques, mild conditions and the N-compounds can be removed without altering the structure of the fuel-containing compounds. As a new type of denitrogenation technology, extraction-oxidation coupling has superior performance in removing compounds thoroughly; it has shown a good application in denitrogenation.In this paper, the Br(?)nsted acidic ionic liquids were used to remove the basic N-compounds from model oil. One Bronsted acidic ionic liquid N-butylpyridine hydrosulphate ([BPy]HSO4) and two task-specific acidic ionic liquids with different anions N-carboxymethylpyridine nitrate ([CH2COOHPy]NO3) and N-carboxymethylpyridine hydrosulphate ([CH2COOHPy]HSO4) were respectively synthesized by two-step method. The properties of the ionic liquids like dissolubility, density, viscosity, acid strength and denitrogenation performance were studied. The effect of the physicochemical properties on denitrogenation efficiency was discussed. The results showed that all of the prepared ionic liquids are polar solvents. Their densities and viscosities both declined with the temperature rising. At the same temperature, their densities and viscosities were in the order: [CH2COOHPy]HSO4>[BPy]HSO4>[CH2COOHPy] NO3. The acid strength of ionic liquids was in the order:[CH2COOHPy]HSO4> [BPy]HSO4> [CH2COOHPy]NO3. In the same extraction conditions, the extraction capacity of the ILs was in the order: [CH2COOHPy]HSO4> [BPy]HSO4> [CH2COOHPy]NO3.The task-specific acidic ionic liquid [CH2COOHPy]HSO4 which had the best performance of denitrogenation was selected to investigate the effect of IL: oil mass ratio(w/w) and the main technological parameters on N-extraction efficiency under the conditions of power ultrasound and constant temperature oscillation. The results showed that when IL: oil mass ratio is 1: 2, in the constant temperature oscillation condition (rotation speed is 180rpm, at 50℃ for 20min) the N-extraction efficiency is 95.12%; in the power ultrasound condition (ultrasonic power is 500W, ultrasonic frequency is 59kHz, at 25℃ for 15min)the N-extraction efficiency can reach 98.26%.The task-specific acidic ionic liquid [CH2COOHPy]HSO4 was used in the research of extraction-oxidation coupling denitrogenation. The technological conditions were optimized and the recycle of ionic liquid was investigated. The optimized conditions of extraction-oxidation coupling denitrogenation were:IL:oil mass ratio was 1:10, n(H2O2): n(N)=4, the reaction time was 40min at 50℃, the denitrogenation efficiency can reach 99.67%. The regenerated ILs were analyzed by FT-IR, it was demonstrated that there was no significant change in its chemical structure. The ionic liquid can be reused 5 times by regeneration without obvious decrease in N-extraction efficiency.