| Environmental protection is the theme of 21 century, desulfurization has been an important and impendence mission. Many scientists are researching new technologies of non-hydrogenation desulfurization. Specially, oxidation desulfurization and iron liquid extraction desulfurization are emphases. In this paper, oxidation-extraction desulfurization, two Step Oxidation desulfurization, oxidation desulfurization after cut fraction and iron liquids extraction desulfurization were studied.⑴Oxidation-Extraction desulfurizationThe techniques of all-fraction gasoline's oxidation-extraction desulfurization were studied and the optimized reaction conditions were obtained through the single factor experiment:①Oxidation: 70g all-fraction gasoline(sulfur content 900.4ppm), 20.0g peroxide hydrogen (content 30%), 40mL formic acid(content 88%), the reaction temperature was 55℃, the reaction time was 10min. After oxidation, 62.2g of gasoline was obtained and the yield was 89.5%, sulfur content was 674.9ppm.②Extraction: DMF(content 90%) as extractant, the volume ratio of extractant to gasoline is 0.9:1, extractive time was 5min, the extractive temperature was 40℃. On extraction the yield oxidated gasoline was 81.2%, sulfur content was 265.2ppm.③Recovery of extractant: Use distillation to recovery extractant, every factor tended to stability after 5 time recirculates. Therefore, it proved the recovery method was feasible.⑵Two Step Oxidation desulfurizationThe techniques of all-fraction gasoline's two step oxidation desulfurization without extractant were studied and the optimized reaction conditions were obtained through the single factor experiment:①First Step Oxidation: 70g all-fraction gasoline(sulfur content 900.4ppm), 20.0g peroxide hydrogen (content 30%), 40mL formic acid(content 88%), the reaction temperature was 55℃, the reaction time was 10min. After oxidation, 62.2g of gasoline was obtained and the yield was 89.5%, sulfur content was 674.9ppm.②Second Step Oxidation: 62.6g oxidated gasoline(sulfur content 647.9ppm), 12.5g peroxide hydrogen(content 30%), 20mL formic acid(content 88%), the reaction temperature was 80℃, the reaction time was 15min. After second step oxidation, 57.6g of gasoline was obtained and the yield was 92.0%, sulfur content was 323.3ppm.⑶Oxidation desulfurization after cut fraction The techniques of cut-fractioned gasoline's oxidation desulfurization without extractant were studied, light fraction was washed with alkali and heavy fraction was oxidative. The optimized reaction conditions were obtained through the single factor experiment:①The temperature of cut fraction is 80℃, light fraction's sulfur content is 228.9ppm, heavy fraction's sulfur content is 1397.5ppm.②After washing with 10%NaOH(5%volume) for 5min, light fraction's sulfur content was 161.36ppm. According to weight ratio of light fraction and heavy fraction, if processed all-fraction gasoline's sulfur content is less than 500ppm, heavy fraction sulfur content is less than 686.24ppm.③Heavy fraction was desulfurized by formic acid- hydrogen peroxide oxidation. 50g heavy fraction (sulfur content 647.9ppm), 10g peroxide hydrogen(content 30%), 15mL formic acid (content 88%), the reaction temperature was 95℃, the reaction time was 10min. After oxidation, 43.9g gasoline was obtained and the yield was 87.8%, sulfur content was 557.908ppm. After mixed with light fraction, gasoline's sulfur content was less than 500ppm.④Recovery of formic acid: Isopropyl ether as azeotropic solution, every factor tend to stability after 5 time recirculates. Therefore, it proved the recovery method was feasible.⑷In the preparation of the iron liquids, because of the steric hinders, with the growth of the carbon chains in the N-alkylation reaction, the reactivity was lowered; The ion exchange reaction was related to the ion concentration but irrelative to the alkyl chain.In the experiments of the extraction desulfurization, when the iron liquids have the same cationic substituent alkyl, anionic BF4- was better than the PF6-. The iron liquids have higher desulfurization rate when longer alkyl was linked to the cationic part with the same anionic part. We obtained the best results with the use of the [OctMeIm]BF4 and [OctPy]BF4. When we added this two iron liquids into formic acid- hydrogen peroxide system, the yield of the gasoline had not significant change but the desulfurization capacity of the system was enhanced. The [OctMeIm]BF4 of the alkyl imidazole ionic liquids had higher desulfurization rate than the [OctPy]BF4 of the alkyl Pyridine ionic liquids.
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