The Research And Application Of The Denitrogenation Methods For Diesel Oil

Diesel oil is one of the engine fuels having largest consumption in China at present, but the nitrogen-containing organic compounds in diesel oil are harmful to production and environment. They have a big effect on the chroma of oil, reduce the anti-oxidation stability of oil. Therefore the storage and using performance are also influenced. Furthermore they inactivate refining catalyst in diesel oil catalyzed processing. And some nitrogen-containing organic compounds have mutagenic and toxic activities, their combustion leads to the formation of nitrogen oxides (NOX), which is one of the important air pollutants forming acid rain. The classical hydrodenitrogenation is costly and complicated. Therefore, non-hydrodenitrogenation technics are utilized. Carbazole was selected in this text as a model compound on biodenitrogenation study of diesel oil. The influence of direct current field on the strain growth rate and denitrogenation activities was discussed at the same time. Ultrasonically auxiliary oxidation by Ce4+ was used to desulfurize and denitrogenize the diesel oil simultaneously.The main contents of the thesis are as follows:A new strain able to convert carbazole into anthranilic acid was isolated from the sullage and soil samples polluted by fuel oil and was identified as pseudomonas aeruginos YSSH. Taking the denitrogenation rate of carbazole as an evaluating indicator, the orthogonal experiment was used to exam the effects of initial pH, rapidly available sources of carbon (glucose) and nitrogen (ammonium chloride) on growth and biodenitrogenation rate. The optimum conditions for the growth and biodenitrogenation were 1.0 g/L of ammonium chloride, the initial pH 7.0, and 3.0 g/L of glucose. When applied in the diesel oil system, it removed 63.9% of 100 ppm total nitrogen content in the diesel oil under the oil-water ratio of 1:9.Taking cell thickness and denitrogenation rate of carbazole as evaluating indicators, applied direct current field stimulation of different intensity to the isolated strain, and studied the influence of adscititious electric field on the strain growth rate and denitrogenation activities. The experiment proved that the strain denitrogenation activities was highest when the current intensity was 10.0 mA, but when the current intensity increased up to 20.0 mA and 40.0 mA, the strain denitrogenation activities was restrained obviously. Applied the results to the diesel oil system (the oil-water ratio is 1:9), the denitrogenation rate in diesel oil did not improve compared with the results of that without the electric field stimulation.Used the Ce4+ to oxidize the sulfur and nitrogen compounds in diesel oil simultaneously under ultrasonic auxiliary conditions, and removed the oxidation products by choosing a proper solvent DMF to extract them, it reduced the total sulfur content in diesel oil from 11000 ppm to 6500 ppm, achieving a desulfurization rate of 40.9%, and reduced the total nitrogen content in diesel oil from 100 ppm to 44.6 ppm, achieving a denitrogenation rate of 55.4% simultaneously. The best denitrogenation conditions obtained from the experiment was that the reaction temperature was 70℃, the solution pH value was 0.7, the reaction time was 50 min, and the oil-water ratio was 1:9.