Abstract:
Recently, air pollution becomes a serious concern in an environmental issue. The concentrations of sulfur and nitrogen compounds in diesel are accordingly required to be strictly controlled. Adsorption is one of the effective method to decrease the levels of sulfur and nitrogen compounds in diesel. Therefore, this work focused on the effect of Y-zeolite consisting of various metals such as Na-Y, Ni-Y, Cu-Y, Co-Y, La-Y, Ce-Y and Fe-Y on adsorptive desulfurization and denitrogenation. Under ambient condition, La-Y zeolite exhibited the best adsorption efficiency for nitrogen compounds (model oil 4), while Na-Y zeolite showed the maximum adsorption capacity for sulfur compounds (model oil 1) in a single-stage column system. For the double-stage system, the first stage contained La-Y zeolite for adsorptive denitrogenation and the second stage was loaded with Na-Y zeolite for adsorptive desulfurization. The total adsorption capacity of nitrogen compounds was 65.6%, 49.2% and 39.9% for quinoline, indole and acridine, respectively. Whereas, the total adsorption capacity of sulfur compounds was 38.8% and 37.7% for DBT and 4,6 DMDBT, respectively. The results indicated that the double-stage column system using La-Y and Na-Y zeolites was appropriate route for desulfurization and denitrogenation of diesel oil. And the adsorptive desulfurization and denitrogenation in both single-stage and double-stage system, the escalation in temperature increased the adsorption efficiency. In addition, the La-Y and Na-Y zeolites could be regenerated by the solvent extraction method in the double-stage system for the next adsorption cycle.