Preparation And Deep Desulfurization Performance Evaluation Of Modified Adsorbents

Cleaner and environmental-friendly fuel oil must be required due to new more stringent regulations and fuel specification in a world-wide consensus for an environmental protection purpose in recent years.A promising approach for deep desulfurization is to use adsorption to selectively remove organic sulfur compounds from liquid oils.adsorption desulfrization has the following potential advantages:(1) The process is operated at ambient temperature and atmosphere,without using any H₂,which leads to a low energy consumption,Low investment and low operating cost;(2) The process has a very effective desorption to sulfur-containing condensed aromatic compounds,while HDS can't.In the present study three modified NaY zeolites(i.e.CeY,CuY and CeCuY) as sorbents were prepared by conventional ion exchange method under hydrothermal conditions.At the same time,(1) Some important preparation parameters on the Ce³⁺ exchange ratio and desulfurization performance on CeY zeolites were systematically investigated.Our results showed the suitable preparation conditions of CeY are: cerous nitrate 0.35 mol/l,NaY/solution ratio 0.05,exchange temperature 155℃, exchange time 2 days;and CeY with different Ce ion content demonstrated the same desulfurization behaviors under the same adsorptive conditions.(2) desulfurization efficiency in three model oil over CeY,CuY and CeCuY were surveyed under ambient temperature and pressure,the results indicated desulfurization rate in model gasoline A and B are above 95%,while which in model gasoline C is about 60%.A mechanistic investigation by IR and BET revealed that the complexity and indefinability of adsorption mechanism on modified NaY zeolites.It was not acted only for molecule size selection or the complexation between sorbents and sulfurides.A elementary trial was done about the desulfurization performance in model gasoline A over modified actived carbons.It showed desulfurization rates of actived carbons treated with strong acid,original actived carbon and acticved carbons calcined in N₂ atmosphere are about 44.6%,52.3%,60.0%.A characteristic result of actived carbons calcined in N₂ atmosphere by BET suggested the difference of desulfurization rate was not due to the changes of pore structure.