Adsorptive Desulfurization of Bioethanol-Derived Propylene Using Porous Iron Oxide

In the development of the ethanol-to-olefin (ETO) conversion process to produce polymer-grade propylene from cellulosic bioethanol which contained an organosulfur impurity, adsorptive desulfurization of propylene using porous iron oxide (PIO) was examined. We evaluated the performance of PIO for the adsorption of hydrogen sulfide (HS), which was changed from the organosulfur impurity in bioethanol during the ETO conversion, by the measurement of a packed-bed breakthrough curve in a gas phase under the different temperature and pressure. We confirmed that PIO was capable of removing HS selectively from the mixed gas containing propylene, because of the reactivity of PIO with HS even at low temperature. The amount of adsorbed HS on PIO was found to increase with the increase in the temperature or pressure. As a result, the concentration of HS in the desulfurized gas could be reduced lower than 10 ppb.