Preparation of mesoporous MCM-41 supported zinc sorbents by microwave in-situ oxidation for H2S removal in coal gas

摘要

Zn-based MCM-41 supporter sorbents were prepared using the microwave in-situ oxidation method. Other sorbents were heated using a conventional heating method to contrast the performance for H2S removal. The sorbents were tested at 500 degrees C in fixed reactor and dried simulated Texaco coal gas was employed for the sulphurized atmosphere. The results show that sorbents prepared by microwave oxidation had a better toleration for the adsorption of H2S. A 13.2% improvement occurred in the sulphur capacity of the sorbents heated by the microwave method. XRD, SEM with EDS-element mapping, TEM, N-2 adsorption, and XPS were used to characterize the properties of the sorbents. Due to the selective heating of the microwave and the superiority of the in-situ oxidation method, the sorbents heated by microwave exhibited more appropriate structures for sulphurization. Meanwhile, the even heating environment supplied by the microwave resulted in a more uniform distribution of the active component. The microwave also had an effect on the chemical bond and reduced the binding energy of the active component, which enhanced the reactivity between the H2S and the sorbents. The preferable features generated by microwave in-situ oxidation accelerate the replacement of S to O, and therefore the Zn-based MCM-41 sorbents prepared by the microwave method have an increased capability for H2S removal in high temperature coal gas.